[PPT] - Recent Heavy Flavor Results from PHENIX Kazuya Nagashima PowerPoint Presentation

SLIDE 1

Recent Heavy Flavor Results from PHENIX

Kazuya Nagashima (Hiroshima Univ. / RIKEN)

SLIDE 2

Au Au time z QGP ! b b B$ B%

Generation

τ0 = 1/2mc,b
pQCD-NLO

QGP dynamics

energy loss
flow and thermalization?

Hadronization

coalescence
fragment.

ü Introduction of Heavy Flavor Probe

K. Nagashima - QNP 2018 - Nov. 16, 2018

2

> produced in initial stage (τ0 = 1/2mc,b) > probe full time evolution > conserved HF number

Modification of phase space

dist. reflects QGP dynamics!

SLIDE 3

[GeV/c]

T

p 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

2

Azimuthal anisotoropy v 0.02 − 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

e → c+b

=200 GeV

NN

s

min. bias Au+Au,

Phys.Rev.Lett.98,172301

[GeV/c]

T

p 1 2 3 4 5 6 7 8 9

AA

Nuclear modification factor R 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2

e → c+b

=200 GeV

NN

s 0-10% central. Au+Au, Phys.Rev.Lett.98,172301

e → c+b

=200 GeV)

NN

s (dAu,

3

Strong suppression in Au+Au
Large CNM in d+Au
Quark mass dependence?
Large v2 of HF→e in Au+Au
v2 of HF→e in d+Au?
Quark mass dependence?
K. Nagashima - QNP 2018 - Nov. 16, 2018

Nuclear modification factor of HF→e Azimuthal anisotropy v2 of HF→e

ü Previous Heavy Flavor Measurement

SLIDE 4

4

K. Nagashima - QNP 2018 - Nov. 16, 2018

ü Previous heavy flavor measurement

[GeV/c]

T

p 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

2

Azimuthal anisotoropy v 0.02 − 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

e → c+b

=200 GeV

NN

s

min. bias Au+Au,

Phys.Rev.Lett.98,172301 [GeV/c]

T

p 1 2 3 4 5 6 7 8 9

e) → e, b → (c

AA

R

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2

e (Phys.Rev.C 84,044905) → c+b e → c e → b =200 GeV

NN

s 0-10% Au+Au, Data 2004+2014, |y|<0.35 p+p from e-h correlations Phys.Rev.Lett.105,202301

PH ENIX

preliminary

Strong suppression in Au+Au
Large CNM in d+Au
Quark mass dependence?
Large v2 of HF→e in Au+Au
v2 of HF→e in d+Au?
Quark mass dependence?

Nuclear modification factor of HF→e Azimuthal anisotropy v2 of HF→e

SLIDE 5

ü Heavy Flavor Measurement at PHENIX

5

[Mid-rapidity] electrons at Central arm (with RICH and EMCal) φ = π, |η| = 0.35 [Forward-rapidity] muons at Muon arm absorber: 7.2 Xint φ = 2π, 1.2 < |η| < 2.2 [Collision systems] p+p, p+Al, p+Au, d+Au,

3He+Au, AuAu, CuAu

[Collision energies] 20 ~ 200 ~ 510 GeV/c e- e+ μ- μ+

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 6

ü Silicon Vertex Detector @ PHENIX

6

[VTX]

2 pixel layers + 2 strip layers

(σφ = 14.4 μm) (σφ = 23 μm) [FVTX]

4 strip layers (σφ = 75 μm)

Displaced vertex analysis

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 7

7

Heavy Flavor Results in Small System (p+p) → production mechanism and baseline

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 8

1 2 3 4 5 6 7 8 9 ]

2

dy) [mb (GeV/c)

T

/dp σ

2

) d

T

p π (1/2

10 −

10

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10 = 200 GeV

NN

s p+p at | < 0.35 η | e → e + b → c e → b e → c Inclusive HF Electrons [PRC 84, 044905] [GeV/c]

T

Electron p 1 2 3 4 5 6 7 8 9 e) → Data / (c+b 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4

PH ENIX

preliminary

ü Invariant Yield of c→e and b→e in p+p

8 Invariant yield of c→e and b→e DCAT distribution

Displaced vertex analysis for single electrons at mid-rapidity
Simultaneous fit to DCAT distribution and invariant yield
Unfold x-section of c, b hadrons, refold invariant yield of c, b→e
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 9

ü Production Mechanism of ! ̅ ! and # ̅ #

9

[c% c production] > Flavor excitation dominates > Wider distribution than b% b → NLO process is higher [b% b production] > Pair creation dominates

K. Nagashima - QNP 2018 - Nov. 16, 2018

Pair angle distribution is sensitive to production mechanism of HF

Fit with 3 templates (from PYTHIA) Pair creation Flavor excitation Gluon splitting

SLIDE 10

10

Heavy Flavor Results in Small System (d+Au) → Flow in Small System

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 11

ü Single muon measurement in d+Au

Single muons are measured at

both Au-direction and d-direction.

0-20% high-multiplicity events

are used for !"

#$ analysis.

Main background sources:

+ hadron decay μ + punch thorough hadrons + J/ψ decay μ

!"

#$ is calculated by

!"

#$ =

1 '#$ (!"

)*+,. − 1 − '/0 ×!" 23)

11

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 12

ü Heavy Flavor Anisotropic Flow in d+Au

12

0.5 1 1.5 2 2.5

[GeV/c]

T

p

0.05 0.1 0.15 0.2 0.25 0.3

}

< -3.1 η

3.9 <

{EP

2

v

from open heavy flavor decays

µ

=200 GeV

NN

s 0-20% d+Au

< -1.4 η

2.0 <

= 1.9%

Global

Sys 0.5 1 1.5 2 2.5

[GeV/c]

T

p

0.05 0.1 0.15 0.2 0.25 0.3

from open heavy flavor decays

µ

=200 GeV

NN

s 0-20% d+Au

< 2.0 η 1.4 < = 1.9%

Global

Sys

PH ENIX

preliminary

K. Nagashima - QNP 2018 - Nov. 16, 2018

Au-direction d-direction

Measured non-zero !"

#$%→' in small collision system.

heavy flavor flows in small collision system?

SLIDE 13

ü Heavy Flavor Anisotropic Flow in d+Au

13

K. Nagashima - QNP 2018 - Nov. 16, 2018

0.5 1 1.5 2 2.5

[GeV/c]

T

p

0.05 0.1 0.15 0.2 0.25 0.3

}

< -3.1 η

3.9 <

{EP

2

v

from open heavy flavor decays

µ

Charged hadrons

=200 GeV

NN

s 0-20% d+Au

< -1.4 η

2.0 <

= 1.9%

Global

Sys 0.5 1 1.5 2 2.5

[GeV/c]

T

p

0.05 0.1 0.15 0.2 0.25 0.3

from open heavy flavor decays

µ

Charged hadrons

=200 GeV

NN

s 0-20% d+Au

< 2.0 η 1.4 < = 1.9%

Global

Sys

PH ENIX

preliminary

Au-direction d-direction

Measured non-zero !"

#$%→' in small collision system.

heavy flavor flows in small collision system?
similar order of magnitude, !"

#$%→' ~ !" ( (not direct comparison)

→ One of the key to understand flow in small system

SLIDE 14

14

Heavy Flavor Results in Large System (Au+Au) → HF dynamics in QGP

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 15

counts 1 10

2

10

3

10

4

10

Data Background =200 GeV

NN

s Au+Au,

min. bias, |y|<0.35

Data 2014 [2.00-2.20 GeV/c] b/(c+b)=0.31

[cm]

T

DCA 0.1 − 0.05 − 0.05 0.1

stat

σ (Data - Re-fold)/

2 − 2

ü Invariant Yield of c→e and b→e in Au+Au

15

DCAT distribution

]

2

[(GeV/c) y d

T

p N/d

2

)d

T

p π (1/2

10 −

10

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10 =200 GeV

NN

s Au+Au, minimum bias, |y|<0.35

e (Data) → c+b

[GeV/c]

T e

p 1 2 3 4 5 6 7 8 9 Data/Re-fold 1 2

Invariant yield

Displaced vertex analysis for single electrons at mid-rapidity
Simultaneous fit to DCAT distribution and invariant yield
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 16

ü Invariant Yield of c→e and b→e in Au+Au

16

counts 1 10

2

10

3

10

4

10

Data Re-fold Charm Bottom Background =200 GeV

NN

s Au+Au,

min. bias, |y|<0.35

Data 2014 [2.00-2.20 GeV/c] b/(c+b)=0.31

[cm]

T

DCA 0.1 − 0.05 − 0.05 0.1

stat

σ (Data - Re-fold)/

2 − 2 ]

2

[(GeV/c) y d

T

p N/d

2

)d

T

p π (1/2

10 −

10

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10 =200 GeV

NN

s Au+Au, minimum bias, |y|<0.35

e (Data) → c+b e (Re-fold) → c+b e (Unfolded) → c e (Unfolded) → b

[GeV/c]

T e

p 1 2 3 4 5 6 7 8 9 Data/Re-fold 1 2

DCAT distribution Invariant yield

Displaced vertex analysis for single electrons at mid-rapidity
Simultaneous fit to DCAT distribution and invariant yield
Unfold yield of c, b hadrons, refold invariant yield of c, b→e
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 17

ü Extraction of v2 for c→e and b→e

17

counts 1 10

2

10

3

10

4

10

Data Re-fold Charm Bottom Background =200 GeV

NN

s Au+Au,

min. bias, |y|<0.35

Data 2014 [2.00-2.20 GeV/c] b/(c+b)=0.31

[cm]

T

DCA 0.1 − 0.05 − 0.05 0.1

stat

σ (Data - Re-fold)/

2 − 2

DCAT distribution

[GeV/c]

T

p

1 1.5 2 2.5 3 3.5 4 4.5 5 HF 2

e v

0.05

0.05 0.1 0.15 0.2 0.25 |DCA|<0.02 charm enriched 0.03<|DCA|<0.1 bottom enriched

=200GeV

NN

s

Min. bias Au+Au

from open heavy flavor

2

e v

PH ENIX

preliminary

Extraction of c→e and b→e v2

!"

# $%#& = ( #×!" # + (+×!" + + (+,×!" +,

!"

+ $%#& = ( #×!" # + (+×!" + + (+,×!" +,

>> Solve simultaneous equations! Divide DCA distribution to c rich region: |DCA| < 200μm b rich region: 300 < |DCA| < 1000μm

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 18

ü Anisotropic Flow of c→e and b→e in Au+Au

18

[GeV/c]

T

p

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

c 2

e v

0.05

0.05 0.1 0.15 0.2 0.25

=200GeV

NN

s

Min. bias Au+Au

from charm decay

±

e PHENIX PRC92.034913

±

h

PH ENIX

preliminary

[GeV/c]

T

p

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

b 2

e v

0.05

0.05 0.1 0.15 0.2 0.25

=200GeV

NN

s

Min. bias Au+Au

from bottom decay

±

e PHENIX PRC92.034913

±

h

PH ENIX

preliminary

v2 of c→e v2 of b→e

K. Nagashima - QNP 2018 - Nov. 16, 2018

First measurement at RHIC

PHENIX VTX analysis allow low pT v2 measurement
c-quark is strongly coupled in QGP, 0 < !"

#→% < !" &

> need unfolding and QCN scaling to direct comparison...

b-quark flow is likely less than c-quark flow in QGP

→ b-quark slightly flows? 0 < !"

'→% < !" #→%

SLIDE 19

[GeV/c]

T

p

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

c 2

e v

0.05

0.05 0.1 0.15 0.2 0.25

=200GeV

NN

s

Min. bias Au+Au

from charm decay

±

e PHENIX PRC92.034913

±

h

PH ENIX

preliminary

[GeV/c]

T

p

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

b 2

e v

0.05

0.05 0.1 0.15 0.2 0.25

=200GeV

NN

s

Min. bias Au+Au

from bottom decay

±

e PHENIX PRC92.034913

±

h

PH ENIX

preliminary

ü Anisotropic Flow of c→e and b→e in Au+Au

19

v2 of c→e v2 of b→e

K. Nagashima - QNP 2018 - Nov. 16, 2018
PHENIX VTX analysis allow low pT v2 measurement
c-quark is strongly coupled in QGP, 0 < !"

#→% < !" &

> need unfolding and QCN scaling to direct comparison...

b-quark flow is likely less than c-quark flow in QGP

→ b-quark slightly flows? 0 < !"

'→% < !" #→%

SLIDE 20

ü Quark Mass Dependent Dynamics in QGP

20

K. Nagashima - QNP 2018 - Nov. 16, 2018

[GeV/c]

T

p 1 2 3 4 5 6 7 8 9

e) → e, b → (c

AA

R

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2

e (Phys.Rev.C 84,044905) → c+b e → c e → b =200 GeV

NN

s 0-10% Au+Au, Data 2004+2014, |y|<0.35 p+p from e-h correlations Phys.Rev.Lett.105,202301

PH ENIX

preliminary

Nuclear modification factor RAA Azimuthal anisotropy v2

V2 (c→e, b→e)

PHENIX has measured RAA and v2 of c, b→e

indicate quark mass dependent suppression and flow

→ will be improved with high stat. data and new baseline

V2 (c→e, b→e)

SLIDE 21

ü Summary

PHENIX has measured RAA and v2 for charm and bottom

in d+Au and Au+Au collisions at √sNN = 200 GeV

Cross-section of c"

c and b" b in p+p > obtain new baseline measurement for Au+Au > understood production mechanism from pair angle

v2 of c+b→μ in d+Au

> found non-zero v2 of c+b→μ in 0-20% d+Au

RAA and v2 of c, b→e in Au+Au

> indicate quark mass dependent suppression and flow > will be improved with high stat. data and new baseline

21

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 22

ü Backup

22

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 23

ü Heavy flavor measurement in Au+Au

Recode high statistics (Run14) AuAu data ~ 17 B events.
PHENIX VTX allow precise measurement of c+b→e.

> provides smaller photonic BG and higher RP resolution

Measurement of inclusive HF v2 is significantly improved.

23

[GeV/c]

T

p

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

HF 2

e v

0.05

0.05 0.1 0.15 0.2 0.25

Run2014 (with VTX) PRC84,044905 (w/o VTX)

=200GeV

NN

s

Min. bias Au+Au

from open heavy flavor

±

e

PH ENIX

preliminary

]

2

dy [(GeV/c)

T

N/dp

2

)d

T

p π (1/2

10 −

10

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10

Run14, min. bias Run4, min. bias Combined Fit

min. bias

[GeV/c]

T

p 1 2 3 4 5 6 7 8 Data/Fit 1 2

PH ENIX

preliminary

Invariant yield Azimuthal anisotropy v2

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 24

ü Extraction of c→e and b→e with DCA

24

T

DCA 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 counts 10

2

10

3

10

4

10

Data Re-fold Charm Bottom Background

=200 GeV

NN

s Au+Au, minimum bias, |y|<0.35 Data 2004+2014 [2.0-3.0 GeV/c]

[GeV/c]

T

p

1 1.5 2 2.5 3 3.5 4 4.5 5

e fraction

0.2 0.4 0.6 0.8 1 1.2 HFe charm bottom photonic hadron

=200GeV

NN

s

Min. bias Au+Au

|DCA|<0.02(cm) : charm enriched

PH ENIX

preliminary

[GeV/c]

T

p

1 1.5 2 2.5 3 3.5 4 4.5 5

e fraction

0.2 0.4 0.6 0.8 1 1.2 HFe charm bottom photonic hadron

=200GeV

NN

s

Min. bias Au+Au

0.03<|DCA|<0.1(cm) : bottom enriched

PH ENIX

preliminary

DCA distribution

Extraction of c→e and b→e v2

!"

# $%#& = ( #×!" # + (+×!" + + (+,×!" +,

!"

+ $%#& = ( #×!" # + (+×!" + + (+,×!" +,

Electron fraction

K. Nagashima - QNP 2018 - Nov. 16, 2018

Divide DCA region to charm rich and bottom rich.

c rich region: |DCA| < 200μm b rich region: 300 < |DCA| < 1000μm

SLIDE 25

ü Extraction of c→e and b→e with DCA

25

T

DCA 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 counts 10

2

10

3

10

4

10

Data Re-fold Charm Bottom Background

=200 GeV

NN

s Au+Au, minimum bias, |y|<0.35 Data 2004+2014 [2.0-3.0 GeV/c]

[GeV/c]

T

p

1 1.5 2 2.5 3 3.5 4 4.5 5

e fraction

0.2 0.4 0.6 0.8 1 1.2 HFe charm bottom photonic hadron

=200GeV

NN

s

Min. bias Au+Au

|DCA|<0.02(cm) : charm enriched

PH ENIX

preliminary

[GeV/c]

T

p

1 1.5 2 2.5 3 3.5 4 4.5 5

e fraction

0.2 0.4 0.6 0.8 1 1.2 HFe charm bottom photonic hadron

=200GeV

NN

s

Min. bias Au+Au

0.03<|DCA|<0.1(cm) : bottom enriched

PH ENIX

preliminary

DCA distribution Electron fraction

Extraction of c→e and b→e v2

!"

# $%#& = ( #×!" # + (+×!" + + (+,×!" +,

!"

+ $%#& = ( #×!" # + (+×!" + + (+,×!" +,

c rich region b rich region

Divide DCA region to charm rich and bottom rich.

c rich region: |DCA| < 200μm b rich region: 300 < |DCA| < 1000μm

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 26

[GeV/c]

T

p

1 1.5 2 2.5 3 3.5 4 4.5 5 HF 2

e v

0.05

0.05 0.1 0.15 0.2 0.25 |DCA|<0.02 charm enriched 0.03<|DCA|<0.1 bottom enriched

=200GeV

NN

s

Min. bias Au+Au

from open heavy flavor

2

e v

PH ENIX

preliminary

ü Extraction of c→e and b→e with DCA

26

T

DCA 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 counts 10

2

10

3

10

4

10

Data Re-fold Charm Bottom Background

=200 GeV

NN

s Au+Au, minimum bias, |y|<0.35 Data 2004+2014 [2.0-3.0 GeV/c]

DCA distribution

Extraction of c→e and b→e v2

!"

# $%#& = ( #×!" # + (+×!" + + (+,×!" +,

!"

+ $%#& = ( #×!" # + (+×!" + + (+,×!" +,

>> Solve simultaneous equations!

c rich and b rich v2

K. Nagashima - QNP 2018 - Nov. 16, 2018

Divide DCA region to charm rich and bottom rich.

c rich region: |DCA| < 200μm b rich region: 300 < |DCA| < 1000μm

SLIDE 27

ü Comparison of bottom anisotropic flow

27

K. Nagashima - QNP 2018 - Nov. 16, 2018

Pb+Pb, !"" = 5.02 TeV |y| < 2.0, 0-60% Pb+Pb, !"" = 2.76 TeV 1.6 < |y| < 2.4, 10-60% |y| < 2.4, 10-60%

ATLAS, CMS Non-prompt J/ψ PHENIX

ATLAS and CMS reported positive b-quark v2
PHENIX measurement provides new knowledge of b quark v2

for sensitive region of flow in QGP

b-quark v2 indicates non-zero positive value in pT: 1 - 30 GeV/c

→ b-quark slightly flows and loses energy in QGP?

QM18

SLIDE 28

ü Di-muon mass spectrum in p+p

high mass spectrum provides high S/B for ! ̅ !, #$ # and DY ! ̅ !, #$ # and DY cross sections are extracted with cocktail fitting

28

Like sign pairs Un-like sign pairs

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 29

ü Nuclear Modification of ! ̅ ! in p+Au

29

Di-muon analysis in p+Au at Forward-rapidity

Yield of b$

b is extracted from dimuon mass distributions

RpA shows no modification of b$

b

[GeV/c]

T

pair p 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 [c/GeV]

,2 µ

η d

,1 µ

η d

µ µ T,

N/dp

3

d 0.5 1 1.5 2 2.5

9 −

10 × X

±

µ

±

µ → b b

> 3 GeV/c

µ

p ] < 10.0

2

[GeV/c

±

µ

±

µ

3.5 < m = 200 GeV

NN

s < -1.2 (Au-going)

µ

η

2.2<

< 2.2 (p-going)

µ

η 1.2< x pp)

coll

|< 2.2 (N

µ

η 1.2< |

PH ENIX

preliminary

[GeV/c]

T

pair p 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

pA

R 0.5 1 1.5 2 2.5 3 X

±

µ

±

µ → b b

= 200 GeV

NN

s > 3 GeV/c

µ

p ] < 10.0

2

[GeV/c

±

µ

±

µ

3.5 < m < -1.2 (Au-going)

µ

η

2.2<

< 2.2 (p-going)

µ

η 1.2<

PH ENIX

preliminary

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 30

ü Bayesian Inference Techniques

30

Measured data dN/dpT, DCAT(pT)

!(#|%)'(%) Likelihood

[GeV/c]

T

p 1 2 3 4 5 6 7 8 9 ]

2

[(GeV/c) y d

T

p N/d

2

)d

T

p π (1/2

10 −

10

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10

Phys.Rev.C 84,044905 e (Data) → c+b

=200 GeV

NN

s Au+Au, 0-10% central, |y|<0.35

[cm]

T

DCA 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 counts 1 10

2

10

3

10

Data 2014

dN/(dpTdη) DCAT

DCAT [cm] pT [GeV/c]

Bayes’ theorem ! % # ∝ !(#|%)'(%)
Simultaneous fit to dN/dpT and DCAT(pT)
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 31

ü Bayesian Inference Techniques

31

Measured data dN/dpT, DCAT(pT) c/b hadrons dN/dpT

!(#|%)'(%) Likelihood

[GeV/c]

T

p 2 4 6 8 10 12 14 16 18 20 ]

2

[(GeV/c) y d

T

p N/d

2

)d

T

p π (1/2

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10

1 −

10 1

c hadrons b hadrons

- Hadron space --

A.U.

dN/dpT

pT [GeV/c]

172 parameters

Bayes’ theorem ! % # ∝ !(#|%)'(%)
Simultaneous fit to dN/dpT and DCAT(pT)
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 32

ü Bayesian Inference Techniques

32

Measured data dN/dpT, DCAT(pT) c/b hadrons dN/dpT → electron space

!(#|%)'(%) Likelihood

[GeV/c]

T

p 1 2 3 4 5 6 7 8 9 ]

2

[(GeV/c) y d

T

p N/d

2

)d

T

p π (1/2

10 −

10

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10

e → c e → b

A.U. pT [GeV/c]

[cm]

T

DCA 0.15 − 0.1 − 0.05 − 0.05 0.1 0.15 counts 1 10

2

10

3

10

e → c e → b

DCAT [cm]

- Decay electron space --

dN/dpT DCAT From PYTHIA6 decay model

Bayes’ theorem ! % # ∝ !(#|%)'(%)
Simultaneous fit to dN/dpT and DCAT(pT)
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 33

ü Bayesian Inference Techniques

MCMC sampling

Measured data dN/dpT, DCAT(pT) Yield of c/b hadrons → electron space regularization (smoothness)

!(#|%)'(%) Likelihood Parameter probabilities c/b hadron yields MCMC sampling 33

c hadrons b hadrons

Bayes’ theorem ! % # ∝ !(#|%)'(%)
Simultaneous fit to dN/dpT and DCAT(pT)
employ Markov Chain Monte Carlo (MCMC) for sampling
K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 34

ü Baryon Enhancement

34

Charm baryon enhancement is similar order of magnitude as Strangeness baryon enhancement

Strangeness baryon enhancement Charm baryon enhancement

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 35

ü Testing Possible Baryon Enhancement

Follow P. Sorensen and X. Dong

( Phys Rev C 74, 024902 (2006) )

Λ/Ks ratio measured

in STAR 20-40% Au+Au at 200 GeV and STAR in p+p at 200 GeV (arXiv:nucl-ex/0601042)

Fit both data
Fix asymptotic value to 0.3

in both Au +Au and p+p

Apply enhanced the ratio of

Λc/D and Λb/B to the decay matrices.

35

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 36

ü Testing Possible Baryon Enhancement

36

[GeV/c]

T

p 2 4 6 8 10 12 14 16 18 20 ]

2

[(GeV/c) y d

T

p N/d

2

)d

T

p π (1/2

9 −

10

8 −

10

7 −

10

6 −

10

5 −

10

4 −

10

3 −

10

2 −

10

1 −

10 1 c hadrons b hadrons c hadrons (enhanced) b hadrons (enhanced) =200 GeV

NN

s Au+Au, minimum bias, |y|<0.35 Data 2004+2014

Default decay matrix is

btained from PYTHIA model.

Decay matrix is modified

include baryon enhancement

Filled marker

use default decay matrix

Open marker

use modified decay matrix

Baryon enhancement effect is covered by current uncertainty c and b hadron yields

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 37

37

K. Nagashima - QNP 2018 - Nov. 16, 2018

SLIDE 38

38

K. Nagashima - QNP 2018 - Nov. 16, 2018