Probing Transverse Momentum Broadening via Dihadron & Hadron-jet Angular Correlations. Shu-yi Wei (CCNU)

Transcription

1 Har Probes, 6 Probing Transverse Momentum Broaening via Diharon & Haron-jet Angular Correlations Shu-yi Wei (CCNU) In collaboration with L. Chen, G.Y. Qin, B.W. Xiao & H.Z. Zhang arxiv:67.93

2 Contents Introuction Suakov Resummation ˆq Extract from iharon & haron-jet correlations Summary

3 Introuction: Jet Quenching Jet-meium interaction k broaening Energy loss Two sies of the same coin. BDMPS approach Jet transport parameter ˆq = k? L E x = sn c ˆqL ˆq reflects the ensity of QGP Baier, Dokshitzer, Mueller, Peigne, an Schiff NPB 83 (997), 8 (997), 53(998). Shu-yi Wei (CCNU) Har Probes - Wuhan 3

4 Introuction Energy loss - Single haron RAA q/t ˆ MARTINI HT-BW HT-M McGill-AMY GLV-CUJET ˆq. ±.3.9 ±.7 GeV /fm at T=37 MeV, T=7 MeV, for a GeV quark JET qˆ N /T 3 eff(dis) Au+Au at RHIC Pb+Pb at LHC T (GeV) Jet Collaboration. PRC 9, 99, () Angular ecorrelation - New an complimentary metho Extract ˆq via angular ecorrelation in the back-to-back region. Shu-yi Wei (CCNU) Har Probes - Wuhan

5 Introuction Diharon Angular RHIC back-to-back region /N trigger N/( φ)..5.. a) b) c) p+p opposite sign Minimum Bias Au+Au -% Au+Au same sign η <.5 η > φ(raians) STAR, PRL 9, (3) I AA Away-Sie Au+Au GeV (-%) ± Qin[γ -h ] ir ± ZOWW[γ -h ] ir ± ZOWW[ π -h ] < p trig T < GeV/c p STAR, PLB76 (6) z T ± γ -h ir ± π -h Renk[γ assoc T ± -h ir, p trig T = 9- GeV/c] >. GeV/c Yiel suppression Angular ecorrelation: quantitative calculation is lacking Shu-yi Wei (CCNU) Har Probes - Wuhan 5

6 Introuction ATLAS [PRL 5, ()] & CMS [PRC 8, ()] ) N/A (/N J evt 3 -% ) N/A (/N J evt 3 -% ) N/A (/N J evt 3 -% ) N/A (/N J evt 3 s NN =.76 TeV -% ATLAS Pb+Pb - L int =.7 µb p T A J p T p T + p T A J A J A J A J ) N/ φ evt ) N/ φ evt ) N/ φ evt ) N/ φ evt Pb+Pb Data p+p Data HIJING+PYTHIA (/N (/N (/N (/N φ.5 3 φ.5 3 φ.5 3 φ peripheral Energy imbalance increases: Energy Loss No clear sign of angular ecorrelation Qin, Muller, PRL 6 () Is ˆq '? central Puzzle: Large Energy Loss, Small pt Broaening? Shu-yi Wei (CCNU) Har Probes - Wuhan 6

7 Suakov Resummation Dijet angular correlation in pp /σ σ/φ max 75 < P T < (GeV) Perturbative Expansion, 3, - large logarithms ( s ln p T q? ) n Not Stable paraigm shift - Suakov Resummation resummation full NLO φ (ra) + n Soft gluon raiations (parton shower) p p at p s =.76 TeV Tevatron Sun, Yuan, Yuan, PRL3 (), PRD9 (5) Shu-yi Wei (CCNU) Har Probes - Wuhan 7

8 Suakov Resummation Central rapiity back-to-back ijet prouction p T l T l T Picture: Inertia Kinematic region: p T ~q? = ~p T + ~p T ~p T ' ~p T small angle Back-to-back correlations are very sensitive to the soft gluon raiations. Shu-yi Wei (CCNU) Har Probes - Wuhan 8

9 Suakov Resummation From pp to AA Mueller, Wu, Xiao, Yuan, arxiv: Consiering one gluon raiation in the large meium, Meium Inuce Raiation an Vacuum Parton Shower can be separate. l + /q + l = ^q τ l A+B cancel τ l = L ^q t Suakov τ l = τ q B+C cancel τ l = r ql ^ ql ^ /x Q l S AA (Q, b) =S pp (Q, b)+ hˆqlib hot meium Vacuum parton shower kt broaening Multiple scattering Meium inuce raiation Shu-yi Wei (CCNU) Har Probes - Wuhan 9

10 Suakov Resummation Dijet angular correlation in AA N N 6 Dijet Angular Correlation at the LHC CMS - % ˆqL =GeV ˆqL =8GeV ˆqL =GeV S AA (Q, b) =S pp (Q, b)+ hˆqlib p SNN =.76 TeV p T > 5 GeV p T > 5 GeV Vacuum Suakov Effect Meium Broaening Effect This explains why the LHC i not observe the angular ecorrelation. Mueller, Wu, Xiao, Yuan, arxiv:6.5 Shu-yi Wei (CCNU) Har Probes - Wuhan

11 Suakov Resummation Dijet angular correlation in AA N N 6 Dijet Angular Correlation at RHIC ˆqL =GeV ˆqL =8GeV ˆqL =GeV S AA (Q, b) =S pp (Q, b)+ hˆqlib p SNN = GeV p T > 35 GeV p T > 5 GeV Vacuum Suakov Effect ~ Meium Broaening Effect Decrease the center of mass energy or measure small pt jet. Mueller, Wu, Xiao, Yuan, arxiv:6.5 Shu-yi Wei (CCNU) Har Probes - Wuhan

12 Diharon & haron-jet correlations Diharon correlations in pp - Establish Baseline.. 3. STAR pp [, ]+[3, 5] hˆqli =GeV 3. PHENIX pp [5, ]+[5, ] hˆqli =GeV For the first time we can escribe the back-to-back angular correlation. 3.. PHENIX pp [5, ]+[3, 5] hˆqli =GeV Establishe a baseline to stuy the angular ecorrelation in AA collisions Shu-yi Wei (CCNU) Har Probes - Wuhan

13 Diharon & haron-jet correlations pp collisions + AA collisions. 3. PHENIX pp PHENIX AA -% hˆqli =GeV hˆqli =7GeV. 3. PHENIX pp PHENIX AA -% hˆqli =GeV hˆqli =7GeV. 3. STAR pp STAR AA -% hˆqli =GeV hˆqli =7GeV iharon. p trig T,h =[5, ] GeV p asso T,h =[3, 5] GeV. p trig T,h =[5, ] GeV p asso T,h =[5, ] GeV. p trig T,h =[, ] GeV p asso T,h =[3, 5] GeV haron-jet.. p trig T,h =[9, 3] GeV =[, 8] GeV p asso T,J STAR 6-8% STAR -% hˆqli =GeV hˆqli =7GeV.. p trig T,h =[9, 3] GeV =[8, 8] GeV p asso T,J STAR 6-8% STAR -% hˆqli =GeV hˆqli =7GeV.. p trig T,h =[, 5] GeV =[6, 9] GeV p asso T,J ALICE TT[, 5] -% ALICE TT[, 5]-[8, 9] hˆqli =GeV hˆqli =7GeV hˆqli =GeV Shu-yi Wei (CCNU) Har Probes - Wuhan 3

14 Diharon & haron-jet correlations Normalize q istributions. RHIC HJ [9, 3]+[, 8].5 HJ [9, 3]+[8, 8] HH [5, ]+[3, 5] q?..5 HH [5, ]+[5, ] HH [, ]+[3, 5] LHC HJ [9, 3]+[8, 8] HJ [, 5]+[6, 9] HH [5, ]+[5, ] q?aa ' q?pp + hˆqli q? (GeV) Large pt events are not sensitive to the meium inuce kt broaening, since the vacuum Suakov effect is too large. Shu-yi Wei (CCNU) Har Probes - Wuhan

15 Diharon & haron-jet correlations 5 HJ[9, 3]+[, 8] Global fit with RHIC ata HJ[9, 3]+[8, 8] HH[5, ]+[3, 5] HH[5, ]+[5, ] HH[, ]+[3, 5] /.o.f 3 Global fit S AA (Q, b) =S pp (Q, b)+ hˆqlib hˆqli tot = + GeV 3 hˆqli(gev ) larger than the value, extracte from single haron RAA by JET Collaboration ˆq =. ±.3 GeV /fm Raiative correction Effective length Shu-yi Wei (CCNU) Har Probes - Wuhan 5

16 Summary For the first time we can escribe the back-to-back iharon/haron-jet angular correlation measure at RHIC & LHC. The ijet, iharon an haron-jet angular correlations can provie a new gateway to quantify the meium inuce kt broaening. We extracte that hˆqli tot = + GeV for a quark jet at RHIC energy. Outlook Energy loss. Diharon per trigger yiel. AJ istribution. Shu-yi Wei (CCNU) Har Probes - Wuhan 6

17 Summary Outlook For the first time we can escribe the back-to-back iharon/haron-jet angular correlation measure at RHIC & LHC. The ijet, iharon an haron-jet angular correlations can provie a new gateway to quantify the meium inuce kt broaening. We extracte that Energy loss. Diharon per trigger yiel. AJ istribution. hˆqli tot = + GeV for a quark jet at RHIC energy. Thanks for your attention! Shu-yi Wei (CCNU) Har Probes - Wuhan 7

18 The En

19 Suakov Resummation Diharon azimuthal angle correlation = X a,b,c, Z p h T ph T Z p h T ph T (Chen, Qin, Wei, Xiao, Zhang, arxiv:67.93) Z zc z c Z z z Z bb J (q? b)e S(Q,b) x a f a (x a,µ b )x b f b (x b,µ b ) ab!c ˆt D c (z c,µ b )D (z,µ b ) Haron-JET azimuthal angle correlation = X a,b,c, Z p h T ph T Z k j? kj? Z z z Z bb J (q? b)e S(Q,b) x a f a (x a,µ b )x b f b (x b,µ b ) ab!c ˆt D c (z,µ b ) Suakov factor initial & final state parton shower S(Q, b) =S pert (Q, b)+s non pert (Q, b)+s meium (hˆqli,b) Broken universality factorization breaks own higher twist PDFs an FFs Shu-yi Wei (CCNU) Har Probe Wuhan 9

20 Suakov Resummation Suakov factor S(Q, b) =S pert (Q, b)+s non pert (Q, b)+s meium (hˆqli,b) S i pert = X i=a,b Z Q µ b µ µ apple Q A i ln µ + B i initial state Suakov factor S f pert = X f=c, Z Q µ b µ µ apple Q A f ln µ + B f for f is a haron S f pert = X f=c, Z Q µ b µ µ apple D f ln R for f is a JET Non-perturbative Suakov factor preictive power Not universal for iharon, haron-jet an ijet prouctions. Universal for ifferent pt regions or CME for the same process. Snp = C Snp DIS C = 5 for iharon prouction C = for haron-jet prouction Shu-yi Wei (CCNU) Har Probe Wuhan