resonances from jets

126th Winter Workshop, Ocho Rios, Jamaica January 2010

Christina MarkertUniversity of Texas at Austin

• Introduction• Resonances in Medium• Resonances from Jets• Conclusions

Christina Markert, UT Austin

Temperature

Quark Gluon Plasma

Hadron Gas

T Freeze

Shuryak QM04

Baryochemical potential

part

on

s

Tc

hadro

ns

Resonance Production in Heavy Ion Collisions

2.)

Preequili-brium

QGP MixedPhase

3.)

1.)

Hadron gas

TcTi TkinTchem

Mixed dof

1.) Most resonances (u,d,s) are formed when partonic matter transitions

back into hadronic matter 2.) Formation of resonances in

hadronic matter due to regeneration3.) Resonances created from a jet

within the QGP phase (mixed dof Phase) potentially

survive in partonic matter (QGP)



Time Evolution of Heavy Ion Reactions

TchemicalTchemical

> 3-5 fm/cresonances

~ 10 fm/c2 particle correlation

Pre-equilibrium : < 1fm/c Partonic medium (QGP)QGP ~ 5 fm/c

Hadronic medium (HG)HG~ 5 fm/c

earlylate



Resonances below pT < 2 GeV/c interact with hadronic

medium(bulk matter)



Marcus Bleicher and Jörg Aichelin Phys. Lett. B530 (2002) 81 + private communication

Hot

and

den

se

med

ium

time

p

K

p

K

Resonance Suppression

[1] P. Braun-Munzinger et.al.,PLB 518(2001) 41, priv. communication[2] Marcus Bleicher and Jörg Aichelin Phys. Lett. B530 (2002) 81. M. Bleicher and Horst Stöcker J. Phys.G30 (2004) 111.

Phys. Rev. Lett. 97 (2006) 132301

Life-time [fm/c] :K(892) = 4.0 =(1520) = 13 (1020) = 45

[2][1]





STAR Preliminary

A Lordanova SQM2007

Fluctuations of K and from K* scattering in hadronic phaseReconstructed K* resonances are from non-scattered decay particles (K.)Indication of small hadronic phase, but errors are still large ?*/ is better observable, more sensitive to hadronic lifetime due to smaller regeneration cross section (in progress)

G. Torrieri, R. Bellwied, C. Markert, G. WestfallarXiv:1001.0087

Resonances at lower Energies (SPS)

M. Mitrovski SQM2009

NA49 Preliminary



Model:HGMBecattini et al. PRC73 (2006) 044905

G. Torrieri and J. Rafelski, Phys. Lett. B509 (2001) 239

RHIC:T= 160 MeV => > 4 fm/c

SPS:T=160 MeV => > 6 fm/c (lower limit !!!)

Hadronic lifetime at SPS longerthan at RHIC energies?

UrQMD v2.3

UrQMD hadronic lifetime

UrQMDMarcus Bleicher and Jörg Aichelin Phys. Lett. B530 (2002) 81-87. M. Bleicher and Horstn Stöcker Phys.G30 (2004) 111. (S.Vogel)

The main Feature of Quantum Chromodynamics

• Confinement– Free quarks are not observed in nature.

• Asymptotic freedom– Under such conditions quarks and gluons appear to be quasi-free.

• (Hidden) chiral symmetry– Connected with the quark masses– In the small coupling limit (some) quarks have small mass -

current mass– When confined quarks have a large dynamical mass - constituent

mass Hadron Mass: Higgs mass (current mass) + QCD mass (dynamical mass)

Approaching ‘asymptotic freedom’ Dynamical mass decreasesHadron mass is decreasing

B.Mueller (2004): New Discoveries at RHIC

Measure Resonances without interaction in hadronic medium



Chiral symmetry restored

Di-electron Measurement (PHENIX)

A significant excess is observed at low mass in Au+Au minimum bias

p+p Au+Au minimum bias

Alberica Toia QM2008Low-Mass Continuum:enhancement 150 <mee<750 MeV: 3.4±0.2(stat.) ±1.3(syst.)±0.7(model)

arXiv:0706.3034Phys.Lett.B670:313-320



see WWND10:Sarah CampbellElena Bratkovskaya

We want early produced resonances and decay in chirally restored medium

resonances from jets

CM, R. Bellwied, I.Vitev, Phys.Lett.B669:92-97,2008

2.)

Preequili-brium

QGP MixedPhase

3.)

1.)

Hadron gas

TcTi TkinTchem

Mixed dof

1.) Most resonances (u,d,s) are formed when partonic matter transitions back into hadronic matter

2.) Formation of resonances in hadronic matter due to regeneration

3.) Resonances created from a jet within the QGP phase

(mixed dof Phase) potentially survive in partonic matter (QGP)

partonicmedium

hadrons/resonances

hadrons/resonances



10 GeV/c

Heavier particles of same momentum formed earlierHigh momentum particles formed later

light cone variables: large z (=ph / pq) = Resonance is leading particle in jetshortens formation timecolor neutral pre-hadron (resonance)

~ 4.5 fm/c

~ 1.5 fm/c

CM, R. Bellwied, I.Vitev, Phys.Lett.B669:92-97,2008



Formation Time of Resonances

At LHC the momentum range of resonances decaying inside QGP is extended to higher momentum due to longer

QGP lifetime

RHIC

LHC

(1020): RHIC pT= [3-10] GeV LHC pT=[2-20] GeV

Resonance needs to decay in the partonic or the dense hadronic medium: short lived resonances reconstruction difficult (broad states): Resonances are medium modified short lifetime modified K*, *, *, are good candidates

Holt & Haglin, J. Phys. G31 (2005)



Triggered Resonance (STAR) Cu+Cu (quadrant correlation analysis)

side 1

side 2

near

awaythermal resonances

near away

hadron-resonance correlation

Hadron trigger pT > 3 GeV (1020) asso pT =1-2 GeV

Width:7.2±0.9 MeVWidth:7.2±0.9 MeV

M(K+ K-) GeV/c2

First bin in delta phiWidth:6.0±0.7 MeVWidth:6.0±0.7 MeV

M(K+ K-) GeV/c2HQ2008

No evidence for mass shifts andwidth broadenings on the away-side

Most (1020) are from thermal medium (90%)Need higher pT resonances lot of events

needed

Φ(1020)Φ(1020)



Resonances at the LHC (ALICE)



ALICE EMCal Physics Performance Report Statistics for 1 month Pb+Pb data

Resonances from jets in ALICE



side 1

side 2

near

away

pythiaStatistics in Pb+Pb

jet trigger pT = [50,60] GeV/cresonance pT > 4 GeV/c

Resonance ratios in four quadrants



side 1

side 2

near

away

no interaction with hadronic medium for high pT and jet triggered resonances

side Low pT High pT

near no medium no medium

away hadronic medium K*/K suppression

Partonic or early hadronic medium if K*/K changes different modification of resonance FF

Pythia

K*/K

K*/K

K* Fragmentation Function Modification



ALICE EMCal Physics Performance Report Statistics for 1 month Pb+Pb data

Conclusions

Low pt resonances are sensitive to hadronic medium (lifetime).

High pt resonances from jets are sensitive to early medium and might probe Chiral Symmetry Restoration.

Measure modification of resonance FF.



resonances from jets

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