2013.5.9 updated
*原則として水曜日, 16号館829会議室にて.
4/17, 24(WED)16:00-渡邉和宏Heavy quark pair production in high-energy pA collisions: quarkonium and open flavors
4/26(Fri)16:00-A. Dumitru (RBRC/Baruch College)Magnetic flux loop in high-energy heavy-ion collisions
We consider the expectation value of a magnetic flux loop in the immediate forward light cone of collisions of heavy nuclei at high energies. Such collisions are characterized by a non-linear scale Q_s where color fields become strong. We find that loops of area greater than ~2/Q_s^2 exhibit area law behavior, which determines the scale of elementary flux excitations ("vortices"). We also estimate the magnetic string tension, sigma_M = 0.12 Q_s^2. By the time t ~ 1/Q_s even small loops satisfy an area law while substantial magnetic fields remain only at large distances. We describe corrections to the propagator of semi-hard gluons at very early times in the background of fluctuating magnetic fields.
5/1(WED)16:00-奈良寧(国際教養大) Initial state model of heavy ion collisions at RHIC/LHC
Hydrodynamics fit many data from RHIC and LHC. However, results of hydrodynamical simulation strongly depend on initial conditions. I will show recent development of models which compute initial gluon production in heavy ion collisions. The model is implemented in a Monte-Carlo method and initial state fluctuations are included.
5/15(WED)16:00- 吉田信介(理研) Application of the twist-3 framework to the high energy spin
5/22(WED)16:00- 本郷優(東大理) カイラル磁気・分離効果を含む相対論的流体モデル
ブルックヘブン国立研究所のRHIC,欧州原子核研究機構のLHCにおいて,クォーク・グルーオン・プラズマ(QGP)という超高温の物質状態の実現を目指した相対論的重イオン衝突実験が行われている.実験結果はその生成を強く示すものであり,生成されたQGPは粘性の影響の小さな相対論的流体として振る舞うことが明らかになった.一方,重イオン衝突実験においては極めて強い電磁場が形成されると考えられておりその研究が盛んに行われているが,中でも磁場に関連してカイラル磁気効果(Chiral Magnetic Effect, CME)やカイラル分離効果(Chiral Separation Effect, CSE)という特異な現象が提案されている.これらは量子異常の大局的な現れとして,磁場に沿ってそれぞれ散逸を伴わない電流や軸性電流が生じるという特異な現象であり,どちらも相対論的流体力学の枠組みに取り込めることが指摘されている.本研究ではこのCMEやCSEを含んだ相対論的流体力学について紹介した後,これらの輸送現象に着目して行った流体シミュレーションの結果を紹介する.また,計算結果からごく最近観測された電荷依存の楕円フローに与える影響について論じる.
6/5(WED)16:00- 益田晃太(東大理) Hadron-Quark Crossover and Massive Hybrid Stars
Neutron star (NS) is a cosmic laboratory which provides us with a testing ground for the rich phase structure of quantum chromodynamics (QCD) through the observables. Among others, mass and radius are particularly important probes for constraining the equation of state (EOS) and the composition of high density matter. From the observational point of view, a massive NS, PSR J1614-2230, with (1.97±0.04) solarmass was recently discovered. In this seminar, we investigate whether the hybrid stars which have quark matter in the core are compatible with 2 solarmass NS. On the basis of the percolation picture from the hadronic phase with hyperons to the quark phase with strangeness, we construct a new EOS. The maximum mass of neutron stars can exceed 2 solarmass if the following two conditions are satisfied; (i) the crossover takes place at around three times the normal nuclear matter density, and (ii) the quark matter is strongly interacting in the crossover region. Although the choice of the hadronic EOS does not affect the above conclusion on the maximum mass, the three-body force among nucleons and hyperons plays an essential role for the onset of the hyperon mixing and the cooling of neutron stars. Moreover we also comment on colorsuperconducting phase inside NSs.
10/9(WED)16:00- 田屋英俊 重イオン衝突実験でのQGP生成機構
10/16(WED)16:00- 藤井宏次 Hybrid Monte Carlo on Lefschetz Thimbles -- A study of the residual sign problem
10/23(WED)16:00- 渡邉和宏 Color singlet model of J/Psi production in high energy pA collision
11/6(WED)16:00- 西田祐介(東工大) New analogies between extreme QCD and cold atoms
I will discuss two possible new analogies between extreme QCD and cold atoms. One is the analogue of "hard probes" in strongly-interacting atomic gases [arXiv:1110.5926]. The other is the analogue of "quark-hadron continuity" in a three-component Fermi gas [arXiv:1207.6971].
11/13(WED)16:00- 橋本省二(KEK) 有限温度QCD相転移におけるU_A(1)対称性の役割 ~ 格子QCD計算による研究
対称性にもとづいた議論により2フレーバーQCDの有限温度相転移は(クォーク 質量ゼロの極限では)2次相転移というのが定説になっているが、仮にU_A(1) 対称性が転移点で同時に回復していたら、この議論は成り立たない。このセミ ナーでは、格子QCD計算の現状と問題点を整理した上で、この問題にかかわる 最近の研究について報告する。

Journal Club
*大抵の金曜日, 3号館108号室にて.
4/19(FRI)16:00- 松井Indiana U, MIT滞在報告
5/10(FRI)15:00- 山崎 Nonet Meson Properties in Nambu-Jona-Lasinio model with dimensional versus cutoff regularization
T. Inagaki, D. Kimura, H. Kohyama, A. Kvinikhidze, Phys. Rev. D83, 034005 (2011).
5/17(FRI)16:00- 藤井 Bose-Einstein Condensation and Thermalization of the Quark Gluon Plasma
J.-P. Blaizot, F. Gelis, J.-f. Liao, L. McLerran, R. Venugopalan, arXiv:1107.5296
5/24(FRI)16:00- 田屋 Syncrotron Radiation in a chromomaginetic field
A. Dbeyssi, D. Al Dirani, H. Zaraket, PRD84, 105033 (2011)
5/31(FRI)16:00- 渡邉 New data from pA collisions and our recent results
group discussions; LHCb-CONF-2012-034, LHCb-CONF-2013-008
6/14(FRI)16:00- 松井 Jet quenching at LHC
brief summary of experimental data, ATLAS:PRL105 (2010) 252303, CMS:PRC84 (2011) 024906; PLB712 (2012) 176.
7/3(Wed)16:00- 藤井 Report on Trent workshop, h3QCD
7/5(Fri)16:00- 山崎 Presentation practice for SQM
10/18(Fri)16:00- 山崎 Quark-hadron matter at finite temperature and density in a two color PNJL model
S. Imai, H. Toki, W. Weise, Nucl. Phys. A913 (2013) 71.