Tests of Lepton Universality Using B^{0}→K_{S}^{0}ℓ^{+}ℓ^{-} and B^{+}→K^{*+}ℓ^{+}ℓ^{-} Decays

Tests of lepton universality in B^{0}→K_{S}^{0}ℓ^{+}ℓ^{-} and B^{+}→K^{*+}ℓ^{+}ℓ^{-} decays where ℓ is either an electron or a muon are presented. The differential branching fractions of B^{0}→K_{S}^{0}e^{+}e^{-} and B^{+}→K^{*+}e^{+}e^{-} decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9  fb^{-1} . The results are consistent with the standard model and previous tests of lepton universality in related decay modes. The first observation of B^{0}→K_{S}^{0}e^{+}e^{-} and B^{+}→K^{*+}e^{+}e^{-} decays is reported.

Observation of the Decay Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ}

The first observation of the semileptonic b-baryon decay Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ}, with a significance of 6.1σ, is reported using a data sample corresponding to 3  fb^{-1} of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ^{-} lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ})/B(Λ_{b}^{0}→Λ_{c}^{+}π^{-}π^{+}π^{-}) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ})=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λ_{b}^{0}→Λ_{c}^{+}π^{-}π^{+}π^{-}. The ratio of semileptonic branching fractions R(Λ_{c}^{+})≡B(Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ})/B(Λ_{b}^{0}→Λ_{c}^{+}μ^{-}ν[over ¯]_{μ}) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λ_{b}^{0}→Λ_{c}^{+}μ^{-}ν[over ¯]_{μ} contributes to the last term. This result is in agreement with the standard model prediction.

Observation of Two New Excited Ξ_{b}^{0} States Decaying to Λ_{b}^{0}K^{-}π^{+}

Two narrow resonant states are observed in the Λ_{b}^{0}K^{-}π^{+} mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6  fb^{-1}. The minimal quark content of the Λ_{b}^{0}K^{-}π^{+} system indicates that these are excited Ξ_{b}^{0} baryons. The masses of the Ξ_{b}(6327)^{0} and Ξ_{b}(6333)^{0} states are m[Ξ_{b}(6327)^{0}]=6327.28_{-0.21}^{+0.23}±0.12±0.24 and m[Ξ_{b}(6333)^{0}]=6332.69_{-0.18}^{+0.17}±0.03±0.22  MeV, respectively, with a mass splitting of Δm=5.41_{-0.27}^{+0.26}±0.12  MeV, where the uncertainties are statistical, systematic, and due to the Λ_{b}^{0} mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ[Ξ_{b}(6327)^{0}]<2.20(2.56) and Γ[Ξ_{b}(6333)^{0}]<1.60(1.92)  MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξ_{b}^{0} resonances.

Measurement of the Nuclear Modification Factor and Prompt Charged Particle Production in p-Pb and pp Collisions at sqrt[s_{NN}]=5 TeV

The production of prompt charged particles in proton-lead collisions and in proton-proton collisions at the nucleon-nucleon center-of-mass energy sqrt[s_{NN}]=5  TeV is studied at LHCb as a function of pseudorapidity (η) and transverse momentum (p_{T}) with respect to the proton beam direction. The nuclear modification factor for charged particles is determined as a function of η between -4.8<η<-2.5 (backward region) and 2.0<η<4.8 (forward region), and p_{T} between 0.2<p_{T}<8.0  GeV/c. The results show a suppression of charged particle production in proton-lead collisions relative to proton-proton collisions in the forward region and an enhancement in the backward region for p_{T} larger than 1.5  GeV/c. This measurement constrains nuclear PDFs and saturation models at previously unexplored values of the parton momentum fraction down to 10^{-6}.

Probing the Gluonic Structure of the Deuteron with J/ψ Photoproduction in d+Au Ultraperipheral Collisions

Understanding gluon density distributions and how they are modified in nuclei are among the most important goals in nuclear physics. In recent years, diffractive vector meson production measured in ultraperipheral collisions (UPCs) at heavy-ion colliders has provided a new tool for probing the gluon density. In this Letter, we report the first measurement of J/ψ photoproduction off the deuteron in UPCs at the center-of-mass energy sqrt[s_{NN}]=200  GeV in d+Au collisions. The differential cross section as a function of momentum transfer -t is measured. In addition, data with a neutron tagged in the deuteron-going zero-degree calorimeter is investigated for the first time, which is found to be consistent with the expectation of incoherent diffractive scattering at low momentum transfer. Theoretical predictions based on the color glass condensate saturation model and the leading twist approximation nuclear shadowing model are compared with the data quantitatively. A better agreement with the saturation model has been observed. With the current measurement, the results are found to be directly sensitive to the gluon density distribution of the deuteron and the deuteron breakup process, which provides insights into the nuclear gluonic structure.

Search for the Chiral Magnetic Effect via Charge-Dependent Azimuthal Correlations Relative to Spectator and Participant Planes in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in midcentral (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.

Study of Z Bosons Produced in Association with Charm in the Forward Region

Events containing a Z boson and a charm jet are studied for the first time in the forward region of proton-proton collisions. The data sample used corresponds to an integrated luminosity of 6  fb^{-1} collected at a center-of-mass energy of 13 TeV with the LHCb detector. In events with a Z boson and a jet, the fraction of charm jets is determined in intervals of Z-boson rapidity in the range 2.0<y(Z)<4.5. A sizable enhancement is observed in the forwardmost y(Z) interval, which could be indicative of a valencelike intrinsic-charm component in the proton wave function.

[Efficacy and safety of endothelin receptor antagonists combined with phosphodiesterase 5 inhibitor in the treatment of pulmonary arterial hypertension: a network meta-analysis]

Objective: To examine the efficacy and safety of endothelin receptor antagonists (ERA) combined with phosphodiesterase 5 inhibitors (PDE5i) in the treatment of pulmonary artery hypertension (PAH). Methods: Computer-based retrieval was performed on PubMed, Cochrane Library, CNKI, Wanfang, and VIP database (up to February 12th, 2021). Randomized controlled trials about endothelin receptor antagonists (ERAs) or PDE5i in patients with PAH were collected. The change of 6-minute walking distance (6MWD) in 12-16 weeks was used as primary outcome index. Case fatality rate, worsening clinical events, WHO functional class (FC) improvement, adverse events (AEs), serious adverse events (SAE) were the key secondary outcomes indicators. STATA 16.0 software was used for network meta-analysis, and the pooled estimates of odds ratios (ORs) or weighted mean differences (WMDs) and 95% confidence intervals (CIs) of the results were shown. To help explain ORs and WMDs, we used the surface under the cumulative ranking curve (SUCRA) to calculate the probability of each intervention. Results: We included 29 trials with 5 949 participants. In network meta-analysis, Bosentan combined with Sildenafil (WMD=53.93, 95%CI=6.19-101.66) had shown the greatest improvement in 6MWD compared with placebo, followed by Bosentan combined with Tadalafil (WMD=50.84, 95%CI=7.05-94.62), Ambrisentan combined with Tadalafil (WMD=46.67, 95%CI=15.88-77.45), Bosentan (WMD=29.44, 95%CI=5.86-53.02), Ambrisentan (WMD=23.90, 95%CI=0.31-47.48) and Macitentan (WMD=21.57, 95%CI=2.45-40.69). According to SUCRA, the effects of different intervention measures on improving 6MWD in patients with arterial pulmonary hypertension were as follows: Bosentan+Sildenafil (82.9%)>Bosentan+Tadalafil (78.4%)>Ambrisentan+Tadalafil (77.1%)>Bosentan (49.2%)>Sildenafil (48.5%)>Ambrisentan (40.3%)>Macitentan (37.3%)>Tadalafil (33.0%)>Placebo (3.3%). For the WHO functional class, Sildenafil (OR=2.90, 95%CI=1.04-8.08) was optimal compared with placebo, followed by Bosentan (OR=2.15, 95%CI=1.15-4.04), and there was no significant difference in the rest. For clinical worsening, Bosentan combined with Tadalafil (OR=0.08, 95%CI=0.01-0.49) performed best compared with placebo, followed by Bosentan (OR=0.20, 95%CI=0.11-0.38), Bosentan combined with Sildenafil (OR=0.21, 95%CI=0.09-0.46), Ambrisentan combined with Tadalafil (OR=0.27, 95%CI=0.15-0.50), Sildenafil (OR=0.33, 95%CI=0.17-0.66) and Tadalafil (OR=0.44, 95%CI=0.21-0.90). There was no statistical difference between all interventions and placebo in terms of the incidence of adverse events and serious adverse events. For case fatality rate, Ambrisentan (OR=0.28, 95%CI=0.11-0.74) was statistically superior to placebo and there was no statistics difference in the rest. Conclusions: The combination therapy of ERAs and PDE5i performed well in the short-term improvement of motor function. Furthermore, there was no significant difference with monotherapy in terms of safety. However, it is worth emphasizing that the choice of treatment should be based on the patient's individualized situation and the patient's requirements.

Evidence for a New Structure in the J/ψp and J/ψp[over ¯] Systems in B_{s}^{0}→J/ψpp[over ¯] Decays

An amplitude analysis of flavor-untagged B_{s}^{0}→J/ψpp[over ¯] decays is performed using a sample of 797±31 decays reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity of 9  fb^{-1}. Evidence for a new structure in the J/ψp and J/ψp[over ¯] systems with a mass of 4337_{-4}^{+7} _{-2}^{+2}  MeV and a width of 29_{-12}^{+26} _{-14}^{+14}  MeV is found, where the first uncertainty is statistical and the second systematic, with a significance in the range of 3.1 to 3.7σ, depending on the assigned J^{P} hypothesis.

Analysis of Neutral B-Meson Decays into Two Muons

Branching fraction and effective lifetime measurements of the rare decay B_{s}^{0}→μ^{+}μ^{-} and searches for the decays B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ are reported using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a luminosity of 9  fb^{-1}. The branching fraction B(B_{s}^{0}→μ^{+}μ^{-})=(3.09_{-0.43-0.11}^{+0.46+0.15})×10^{-9} and the effective lifetime τ(B_{s}^{0}→μ^{+}μ^{-})=2.07±0.29±0.03  ps are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ decays is found and upper limits B(B^{0}→μ^{+}μ^{-})<2.6×10^{-10} and B(B_{s}^{0}→μ^{+}μ^{-}γ)<2.0×10^{-9} at the 95% C.L. are determined, where the latter is limited to the range m_{μμ}>4.9  GeV/c^{2}. The results are in agreement with the standard model expectations.

Measurement of the Sixth-Order Cumulant of Net-Proton Multiplicity Distributions in Au+Au Collisions at sqrt[s_{NN}]=27, 54.4, and 200 GeV at RHIC

According to first-principle lattice QCD calculations, the transition from quark-gluon plasma to hadronic matter is a smooth crossover in the region μ_{B}≤T_{c}. In this range the ratio, C_{6}/C_{2}, of net-baryon distributions are predicted to be negative. In this Letter, we report the first measurement of the midrapidity net-proton C_{6}/C_{2} from 27, 54.4, and 200 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). The dependence on collision centrality and kinematic acceptance in (p_{T}, y) are analyzed. While for 27 and 54.4 GeV collisions the C_{6}/C_{2} values are close to zero within uncertainties, it is observed that for 200 GeV collisions, the C_{6}/C_{2} ratio becomes progressively negative from peripheral to central collisions. Transport model calculations without critical dynamics predict mostly positive values except for the most central collisions within uncertainties. These observations seem to favor a smooth crossover in the high-energy nuclear collisions at top RHIC energy.

The Identification of a Tumor Infiltration CD8+ T-Cell Gene Signature That Can Potentially Improve the Prognosis and Prediction of Immunization Responses in Papillary Renal Cell Carcinoma

Background

CD8+ T cells, vital effectors pertaining to adaptive immunity, display close relationships to the immunization responses to kill tumor cells. Understanding the effect exerted by tumor infiltration CD8+ T cells in papillary renal cell carcinoma (papRCC) is critical for assessing the prognosis process and responses to immunization therapy in cases with this disease.

Materials and Approaches

The single-cell transcriptome data of papRCC were used for screening CD8+ T-cell-correlated differentially expressed genes to achieve the following investigations. On that basis, a prognosis gene signature associated with tumor infiltration CD8+ T cell was built and verified with The Cancer Genome Atlas data set. Risk scores were determined for papRCC cases and categorized as high- or low-risk groups. The prognosis significance for risk scores was assessed with multiple-variate Cox investigation and Kaplan–Meier survival curves. In addition, the possible capability exhibited by the genetic profiles of cases to assess the response to immunization therapy was further explored.

Results

Six hundred twenty-one cell death-inhibiting RNA genes were screened using single-cell RNA sequencing. A gene signature consisting of seven genes (LYAR, YBX1, PNRC1, TCF25, MYL12B, MINOS1, and LINC01420) was then identified, and this collective was considered to be an independent prognosis indicator that could strongly assess overall survival in papRCC. In addition, the data allowed papRCC cases to fall to cohorts at high and low risks, exhibiting a wide range of clinically related features as well as different CD8+ T-cell immunization infiltration and immunization therapy responses.

Conclusions

Our work provides a possible explanation for the limited response of current immunization checkpoint-inhibiting elements for combating papRCC. Furthermore, the researchers built a novel genetic signature that was able to assess the prognosis and immunotherapeutic response of cases. This may also be considered as a promising therapeutic target for the disease.

Branching Fraction Measurements of the Rare B_{s}^{0}→ϕμ^{+}μ^{-} and B_{s}^{0}→f_{2}^{'}(1525)μ^{+}μ^{-} Decays

The branching fraction of the rare B_{s}^{0}→ϕμ^{+}μ^{-} decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6  fb^{-1}, respectively. The branching fraction is reported in intervals of q^{2}, the square of the dimuon invariant mass. In the q^{2} region between 1.1 and 6.0  GeV^{2}/c^{4}, the measurement is found to lie 3.6 standard deviations below a standard model prediction based on a combination of light cone sum rule and lattice QCD calculations. In addition, the first observation of the rare B_{s}^{0}→f_{2}^{'}(1525)μ^{+}μ^{-} decay is reported with a statistical significance of 9 standard deviations and its branching fraction is determined.

A Prediction Rule Including Interleukin-6 in Pericardial Drainage Improves Prediction of New-Onset Atrial Fibrillation After Coronary Artery Bypass Grafting

OBJECTIVE

To test the hypothesis that a prediction rule including levels of interleukin-6 in pericardial drainage (pdIL-6) would improve the discrimination in classifying patients undergoing coronary artery bypass grafting (CABG) into different postoperative atrial fibrillation (POAF) risk levels.

DESIGN

Prospective cohort study.

SETTING

A university-affiliated tertiary hospital.

PARTICIPANTS

Patients undergoing CABG.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We prospectively recruited patients who underwent CABG into derivation and validation cohorts. The independent predictors were identified in the derivation cohort using multiple logistic regression and tested in the validation cohort. The performance of the predictive model was tested using area under the receiver operating characteristic curve (AUC) in both cohorts. A prediction rule was created by assigning points to each predictor. Patients were classified in various risk levels according to their total risk scores. We enrolled 302 and 207 patients in the derivation and validation cohorts, respectively. Multiple logistic regression analysis identified six predictors: age ≥61 y, left atrial diameter ≥49 mm, right atrial diameter ≥45 mm, number of grafts ≥3, and serum uric acid ≥226 µmol/L and pdIL-6 levels ≥166 ng/mL at postoperative 12 h. The AUC of the model was 0.78 and 0.77 for the derivation and validation cohort, respectively, which was greatly increased by adding pdIL-6. Patients were stratified into low-risk, moderate-risk and high-risk groups.

CONCLUSIONS

A POAF prediction rule including pdIL-6 had good performance for stratifying CABG patients into various risk groups for POAF. The inclusion of pdIL-6 resulted in clinically meaningful improvement in risk prediction.

[A case report of orbital epithelioid hemangioendothelioma]

A 70-year-old male patient, who had a right upper eyelid tumor excision 4 years ago, complained of eyelid swelling and ptosis for 3 months. Orbital CT and MRI showed an orbital cystic lesion with hemorrhage in the right eye. The tumor was resected under general anesthesia. The pathological diagnosis was epithelioid hemangioendothelioma. (Chin J Ophthalmol, 2021, 57:696-698).

Observation of the Mass Difference between Neutral Charm-Meson Eigenstates

A measurement of mixing and CP violation in neutral charm mesons is performed using data reconstructed in proton-proton collisions collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4  fb^{-1}. A total of 30.6 million D^{0}→K_{S}^{0}π^{+}π^{-} decays are analyzed using a method optimized for the measurement of the mass difference between neutral charm-meson eigenstates. Allowing for CP violation in mixing and in the interference between mixing and decay, the mass and decay-width differences are measured to be x_{CP}=[3.97±0.46(stat)±0.29(syst)]×10^{-3} and y_{CP}=[4.59±1.20(stat)±0.85(syst)]×10^{-3}, respectively. The CP-violating parameters are measured as Δx=[-0.27±0.18(stat)±0.01(syst)]×10^{-3} and Δy=[0.20±0.36(stat)±0.13(syst)]×10^{-3}. This is the first observation of a nonzero mass difference in the D^{0} meson system, with a significance exceeding seven standard deviations. The data are consistent with CP symmetry and improve existing constraints on the associated parameters.

Observation of D_{s}^{±}/D^{0} Enhancement in Au+Au Collisions at sqrt[s_{NN}]=200 GeV

We report on the first measurement of charm-strange meson D_{s}^{±} production at midrapidity in Au+Au collisions at sqrt[s_{NN}]=200  GeV from the STAR experiment. The yield ratio between strange (D_{s}^{±}) and nonstrange (D^{0}) open-charm mesons is presented and compared to model calculations. A significant enhancement, relative to a pythia simulation of p+p collisions, is observed in the D_{s}^{±}/D^{0} yield ratio in Au+Au collisions over a large range of collision centralities. Model calculations incorporating abundant strange-quark production in the quark-gluon plasma and coalescence hadronization qualitatively reproduce the data. The transverse-momentum integrated yield ratio of D_{s}^{±}/D^{0} at midrapidity is consistent with a prediction from a statistical hadronization model with the parameters constrained by the yields of light and strange hadrons measured at the same collision energy. These results suggest that the coalescence of charm quarks with strange quarks in the quark-gluon plasma plays an important role in D_{s}^{±}-meson production in heavy-ion collisions.

Erratum: Azimuthal Anisotropy of K_{S}^{0} and Λ+Λ[over ¯] Production at Midrapidity from Au+Au Collisions at sqrt[s]_{NN}=130 GeV [Phys. Rev. Lett. 89, 132301 (2002)]

This corrects the article DOI: 10.1103/PhysRevLett.89.132301.