パートン非束縛相の確実な検証と包括的理解:電子対と光子による複数の透過的測定から

• Project/Area Number: 18340067
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Hiroshima University
• Principal Investigator: 志垣 賢太 Hiroshima University, 大学院・理学研究科, 准教授 (70354743)
• Project Period (FY): 2006 – 2008
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥10,480,000 (Direct Cost: ¥8,800,000、Indirect Cost: ¥1,680,000); Fiscal Year 2008: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2007: ¥3,640,000 (Direct Cost: ¥2,800,000、Indirect Cost: ¥840,000); Fiscal Year 2006: ¥3,200,000 (Direct Cost: ¥3,200,000)
• Keywords: パートン多体系 / 原子核衝突実験

Research Abstract

本研究では、米国ブルックヘブン国立研究所の相対論的重イオン衝突型加速器RHICを用いた稀事象精密測定実験PHENIXを推進し、電子陽電子対測定と光子測定の有機的結合によるパートン非束縛相の確実な検証と包括的物理理解を目標とした。平成20年度の主な研究成果を列挙する:
1.PHENIX実験において金原子核+金原子核衝突事象の比較対照データとなる核子間衝突重心エネルギー√<SNN>=200GeV(RHIC加速器最高エネルギー)における重陽子+金原子核衝突反応の高輝度高統計データ収集を平成19年度末から継続して推進し、従前の積分輝度2.7nb^(-1)の約30倍となる80nb^(-1)を収集した。特に不変質量の小さい領域での電子陽電子対測定および低〜中間横運動量領域の光子測定を主導した。
2.RHIC加速器において、前項と並び比較対照データとなる√<S>=200GeVの陽子+陽子衝突の高統計運転を推進した。運転継続中のため到達積分輝度は未詳である。
3.収集した金原子核+金原子核,銅原子核+銅原子核、重陽子+金原子核、陽子+陽子衝突事象からの電子陽電子対測定および光子測定に基づき、パートン非束縛相中における軽いベクトル中間子の収量・横運動量スペクトル・質量状態・各崩壊過程への分岐比などを広い運動学領域で系統的に精査し、定量的知見の向上を得た。
4.高精度高統計の光子測定に基づき、直接生成光子測定の系統誤差低減を中心に、熱平衡パートン非束縛相からの熱輻射光子探索に向けての進展を得た。
5.理論研究者との連携を強化し、今後のRHIC加速器における実験に対する改善の余地を検討し、また欧州合同原子核研究機構で建設中のLHC加速器ALICE実験も視野に、包括的物理理解へ向けた非摂動的量子色力学現象の詳細な議論の礎の構築を推進した。

Research Products

• [Journal Article] inclusive cross section and double helicity asymmetry for piO production in p+p collisions at sqrt(s) = 62.4 GeV (2009)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. D 79
  • Peer Reviewed
• [Journal Article] dilepton mass spectra in p+p collisions at sqrt(s)= 200 GeVand the contribution from open charm (2009)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Lett. B 670 Pages: 313-320
  • Peer Reviewed
• [Journal Article] suppression pattern of neutral pions at high transverse momentum in Au+Au collisions at sqrt(sNN)=200 Gev and constraints on medium transport coefficients (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 101
  • Peer Reviewed
• [Journal Article] onset of piO suppression studied in Cu+Cu collisions at sqrt(sNN)=22.4, 62.4, and 200 GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 101
  • Peer Reviewed
• [Journal Article] J/Psi production in sqrt(sNN)= 200 GeV Cu+Cu collisions (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 101
  • Peer Reviewed
• [Journal Article] particle-species dependent modification of jet-inducedcorrelations in Au+Au collisions at sqrt(sNN)= 200GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 101
  • Peer Reviewed
• [Journal Article] source breakup dynamics in Au+Au Collisions at sqrt(sNN)= 200 GeV via three-dimensional two-pionsource imaging (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 100
  • Peer Reviewed
• [Journal Article] quantitative constraints on the opacity of hot partonic matter from semi-inclusive single high transverse momentum pion suppression in Au+Au collisions at sqrt(sNN)= 200 GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 77
  • Peer Reviewed
• [Journal Article] charged hadron multiplicity fluctuations in Au+Au and Cu+Cu collisions from sqrt(s_NN)= 22.5 to 200 GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 78
  • Peer Reviewed
• [Journal Article] cold nuclear matter effects on J/Psi as constrained bydeuteron-gold measurements at sqrt(sNN)=200 GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 77
  • Peer Reviewed
• [Journal Article] centrality dependence of charged hadron production indeuteron + gold and nucleon + gold collisions atsqrt(sNN)= 200 GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 77
  • Peer Reviewed
• [Journal Article] dihadron azimuthal correlations in Au+Au collisions atsqrt(sNN)= 200 GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 78
  • Peer Reviewed
• [Journal Article] transverse momentum and centrality dependence of dihedroncorrelations in Au+Au collisions at sqrt(sNN)= 200 GeV : iet-quenching and the response of partonic matter (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 77
  • Peer Reviewed
• [Journal Article] centrality dependence of charged hadron production in deuteron+gold and nucleon+gold collisions at s (NN)**(1/2)=200-GeV (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 77
  • Peer Reviewed
• [Journal Article] transverse momentum and centrality dependence of dihadron correlations in Au+Au collisions at s (NN)=200-GeV:Jet-quenching and the response of partonic matter (2008)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 77
  • Peer Reviewed
• [Journal Article] elliptic flow for phi mesons and (anti) deuterons in Au+Au collisions at s (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 99
  • Peer Reviewed
• [Journal Article] system size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at s (NN)**(1/2=200 and 62.4-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] J/psi production vs centrality, transverse momentum, and rapidity in Au+Au Collisions at s (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] J/psi production versus transverse momentum and rapidity in p+p collisions ats**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] centrality dependence of pi0 and eta production at large transverse momentum in s (NN)**(1/2)=200-GeV d+Au collisions (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] energy loss and flow of heavy quarks in Au+Au collisions at s (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] scaling properties of azimuthal anisotropy in Au+Au and Cu+Cu collisions at s (NN)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] evidence for a long-range component in the pion emission source in Au+Au collisions at s (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] measurement of direct photon production in p+p collisions at s**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. Lett. 98
  • Peer Reviewed
• [Journal Article] a detailed study of high-p (T) neutral pion suppression and azimuthal anisotropy in Au+Au Collisions at s (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 76
  • Peer Reviewed
• [Journal Article] measurement of density correlations in pseudorapidity via charged particle multiplicity fluctuations in Au+Au collisions at s(NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 76
  • Peer Reviewed
• [Journal Article] production of omega mesons at large transverse momenta in p+p and d+Au collisions at s**(1/2)(NN)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 75
  • Peer Reviewed
• [Journal Article] high transverse momentum eta meson production in p+p, d+Au and Au+Au collisions at S (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. C 75
  • Peer Reviewed
• [Journal Article] measurement of single muons at forward rapidity in p+p Collisions at s**(1/2)=200-GeV and implications for charm production (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. D 76
  • Peer Reviewed
• [Journal Article] inclusive cross-section and double helicity asymmetry for pi0 production in p+p collisions at s**(1/2)=200-GeV:implications for the polarized gluon distribution in the proton (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Rev. D 76
  • Peer Reviewed
• [Journal Article] correlated production of p and anti-p in Au+Au collisions at s (NN)**(1/2)=200-GeV (2007)
  • Author(s): PHENIX Collaboration
  • Journal Title: Phys. Lett. B 649 Pages: 359-369
  • Peer Reviewed
• [Journal Article] High transverse momentum eta meson production in p+p,d+Au and Au+Au collisions at √<s_<NN>> = 200 GeV (2007)
  • Author(s): PHENIX Collaboration (S. S. Adler et al.)
  • Journal Title: Physical Review c75
• [Journal Article] Measurement f direct photon production in p+p collisions at √<s> = 200 GeV (2007)
  • Author(s): PHENIX Collaboration (S. S. Adler et al.)
  • Journal Title: Physical Review Letters 98
• [Journal Article] Measurement of high pt single electrons from heavy flavor decays in p+p collisions at √<s> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration (A. Adare et al.)
  • Journal Title: Physical Review Letters 97
• [Journal Article] Jet properties from dihadron correlations in p+p collisions at √<s> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration (S. S. Adler et al.)
  • Journal Title: Physical Review D74
• [Journal Article] Azimuthal angle correlations for rapidity separated hadron pairs in d+Au collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration (S. S. Adler et al.)
  • Journal Title: Physical Review Letters 96
• [Journal Article] Nuclear effects on hadron production in d+Au and p+p collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration (S. S. Adler et al.)
  • Journal Title: Physical Review c74
• [Journal Article] Nuclear modification of electron spectra and implications for heavy quark energy loss in Au+Au collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review Letters 96
• [Journal Article] Jet structure from dihadron crrelations in D+Au collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review C73
• [Journal Article] Measurement of identified p0 and inclusive photon V2 and implication to the direct photon production in √<s_<NN>> = 200 GeV Au+Au collisions (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review Letters 96
• [Journal Article] Single electrons from heavy flavor decays in p+p collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review Letters 96
• [Journal Article] J/Ψ production and nuclear effects for d+Au and p+p collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review Letters 96
• [Journal Article] Modification to di-jet hadron pair correlations in Au+Au collisions at √<s_<NN>> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review Letters 97
• [Journal Article] Improved measurement of double helicity asymmetry in inclusive midrapidity π^0 production for polarized p+p collisions at √<s> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review D73
• [Journal Article] Common suppression patter of eta and π^0 mesons at high transverse momentum in Au+Au collisions at √<s> = 200 GeV (2006)
  • Author(s): PHENIX Collaboration(S. S. Adler et al.)
  • Journal Title: Physical Review Letters 96
• [Presentation] quark tomography at very high pT at ALICE (2009)
  • Author(s): 志垣賢太
  • Organizer: 名古屋大学ミニワークショップphotons and leptons in hot/dense QCD
  • Place of Presentation: 名古屋大学
  • Year and Date: 2009-03-03
• [Presentation] exploration of hot partonic matter at LHC-ALICE (2009)
  • Author(s): 志垣賢太
  • Organizer: 京都大学基礎物理学研究所第 16回湯川国際セミナー会議
  • Place of Presentation: 京都大学基礎物理学研究所
  • Year and Date: 2009-02-18
• [Presentation] low-mass vector mesons and continuum at RHIC-PHENIX (2009)
  • Author(s): 志垣賢太
  • Organizer: winter workshop on nuclear dynamics2009
  • Place of Presentation: 米国モンタナ州ビッグスカイ
  • Year and Date: 2009-02-06
• [Presentation] towards LHC-ALICE collaboration (2008)
  • Author(s): 志垣賢太
  • Organizer: asian triangle heavy ion conference2008
  • Place of Presentation: 筑波大学
  • Year and Date: 2008-10-13
• [Presentation] ALICE 実験準備状況 (2008)
  • Author(s): 志垣 賢太
  • Organizer: 日本物理学会シンポジウム
  • Place of Presentation: 近畿大学
  • Year and Date: 2008-03-24
• [Presentation] physics in initial years at ALICE (2007)
  • Author(s): 志垣 賢太
  • Organizer: 大阪大学核物理研究センター研究会
  • Place of Presentation: 大阪大学核物理研究センター
  • Year and Date: 2007-10-30
• [Presentation] physics via penetrating probes at ALICE (2007)
  • Author(s): 志垣 賢太
  • Organizer: 日本物理学会
  • Place of Presentation: 北海道大学
  • Year and Date: 2007-09-24
• [Presentation] low mass vector mesons at high energy densities at RHIC-PHENIX (2007)
  • Author(s): 志垣 賢太
  • Organizer: International Nuclear Physics Conference 2007
  • Place of Presentation: 東京国際フォーラム