Open Heavy Flavor Results from STAR1 Open Heavy Flavor Results from STAR Guannan XIE (for the STAR...
Transcript of Open Heavy Flavor Results from STAR1 Open Heavy Flavor Results from STAR Guannan XIE (for the STAR...
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
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL) 3
• 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
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL) 4
Time Projection Chamber: Tracking, PID (dE/dx),|η|<1, 2π
Time Of Flight detector: PID (1/β), |η|<0.9, 2π
Heavy Flavor Tracker
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL) 5
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%
Au+Au @ 200 GeV STAR Preliminary
(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
Au+Au @ 200 GeV STAR Preliminary
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
Transverse Momentum p
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
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
Transverse Momentum p
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
Transverse Momentum p
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
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
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
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
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
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
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)
21 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
• 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
22 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
• 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
23 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
(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
24 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
D0 in AuAu (2010/2011 TPC Analysis) - I Erratum: PRL 113 (2014) 142301
25 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
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)
26 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
(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
Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
B Study from Non-prompt J/ψ & D0 & e
28 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
Note: RAA references (data vs. theory) are different for different channels
29 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
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
30 Guannan Xie 2018 RHIC & AGS Annual Users' Meeting (BNL)
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