Overview of recent heavy-flavor results from STARmoriond.in2p3.fr/QCD/2017/FridayMorning/Ma.pdf ·...

Overview of recent heavy-flavor results from STAR

Rongrong Ma (BNL) for the STAR Collaboration

Quark-Gluon Plasma (QGP)

03/31/2017 Rongrong Ma (BNL), Moriond 2

•  Lattice-QCD predicts a phase transition from confined hadrons to the Quark Gluon Plasma (QGP) where quarks and gluons are deconfined. –  εc ~ 0.6 GeV/fm3; Tc ~ 150 MeV

2015 Long Range Plan

Quark-Gluon Plasma (QGP)


•  Have existed in early universe: t ~ 10-6s

•  Lattice-QCD predicts a phase transition from confined hadrons to the Quark Gluon Plasma (QGP) where quarks and gluons are deconfined. –  εc ~ 0.6 GeV/fm3; Tc ~ 150 MeV

2015 Long Range Plan

Probe QGP with Heavy Flavor


•  HEAVY: mc,b >> TQGP, ΛQCD –  Produced in high-Q2 scatterings à calculable in pQCD; scales with binary

nucleon-nucleon collisions in heavy-ion collisions –  Produced at early stage à imprint the entire evolution history of QGP





•  Open heavy flavor (Qq, Qqq) –  Radiative+collisional energy loss à transport coefficient

–  Collective behavior à spatial diffusion coefficient –  Hadronization mechanism, e.g. coalescence

ΔEg > ΔEu ,d ,s > ΔEc > ΔEb

“Brownian” motion

(q, e)





•  Open heavy flavor (Qq, Qqq) –  Radiative+collisional energy loss à transport coefficient

–  Collective behavior à spatial diffusion coefficient –  Hadronization mechanism, e.g. coalescence

ΔEg > ΔEu ,d ,s > ΔEc > ΔEb

“Brownian” motion

(q, e)

•  Quarkonium (QQ) –  Dissociation: QQ potential color-screened in the medium à

direct evidence of QGP formation •  However, deconfined quarks and anti-quarks can recombine

–  Sequential melting: different quarkonia dissociate at different temperatures à constrain medium temperature

The Solenoid Tracker At RHIC

Ø  HFT (2014-2016): measure track points •  Inner pixel layers (MAPS): high

resolution; low material budget

Ø  TPC: measure momentum and energy loss

Ø  TOF: measure particles’ flight time to enhance PID at low pT

Ø  BEMC: trigger on and identify high-pT electrons

Ø  MTD (2013-present): trigger on and identify muons •  |η| < 0.5, φ ~ 45% •  Less bremsstrahlung

03/31/2017 Rongrong Ma (BNL), Moriond

Muon Telescope Detector

Time Of Flight

•  Large acceptance: |η| < 1, 0 < φ < 2π

Barrel ElectroMagne9c Calorimeter

7

Time Projec9on Chamber

Heavy Flavor Tracker

(GeV/c)TTransverse Momentum p0 1 2 3 4 5 6 7 8

AAR

00.20.40.60.8

11.21.41.61.8 Au+Au 200GeV, 0-10%

20140D2010/110D

π (0-12%)

STAR Preliminary

p+p uncert.


STAR: PRL 113 (2014) 142301 STAR: PLB 655 (2007) 2014

•  Strong suppression of D0 meson at high pT à substantial energy loss of charm quarks due to strong interactions with the medium

•  RAA(D0) ~ RAA(π) above 3 GeV/c: spectrum shape & fragmentation play an important role

B/D Energy Loss

Djordjevic et al. PRC 90 (2014) 034910

RAA =σ inel

pp

Ncoll

d 2NAA / dydpTd 2σ pp / dydpT

(GeV/c)TTransverse Momentum p0 1 2 3 4 5 6 7 8

AAR

00.20.40.60.8

11.21.41.61.8 Au+Au 200GeV, 0-10%

20140D2010/110D

π (0-12%)

STAR Preliminary

p+p uncert.


STAR: PRL 113 (2014) 142301 STAR: PLB 655 (2007) 2014

•  Strong suppression of D0 meson at high pT à substantial energy loss of charm quarks due to strong interactions with the medium

•  RAA(D0) ~ RAA(π) above 3 GeV/c: spectrum shape & fragmentation play an important role

)c (GeV/T

p1 2 3 4 5 6 7 8

AA

R

1

= 200 GeVNNsAu+Au 0-80%

STAR Preliminary

0.2

e→Be→D

e→BDUKE : e→DDUKE :

uncertaintye→B+DAAR

DUKE: PRC 92 (2015) 024907

•  RAA(Bàe) > RAA(Dàe) à consistent with mass hierarchy

B/D Energy Loss

Djordjevic et al. PRC 90 (2014) 034910

RAA =σ inel

pp

Ncoll

d 2NAA / dydpTd 2σ pp / dydpT


STAR: arXiv: 1701.06060

•  Large non-zero D0 v2 and v3 à strong collective behavior •  Both v2 and v3 follow the empirical mT scaling as light hadrons à

charm quarks may have acquired similar flow as light quarks

D0 Anisotropic Flow

) 2 (GeV/cq) / n0 - mT

(m0 0.5 1 1.5 2 2.5

q /

n2

Anis

otro

py P

aram

eter

, v

0

0.05

0.1

0.150D-Ξ

Λ

SK

STAR Au+Au @ 200 GeV10-40%

b)

)2)/NCQ (GeV/c0-mT

(m

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

3/2

/NC

Q3v

0.01−

0

0.01

0.02

0.03

0.04

0.05

0.06

STAR Preliminary

Au+Au 200 GeV 0-80%0D

p+K

+πφΛ

v2 v3


Compare D0 v2 with Models

SUBATECH: pQCD + hard thermal loop P. B. Gossiaux, J. Aichelin, T. Gousset, and V. Guiho, Strangeness in quark matter TAMU: T-matrix, non-perturbative, internal energy potential M. He, R. J. Fries, and R. Rapp, PRC86, 014903 (2012) Duke: free constant Ds, fit to LHC high pT RAA S. Cao, G.-Y. Qin, and S. A. Bass, PRC88, 044907 (2013) hydro: A 3D viscous hydrodynamic model L.-G. Pang, Y. Hatta, X.-N. Wang, and B.-W. Xiao,PRD91, 074027 (2015) PHSD: Parton-Hadron-String Dynamics, a transport model H. Berrehrah et al. PRC90 (2014) 051901 LBT: A Linearized Boltzmann Transport model S. Cao, T. Luo, G.-Y. Qin, and X.-N. Wang, PRC94, 014909 (2016)

(GeV/c)T

p0 1 2 3 4 5 6 7

2An

isot

ropy

Par

amet

er, v

0

0.1

0.2

0STAR DSUBATECHTAMU c-quark diff.TAMU no c-quark diff.

=7sTDπDuke - 2LBTPHSD3D viscous hydro

STAR Au+Au @ 200 GeV0-80%

•  3D hydro model: agrees with data quite well à fully thermalized •  Dynamic models are also consistent with data •  Charm quark diffusion is clearly needed •  Diffusion coefficient: Ds×2πT ~ 2-12 within Tc-2Tc

STAR: arXiv: 1701.06060

(GeV/c)T

p0 1 2 3 4 5 6 7 8

0/D sD

0

0.2

0.4

0.6

0.8

1Au+Au @ 200 GeVSTAR Preliminary

0-10%10-40%ee/pp/ep averagePYTHIA(ver. 6.4)TAMU(b=7.24fm)


ee/pp/ep average: M. Lisovyi, et al. EPJ C 76 (2016) 397 TAMU: H. Min et al. PRL 110 (2013) 112301

•  Ds/D0: larger than fragmentation baseline and PYTHIA à coalescence •  TAMU model (10-40%) under-predicts the enhancement around 3 GeV/c

–  For TAMU model, even harder to get high-pT enhancement with coalescence

Charm-strange Hadron Enhancement

(GeV/c)T

p0 1 2 3 4 5 6 7 8

0/D sD

0

0.2

0.4

0.6

0.8


0-10%10-40%ee/pp/ep averagePYTHIA(ver. 6.4)TAMU(b=7.24fm)


ee/pp/ep average: M. Lisovyi, et al. EPJ C 76 (2016) 397 TAMU: H. Min et al. PRL 110 (2013) 112301

•  Ds/D0: larger than fragmentation baseline and PYTHIA à coalescence •  TAMU model (10-40%) under-predicts the enhancement around 3 GeV/c

–  For TAMU model, even harder to get high-pT enhancement with coalescence

[GeV/c]T

p0 1 2 3 4 5 6 7 8

Rat

io

0

0.2

0.4

0.6

0.8


, 0-10%0/D+sD

, 10-40%0/D+sD

, 10-40%π/sK

STAR: PRL 108 (2012) 72301 STAR: PRL 97 (2006) 152301

•  Charm vs. light flavor: similar enhancement above 3.5 GeV/c, but smaller within 2.5-3.5 GeV/c

Charm-strange Hadron Enhancement


Λc in Heavy-ion Collisions

)2 (GeV/cπpKM2.1 2.2 2.3 2.4 2.5

)2C

ount

s/(1

0 M

eV/c

20

40

60

80

100

120

-π+Kp + +π-pKwrong-sign

Au+Au @ 200GeV 10-60%

<6.0 GeV/cT

3.0<p

STAR Preliminary

21±) = 108 cΛ#(

•  First ever Λc signal reconstructed in heavy-ion collisions •  5.4σ significance

(GeV/c)T

Transverse Momentum p

0 1 2 3 4 5 6

Bary

on-to

-Mes

on R

atio

s

1−10

1

)-π++π()p(p+

60-80%

0-12%

(GeV/c)T


0 1 2 3 4 5 6

2An

isot

ropy

Par

amet

er v

1−10

1

S02K)Λ+Λ(

60-80%

0-5%

(GeV/c)T


0 1 2 3 4 5 6

2An

isot

ropy

Par

amet

er v

1−10

1

)0D+0(D

)cΛ+cΛ(

10-60%

PYTHIA

/D)cΛGreco (

Ko: three-quark

0-5%

Ko: di-quark

SHM

STAR Preliminary

Au+Au @ 200GeVBa

ryon

/Mes

on R

atio

s

Transverse Momentum (GeV/c)


Ko: Y. O

h, et al. PRC 79 (2009) 044905

Greco: S. G

hosh, et al. PRD 90 (2014) 054018

SHM

: Y. O

h, et al. PRC 79 (2009) 044905

I. Kuznetsova and J. Rafelski,, EPJ C

51 (2007) 113 A. Andronic,, et al. PLB

659 (2008) 149

•  Enhancement of Λc/D0 ratio relative to PYTHIA prediction Ø  STAR: 1.3 ± 0.3 (stat) ± 0.4 (sys); PYTHIA: 0.1-0.15

•  Ko model (0-5%) including coalescence and thermalized charm quark is consistent with data

•  Magnitude of the enhancement is similar to that for light hadrons

Λc Enhancement in Heavy-ion Collisions

partN0 50 100 150 200 250 300 350

pA,A

A R

ψJ/

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2, |y| < 0.5-µ+µ→ψSTAR J/

> 0 GeV/cT

Au+Au @ 200 GeV, p > 5 GeV/c

TAu+Au @ 200 GeV, p

> 1 GeV/cT

p+Au @ 200 GeV, p > 5 GeV/c

Tp+Au @ 200 GeV, p

uncertaintycollN

STAR preliminary

J/ψ RAA vs. Centrality

•  Central collisions: significant suppression for pT > 0 GeV/c and pT > 5 GeV/c à interplay of dissociation, regeneration, formation time effect, etc.

•  Peripheral collisions: RAA of J/ψ for pT > 0 GeV/c is less than 1à consistent with cold nuclear matter (CNM) effects


Au Au Au Au

partN0 50 100 150 200 250 300 350

AA

Rψ

J/

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

uncertaintycollSTAR N

STAR preliminary > 0 GeV/cψT,J/

p, |y| < 0.5-µ+µ→ψ = 200 GeV, J/NNsSTAR: Au+Au,

, |y| < 0.35-e+e→ψ = 200 GeV, J/NNsPHENIX: Au+Au, , |y| < 0.8-e+e→ψ = 2.76 TeV, J/NNsALICE: Pb+Pb,


ALICE : PLB 734 (2014) 314 PHENIX : PRL 98 (2007) 232301 pT

> 0 GeV/c

•  pT > 0 GeV/c: more suppressed at RHIC in central events à smaller regeneration contribution due to lower charm cross-section

J/ψ RAA: RHIC vs. LHC

partN0 50 100 150 200 250 300 350

AA

Rψ

J/

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2


STAR preliminary > 0 GeV/cψT,J/

p, |y| < 0.5-µ+µ→ψ = 200 GeV, J/NNsSTAR: Au+Au,

, |y| < 0.35-e+e→ψ = 200 GeV, J/NNsPHENIX: Au+Au, , |y| < 0.8-e+e→ψ = 2.76 TeV, J/NNsALICE: Pb+Pb,


ALICE : PLB 734 (2014) 314 PHENIX : PRL 98 (2007) 232301 pT

> 0 GeV/c

•  pT > 0 GeV/c: more suppressed at RHIC in central events à smaller regeneration contribution due to lower charm cross-section

CMS: JHEP 05 (2012) 063

•  pT > 5 GeV/c: less suppressed at RHIC à smaller dissociation rate due to lower temperature

J/ψ RAA: RHIC vs. LHC pT

> 5 GeV/c

partN0 50 100 150 200 250 300 350

AA

Rψ

J/

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2


-µ+µ→ψJ/ > 5 GeV/c

T = 200 GeV, |y| < 0.5, pNNsSTAR: Au+Au,

> 6.5 GeV/cT

= 2.76 TeV, |y| < 2.4, pNNsCMS: Pb+Pb,

STAR preliminary

ϒ Suppression at RHIC

•  ϒ(1S) is suppressed –  Indication of more suppression with increasing centrality –  Is direct ϒ(1S) suppressed?


partN0 100 200 300 400

pA, A

AR

0

0.2

0.4

0.6

0.8

1

1.2

1.4 0-60%30-60% 10-30% 0-10%

(1S): Au+Au@200 GeV |y|<0.5ϒ(1S+2S+3S): p+Au@200 GeV |y|<0.5ϒ


STAR Preliminary

ϒ(1S) RAA

ϒ Suppression at RHIC

•  ϒ(1S) is suppressed –  Indication of more suppression with increasing centrality –  Is direct ϒ(1S) suppressed?


partN0 100 200 300 400

pA, A

AR

0

0.2

0.4

0.6

0.8

1

1.2

1.4 0-60%30-60% 10-30% 0-10%

(1S): Au+Au@200 GeV |y|<0.5ϒ(1S+2S+3S): p+Au@200 GeV |y|<0.5ϒ


STAR Preliminary

partN0 100 200 300 400

(1S)

ϒ(2

S+3S

)/ϒ

0

0.1

0.2

0.3

0.4

0.5

0.6 0-60%30-60% 10-30% 0-10%

STAR Au+Au@200 GeV |y|<0.5pp world-wide average


STAR Preliminary

World-wide p+p: W. Zha, et. al, PRC 88 (2013) 067901

•  Central: ϒ(2S+3S) is more suppressed à sequential melting

ϒ(1S) RAA ϒ(2S+3S)/ϒ(1S)

ϒ: RHIC vs. LHC

•  ϒ(1S) suppression: similar at RHIC and LHC


partN0 100 200 300 400

pA, A

AR

0

0.2

0.4

0.6

0.8

1

1.2

1.4 0-60%30-60% 10-30% 0-10%

(1S): STAR Au+Au@200 GeV |y|<0.5ϒ(1S): CMS [email protected] TeV |y|<2.4ϒ(1S+2S+3S): STAR p+Au@200 GeV |y|<0.5ϒ


STAR Preliminary

CMS: arXiv:1611.01510 ϒ(1S) RAA

partN0 100 200 300 400

pA, A

AR

0

0.2

0.4

0.6

0.8

1

1.2

1.4 0-60%30-60% 10-30% 0-10%



STAR Preliminary

ϒ: RHIC vs. LHC



CMS: arXiv:1611.01510

•  Ralf model: seems consistent with ϒ(1S) suppression by including CNM and regeneration –  However, under-predicts the ϒ(2S) suppression at the LHC

R. Rapp (QM2017) ϒ(1S) RAA

partN0 100 200 300 400

pA, A

AR

0

0.2

0.4

0.6

0.8

1

1.2

1.4 0-60%30-60% 10-30% 0-10%



STAR Preliminary

ϒ: RHIC vs. LHC



CMS: arXiv:1611.01510

partN0 100 200 300 400

AA

R

0

0.2

0.4

0.6

0.8

1

1.2

1.4 0-60%30-60% 10-30% 0-10%

95% C. L.

(2S+3S): STAR Au+Au@200 GeV |y|<0.5ϒ(2S): CMS [email protected] TeV |y|<2.4ϒ(3S): CMS [email protected] TeV |y|<2.4ϒ

uncertaintycollSTAR NSTAR Preliminary

•  ϒ(2S+3S): hint of less suppression at RHIC than at the LHC

ϒ(1S) RAA ϒ(2S+3S) RAA

Summary & Outlook


•  Upgrades of HFT and MTD greatly enhance STAR’s capabilities of measuring both open and hidden heavy flavor production.

Summary & Outlook



•  Open heavy flavor –  Mass hierarchy of energy loss à strong interaction with medium –  Collective behavior of charm quarks à suggests thermal equilibrium –  Charm quarks seem to also participate in coalescence hadronization

Summary & Outlook




•  Quarkonium –  Strong suppression of J/ψ at high-pT in central collisions à dissociation –  ϒ(2S+3S) is more suppressed than ϒ(1S) in central collisions à sequential

melting –  ϒ(1S) RAA: RHIC ≈ LHC. Model including CNM, dissociation, regeneration

seems consistent with data

Summary & Outlook




•  Quarkonium –  Strong suppression of J/ψ at high-pT in central collisions à dissociation –  ϒ(2S+3S) is more suppressed than ϒ(1S) in central collisions à sequential

melting –  ϒ(1S) RAA: RHIC ≈ LHC. Model including CNM, dissociation, regeneration

seems consistent with data •  Outlook: 2016 Au+Au data

–  A factor of 2 (minimum-bias) and 5 (high-pT electrons) for HFT –  Equivalent statistics for ϒ measurement

Backup

ϒ RAA vs. pT

•  ϒ(1S): no obvious dependence on pT; similar to CMS

•  ϒ(2S+3S): hint of less suppression at high pT


ϒ(1S) ϒ(2S+3S)

(GeV/c)T

p0 2 4 6 8 10

AA

R

0

0.2

0.4

0.6

0.8

1

1.2STAR Au+Au@200 GeV (0-60%)

-µ+µ→ϒ(1S) |y|<0.5 ϒCMS [email protected] TeV (0-100%)

(1S) |y|<2.4 ϒ

STAR Preliminary

(GeV/c)T

p0 2 4 6 8 10

AA

R

0

0.2

0.4

0.6

0.8

1

1.2STAR Au+Au@200 GeV (0-60%)

-µ+µ→ϒ(2S+3S) |y|<0.5 ϒCMS [email protected] TeV (0-100%)

(2S) |y|<2.4ϒ

90% C. L.

STAR Preliminary

Overview of recent heavy-flavor results from STARmoriond.in2p3.fr/QCD/2017/FridayMorning/Ma.pdf ·...

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Transcript of Overview of recent heavy-flavor results from STARmoriond.in2p3.fr/QCD/2017/FridayMorning/Ma.pdf ·...