検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年
検索結果: 4 件中 1件目~4件目を表示
  • 1

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

Observation of a Be double-Lambda hypernucleus in the J-PARC E07 experiment

江川 弘行; 足利 沙希子; 長谷川 勝一; 橋本 直; 早川 修平; 細見 健二; 市川 裕大; 今井 憲一; 金原 慎二*; 七村 拓野; et al.

Progress of Theoretical and Experimental Physics (Internet), 2019(2), p.021D02_1 - 021D02_11, 2019/02

 被引用回数:1 パーセンタイル:100(Physics, Multidisciplinary)

A double-$$Lambda$$ hypernucleus, $${}_{LambdaLambda}mathrm{Be}$$, was observed by the J-PARC E07 collaborationin nuclear emulsions tagged by the $$(K^{-},K^{+})$$ reaction. This event was interpreted as a production and decay of $$ {}_{LambdaLambda}^{;10}mathrm{Be}$$,$${}_{LambdaLambda}^{;11}mathrm{Be}$$, or $${}_{LambdaLambda}^{;12}mathrm{Be}^{*}$$ via $$Xi^{-}$$ capture in $${}^{16}mathrm{O}$$.By assuming the capture in the atomic 3D state, the binding energy of two $$Lambda$$ hyperons$$,$$($$B_{LambdaLambda}$$)of these double-$$Lambda$$ hypernuclei are obtained to be$$15.05 pm 0.11,mathrm{MeV}$$, $$19.07 pm 0.11,mathrm{MeV}$$, and $$13.68 pm 0.11,mathrm{MeV}$$, respectively. Based on the kinematic fitting, $${}_{LambdaLambda}^{;11}mathrm{Be}$$ is the most likely explanation for the observed event.

論文

Search for the rare decay of $$B^+ to ell^{,+} nu_{ell} gamma$$ with improved hadronic tagging

Gelb, M.*; 谷田 聖; Belle Collaboration*; 他185名*

Physical Review D, 98(11), p.112016_1 - 112016_13, 2018/12

 被引用回数:7 パーセンタイル:42.4(Astronomy & Astrophysics)

We present the result of the search for the rare $$B$$ meson decay of $$B^+ to ell^{,+} nu_{ell} gamma$$ with $$ell =e,mu$$. For the search the full data set recorded by the Belle experiment of $$711 , mathrm{fb}^{-1}$$ integrated luminosity near the $$Upsilon (4S)$$ resonance is used. Signal candidates are reconstructed for photon energies $$E_{gamma}$$ larger than $$1 , mathrm{GeV}$$ using a novel multivariate tagging algorithm. The novel algorithm fully reconstructs the second $$B$$ meson produced in the collision using hadronic modes and was specifically trained to recognize the signal signature in combination with hadronic tag-side $$B$$ meson decays. This approach greatly enhances the performance. Background processes that can mimic this signature, mainly charmless semileptonic decays and continuum processes, are suppressed using multivariate methods. The number of signal candidates is determined by analyzing the missing mass squared distribution as inferred from the signal side particles and the kinematic properties of the tag-side $$B$$ meson. No significant excess over the background-only hypothesis is observed and upper limits on the partial branching fraction $$ Delta mathcal{B} $$ with $$E_{gamma} > 1 , mathrm{GeV}$$ individually for electron and muon final states as well as for the average branching fraction of both lepton final states are reported. We find a Bayesian upper limit of $$Delta mathcal{B}( B^{+} to ell^{, +} nu_{ell} gamma) < 3.0 times 10^{-6}$$ at 90% CL and also report an upper limit on the first inverse moment of the light-cone distribution amplitude of the $$B$$ meson of $$lambda_B$$ at 90% CL.

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

 被引用回数:0 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 the higher-order anisotropic flow coefficients for identified hadrons in Au + Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; 今井 憲一; 永宮 正治; 谷田 聖; PHENIX Collaboration*; 他385名*

Physical Review C, 93(5), p.051902_1 - 051902_8, 2016/05

AA2016-0390.pdf:0.48MB

 被引用回数:23 パーセンタイル:9.11(Physics, Nuclear)

Measurements of the anisotropic flow coefficients $$v_2{Psi_2 }$$, $$v_3{Psi_3 }$$, $$v_4{Psi_4 }$$, and $$v_4{Psi_2 }$$, for identified particles ($$pi^{pm}$$, $$K^{pm}$$, and $$p+bar{p}$$) at midrapidity, obtained relative to the event planes $$Psi_m$$ at forward rapidities in Au + Au collisions at $$sqrt{s_{NN}} =$$ 200 GeV, are presented as a function of collision centrality and particle transverse momenta $$p_T$$. The $$vn$$ coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic $$n$$, a modified valence quark-number $$N_q$$ scaling [plotting $$v_n{Psi_m}/(N_q)^{n/2}$$ versus transverse kinetic energies $$(KE_{T})/N_q$$] is observed to yield a single curve for all the measured particle species for a broad range of $$KE_{T}$$. A simultaneous blast-wave model fit to the observed $$v_n{Psi_m}/(p_T)$$ coefficients and published particle spectra identifies radial flow anisotropies $$rho_n{Psi_m}$$ and spatial eccentricities $$s_n{Psi_m}$$ at freeze-out. These are generally smaller than the initial-state participant-plane geometric eccentricities $$epsilon_n{Psi_m^{PP}}$$ as also observed in the final eccentricity from quantum interferometry measurements with respect to the event plane.

4 件中 1件目~4件目を表示
  • 1