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論文

First search for the $$eta_{c2}(1D)$$ in $$B$$ decays at Belle

Chilikin, K.*; 谷田 聖; Belle Collaboration*; 他194名*

Journal of High Energy Physics (Internet), 2020(5), p.34_1 - 34_22, 2020/05

 被引用回数:0 パーセンタイル:100(Physics, Particles & Fields)

The first dedicated search for the $$eta_{c2}(1D)$$ is carried out using the decays $$B^+ rightarrow eta_{c2}(1D) K^+$$, $$B^0 rightarrow eta_{c2}(1D) K^0_S$$, $$B^0 rightarrow eta_{c2}(1D) pi^- K^+$$, and $$B^+ rightarrow eta_{c2}(1D) pi^+ K^0_S$$ with $$eta_{c2}(1D) to h_c gamma$$. No significant signal is found. For the $$eta_{c2}(1D)$$ mass range between $$3795$$ and $$3845 mathrm{MeV}/c^2$$, the branching-fraction upper limits are determined to be $$mathcal{B}(B^+ rightarrow eta_{c2}(1D) K^+) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 3.7 times 10^{-5}$$, $$mathcal{B}(B^0 rightarrow eta_{c2}(1D) K^0_S) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 3.5 times 10^{-5}$$, $$mathcal{B}(B^0 rightarrow eta_{c2}(1D) pi^- K^+) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 1.0 times 10^{-4}$$, and $$mathcal{B}(B^+ rightarrow eta_{c2}(1D) pi^+ K^0_S) times mathcal{B}(eta_{c2}(1D) to h_c gamma) < 1.1 times 10^{-4}$$ at 90% C. L. The analysis is based on the 711 $$mathrm{fb}^{-1}$$ data sample collected on the $$Upsilon(4S)$$ resonance by the Belle detector, which operated at the KEKB asymmetric-energy $$e^+ e^-$$ collider.

論文

Evidence for a vector charmoniumlike state in $$e^+e^- to D^+_sD^*_{s2}(2573)^-+c.c.$$

Jia, S.*; 谷田 聖; Belle Collaboration*; 他175名*

Physical Review D, 101(9), p.091101_1 - 091101_8, 2020/05

 被引用回数:2 パーセンタイル:18.33(Astronomy & Astrophysics)

We report the measurement of $$e^+e^- to D^+_sD^*_{s2}(2573)^-+c.c.$$ via initial-state radiation using a data sample of an integrated luminosity of 921.9 fb$$^{-1}$$ collected with the Belle detector at the $$Upsilon(4S)$$ and nearby. We find evidence for an enhancement with a 3.4$$sigma$$ significance in the invariant mass of $$D^+_sD^*_{s2}(2573)^- +c.c.$$ The measured mass and width are $$(4619.8^{+8.9}_{-8.0}({rm stat.})pm2.3({rm syst.}))~{rm MeV}/c^{2}$$ and $$(47.0^{+31.3}_{-14.8}({rm stat.})pm4.6({rm syst.}))~{rm MeV}$$, respectively. The mass, width, and quantum numbers of this enhancement are consistent with the charmonium-like state at 4626 MeV/$$c^2$$ recently reported by Belle in $$e^+e^-to D^+_sD_{s1}(2536)^-+c.c.$$ The product of the $$e^+e^-to D^+_sD^*_{s2}(2573)^-+c.c.$$ cross section and the branching fraction of $$D^*_{s2}(2573)^-to{bar D}^0K^-$$ is measured from $$D^+_sD^*_{s2}(2573)^-$$ threshold to 5.6 GeV.

論文

Three-body decay of $$Lambda_c^{*} (2765)$$ and determination of its spin-parity

Arifi, A. J.*; 永廣 秀子*; 保坂 淳; 谷田 聖

Physical Review D, 101(9), p.094023_1 - 094023_17, 2020/05

 被引用回数:1 パーセンタイル:37.09(Astronomy & Astrophysics)

We study three-body decays of $$Lambda_c^{*}(2765) to Lambda_c^+pi^+pi^-$$ by using effective Lagrangians in a non-relativistic framework. We consider the sequential decays through $$Sigma_c(2455)pi$$ and $$Sigma_c^*(2520)pi$$ in intermediate states which are dominant contributions. The coupling constants in the effective Lagrangians are computed in the quark model. We demonstrate that the ratio $$R= Gamma(Lambda_c^*toSigma_c^*(2520)pi)/Gamma(Lambda_c^*to Sigma_c(2455)pi)$$ and angular correlations are sensitive to the spin and parity of $$Lambda_c^{*}(2765)$$. Thus, the measurement of these observables in experimental facilities such as Belle and LHCb can provide useful constraints to determine the spin and parity of $$Lambda_c^{*}(2765)$$.

論文

Observation of the radiative decays of $$Upsilon(1S)$$ to $$chi_{c1}$$

Katrenko, P.*; 谷田 聖; Belle Collaboration*; 他168名*

Physical Review Letters, 124(12), p.122001_1 - 122001_7, 2020/03

 被引用回数:1 パーセンタイル:27.71(Physics, Multidisciplinary)

We report the first observation of the radiative decay of the $$Upsilon(1S)$$ into a charmonium state. The statistical significance of the observed signal of $$Upsilon(1S) to gamma chi_{c1}$$ is 6.3 standard deviations including systematics. The branching fraction is calculated to be Br($$Upsilon(1S) to gamma chi_{c1}$$) = $$(4.7^{+2.4}_{-1.8} (stat) ^{+0.4}_{-0.5} (sys)) times 10^{-5}$$. We also searched for $$Upsilon(1S)$$ radiative decays into $$chi_{c0,2}$$ and $$eta_c(1S,2S)$$ and set upper limits on their branching fractions. These results are obtained from a 24.9 fb$$^{-1}$$ data sample collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider at a center-of-mass energy equal to the $$Upsilon(2S)$$ mass using $$Upsilon(1S)$$ tagging by the $$Upsilon(2S) to Upsilon(1S) pi^+pi^-$$ transitions.

論文

Observation of a vector charmoniumlike state in $$e^+e^- to D^+_sD_{s1}(2536)^-+c.c.$$

Jia, S.*; 谷田 聖; Belle Collaboration*; 他172名*

Physical Review D, 100(11), p.111103_1 - 111103_8, 2019/12

 被引用回数:10 パーセンタイル:10.06(Astronomy & Astrophysics)

Using a data sample of 921.9 fb$$^{-1}$$ collected with the Belle detector, we study the process of $$e^+e^-to D^+_sD_{s1}(2536)^-+c.c.$$ via initial-state radiation. We report the first observation of a vector charmoniumlike state decaying to $$D^+_sD_{s1}(2536)^-+c.c.$$ with a significance of 5.9$$sigma$$, including the systematic uncertainties. The measured mass and width are $$(4625.9^{+6.2}_{-6.0}({rm stat.})pm0.4({rm syst.}))~{rm MeV}/c^{2}$$ and $$(49.8^{+13.9}_{-11.5}({rm stat.})pm4.0({rm syst.}))~{rm MeV}$$, respectively. The product of the $$e^+e^-to D^+_sD_{s1}(2536)^-+c.c.$$ cross section and the branching fraction of $$D_{s1}(2536)^-to{bar D}^{*0}K^-$$ is measured from the $$D_s bar{D}_{s1}(2536)$$ threshold to 5.59 GeV.

論文

Experimental study of Di-quark correlation by charmed baryon spectroscopy at J-PARC high-momentum secondary beam line

小松 雄哉*; 市川 裕大; 成木 恵*; 谷田 聖; 他24名*

JPS Conference Proceedings (Internet), 26, p.022029_1 - 022029_4, 2019/11

A di-quark correlation has been proposed to describe the internal structure of hadrons, especially those of exotic ones. Nevertheless it lacks a conclusive experimental evidence. The J-PARC E50 experiment performs charmed baryon spectroscopy at J-PARC high-momentum beam line to investigate the role of di-quark correlations in baryons. The energy levels of the excited sates are measured by a missing-mass technique for the first time, and the production rates and decay branching ratios are also measured.

論文

$$Lambda(1405)$$ spectroscopy via the in-flight $$d(K^-, n)$$ reaction at the J-PARC K1.8BR

川崎 新吾*; 橋本 直; 谷田 聖; 他72名*

JPS Conference Proceedings (Internet), 26, p.022009_1 - 022009_5, 2019/11

The spectral shape of the $$Lambda(1405)$$ baryon was measured via the in-flight $$d(K^-, n)$$ reaction at the J-PARC K1.8BR beam-line (J-PARC E31). The second E31 physics run was carried out in January and February, 2018. Approximately $$3.9 times 10^{10}$$ kaons were irradiated on the deuteron target. The missing mass spectrum for the $$d(K^-, n)$$ where the residual final-state particles were $$Sigma^0$$ and $$pi^0$$ ($$d(K^-, n)$$"$$Sigma^0pi^0$$" spectrum) was measured for the first time.

論文

Observation of a new structure near 10.75 GeV in the energy dependence of the $$e^{+}$$e$$^{-} to Upsilon(nS) pi^{+}pi^{-}$$ $$(n = 1, 2, 3)$$ cross sections

Mizuk, R.*; 谷田 聖; Belle Collaboration*; 他181名*

Journal of High Energy Physics (Internet), 2019(10), p.220_1 - 220_26, 2019/10

 被引用回数:4 パーセンタイル:43.79

We report a new measurement of the $$e^+e^-toUpsilon(nS)pi^+pi^-$$ ($$n=1,2,3$$) cross sections at energies from 10.52 to 11.02 GeV using data collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. We observe a new structure in the energy dependence of the cross sections; if described by a Breit-Wigner function its mass and width are found to be $$M=(10752.7pm5.9,^{+0.7}_{-1.1}),$$MeV/$$c^2$$ and $$Gamma=(35.5^{+17.6}_{-11.3},^{+3.9}_{-3.3}),$$MeV, where the first error is statistical and the second is systematic. The global significance of the new structure that includes a systematic uncertainty is 6.7 standard deviations. We also find evidence for the $$e^+e^-toUpsilon(1S)pi^+pi^-$$ process at the energy 10.52 GeV, which is below the $$Bbar{B}$$ threshold.

論文

Search for $$Omega(2012)to KXi(1530) to KpiXi$$ at Belle

Jia, S.*; 谷田 聖; Belle Collaboration*; 他193名*

Physical Review D, 100(3), p.032006_1 - 032006_11, 2019/08

 被引用回数:3 パーセンタイル:43.79(Astronomy & Astrophysics)

Using data samples of $$e^+e^-$$ collisions collected at the $$Upsilon(1S)$$, $$Upsilon(2S)$$, and $$Upsilon(3S)$$ resonances with the Belle detector, we search for the three-body decay of the $$Omega(2012)$$ baryon to $$KpiXi$$. This decay is predicted to dominate for models describing the $$Omega(2012)$$ as a $$KXi(1530)$$ molecule. No significant $$Omega(2012)$$ signals are observed in the studied channels, and 90% credibility level upper limits on the ratios of the branching fractions relative to $$K Xi$$ decay modes are obtained.

論文

Prospects for the spin structure study of hyperons using heavy quark decays at Belle II

谷田 聖

Proceedings of Science (Internet), 346, 6 Pages, 2019/08

The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $$e^+ e^-$$ collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and first electron positron collisions in Belle II were obtained on April 26, 2018. The design luminosity of SuperKEKB is $$8 times 10^{35}$$ cm$$^{-2}$$s$$^{-1}$$ and the Belle II experiment aims to record 50 ab$$^{-1}$$ of data, a factor of 50 more than the Belle experiment. In this talk, we will explain the idea of a hyperon spin structure study using heavy quark decays: In weak decays of heavy quarks, the daughter quarks are highly polarized. On the other hand, one can naively expect that the fraction of the baryon spin carried by a quark is equal to the polarization transfer of the quark to the baryon. In this way, one can experimentally determine the spin structures of hyperons in decays of heavy quarks. Spin structures of ground state hyperons (i.e., $$Lambda$$ and $$Sigma$$) are interesting in the context of the proton spin structure puzzle. In addition, excited states can be also studied to identify exotic hyperons. Especially in $$Lambda(1405)$$, a two pole structure may be seen as a mass dependence of the polarization.

論文

Possibility of a new narrow $$Lambda^*$$ resonance near the $$Lambda eta$$ threshold

谷田 聖

AIP Conference Proceedings 2130, p.040019_1 - 040019_6, 2019/07

 被引用回数:0 パーセンタイル:100

Evidence for a narrow $$Lambda^*$$ resonance at a mass of about 1665 MeV (just above the combined mass of the $$Lambda$$ ground state plus the $$eta$$ meson) has been seen in the $$M(pK^-)$$ mass of the Dalitz plot for $$Lambda_c to pK^-pi^+$$ decay at the Belle experiment. Additional evidence for this resonance is found in the partial-wave analysis (PWA) of data on $$K^- p$$ reactions done independently by several groups, driven by angular distributions of the $$K^- p to Lambdaeta$$ reaction by the Crystal Ball collaboration. If a narrow $$Lambda^*$$ resonance exists at this mass, then the conventional quark model cannot explain it, and a possible explanation is that it is a crypto-exotic baryon with a dominant meson-baryon component to its wave function. Therefore we have proposed a definitive experiment for $$K^- p to Lambda eta$$, using the newly built hypTPC detector to establish the existence of the proposed narrow $$Lambda(1665)$$ and determine its spin and parity in just two weeks of beamtime at J-PARC (E72). We will discuss these evidences for the proposed $$Lambda^*$$ resonance and introduce the E72 experiment.

論文

Exotic and conventional quarkonium physics prospects at Belle II

谷田 聖

AIP Conference Proceedings 2130, p.040020_1 - 040020_6, 2019/07

 被引用回数:2 パーセンタイル:4.52

The Belle II experiment, now operating at the KEK laboratory in Japan, is a substantial upgrade of both the Belle detector and the KEKB $$e^+ e^-$$ accelerator. It aims to collect 50 times more data than existing B-Factory samples. Belle II is uniquely capable to study the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First discovered by Belle, these now number in the dozens, and represent the emergence of a new category within quantum chromodynamics. This talk will present the capabilities of Belle II to explore both exotic and conventional quarkonium physics.

論文

Spectroscopic study of the $$Lambda$$(1405) resonance via the $$d(K^-, n)$$ reaction at J-PARC

浅野 秀光*; 橋本 直; 谷田 聖; 他72名*

AIP Conference Proceedings 2130, p.040018_1 - 040018_6, 2019/07

 被引用回数:0 パーセンタイル:100

The structure of the $$Lambda(1405)$$ hyperon is an important and long-standing issue related to the $$bar{K}$$-nucleus interaction. The J-PARC E31 experiment has been performed to investigate the $$Lambda(1405)$$ spectrum shape. Because it is hard to form the $$Lambda(1405)$$ directly by a $$bar{K}N$$ scattering in free space, E31 uses the $$d(K^-, n)$$ reaction with an incident kaon momentum of 1 GeV/$$c$$. We will identify three final states - $$Sigma^-pi^+$$, $$Sigma^+pi^-$$, $$Sigma^0pi^0$$ so that the isospin structure of hyperon resonance states produced can be decomposed. The first physics run of the E31 experiment was performed in 2016. To enhance the statistics of the data set, we have performed the second physics run in the beginning of 2018. During the second run of E31, around $$3.9 times 10^{10}$$ kaons impacted on the deuteron target.

論文

Hadronic Paschen-Back effect in P-wave charmonia under strong magnetic fields

岩崎 幸生; 岡 眞; 鈴木 渓*; 吉田 哲也*

International Journal of Modern Physics; Conference Series (Internet), 49, p.1960002_1 - 1960002_6, 2019/07

P波のチャーモニウムメソンに強い磁場がかかったときにスペクトルおよび波動関数がどのように変化するかを磁場の強さの関数として解析した。

論文

Search for $$B^0 to X(3872) gamma$$

Chou, P.-C.*; 谷田 聖; Belle Collaboration*; 他192名*

Physical Review D, 100(1), p.012002_1 - 012002_8, 2019/07

 被引用回数:0 パーセンタイル:100(Astronomy & Astrophysics)

We report the results of a search for the decay $$B^0 to X(3872)(to J/psi pi^+ pi^-) gamma$$. The analysis is performed on a data sample corresponding to an integrated luminosity of $$711,{rm fb}^{-1}$$ and containing $$772 times 10^6 Bbar{B}$$ pairs, collected with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider running at the $$Upsilon(4S)$$ resonance energy. We find no evidence for a signal and place an upper limit of $$mathcal{B}(B^0 to X(3872)gamma)times mathcal{B}(X(3872) to J/psi pi^+ pi^-) < 5.1 times 10^{-7}$$ at 90% confidence level.

論文

Search for $$X(3872)$$ and $$X(3915)$$ decay into $$chi_{c1} pi^0$$ in $$B$$ decays at Belle

Bhardwaj, V.*; 谷田 聖; Belle Collaboration*; 他191名*

Physical Review D, 99(11), p.111101_1 - 111101_8, 2019/06

 被引用回数:2 パーセンタイル:74.49(Astronomy & Astrophysics)

We report a search for $$X(3872)$$ and $$X(3915)$$ in $$B^+ to chi_{c1} pi^0 K^+$$ decays. We set an upper limit of $$mathcal{B}(B^+ to X(3872) K^+) times mathcal{B}(X(3872) to chi_{c1} pi^0)$$ $$ < 8.1 times 10^{-6}$$ and $$mathcal{B}(B^+ to X(3915) K^+) times mathcal{B}(X(3915) to chi_{c1} pi^0)$$ $$ < 3.8 times 10^{-5}$$ at 90% confidence level. We also measure $$mathcal{B}(X(3872) to chi_{c1} pi^0)/mathcal{B}(X(3872) to J/psi pi^+ pi^-) < 0.97$$ at 90% confidence level. The results reported here are obtained from $$772 times 10^{6}$$ $$Boverline{B}$$ events collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider.

論文

Search for the $$B to Y(4260) K, ~Y(4260) to J/psi pi^+pi^-$$ decays

Garg, R.*; 谷田 聖; Belle Collaboration*; 他172名*

Physical Review D, 99(7), p.071102_1 - 071102_8, 2019/04

 被引用回数:2 パーセンタイル:74.49(Astronomy & Astrophysics)

We report the results of a search for the $$B to Y(4260) K, ~Y(4260)to J/psipi^+pi^-$$ decays. This study is based on a data sample corresponding to an integrated luminosity of 711 fb$$^{-1}$$, collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. We investigate the $$J/psipi^+pi^-$$ invariant mass distribution in the range 4.0 to 4.6 GeV/$$c^2$$ using both $$B^+ to J/psi pi^+pi^- K^+$$ and $$B^0 to J/psi pi^+pi^- K^0_S$$ decays. We find excesses of events above the background levels, with a significances of 2.1 and 0.9 standard deviations for charged and neutral $$B to Y(4260) K$$ decays, respectively, taking into account the systematic uncertainties. These correspond to upper limits on the product of branching fractions, $${cal B}(B^+ to Y(4260) K^+) times {cal B}(Y(4260) to J/psi pi^+ pi^-) < 1.4 times 10^{-5}$$ and $${cal B}(B^0 to Y(4260) K^0) times {cal B}(Y(4260) to J/psi pi^+ pi^-) < 1.7 times 10^{-5}$$ at the 90% confidence level.

論文

Hadronic Paschen-Back effect

岩崎 幸生; 岡 眞; 鈴木 渓*; 吉田 哲也*

Physics Letters B, 790, p.71 - 76, 2019/03

 被引用回数:3 パーセンタイル:24.4(Astronomy & Astrophysics)

ヘビークォークを含むメソンに強い磁場がかかったときにスペクトルおよび波動関数がどのように変化するかを磁場の強さの関数として解析した。

論文

Measurement of the decays $$Lambda_cto Sigmapipi$$ at Belle

Berger, M.*; 谷田 聖; Belle Collaboration*; 他197名*

Physical Review D, 98(11), p.112006_1 - 112006_10, 2018/12

 被引用回数:4 パーセンタイル:55(Astronomy & Astrophysics)

We report measurements of the branching fractions of the decays $$Lambda^+_ctoSigma^+pi^-pi^+$$, $$Lambda^+_ctoSigma^0pi^+pi^0$$ and $$Lambda^+_ctoSigma^+pi^0pi^0$$ relative to the reference channel $$Lambda^+_cto pK^-pi^+$$. The analysis is based on the full data sample collected at and close to $$Upsilon(4S)$$ resonance by the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider corresponding to the integrated luminosity of 711 fb$$^{-1}$$. We measure $${cal B}(Lambda^+_crightarrowSigma^+pi^-pi^+)/{cal B}(Lambda^+_cto pK^-pi^+) = 0.706~pm 0.003~pm 0.029$$, $${cal B}(Lambda^+_crightarrowSigma^0pi^+pi^0)/{cal B}(Lambda^+_cto pK^-pi^+) = 0.491~pm 0.005~pm 0.028$$ and $${cal B}(Lambda^+_crightarrowSigma^+pi^0pi^0)/{cal B}(Lambda^+_cto pK^-pi^+) = 0.198~pm 0.006~pm 0.016$$. The listed uncertainties are statistical and systematic, respectively.

論文

Observation of $$Upsilon(2S)togamma eta_{b}(1S)$$ decay

Fulsom, B. G.*; 谷田 聖; Belle Collaboration*; 他197名*

Physical Review Letters, 121(23), p.232001_1 - 232001_8, 2018/12

 被引用回数:3 パーセンタイル:49.23(Physics, Multidisciplinary)

We report the observation of $$Upsilon(2S)togammaeta_{b}(1S)$$ decay based on analysis of the inclusive photon spectrum of $$24.7$$ fb$$^{-1}$$ of $$e^+ e^-$$ collisions at the $$Upsilon(2S)$$ center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. We measure a branching fraction of $$mathcal{B}(Upsilon(2S)togammaeta_{b}(1S))=(6.1^{+0.6+0.9}_{-0.7-0.5})times 10^{-4}$$, and derive an $$eta_{b}(1S)$$ mass of $$9394.8^{+2.7+4.5}_{-3.1-2.7}$$ MeV/$$c^{2}$$, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.

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