Study of quark-gluon structure of hadrons with a large polarized target

2009 Fiscal Year Final Research Report

• Project/Area Number: 18002006
• Research Category: Grant-in-Aid for Specially Promoted Research
• Allocation Type: Single-year Grants
• Review Section: Science and Engineering; Mathematics and Physics
• Research Institution: Yamagata University
• Principal Investigator: IWATA Takahiro Yamagata University, 理学部, 教授 (70211761)
• Co-Investigator(Kenkyū-buntansha): YOSHIDA Hiroshi 山形大学, 基盤教育院, 准教授 (80241727) ; MATSUDA Tatsuro 宮崎大学, 工学部, 教授 (20253817) ; HORIKAWA Naoaki 中部大学, 工学部, 教授 (70022697) ; SUZUKI Hajime 中部大学, 工学部, 准教授 (20260044)
• Co-Investigator(Renkei-kenkyūsha): DOSHITA Norihiro 山形大学, 理学部, 助教 (90451658) ; KONDO Kaori 山形大学, 理学部, 助教 (80451657) ; ISHIMOTO Shigeru KEK, 素粒子原子核研究所, 講師 (50141974) ; HASEGAWA Takeo 宮崎大学, 工学部, 名誉教授 (70025386)
• Project Period (FY): 2006 – 2009
• Keywords: 核子 / スピン / クォーク / グルーオン / ハドロン / QCD

Research Abstract

We have measured the gluon polarization in two reaction channels in order to investigate the origin of the nucleon spin. We obtained the polarization with the best precision ever in both channels. Contribution of the gluon spin to the nucleon spin is found to be not as large as the expectations by theories. We have obtained Collins and Sivers asymmetries which are related to the transverse spin state of quarks and their orbital motion. The results provided with rich information on details of quarks inside the nucleon.

Research Products

• [Journal Article] Gluon Polarisation in the Nucleon and Longitudinal Spin Asymmetries from Open Charm Muoproduction (2009)
  • Author(s): M. Alekseev, N. Doshita, T. Hasegawa, N. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, T. Michigami, other COMPASS Collaboration members.
  • Journal Title: Phys. Lett. B 676 Pages: 31-38
  • Peer Reviewed
• [Journal Article] Measurement of the Longitudinal Spin Transfer to Lambda and Anti-Lambda Hyperons in Polarised Muon DIS. (2009)
  • Author(s): M. Alekseev, N. Doshita, T. Hasegawa, N. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, T. Michigami, other COMPASS Collaboration members.
  • Journal Title: Eur. Phys. J. C 64 Pages: 171-179
  • Peer Reviewed
• [Journal Article] Flavour Separation of Helicity Distributions from Deep Inelastic Muon-Deuteron Scattering (2009)
  • Author(s): M. Alekseev, N. Doshita, T. Hasegawa, N. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, T. Michigami, COMPASS Collaboration members
  • Journal Title: Phys. Lett. B 680 Pages: 217-224
  • Peer Reviewed
• [Journal Article] Collins and Sivers asymmetries for pions and kaons in muon-deuteron DIS (2009)
  • Author(s): M. Alekseev, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, other COMPASS Collaboration members
  • Journal Title: Phys. Lett. B 673 Pages: 127-135
  • Peer Reviewed
• [Journal Article] The Polarised Valence Quark Distribution from semi-inclusive DIS. (2008)
  • Author(s): M. Alekseev, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, other COMPASS Collaboration members
  • Journal Title: Phys. Lett. B 660 Pages: 458-465
  • Peer Reviewed
• [Journal Article] Double spin asymmetry in exclusiveρ0 muoproduction at COMPASS (2007)
  • Author(s): M. Alekseev, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, N. Takabayashi, other COMPASS Collaboration members
  • Journal Title: Eur. Phys. J. C Pages: 255-265
  • Peer Reviewed
• [Journal Article] Spin asymmetry A1(d) and the spin-dependent structure function g1(d) of the deuteron at low values of x and Q**2 (2007)
  • Author(s): V. Yu. Alexakhin, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, N. Takabayashi, other COMPASS Collaboration members
  • Journal Title: Phys. Lett. B 647 Pages: 330-340
  • Peer Reviewed
• [Journal Article] The COMPASS experiment at CERN (2007)
  • Author(s): P. Abbon, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, N. Takabayashi, T. Toeda, other COMPASS Collaboration members
  • Journal Title: Nucl. Instrum. Meth. A 577 Pages: 455-518
  • Peer Reviewed
• [Journal Article] A New measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target. (2007)
  • Author(s): E.S. Ageev, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, T. Toeda, other COMPASS Collaboration members
  • Journal Title: Nucl. Phys. B 765 Pages: 31-70
  • Peer Reviewed
• [Journal Article] The Deuteron Spin-dependent Structure Function g1(d) and its First Moment. (2007)
  • Author(s): V. Yu. Alexakhin, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, T. Iwata, K. Kondo, T. Matsuda, other COMPASS Collaboration members
  • Journal Title: Phys. Lett. B 647 Pages: 8-17
  • Peer Reviewed
• [Journal Article] Gluon polarization in the nucleon from quasi-real photoproduction of high-p(T) hadron pairs. (2006)
  • Author(s): E.S. Ageev, N. Doshita, T. Hasegawa, N. Horikawa, S. Horikawa, S. Ishimoto, T. Iwata, K. Kondo, T. Matsuda, N. Takabayashi, T. Toeda, other COMPASS Collaboration members.
  • Journal Title: Phys. Lett. B 633 Pages: 25-32
  • Peer Reviewed
• [Presentation] Hadron spectroscopy at COMPASS - exotic states at COMPASS (2010)
  • Author(s): Takahiro Iwata
  • Organizer: New Frontiers in QCD - Kyoto, Japan
  • Place of Presentation: (invited)
  • Year and Date: 20100118-20100319
• [Presentation] Future Drell-Yan program of the COMPASS collaboration (2010)
  • Author(s): Norihiro Doshita
  • Organizer: KEK理論センター研究会「High-energy hadron physics with hadron beams」
  • Place of Presentation: ke k, つくば市
  • Year and Date: 20100106-20100108
• [Presentation] Measurements of the Gluon Polarization in the Nucleon at COMPASS (2009)
  • Author(s): Takahiro Iwata
  • Organizer: The 3rd Joint Meeting of the Nuclear Physics Division of the APS and JPS
  • Place of Presentation: Hilton Waikoloa Village, Hawaii
  • Year and Date: 20091013-20091017
• [Presentation] Quark helicity distributions from DIS and SIDIS at COMPASS (2009)
  • Author(s): Tatsuro Matsuda
  • Organizer: he 3rd Joint Meeting of the Nuclear Physics Division of the APS and JPS
  • Place of Presentation: Hilton Waikoloa Village, Hawaii
  • Year and Date: 20091013-20091017
• [Presentation] Tranaverstiy results and polarized Drell-Yan measurement at COMPASS (2009)
  • Author(s): Norihiro Doshita
  • Organizer: The 3rd Joint Meeting of the Nuclear Physics Division of the APS and JPS
  • Place of Presentation: Hilton Waikoloa Village, Hawaii
  • Year and Date: 20091013-20091017
• [Presentation] Polarized Drell-Yan measurement at COMPASS (2009)
  • Author(s): Norihiro Doshita
  • Organizer: 第7回環太平洋高エネルギースピン物理学国際会議
  • Place of Presentation: 遊学館、山形市
  • Year and Date: 20090915-20090918
• [Presentation] Past and future of the COMPASS polarized target (2008)
  • Author(s): Norihiro Doshita
  • Organizer: Symmetries and Spin ( Spin-Praha-2008 )
  • Place of Presentation: Charles University, Prague
  • Year and Date: 20080720-20080726
• [Presentation] Polarized Target for COMPASS Drell-Yan program (2008)
  • Author(s): Norihiro Doshita
  • Organizer: 国際シンポジュム「偏極標的とその応用」
  • Place of Presentation: 月岡ホテル, 上山市
  • Year and Date: 20080229-20080301
• [Presentation] COMPASS Drell-Yan Program (2008)
  • Author(s): Takahiro Iwata
  • Organizer: 59th RIBF Nuclear Physics Seminar
  • Place of Presentation: 理化学研究所、和光市
  • Year and Date: 2008-04-08
• [Presentation] COMPASS Target (2007)
  • Author(s): Norihiro Doshita
  • Organizer: International Workshop on Polarized Sources, Target & Polarimetry
  • Place of Presentation: Brookhaven National Laboratory, New York
  • Year and Date: 20070910-20070914
• [Presentation] Results for Transverse Spin Physics at COMPASS (2007)
  • Author(s): Takahiro Iwata
  • Organizer: The 6th Circum-Pan-Pacific Symposium on High Energy Spin Physics
  • Place of Presentation: University of British Columbia, Canada
  • Year and Date: 20070730-20070802
• [Presentation] Measurement of the Gluon Polarization at COMPASS (2007)
  • Author(s): Norihiro Doshita
  • Organizer: The 6th Circum-Pan-Pacific Symposium on High Energy Spin Physics
  • Place of Presentation: University of British Columbia, Canada
  • Year and Date: 20070730-20070802
• [Presentation] Upgrade of the polarized target and the spectrometer of COMPASS (2006)
  • Author(s): Takahiro Iwata
  • Organizer: Joint Meeting of The PAC Region Particle Physics Communities
  • Place of Presentation: Sheraton Waikiki Hotel, Hawaii
  • Year and Date: 20061030-20061103
• [Presentation] Measurement of Delta_G/G to study gluon spin contribution (2006)
  • Author(s): Kaori Kondo
  • Organizer: Joint Meeting of The PAC Region Particle Physics Communities
  • Place of Presentation: Sheraton Waikiki Hotel, Hawaii
  • Year and Date: 20061030-20061103
• [Presentation] Heat input into the target material (2006)
  • Author(s): Norihiro Doshita
  • Organizer: 3rd Meeting Polarized Nucleon Targets for Europe, in the 6th European Framework Program
  • Place of Presentation: Rech, Germany
  • Year and Date: 20060202-20060204