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論文

Measurement of $$J/psi$$ at forward and backward rapidity in $$p$$+$$p$$, $$p$$$$+A$$l, $$p$$$$+A$$u, and $$^3$$He+Au collisions at $$sqrt{s_{_{NN}}}$$ = 200 GeV

Acharya, U.*; 長谷川 勝一; 今井 憲一*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他358名*

Physical Review C, 102(1), p.014902_1 - 014902_23, 2020/07

https://doi.org/10.1103/PhysRevC.102.014902
 被引用回数：0 パーセンタイル：100(Physics, Nuclear)

Charmonium is a valuable probe in heavy-ion collisions to study the properties of the quark gluon plasma, and is also an interesting probe in small collision systems to study cold nuclear matter effects, which are also present in large collision systems. With the recent observations of collective behavior of produced particles in small system collisions, measurements of the modification of harmonium in small systems have become increasingly relevant. We present the results of $$J/psi$$ measurements at forward and backward rapidity in various small collision systems, $$p$$$$+$$$$p$$, $$p$$$$+$$Al, $$p$$$$+$$Au and $$^3$$He$$+$$Au, at $$sqrt{s_{_{NN}}}$$=200 GeV. The results are presented in the form of the observable $$R_{AB}$$, the nuclear modification factor, a measure of the ratio of the $$J/psi$$ invariant yield compared to the scaled yield in $$p$$$$+$$$$p$$ collisions. We examine the rapidity, transverse momentum, and collision centrality dependence of nuclear effects on $$J/psi$$ production with different projectile sizes $$p$$ and $$^3$$He, and different target sizes Al and Au. The modification is found to be strongly dependent on the target size, but to be very similar for $$p$$$$+$$Au and $$^{3}$$He$$+$$Au. However, for 0% - 20% central collisions at backward rapidity, the modification for $$^{3}$$He$$+$$Au is found to be smaller than that for $$p$$$$+$$Au, with a mean fit to the ratio of $$0.89pm0.03$$(stat)$${pm}0.08$$(syst), possibly indicating final state effects due to the larger projectile size.

論文

Search for $$B^0$$ decays to invisible final states ($$+gamma$$) at Belle

Ku, Y.*; 谷田 聖; Belle Collaboration*; 他153名*

Physical Review D, 102(1), p.012003_1 - 012003_9, 2020/07

https://doi.org/10.1103/PhysRevD.102.012003
 被引用回数：0 パーセンタイル：100(Astronomy & Astrophysics)

We report searches for $$B^0torm{invisible}$$ and $$B^0torm{invisible}+gamma$$ decays, where the energy of the photon is required to be larger than 0.5 GeV. These results are obtained from a $$711,{rm fb}^{-1}$$ data sample that contains $$772 times 10^6 Bbar{B}$$ pairs and was collected near the $$Upsilon,(4S)$$ resonance with the Belle detector at the KEKB $$e^+ e^-$$ collider. We observe no significant signal for either decay and set upper limits on their branching fractions at $$90%$$ confidence level of $$mathcal{B},(B^0torm{invisible}) < 7.8times10^{-5}$$ and $$mathcal{B},(B^0torm{invisible}+gamma) < 1.6times10^{-5}$$.

論文

Dalitz analysis of $$D^{0}to K^{-}pi^{+}eta$$ decays at Belle

Chen, Y. Q.*; 谷田 聖; Belle Collaboration*; 他181名*

Physical Review D, 102(1), p.012002_1 - 012002_12, 2020/07

https://doi.org/10.1103/PhysRevD.102.012002
 被引用回数：0 パーセンタイル：100(Astronomy & Astrophysics)

We present the results of the first Dalitz plot analysis of the decay $$D^{0}to K^{-}pi^{+}eta$$. The analysis is performed on a data set corresponding to an integrated luminosity of 953 $$rm{fb}^{-1}$$ collected by the Belle detector at the asymmetric-energy $$e^{+}e^{-}$$ KEKB collider. The Dalitz plot is well described by a combination of the six resonant decay channels $$bar{K}^{*}(892)^0eta$$, $$K^{-}a_0(980)^+$$, $$K^{-}a_2(1320)^+$$, $$bar{K}^{*}(1410)^0eta$$, $$K^{*}(1680)^-pi^{+}$$ and $$K_2^{*}(1980)^-pi^{+}$$, together with $$Kpi$$ and $$Keta$$ S-wave components. The decays $$K^{*}(1680)^{-}to K^{-}eta$$ and $$K_{2}^{*}(1980)^{-}to K^{-}eta$$ are observed for the first time. We measure ratio of the branching fractions, $$frac{mathcal{B}(D^{0}to K^{-}pi^{+}eta)}{mathcal{B}(D^{0}to K^{-}pi^{+})}=0.500 pm 0.002 {rm(stat)} pm0.020 {rm(syst)}pm 0.003 {rm (mathcal{B}_{PDG})}$$. Using the Dalitz fit result, the ratio $$frac{mathcal{B}(K^{*}(1680) to K eta)}{mathcal{B}(K^{*}(1680)to Kpi)}$$ is measured to be $$0.11 pm 0.02 {rm(stat)}^{+0.06}_{-0.04}{rm(syst)} pm 0.04{rm(mathcal{B}_{{PDG}})}$$; this is much lower than the theoretical expectations ($$approx 1$$) made under the assumption that $$K^{*}(1680)$$ is a pure $$1^{3}D_1$$ state. The product branching fraction $$mathcal{B}(D^0 to [K_2^{*}(1980)^- to K^{-} eta] pi^{+}) = (2.2^{+1.7}_{-1.9})times10^{-4}$$ is determined. In addition, the $$pieta^{prime}$$ contribution to the $$a_0(980)^{pm}$$ resonance shape is confirmed with 10.1$$sigma$$ statistical significance using the three-channel Flatte model. We also measure $$mathcal{B}(D^0tobar{K}^{*}(892)^0eta)=(1.41^{+0.13}_{-0.12})%$$. This is consistent with, and more precise than, the current world average $$(1.02pm0.30)%$$, deviates with a significance of more than $$3sigma$$ from the theoretical predictions of (0.51-0.92)%.

論文

Roper-like resonances with various flavor contents and their two-pion emission decays

Arifi, A. J.*; 永廣 秀子*; 保坂 淳; 谷田 聖

Physical Review D, 101(11), p.111502_1 - 111502_5, 2020/06

https://doi.org/10.1103/PhysRevD.101.111502
 被引用回数：1 パーセンタイル：37.09(Astronomy & Astrophysics)

We study the three-body decay of the newly observed bottom baryon $$Lambda_b^*(6072)$$ by LHCb; $$Lambda_b^*(6072) to Lambda_b pi pi$$. Its mass about 500 MeV above the ground state $$Lambda_b$$ and a broad width imply that the state could be an analogue of the Roper resonance of the nucleon $$N(1440)$$. In terms of sequential processes going through $$Sigma_b$$ and $$Sigma_b^*$$, we find that the observed invariant mass distribution is reproduced assuming its spin and parity $$J^P = 1/2^+$$. We discuss that the ratio of the two sequential processes and angular correlation of two pions are useful for the determination of spin and parity. We suggest further studies for the Roper resonance analogue in various flavor contents, raising an interesting and important question in baryon spectroscopy.

論文

Transverse single-spin asymmetry for very forward neutral pion production in polarized $$p+p$$ collisions at $$sqrt{s}$$ = 510 GeV

Kim, M. H.*; 谷田 聖; RHICf Collaboration*; 他23名*

Physical Review Letters, 124(25), p.252501_1 - 252501_6, 2020/06

https://doi.org/10.1103/PhysRevLett.124.252501
 被引用回数：0 パーセンタイル：100(Physics, Multidisciplinary)

Transverse single-spin asymmetries of very forward neutral pions generated in polarized $$p + p$$ collisions allow us to understand the production mechanism in terms of perturbative and non-perturbative strong interactions. During 2017 the RHICf Collaboration installed an electromagnetic calorimeter in the zero-degree region of the STAR detector at the Relativistic Heavy Ion Collider (RHIC) and measured neutral pions produced at pseudorapidity larger than 6 in polarized $$p$$+$$p$$ collisions at $$sqrt{s}$$ = 510 GeV. The large non-zero asymmetries increasing both in longitudinal momentum fraction $$x_{F}$$ and transverse momentum $$p_{T}$$ have been observed at low transverse momentum $$p_{T} < 1$$ GeV/$$c$$ for the first time at this collision energy. The asymmetries show an approximate $$x_{F}$$ scaling in the $$p_{T}$$ region where non-perturbative processes are expected to dominate. A non-negligible contribution from soft processes may be necessary to explain the nonzero neutral pion asymmetries.

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

https://doi.org/10.1007/JHEP05(2020)034
 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

Update of inclusive cross sections of single and pairs of identified light charged hadrons

Seidl, R.*; 谷田 聖; Belle Collaboration*; 他136名*

Physical Review D, 101(9), p.092004_1 - 092004_13, 2020/05

https://doi.org/10.1103/PhysRevD.101.092004
 被引用回数：0 パーセンタイル：100(Astronomy & Astrophysics)

We report new measurements of the production cross sections of pairs of charged pions and kaons as a function of their fractional energies using various fractional-energy definitions. Two different fractional-energy definitions were used and compared to the conventional fractional-energy definition reported previously. The new variables aim at either identifying dihadron cross sections in terms of single-hadron fragmentation functions, or to provide a means of characterizing the transverse momentum created in the fragmentation process. The results were obtained applying the updated initial-state radiation correction used in other recent Belle publications on light-hadron production cross sections. In addition, production cross sections of single charged pions, kaons, and protons were also updated using this initial-state radiation correction. The cross sections are obtained from a 558 fb$$^{-1}$$ data sample collected at the $$Upsilon(4S)$$ resonance with the Belle detector 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

https://doi.org/10.1103/PhysRevD.101.091101
 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

https://doi.org/10.1103/PhysRevD.101.094023
 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

Search for an invisibly decaying $$Z^{prime}$$ boson at Belle II in $$e^+ e^- to mu^+ mu^- (e^{pm} mu^{mp})$$ plus missing energy final states

足立 一郎*; 谷田 聖; Belle II Collaboration*; 他358名*

Physical Review Letters, 124(14), p.141801_1 - 141801_9, 2020/04

https://doi.org/10.1103/PhysRevLett.124.141801
 被引用回数：4 パーセンタイル：6.76(Physics, Multidisciplinary)

Theories beyond the standard model often predict the existence of an additional neutral boson, the $$Z^{prime}$$. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a $$Z^{prime}$$ in the process $$e^+ e^- to mu^+ mu^- Z^{prime}$$ and of a lepton-flavor-violating $$Z^{prime}$$ in $$e^+ e^- to e^{pm} mu^{mp} Z^{prime}$$. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an $$L_{mu}-L_{tau}$$ theory, into upper limits on the $$Z^{prime}$$ coupling constant at the level of $$5 times 10^{-2}$$ - $$1$$ for $$M_{Z^prime}leq 6$$ GeV/$$c^2$$.

論文

Measurement of $$mathcal{R}(D)$$ 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：3 パーセンタイル：12.53(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 $$ell$$ 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 $$mathcal{R}(D)$$ and $$mathcal{R}(D^*)$$, based on a data sample containing $$772 times 10^6$$ $$Bbar{B}$$ events recorded at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB $$e^+ e^-$$ collider. In this analysis the tag-side $$B$$ meson is reconstructed in a semileptonic decay mode and the signal-side $$tau$$ is reconstructed in a purely leptonic decay. The measured values are $$mathcal{R}(D)= 0.307 pm 0.037 pm 0.016$$ 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 $$0.2$$, $$1.1$$ and $$0.8$$ standard deviations for $$mathcal{R}(D)$$, $$mathcal{R}(D^*)$$ and their combination, respectively. This work constitutes the most precise measurements of $$mathcal{R}(D)$$ and $$mathcal{R}(D^*)$$ performed to date as well as the first result for $$mathcal{R}(D)$$ based on a semileptonic tagging method.

論文

Nuclear-modification factor of charged hadrons at forward and backward rapidity in $$p+$$Al and $$p+$$Au collisions at $$sqrt{s_{_{NN}}}=200$$ GeV

Aidala, C.*; 長谷川 勝一; 今井 憲一*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他297名*

Physical Review C, 101(3), p.034910_1 - 034910_16, 2020/03

https://doi.org/10.1103/PhysRevC.101.034910
 被引用回数：2 パーセンタイル：27.79(Physics, Nuclear)

The PHENIX experiment has studied nuclear effects in $$p$$$$+$$Al and $$p$$$$+$$Au collisions at $$sqrt{s_{_{NN}}}=200$$ GeV on charged hadron production at forward rapidity ($$1.4< eta < 2.4$$, $$p$$-going direction) and backward rapidity ($$-2.2 < eta < -1.2$$, $$A$$-going direction). Such effects are quantified by measuring nuclear modification factors as a function of transverse momentum and pseudorapidity in various collision multiplicity selections. In central $$p$$$$+$$Al and $$p$$$$+$$Au collisions, a suppression (enhancement) is observed at forward (backward) rapidity compared to the binary scaled yields in $$p$$+$$p$$ collisions. The magnitude of enhancement at backward rapidity is larger in $$p$$$$+$$Au collisions than in $$p$$$$+$$Al collisions, which have a smaller number of participating nucleons. However, the results at forward rapidity show a similar suppression within uncertainties. The results in the integrated centrality are compared with calculations using nuclear parton distribution functions, which show a reasonable agreement at the forward rapidity but fail to describe the backward rapidity enhancement.

論文

$$J/psi$$ and $$psi(2S)$$ production at forward rapidity in $$p$$+$$p$$ collisions at $$sqrt{s}=510$$ GeV

Acharya, U. A.*; 長谷川 勝一; 今井 憲一*; 永宮 正治*; 佐甲 博之; 佐藤 進; 谷田 聖; PHENIX Collaboration*; 他353名*

Physical Review D, 101(5), p.052006_1 - 052006_13, 2020/03

https://doi.org/10.1103/PhysRevD.101.052006
 被引用回数：0 パーセンタイル：100(Astronomy & Astrophysics)

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the differential cross section, mean transverse momentum, mean transverse momentum squared of inclusive $$J/psi$$ and cross-section ratio of $$psi(2S)$$ to $$J/psi$$ at forward rapidity in $$pp$$ collisions at $$sqrt{s} = 510$$ GeV via the dimuon decay channel. Comparison is made to inclusive $$J/psi$$ cross sections measured at $$sqrt{s} = 200$$ GeV and 2.76 - 13 TeV. The result is also compared to leading-order nonrelativistic QCD calculations coupled to a color-glass-condensate description of the low-$$x$$ gluons in the proton at low transverse momentum ($$p_T$$) and to next-to-leading order nonrelativistic QCD calculations for the rest of the $$p_T$$ range. These calculations overestimate the data at low $$p_T$$. While consistent with the data within uncertainties above $$approx 3$$ GeV/$$c$$, the calculations are systematically below the data. The total cross section times the branching ratio is BR $$dsigma^{J/psi}_{pp}/dy (1.2 < |y| < 2.2, 0 < p_T < 10$$ GeV/$$c$$) = 54.3 $$pm$$ 0.5 (stat) $$pm$$ 5.5 (syst) nb.

論文

Study of $$B to p {bar p} pi pi$$

Chu, K.*; 谷田 聖; Belle Collaboration*; 他176名*

Physical Review D, 101(5), p.052012_1 - 052012_8, 2020/03

https://doi.org/10.1103/PhysRevD.101.052012
 被引用回数：0 パーセンタイル：100(Astronomy & Astrophysics)

Using a data sample of $$772 times 10^6$$ BB pairs collected on the $${Upsilon}(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider, we report the observations of $$B^0to p{bar p}pi^+pi^-$$ and $$B^+ to p{bar p}pi^+pi^0$$. We measure a decay branching fraction of $$(0.83 pm 0.17 pm 0.17) times 10^-6$$ in $$B^0to p{bar{p}}pi^+pi^-$$ for $$M_{pi^+pi^-} < 1.22 GeV/c^2$$ with a significance of 5.5 standard deviations. The contribution from $$B0 to p{bar p}K^0$$ is excluded. We measure a decay branching fraction of $$(4.58 pm 1.17 pm 0.67) times 10^-6$$ for $$B^+ to p{bar p}pi^+pi^0$$ with $$M_{pi^+pi^0} < 1.3 GeV/c^2$$ with a significance of 5.4 standard deviations. We study the difference of the $$M_{p{bar p}}$$ distributions in $$B^0to p{bar p}pi^+pi^-$$ and $$B^+ to p{bar p}pi^+pi^0$$.

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

https://doi.org/10.1103/PhysRevLett.124.122001
 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

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

Abudin$'e$n, 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：3 パーセンタイル：11.68(Physics, Nuclear)

From April to July 2018, a data sample at the peak energy of the $$Upsilon(4S)$$ 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 ($$496.3 pm 0.3 pm 3.0$$) 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

Erratum; The Belle II physics book

Kou, E.*; 谷田 聖; Belle II Collaboration*; 他537名*

Progress of Theoretical and Experimental Physics (Internet), 2020(2), p.029201_1 - 029201_6, 2020/02

https://doi.org/10.1093/ptep/ptaa008
 被引用回数：8 パーセンタイル：0.48(Physics, Multidisciplinary)

In the original version of this manuscript, an error was introduced on pp.352. "2.7nb:1.6nb" has been corrected to "2.4nb:1.3nb" in the current online and printed version.

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

https://doi.org/10.1103/PhysRevD.100.112010
 被引用回数：0 パーセンタイル：100(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.

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

https://doi.org/10.1103/PhysRevD.100.111103
 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

The Belle II physics book

Kou, E.*; 谷田 聖; Belle II Collaboration*; 他537名*

Progress of Theoretical and Experimental Physics (Internet), 2019(12), p.123C01_1 - 123C01_654, 2019/12

https://doi.org/10.1093/ptep/ptz106
 被引用回数：48 パーセンタイル：0.26(Physics, Multidisciplinary)

We present the physics program of the Belle II experiment, located on the intensity frontier SuperKEKB $$e^+e^-$$ collider. Belle II collected its first collisions in 2018, and is expected to operate for the next decade. It is anticipated to collect 50/ab of collision data over its lifetime. This book is the outcome of a joint effort of Belle II collaborators and theorists through the Belle II theory interface platform (B2TiP), an effort that commenced in 2014. The aim of B2TiP was to elucidate the potential impacts of the Belle II program, which includes a wide scope of physics topics: B physics, charm, tau, quarkonium, electroweak precision measurements and dark sector searches. It is composed of nine working groups (WGs), which are coordinated by teams of theorist and experimentalists conveners: Semileptonic and leptonic B decays, Radiative and Electroweak penguins, $$phi_1$$ and $$phi_2$$ (time-dependent CP violation) measurements, $$phi_3$$ measurements, Charmless hadronic B decay, Charm, Quarkonium(-like), tau and low-multiplicity processes, new physics and global fit analyses. This book highlights "golden- and silver-channels", i.e. those that would have the highest potential impact in the field. Theorists scrutinised the role of those measurements and estimated the respective theoretical uncertainties, achievable now as well as prospects for the future. Experimentalists investigated the expected improvements with the large dataset expected from Belle II, taking into account improved performance from the upgraded detector.

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