Experimentally yet unobserved hadrons from QCD thermodynamics

Size: px

Start display at page:

Download "Experimentally yet unobserved hadrons from QCD thermodynamics"

Thomas Smith
5 years ago
Views:

1 Experimentally yet unobserved hadrons from QCD thermodynamics Heng-Tong Ding ( 丁亨通 ) Central China Normal University (CCNU) 中国科学技术大学交叉学科理论研究中心合肥, /41

2 Experimentally yet unobserved hadrons from QCD thermodynamics Heng-Tong Ding ( 丁亨通 ) Central China Normal University (CCNU) 中国科学技术大学交叉学科理论研究中心合肥, /41

3 A newly founded lattice QCD ( ) Group members: 1 Professor: Heng-Tong Ding ( 丁亨通 ) 1 Postdoc: Prasad Hegde 1 PhD student Hai-Tao Shu ( 舒海涛 ) & 1 master student Sheng-Tai Li ( 李圣泰 ) Research interests: properties of nuclear matter under extreme conditions QCD phase diagram QCD Equation of state at nonzero baryon density In-medium hadron properties Outcomes: 3 publications in journals + 5 conference proceedings 2 Phys. Rev. Lett. (published by Editors suggestions) + 1 Phys. Lett. B 3 Nucl. Phys. A + 2 Proceedings of Science 2 invited plenary talks (Quark Matter Hard Probes 2013) 3 parallel talks (2 in Lattice in Quark Matter 2014) + 1 seminar@yitp Homepage: 2 /41

4 Experimentally not yet observed hadrons from QCD thermodynamics Heng-Tong Ding ( 丁亨通 ) Central China Normal University (CCNU) Phys. Rev. Lett. 113(2014) , Phys. Lett. B 737 (2014) 210 Phys. Rev. Lett. 13(2014)082001, Phys.Rev. Lett. 111(2013) BNL-Bielefeld-CCNU collaboration A. Bazavov, H.-T. Ding, P. Hegde, O. Kaczmarek, F. Karsch, E. Laermann, Y. Maezawa, S. Mukherjee, H. Ohno, P. Petreczky, C. Schmidt, S. Sharma, W. Söldner, M. Wagner 中国科学技术大学交叉学科理论研究中心合肥, /41

5 Particle Data Book(let) Travel Particle data book 3 /41

6 Particle Data Book(let) Travel Particle data book 3 /41

7 第一个关于实验上尚未探测到的奇异强子存在的间接证据 4 /41

8 编辑建议发表文章额外的奇异强子的热力学贡献和! 对实验中的冻结条件的影响 BNL-Bielefeld-CCNU collaboration comments from the Editor abstract 实验上尚未观测到的粒子特别是那些奇异强子, 让我们理解了格点量子色动力学在 QGP 相变附近的计算结果 5 /41

9 Outline Lattice QCD and QCD transition Evidence for the thermodynamic contribution from experimentally not yet observed hadrons Influence of missing hadron states in the determination of hadronization T in the strange hadron sector 6 /41

10 quarks, gluons & strong force mass of proton ~ 938 MeV mass of u(d) quarks ~ 3 MeV m=e/c 2 99% of the proton mass comes from the strong force 7 /41

11 Quantum ChromoDynamics L = 1 4 Ga µ G µ a + q µ (i@ µ gt a A a µ)q m qq two peculiar features of QCD: asymptotic freedom QCD running coupling s4 confinement David J. Gross 2004 H. David Politzer Frank Wilczek for the discovery of asymptotic freedom in the theory of the strong interaction 8 /41

12 Non-perturbative physics QCD running coupling perturbative methods not able to describe low-energy & long distance physics first principle calculations? 9 /41

13 Lattice gauge theory Kenneth G. Wilson June 8, June 15, 2013 for his theory for critical phenomena in connection with phase transitions /41

transcription of the gauge and fermions degree of freedom construction of the action definition of

14 Formulation of lattice gauge theory Lattice QCD calculation is a non-perturbative implementation of field theory using the Feynman path integral approach discretization of space time the transcription of the gauge and fermions degree of freedom construction of the action definition of the measure of integration in the path integral the transcription of the operators used to probe the physics 11/41

15 Basics of Lattice QCD Four dim. Euclidean lattice a λ an σ Temperature adsf To get continuum physics, make at constant V and T Input parameters lattice gauge coupling: quark masses lattice size: No free parameters input bare parameters of QCD Lagrangian fixed by reproducing physics at T=0 12/41

16 Basics of Lattice QCD (cont.) Expectation value of QCD observables on the lattice Sf: staggered, Wilson, Domain Wall fermions... Operator with each configuration is summed up with weight exp(-slat) Average over configurations with huge degree of freedoms Monte Carlo simulations: generate gauge field configurations with weight exp(-sg+log(detmf)) detmf=constant: quenched approximation detmf constant: dynamical full QCD simulation Ndeg. Nc Nf Nspin Nd N σ N τ 10 6 O: chiral condensates, susceptibilities, correlation functions 3 13/41

17 Top500 List - June 2014 MIC GPU BGQ CPU BGQ GPU MIC BGQ BGQ CPU GPU Architectures for! High Performance Computing: Intel, MIC, Co-processors! Multiple Integrated Cores! Nvidia, GPU gaming cards! Graphic Processing Unit! IBM: Blue Gene/Q! 14/41

18 QCDSP: QCD on a digital Signal Processor Tflops - completed Gordon Bell Prize QCDOC: QCD On a Chip - 10 Tflops - completed Parent of IBM Bluegene 15/41

19 天津超算中心天河二号 GPU 架构 16/41

至强协处理器 (Xeon Phi Co-processor)@ 天河二号一块 Xeon Phi 7120P 卡含 61

268(4x61 + 4x6) 核编写优化了符合 Xeon Phi Coprocessor 架构的适合于做 QCD 相结构

20 至强协处理器 (Xeon Phi 天河二号一块 Xeon Phi 7120P 卡含 61 个协处理器研发调试 : 已购买了 2 台高性能计算机, 共 4 块 Xeon Phi 7120p 卡, 总计 268(4x61 + 4x6) 核编写优化了符合 Xeon Phi Coprocessor 架构的适合于做 QCD 相结构工作的计算程序广州超算中心 ( 中山大学 ) 的天河二号目前世界上最快的超级计算机正在免费试用天河二号上的计算资源 17/41

21 mass of proton calculated from QCD? mass of proton ~ 938 MeV mass of u(d) quarks ~ 3 MeV Only Lattice QCD is able to calculate the mass of proton 18/41

22 first numerical lattice QCD study string tension lattice gauge coupling 19/41

23 QGP: a new state of matter μb ΛQCD or T ΛQCD Quark Gluon Plasma A new state of matter quarks & gluons get liberated from nucleons 20/41

24 Exploring properties of QCD medium in Heavy Ion Collisions What are the phases of strongly interacting matter and what roles do they play in cosmos? What does QCD predict for the properties of strongly interacting matter? Experimentally, are designed to address the above two fundamental questions Schematic QCD phase diagram for nuclear matter Theoretically, Lattice QCD gives first-principles calculations of nuclear physics 21/41

temperature required to form QGP initial state QGP and hydrodynamic expansion hadronic phase and freeze-out pre-equilibrium hadronization RHIC: Tavg=221±19±19 MeV PHENIX: Phys.Rev.Lett.

25 temperature required to form QGP initial state QGP and hydrodynamic expansion hadronic phase and freeze-out pre-equilibrium hadronization RHIC: Tavg=221±19±19 MeV PHENIX: Phys.Rev.Lett.104:132301,2010 LHC: Tavg=304±51 MeV ALICE: Nucl. Phys. A (2013) 573c M. Wilde, Nucl. Phys. A (2013) 573c Are these temperatures high enough to form a Quark Gluon Plasma? 22/41

[HotQCD collaboration], Phys. Rev. Lett.

相变温度为155(1)(8) MeV 工作被美国物理学会物理观点栏目专题报道 Gert Aarts,

26 [HotQCD collaboration], Phys. Rev. Lett.113(2014) 手征磁化率 HotQCD collaboration: Bielefeld University, BNL, CCNU, Columbia University, INT, LLNL, LANL 第一次利用了在有限格点间距下保持夸克对称性的格点 QCD得到了QCD平滑过渡相变温度为155(1)(8) MeV 工作被美国物理学会物理观点栏目专题报道 Gert Aarts, viewpoint for PRL, Physics 7, 86 (2014) 确定了RHIC & LHC中产生的温度足够高可以使强相互作用核物质发生相变 23/41

27 Deconfinement aspects of QCD transition Light-quark hadrons get deconfined around Tc, charmonia and bottomonia may survive at T>Tc Matsui & Satz PLB 86 How about open charm & strange hadrons? nd & 4th order cumulants of quark number fluctuations Strange quark, less affected by chiral symmetry, may remain confined at T > Tc? Do strange hadrons survive at higher temperature? Freeze-out/hadronization hierarchy between light-quark & strange hadrons? Tc=154(9) MeV HotQCD, PRD85(2012) Wuppertal-Budapest, JHEP 1009 (2010) u 2 s c N =8 0.2 T [MeV] N =8 u c s 4 T [MeV] /41

28 fluctuations of conserved quantum numbers In the confined hadronic phase: electric charge Q, baryon number B of hadrons are integer numbers In the deconfined QGP phase: Q and B of quarks are fractional numbers fluctuations of B/Q/S/C and their correlations: probe the deconfined degrees of freedom for strange (S) and charm (C), irrespective of quark mass XY mn p(ˆµ X, ˆµ Y )/T ˆµ m ˆµn Y ~µ =0, μ=μ/t, ^ X,Y={B,Q,S,C} order parameters : construct observables that vanish in one phase and are nonzero in the other phase Bazavov, HTD et al., Phys.Rev. Lett. 111(2013) /41

Partial pressure of heavy-light hadrons from HRG In the Hadron Resonance Gas (HRG) model, open heavy (strange or charm) mesons and baryons follow Boltzmann statistics as m/t >>1 P M/B (T,~µ) = X i2

29 Partial pressure of heavy-light hadrons from HRG In the Hadron Resonance Gas (HRG) model, open heavy (strange or charm) mesons and baryons follow Boltzmann statistics as m/t >>1 P M/B (T,~µ) = X i2 open C/S hadrons differences of baryon-x correlations (X=Q,S,C): BX 31 BX 11 = X i (B 3 i B i ) g i (m hadron ) if B=0,1, degrees of freedom are hadrons, if B=1/3, degrees of freedom are quarks, P i M/B cosh(b i ˆµ B + Q i ˆµ Q + S i ˆµ S + C i ˆµ C ) BX 31 = BX 11 BX 31 6= BX 11 depends on hadron spectrum the decomposition of partial pressure arising from open charm baryons P C B (T,~µ) =B C,1 + B C,2 + B C,3 BC mn = B C,1 +2 n B C,2 +3 n B C,3 PB is dominated by C =1 baryons due to large mass of C =2,3 baryons m+n>2 and even in the hadronic phase: BC mn ' B C,1, e.g. BC 13 ' BC 22 26/41

30 deconfinement of open charm & strange hadrons f QCD, N τ =8 HISQ data, m π =160 MeV, quenched charm un-corr. hadrons BC BC 22 / 13 BS BS 31 / 11 BQ BQ 31 / 11 T [MeV] ratio of baryon-charm correlation: receives contributions only from charm d.o.f ratio of baryon-strangeness correlation: receives contributions only from strange d.o.f ratio of baryon-charge correlation: receives contributions from all quark d.o.f all equal to unity in an uncorrelated hadron resonance gas Both open strange and charm hadrons start to get deconfined in the chiral crossover region A. Bazavov, HTD et al., [BNL-Bielefeld-CCNU], Phys. Lett. B 737(2014)210 27/41

31 编辑建议发表文章额外的奇异强子的热力学贡献和! 对实验中的冻结条件的影响 BNL-Bielefeld-CCNU collaboration comments from the Editor abstract 实验上尚未观测到的粒子特别是那些奇异强子, 让我们理解了格点量子色动力学在 QGP 相变附近的计算结果 28/41

32 Hadron Resonance Gas model: revisited P total = X all hadrons P h Quark Model Ebert et. al., EPJC66(2010)197, PRD84(2011) hadrons listed in PDG +??? More states are predicted in relativistic Quark Model (QM) than listed in PDG LQCD calculations give similar results with QM Lattice QCD Any thermodynamic significance from additional hadron states predicted in QM? Padmanath et.al., arxiv: [hep-lat] 29/41

33 Additional open strange hadrons in HRG Boltzmann approximation: P S,X M/B (T,~µ) = T X 2 2 i2x g i mi T with X=QM, PDG and μ=μ/t ^ 2 K2 (m i /T ) cosh(b i ˆµ B + Q i ˆµ Q + S i ˆµ S ) P PDG : 利用实验上已经观测到的粒子的谱 (PDG) 计算得到的压强 P QM : 利用夸克模型预言的粒子的谱 (QM) 做计算得到的压强 P B S,QM /PB S,PDG S,QM S,PDG P tot /Ptot S,QM S,PDG P M /PM B: pressure from baryons! M: pressure from mesons T [MeV] strange baryons experimentally much less known, additional baryons contribute up to 30% open strange mesons experimentally well known /41

34 Additional open charm hadrons in HRG B: pressure from baryons! M: pressure from mesons Less baryons than mesons! are listed in PDG charm sector The additional states from the Quark Model (QM) give considerable contributions to partial pressures at T<154 MeV A. Bazavov, HTD et al., [BNL-Bielefeld-CCNU], PRL 14, PLB 14 31/41

35 Construction of observables to probe the abundance decomposition of partial pressure (P) arising from heavy-light hadrons in HRG: P M/B (T,~µ) = charm sector: X i2 open C/S hadrons P i M/B cosh(b i ˆµ B + Q i ˆµ Q + S i ˆµ S + C i ˆµ C ) P C M (T,~µ) =M C, P C B (T,~µ) =B C,1 + B C,2 + B C,3 BC mn = B C,1 +2 n B C,2 +3 n B C,3 ' B C,1 partial P arising from baryons C n = M C + B C,1 +2 n B C,2 +3 n B C,3 ' M C + B C,1 with n even C n BC mn ' M C partial P arising from mesons observables probing the relative contribution of baryons and mesons to the partial pressures BC mn/( C n BC mn), e.g. BC 13 /( C 4 BC 13 ) 32/41

Abundance of open charm hadrons 2+1f QCD,N τ =8 HISQ data, m π =160 MeV Use appropriate projections to check the relative contributions of: charm baryons to open charm mesons Tc=154±9 MeV charged

36 Abundance of open charm hadrons 2+1f QCD,N τ =8 HISQ data, m π =160 MeV Use appropriate projections to check the relative contributions of: charm baryons to open charm mesons Tc=154±9 MeV charged charm baryons to open charm mesons strange-charmed baryons to strange-charmed mesons Clear evidence of the additional, non- PDG listed states from QCD thermodynamics is found A. Bazavov, HTD et al., [BNL-Bielefeld-CCNU], Importance of additional states has also been pointed out in Majumder and Mueller, PRL 105(2010) & Beitel, Gallmeister and Greiner, /41

37 Relative contributions of strange baryons to open strange mesons BS S 11 / B 1 S /M1 S B 2 S /M2 S B 2 S /M1 S strange-baryon! correlations partial! pressures cont. est. PDG-HRG QM-HRG N =6: open symbols N =8: filled symbols T [MeV] PDG-HRG: 利用实验上已经观测到的粒子的谱做的计算 { QM-HRG: 利用夸克模型预言的粒子的谱做的计算实验上已经观测到的粒子 } 夸克模型预言的粒子 { } 找到了实验上未观测到的粒子对 QCD 相变贡献的证据 A. Bazavov et al.[bnl-bielefeld-ccnu], Phys. Rev. Lett. 113 (2014) /41

38 strangeness chemical potential in HIC strangeness neutrality in HIC: NS=0 enforces dependence of μs on μb and T expand μs/μb in a Taylor series of μb: µ S µ B ' BS 11 S 2 (µ S /µ B ) LO QS 11 S 2 µ Q µ B + O(µ 2 B) T [MeV] NLO corrections are small at μb <200 MeV additional states contribute to the relative abundance of strange baryons to open strange mesons In the strange hadron sector, the PDG-HRG based analyses give a larger freeze out temperature than QM-HRG and lattice QCD cont. est. PDG-HRG QM-HRG BS S QM-HRG: - 11 / 2 N =6: open symbols N =8: filled symbols A. Bazavov et al.[bnl-bielefeld-ccnu], Phys. Rev. Lett. 113 (2014) /41

39 strangeness chemical potential in HIC strangeness neutrality in HIC: NS=0 enforces dependence of μs on μb and T expand μs/μb in a Taylor series of μb: µ S µ B ' BS 11 S 2 (µ S /µ B ) LO QS 11 S 2 µ Q µ B + O(µ 2 B) T [MeV] NLO corrections are small at μb <200 MeV additional states contribute to the relative abundance of strange baryons to open strange mesons In the strange hadron sector, the PDG-HRG based analyses give a larger freeze out temperature than QM-HRG and lattice QCD LQCD & QM-HRG! PDG- HRG cont. est. PDG-HRG QM-HRG BS S QM-HRG: - 11 / 2 N =6: open symbols N =8: filled symbols A. Bazavov et al.[bnl-bielefeld-ccnu], Phys. Rev. Lett. 113 (2014) /41

40 Hierarchy freeze out for light and strange hadrons? fit to all data - fit to all data w/o p(p) Andronic et al., Nucl. Phys. A904 (2013) 535c ~ 10-5 MeV systematic difference in the freeze out T from separate fits to light and strange hadrons using PDG-HRG two freeze out stages for light and strange hadrons? Alba et al., arxiv: ,bugaev et al., EPL 104(2013)22002,! Bellwied et al., [WB Collaboration], Phys.Rev. Lett. 111(2013)202302,! Chatterjee, Godbole, Gupta, PLB 727(2013)554 36/41

41 Strange hadron yields in HIC Two-parameter fit to experiment data using HRG ansatz R H H S H S =exp Log(RH) irrespective of the details of hadron spectrum / h / 2(µ f B /T f ) / 1 (µ fs /µfb ) S i imprinted by the presence of experimentally yet unobserved strange hadrons GeV (STAR prlim) 17.3 GeV (NA57) Compare the extracted μs/μb and μb/t with those from HRG & Lattice QCD S F. Antinori et al.,plb 595(2004)68, F. Zhao, PoS CPOD2013(2013)036 37/41

42 Imprints of unobserved states in strangeness freeze out in HIC µ S /µ B T=161 MeV T=158 MeV T=155 MeV LQCD: T=155(5) MeV LQCD: T=145(2) MeV PDG-HRG QM-HRG 39 GeV (STAR prlim.) 17.3 GeV (NA57) T=149 MeV T=170 MeV T=147 MeV T=145 MeV T=166 MeV T=162 MeV T=155 MeV µ B /T T=152.5 MeV T=150 MeV In the strange sector, the PDG-HRG based analysis give larger freeze out temperature than QM-HRG & LQCD by about 5-8 MeV QM-HRG should be the preferable choice to determine freeze out temperature at large μb where LQCD is not applicable A. Bazavov et al.[bnl-bielefeld-ccnu], Phys. Rev. Lett. 113 (2014) /41

Summary & Outlook 退禁闭相温度禁闭相 un-corr. hadrons 1.0 0.30 BC 22 / BS 31 / BQ 31 / 0.8 0.6 µs/µb BC 13 BS 11 BQ 11 0.25 0.20 0.

43 Summary & Outlook 退禁闭相温度禁闭相 un-corr. hadrons BC 22 / BS 31 / BQ 31 / µs/µb BC 13 BS 11 BQ T [MeV] 重子化学势 T=166 MeV T=158 MeV T=162 MeV T=155 MeV T=170 MeV T=161 MeV LQCD: T=155(5) MeV LQCD: T=145(2) MeV PDG-HRG QM-HRG 39 GeV (STAR prlim.) 17.3 GeV (NA57) T=149 MeV T=147 MeV T=145 MeV V Me 5 15 T= MeV T=1 V 0 Me 5 1 = T µb/t /41

44 arxiv: Initial state Initial conditions Jets and heavy flavor Deconfinement, quarkonia and hadronization Phase diagram Collectivity and system size 40/41

45 Summary & Outlook 退禁闭相? 温度禁闭相 m s 2 nd order O(4) N f =2 2 nd order Z(2) PURE 1 st order GAUGE 温度 m tri s physical point cross over N f =3 N f =1 m c QCD 临界点 1 st order 2 nd order Z(2) 重子化学势 m u,d 41 /41

46 Summary & Outlook 退禁闭相? 温度禁闭相 m s 2 nd order O(4) N f =2 2 nd order Z(2) PURE 1 st order GAUGE 温度 m tri s physical point cross over N f =3 N f =1 m c QCD 临界点 1 st order 2 nd order Z(2) 重子化学势 m u,d 41 /41

The strange degrees of freedom in QCD at high temperature. Christian Schmidt

The strange degrees of freedom in QCD at high temperature Christian Schmidt Christian Schmidt LAT 213 1 Abstract We use up to fourth order cumulants of net strangeness fluctuations and their correlations