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論文

A Preliminary result on time-reversal invariance violation in polarized neutron transmission through polarized $^{139}$ La

中部倫太郎; 遠藤駿典; 神原理*; 木村敦; 小林龍珠; 奥隆之; 酒井健二; 篠原武尚; 高橋竜太*; 土川雄介; et al.

JPS Conference Proceedings (Internet), 45, p.011066_1 - 011066_5, 2026/06

https://doi.org/10.7566/JPSCP.45.011066

本研究では、横偏極した $^{139}$ La中を伝播する偏極中性子を用いた過去の中性子透過データに基づき、時間反転対称性の破れを評価した。精密なスピン観測量および散乱振幅を解析に取り入れることにより、時間反転対称性を破る断面積に対して予備的な制限を与えた。

論文

Measurement of branching fractions of $Lambda_c^+to{}pK_S^0K_S^0$ and $Lambda_c^+to{}pK_S^0eta$ at Belle

Li, L. K.*; 谷田聖; Belle Collaboration*; 他204名*

Physical Review D, 107(3), p.032004_1 - 032004_9, 2023/02

https://doi.org/10.1103/PhysRevD.107.032004

被引用回数：10 パーセンタイル：64.85(Astronomy & Astrophysics)

We present a study of a singly Cabibbo-suppressed decay $Lambda_c^+to{}pK_S^0K_S^0$ and a Cabibbo-favored decay $Lambda_c^+to{}pK_S^0eta$ based on 980 $rm fb^{-1}$ of data collected by the Belle detector, operating at the KEKB energy-asymmetric collider. We measure their branching fractions relative to $Lambda_c^+to{}pK_S^0$ : $mathcal{B}(Lambda_c^+to{}pK_S^0K_S^0)/mathcal{B}(Lambda_c^+to{}pK_S^0)={(1.48 pm 0.08 pm 0.04)times 10^{-2}}$ and $mathcal{B}(Lambda_c^+to{}pK_S^0eta)/mathcal{B}(Lambda_c^+to{}pK_S^0)={(2.73pm 0.06pm 0.13)times 10^{-1}}$ . Combining with the world average $mathcal{B}(Lambda_c^+to{}pK_S^0)$ , we have the absolute branching fractions: $mathcal{B}(Lambda_c^+to{}pK_S^0K_S^0) = {(2.35pm 0.12pm 0.07 pm 0.12 )times 10^{-4}}$ and $mathcal{B}(Lambda_c^+to{}pK_S^0eta) = {(4.35pm 0.10pm 0.20 pm 0.22 )times 10^{-3}}$ . The first and second uncertainties are statistical and systematic, respectively, while the third ones arise from the uncertainty on $mathcal{B}(Lambda_c^+to{}pK_S^0)$ . The mode $Lambda_c^+to{}pK_S^0K_S^0$ is observed for the first time and has a statistical significance of . The branching fraction of $Lambda_c^+to{}pK_S^0eta$ has been measured with a threefold improvement in precision over previous results and is found to be consistent with the world average.

論文

Search for the decay

Pang, T.*; 谷田聖; Belle Collaboration*; 他206名*

Physical Review D, 106(5), p.L051103_1 - L051103_8, 2022/09

https://doi.org/10.1103/PhysRevD.106.L051103

被引用回数：1 パーセンタイル：7.66(Astronomy & Astrophysics)

We report the results of the first search for the decay using $121.4,{rm fb}^{-1}$ of data collected at the resonance with the Belle detector at the KEKB asymmetric-energy collider. We observe no signal and set a 90% confidence-level upper limit of $8.16 times 10^{-6}$ on the branching fraction.

論文

Search for $Z^{'} rightarrow mu^{+} mu^{-}$ in the $L_mu {-} L_tau$ gauge-symmetric model at Belle

Czank, T.*; 谷田聖; Belle Collaboration*; 他209名*

Physical Review D, 106(1), p.012003_1 - 012003_10, 2022/07

https://doi.org/10.1103/PhysRevD.106.012003

被引用回数：13 パーセンタイル：58.86(Astronomy & Astrophysics)

We search for a new gauge boson that couples only to heavy leptons and their corresponding neutrinos in the process $e^{+} e^{-} rightarrow Z'(rightarrow mu^{+}mu^{-}) mu^{+}mu^{-}$ , using a 643 fb $^{-1}$ data sample collected by the Belle experiment at or near the resonances at the KEKB collider. For the first time, effects due to initial state radiation are used in estimating the detection efficiency. No signal is observed in the mass range of 0.212 $- 10 GeV/${it c}^2$$ and we set an upper limit on the coupling strength, , constraining as a possible contributor to the anomalous magnetic dipole moment of muon.

論文

First test of Lepton Flavor Universality in the charmed baryon decays $Omega^{0}_{c} to Omega^{-} ell^{+} nu_{ell}$ using data of the Belle experiment

Li, Y. B.*; 谷田聖; Belle Collaboration*; 他203名*

Physical Review D, 105(9), p.L091101_1 - L091101_7, 2022/05

https://doi.org/10.1103/PhysRevD.105.L091101

被引用回数：16 パーセンタイル：70.86(Astronomy & Astrophysics)

We present the first observation of the $Omega_{c}^{0} to Omega^{-} mu^{+} nu_{mu}$ decay and present measurements of the branching fraction ratios of the $Omega_{c}^{0} to Omega^{-} ell^{+} nu_{ell}$ decays compared to the reference mode $Omega_{c}^{0} to Omega^{-} pi^+$ , ( or ). This analysis is based on 89.5 fb $^{-1}$ , 711 fb $^{-1}$ , and 121.1 fb $^{-1}$ data samples collected with the Belle detector at the KEKB asymmetric-energy collider at the center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.86 GeV, respectively. The $Omega_{c}^{0}$ signal yields are extracted by fitting $M_{Omega^{-} ell^{+}}$ and $M_{Omega^{-}pi^+}$ spectra. The branching fraction ratios ${cal B}(Omega_{c}^{0} to Omega^{-} e^{+} nu_{e})/{cal B}(Omega_{c}^{0} to Omega^{-} pi^+)$ and ${cal B}(Omega_{c}^{0} to Omega^{-} mu^{+} nu_{mu})/{cal B}(Omega_{c}^{0} to Omega^{-} pi^+)$ are measured to be and , respectively. The ratio of ${cal B}(Omega_{c}^{0} to Omega^{-} e^{+} nu_{e})/{cal B}(Omega_{c}^{0} to Omega^{-} mu^{+} nu_{mu})$ is measured to be , which is consistent with the expectation of lepton flavor universality.

論文

Search for tetraquark states $X_{ccbar{s}bar{s}}$ in $D_{s}^{+}D_{s}^{+}~(D_{s}^{+}D_{s}^{+})$ final states at Belle

Gao, X. Y.*; 谷田聖; Belle Collaboration*; 他207名*

Physical Review D, 105(3), p.032002_1 - 032002_12, 2022/02

https://doi.org/10.1103/PhysRevD.105.032002

被引用回数：12 パーセンタイル：58.86(Astronomy & Astrophysics)

A search for double-heavy tetraquark state candidates $X_{ccbar{s}bar{s}}$ decaying to $D_{s}^{+}D_{s}^{+}$ and $D_{s}^{*+} D_{s}^{*+}$ is presented for the first time using the data samples of 102 million and 158 million events, and the data samples at = 10.52~GeV, 10.58~GeV, and 10.867~GeV corresponding to integrated luminosities of 89.5~fb $^{-1}$ , 711.0~fb $^{-1}$ , and 121.4~fb $^{-1}$ , respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. The invariant-mass spectra of the $D_{s}^{+}D_{s}^{+}$ and $D_{s}^{*+} D_{s}^{*+}$ are studied to search for possible resonances. No significant signals are observed, and the 90% confidence level upper limits on the product branching fractions [ ${cal B}(Upsilon(1S,2S) to X_{ccbar{s}bar{s}} + anything) times {cal B}(X_{ccbar{s}bar{s}} to D_{s}^{+}D_{s}^{+}(D_{s}^{*+} D_{s}^{*+}))$ ] in inclusive decays and the product values of Born cross section and branching fraction [ $sigma(e^+e^- to X_{ccbar{s}bar{s}} + anything ) times {cal B}(X_{ccbar{s}bar{s}} to D_{s}^{+}D_{s}^{+}(D_{s}^{*+} D_{s}^{*+}))$ ] in collisions at = 10.52~GeV, 10.58~GeV, and 10.867~GeV under different assumptions of $X_{ccbar{s}bar{s}}$ masses and widths are obtained.

論文

Study of $overline{B}{}^0rightarrow D^{+}h^{-} (h=K/pi)$ decays at Belle

Waheed, E.*; 谷田聖; Belle Collaboration*; 他205名*

Physical Review D, 105(1), p.012003_1 - 012003_9, 2022/01

https://doi.org/10.1103/PhysRevD.105.012003

被引用回数：5 パーセンタイル：34.00(Astronomy & Astrophysics)

We present a measurement of the branching fractions of the Cabibbo favored $overline{B}{}^0rightarrow D^{+}pi^{-}$ and the Cabibbo suppressed $overline{B}{}^0rightarrow D^{+}K^{-}$ decays. We find $mathcal{B}(overline{B}{}^0rightarrow D^{+}pi^{-}) = (2.48 pm 0.01 pm 0.09 pm 0.04) times 10^{-3}$ and $mathcal{B}(overline{B}{}^0rightarrow D^{+}K^{-})= (2.03 pm 0.05 pm 0.07 pm 0.03) times 10^{-4}$ decays, where the first uncertainty is statistical, the second is systematic, and the third uncertainty is due to the $D^{+} rightarrow K^{-}pi^{+}pi^{+}$ branching fraction. The ratio of branching fractions of $overline{B}{}^0rightarrow D^{+}K^{-}$ and $overline{B}{}^0rightarrow D^{+}pi^{-}$ is measured to be $R^{D} = [8.19 pm 0.20(rm stat) pm 0.23(rm syst)] times 10^{-2}$ . These measurements are performed using the full Belle data set, which corresponds to $772 times 10^{6} Boverline{B}$ pairs.

論文

Measurements of moments of inclusive $B rightarrow X_c ell^+ nu_{ell}$ decays with hadronic tagging

van Tonder, R.*; 谷田聖; Belle Collaboration*; 他202名*

Physical Review D, 104(11), p.112011_1 - 112011_32, 2021/12

AA2022-0102.pdf:4.42MB

https://doi.org/10.1103/PhysRevD.104.112011

被引用回数：22 パーセンタイル：71.29(Astronomy & Astrophysics)

We present the measurement of the first to fourth order moments of the four-momentum transfer squared, , of inclusive $B rightarrow X_c ell^+ nu_{ell}$ decays using the full Belle data set of 711 $mathrm{fb}^{-1}$ of integrated luminosity at the resonance where . The determination of these moments and their systematic uncertainties open new pathways to determine the absolute value of the CKM matrix element $V_{cb}$ using a reduced set of matrix elements of the heavy quark expansion. In order to identify and reconstruct the system, we reconstruct one of the two -mesons using machine learning techniques in fully hadronic decay modes. The moments are measured with progressively increasing threshold selections on starting with a lower value of 3.0 $mathrm{GeV}^2$ in steps of 0.5 $mathrm{GeV}^2$ up to a value of 10.0 $mathrm{GeV}^2$ . The measured moments are further unfolded, correcting for reconstruction and selection effects as well as QED final state radiation. We report the moments separately for electron and muon final states and observe no lepton flavor universality violating effects.

論文

Measurement of the masses and widths of the and baryons

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

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

https://doi.org/10.1103/PhysRevD.104.052003

被引用回数：8 パーセンタイル：40.06(Astronomy & Astrophysics)

Using 980 ${rm fb}^{-1}$ of data with the Belle detector operating at the KEKB asymmetric-energy collider, we report the measurements of the masses, and the first measurements of the instrinsic widths, of the and 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 states.

論文

Search for the $eta_{c2}(1D)$ in $e^+e^-togammaeta_{c2}(1D)$ at 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

https://doi.org/10.1103/PhysRevD.104.012012

被引用回数：3 パーセンタイル：10.97(Astronomy & Astrophysics)

For the first time we search for the $eta_{c2}(1D)$ in $e^+e^-togammaeta_{c2}(1D)$ at = 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/. 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 near 10.6 GeV.

論文

Measurement of branching fractions and asymmetries for $D_s^{+} rightarrow K^+ (eta, pi^0)$ and $D_s^{+} rightarrow pi^+ (eta, pi^0)$ decays at Belle

Guan, Y.*; 谷田聖; Belle Collaboration*; 他202名*

Physical Review D, 103(11), p.112005_1 - 112005_11, 2021/06

AA2022-0156.pdf:1.04MB

https://doi.org/10.1103/PhysRevD.103.112005

被引用回数：6 パーセンタイル：31.77(Astronomy & Astrophysics)

We report measurements of the branching fractions and asymmetries for $D_s^{+} rightarrow K^{+} eta$ , $D_s^{+} rightarrow K^{+} pi^0$ , and $D_s^{+} rightarrow pi^{+} eta$ decays, and the branching fraction for $D_s^{+} rightarrow pi^{+} pi^0$ . Our results are based on a data sample corresponding to an integrated luminosity of 921 fb $^{-1}$ collected by the Belle detector at the KEKB asymmetric-energy collider. Our measurements of asymmetries in these decays are the most precise to-date; no evidence for violation is found.

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

AA2022-0158.pdf:0.4MB

https://doi.org/10.1103/PhysRevD.103.L111101

被引用回数：27 パーセンタイル：77.86(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 over or , 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 $pm 0.29mathrm{(stat.)}^{ +0.15}_{-0.09}mathrm{(syst.)}$ , where the last uncertainty is due to possible isospin-symmetry-breaking effects. This value favors the spin-parity 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

Measurements of the branching fractions of and decays at Belle

Li, S. X.*; 谷田聖; Belle Collaboration*; 他203名*

Physical Review D, 103(7), p.072004_1 - 072004_9, 2021/04

AA2022-0154.pdf:0.56MB

https://doi.org/10.1103/PhysRevD.103.072004

被引用回数：20 パーセンタイル：69.81(Astronomy & Astrophysics)

We report measurements of the branching fractions of singly Cabibbo-suppressed decays and using the full Belle data sample corresponding to an integrated luminosity of 980.6 $rm fb^{-1}$ . The data were collected by the Belle detector at the KEKB $e^{+}$ $e^{-}$ asymmetric-energy collider. A clear signal is seen in the invariant mass distribution of . The signal yield of the process is ; from this, we measure the ratio of branching fractions ${cal B}(Lambda_c^+ to p eta)/{cal B}(Lambda_c^+ to p K^- pi^+) = (2.258 pm 0. 077(rm stat.) pm 0.136(rm syst.))times 10^{-2}$ , from which we infer the branching fraction ${cal B}(Lambda_c^+ to p eta) = (1.42 pm 0.05(rm stat.) pm 0.11(rm syst.)) times 10^{-3}$ . In addition, no significant signal for is found so an upper limit on the branching fraction of ${cal B}(Lambda_c^+ to p pi^0) < 8.0 times 10^{-5}$ at 90% credibility level is set, more than three times better than the best current upper limit.

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

AA2022-0017.pdf:0.63MB

https://doi.org/10.1103/PhysRevD.103.052005

被引用回数：16 パーセンタイル：62.56(Astronomy & Astrophysics)

We report branching fraction measurements of four decay modes of the $Lambda_{c}^{+}$ baryon, each of which includes an meson and a 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 $mathcal{B}(Lambda_{c}^{+} rightarrow eta Lambda pi^{+})$ / $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = , $mathcal{B}(Lambda_{c}^{+} rightarrow eta Sigma^{0} pi^{+})$ / $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = , $mathcal{B}(Lambda_{c}^{+} rightarrow Lambda(1670) pi^{+}) times mathcal{B}(Lambda(1670) rightarrow etaLambda)$ / $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-} pi^{+})$ = $(5.54 pm 0.29 pm 0.73) times 10^{-2}$ , and $mathcal{B}(Lambda_{c}^{+} rightarrow eta Sigma(1385)^{+})$ / $mathcal{B}(Lambda_{c}^{+} rightarrow p K^{-}pi^{+})$ = . The mass and width of the are also precisely determined to be $1674.3 pm 0.8 pm 4.9~{rm MeV}/c^{2}$ and , respectively, where the uncertainties are statistical and systematic, respectively.

論文

Measurement of time-dependent violation parameters in $B^{0} to K^{0}_{S}K^{0}_{S}K^{0}_{S}$ decays at Belle

Kang, K. H.*; 谷田聖; Belle Collaboration*; 他204名*

Physical Review D, 103(3), p.032003_1 - 032003_8, 2021/02

AA2022-0015.pdf:0.64MB

https://doi.org/10.1103/PhysRevD.103.032003

被引用回数：3 パーセンタイル：16.46(Astronomy & Astrophysics)

We measure the time-dependent violation parameters in $B^{0} to K^{0}_{S}K^{0}_{S}K^{0}_{S}$ decays using pairs collected at the resonance with the Belle detector at the KEKB asymmetric-energy collider. The obtained mixing-induced and direct asymmetries are and , respectively. These values are consistent with the Standard Model predictions. The significance of violation differs from zero by 2.5 standard deviations.

論文

Search for a doubly charged bound state in inclusive decays and via direct production in collisions at = 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

AA2021-0363.pdf:1.76MB

https://doi.org/10.1103/PhysRevD.102.112001

被引用回数：10 パーセンタイル：44.76(Astronomy & Astrophysics)

We report the results of a first search for a doubly-charged bound state, denoted the $R^{++}$ , in and inclusive decays and via direct production in collisions at = 10.520, 10.580, and 10.867 GeV. The search uses data accumulated with the Belle detector at the KEKB asymmetric-energy 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 and 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 collisions ( $sigma(e^+e^- to R^{++} + {rm anything}) times {cal B}(R^{++} to D^{+} D_{s}^{*+})$ ) at = 10.520, 10.580, and 10.867 GeV under different assumptions of $R^{++}$ masses varying from 4.13 to 4.17 GeV/, and widths varying from 0 to 5 MeV are obtained.

論文

Study of electromagnetic decays of orbitally excited Baryons

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

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

https://doi.org/10.1103/PhysRevD.102.071103

被引用回数：20 パーセンタイル：66.91(Astronomy & Astrophysics)

Using 980 fb $^{-1}$ of data collected with the Belle detector operating at the KEKB asymmetric-energy collider, we report a study of the electromagnetic decays of excited and . A clear signal (8.6 standard deviations) is observed for , and we measure: . We also present evidence (3.8 standard deviations) for the similar decay of the 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 and 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

Measurement of and $mathcal{R}(D^*)$ with a semileptonic tagging method

Caria, G.*; 谷田聖; Belle Collaboration*; 他202名*

Physical Review Letters, 124(16), p.161803_1 - 161803_8, 2020/04

https://doi.org/10.1103/PhysRevLett.124.161803

被引用回数：148 パーセンタイル：98.19(Physics, Multidisciplinary)

The experimental results on the ratios of branching fractions $mathcal{R}(D) = {cal B}(bar{B} to D tau^- bar{nu_{tau}})/{cal B}(bar{B} to D ell^- barnu_{ell})$ and $mathcal{R}(D^*) = {cal B}(bar{B} to D^* tau^- bar{nu_{tau}})/{cal B}(bar{B} to D^* ell^- bar{nu_{ell}})$ , where denotes an electron or a muon, show a long-standing discrepancy with the Standard Model predictions, and might hint to a violation of lepton flavor universality. We report a new simultaneous measurement of and $mathcal{R}(D^*)$ , based on a data sample containing events recorded at the resonance with the Belle detector at the KEKB collider. In this analysis the tag-side meson is reconstructed in a semileptonic decay mode and the signal-side is reconstructed in a purely leptonic decay. The measured values are and $mathcal{R}(D^*) = 0.283 pm 0.018 pm 0.014$ , where the first uncertainties are statistical and the second are systematic. These results are in agreement with the Standard Model predictions within , and standard deviations for , $mathcal{R}(D^*)$ and their combination, respectively. This work constitutes the most precise measurements of and $mathcal{R}(D^*)$ performed to date as well as the first result for based on a semileptonic tagging method.

論文

Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment

Abudinn, F.*; 谷田聖; Belle II Collaboration*; 他420名*

Chinese Physics C, 44(2), p.021001_1 - 021001_12, 2020/02

https://doi.org/10.1088/1674-1137/44/2/021001

被引用回数：34 パーセンタイル：90.43(Physics, Nuclear)

From April to July 2018, a data sample at the peak energy of the resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be () pb $^{-1}$ , where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II.

論文

Transverse single spin asymmetry for very forward production in polarized proton-proton collisions at = 510 GeV

Kim, M. H.*; 谷田聖; 他20名*

EPJ Web of Conferences, 208, p.05007_1 - 05007_4, 2019/05

https://doi.org/10.1051/epjconf/201920805007

被引用回数：0 パーセンタイル：0.00(Astronomy & Astrophysics)

Transverse single spin asymmetry, $A_{N}$ , of very forward $pi^{0}$ production from polarized collisions provides new information toward an understanding of its production mechanism. $A_{N}$ of forward $pi^{0}$ in the pseudorapidity region of has been described by the partonic structure of the proton in the perturbative QCD framework. However, recent data indicates a potential contribution from not only partonic but also diffractive interactions. In order to provide a new insight on the origin of the $A_{N}$ , we measured the very forward $pi^{0}$ production in the pseudorapidity region of from = 510 GeV polarized collisions at RHIC in 2017. We report our measurement of the very forward $pi^{0}$ over the transverse momentum range of $0 < p_{T} < 1$ GeV/ and the preliminary result.