検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年
検索結果: 6 件中 1件目~6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

Differential cross sections and photon beam asymmetries of $$eta$$ photoproduction on the proton at $$E_gamma$$ = 1.3-2.4 GeV

橋本 敏和*; 土川 雄介; LEPS BGOegg Collaboration*; 他58名*

Physical Review C, 106(3), p.035201_1 - 035201_15, 2022/09

 被引用回数:2 パーセンタイル:68.81(Physics, Nuclear)

We report exclusive measurements for the $$eta$$ photoproduction on a proton target. The differential cross sections and photon beam asymmetries of the $$gamma p to eta p$$ reaction are measured in a center-of-mass energy ($$W$$) range of 1.82-2.32 GeV and a polar angle range of $$-1.0 < cos theta_{c.m.}^eta < 0.6$$ by using a large acceptance calorimeter (BGOegg) and forward-angle charged-particle detectors at the SPring-8 LEPS2 beamline. The reaction is identified with a kinematic fitting method to select a recoil proton and two photons produced in an $$eta$$ meson decay. A bump structure at W = 2.0-2.3 GeV in the differential cross section is confirmed at extremely backward $$eta$$ polar angles, where the existing data are inconsistent with each other. This bump structure is likely associated with high-spin resonances that couple with $$sbar{s}$$ quarks. The photon beam asymmetries in a wide $$eta$$ polar angle range for the photon beam energies above 2.1 GeV are reported for the first time, providing an additional constraint to nucleon resonance studies at high energies.

論文

Measurement of the differential cross sections of the $$Sigma^- p$$ elastic scattering in momentum range 470 to 850 MeV/$$c$$

三輪 浩司*; 藤田 真奈美; 長谷川 勝一; 細見 健二; 市川 裕大; 今井 憲一*; 七村 拓野; 成木 恵; 佐甲 博之; 佐藤 進; et al.

Physical Review C, 104(4), p.045204_1 - 045204_20, 2021/10

 被引用回数:9 パーセンタイル:88.26(Physics, Nuclear)

A high statistics $$Sigma p$$ scattering experiment is performed at the J-PARC Hadron Experimental Facility. Momentum-tagged $$Sigma^-$$s running in a liquid hydrogen target are accumulated by detecting the reaction with a high intensity $$pi^-$$ beam of 20 M/spill. The differential cross sections of the $$Sigma^- p$$ elastic scattering were derived with a drastically improved accuracy by identifying approximately 4,500 events from 1.72 $$times$$ 10$$^7$$ $$Sigma^-$$. The derived differential cross section shows a clear forward-peaking angular distribution for a $$Sigma^-$$ momentum range from 470 to 850 MeV/$$c$$. The accurate data will impose a strong constraint on the theoretical models of the baryon-baryon interactions.

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

 被引用回数:6 パーセンタイル:77.42(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 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

 被引用回数:40 パーセンタイル:94.59(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 the branching fraction and time-dependent $$CP$$ asymmetry for $$B^0to J/psipi^0$$ decays

Pal, B.*; 谷田 聖; Belle Collaboration*; 他158名*

Physical Review D, 98(11), p.112008_1 - 112008_8, 2018/12

AA2018-0764.pdf:0.49MB

 被引用回数:3 パーセンタイル:24.14(Astronomy & Astrophysics)

We measure the branching fraction and time-dependent $$CP$$-violating asymmetry for $$B^0to J/psipi^0$$ decays using a data sample of 711 $${rm fb^{-1}}$$ collected on the $$Upsilon(4S)$$ resonance by the Belle experiment running at the KEKB $$e^+e^-$$ collider. The branching fraction is measured to be $$mathcal{B}(B^0to J/psipi^0) = [1.62,pm 0.11~({rm stat}) pm0.07~({rm syst})]times 10^{-5}$$, which is the most precise measurement to date. The measured $$CP$$ asymmetry parameters are $$mathcal{S} = -0.59,pm 0.19~({rm stat}) pm 0.03~({rm syst})$$ and $$mathcal{A} = -0.15,pm 0.14~({rm stat}),^{+0.04}_{-0.03}~({rm syst})$$. The mixing-induced $$CP$$ asymmetry ($$mathcal{S}$$) differs from the case of no $$CP$$ violation by 3.0 standard deviations, and the direct $$CP$$ asymmetry ($$mathcal{A}$$) is consistent with zero.

論文

The Accomplishment of the engineering design activities of IFMIF/EVEDA; The European-Japanese project towards a Li(d,xn) fusion relevant neutron source

Knaster, J.*; Ibarra, A.*; 井田 瑞穂*; 近藤 恵太郎; 菊地 孝行; 大平 茂; 杉本 昌義; 若井 栄一; 渡邊 和仁; 他58名*

Nuclear Fusion, 55(8), p.086003_1 - 086003_30, 2015/08

 被引用回数:58 パーセンタイル:95.37(Physics, Fluids & Plasmas)

国際核融合材料照射施設(IFMIF)は、現在、日欧間の幅広いアプローチ協定の基で工学実証・工学設計活動(EVEDA)フェーズにおける研究開発か進行中である。工学設計活動(EDA)は2013年夏、予定通りに終了し、IFMIF中間工学設計書(The IFMIF Intermediate Engineering Design Report: IIEDR)を刊行した。先行フェーズに比べ、多くの点で設計の改善が行われた。特に、超伝導加速器の概念により、ビームロスの低減と運転コストの低減が実現された。照射施設の設計においては、照射モジュールと放射線遮蔽構造体を分離することによって、照射試験の柔軟性、遠隔操作機器の信頼性の向上とコストの削減が実現された。刊行されたIFMIF中間工学設計書は、EVEDA事業が開始された2007年より実施されている工学実証活動(EVA)の成果を補完し、建設判断を行うに足る情報を提供する。またさらに、益々増す核融合分野からの要求に合致した次の目標を定める上での基礎となる。

6 件中 1件目~6件目を表示
  • 1