New insights of soft hadron production in pp and p-Pb collisions at - PowerPoint PPT Presentation

New insights of soft hadron production in pp and p-Pb collisions at LHC Jun Song （宋军） Jining University (Qufu, Shandong ) Collaborators : Feng-lan Shao, Zuo-tang Liang, Xing-rui Gou, Hai-hong Li, et al Outline 1. Motivation 2. Quark number scaling property for hadron 𝒒 𝑼 spectra 3. Quark combination mechanism in pp and p-Pb collisions at LHC 4. Summary 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018)

Motivation p-p Pb-Pb p-Pb Recently, striking features observed by ALICE, CMS, LHCb collaborations for high multiplicity events in pp and p-Pb collisions at LHC, e.g, • long range angular correlations (ridge), CMS JHEP1009(2010), CMS PLB718(2013),742(2015) • flow-like patterns, NPA932(14), CMS PLB742(2015),765(2017) • enhanced strangeness, ALICE Nature Phys.13(2017) • enhanced baryon/meson ratios, …… Is Quark Gluon Plasma (QGP) also formed in pp and p-Pb collisions at LHC? Theoretical explanations focus on the creation of mini-QGP or phase transition, color re- connection or string overlap at hadronization Our studies suggest the change of hadronization mechanism from fragmentation to quark combination ! 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 2

Quark number scaling of hadronic 𝒒 𝑼 spectra Song,Gou,Shao,Liang, Phys.Lett. B774(2017),516 Manipulate data of 𝒒 𝑼 spectra of 𝛁(𝐭𝐭𝐭) and 𝝔(𝒕ത 𝒕) in p-Pb collisions at 5.02 TeV (1) divide 𝒒 𝑼 bin by quark number, 𝒒 𝑼 𝛁 /3, 𝒒 𝑼 𝝔 /2, (2) take the inverse quark number power of density 𝒆𝑶 𝒊 /𝒆𝒒 𝑼 𝒆𝒛 , 𝟐/𝟒 /𝒆𝒒 𝑼 𝒆𝒛 and 𝒆𝑶 𝝔 𝟐/𝟑 /𝒆𝒒 𝑼 𝒆𝒛 i.e. 𝒆𝑶 𝜵 (3) divide 𝛁 data by a constant to keep the same magnitude with that of 𝝔 𝒈 𝒒 𝑼 ≡ 𝒆𝑶 𝒊 /𝒆𝒒 𝑼 𝒆𝒛 mathematic relation 𝟐/𝟒 𝟒𝒒 𝑼 = 𝝀 𝝔,𝛁 𝒈 𝝔 𝟐/𝟑 (𝟑𝒒 𝑼 ) 𝒈 𝛁 in other words, 𝟒 𝒒 𝑼 𝒈 𝛁 𝟒𝒒 𝑼 = 𝝀 𝛁 𝒈 𝒕 𝟑 𝒒 𝑼 𝒈 𝝔 𝟑𝒒 𝑼 = 𝝀 𝝔 𝒈 𝒕 p-Pb 5.02TeV where 𝜆 is independent of 𝑞 𝑈 𝑞 𝑈 (GeV/c) ALICE data : Phys. Lett. B 758, 389(2016). Eur. Phys. J. C76, 245 (2016) 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 3

Scaling property in different multiplicity classes in p-Pb collisions at 5 TeV high multiplicity events QNS holds well small multiplicity events QNS is broken Scaling property at different multiplicity classes 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 4

Scaling property in different multiplicity classes in pp collisions at 7 TeV pp at 7TeV pp at 7TeV high multiplicity events QNS holds well pp at 7TeV pp at 7TeV small multiplicity events QNS is broken 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 5

Scaling property in pp collisions at different collision energies 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 6

Scaling property between Ξ ∗0 (𝑣𝑡𝑡) and 𝐿 ∗0 (𝑒 ҧ 𝑡) 𝑔 Ξ ∗0 ( 2 + 𝑠 𝑞 𝑈 ) = 𝜆 𝐿 ∗ ,Ξ ∗ 𝑔 𝑡 (𝑞 𝑈 ) 𝑔 𝐿 ∗0 1 + 𝑠 𝑞 𝑈 where 𝑠 ≈ 2/3 𝑞 𝑈 (GeV/c) ALICE data, Eur. Phys. J. C77, 389(2017) 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 7

Quark Combination Mechanism Quark number scaling property exhibited is a clear signal of quark combination hadronization for small parton system created in pp and p-Pb collisions at LHC energies Start from general formula 𝑔 𝐶 𝑘 𝑞 𝐶 = ∫ 𝑒𝑞 1 𝑒𝑞 2 𝑒𝑞 3 𝑆 𝐶 𝑘 𝑞 1 , 𝑞 2 , 𝑞 3 ; 𝑞 𝐶 𝑔 𝑟 1 𝑟 2 𝑟 3 𝑞 1 , 𝑞 2 , 𝑞 3 𝑔 𝑁 𝑘 𝑞 𝑁 = ∫ 𝑒𝑞 1 𝑒𝑞 2 𝑆 𝑁 𝑘 𝑞 1 , 𝑞 2 ; 𝑞 𝑁 𝑔 𝑟 2 𝑞 1 , 𝑞 2 𝑟 1 ത Assume independent distribution of (anti-)quarks 𝑔 𝑟 1 𝑟 2 𝑟 3 𝑞 1 , 𝑞 2 , 𝑞 3 = 𝑔 𝑟 1 𝑞 1 𝑔 𝑟 2 𝑞 2 𝑔 𝑟 3 𝑞 3 𝑔 𝑟 2 𝑞 1 , 𝑞 2 = 𝑔 𝑟 1 𝑞 1 𝑔 ത 𝑟 2 𝑞 2 𝑟 1 ത Adopt the co-moving combination 3 equal velocity combination 𝑆 𝐶 𝑘 𝑞 1 , 𝑞 2 , 𝑞 3 ; 𝑞 𝐶 = 𝜆 𝐶 𝑘 ෑ 𝜀(𝑞 𝑗 − 𝑦 𝑗 𝑞 𝐶 ) 𝒚 𝒋 = 𝒏 𝒋 / σ 𝒌 𝒏 𝒌 , 𝑗=1 2 𝑛 𝑡 = 500 MeV 𝑆 𝑁 𝑘 𝑞 1 , 𝑞 2 ; 𝑞 𝑁 = 𝜆 𝑁 𝑘 ෑ 𝜀(𝑞 𝑗 − 𝑦 𝑗 𝑞 𝑁 ) 𝑛 𝑣 = 𝑛 𝑒 = 330 MeV. 𝑗=1 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 8

adopt flavor-blind approximation Rewrite the spectrum ഥ (𝑜) 𝑞 𝑁 𝑂 𝑁 𝑔 𝑁 𝑘 𝑞 𝑁 = 𝑂 𝑁 𝑘 𝑔 𝑄 𝑟 1 ത 𝑟 2 →𝑁 𝑘 = 𝐷 𝑁 𝑘 𝑁 𝑘 𝑂 𝑟 ത (𝑜) 𝑞 𝐶 𝑟 𝑔 𝐶 𝑘 𝑞 𝐶 = 𝑂 𝐶 𝑘 𝑔 ഥ 𝐶 𝑘 𝑂 𝐶 𝑄 𝑟 1 𝑟 2 𝑟 3 →𝐶 𝑘 = 𝐷 𝐶 𝑘 𝑂 𝑟𝑟𝑟 with normalized distribution ∫ 𝑒𝑞 𝑔 𝑜 𝑞 = 1 , (𝑜) 𝑞 𝑁 = 𝐵 𝑁 𝑘 𝑔 (𝑜) 𝑦 1 𝑞 𝑁 𝑔 ത (𝑜) 𝑦 2 𝑞 𝑁 𝑔 𝐷 𝑁 𝑘 and 𝐷 𝐶 𝑘 select the different spin states 𝑟 1 𝑁 𝑘 𝑟 2 (𝑜) 𝑞 𝐶 = 𝐵 𝐶 𝑘 𝑔 (𝑜) 𝑦 1 𝑞 𝐶 𝑔 (𝑜) 𝑦 2 𝑞 𝐶 𝑔 (𝑜) 𝑦 3 𝑞 𝐶 𝑔 for the same flavor combination 𝐶 𝑘 𝑟 1 𝑟 2 𝑟 3 , and yield 1 𝑔𝑝𝑠 𝐾 𝑄 = 0 − 𝑛𝑓𝑡𝑝𝑜𝑡 1 + 𝑆 𝑊/𝑄 𝜆 𝑁𝑘 𝐷 𝑁 𝑘 = 𝑂 𝑁 𝑘 = 𝑂 𝑟 1 ത = 𝑂 𝑟 1 ത 𝑟 2 𝑄 𝑟 1 ത 𝑆 𝑊/𝑄 𝑟 2 𝑟 2 →𝑁 𝑘 𝑔𝑝𝑠 𝐾 𝑄 = 1 − 𝑛𝑓𝑡𝑝𝑜𝑡 𝐵 𝑁𝑘 1 + 𝑆 𝑊/𝑄 𝜆 𝑁𝑘 𝑂 𝐶 𝑘 = 𝑂 𝑟 1 𝑟 2 𝑟 3 = 𝑂 𝑟 1 𝑟 2 𝑟 3 𝑄 𝑟 1 𝑟 2 𝑟 3 →𝐶 𝑘 𝑆 𝑃/𝐸 𝑔𝑝𝑠 𝐾 𝑄 = (1/2) + 𝑐𝑏𝑠𝑧𝑝𝑜𝑡 𝐵 𝑁𝑘 1+𝑆 𝑃/𝐸 𝐷 𝐶 𝑘 = ൞ 1 𝑔𝑝𝑠 𝐾 𝑄 = (3/2) + 𝑐𝑏𝑠𝑧𝑝𝑜𝑡 1+𝑆 𝑃/𝐸 𝑄 𝑟 1 ത 𝑟 2 →𝑁 𝑘 and 𝑄 𝑟 1 𝑟 2 𝑟 3 →𝐶 𝑘 are momentum- Parameters 𝑆 𝑊/𝑄 = 0.45 𝑆 𝑃/𝐸 = 2.0 integrated combination probabilities 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 9

QCM in p-Pb collisions at 5.02 TeV Song,Gou,Shao,Liang, Phys.Lett. B774(2017),516 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 10

Gou,Shao,Song …,PRD96(2017), 094010 QCM in pp collisions at 7 TeV Minimum bias events 𝑞 𝑈 (GeV/c) 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 11

Zhang,Shao,Song,arXiv:1811.00975 QCM in pp collisions at 13 TeV 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 12

Production of single-charm hadrons in pp and p-Pb collisions at LHC Song, Li, Shao, Eur.Phys.J. C78 (2018) 344 Li, Shao,Song, PRC97(2018), 064915 Equal-velocity combination of charm quark and light-flavor (anti)quarks Quark spectra at hadronization got from light-flavor hadrons consistent with pQCD calculations Parameters in the model: 𝑆 𝑊/𝑄 = 1.5 𝑆 𝑇3/𝑇1 = 1.5 thermal weights 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 13

Song, Li, Shao, Eur.Phys.J. C78 (2018) 344 Li, Shao,Song, PRC97(2018), 064915 D mesons of 𝒒 𝑼 ≲ 8 GeV, = 𝒅 quark of 𝒒 𝑼,𝒅 ≲ 𝟕 + l quark of 𝒒 𝑼,𝒎 ≲ 𝟑 GeV 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 14

Song, Li, Shao, Eur.Phys.J. C78 (2018) 344 Li, Shao,Song, PRC97(2018), 064915 𝒒 𝑼 dependence of charmed Baryon/Meson ratio p-Pb 5.02TeV p-Pb 5.02TeV 1.5<y<4 pp 7TeV 𝑞 𝑈 (GeV/c) 𝑞 𝑈 (GeV/c) 2018/12/21 Wuhan Wuhan The 4t he 4th China h China LHC Ph LHC Physics ysics Wo Workshop ( rkshop (ATHIC ATHIC 2018) 2018) 15