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2015 Fiscal Year Research-status Report

原子核偏芯衝突を用いた宇宙最高強度磁場の実験的検出と非線形量子電磁力学への挑戦

Research Project

Project/Area Number 26610071
Research InstitutionHiroshima University

Principal Investigator

志垣 賢太  広島大学, 理学(系)研究科(研究院), 准教授 (70354743)

Project Period (FY) 2014-04-01 – 2017-03-31
Keywords高強度磁場 / 高エネルギー原子核衝突 / 仮想光子 / 偏光
Outline of Annual Research Achievements

強い相互作用における CP 非保存の議論も含めて注目される、高エネルギー原子核の偏芯衝突における宇宙最高強度磁場の生成に対して、直接生成仮想光子に着目した複数の測定量を提案し、世界初の直接的検出に挑む。現在までに、量子電磁力学計算および高エネルギー原子核衝突の流体・粒子描像複合模型計算の助けを得て、現存衝突型加速器において、直接生成仮想光子の非等方生成、偏極、崩壊電子・陽電子対非対称性の3測定量が検出可能な領域との、定量的見積を確立した。熱的光子探索において実光子以上に有効な手段と示した仮想光子測定に特化する新着想により、高エネルギー原子核衝突反応における高強度磁場生成を初めて検証し、電子の臨界磁場を超えた量子電磁力学の非線形領域に初めて実験的に踏込み新規な研究舞台を創始する。
(1)ALICE 実験における最高エネルギー衝突データ収集:LHC 加速器の設計衝突エネルギーほぼ到達に伴い、ALICE 実験において前人未到の核子対あたり 5 TeV の鉛原子核相互衝突反応事象を収集した。衝突エネルギー増加に伴い生成磁場強度もさらなる増加が期待され、より顕著な効果の検出測定と、磁場の強度および時空発展のより高精度での決定を可能とする。
(2)直接生成仮想光子の非等方性および偏極の抽出:RHIC 加速器 PHENIX 実験における原子核衝突反応事象を用いて、低不変質量領域(100 - 300 MeV/c2)の電子・陽電子対生成を測定した。生成粒子の集団運動解析に用いる反応平面を基準として、生成磁場方向に関する仮想光子生成の非等方性と偏極の検出を試みた。特に、ハドロン崩壊光子を中心とする背景雑音光子の寄与の差引による、量子色力学過程に起因する直接生成光子の非等方性と偏極の抽出に向けて、背景雑音寄与差引に最適な偏極観測座標系を決定した。

Current Status of Research Progress
Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

ALICE 実験において前人未到の核子対あたり 5 TeV の鉛原子核相互衝突反応事象を収集した。衝突エネルギー増加に伴い生成磁場強度もさらなる増加が期待される。
生成粒子の集団運動解析に用いる反応平面を基準として、生成磁場方向に関する仮想光子生成の非等方性と偏極の検出を試みた。特に、ハドロン崩壊光子を中心とする背景雑音光子の寄与の差引による、量子色力学過程に起因する直接生成光子の非等方性と偏極の抽出に向けて、背景雑音寄与差引に最適な偏極観測座標系を決定した。

Strategy for Future Research Activity

RHIC 加速器における 100 GeV 領域の金原子核相互衝突反応および LHC 加速器における TeV 領域の鉛原子核相互衝突反応において、電子・陽電子対検出による仮想光子測定を新たな次元に敷延展開し、電子と陽電子の角度分布非対称性から仮想光子の非等方性、偏極、崩壊電子・陽電子対非対称性の 3 つを測定する。この際、量子電磁力学と高エネルギー原子核衝突反応の流体・粒子描像複合模型を駆使して、期待される信号強度と差し引くべき背景雑音成分を定量的に評価して、ハドロン崩壊光子に代表される背景雑音の差引により、直接生成光子成分を抽出する。量子色力学過程に起源を持つ仮想光子の、衝突系の巨視的回転方向に対する非等方性に関する複数の測定により、宇宙最高強度の磁場生成と時空発展を直接的に検出する。電子の臨界磁場を上回る高強度磁場生成を実験的に確立し、非線形量子電磁力学の研究舞台を開拓する。

Causes of Carryover

平成 26 年度には当初、流体・粒子描像複合模型計算による磁場の時空発展の理解に向けた研究会主催を計画したが、直接生成仮想光子の非等方性および偏光の抽出と衝突反応軸に対する直接仮想光子崩壊電子・陽電子の荷電非対称性の検出に向けた、実データ解析手法の確立を優先した。平成 27 年度も引続き、特にハドロン崩壊光子を中心とする背景雑音光子の寄与差引に向けた偏極観測座標系の決定など、解析手法の確実な理解と確立を優先し、上述の研究会については平成 28 年度に計画する非線形量子電磁力学への挑戦に掛かる研究会との併合を検討して、開催を見送ったため、次年度使用額が生じた。

Expenditure Plan for Carryover Budget

LHC 加速器 ALICE 実験と RHIC 加速器 PHENIX 実験の双方において、直接生成仮想光子の非等方性および偏光の抽出を目指し、実データ解析を一層推進し、並行して、連携研究者との協力をさらに強化し、高強度磁場生成に関わる物理理解と高強度場の下で発現する非線形量子電磁力学に関わる物理議論を深化させるため、次年度使用額は平成 28 年度助成金と併せ、旅費等に使用する。

  • Research Products

    (44 results)

All 2015 Other

All Int'l Joint Research (3 results) Journal Article (36 results) (of which Int'l Joint Research: 36 results,  Peer Reviewed: 36 results,  Open Access: 25 results,  Acknowledgement Compliant: 36 results) Presentation (4 results) (of which Int'l Joint Research: 3 results,  Invited: 4 results) Remarks (1 results)

  • [Int'l Joint Research] ブルックヘブン国立研究所/ニューヨーク州立大学/カリフォルニア大学(米国)

    • Country Name
      U.S.A.
    • Counterpart Institution
      ブルックヘブン国立研究所/ニューヨーク州立大学/カリフォルニア大学
    • # of Other Institutions
      38
  • [Int'l Joint Research] CERN(スイス)

    • Country Name
      SWITZERLAND
    • Counterpart Institution
      CERN
  • [Int'l Joint Research]

    • # of Other Countries
      39
  • [Journal Article] Coherent ψ(2S) photo-production in ultra-peripheral Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Lett.

      Volume: B751 Pages: 358-370

    • DOI

      10.1016/j.physletb.2015.10.040

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Precision measurement of the mass difference between light nuclei and anti-nuclei2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Nature Phys.

      Volume: 11 Pages: 811-814

    • DOI

      10.1038/nphys3432

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurements of elliptic and triangular flow in high-multiplicity 3He+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. Lett.

      Volume: 115 Pages: 142301

    • DOI

      10.1103/PhysRevLett.115.142301

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Centrality dependence of inclusive J/ψ production in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1511 Pages: 127

    • DOI

      10.1007/JHEP11(2015)127

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] φ meson production in d+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 92 Pages: 044909

    • DOI

      10.1103/PhysRevC.92.044909

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] One-dimensional pion, kaon, and proton femtoscopy in Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 92 Pages: 054908

    • DOI

      10.1103/PhysRevC.92.054908

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Centrality dependence of high-pT D meson suppression in Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1511 Pages: 205

    • DOI

      10.1007/JHEP11(2015)205

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of jet quenching with semi-inclusive hadron-jet distributions in central Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1509 Pages: 170

    • DOI

      10.1007/JHEP09(2015)170

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at √s = 7 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1509 Pages: 148

    • DOI

      10.1007/JHEP09(2015)148

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Inclusive, prompt and non-prompt J/ψ production at mid-rapidity in Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1507 Pages: 051

    • DOI

      10.1007/JHEP07(2015)051

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Systematic study of charged-pion and kaon femtoscopy in Au+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 92 Pages: 034914

    • DOI

      10.1103/PhysRevC.92.034914

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of pion, kaon and proton production in proton-proton collisions at √s = 7 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Eur. Phys. J.

      Volume: C75 Pages: 226

    • DOI

      10.1140/epjc/s10052-015-3422-9

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Coherent ρ0 photo-production in ultra-peripheral Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1509 Pages: 095

    • DOI

      10.1007/JHEP09(2015)095

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Rapidity and transverse-momentum dependence of the inclusive J/ψ nuclear modification factor in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1506 Pages: 055

    • DOI

      10.1007/JHEP06(2015)055

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of dijet kT in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Lett.

      Volume: B746 Pages: 385-395

    • DOI

      10.1016/j.physletb.2015.05.033

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of charged jet production cross sections and nuclear modification in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Lett.

      Volume: B749 Pages: 68-81

    • DOI

      10.1016/j.physletb.2015.07.054

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of jet suppression in central Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Lett.

      Volume: B746 Pages: 1-14

    • DOI

      10.1016/j.physletb.2015.04.039

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Two-pion femtoscopy in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 034906

    • DOI

      10.1103/PhysRevC.91.034906

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Forward-backward multiplicity correlations in pp collisions at √s = 0.9, 2.76 and 7 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1505 Pages: 097

    • DOI

      10.1007/JHEP05(2015)097

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Centrality dependence of particle production in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      J. Adam, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 064905

    • DOI

      10.1103/PhysRevC.91.064905

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Systematic Study of Azimuthal Anisotropy in Cu+Cu and Au+Au Collisions at √sNN = 62.4 and 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 92 Pages: 034913

    • DOI

      10.1103/PhysRevC.92.034913

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Inclusive photon production at forward rapidities in proton-proton collisions at √s = 0.9, 2.76 and 7 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Eur. Phys. J.

      Volume: C75 Pages: 146

    • DOI

      10.1140/epjc/s10052-015-3356-2

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Charged jet cross sections and properties in proton-proton collisions at √s = 7 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. D

      Volume: 91 Pages: 112012

    • DOI

      10.1103/PhysRevD.91.112012

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Production of inclusive Υ(1S) and Υ(2S) in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Phys. Lett.

      Volume: B740 Pages: 105-117

    • DOI

      10.1016/j.physletb.2014.11.041

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Charged-pion cross sections and double-helicity asymmetries in polarized p+p collisions at √s = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. D

      Volume: 91 Pages: 032001

    • DOI

      10.1103/PhysRevD.91.032001

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Search for dark photons from neutral meson decays in p+p and d+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 031901

    • DOI

      10.1103/PhysRevC.91.031901

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Multiplicity dependence of jet-like two-particle correlation structures in p-Pb collisions at √sNN = 5.02 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Phys. Lett.

      Volume: B741 Pages: 38-50

    • DOI

      10.1016/j.physletb.2014.11.028

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Production of Σ(1385)± and Ξ(1530)0 in proton-proton collisions at √s = 7 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Eur. Phys. J.

      Volume: C75 Pages: 1

    • DOI

      10.1140/epjc/s10052-014-3191-x

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Elliptic flow of identified hadrons in Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      JHEP

      Volume: 1506 Pages: 190

    • DOI

      10.1007/JHEP06(2015)190

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of electrons from semileptonic heavy-flavor hadron decays in pp collisions at √s = 2.76 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. D

      Volume: 91 Pages: 012001

    • DOI

      10.1103/PhysRevD.91.012001

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Cross section for bb-bar production via dielectrons in d+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 014907

    • DOI

      10.1103/PhysRevC.91.014907

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Centrality dependence of low-momentum direct-photon production in Au+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 064904

    • DOI

      10.1103/PhysRevC.91.064904

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Heavy-quark production and elliptic flow in Au+Au collisions at √sNN = 62.4 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 044907

    • DOI

      10.1103/PhysRevC.91.044907

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central d+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. Lett.

      Volume: 114 Pages: 192301

    • DOI

      10.1103/PhysRevLett.114.192301

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] Measurement of Υ(1S+2S+3S) production in p+p and Au+Au collisions at √sNN = 200 GeV2015

    • Author(s)
      A. Adare, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 024913

    • DOI

      10.1103/PhysRevC.91.024913

    • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
  • [Journal Article] K*(892)0 and φ(1020) production in Pb-Pb collisions at √sNN = 2.76 TeV2015

    • Author(s)
      B. Abelev, K. Shigaki, et al.
    • Journal Title

      Phys. Rev. C

      Volume: 91 Pages: 024609

    • DOI

      10.1103/PhysRevC.91.024609

    • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
  • [Presentation] Overview of MFT Activities in/at Japan/Hiroshima2015

    • Author(s)
      K. Shigaki
    • Organizer
      6th ALICE ITS upgrade, MFT and O2 Asian Workshop
    • Place of Presentation
      Seoul, South Korea
    • Year and Date
      2015-12-07 – 2015-12-09
    • Int'l Joint Research / Invited
  • [Presentation] Dilepton Measurement at ALICE - especially the Muon Forward Tracker Upgrade2015

    • Author(s)
      K. Shigaki for the ALICE Collaboration
    • Organizer
      ECT* Workshop, New Perspectives on Photons and Dileptons in Ultrarelativistic Heavy-Ion Collisions at RHIC and LHC
    • Place of Presentation
      Trento, Italy
    • Year and Date
      2015-11-30 – 2015-12-11
    • Int'l Joint Research / Invited
  • [Presentation] Status and Plans in Japan2015

    • Author(s)
      K. Shigaki
    • Organizer
      ALICE MFT Meeting at Hiroshima University
    • Place of Presentation
      Hiroshima, Japan
    • Year and Date
      2015-10-05 – 2015-10-05
    • Int'l Joint Research / Invited
  • [Presentation] 高エネルギー原子核衝突を用いた極限状態の実験的探究2015

    • Author(s)
      志垣賢太
    • Organizer
      東北大学大学院理学研究科セミナー
    • Place of Presentation
      東北大学
    • Year and Date
      2015-07-03 – 2015-07-03
    • Invited
  • [Remarks] LHC ALICE 実験 - ALICE JAPAN -

    • URL

      http://alice-j.org/

URL: 

Published: 2017-01-06  

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