Open Heavy Flavor Results from STAR1 Open Heavy Flavor Results from STAR Guannan XIE （for the STAR Collaboration） University of Illinois at Chicago Guannan Xie 2018 RHIC & AGS

1

Open Heavy Flavor Results from STAR

Guannan XIE （for the STAR Collaboration） University of Illinois at Chicago

2018 RHIC & AGS Annual Users' Meeting (BNL) Guannan Xie

Introduction

Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL) 2

Heavy quarks: mc/b >> ΛQCD, TQGP(RHIC) •  Produced early in heavy-ion collisions through hard scatterings •  Experience the whole evolution of the system à good probe of medium properties, e.g. transport parameters

arXiv: 1502.02730

Contents


•  In medium energy loss D0 RAA, RCP •  Hadronization Λc, Ds •  Charm conservation Total charm cross-section •  Possible medium modification

of spectral function D*+/-

•  Mass dependence of energy loss B→(J/ψ, D0, e)

•  Probe the longitudinal profile and electromagnetic field

D0 v1 •  Transport coefficients D0 v2

STAR Detector


Time Projection Chamber: Tracking, PID (dE/dx),|η|<1, 2π

Time Of Flight detector: PID (1/β), |η|<0.9, 2π

Heavy Flavor Tracker


Heavy Flavor Tracker

HFT: •  Silicon Strip Detector: r ~22 cm •  Intermediate Silicon Tracker: r ~14 cm •  PIXEL detector: r ~2.8 & 8 cm, MAPS, 20.7x20.7 µm2, 0.4%X0(2016) thick, air-cooled

DCAXY Resolution

D0 pT Spectra

Guannan Xie 6

(GeV/c)T

p0 2 4 6 8 10

-2dy

) (G

eV/c

)T

dp Tpπ2ev

N/(N

2 d

7−10

5−10

3−10

1−10

10

20142010/112014(qm15)

Au+Au @ 200 GeVSTAR Preliminary

20)×0-10% (5)×10-40% (

2)×40-80% (

2018 RHIC & AGS Annual Users' Meeting (BNL)

]-2

dy) [

(GeV

/c)

Tdp Tpπ2

evN

/(N2 d

6−10

3−10

1

10

2014

2010/11

(a)(a)(a)

Levy Fit

= 200 GeVNNsAu+Au

10)×0-10% (

2)×10-40% (1)×40-80% (

0.5

1

1.5

0-10%(b)

0.5

1

1.5

10-40%(c)

(GeV/c)T

p0 5 10

0.51

1.5

40-80%(d)

Rat

io

STAR Preliminary

•  Precise measurements of D0 spectra extended to low pT and non-central collisions with HFT from 2014 data

•  Results consistent with the re-analyzed 2010/11 TPC analysis

D0 RAA

0.5

1

1.5 Run14

Run10/11

(a) 0-10%

= 200 GeVNNsAu+Au

0.5

1

1.5(b) 10-40%

(GeV/c)T

p0 2 4 6 8

0.5

1

1.5(c) 40-80%

AAR

STAR Preliminary

7

•  RAA < 1 in the 0-10% centrality interval for all pT •  Suppression at high pT increases towards more central collisions •  Similar to D-mesons at LHC and high-pT pions at RHIC

(GeV/c)T

p0 2 4 6 8 10

0.5

1

1.5

0-10% STAR0 D

D 0-10% ALICE

LBT

Duke

= 200 GeVNNsAu+Au

(a)

(GeV/c)T

p0 2 4 6 8 10

0.5

1 0-12% STAR±π

0-5% ALICE±h

0-12% STAR±π

0-5% ALICE±h

(b)

AAR

STAR Preliminary STAR:Phys. Lett. B 655 (2007) 104 ALIC

E: JHEP 03 (2016) 081

LBT: Phys. Rev. C94, 014909 (2016)+

private comm.

DU

KE: PRC

92 (2015) 024907+private com

m.

D0 RCP and D0/D0 Ratio

(GeV/c)T

p0 2 4 6 8

0.5

1

1.5

0-10%

Au+Au @ 200 GeV STAR Preliminary

, |y| < 1.00 / D0

D

0.021±1.104 Fit :

(a)

(GeV/c)T

p0 2 4 6 8

0.5

1

1.5

10-20% 20-40% , 0.019±1.071 Fit : 0.015±1.060

(b)

(GeV/c)T

p0 2 4 6 8

0.5

1

1.5

40-60% 60-80% , 0.022±Fit : 1.073 0.039± 0.943

(c)

)0/D0 D

Rat

io (

8

(GeV/c)T

p0 2 4 6 8

0.5

1

1.5 , 0-12%π

, 0-5%0sK

, φ 0 D

LBT Duke

(a) 0-10%


(GeV/c)T

p0 2 4 6 8

0.5

1

(b) 10-20%

(GeV/c)T

p0 2 4 6 8

0.5

1

(c) 20-40%

(X/4

0-60

%)

cpR

•  Significant suppression at high pT . •  Reasonable agreement with theoretical calculations •  D0/D0 ratio is larger than 1.

一

一

D0 Cross-section and Blast Wave Fit

50

100 2014

2010/11

> 0 GeV/cT

p


p+p

(a)

partN0 100 200 300

0

0.2

0.4

0.6

0.8 > 4 GeV/c

Tp

(b)

Uncer.partN

b)µ (

y=0

/dy|

NN

σd

> (c)β<0 0.1 0.2 0.3 0.4 0.5 0.6

T (G

eV)

0

0.1

0.2

0.3

0.4Au+Au @ 200 GeV

STAR Preliminary

0D-Ξ,φ

,K,pπ

60-80%

0-10%

60-80% 0-5%

70-80%0-5%

9

•  Total D0 cross-section is nearly independent of centrality, and smaller than in p+p. However, for pT > 4 GeV/c it decreases with centrality.

•  Blast Wave fits (pT < 5 GeV/c) : suggests earlier freeze-out of D0

Λc and Heavy Quark Hadronization

Guannan Xie 10

•  Strong enhancement of Λc/D0 ratio seen in Au+Au collisions.

•  Enhancement predicted from coalescence hadronization.

•  Enhancements relative to PYTHIA also seen in p+p and p+Pb collisions at LHC.

(GeV/c)T

Transverse Momentum p

0 1 2 3 4 5 6

Bary

on-to

-Mes

on R

atio

s

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 @ 200 GeV

0 /

Dc

Λ

(GeV/c)T


QM17

Ko: PRC 79 (2009) 044905. Greco: PRD 90 (2014) 054018 SHM: PRC 79 (2009) 044905. ALICE: arXiv:1712.09581

Λc/D0 in A+A pT and centrality dependence?

Λc Reconstruction

Guannan Xie 11

•  More than 50% improvement in signal significance with TMVA BDT •  Also new data from 2016 à Effectively 4x more data

2014 (Rectangular) QM17 2014+2016 (BDT)

2018 RHIC & AGS Annual Users' Meeting (BNL)

Λc/D0 : pT Dependence

Guannan Xie 12

•  Significant enhancement of Λc/D0 compared to PYTHIA/fragmentation baseline

•  The Λc/D0 ratio is comparable with light flavor baryon-to-meson ratios •  Consistent with charm quark hadronization via coalescence

-- higher than model predictions, particularly at higher pT

(GeV/c)T


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

isotro

py P

aram

eter

v

1−10

1

S02K)Λ+Λ(

60-80%

0-5%

(GeV/c)T


0 1 2 3 4 5 6

2An

isotro

py P

aram

eter

v

1−10

1

)0D+0(D

)cΛ+cΛ(

Ko: three-quark (0-5%)

Ko: di-quark (0-5%)

Greco (0-20%)

PYTHIA

SHM

STAR Preliminary

Au+Au @ 200GeV

10-80%

Bary

on/M

eson

Rat

ios

Transverse Momentum (GeV/c)

Ko: PRC

79 (2009) 044905 Greco: Eur.Phys.J.C

(2018) 78:348 SH

M: PRC

79 (2009) 044905 ALICE: arXiv:1712.09581

Λc/D0 : Centrality Dependence

Guannan Xie 13

•  Λc/D0 ratio increases from peripheral to central collisions, indicative of hot medium effects

•  Ratio for peripheral Au+Au comparable with p+p value at 7 TeV

ALICE: arXiv:1712.09581

Ds/D0 Enhancement

14

•  Strong Ds/D0 enhancement observed in central A+A collisions w.r.t fragmentation baseline

- Strangeness enhancement and coalescence hadronization •  Enhancement is larger than model predictions, particularly at higher pT

SHM

ep/pp/ep avg: M Lisovyi, et. al. EPJ C

76, 397 (2016) TAM

U: H

. Min et al. PRL 110, 112301 (2013)

SHM

: A. Andronic et al., PLB 571 (2003) 36

Guannan Xie

Total Charm Cross-section

15

•  Total charm cross-section is estimated from the various charm hadron measurements

Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)

•  Total charm cross-section is consistent with p+p value within uncertainties, but redistributed

D0 yields are measured down to zero pT For D+/- and Ds, levy fits to measured spectra are used for extrapolation. For Λc, three model fits to data are used and differences are included in systematics

-- -- --

D*+/D0 Ratio in Au+Au Collisions

16

(GeV)T

p2 4 6 8 10

0/D

*+D

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6Au+Au @ 200GeV

0~10%ALICE, 0~10% Pb+Pb @ 5.02TeVPYTHIA8 (STAR-HF Tune)

STAR Preliminary

>part<N50 100 150 200 250 300 350

Rat

io

00.10.20.30.40.50.60.70.80.9

1 > 0 GeV/c)

T (p- K*/K

Au+Au @ 62.4 GeVCu+Cu @ 62.4 GeVAu+Au @ 200 GeVCu+Cu @ 200 GeV

< 10 GeV/c)T

(2 < p0/D+ D*Au+Au @ 200 GeVPYTHIA8 (STAR-HF Tune)

STAR Preliminary


K*/K, Phys. Rev. C (2011)84.3: 034909. ALICE, Collaboration. arXiv:1804.09083.

•  Possible hot medium effects : - D*+ life time could become shorter in hot medium - Re-scattering can lead to a yield loss •  D*+/D0 ratio in Au+Au collisions at 200 GeV is consistent with

PYTHIA and with ALICE data at higher pT. •  Ratio of the integrated yields shows no strong centrality dependence

Non-prompt D0

17

•  Strong interaction of charm with the medium. How about bottom? •  RAA of non-prompt D0 extracted from the measured non-prompt fraction •  Improved signal significance for non-prompt D0 fraction using BDT.

New result down to low pT with 2014+2016 data on the way


B Study from Non-prompt J/ψ & D0 & e

18

•  Strong suppression for B→ J/ψ and D0 at high pT. •  Indication of less suppression for B→e than D→e (~2 𝜎): consistent

with ΔEc > ΔEb •  Measurements with improved precision are on the way


Note: RAA references (data vs. theory) are different for these comparisons. The decay kinematics needs to be unfolded for different channels.

D0 Directed Flow (v1)

19 Rapidity (y)0.5− 0 0.5

) 1D

irect

ed fl

ow (v

0.1−

0

0.1c)u (0D

)c (u0Ds)u + s (u- + K+K

=200 GeV, 10-80%NNsAu+Au > 1.5 GeV/c

Tp

STAR Preliminary

points shifted along x-axis by 0.040D

-slope from linear fit1v 0.021(syst.)± 0.030 (stat.) ±/dy = -0.102 1 dv0D 0.023 (syst.)± 0.030 (stat.) ±/dy = -0.061 1 dv0D

0.0002(syst.)± 0.0001(stat.) ±/dy = -0.0030 1Kaons dv

2014+2016

一

一

Guannan Xie

一 •  Charm and anti-charm quarks can be deflected differently by the initial

EM field → difference between D0 and D0 v1 sensitive to EM field •  Charm quarks interact with bulk medium → D0 v1 sensitive to the

initial tilt of the source (bulk) •  First observation of non-zero (negative) D0(D0) v1 slope •  D0(D0) v1-slope much larger than that of kaons

D0 Elliptic Flow (v2)

20 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)

•  Published D0 v2 from data taken during 2014 •  Clear mass ordering for pT < 2 GeV/c •  Follows NCQ-scaling in mid-central (10 - 40%) collisions

Phys Rev. Lett. 118, 212301 (2017)

D0 Elliptic Flow (v2)


•  D0 v2 measurement extended to 0-10% centrality with combined data from 2014 and 2016 runs

•  NCQ-scaling test with improved precision •  Charm quarks gain significant flow! 2014+2016

Summary


•  Strong modification of charm hadron spectra and hadrochemistry in A+A collisions. (D0 RAA & Rcp, Ds/D0, Λc/D0, D0 v2, D0 v1).

-- total charm quark cross-section conserved -- substantial energy loss & coalescence hadronization -- gain significant flow & may have achieved thermal equilibrium in the medium (D0 v2) -- first observation of non-zero directed flow (v1) for D0.

•  Strong energy loss at high pT for B→ J/ψ, and B→D0 measurements. Indication of less energy loss for bottom (B→e), and measurement with better precision on the way.

Summary II – Charm / Bottom


(GeV/c)T

p0 2 4 6 8

AAR

0.5

1 0-10% 0 D

0-12% STAR±π

= 200 GeVNNsAu+Au

0-10% 0 D

0-12% STAR±π

STAR Preliminary STAR Preliminary

RAA (D0) ~ RAA (π) - lose significant energy v2 (D0) ~ v2 (h) vs. mT - gain significant flow

Experimental : precision measurement of bottom Theoretical : converge on value of transport parameters

Next

Back up


D0 in AuAu (2010/2011 TPC Analysis) - I Erratum: PRL 113 (2014) 142301


1.  Two mistakes were discovered in calculating TOF related efficiency corrections - Hybrid PID: algorithm inconsistently implemented in data analysis vs. efficiency calculation

- a DCAxy cut efficiency was included in the correction two times 2. p+p measurement: no issue discovered, but the p+p D0 baseline used for RAA is updated

with latest knowledge of charm frag. ratios - considering the pT dependence of D*/D0 frag. ratio - latest world average of c->D0 and c->D* frag. ratios

(D0 at pT<2 GeV/c + D* at 2-6 GeV/c, PRD 86 (2012) 072012)


(GeV/c)T

p0 1 2 3 4 5 6 7 8

AAR

00.20.40.60.8

11.21.41.61.8

2STAR preliminary

= 200 GeVNNsAu+Au

Centrality 0-10%

2016±D

20140D 2016 Glob. Sys.±D

Glob. p+p uncert.

p+p uncert.

D+/- RAA

•  Similar suppression for D0 and D+/-

•  Spectra measurement was important for the total charm cross-section

D*+ Production in Au+Au Collisions

27

•  D*+ feeds down to D0 yields •  Hot medium effects : - D*+ life time could become shorter in hot medium - Re-scattering can lead to loss of yield

D*+ →D0 +π soft+

Phys. Rev. C (2018)97, 034918. Phys. Rev. C (2011)84, 034909


B Study from Non-prompt J/ψ & D0 & e


Note: RAA references (data vs. theory) are different for different channels


Directed flow (v1) due to EM fields

•  The moving spectators can produce enormously large electromagnetic field (eB ~ 1018 G at RHIC)

•  Due to early production of heavy quarks (τCQ ~ 0.1 fm/c) positive and negative charm quarks (CQs) can get deflected by the initial EM force

•  D0 and D0 v1 can offer insight into the early time EM fields


Directed flow (v1) due to hydro

Chatterjee, Bozek: Phys Rev Lett 120, 192301 (2018)

à (v1-slope)CQ >> (v1-slope)LQ CQs much more sensitive to the initial tilt than the charged hadrons

•  Heavy quarks are produced according to Ncoll density: symmetric in rapidity

•  At non-zero rapidity, CQs production points are shifted from the bulk

•  This can induce larger v1 in CQs than light flavors

•  Magnitude of CQ v1 depends on the drag parameter used in this model

Documents

Open Heavy Flavor Results from STAR1 Open Heavy Flavor Results from STAR Guannan XIE （for the STAR Collaboration） University of Illinois at Chicago Guannan Xie 2018 RHIC & AGS