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Hypertriton Production in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2022; 128:252003. [PMID: 35802430 DOI: 10.1103/physrevlett.128.252003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 01/28/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
The study of nuclei and antinuclei production has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. The first measurement of the production of _{Λ}^{3}H in p-Pb collisions at sqrt[s_{NN}]=5.02 TeV is presented in this Letter. Its production yield measured in the rapidity interval -1<y<0 for the 40% highest-multiplicity p-Pb collisions is dN/dy=[6.3±1.8(stat)±1.2(syst)]×10^{-7}. The measurement is compared with the expectations of statistical hadronization and coalescence models, which describe the nucleosynthesis in hadronic collisions. These two models predict very different yields of the hypertriton in charged particle multiplicity environments relevant to small collision systems such as p-Pb, and therefore the measurement of dN/dy is crucial to distinguish between them. The precision of this measurement leads to the exclusion with a significance larger than 6.9σ of some configurations of the statistical hadronization model, thus constraining the theory behind the production of loosely bound states at hadron colliders.
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Polarization of Λ and Λ[over ¯] Hyperons along the Beam Direction in Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV. PHYSICAL REVIEW LETTERS 2022; 128:172005. [PMID: 35570422 DOI: 10.1103/physrevlett.128.172005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 01/04/2022] [Accepted: 03/16/2022] [Indexed: 06/15/2023]
Abstract
The polarization of the Λ and Λ[over ¯] hyperons along the beam (z) direction, P_{z}, has been measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV recorded with ALICE at the Large Hadron Collider (LHC). The main contribution to P_{z} comes from elliptic flow-induced vorticity and can be characterized by the second Fourier sine coefficient P_{z,s2}=⟨P_{z}sin(2φ-2Ψ_{2})⟩, where φ is the hyperon azimuthal emission angle and Ψ_{2} is the elliptic flow plane angle. We report the measurement of P_{z,s2} for different collision centralities and in the 30%-50% centrality interval as a function of the hyperon transverse momentum and rapidity. The P_{z,s2} is positive similarly as measured by the STAR Collaboration in Au-Au collisions at sqrt[s_{NN}]=200 GeV, with somewhat smaller amplitude in the semicentral collisions. This is the first experimental evidence of a nonzero hyperon P_{z} in Pb-Pb collisions at the LHC. The comparison of the measured P_{z,s2} with the hydrodynamic model calculations shows sensitivity to the competing contributions from thermal and the recently found shear-induced vorticity, as well as to whether the polarization is acquired at the quark-gluon plasma or the hadronic phase.
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Measurement of the Groomed Jet Radius and Momentum Splitting Fraction in pp and Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2022; 128:102001. [PMID: 35333086 DOI: 10.1103/physrevlett.128.102001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/29/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
This article presents groomed jet substructure measurements in pp and Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector. The soft drop grooming algorithm provides access to the hard parton splittings inside a jet by removing soft wide-angle radiation. We report the groomed jet momentum splitting fraction, z_{g}, and the (scaled) groomed jet radius, θ_{g}. Charged-particle jets are reconstructed at midrapidity using the anti-k_{T} algorithm with resolution parameters R=0.2 and R=0.4. In heavy-ion collisions, the large underlying event poses a challenge for the reconstruction of groomed jet observables, since fluctuations in the background can cause groomed parton splittings to be misidentified. By using strong grooming conditions to reduce this background, we report these observables fully corrected for detector effects and background fluctuations for the first time. A narrowing of the θ_{g} distribution in Pb-Pb collisions compared to pp collisions is seen, which provides direct evidence of the modification of the angular structure of jets in the quark-gluon plasma. No significant modification of the z_{g} distribution in Pb-Pb collisions compared to pp collisions is observed. These results are compared with a variety of theoretical models of jet quenching, and provide constraints on jet energy-loss mechanisms and coherence effects in the quark-gluon plasma.
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Measurement of Prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) Production in Proton-Proton Collisions at sqrt[s]=13 TeV. PHYSICAL REVIEW LETTERS 2022; 128:012001. [PMID: 35061479 DOI: 10.1103/physrevlett.128.012001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/09/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
The p_{T}-differential production cross sections of prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) charmed hadrons are measured at midrapidity (|y|<0.5) in pp collisions at sqrt[s]=13 TeV. This is the first measurement of Σ_{c}^{0,++} production in hadronic collisions. Assuming the same production yield for the three Σ_{c}^{0,+,++} isospin states, the baryon-to-meson cross section ratios Σ_{c}^{0,+,++}/D^{0} and Λ_{c}^{+}/D^{0} are calculated in the transverse momentum (p_{T}) intervals 2<p_{T}<12 and 1<p_{T}<24 GeV/c. Values significantly larger than in e^{+}e^{-} collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the Σ_{c}. The feed-down contribution to Λ_{c}^{+} production from Σ_{c}^{0,+,++} is also reported and is found to be larger than in e^{+}e^{-} collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronization mechanisms implemented in the models.
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Measurement of the Cross Sections of Ξ_{c}^{0} and Ξ_{c}^{+} Baryons and of the Branching-Fraction Ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+}) in pp Collisions at sqrt[s]=13 TeV. PHYSICAL REVIEW LETTERS 2021; 127:272001. [PMID: 35061415 DOI: 10.1103/physrevlett.127.272001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/18/2021] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
The p_{T}-differential cross sections of prompt charm-strange baryons Ξ_{c}^{0} and Ξ_{c}^{+} were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy sqrt[s]=13 TeV with the ALICE detector at the LHC. The Ξ_{c}^{0} baryon was reconstructed via both the semileptonic decay (Ξ^{-}e^{+}ν_{e}) and the hadronic decay (Ξ^{-}π^{+}) channels. The Ξ_{c}^{+} baryon was reconstructed via the hadronic decay (Ξ^{-}π^{+}π^{+}) channel. The branching-fraction ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+})=1.38±0.14(stat)±0.22(syst) was measured with a total uncertainty reduced by a factor of about 3 with respect to the current world average reported by the Particle Data Group. The transverse momentum (p_{T}) dependence of the Ξ_{c}^{0}- and Ξ_{c}^{+}-baryon production relative to the D^{0} meson and to the Σ_{c}^{0,+,++}- and Λ_{c}^{+}-baryon production are reported. The baryon-to-meson ratio increases toward low p_{T} up to a value of approximately 0.3. The measurements are compared with various models that take different hadronization mechanisms into consideration. The results provide stringent constraints to these theoretical calculations and additional evidence that different processes are involved in charm hadronization in electron-positron (e^{+}e^{-}) and hadronic collisions.
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6
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Experimental Evidence for an Attractive p-ϕ Interaction. PHYSICAL REVIEW LETTERS 2021; 127:172301. [PMID: 34739260 DOI: 10.1103/physrevlett.127.172301] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
This Letter presents the first experimental evidence of the attractive strong interaction between a proton and a ϕ meson. The result is obtained from two-particle correlations of combined p-ϕ⊕ p[over ¯]-ϕ pairs measured in high-multiplicity pp collisions at sqrt[s]=13 TeV by the ALICE Collaboration. The spin-averaged scattering length and effective range of the p-ϕ interaction are extracted from the fully corrected correlation function employing the Lednický-Lyuboshits approach. In particular, the imaginary part of the scattering length vanishes within uncertainties, indicating that inelastic processes do not play a prominent role for the p-ϕ interaction. These data demonstrate that the interaction is dominated by elastic p-ϕ scattering. Furthermore, an analysis employing phenomenological Gaussian- and Yukawa-type potentials is conducted. Under the assumption of the latter, the N-ϕ coupling constant is found to be g_{N-ϕ}=0.14±0.03(stat)±0.02(syst). This work provides valuable experimental input to accomplish a self-consistent description of the N-ϕ interaction, which is particularly relevant for the more fundamental studies on partial restoration of chiral symmetry in nuclear medium.
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Soft-Dielectron Excess in Proton-Proton Collisions at sqrt[s]=13 TeV. PHYSICAL REVIEW LETTERS 2021; 127:042302. [PMID: 34355943 DOI: 10.1103/physrevlett.127.042302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 04/12/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
A measurement of dielectron production in proton-proton (pp) collisions at sqrt[s]=13 TeV, recorded with the ALICE detector at the CERN LHC, is presented in this Letter. The data set was recorded with a reduced magnetic solenoid field. This enables the investigation of a kinematic domain at low dielectron (ee) invariant mass m_{ee} and pair transverse momentum p_{T,ee} that was previously inaccessible at the LHC. The cross section for dielectron production is studied as a function of m_{ee}, p_{T,ee}, and event multiplicity dN_{ch}/dη. The expected dielectron rate from hadron decays, called hadronic cocktail, utilizes a parametrization of the measured η/π^{0} ratio in pp and proton-nucleus collisions, assuming that this ratio shows no strong dependence on collision energy at low transverse momentum. Comparison of the measured dielectron yield to the hadronic cocktail at 0.15<m_{ee}<0.6 GeV/c^{2} and for p_{T,ee}<0.4 GeV/c indicates an enhancement of soft dielectrons, reminiscent of the "anomalous" soft-photon and soft-dilepton excess in hadron-hadron collisions reported by several experiments under different experimental conditions. The enhancement factor over the hadronic cocktail amounts to 1.61±0.13(stat)±0.17(syst,data)±0.34(syst,cocktail) in the ALICE acceptance. Acceptance-corrected excess spectra in m_{ee} and p_{T,ee} are extracted and compared with calculations of dielectron production from hadronic bremsstrahlung and thermal radiation within a hadronic many-body approach.
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Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2021; 126:162001. [PMID: 33961482 DOI: 10.1103/physrevlett.126.162001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 01/27/2021] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The azimuthal distribution of the particles produced in the collisions can be parametrized with a Fourier expansion, in which the second harmonic coefficient represents the elliptic flow, v_{2}. The v_{2} coefficient of electrons from beauty hadron decays is measured for the first time in the transverse momentum (p_{T}) range 1.3-6 GeV/c in the centrality class 30%-50%. The measurement of electrons from beauty-hadron decays exploits their larger mean proper decay length cτ≈500 μm compared to that of charm hadrons and most of the other background sources. The v_{2} of electrons from beauty hadron decays at midrapidity is found to be positive with a significance of 3.75 σ. The results provide insights into the degree of thermalization of beauty quarks in the medium. A model assuming full thermalization of beauty quarks is strongly disfavored by the measurement at high p_{T}, but is in agreement with the results at low p_{T}. Transport models including substantial interactions of beauty quarks with an expanding strongly interacting medium describe the measurement within uncertainties.
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Measurement of the Low-Energy Antideuteron Inelastic Cross Section. PHYSICAL REVIEW LETTERS 2020; 125:162001. [PMID: 33124836 DOI: 10.1103/physrevlett.125.162001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/10/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
In this Letter, we report the first measurement of the inelastic cross section for antideuteron-nucleus interactions at low particle momenta, covering a range of 0.3≤p<4 GeV/c. The measurement is carried out using p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sqrt[s_{NN}]=5.02 TeV, recorded with the ALICE detector at the CERN LHC and utilizing the detector material as an absorber for antideuterons and antiprotons. The extracted raw primary antiparticle-to-particle ratios are compared to the results from detailed ALICE simulations based on the geant4 toolkit for the propagation of (anti)particles through the detector material. The analysis of the raw primary (anti)proton spectra serves as a benchmark for this study, since their hadronic interaction cross sections are well constrained experimentally. The first measurement of the inelastic cross section for antideuteron-nucleus interactions averaged over the ALICE detector material with atomic mass numbers ⟨A⟩=17.4 and 31.8 is obtained. The measured inelastic cross section points to a possible excess with respect to the Glauber model parametrization used in geant4 in the lowest momentum interval of 0.3≤p<0.47 GeV/c up to a factor 2.1. This result is relevant for the understanding of antimatter propagation and the contributions to antinuclei production from cosmic ray interactions within the interstellar medium. In addition, the momentum range covered by this measurement is of particular importance to evaluate signal predictions for indirect dark-matter searches.
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Probing the Effects of Strong Electromagnetic Fields with Charge-Dependent Directed Flow in Pb-Pb Collisions at the LHC. PHYSICAL REVIEW LETTERS 2020; 125:022301. [PMID: 32701333 DOI: 10.1103/physrevlett.125.022301] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/22/2020] [Accepted: 05/19/2020] [Indexed: 06/11/2023]
Abstract
The first measurement at the LHC of charge-dependent directed flow (v_{1}) relative to the spectator plane is presented for Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV. Results are reported for charged hadrons and D^{0} mesons for the transverse momentum intervals p_{T}>0.2 GeV/c and 3<p_{T}<6 GeV/c in the 5%-40% and 10%-40% centrality classes, respectively. The difference between the positively and negatively charged hadron v_{1} has a positive slope as a function of pseudorapidity η, dΔv_{1}/dη=[1.68±0.49(stat)±0.41(syst)]×10^{-4}. The same measurement for D^{0} and D[over ¯]^{0} mesons yields a positive value dΔv_{1}/dη=[4.9±1.7(stat)±0.6(syst)]×10^{-1}, which is about 3 orders of magnitude larger than the one of the charged hadrons. These measurements can provide new insights into the effects of the strong electromagnetic field and the initial tilt of matter created in noncentral heavy ion collisions on the dynamics of light (u, d, and s) and heavy (c) quarks. The large difference between the observed Δv_{1} of charged hadrons and D^{0} mesons may reflect different sensitivity of the charm and light quarks to the early time dynamics of a heavy ion collision. These observations challenge some recent theoretical calculations, which predicted a negative and an order of magnitude smaller value of dΔv_{1}/dη for both light flavor and charmed hadrons.
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Evidence of Spin-Orbital Angular Momentum Interactions in Relativistic Heavy-Ion Collisions. PHYSICAL REVIEW LETTERS 2020; 125:012301. [PMID: 32678650 DOI: 10.1103/physrevlett.125.012301] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/25/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
The first evidence of spin alignment of vector mesons (K^{*0} and ϕ) in heavy-ion collisions at the Large Hadron Collider (LHC) is reported. The spin density matrix element ρ_{00} is measured at midrapidity (|y|<0.5) in Pb-Pb collisions at a center-of-mass energy (sqrt[s_{NN}]) of 2.76 TeV with the ALICE detector. ρ_{00} values are found to be less than 1/3 (1/3 implies no spin alignment) at low transverse momentum (p_{T}<2 GeV/c) for K^{*0} and ϕ at a level of 3σ and 2σ, respectively. No significant spin alignment is observed for the K_{S}^{0} meson (spin=0) in Pb-Pb collisions and for the vector mesons in pp collisions. The measured spin alignment is unexpectedly large but qualitatively consistent with the expectation from models which attribute it to a polarization of quarks in the presence of angular momentum in heavy-ion collisions and a subsequent hadronization by the process of recombination.
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Scattering Studies with Low-Energy Kaon-Proton Femtoscopy in Proton-Proton Collisions at the LHC. PHYSICAL REVIEW LETTERS 2020; 124:092301. [PMID: 32202883 DOI: 10.1103/physrevlett.124.092301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 12/03/2019] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
The study of the strength and behavior of the antikaon-nucleon (K[over ¯]N) interaction constitutes one of the key focuses of the strangeness sector in low-energy quantum chromodynamics (QCD). In this Letter a unique high-precision measurement of the strong interaction between kaons and protons, close and above the kinematic threshold, is presented. The femtoscopic measurements of the correlation function at low pair-frame relative momentum of (K^{+}p⊕K^{-}p[over ¯]) and (K^{-}p⊕K^{+}p[over ¯]) pairs measured in pp collisions at sqrt[s]=5, 7, and 13 TeV are reported. A structure observed around a relative momentum of 58 MeV/c in the measured correlation function of (K^{-}p⊕K^{+}p[over ¯]) with a significance of 4.4σ constitutes the first experimental evidence for the opening of the (K[over ¯]^{0}n⊕K^{0}n[over ¯]) isospin breaking channel due to the mass difference between charged and neutral kaons. The measured correlation functions have been compared to Jülich and Kyoto models in addition to the Coulomb potential. The high-precision data at low relative momenta presented in this work prove femtoscopy to be a powerful complementary tool to scattering experiments and provide new constraints above the K[over ¯]N threshold for low-energy QCD chiral models.
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Measurement of ϒ(1S) Elliptic Flow at Forward Rapidity in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2019; 123:192301. [PMID: 31765217 DOI: 10.1103/physrevlett.123.192301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/09/2019] [Indexed: 06/10/2023]
Abstract
The first measurement of the ϒ(1S) elliptic flow coefficient (v_{2}) is performed at forward rapidity (2.5<y<4) in Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The results are obtained with the scalar product method and are reported as a function of transverse momentum (p_{T}) up to 15 GeV/c in the 5%-60% centrality interval. The measured ϒ(1S)v_{2} is consistent with 0 and with the small positive values predicted by transport models within uncertainties. The v_{2} coefficient in 2<p_{T}<15 GeV/c is lower than that of inclusive J/ψ mesons in the same p_{T} interval by 2.6 standard deviations. These results, combined with earlier suppression measurements, are in agreement with a scenario in which the ϒ(1S) production in Pb-Pb collisions at LHC energies is dominated by dissociation limited to the early stage of the collision, whereas in the J/ψ case there is substantial experimental evidence of an additional regeneration component.
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Investigations of Anisotropic Flow Using Multiparticle Azimuthal Correlations in pp, p-Pb, Xe-Xe, and Pb-Pb Collisions at the LHC. PHYSICAL REVIEW LETTERS 2019; 123:142301. [PMID: 31702212 DOI: 10.1103/physrevlett.123.142301] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Indexed: 06/10/2023]
Abstract
Measurements of anisotropic flow coefficients (v_{n}) and their cross-correlations using two- and multiparticle cumulant methods are reported in collisions of pp at sqrt[s]=13 TeV, p-Pb at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02 TeV, Xe-Xe at sqrt[s_{NN}]=5.44 TeV, and Pb-Pb at sqrt[s_{NN}]=5.02 TeV recorded with the ALICE detector. The multiplicity dependence of v_{n} is studied in a very wide range from 20 to 3000 particles produced in the midrapidity region |η|<0.8 for the transverse momentum range 0.2<p_{T}<3.0 GeV/c. An ordering of the coefficients v_{2}>v_{3}>v_{4} is found in pp and p-Pb collisions, similar to that seen in large collision systems, while a weak v_{2} multiplicity dependence is observed relative to nucleus-nucleus collisions in the same multiplicity range. Using a novel subevent method, v_{2} measured with four-particle cumulants is found to be compatible with that from six-particle cumulants in pp and p-Pb collisions. The magnitude of the correlation between v_{n}^{2} and v_{m}^{2}, evaluated with the symmetric cumulants SC(m,n) is observed to be positive at all multiplicities for v_{2} and v_{4}, while for v_{2} and v_{3} it is negative and changes sign for multiplicities below 100, which may indicate a different v_{n} fluctuation pattern in this multiplicity range. The observed long-range multiparticle azimuthal correlations in high multiplicity pp and p-Pb collisions can neither be described by pythia 8 nor by impact-parameter-Glasma, music, and ultrarelativistic quantum molecular dynamics model calculations, and hence, provide new insights into the understanding of collective effects in small collision systems.
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First Observation of an Attractive Interaction between a Proton and a Cascade Baryon. PHYSICAL REVIEW LETTERS 2019; 123:112002. [PMID: 31573229 DOI: 10.1103/physrevlett.123.112002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 06/28/2019] [Indexed: 06/10/2023]
Abstract
This Letter presents the first experimental observation of the attractive strong interaction between a proton and a multistrange baryon (hyperon) Ξ^{-}. The result is extracted from two-particle correlations of combined p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} pairs measured in p-Pb collisions at sqrt[s_{NN}]=5.02 TeV at the LHC with ALICE. The measured correlation function is compared with the prediction obtained assuming only an attractive Coulomb interaction and a standard deviation in the range [3.6, 5.3] is found. Since the measured p-Ξ^{-}⊕p[over ¯]-Ξ[over ¯]^{+} correlation is significantly enhanced with respect to the Coulomb prediction, the presence of an additional, strong, attractive interaction is evident. The data are compatible with recent lattice calculations by the HAL-QCD Collaboration, with a standard deviation in the range [1.8, 3.7]. The lattice potential predicts a shallow repulsive Ξ^{-} interaction within pure neutron matter and this implies stiffer equations of state for neutron-rich matter including hyperons. Implications of the strong interaction for the modeling of neutron stars are discussed.
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Azimuthal Anisotropy of Heavy-Flavor Decay Electrons in p-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2019; 122:072301. [PMID: 30848618 DOI: 10.1103/physrevlett.122.072301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 10/16/2018] [Indexed: 06/09/2023]
Abstract
Angular correlations between heavy-flavor decay electrons and charged particles at midrapidity (|η|<0.8) are measured in p-Pb collisions at sqrt[s_{NN}]=5.02 TeV. The analysis is carried out for the 0%-20% (high) and 60%-100% (low) multiplicity ranges. The jet contribution in the correlation distribution from high-multiplicity events is removed by subtracting the distribution from low-multiplicity events. An azimuthal modulation remains after removing the jet contribution, similar to previous observations in two-particle angular correlation measurements for light-flavor hadrons. A Fourier decomposition of the modulation results in a positive second-order coefficient (v_{2}) for heavy-flavor decay electrons in the transverse momentum interval 1.5<p_{T}<4 GeV/c in high-multiplicity events, with a significance larger than 5σ. The results are compared with those of charged particles at midrapidity and those of inclusive muons at forward rapidity. The v_{2} measurement of open heavy-flavor particles at midrapidity in small collision systems could provide crucial information to help interpret the anisotropies observed in such systems.
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Determination of multiple organochlorine pesticide residues in shrimp using modified QuEChERS extraction and gas chromatography. ACTA ACUST UNITED AC 2018. [DOI: 10.3329/sja.v16i1.37425] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Determination of organochlorine pesticide residues in shrimp is very important to ensure the consumer’s safety and to fulfill the importer’s demand. Therefore, a simple and efficient multiple organochlorine pesticide residues analytical method using quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction technique and Gas Chromatography coupled with Electron Capture Detector (ECD) has been developed and validated for the determination of 19 organochlorine pesticides (α- BHC, δ- BHC, β- BHC, γ- BHC, Heptachlor, Aldrin, Heptachlor Epoxide, γ- Chlordane, α- Chlordane, α- Endosulfan, 4,4 DDE, Dieldrin, Endrin, 4,4 DDD, β- Endosulfan, 4,4 DDT, Endosulfan sulphate, Methoxychlor, and Endrin Ketone) in shrimp. The method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). The average recoveries of the selected pesticides ranged from 84% to 106% with RSDr ≤ 14% in four fortification levels of 0.05, 0.1, 0.2 and 0.3 mg kg-1. The linearity was ≥ 0.996 for all of the selected pesticides with matrix matched calibration standards. The LOD ranged from 0.003 to 0.009 mg kg-1 and the LOQ was 0.05 mg kg-1. This method was applied successfully for the residue analysis of 40 shrimp samples collected from different regions in Bangladesh.SAARC J. Agri., 16(1): 81-93 (2018)
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D-Meson Azimuthal Anisotropy in Midcentral Pb-Pb Collisions at sqrt[s]_{NN}=5.02 TeV. PHYSICAL REVIEW LETTERS 2018; 120:102301. [PMID: 29570314 DOI: 10.1103/physrevlett.120.102301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 11/16/2017] [Indexed: 06/08/2023]
Abstract
The azimuthal anisotropy coefficient v_{2} of prompt D^{0}, D^{+}, D^{*+}, and D_{s}^{+} mesons was measured in midcentral (30%-50% centrality class) Pb-Pb collisions at a center-of-mass energy per nucleon pair sqrt[s_{NN}]=5.02 TeV, with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays at midrapidity, |y|<0.8, in the transverse momentum interval 1<p_{T}<24 GeV/c. The measured D-meson v_{2} has similar values as that of charged pions. The D_{s}^{+} v_{2}, measured for the first time, is found to be compatible with that of nonstrange D mesons. The measurements are compared with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium and have the potential to constrain medium parameters.
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Study of Angiographic Relationship between Peripheral Arterial Diseases with the Involvement of Specific Coronary Artery Lesion. Mymensingh Med J 2018; 27:126-129. [PMID: 29459603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The purpose of this study was to investigate magnitude, pattern and involvement of previously unheralded coronary artery disease in patients suffering from clinically significant peripheral artery disease of lower limbs. This cross sectional study was carried out in National Institute of Cardiovascular Diseases, Dhaka, Bangladesh from January 2014 to February 2015. Total 58 patients with clinically diagnosed peripheral arterial disease of lower limb undergoing angiographic evaluation. Selective CAG in addition to peripheral arteriography was performed in all the study population as per ACC/AHA guidelines for CAG (class IIa recommendation).In this study, it was documented that the proportion of coronary arterial disease was highest in LAD (63.9%) followed by LCX (55.6%), RCA (52.8%), and lowest LM (11.1%) in lesion with aorto-iliac segment. But the proportion of coronary arterial disease was highest in LCX (41.9%) followed by LAD (38.7%), RCA (35.5%), and lowest LM (12.9%) in lesion with femero-popliteal blood vessels. Similarly, the proportion of coronary arterial disease was highest in LCX (36.4%) followed by RCA (27.3%) and equal percentage in LAD and lowest in LM (9.1%) in tibioperoneal segment. Patients of peripheral arterial disease (PAD) having no symptoms of coronary artery disease (CAD) are more likely to have severe coronary artery involvement. Coronary angiogram should be done in patient with PAD to detect previously undetected CAD and pattern of PAD reflects the severity and involvement of coronary arteries.
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J/ψ Elliptic Flow in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2017; 119:242301. [PMID: 29286736 DOI: 10.1103/physrevlett.119.242301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Indexed: 06/07/2023]
Abstract
We report a precise measurement of the J/ψ elliptic flow in Pb-Pb collisions at sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The J/ψ mesons are reconstructed at midrapidity (|y|<0.9) in the dielectron decay channel and at forward rapidity (2.5<y<4.0) in the dimuon channel, both down to zero transverse momentum. At forward rapidity, the elliptic flow v_{2} of the J/ψ is studied as a function of the transverse momentum and centrality. A positive v_{2} is observed in the transverse momentum range 2<p_{T}<8 GeV/c in the three centrality classes studied and confirms with higher statistics our earlier results at sqrt[s_{NN}]=2.76 TeV in semicentral collisions. At midrapidity, the J/ψ v_{2} is investigated as a function of the transverse momentum in semicentral collisions and found to be in agreement with the measurements at forward rapidity. These results are compared to transport model calculations. The comparison supports the idea that at low p_{T} the elliptic flow of the J/ψ originates from the thermalization of charm quarks in the deconfined medium but suggests that additional mechanisms might be missing in the models.
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Anomalous Evolution of the Near-Side Jet Peak Shape in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV. PHYSICAL REVIEW LETTERS 2017; 119:102301. [PMID: 28949169 DOI: 10.1103/physrevlett.119.102301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Indexed: 06/07/2023]
Abstract
The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a p_{T} region inaccessible by direct jet identification. In these measurements pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the shape of the near-side peak formed by particles associated with a higher p_{T} trigger particle (1<p_{T,trig}<8 GeV/c). A combined fit of the near-side peak and long-range correlations is applied to the data allowing the extraction of the centrality evolution of the peak shape in Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV. A significant broadening of the peak in the Δη direction at low p_{T} is found from peripheral to central collisions, which vanishes above 4 GeV/c, while in the Δφ direction the peak is almost independent of centrality. For the 10% most central collisions and 1<p_{T,assoc}<2 GeV/c, 1<p_{T,trig}<3 GeV/c a novel feature is observed: a depletion develops around the center of the peak. The results are compared to pp collisions at the same center of mass energy and ampt model simulations. The comparison to the investigated models suggests that the broadening and the development of the depletion is connected to the strength of radial and longitudinal flow.
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Flow Dominance and Factorization of Transverse Momentum Correlations in Pb-Pb Collisions at the LHC. PHYSICAL REVIEW LETTERS 2017; 118:162302. [PMID: 28474923 DOI: 10.1103/physrevlett.118.162302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Indexed: 06/07/2023]
Abstract
We present the first measurement of the two-particle transverse momentum differential correlation function, P_{2}≡⟨Δp_{T}Δp_{T}⟩/⟨p_{T}⟩^{2}, in Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV. Results for P_{2} are reported as a function of the relative pseudorapidity (Δη) and azimuthal angle (Δφ) between two particles for different collision centralities. The Δϕ dependence is found to be largely independent of Δη for |Δη|≥0.9. In the 5% most central Pb-Pb collisions, the two-particle transverse momentum correlation function exhibits a clear double-hump structure around Δφ=π (i.e., on the away side), which is not observed in number correlations in the same centrality range, and thus provides an indication of the dominance of triangular flow in this collision centrality. Fourier decompositions of P_{2}, studied as a function of the collision centrality, show that correlations at |Δη|≥0.9 can be well reproduced by a flow ansatz based on the notion that measured transverse momentum correlations are strictly determined by the collective motion of the system.
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Correlated Event-by-Event Fluctuations of Flow Harmonics in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV. PHYSICAL REVIEW LETTERS 2016; 117:182301. [PMID: 27835023 DOI: 10.1103/physrevlett.117.182301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Indexed: 06/06/2023]
Abstract
We report the measurements of correlations between event-by-event fluctuations of amplitudes of anisotropic flow harmonics in nucleus-nucleus collisions, obtained for the first time using a new analysis method based on multiparticle cumulants in mixed harmonics. This novel method is robust against systematic biases originating from nonflow effects and by construction any dependence on symmetry planes is eliminated. We demonstrate that correlations of flow harmonics exhibit a better sensitivity to medium properties than the individual flow harmonics. The new measurements are performed in Pb-Pb collisions at the center-of-mass energy per nucleon pair of sqrt[s_{NN}]=2.76 TeV by the ALICE experiment at the Large Hadron Collider. The centrality dependence of correlation between event-by-event fluctuations of the elliptic v_{2} and quadrangular v_{4} flow harmonics, as well as of anticorrelation between v_{2} and triangular v_{3} flow harmonics are presented. The results cover two different regimes of the initial state configurations: geometry dominated (in midcentral collisions) and fluctuation dominated (in the most central collisions). Comparisons are made to predictions from Monte Carlo Glauber, viscous hydrodynamics, ampt, and hijing models. Together with the existing measurements of the individual flow harmonics the presented results provide further constraints on the initial conditions and the transport properties of the system produced in heavy-ion collisions.
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Effect of storage duration on the stored pupae of parasitoid Bracon hebetor (Say) and its impact on parasitoid quality. ACTA ACUST UNITED AC 2016. [DOI: 10.3329/bjar.v41i2.28232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The ecto-endo larval parasitoid, Bracon hebetor (Say) is an important biocontrol agent. Effective storage methods for B. hebetor are essential for raising its success as a commercial bio-control agent against lepidopteran pests. The study was undertaken to determine the effect of storage duration on the pupae of Bracon hebetor in terms of pupal survival, adult emergence, percent parasitism, female and male longevity, female fecundity and sex ratio. Three to four days old pupae were stored for 0, 1, 2, 3, 4, 5, 6, 7 and 8 weeks at 4 ± 1oC. The ranges of time for adult emergence from stored pupae, production of total adult, survivability of pupae, parasitism of host larvae by the parasitoid, longevity of adult female and male and fecundity were 63.0 -7.5 days, 6.8-43.8/50 host larvae, 13.0-99.5%, 0.0 -97.5%, 0.00-20.75 days, 0.00-17.25 days and 0.00- 73.00/50 female, respectively. The time of adult emergence and mortality of pupae increased but total number of adult emergence, survivability of pupae, longevity of adult female and male decreased gradually with the progress of storage period of B. hebetor pupae. The prevalence of male was always higher than that of female. Therefore, short-term storage of B. hebetor pupae could be stored for up to 4 weeks without disturbing the functioning of the parasitoid. It is important for sustaining and accumulating large numbers of parasitoids in mass rearing programs and subsequent use of field application.Bangladesh J. Agril. Res. 41(2): 297-310, June 2016
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Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2016; 116:222302. [PMID: 27314715 DOI: 10.1103/physrevlett.116.222302] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Indexed: 06/06/2023]
Abstract
The pseudorapidity density of charged particles, dN_{ch}/dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02 TeV. For the 5% most central collisions, we measure a value of 1943±54. The rise in dN_{ch}/dη as a function of sqrt[s_{NN}] is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dN_{ch}/dη as a function of the average number of participant nucleons, ⟨N_{part}⟩, calculated in a Glauber model, is compared with the previous measurement at sqrt[s_{NN}]=2.76 TeV. A constant factor of about 1.2 describes the increase in dN_{ch}/dη from sqrt[s_{NN}]=2.76 to 5.02 TeV for all centrality classes, within the measured range of 0%-80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.
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Measurement of an Excess in the Yield of J/ψ at Very Low p_{T} in Pb-Pb Collisions at sqrt[s]_{NN}=2.76 TeV. PHYSICAL REVIEW LETTERS 2016; 116:222301. [PMID: 27314714 DOI: 10.1103/physrevlett.116.222301] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Indexed: 06/06/2023]
Abstract
We report on the first measurement of an excess in the yield of J/ψ at very low transverse momentum (p_{T}<0.3 GeV/c) in peripheral hadronic Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV, performed by ALICE at the CERN LHC. Remarkably, the measured nuclear modification factor of J/ψ in the rapidity range 2.5<y<4 reaches about 7 (2) in the p_{T} range 0-0.3 GeV/c in the 70%-90% (50%-70%) centrality class. The J/ψ production cross section associated with the observed excess is obtained under the hypothesis that coherent photoproduction of J/ψ is the underlying physics mechanism. If confirmed, the observation of J/ψ coherent photoproduction in Pb-Pb collisions at impact parameters smaller than twice the nuclear radius opens new theoretical and experimental challenges and opportunities. In particular, coherent photoproduction accompanying hadronic collisions may provide insight into the dynamics of photoproduction and nuclear reactions, as well as become a novel probe of the quark-gluon plasma.
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Anisotropic Flow of Charged Particles in Pb-Pb Collisions at √[s{NN}]=5.02 TeV. PHYSICAL REVIEW LETTERS 2016; 116:132302. [PMID: 27081971 DOI: 10.1103/physrevlett.116.132302] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 06/05/2023]
Abstract
We report the first results of elliptic (v_{2}), triangular (v_{3}), and quadrangular (v_{4}) flow of charged particles in Pb-Pb collisions at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurements are performed in the central pseudorapidity region |η|<0.8 and for the transverse momentum range 0.2<p_{T}<5 GeV/c. The anisotropic flow is measured using two-particle correlations with a pseudorapidity gap greater than one unit and with the multiparticle cumulant method. Compared to results from Pb-Pb collisions at sqrt[s_{NN}]=2.76 TeV, the anisotropic flow coefficients v_{2}, v_{3}, and v_{4} are found to increase by (3.0±0.6)%, (4.3±1.4)%, and (10.2±3.8)%, respectively, in the centrality range 0%-50%. This increase can be attributed mostly to an increase of the average transverse momentum between the two energies. The measurements are found to be compatible with hydrodynamic model calculations. This comparison provides a unique opportunity to test the validity of the hydrodynamic picture and the power to further discriminate between various possibilities for the temperature dependence of shear viscosity to entropy density ratio of the produced matter in heavy-ion collisions at the highest energies.
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A Rapid and Reliable End-To-End Anastomosis Technique for Emergency Vascular Surgery--A Case Report. Mymensingh Med J 2016; 25:158-160. [PMID: 26931267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A 28 year old male presented to us with 8 hours old open fracture of distal shaft of left femur which was already stabilized with external fixator but had no palpable distal pulse both clinically and on doppler examination. He underwent a primary repair following limited segmental resection. Commonly end-to-end anastomosis techniques following transection of arteries include interrupted and continuous suturing with or without 'parachuting' of the vessel or graft. Here we offer a rapid and reliable technique with following advantages: i) operating system always towards the surgeon, ii) posterior row of suture placed as both ends are well visualized, iii) less chance of catching posterior wall, iv) flushing performed easily before completing anterior row suture. Upto 2nd post operative day anticoagulant used in the form of inj. Heparin 2500 IU subcutaneously 8 hourly and patient was discharged from hospital on 3rd post operative day with presence of good distal pulses both on clinical and Doppler examination. Fourteen days later, on follow up Duplex study showed normal arterial flow without any stenosis or occlusion.
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Measurement of pion, kaon and proton production in proton-proton collisions at [Formula: see text] TeV. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2015; 75:226. [PMID: 26041975 PMCID: PMC4446008 DOI: 10.1140/epjc/s10052-015-3422-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 04/20/2015] [Indexed: 05/14/2023]
Abstract
The measurement of primary [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] production at mid-rapidity ([Formula: see text] 0.5) in proton-proton collisions at [Formula: see text][Formula: see text] 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/[Formula: see text] for pions, from 0.2 up to 6 GeV/[Formula: see text] for kaons and from 0.3 up to 6 GeV/[Formula: see text] for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.
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Exclusive J/ψ photoproduction off protons in ultraperipheral p-Pb collisions at √(s(NN))=5.02 TeV. PHYSICAL REVIEW LETTERS 2014; 113:232504. [PMID: 25526123 DOI: 10.1103/physrevlett.113.232504] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Indexed: 06/04/2023]
Abstract
We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sqrt[s_{NN}]=5.02 TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5<y<4 (p-Pb) or -3.6<y<-2.6 (Pb-p), and no other particles observed in the ALICE acceptance. The measured cross sections σ(γ+p→J/ψ+p) are 33.2±2.2(stat)±3.2(syst)±0.7(theor) nb in p-Pb and 284±36(stat)_{-32}^{+27}(syst)±26(theor) nb in Pb-p collisions. We measure this process up to about 700 GeV in the γp center of mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the J/ψ photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2×10^{-2} and ∼2×10^{-5}, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.
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Measurement of prompt D-meson production in p-Pb collisions at √(s(NN))=5.02 TeV. PHYSICAL REVIEW LETTERS 2014; 113:232301. [PMID: 25526119 DOI: 10.1103/physrevlett.113.232301] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Indexed: 06/04/2023]
Abstract
The p_{T}-differential production cross sections of the prompt charmed mesons D^{0}, D^{+}, D^{*+}, and D_{s}^{+} and their charge conjugate in the rapidity interval -0.96<y_{cms}<0.04 were measured in p-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The nuclear modification factor R_{pPb}, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%-20% uncertainties with unity in the transverse momentum interval 1<p_{T}<24 GeV/c. No significant difference among the R_{pPb} of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.
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Abstract
BACKGROUND AND AIMS The intestinal microbiota plays a critical role in maintaining human health; however, the mechanisms governing the normal homeostatic number and composition of these microbes are largely unknown. Previously it was shown that intestinal alkaline phosphatase (IAP), a small intestinal brush border enzyme, functions as a gut mucosal defence factor limiting the translocation of gut bacteria to mesenteric lymph nodes. In this study the role of IAP in the preservation of the normal homeostasis of the gut microbiota was investigated. METHODS Bacterial culture was performed in aerobic and anaerobic conditions to quantify the number of bacteria in the stools of wild-type (WT) and IAP knockout (IAP-KO) C57BL/6 mice. Terminal restriction fragment length polymorphism, phylogenetic analyses and quantitative real-time PCR of subphylum-specific bacterial 16S rRNA genes were used to determine the compositional profiles of microbiotas. Oral supplementation of calf IAP (cIAP) was used to determine its effects on the recovery of commensal gut microbiota after antibiotic treatment and also on the colonisation of pathogenic bacteria. RESULTS IAP-KO mice had dramatically fewer and also different types of aerobic and anaerobic microbes in their stools compared with WT mice. Oral supplementation of IAP favoured the growth of commensal bacteria, enhanced restoration of gut microbiota lost due to antibiotic treatment and inhibited the growth of a pathogenic bacterium (Salmonella typhimurium). CONCLUSIONS IAP is involved in the maintenance of normal gut microbial homeostasis and may have therapeutic potential against dysbiosis and pathogenic infections.
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PCR-based detection and partial genome sequencing indicate high genetic diversity in Bangladeshi begomoviruses and their whitefly vector, Bemisia tabaci. Virus Genes 2006; 34:373-85. [PMID: 16927121 DOI: 10.1007/s11262-006-0027-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 06/19/2006] [Indexed: 11/26/2022]
Abstract
The population diversity of Bangladeshi begomoviruses and their vector, Bemisia tabaci was analysed by PCR-based detection and partial genome sequencing. B. tabaci adults and plants expressing symptoms of virus infection were collected from locations representing diverse agro-ecological regions of the country. Universal and species-specific primers were used to detect begomoviruses in seven crops (chilli, okra, papaya, pumpkin, sponge gourd, tomato and yardlong bean) and two common weeds (Ageratum conyzoides and Croton bonplandianum). At least five distinct species of tomato leaf curl viruses infected tomato and other host-plants. Phylogenetic analyses of their nucleotide sequences ( approximately 530 bases) from the intergenic region and capsid protein of DNA-A indicated the existence of five distinct clusters of begomoviruses. Begomoviruses infecting tomato, chilli and dolichos have been reported previously, and those infecting Ageratum, Croton, okra, papaya, pumpkin and yardlong bean are described for the first time. Phylogenetic analyses based on mitochondrial cytochrome oxidase I gene sequences of 21 B. tabaci from Bangladesh and other reference sequences grouped them into at least two independent clusters. Some sequences from different countries, e.g., Bangladesh, China, India, Nepal, Pakistan and Thailand were almost identical while others collected from plants within the same field diverged by as much as 15%, indicating high diversity even at the local level. None of the B. tabaci from Bangladesh grouped with the reference B- and Q-biotype sequences, thus these two aggressive biotypes were apparently absent from Bangladesh.
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Development of mass trapping technique for control of brinjal shoot and fruit borer, Leucinodes orbonalis (Lepidoptera: Pyralidae). BULLETIN OF ENTOMOLOGICAL RESEARCH 2005; 95:589-96. [PMID: 16336706 DOI: 10.1079/ber2005389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Locally-produced clear plastic water traps (12 cm x 14 cm base and 21 cm height) were optimized for use in large-scale mass trapping trials for control of brinjal fruit and shoot borer, Leucinodes orbonalis Guenée. Changing the shape (square and triangular) and number (two and four) of entry holes in the water trap had no significant effect on trap catch. Significantly more male moths were caught in traps treated with water containing powdered detergent than liquid detergent, light gear oil or insecticide. All water traps tested caught significantly higher numbers of moths than sticky delta traps with open sides under farmers' field conditions. Trap catches per 100 m2 were found to increase with increasing number of traps from 3 to 6 but the difference in catch between 4 and 6 traps per 100 m2 was not significant. Two small-scale replicated integrated pest management (IPM) trials were conducted consisting of the optimized water trap placed out with 10 m spacing (4 per 100 m2) and infested shoots pruned and destroyed. The first season trial had two treatments, IPM and farmers' practice in which farmers applied insecticide every two days in the peak harvest period. Overall, the percentage of healthy fruit and yields in both treatments were comparable at 53.8 and 49.6% and 20 and 19.4 tonnes per ha in the IPM and farmers' practice plots respectively. However, the initial infestations in the IPM plots (68%) were significantly higher than in farmers' practice plots (16%) due to the proximity of the nurseries used for the IPM plots to stacks of brinjal crop residues from the previous season that acted as a source of infestation. The second season's trials contained a third treatment in which IPM and farmers' practice were combined. The percent total healthy fruits harvested were 46.1, 58.6 and 69.1% respectively for the farmers' practice, farmers' practice plus IPM and IPM alone. Averaged total fruit yields were approximately 12 tonnes per ha for the farmers' practice plots and 30 tonnes per ha for each of the IPM-treated plots. The IPM plot had significantly fewer infested fruit than the IPM plus farmers practice plots and this was attributed to the activity of the larval parasitoid Trathala flavo-orbitalis (Cameron) that was suppressed in trial plots treated with insecticides.
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Nucleotide sequencing, whitefly transmission, and screening tomato for resistance against two newly described begomoviruses in bangladesh. PHYTOPATHOLOGY 2005; 95:1472-1481. [PMID: 18943559 DOI: 10.1094/phyto-95-1472] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
ABSTRACT The molecular diversity of Tomato leaf curl viruses (ToLCVs), from the two main tomato growing areas of Jessore and Joydebpur, Bangladesh, was investigated. The viral DNA was amplified from tomato plants exhibiting mild and severe symptoms by polymerase chain reaction, and the complete genomes of the ToLCVs were sequenced. An isolate of the bipartite Tomato leaf curl New Delhi virus-Severe (ToLCNDV-Svr) was associated with the severe symptom phenotype from Jessore (ToLCNDV-Svr[Jes]). A previously undescribed monopartite virus, designated Tomato leaf curl Joydebpur virus-Mild (ToLCJV-Mld), was sequenced from plants showing mild symptoms. ToLCNDV-Svr[Jes] was most closely related to ToLCNDV-[Lucknow] at 95.7% nucleotide (nt) identity and Tomato leaf curl Gujarat virus-[Varanasi] at 90.6% nt identity, based on DNA-A and -B component sequences. ToLCJV-Mld was similar to Pepper leaf curl Bangladesh virus at 87.1% DNA-A nt identity. Identification of ToLCNDV-Svr[Jes] and ToLCJV-Mld was in addition to the previously described Tomato leaf curl Bangladesh virus, with which they shared 73.2 and 86.0% DNA-A nt identities, thus demonstrating the existence of at least three distinct viruses infecting tomato in Bangladesh. Nucleotide identities and placement in phylogenetic trees suggested that the three ToLCVs may have had different evolutionary pathways. The whitefly, Bemisia tabaci, transmitted the viruses of this study equally efficiently. Four tomato cultivars (TLB111, TLB130, TLB133, and TLB182) resistant/ tolerant to South Indian ToLCV were screened against the Bangladesh ToLCVs in 2003-04. Although challenged by diverse viruses and potentially mixed infections, disease incidence remained low (6 to 45%) in the resistant cultivars compared with local cultivars (68 to 100%).
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First Report of Tomato leaf curl New Delhi virus Infecting Tomato in Bangladesh. PLANT DISEASE 2005; 89:1011. [PMID: 30786642 DOI: 10.1094/pd-89-1011c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tomato is an important cash crop for resource-poor farmers and accounts for 20% of the 2 million t of vegetables grown annually in Bangladesh. Tomato cultivation is affected by Tomato leaf curl virus (ToLCV), which can cause as much as 100% yield loss. Plants exhibiting typical ToLCV disease symptoms of yellowing, severe leaf curling, and stunting were collected at Jessore, Bangladesh during September 2003. The putative virus was transmitted from tomato to tomato by the whitefly Bemisia tabaci. In two separate experiments, 100% transmission was achieved by using 10 viruliferous B. tabaci adults for each of the 20 test plants that was confirmed by comparing the symptoms on test and virus source plants. Total DNAs were extracted from the symptomatic leaves, and the putative viral genomes were amplified by polymerase chain reaction by using the Deng A and B primers (1). Sequences generated from these primers were used to design virus-specific primers that were used to obtain complete viral sequences. Full-length DNA-A (2,740 nt; GenBank Accession No. AJ875157) and DNA-B (2,688 nt; GenBank Accession No. AJ875158) sequences of a bipartite Tomato leaf curl New Delhi virus from Jessore (ToLCNDV-[Jes]) were obtained, which were most similar to the corresponding sequences of ToLCNDV-(Lucknow) (GenBank Accession No. Y16421) at 95.7% and Tomato leaf curl Gujarat virus-(Varanasi) (Gen-Bank Accession No. AY190291) at 90.6% nt identities, respectively. DNA-A sequences had only 73.2% nt identity with the previously reported monopartite Tomato leaf curl Bangladesh virus (GenBank Accession No. AF188481) (2), confirming the occurrence of mono- and bipartite bego-moviruses in Bangladesh. The virus diversity poses a challenge for ToLCVD management in Bangladesh. References: (1) D. Deng et al. Ann. Appl. Biol. 125:327, 1994. (2) S. K. Green et al. Plant Dis. 85:1286, 2001.
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Female sex pheromone of brinjal fruit and shoot borer, Leucinodes orbonalis (Lepidoptera: Pyralidae): trap optimization and application in IPM trials. BULLETIN OF ENTOMOLOGICAL RESEARCH 2003; 93:107-113. [PMID: 12699531 DOI: 10.1079/ber2002220] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Delta and wing traps baited with synthetic female sex pheromone of Leucinodes orbonalis Guenée were found to catch and retain ten times more moths than either Spodoptera or uni-trap designs. Locally-produced water and funnel traps were as effective as delta traps, although 'windows' cut in the side panels of delta traps significantly increased trap catch from 0.4 to 2.3 moths per trap per night. Trap catch was found to be proportional to the radius of sticky disc traps in the range 5-20 cm radius, discs with a 2.5 cm radius caught no moths. Wing traps placed at crop height caught significantly more moths than traps placed 0.5 m above or below the crop canopy. Replicated integrated pest management (IPM) trials (3 x 0.5 ha per treatment) were conducted in farmers fields with young and mature eggplant crops. Farmers applied insecticides at least three times a week in all check and IPM plots. In addition pheromone traps were placed out at a density of 100 per ha and infested shoots removed weekly in the 0.5 ha IPM plots. Pheromone trap catches were reduced significantly from 2.0 to 0.4 moths per trap per night respectively in check and IPM plots in a young crop and 1.1 to 0.3 moths per trap per night in check and IPM plots respectively in a mature crop. Fruit damage was significantly reduced from an average of 41.8% and 51.2% in check plots of young and mature crops respectively to 22% and 26.4 respectively in the associated IPM plots. Significant differences in pheromone trap catches and fruit damage were attained four and two weeks respectively after IPM treatments began in the mature crop whereas in the immature crop significant differences were not observed for the first eight to nine weeks respectively. The relative impact of removing infested shoots and mass trapping on L. orbonalis larval populations was not established in these trials but in both cases there was an estimated increase of approximately 50% in marketable fruit obtained by the combination of control techniques compared to insecticide treatment alone.
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Abstract
The brinjal fruit and shoot borer, Leucinodes orbonalis is the major pest of eggplant in South Asia. Analysis of female pheromone gland extracts prepared from insects of Indian and Taiwanese origin confirmed (E)-11-hexadecenyl acetate (E11-16:Ac) as the major pheromone component with 0.8 to 2.8% of the related (E)-11-hexadecen-1-ol (E11-16:OH), as previously reported from Sri Lanka. The average quantity of E11-16:Ac extracted per female was estimated to be 33 ng, with a range of 18.9 to 46.4 ng when collected 2 to 3 hr into the scotophase. In field trials conducted in India, blends containing between 1 and 10% E11-16:OH caught more male L. orbonalis than E11-16:Ac alone. At the 1,000 microg dose, on white rubber septa, addition of 1% E11-16:OH to E11-16:Ac was found to be more attractive to male L. orbonalis than either 0.1 or 10% E11-16:OH. Trap catch was found to be positively correlated with pheromone release rate, with the highest dose tested, 3,000 microg, on white rubber septa catching more male moths than lower doses. Field and wind tunnel release rate studies confirmed that E11-16:OH released from white rubber septa and polyethylene vials at approximately twice the rate of E11-16:Ac and that the release rate of both compounds was doubled in polyethylene vials compared to white rubber septa. This difference in release rate was reflected in field trials conducted in Bangladesh where polyethylene vial dispensers caught more male moths than either black or white rubber septa, each loaded with the same 100:1 blend of E11-16:Ac and E11-16:OH in a 3,000 microg loading.
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Diethylstilbestrol: a review of its toxicity and use as a growth promotant in food-producing animals. JOURNAL OF ENVIRONMENTAL PATHOLOGY AND TOXICOLOGY 1978; 1:279-313. [PMID: 363962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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The labeling of polysomes and rough microsomal membranes by 5-fluoroorotic acid. Biochem Biophys Res Commun 1977; 74:1441-9. [PMID: 843370 DOI: 10.1016/0006-291x(77)90603-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
Following a concomitant oral dose of salicylamide and acetaminophen (5 mg/kg of each) the urinary excretion of glucuronide and sulfate conjugates of the drugs were followed in children (ages seven to ten years) and adults. No significant difference were observed between the two age groups in the half-lives for appearance of salicylamide conjugates in urine. Age-related changes in the metabolic pathways, however, were observed. The mean percentage of dose excreted as salicylamide sulfate was significantly higher in children (78%) than in adults (36%). In contrast, salicylamide glucuronide was the major excretory product in adults. Similar age-related differences were observed for acetaminophen conjugation. Pharmacokinetic analysis indicated that the deficiency in glucuronide conjugation of these drugs in children is accompanied by a higher rate of sulfate formation.
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N6-(delta 2-isopentenyl)adenosine: its conversion to inosine, catalyzed by adenosine aminohydrolases from chicken bone marrow and calf intestinal mucosa. CANADIAN JOURNAL OF BIOCHEMISTRY 1971; 49:623-30. [PMID: 5315139 DOI: 10.1139/o71-089] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
N6-(Δ2-Isopentenyl)adenosine, a component of tRNA, displays biological activity in both plant and animal systems. As part of a study of the biological behavior of this nucleoside, its degradation in animal tissues has been studied. An enzyme that catalyzes conversion of this nucleoside to inosine has been partially purified from chicken bone marrow. The enzyme preparation also catalyzes conversion of adenosine to inosine at about 40 times the rate of conversion of N6-(Δ2-isopentenyl)adenosine. A series of analogues of this nucleoside has been tested as substrates. The Δ3-isomer, n-pentyl, isopentyl, and furfuryl derivatives are readily cleaved. Hydroxylated derivatives of the Δ2-isopentenyl side chain, however, do not serve as substrates. Adenosine aminohydrolase from calf intestinal mucosa also catalyzes conversion of N6-(Δ2-isopentenyl)adenosine to inosine, although in order to obtain a measurable rate, the concentration of enzyme must be about 1000 times that needed to catalyze conversion of adenosine.
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Physiological activity of derivatives of a modified component of transfer RNA, N-(nebularin-6-ylcarbamoyl)-L-threonine. Cancer Res 1971; 31:704-5. [PMID: 5104166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Separation of the delta-2 and delta-3 isomers of N6-(delta-2-isopentenyl)adenosine by gas chromatography and characterization by mass spectroscopy. Anal Biochem 1971; 40:424-8. [PMID: 5551552 DOI: 10.1016/0003-2697(71)90402-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Abstract
By use of a radioactive labeling technique N-(nebularin-6-ylcarbamoyl)threonine has been detected in plant transfer RNA. Derivatives of this nucleoside promote cell division of a cytokinin-requiring soya bean tissue.
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Studies on deoxyribonucleoproteins. VII. Purification of deoxyribonucleoproteins by carrier-free continuous electrophoresis. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 209:550-8. [PMID: 5456730 DOI: 10.1016/0005-2787(70)90752-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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