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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:1 パーセンタイル:14.11(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

Further signatures to support the tetraquark mixing framework for the two light-meson nonets

Kim, H.*; Kim, K. S.*; Cheoun, M.-K.*; 慈道 大介*; 岡 眞

Physical Review D, 99(1), p.014005_1 - 014005_15, 2019/01

 パーセンタイル:100(Astronomy & Astrophysics)

前回の論文で指摘した、軽いスカラー中間子8重項のテトラクォーク描像に基づく状態混合について、さらなる証拠となる現象の解析を行った。

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:2 パーセンタイル:64.74(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

 パーセンタイル:100(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.

論文

Evidence of a structure in $$bar{K}^{0} Lambda _{c}^{+}$$ consistent with a charged $$Xi _c(2930)^{+}$$, and updated measurement of $$bar{B}^{0} rightarrow bar{K}^{0} Lambda _{c}^{+} bar{Lambda }_{c}^{-}$$ at Belle

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

European Physical Journal C, 78(11), p.928_1 - 928_8, 2018/11

We report evidence for the charged charmed-strange baryon $$Xi_{c}(2930)^+$$ with a signal significance of 3.9$$sigma$$ with systematic errors included. The charged $$Xi_{c}(2930)^+$$ is found in its decay to $$K_{S}^{0} Lambda_{c}^+$$ in the substructure of $$bar{B}^{0} to K^{0}_{S} Lambda_{c}^{+} bar{Lambda}_{c}^{-}$$ decays. The measured mass and width are $$[2942.3 pm 4.4 (rm stat.) pm 1.5(rm syst.)]$$~MeV/$$c^{2}$$ and $$[14.8 pm 8.8(rm stat.) pm 2.5(rm syst.)]$$~MeV, respectively, and the product branching fraction is $${cal B}(bar{B}^{0} to Xi_c(2930)^{+} bar{Lambda}_{c}^{-})$$ $${cal B}(Xi_c(2930)^{+}to bar{K}^{0} Lambda_{c}^{+})=[2.37 pm 0.51 (rm stat.)pm 0.31(rm syst.)]times 10^{-4}$$. We also measure $${cal B}(bar{B}^{0} to bar{K}^{0} Lambda_{c}^{+} bar{Lambda}_{c}^{-}) = [3.99 pm 0.76(rm stat.) pm 0.51(rm syst.)] times 10^{-4}$$ with greater precision than previous experiments, and present the results of a search for the charmonium-like state $$Y(4660)$$ and its spin partner, $$Y_{eta}$$, in the $$Lambda_{c}^{+}bar{Lambda}_{c}^{-}$$ invariant mass spectrum. No clear signals of the $$Y(4660)$$ or $$Y_{eta}$$ are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $$(772pm11)times 10^{6} Bbar{B}$$ pairs collected at the $$Upsilon(4S)$$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.

論文

Observation of $$e^+e^-topi^+pi^-pi^0chi_{b1,2}(1P)$$ and search for $$e^+e^-tophichi_{b1,2}(1P)$$ at $$sqrt{s}$$ = 10.96 - 11.05 GeV

Yin, J. H.*; 谷田 聖; Belle Collaboration*; 他189名*

Physical Review D, 98(9), p.091102_1 - 091102_9, 2018/11

 パーセンタイル:100(Astronomy & Astrophysics)

We report searches for the processes $$e^+e^-topi^+pi^-pi^0chi_{bJ}$$ and $$e^+e^-tophichi_{bJ}$$ (J=1,2) in the vicinity of the $$Upsilon(11020)$$ resonance using energy scan data collected by the Belle experiment at the KEKB collider. We observe $$e^+e^-to pi^+pi^-pi^0chi_{b1}$$ and find evidence for $$e^+e^-to omegachi_{b2}$$ processes for data with center-of-mass energies from 10.96 to 11.05~GeV for the first time. The statistical significance for $$pi^+pi^-pi^0chi_{b1}$$ and $$omegachi_{b2}$$ are $$6.1sigma$$ and $$4.0sigma$$, respectively. We investigate energy dependence of the $$e^+e^-topi^+pi^-pi^0chi_{bJ}$$ cross section and find that it is consistent with production of $$Upsilon(10860)$$ and $$Upsilon(11020)$$ resonances without significant non-resonant contribution. Assuming $$e^+e^-to pi^+pi^-pi^0chi_{bJ}$$ proceeds via $$Upsilon(10860)$$ and $$Upsilon(11020)$$, the branching fraction $$mathcal{B}(Upsilon(11020)topi^+pi^-pi^0chi_{bJ})=(8.6pm4.1pm6.1^{+4.5}_{-2.5})times10^{-3}$$ is measured for the first time, where the first error is statistical, the second is systematic, and the third from the branching fraction of $$Upsilon(11020)to e^+e^-$$. The signals for $$e^+e^-to phichi_{bJ}$$ are not significant, and the upper limits of the Born cross sections at the 90% confidence level are $$0.6$$ and $$1.0$$~pb for $$e^+e^-to phichi_{b1}$$ and $$phichi_{b2}$$, respectively, for center-of-mass energies from 10.96 to 11.05 GeV.

論文

Observation of $$e^+e^- to gamma chi_{c1}$$ and search for $$e^+e^- to gamma chi_{c0}, gamma chi_{c2}$$, and $$gammaeta_c$$ at $$sqrt{s}$$ near 10.6 GeV at Belle

Jia, S.*; 谷田 聖; Belle Collaboration*; 他191名*

Physical Review D, 98(9), p.092015_1 - 092015_8, 2018/11

 パーセンタイル:100(Astronomy & Astrophysics)

Using data samples of 89.5~fb$$^{-1}$$, 711.0~fb$$^{-1}$$, and 121.4~fb$$^{-1}$$ collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.867 GeV, respectively, we study the exclusive reactions $$e^+e^-togammachi_{cJ}$$ ($$J = 0,~1,~2$$) and $$e^+e^-togammaeta_c$$. A significant $$gamma chi_{c1}$$ signal is observed for the first time at $$sqrt{s}=10.58$$ GeV with a significance of $$5.1sigma$$ including systematic uncertainties. No significant excesses for $$gamma chi_{c0}$$, $$gamma chi_{c2}$$, and $$gamma eta_c$$ final states are found, and we set 90% credibility level upper limits on the Born cross sections ($$sigma_{rm B}$$) at 10.52 GeV, 10.58 GeV, and 10.867~GeV. Together with cross sections measured by BESIII at lower center-of-mass energies, the energy dependency of $$sigma_{rm B}(e^+e^-togammachi_{c1})$$ is obtained.

論文

Measurement of $$eta_c(1S)$$, $$eta_c(2S)$$, and nonresonant $$eta' pi^+ pi^-$$ production via two-photon collisions

Xu, Q. N.*; 谷田 聖; Belle Collaboration*; 他176名*

Physical Review D, 98(7), p.072001_1 - 072001_17, 2018/10

 パーセンタイル:100(Astronomy & Astrophysics)

We report the measurement of $$gamma gamma to eta_c(1S)$$, $$eta_c(2S) to eta' pi^+ pi^-$$ with $$eta'$$ decays to $$gamma rho$$ and $$eta pi^+ pi^-$$ using 941 fb$$^{-1}$$ of data collected with the Belle detector at the KEKB asymmetric-energy $$e^+e^-$$ collider. The $$eta_c(1S)$$ mass and width are measured to be $$M = [2984.6pm0.7 (stat.)pm2.2 (syst.)]$$ MeV/$$c^{2}$$ and $$Gamma = [30.8^{+2.3}_{-2.2}~(stat.) pm 2.5~(syst.)]$$ MeV, respectively. First observation of $$eta_c(2S) to eta' pi^+ pi^-$$ with a significance of $$5.5sigma$$ including systematic error is obtained, and the $$eta_c(2S)$$ mass is measured to be $$M = [3635.1pm3.7~(stat.)pm2.9~(syst.)]$$ MeV/$$c^{2}$$. The products of the two-photon decay width and branching fraction $$(B)$$ of decays to $$eta'pi^+ pi^-$$ are determined to be $$Gamma_{gamma gamma}B = [65.4pm2.6~(stat.)pm6.9~(syst.)]$$ eV for $$eta_c(1S)$$ and $$[5.6^{+1.2}_{-1.1}~(stat.)pm1.1~(syst.)]$$ eV for $$eta_c(2S)$$. A new decay mode for the $$eta_c(1S)$$ to $$eta'f_0(2080)$$ with $$f_0(2080) to pi^+ pi^-$$ is observed with a statistical significance of $$20sigma$$. The $$f_0(2080)$$ mass and width are determined to be $$M = [2083^{+63}_{-66}~(stat.)pm 32~(syst.)]$$ MeV/$$c^{2}$$ and $$Gamma = [178^{+60}_{-178}~(stat.) pm 55~(syst.)]$$ MeV. The cross sections for $$gamma gamma to eta' pi^+ pi^-$$ and $$eta'f_{2}(1270)$$ are measured for the first time.

論文

Inclusive study of bottomonium production in association with an $$eta $$ meson in $$e^+e^-$$ annihilations near $$Upsilon (5S)$$

Tamponi, U.*; 谷田 聖; Belle Collaboration*; 他174名*

European Physical Journal C, 78(8), p.633_1 - 633_10, 2018/08

We study bottomonium production in association with an $$eta$$ meson in $$e^+e^-$$ annihilations near the $$Upsilon(5S)$$, at a center of mass energy of $$sqrt{s}=10.866,$$GeV. The results are based on the $$121.4,$$fb$$^{-1}$$ data sample collected by the Belle experiment at the asymmetric energy KEKB collider. Only the $$eta$$ meson is reconstructed and the missing-mass spectrum of $$eta$$ candidates is investigated. We observe the $$e^+e^-toetaUpsilon_J(1D)$$ process and find evidence for the $$e^+e^-toetaUpsilon(2S)$$ process, while no significant signals of $$Upsilon(1S)$$, $$h_b(1P)$$, nor $$h_b(2P)$$ are found. Cross sections for the studied processes are reported.

論文

Observation of an excited $$Omega^-$$ Baryon

Yelton, J.*; 谷田 聖; Belle Collaboration*; 他190名*

Physical Review Letters, 121(5), p.052003_1 - 052003_7, 2018/08

 被引用回数:7 パーセンタイル:6.69(Physics, Multidisciplinary)

Using data recorded with the Belle detector, we observe a new excited hyperon, an $$Omega^{*-}$$ candidate decaying into $$Xi^0K^-$$ and $$Xi^-K^0_S$$ with a mass of $$2012.4pm0.7 {rm (stat)pm 0.6 (rm syst)} {rm MeV}/c^2$$ and a width of $$Gamma=6.4^{+2.5}_{-2.0} {rm(stat)}pm1.6 {rm(syst)} {rm MeV}$$. The $$Omega^{*-}$$ is seen primarily in $$Upsilon(1S), Upsilon(2S)$$, and $$Upsilon(3S)$$ decays.

論文

Observation of $$Upsilon(4S)to eta' Upsilon(1S)$$

Guido, E.*; 谷田 聖; Belle Collaboration*; 他168名*

Physical Review Letters, 121(6), p.062001_1 - 062001_7, 2018/08

 パーセンタイル:100(Physics, Multidisciplinary)

We report the first observation of the hadronic transition $$Upsilon(4S)toeta'Upsilon(1S)$$, using 496 fb$$^{-1}$$ data collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^{+}e^{-}$$ collider. We reconstruct the $$eta'$$ meson through its decays to $$rho^0gamma$$ and to $$pi^+pi^-eta$$, with $$etatogammagamma$$. We measure: $${cal B}(Upsilon(4S)toeta'Upsilon(1S))=(3.43pm 0.88 {rm(stat.)} pm 0.21 {rm(syst.)})times10^{-5}$$, with a significance of 5.7$$sigma$$.

論文

Search for $$Upsilon(1S,2S) to Z^{+}_{c}Z^{(prime) -}_{c}$$ and $$e^{+}e^{-} to Z^{+}_{c}Z^{(prime) -}_{c}$$ at $$sqrt{s}$$ = 10.52, 10.58, and 10.867 GeV

Jia, S.*; 谷田 聖; Belle Collaboration*; 他181名*

Physical Review D, 97(11), p.112004_1 - 112004_16, 2018/06

 パーセンタイル:100(Astronomy & Astrophysics)

The first search for $$Z_{c}$$ pair production in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ decays and in $$e^{+}e^{-}$$ annihilation at $$sqrt{s}$$ = 10.52, 10.58, and 10.867 GeV is conducted using data collected with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant signals are observed in any of the studied modes, and the 90% credibility level upper limits on their product branching fractions in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ decays ($${cal B}(Upsilon(1S,2S)to Z^{+}_{c}Z^{(prime) -}_{c})times{cal B}(Z^{+}_{c}topi^{+}+cbar c)$$ ($$cbar c=J/psi$$, $$chi_{c1}(1P)$$, $$psi(2S)$$)) and the product of Born cross section and branching fraction for $$e^{+}e^{-} to Z^{+}_{c}Z^{(prime) -}_{c}$$ ($$sigma(e^+e^- to Z^{+}_{c}Z^{(prime) -}_{c})times {cal B}(Z^{+}_{c} to pi^+ +cbar c)$$) at $$sqrt{s}$$ = 10.52, 10.58, and 10.867 GeV are determined. Here, $$Z_{c}$$ refers to the $$Z_{c}(3900)$$ and $$Z_{c}(4200)$$ observed in the $$pi J/psi$$ final state, the $$Z_{c1}(4050)$$ and $$Z_{c2}(4250)$$ in the $$pichi_{c1}(1P)$$ state, and the $$Z_{c}(4050)$$ and $$Z_{c}(4430)$$ in the $$pipsi(2S)$$ state.

論文

Tetraquark mixing framework for isoscalar resonances in light mesons

Kim, H.*; Kim, K. S.*; Cheoun, M.-K.*; 岡 眞

Physical Review D, 97(9), p.094005_1 - 094005_17, 2018/05

 被引用回数:5 パーセンタイル:17.57(Astronomy & Astrophysics)

アイソスピン0のスカラー中間子に対して、テトラクォーク描像を用いて、その状態混合の可能性を調べた。その結果を崩壊の解析にも応用した。

論文

Production cross sections of hyperons and charmed baryons from $$e^+e^-$$ annihilation near $$sqrt{s} = 10.52$$ GeV

新山 雅之*; 谷田 聖; Belle Collaboration*; 他167名*

Physical Review D, 97(7), p.072005_1 - 072005_21, 2018/04

 被引用回数:4 パーセンタイル:23.42(Astronomy & Astrophysics)

We measure the inclusive production cross sections of hyperons and charmed baryons from $$e^+e^-$$ annihilation using a 800 fb$$^{-1}$$ data sample taken near the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. The feed-down contributions from heavy particles are subtracted using our data, and the direct production cross sections are presented for the first time. The production cross sections divided by the number of spin states for $$S=-1$$ hyperons follow an exponential function with a single slope parameter except for the $$Sigma(1385)^+$$ resonance. Suppression for $$Sigma(1385)^+$$ and $$Xi(1530)^0$$ hyperons is observed. Among the production cross sections of charmed baryons, a factor of three difference for $$Lambda_c^+$$ states over $$Sigma_c$$ states is observed. This observation suggests a diquark structure for these baryons.

論文

Observation of $$Xi_{c}(2930)^0$$ and updated measurement of $$B^{-} to K^{-} Lambda_{c}^{+} bar{Lambda}_{c}^{-}$$ at Belle

Li, Y. B.*; 谷田 聖; Belle Collaboration*; 他178名*

European Physical Journal C, 78(3), p.252_1 - 252_8, 2018/03

We report the first observation of the $$Xi_{c}(2930)^0$$ charmed-strange baryon with a significance greater than 5$$sigma$$. The $$Xi_{c}(2930)^0$$ is found in its decay to $$K^- Lambda_{c}^+$$ in $$B^{-} to K^{-} Lambda_{c}^{+} bar{Lambda}_{c}^{-}$$ decays. The measured mass and width are $$[2928.9 pm 3.0(rm stat.)^{+0.9}_{-12.0}(rm syst.)]$$ MeV/$$c^{2}$$ and $$[19.5 pm 8.4(rm stat.) ^{+5.9}_{-7.9}(rm syst.)]$$ MeV, respectively, and the product branching fraction is $${cal B}(B^{-} to Xi_{c}(2930)^0 bar{Lambda}_{c}^{-})$$$$ {cal B}(Xi_{c}(2930)^0 to K^- Lambda_{c}^{+})$$=$$[1.73 pm 0.45(rm stat.) pm 0.21(rm syst.)] times 10^{-4}$$. We also measure $${cal B}(B^{-} to K^{-} Lambda_{c}^{+} bar{Lambda}_{c}^{-}) = [4.80 pm 0.43(rm stat.) pm 0.60(rm syst.)] times 10^{-4}$$ with improved precision, and search for the charmonium-like state $$Y(4660)$$ and its spin partner, $$Y_{eta}$$, in the $$Lambda_{c}^{+}bar{Lambda}_{c}^{-}$$ invariant mass spectrum. No clear signals of the $$Y(4660)$$ nor its spin partner are observed and the 90% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $$(772pm11)times 10^{6} Bbar{B}$$ pairs collected at the $$Upsilon(4S)$$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.

論文

Observation of excited $$Omega_c$$ charmed baryons in $$e^+e^-$$ collisions

Yelton, J.*; 谷田 聖; Belle Collaboration*; 他177名*

Physical Review D, 97(5), p.051102_1 - 051102_6, 2018/03

 被引用回数:12 パーセンタイル:3.72(Astronomy & Astrophysics)

Using the entire Belle data sample of 980 $${rm fb}^{-1}$$ of $$e^+e^-$$ collisions, we present the results of a study of excited $$Omega_c$$ charmed baryons in the decay mode $$Xi_c^+K^-$$. We show confirmation of four of the five narrow states reported by the LHCb Collaboration: the $$Omega_c(3000)$$, $$Omega_c(3050)$$, $$Omega_c(3066)$$, and $$Omega_c(3090)$$.

論文

Study of $$K^0_S$$ pair production in single-tag two-photon collisions

増田 正孝*; 谷田 聖; Belle Collaboration*; 他185名*

Physical Review D, 97(5), p.052003_1 - 052003_20, 2018/03

 パーセンタイル:100(Astronomy & Astrophysics)

We report a measurement of the cross section for $$K^0_S$$ pair production in single-tag two-photon collisions, $$gamma^* gamma to K^0_S K^0_S$$, for $$Q^2$$ up to 30 GeV$$^2$$, where $$Q^2$$ is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range 1.0 GeV $$< W <$$ 2.6 GeV and $$|cos theta^*| < 1.0$$ for the total energy and kaon scattering angle, respectively, in the $$gamma^* gamma$$ center-of-mass system. These results are based on a data sample of 759 fb$$^{-1}$$ collected with the Belle detector at the KEKB asymmetric-energy $$e^+ e^-$$ collider. For the first time, the transition form factor of the $$f_2'(1525)$$ meson is measured separately for the helicity-0, -1, and -2 components and also compared with theoretical calculations. Finally, the partial decay widths of the $$chi_{c0}$$ and $$chi_{c2}$$ mesons are measured as a function of $$Q^2$$.

論文

Measurement of branching fractions of hadronic decays of the $$Omega_c^0$$ baryon

Yelton, J.*; 谷田 聖; Belle Collaboration*; 他187名*

Physical Review D, 97(3), p.032001_1 - 032001_8, 2018/02

 被引用回数:1 パーセンタイル:64.74(Astronomy & Astrophysics)

Using a data sample of 980 $${rm fb}^{-1}$$ of $$e^+e^-$$ annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy $$e^+e^-$$ collider, we report the results of a study of the decays of the $$Omega_c^0$$ charmed baryon into hadronic final states. We report the most precise measurements to date of the relative branching fractions of the $$Omega_c^0$$ into $$Omega^-pi^+pi^0$$, $$Omega^-pi^+pi^-pi^+$$, $$Xi^-K^-pi^+pi^+$$, and $$Xi^0K^-pi^+$$, as well as the first measurements of the branching fractions of the $$Omega_c^0$$ into $$Xi^-bar{K}^0pi^+$$, $$Xi^0bar{K}^0$$, and $$Lambda bar{K}^0bar{K}^0$$, all with respect to the $$Omega^-pi^+$$ decay. In addition, we investigate the resonant substructure of these modes. Finally, we present a limit on the branching fraction for the decay $$Omega_c^0toSigma^+K^-K^-pi^+$$.

論文

Search for light tetraquark states in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ decays

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

Physical Review D, 96(11), p.112002_1 - 112002_14, 2017/12

 パーセンタイル:100(Astronomy & Astrophysics)

We search for the $$J^{PC}=0^{--}$$ and $$1^{+-}$$ light tetraquark states with masses up to 2.46~GeV/$$c^2$$ in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ decays with data samples of $$(102pm 2)$$ million and $$(158pm 4)$$ million events, respectively, collected with the Belle detector. No significant signals are observed in any of the studied production modes, and 90% credibility level (C.L.) upper limits on their branching fractions in $$Upsilon(1S)$$ and $$Upsilon(2S)$$ decays are obtained. The inclusive branching fractions of the $$Upsilon(1S)$$ and $$Upsilon(2S)$$ decays into final states with $$f_1(1285)$$ are measured to be $${cal B}(Upsilon(1S)to f_1(1285)+anything)=(46pm28({rm stat.})pm13({rm syst.}))times 10^{-4}$$ and $${cal B}(Upsilon(2S)to f_1(1285)+anything)=(22pm15({rm stat.})pm6.3({rm syst.}))times 10^{-4}$$. The measured $$chi_{b2} to J/psi + anything$$ branching fraction is measured to be $$(1.50pm0.34({rm stat.})pm0.22({rm syst.}))times 10^{-3}$$, and 90% C.L. upper limits for the $$chi_{b0,b1} to J/psi + anything$$ branching fractions are found to be $$2.3times 10^{-3}$$ and $$1.1times 10^{-3}$$, respectively. For $${cal B}(chi_{b1} to omega + anything)$$, the branching fraction is measured to be $$(4.9pm1.3({rm stat.})pm0.6({rm syst.}))times 10^{-2}$$. All results reported here are the first measurements for these modes.

論文

Study of $$eta$$ and dipion transitions in $$Upsilon(4S)$$ decays to lower bottomonia

Guido, E.*; 谷田 聖; Belle Collaboration*; 他180名*

Physical Review D, 96(5), p.052005_1 - 052005_11, 2017/09

 被引用回数:3 パーセンタイル:55.92(Astronomy & Astrophysics)

We study hadronic transitions between bottomonium states using 496 fb$$^{-1}$$ data collected at the $$Upsilon(4S)$$ resonance with the Belle detector at the KEKB asymmetric energy $$e^+e^-$$ collider. We measure $$B(Upsilon(4S) to pi^+ pi^-Upsilon(1S)) = (8.2 pm 0.5 ({rm stat}) pm 0.4({rm syst})) times 10^{-5}$$, $$B(Upsilon(4S) to pi^+ pi^-Upsilon(2S)) = (7.9 pm 1.0 ({rm stat}) pm 0.4({rm syst})) times 10^{-5}$$, and $$B(Upsilon(4S) to eta Upsilon(1S)) = (1.70 pm 0.23 ({rm stat}) pm 0.08({rm syst})) times 10^{-4}$$. We measure the ratio of branching fractions $$R=B(Upsilon(4S) to eta Upsilon(1S))/B(Upsilon(4S) to pi^+ pi^-Upsilon(1S))=2.07 pm 0.30 ({rm stat}) pm 0.11({rm syst})$$. We search for the decay $$Upsilon(1^3D_{1,2}) to eta Upsilon(1S)$$, but do not find significant evidence for such a transition. We also measure the initial-state radiation production cross sections of the $$Upsilon(2S, 3S)$$ resonances and we find values compatible with the expected ones. Finally, the analysis of the $$Upsilon(4S) to pi^+ pi^-Upsilon(1S)$$ events shows indications for a resonant contribution due to the $$f_0(980)$$ meson.

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