Observation of B^{0}→pΛ[over ¯]D^{(*)-}

We report the first observation of the decays B^{0}→pΛ[over ¯]D^{(*)-}. The data sample of 711  fb^{-1} used in this analysis corresponds to 772×10^{6} BB[over ¯] pairs, collected at the ϒ(4S) resonance by the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We observe 19.8σ and 10.8σ excesses of events for the two decay modes and measure the branching fractions of B^{0}→pΛ[over ¯]D^{-} and B^{0}→pΛ[over ¯]D^{*-} to be (25.1±2.6±3.5)×10^{-6} and (33.6±6.3±4.4)×10^{-6}, respectively, where the first uncertainties are statistical and the second are systematic. These results are not compatible with the predictions based on the generalized factorization approach. In addition, a threshold enhancement in the dibaryon (pΛ[over ¯]) system is observed, consistent with that observed in similar B decays.

Role of Oestrogen α Receptors in Sociosexual Behaviour in Female Rats Housed in a Seminatural Environment

The present study investigated the role of oestrogen receptor (ER)α in the ventromedial nucleus of the hypothalamus (VMN), the preoptic area (POA), the medial amygdala (MePD) and the bed nucleus of stria terminalis (BNST) in sociosexual behaviour in female rats. This was conducted in two sets of experiments, with the VMN and POA investigated in the first set, and the MePD and BNST in the second set. The VMN and POA received intense projections from the MePD and BNST. We used a short hairpin RNA encoded within an adeno-associated viral vector directed against the gene for ERα to reduce the number of ERα in the VMN or POA (first set of experiments) or in the BNST or MePD (second set of experiments) in female rats. The rats were housed in groups of four ovariectomised females and three males in a seminatural environment for 8 days. Compared with traditional test set-ups, the seminatural environment provides an arena in which the rats can express their full behavioural repertoire, which allowed us to investigate multiple aspects of social and sexual behaviour in groups of rats. Behavioural observation was performed after oestrogen and progesterone injections. A reduction of ERα expression in the VMN or POA diminished the display of paracopulatory behaviours and lordosis responses compared to controls, whereas the lordosis quotient remained unaffected. This suggests that ERα in the VMN and POA play an important role in intrinsic sexual motivation. The reduction in ERα did not affect the social behaviour of the females, although the males sniffed and pursued the females with reduced ERα less than the controls. This suggests that the ERα in the VMN and POA is involved in the regulation of sexual attractiveness of females. The ERα in the MePD and BNST, on the other hand, plays no role in sociosexual behaviour.

First Observation of the Hadronic Transition ϒ(4S)→ηh(b)(1P) and New Measurement of the h(b)(1P) and η(b)(1S) Parameters

Using a sample of 771.6×10(6) ϒϒ(4S) decays collected by the Belle experiment at the KEKB e(+)e(-) collider, we observe, for the first time, the transition ϒ(4S)→ηh(b)(1P) with the branching fraction B[ϒ(4S)→ηh(b)(1P)]=(2.18±0.11±0.18)×10(-3) and we measure the h(b)(1P) mass M(h(b)(1P))=(9899.3±0.4±1.0)  MeV/c(2), corresponding to the hyperfine (HF) splitting ΔM(HF)(1P)=(0.6±0.4±1.0)  MeV/c(2). Using the transition h(b)(1P)→γη(b)(1S), we measure the η(b)(1S) mass M(η(b)(1S))=(9400.7±1.7±1.6)  MeV/c(2), corresponding to ΔM(HF)(1S)=(59.6±1.7±1.6)  MeV/c(2), the η(b)(1S) width Γ(η(b)(1S))=(8(-5)(+6)±5)  MeV/c(2) and the branching fraction B[h(b)(1P)→γη(b)(1S)]=(56±8±4)%.

First Observation of CP Violation in B[over ¯]^{0}→D_{CP}^{(*)}h^{0} Decays by a Combined Time-Dependent Analysis of BABAR and Belle Data

We report a measurement of the time-dependent CP asymmetry of B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays, where the light neutral hadron h^{0} is a π^{0}, η, or ω meson, and the neutral D meson is reconstructed in the CP eigenstates K^{+}K^{-}, K_{S}^{0}π^{0}, or K_{S}^{0}ω. The measurement is performed combining the final data samples collected at the ϒ(4S) resonance by the BABAR and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6} BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6} BB[over ¯] pairs recorded by the Belle detector. We measure the CP asymmetry parameters -η_{f}S=+0.66±0.10(stat)±0.06(syst) and C=-0.02±0.07(stat)±0.03(syst). These results correspond to the first observation of CP violation in B[over ¯]^{0}→D_{CP}^{(*)}h^{0} decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations.

Discovery of τ Neutrino Appearance in the CNGS Neutrino Beam with the OPERA Experiment

The OPERA experiment was designed to search for ν_{μ}→ν_{τ} oscillations in appearance mode, i.e., by detecting the τ leptons produced in charged current ν_{τ} interactions. The experiment took data from 2008 to 2012 in the CERN Neutrinos to Gran Sasso beam. The observation of the ν_{μ}→ν_{τ} appearance, achieved with four candidate events in a subsample of the data, was previously reported. In this Letter, a fifth ν_{τ} candidate event, found in an enlarged data sample, is described. Together with a further reduction of the expected background, the candidate events detected so far allow us to assess the discovery of ν_{μ}→ν_{τ} oscillations in appearance mode with a significance larger than 5σ.

Search for the dark photon and the dark Higgs boson at belle

The dark photon A^{'} and the dark Higgs boson h^{'} are hypothetical constituents featured in a number of recently proposed dark sector models. Assuming prompt decays of both dark particles, we search for their production in the so-called Higgstrahlung channel e^{+}e^{-}→A^{'}h^{'}, with h^{'}→A^{'}A^{'}. We investigate ten exclusive final states with A^{'}→e^{+}e^{-}, μ^{+}μ^{-}, or π^{+}π^{-} in the mass ranges 0.1  GeV/c^{2} <m_{A^{'}}<3.5  GeV/c^{2} and 0.2  GeV/c^{2} <m_{h^{'}}<10.5  GeV/c^{2}. We also investigate three inclusive final states 2(e^{+}e^{-})X, 2(μ^{+}μ^{-})X, and (e^{+}e^{-})(μ^{+}μ^{-})X, where X denotes a dark photon candidate detected via missing mass, in the mass ranges 1.1  GeV/c^{2} <m_{A^{'}}<3.5  GeV/c^{2} and 2.2  GeV/c^{2} <m_{h^{'}}<10.5  GeV/c^{2}. Using the entire 977  fb^{-1} data set collected by Belle, we observe no significant signal. We obtain individual and combined 90% credibility level upper limits on the branching fraction times the Born cross section, B×σ_{Born}, on the Born cross section σ_{Born}, and on the dark photon coupling to the dark Higgs boson times the kinetic mixing between the standard model photon and the dark photon, α_{D}×ε^{2}. These limits improve upon and cover wider mass ranges than previous experiments. The limits from the final states 3(π^{+}π^{-}) and 2(e^{+}e^{-})X are the first placed by any experiment. For α_{D} equal to 1/137, m_{h^{'}}< 8  GeV/c^{2}, and m_{A^{'}}<1  GeV/c^{2}, we exclude values of the mixing parameter ε above ∼8×10^{-4}.

Realization of a micrometre-scale spin-wave interferometer

The recent development of spin dynamics opens perspectives for various applications based on spin waves, including logic devices. The first important step in the realization of spin-wave-based logics is the manipulation of spin-wave interference. Here, we present the experimental realization of a micrometre-scale spin-wave interferometer consisting of two parallel spin-wave waveguides. The spin waves propagate through the waveguides and the superposition or interference of the electrical signals corresponding to the spin waves is measured. A direct current flowing through a metal wire underneath one of the spin-wave waveguides affects the propagation properties of the corresponding spin wave. The signal of constructive or destructive interference depends on the magnitude and direction of the applied direct current. Thus, the present work demonstrates a unique manipulation of spin-wave interference.

Measurement of the Direct CP Asymmetry in B¯→X(s+dγ) Decays with a Lepton Tag

We report the measurement of the direct CP asymmetry in the radiative B¯→X(s+dγ) decay using a data sample of (772 ± 11)×10(6) BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The CP asymmetry is measured as a function of the photon energy threshold. For Eγ*≥2.1  GeV, where Eγ* is the photon energy in the center-of-mass frame, we obtain A(CP)(B¯→X(s+dγ))=(2.2±3.9±0.9)%, consistent with the standard model prediction.

Observation of e+e- → π+π-π(0)(χbJ) and Search for X(b) → ωϒ(1S) at sqrt[s] = 10.867 GeV

The e(+)e(-) → π(+)π(-)π(0)χ(bJ) (J = 0,1,2) processes are studied using a 118 fb(-1) data sample acquired with the Belle detector at a center-of-mass energy of 10.867 GeV. Unambiguous π(+)π(-)π(0)χ(bJ) (J = 1,2), ωχ(b1) signals are observed, and indication for ωχ(b2) is seen, both for the first time, and the corresponding cross section measurements are presented. No significant π(+)π(-)π(0)χ(b0) or ωχ(b0) signals are observed, and 90% confidence level upper limits on the cross sections for these two processes are obtained. In the π(+)π(-)π(0) invariant mass spectrum, significant non-ω signals are also observed. We search for the X(3872)-like state (named X(b)) decaying into ωϒ(1S); no significant signal is observed with a mass between 10.55 and 10.65 GeV/c(2).

Diagnostic potential of antibody titres against Candida cell wall β-glucan in Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis syndrome of unknown aetiology in children. The administration of Candida cell wall antigens induced KD-like coronary vasculitis in mice. However, the responses of KD patients to Candida cell wall antigen are unknown. In this study, we examined the response of KD patients to β-glucan (BG), one of the major fungal cell wall antigens, by measuring the anti-BG titre. In KD patients, the anti-C. albicans cell wall BG titre was higher than that in normal children. The anti-BG titre was also higher in KD patients compared to children who served as control subjects. The efficacy of intravenous immunoglobulin (IVIG) therapy in KD is well established. We categorized the KD patients into three groups according to the therapeutic efficacy of intravenous immunoglobulin (IVIG) and compared the anti-BG titre among these groups. Anti-BG titres were similar in the control group and the non-responsive group. In the fully responsive group, the anti-BG titre showed higher values than those in the normal children. This study demonstrated clinically that KD patients have high antibody titres to Candida cell wall BG, and suggested the involvement of Candida cell wall BG in the pathogenesis of KD. The relationship between IVIG therapy and anti-BG titre was also shown. These results provide valuable insights into the therapy and diagnosis of KD.

Measurement of the branching fraction B(Λc+ → pK-π+)

We present the first model-independent measurement of the absolute branching fraction of the Λ(c)(+) → pK(-)π(+) decay using a data sample of 978 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The number of Λ(c)(+) baryons is determined by reconstructing the recoiling D((*)-) pπ(+) system in events of the type e(+)e(-) → D((*)-) pπ(+)Λ(c)(+). The branching fraction is measured to be B(Λ(c)(+) → pK(-)π(+)) = (6.84 ± 0.24(-0.27)(+0.21))%, where the first and second uncertainties are statistical and systematic, respectively.

Diurnal and circadian oscillations in expression of kisspeptin, kisspeptin receptor and gonadotrophin-releasing hormone 2 genes in the grass puffer, a semilunar-synchronised spawner

In seasonally breeding animals, the circadian and photoperiodic regulation of neuroendocrine system is important for precisely-timed reproduction. Kisspeptin, encoded by the Kiss1 gene, acts as a principal positive regulator of the reproductive axis by stimulating gonadotrophin-releasing hormone (GnRH) neurone activity in vertebrates. However, the precise mechanisms underlying the cyclic regulation of the kisspeptin neuroendocrine system remain largely unknown. The grass puffer, Takifugu niphobles, exhibits a unique spawning rhythm: spawning occurs 1.5-2 h before high tide on the day of spring tide every 2 weeks, and the spawning rhythm is connected to circadian and lunar-/tide-related clock mechanisms. The grass puffer has only one kisspeptin gene (kiss2), which is expressed in a single neural population in the preoptic area (POA), and has one kisspeptin receptor gene (kiss2r), which is expressed in the POA and the nucleus dorsomedialis thalami. Both kiss2 and kiss2r show diurnal variations in expression levels, with a peak at Zeitgeber time (ZT) 6 (middle of day time) under the light/dark conditions. They also show circadian expression with a peak at circadian time 15 (beginning of subjective night-time) under constant darkness. The synchronous and diurnal oscillations of kiss2 and kiss2r expression suggest that the action of Kiss2 in the diencephalon is highly dependent on time. Moreover, midbrain GnRH2 gene (gnrh2) but not GnRH1 or GnRH3 genes show a unique semidiurnal oscillation with two peaks at ZT6 and ZT18 within a day. The cyclic expression of kiss2, kiss2r and gnrh2 may be important in the control of the precisely-timed diurnal and semilunar spawning rhythm of the grass puffer, possibly through the circadian clock and melatonin, which may transmit the photoperiodic information of daylight and moonlight to the reproductive neuroendocrine centre in the hypothalamus.