2018 Fiscal Year Final Research Report

Photon Physics Revealing Hidden Properties of Quark Matter in the ALICE Experiment

Research Project

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Project/Area Number	26220707
Research Category	Grant-in-Aid for Scientific Research (S)
Allocation Type	Single-year Grants
Research Field	Particle/Nuclear/Cosmic ray/Astro physics
Research Institution	Hiroshima University
Principal Investigator	Sugitate Toru 広島大学, 理学研究科, 教授 (80144806)
Co-Investigator(Kenkyū-buntansha)	濱垣秀樹長崎総合科学大学, 新技術創成研究所, 特命教授 (90114610) 中條達也筑波大学, 数理物質系, 講師 (70418622) 三好隆博広島大学, 理学研究科, 助教 (60335700) 野中千穂名古屋大学, 基礎理論研究センター, 准教授 (10432238)
Research Collaborator	Kunihiro Teiji Miake Yasuo Shigaki Kenta Gunji Taku
Project Period (FY)	2014-05-30 – 2019-03-31
Keywords	クォーク物質 / フォトン物理 / ALICE実験 / クォークグルーオンプラズマ / QGP
Outline of Final Research Achievements	We have carried out our photon and jet physics with the photon spectrometer, PHOS, and the di-jet calorimeter, DCAL, in the ALICE experiment at CERN-LHC, to reveal nature of hot and dense quark matter created in heavy-ion collisions at the highest energy of RUN-2. We have investigated that the matter has been heated up to 3.4 trillion degree Celsius, which is far beyond the Hagedorn limit of hadronic matter, in Pb+Pb central collisions at sqrt(sNN) = 2.8 TeV/A. We have also studied the di-jet production and elliptic flow features, comparing with pp and p+Pb data and with hydro-dynamical model predictions. The models explain the features in general, however, we are looking at quite interesting new phenomena, which could be originated from its initial stage of collisions. Our challenge probing the initial stage with photons is underway.
Free Research Field	実験クォーク物理学
Academic Significance and Societal Importance of the Research Achievements	高温クォーク多体系の探求は非摂動的量子色力学（QCD）の振る舞いを理解するに留まらず、極低温に冷却した原子/分子のボーズ凝縮状態、超伝導/超流動量子臨界相転移現象、あるいは極低温原子の光学格子生成や量子もつれといった最先端科学との関連性を映しだす。自発的に対称性の破れた量子場という自然科学の核心的概念がこれらを結び付ける。この深遠な相互関係の理解を目指し、理論研究者と最新解析結果について相互理解を深めながら普遍的な拡がりをもった新たな学術領域「強く相互作用する量子多体系」の開拓に挑戦する。