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論文

Evidence for the decay $$Omega_{c}^{0} to pi^+Omega(2012)^- to pi^+ (bar{K}Xi)^{-}$$

Li, Y.*; 谷田 聖; Belle Collaboration*; 他190名*

Physical Review D, 104(5), p.052005_1 - 052005_9, 2021/09

 被引用回数:9 パーセンタイル:65.5(Astronomy & Astrophysics)

Using a data sample of 980~fb$$^{-1}$$ collected with the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider, we present evidence for the $$Omega(2012)^-$$ in the resonant substructure of $$Omega_{c}^{0} to pi^+ (bar{K}Xi)^{-}$$ ($$(bar{K}Xi)^{-}$$ = $$K^-Xi^0$$ + $$bar{K}^0 Xi^-$$) decays. The significance of the $$Omega(2012)^-$$ signal is 4.2$$sigma$$ after considering the systematic uncertainties. The ratio of the branching fraction of $$Omega_{c}^{0} to pi^{+} Omega(2012)^- to pi^+ (bar{K}Xi)^{-}$$ relative to that of $$Omega_{c}^{0} to pi^{+} Omega^-$$ is calculated to be 0.220 $$pm$$ 0.059(stat.) $$pm$$ 0.035(syst.). The individual ratios of the branching fractions of the two isospin modes are also determined, and found to be $${cal B}(Omega_{c}^0 to pi^+ Omega(2012)^-) times {cal B}(Omega(2012)^- to K^-Xi^0)/{cal B}(Omega_{c}^0 to pi^+ K^- Xi^0)$$ =(9.6 $$pm$$ 3.2(stat.) $$pm$$ 1.8(syst.))% and $${cal B}(Omega_{c}^0 to pi^+ Omega(2012)^-) times {cal B}(Omega(2012)^- to bar{K}^0 Xi^-)/{cal B}(Omega_{c}^0 to pi^+ bar{K}^0 Xi^-)$$ = (5.5 $$pm$$ 2.8(stat.) $$pm$$ 0.7(syst.))%.

論文

Measurement of the masses and widths of the $$Sigma_c(2455)^+$$ and $$Sigma_c(2520)^+$$ baryons

Yelton, J.*; 谷田 聖; Belle Collaboration*; 他205名*

Physical Review D, 104(5), p.052003_1 - 052003_8, 2021/09

 被引用回数:4 パーセンタイル:37.94(Astronomy & Astrophysics)

Using 980 $${rm fb}^{-1}$$ of data ${collected}$ with the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider, we report the measurements of the masses, and the first measurements of the instrinsic widths, of the $$Sigma_c(2455)^+$$ and $$Sigma_c(2520)^+$$ charmed baryons. We find $$M(Sigma_c(2455)^+)-M(Lambda_c^+) = 166.17pm 0.05^{+0.16}_{-0.07} {rm MeV}/c^2$$, $$Gamma(Sigma_c(2455)^+) = 2.3 pm 0.3 pm 0.3 {rm MeV/c^2}$$, $$M(Sigma_c(2520)^+)-M(Lambda_c^+) = 230.9 pm 0.5 ^{+0.5}_{-0.1} {rm MeV}/c^2$$, and $$Gamma(Sigma_c(2520)^+) = 17.2^{+2.3 +3.1}_{-2.1 -0.7} {rm MeV}/c^2$$, where the uncertainties are statistical and systematic, respectively. These measurements can be used to test models of the underlying quark structure of the $$Sigma_c$$ states.

論文

Search for the $$eta_{c2}(1D)$$ in $$e^+e^-togammaeta_{c2}(1D)$$ at $$sqrt{s}$$ near 10.6 GeV at Belle

Jia, S.*; 谷田 聖; Belle Collaboration*; 他200名*

Physical Review D, 104(1), p.012012_1 - 012012_9, 2021/07

 被引用回数:0 パーセンタイル:0.01(Astronomy & Astrophysics)

For the first time we search for the $$eta_{c2}(1D)$$ in $$e^+e^-togammaeta_{c2}(1D)$$ at $$sqrt{s}$$ = 10.52, 10.58, and 10.867 GeV with data samples of 89.5 fb$$^{-1}$$, 711 fb$$^{-1}$$, and 121.4 fb$$^{-1}$$, respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant $$eta_{c2}(1D)$$ signal is observed in the mass range between 3.8 and 3.88 GeV/$$c^2$$. The upper limit at 90% confidence level on the product of the Born cross section for $$e^+e^- to gammaeta_{c2}(1D)$$ and branching fraction for $$eta_{c2}(1D)to gamma h_c(1P)$$ is determined to be $$sigma(e^+e^- to gammaeta_{c2}(1D)){cal B}(eta_{c2}(1D)to gamma h_c(1P))$$ $$<$$ 4.9 fb at $$sqrt{s}$$ near 10.6 GeV.

論文

Measurement of the energy dependence of the $$e^+e^-to Bbar{B}$$, $$Bbar{B}^*$$ and $$B^*bar{B}^*$$ exclusive cross sections

Mizuk, R.*; 谷田 聖; Belle Collaboration*; 他188名*

Journal of High Energy Physics (Internet), 2021(6), p.137_1 - 137_35, 2021/06

 被引用回数:6 パーセンタイル:45.23(Physics, Particles & Fields)

We report the first measurement of the exclusive cross sections $$e^+e^-to Bbar{B}$$, $$e^+e^-to Bbar{B}^*$$, and $$e^+e^-to B^*bar{B}^*$$ in the energy range from 10.63 GeV to 11.02 GeV. The $$B$$ mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy $$e^+e^-$$ collider.

論文

First determination of the spin and parity of the charmed-strange baryon $$Xi_{c}(2970)^+$$

Moon, T. J.*; 谷田 聖; Belle Collaboration*; 他203名*

Physical Review D, 103(11), p.L111101_1 - L111101_9, 2021/06

 被引用回数:18 パーセンタイル:85.82(Astronomy & Astrophysics)

We report results from a study of the spin and parity of $$Xi_{c}(2970)^+$$ using a $$980~mathrm{fb^{-1}}$$ data sample collected by the Belle detector at the KEKB asymmetric-energy $$e^{+}e^{-}$$ collider. The decay angle distributions in the chain $$Xi_{c}(2970)^+ to Xi_c(2645)^{0}pi^{+} to Xi_c^{+}pi^{-}pi^{+}$$ are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the $$Xi_{c}(2970)^+$$ spin $$J =1/2$$ over $$3/2$$ or $$5/2$$, under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of $$Xi_{c}(2970)^+$$ decay branching fractions $$R={mathcal{B}[ Xi_{c}(2970)^+ to Xi_c(2645)^{0}pi^{+} ]} $$ / $${ mathcal{B}[ Xi_{c}(2970)^+ to Xi_c^{prime0}pi^{+} ]} $$ =1.67 $$pm 0.29mathrm{(stat.)}^{ +0.15}_{-0.09}mathrm{(syst.)} $$ $$pm 0.25mathrm{(IS)}$$, where the last uncertainty is due to possible isospin-symmetry-breaking effects. This $$R$$ value favors the spin-parity $$J^P=1/2^+$$ with the spin of the light-quark degrees of freedom $$s_{l}=0$$. This is the first determination of the spin and parity of a charmed-strange baryon.

論文

Measurement of branching fractions of $$Lambda_{c}^{+} rightarrow etaLambdapi^{+}$$, $$eta Sigma^{0} pi^{+}$$, $$Lambda(1670) pi^{+}$$, and $$eta Sigma(1385)^{+}$$

Lee, J. Y.*; 谷田 聖; Belle Collaboration*; 他201名*

Physical Review D, 103(5), p.052005_1 - 052005_12, 2021/03

 被引用回数:6 パーセンタイル:51.62(Astronomy & Astrophysics)

We report branching fraction measurements of four decay modes of the $$Lambda_{c}^{+}$$ baryon, each of which includes an $$eta$$ meson and a $$Lambda$$ baryon in the final state, and all of which are measured relative to the $$Lambda_{c}^{+} rightarrow p K^{-} pi^{+}$$ decay mode. The results are based on a $$980~mathrm{fb^{-1}}$$ data sample collected by the Belle detector at the KEKB asymmetric-energy $$e^{+}e^{-}$$ collider. Two decays, $$eta Sigma^{0} pi^{+}$$ and $$Lambda(1670) pi^{+}$$, are observed for the first time, while the measurements of the other decay modes, $$Lambda_{c}^{+} rightarrow etaLambdapi^{+}$$ and $$etaSigma(1385)^{+}$$, are more precise than those made previously. We obtain $$mathcal{B}(Lambda_{c}^{+} rightarrow eta Lambda pi^{+})$$/$$mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$$ = $$0.293 pm 0.003 pm 0.014$$, $$mathcal{B}(Lambda_{c}^{+} rightarrow eta Sigma^{0} pi^{+})$$/$$mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$$ = $$0.120 pm 0.006 pm 0.006$$, $$mathcal{B}(Lambda_{c}^{+} rightarrow Lambda(1670) pi^{+}) times mathcal{B}(Lambda(1670) rightarrow etaLambda) $$/$$mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$$ = $$(5.54 pm 0.29 pm 0.73) times 10^{-2}$$, and $$mathcal{B}(Lambda_{c}^{+} rightarrow eta Sigma(1385)^{+}) $$/$$mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-}pi^{+})$$ = $$0.192 pm 0.006 pm 0.016$$. The mass and width of the $$Lambda(1670)$$ are also precisely determined to be $$1674.3 pm 0.8 pm 4.9~{rm MeV}/c^{2}$$ and $$36.1 pm 2.4 pm 4.8~{rm MeV}$$, respectively, where the uncertainties are statistical and systematic, respectively.

論文

Search for a doubly charged $$DDK$$ bound state in $$Upsilon(1S, 2S)$$ inclusive decays and via direct production in $$e^+e^-$$ collisions at $$sqrt{s}$$ = 10.520, 10.580, and 10.867 GeV

Li, Y.*; 谷田 聖; Belle Collaboration*; 他205名*

Physical Review D, 102(11), p.112001_1 - 112001_14, 2020/12

 被引用回数:5 パーセンタイル:36.79(Astronomy & Astrophysics)

We report the results of a first search for a doubly-charged $$DDK$$ bound state, denoted the $$R^{++}$$, in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ inclusive decays and via direct production in $$e^+e^-$$ collisions at $$sqrt{s}$$ = 10.520, 10.580, and 10.867 GeV. The search uses data accumulated with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. No significant signals are observed in the $$D^{+}D_{s}^{*+}$$ invariant-mass spectra of all studied modes. The 90% credibility level upper limits on their product branching fractions in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ inclusive decays ($${cal B}(Upsilon(1S,2S) to R^{++} + {rm anything}) times {cal B}(R^{++} to D^{+} D_{s}^{*+})$$), and the product values of Born cross section and branching fraction in $$e^+e^-$$ collisions ($$sigma(e^+e^- to R^{++} + {rm anything}) times {cal B}(R^{++} to D^{+} D_{s}^{*+})$$) at $$sqrt{s}$$ = 10.520, 10.580, and 10.867 GeV under different assumptions of $$R^{++}$$ masses varying from 4.13 to 4.17 GeV/$$c^2$$, and widths varying from 0 to 5 MeV are obtained.

論文

Search for transitions from $$Upsilon(4S)$$ and $$Upsilon(5S)$$ to $$eta_b(1S)$$ and $$eta_b(2S)$$ with emission of an $$omega$$ meson

Oskin, P.*; 谷田 聖; Belle Collaboration*; 他198名*

Physical Review D, 102(9), p.092011_1 - 092011_8, 2020/11

 被引用回数:0 パーセンタイル:0.01(Astronomy & Astrophysics)

Using data collected in the Belle experiment at the KEKB asymmetric-energy $$e^+e^-$$ collider we search for transitions $$Upsilon(4S) rightarrow eta_b(1S)omega$$, $$Upsilon(5S) rightarrow eta_b(1S)omega$$ and $$Upsilon(5S) rightarrow eta_b(2S)omega$$. No significant signals are observed and we set 90% confidence level upper limits on the corresponding visible cross sections: $$0.2 ~textrm{pb}, 0.4 ~textrm{pb}$$ and $$1.9 ~textrm{pb}$$, respectively.

論文

Study of electromagnetic decays of orbitally excited $$Xi_c$$ Baryons

Yelton, J.*; 谷田 聖; Belle Collaboration*; 他208名*

Physical Review D, 102(7), p.071103_1 - 071103_8, 2020/10

 被引用回数:8 パーセンタイル:51.82(Astronomy & Astrophysics)

Using 980 fb$$^{-1}$$ of data collected with the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider, we report a study of the electromagnetic decays of excited ${charmed baryons}$ $$Xi_c(2790)$$ and $$Xi_c(2815)$$. A clear signal (8.6 standard deviations) is observed for $$Xi_c(2815)^0 to Xi_c^0gamma$$, and we measure: $$B[Xi_c(2815)^0 to Xi_c^0gamma]/B[Xi_c(2815)^0 to Xi_c(2645)^+pi^- to Xi_c^0pi^+pi^-] = 0.41 pm 0.05 pm 0.03$$. We also present evidence (3.8 standard deviations) for the similar decay of the $$Xi_c(2790)^0$$ and measure: $$B[Xi_c(2790)^{0}toXi_c^{0}gamma]/B[Xi_c(2790)^0toXi_c^{prime +}pi^{-}toXi_c^{+}gamma pi^-] = 0.13 pm 0.03 pm 0.02$$. The first quoted uncertainties are statistical and the second systematic. We find no hint of the analogous decays of the $$Xi_c(2815)^+$$ and $$Xi_c(2790)^+$$ baryons and set upper limits at the 90% confidence level of: $$B[Xi_c(2815)^{+}toXi_c^{+}gamma]/B[Xi_c(2815)^+toXi_c(2645)^0pi^+toXi_c^+pi^-pi^+] < 0.09,$$ and $$B[Xi_c(2790)^{+}toXi_c^{+}gamma]/B[Xi_c(2790)^+toXi_c^{prime0}pi^{+}toXi_c^{0}gamma pi^+] < 0.06.$$ Approximate values of the partial widths of the decays are extracted, which can be used to discriminate between models of the underlying quark structure of these excited states.

論文

Measurements of the branching fractions $${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}^{'0})$$, $${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2645)^{0})$$ and $${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2790)^{0})$$

Li, Y.*; 谷田 聖; Belle Collaboration*; 他175名*

Physical Review D, 100(11), p.112010_1 - 112010_8, 2019/12

 被引用回数:1 パーセンタイル:7.79(Astronomy & Astrophysics)

Using the data sample of 711 fb$$^{-1}$$ of $$Upsilon(4S)$$ on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays $$B^{-} to bar{Lambda}_{c}^{-} Xi_{c}^{'0}$$, $$B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2645)^{0}$$, and $$B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2790)^{0}$$. The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against $$bar{Lambda}_{c}^{-}$$ baryons in selected $$B^-$$ candidates. The branching fraction of $$B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2790)^{0}$$ is measured to be $$(1.1 pm 0.4 pm 0.2)times 10^{-3}$$, where the first uncertainty is statistical and the second is systematic. The 90% credibility level upper limits on $${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}^{'0})$$ and $${cal B}(B^{-} to bar{Lambda}_{c}^{-} Xi_{c}(2645)^{0})$$ are determined to be $$6.5times 10^{-4}$$ and $$7.9times 10^{-4}$$, respectively.

口頭

J-PARCとBelleでのバリオン分光

谷田 聖

no journal, , 

J-PARCおよびBelle実験におけるバリオン分光実験の現状と、将来の見通しについて議論する。

口頭

ハドロン分光; 理論と実験が協力したデータ解析の提案

谷田 聖

no journal, , 

最近、実験データはとみに複雑となり、その解析は実験家だけの手には余るようになってきた。その問題点を指摘し、理論と実験が一体となったデータ解析について提案する。

口頭

Hyperon spectroscopy using hyp-TPC

谷田 聖

no journal, , 

I will discuss possibility of hyperon spectroscopy using hyp-TPC at the extended Hadron Experimental Facility of J-PARC.

口頭

Baryon spectroscopy at J-PARC

谷田 聖

no journal, , 

J-PARC is a multipurpose facility devoted to various fields of science including hadron and nuclear physics. Utilizing its high intensity secondary meson beams, several experiments on baryon spectroscopy were performed and planned. I will show the results of recent experiments and introduce new experiments under preparation.

口頭

Search for a new narrow $$Lambda^*$$ resonance near the $$Lambda eta$$ threshold at J-PARC

谷田 聖

no journal, , 

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 proposed a definitive experiment for $$K^- p to Lambda eta$$, using the newly built hyp-TPC detector to establish the existence of the proposed narrow $$Lambda(1665)$$ and determine its spin and parity in two weeks of beamtime at J-PARC (E72), and obtained (scientific) stage-1 approval. We will discuss these evidences for the proposed $$Lambda^*$$ resonance and introduce the E72 experiment.

口頭

$$Lambda to p pi^-$$崩壊のasymmetry parameter $$alpha$$についてのコメント

谷田 聖

no journal, , 

$$Lambda to p pi^-$$崩壊のasymmetry parameter $$alpha$$について、BESIII実験が数十年ぶりに新しい測定値を報告したが、その値は昔から知られている値よりも20%ほど大きい。もしこれが本当だとすれば、非常に多くの実験・理論が影響を受けることとなるので、昔の測定について調べてみたところ、おそらく間違っているということがわかった。この講演ではどこに間違いがあるのかを報告し、新しい実験を行うことを提案したい。

口頭

$$Lambda_c(2765)$$の量子数の決定

谷田 聖; Belle Collaboration*

no journal, , 

Belle実験における$$Lambda_c(2765)$$の量子数(スピン, パリティ, アイソスピン)の測定について講演する。

口頭

Measurement of spin-parity of charm baryon

谷田 聖

no journal, , 

Spin-parity is essential information to understand the structures of charmed baryons, but experimentally there are few measurements yet. In this talk, I will discuss the latest status of spin-parity determination of charmed baryons.

口頭

Experiments at J-PARC with the new HypTPC detector

谷田 聖

no journal, , 

I will introduce 3 planned experiments at J-PARC with the newly developed HypTPC detector.

口頭

$$Lambda_c to Lambda eta pi^+$$崩壊による分岐比と$$Lambda(1670)$$の測定

谷田 聖; Belle Collaboration*

no journal, , 

本講演では、Belle実験で測定した$$Lambda_c$$バリオンから$$Lambda eta pi^+$$, $$Sigma^0 eta pi^+$$, $$Sigma(1385)^+ eta$$、そして$$Lambda(1670) pi^+$$へ崩壊する分岐比を報告する。このうち、$$Sigma^0 eta pi^+$$$$Lambda(1670) pi^+$$への崩壊は初めて観測されたものである。また、$$Lambda(1670)$$については、質量と幅も同時に決定したので、これについても併せて報告する。

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