kek seminar, 5/nov/2008univ. of tsukuba, shinichi esumi1 jet correlation (mach-cone, ridge) at rhic...

KEK seminar, 5/Nov/2008 Univ. of Tsukuba, ShinIchi Esumi 1

Jet correlation (Mach-cone, Ridge) at RHIC

ShinIchi Esumi Inst. of Physics, Univ. of Tsukuba

Contents•Jet-Suppression and Modification•Mach-cone and Ridge•Identified Particle Correlation•Correlation w.r.t. Reaction Plane


Au + Au

Use Jet as a probe of High-Energy and Density Matter Jet in p+p, d+Au or Peripheral Au+Au Collision as a Base Line Subtraction of Non-Correlated BG in Central Heavy-Ion Collisions

p + p Au + Aud + Au


RHIC 200GeV SPS 17GeVRHIC 62GeV

PHENIXnucl-ex/0611019

S.Kniege, ISMD 2007

jet

p p

Au Au

Jet suppression modification with 2-particle correlation


p+p vs Au+Au cent 60-92%


p+p vs Au+Au cent 0-20%


STAR, Phys. Rev. Lett. 97 (2006) 162301

8 < pT(trig) < 15 GeV/c


Away RegionShoulder Region Head RegionShoulder Region

Near Region

large BG subtraction with v2 like flow shape

regiondouble peak region

Same Side Far Side

description of jet shapewith several key words


Phys. Rev. Lett. 97, 052301 (2006) Leadinghadrons

Medium

PRL 98 232302 (2007)


System Size and Beam Energy Dependence of Jet Shape

nucl-ex/0611019

No energy dependence (62 ~ 200GeV)Rapid change between Npart = 0 ~ 100Almost no change above Npart > 100


arXiv:0801.4545

Transverse Momentum (Trigger, Associate) Dependence of Jet Shape

Suppression in both near/away side peak at high pT

Enhancement in near side peak at low pT

Development of away side shoulder at low pT

No pT dependence of shoulder peak position


STAR Preliminary

(1-2)/2

(1-2)/2

STAR Preliminary

Cone angle (radians)

pT (GeV/c)

d+Au Collisions

Au+Au Central 0-12%

3-particle correlation “12 vs 13”

No pT dependence, too.

Trigger

Asso.1

Asso.2

Asso.2


along azimuth

Polar plot

3 Particle Correlations in High pT Framework (*)

Normal Jet

Same Side

Away Side

*φ

*θ

Assoc. pTs (2,3)

*θ12

*θ =

along radius

*12

*13

* _=

Hi pT(1)


Deflected jet sim

3-Particle di-jet correlations allow a distinction between different mechanistic scenarios !

Mach Cone sim

Deflected and Cone Jet Sims

2-particle Correlations matched

High pT(1) High pT(1)


θ*=

*=

PHENIX Preliminary PHENIX Preliminary

Cone like Jets

Deflected Jets

Deflected jet simulation Mach Cone simulation


p+p, peripheral Au+Au central Au+Au PHENIX QM08

d+Au, 200 GeV STAR QM06

(rad)

RidgeRidge

“jet”

Au+Au, 200 GeV


preliminaryJet+Ridge ()Jet ()Jet)

　　　

yie

ld

,

)

Npart

Au+Au 0-10%

RidgeRidge

“jet”

STAR QM06


QM08 PHENIX

Centrality Dependence of Ridge and Shoulder Yield and <pT>

Both ridge and shoulder yields increase linearly with Npart. Similar (flat) centrality dependence on inverse slope parameter for both ridge and shoulder.Jet (p+p) like pT shape is harder than ridge, ridge is harder than shoulder, shoulder is similar to inclusive.


STAR Preliminary

TInclusive ~ TShoulder ~ TRidge < TJet

QM06

QM08

ridge

jet

inclusive

< <

Both ridge and shoulder <pT> are almost independent with centrality and trigger pT selections.It’s just like a bulk matter… suspicious on BG(bulk) subtraction… but this is what we see…


yt1

yt2

transverse correlations

yt ~ ln(pt)

0.5

1

2

34

pT (Gev/c)

STAR Preliminary

2-particle correlation without high pT trigger selection

200GeV p+p

hard component

ηΔ

φΔ

soft component

ηΔ

φΔ

Longitudinal Fragmentation (“strings”) 1D Gaussian, US pairsHBT peak at origin, LS pairs

Minijets 2D Gaussian at origin, away-side peak actually cos(φΔ)

J of Phys: Conf 27 (2005) 98

These structures define minijet cor

relations

M. Daugherity, QM08

axial correlations

ηΔ

φΔ


longitudinal fragmentation1D gaussian

HBT, res., e+e-2D exponential

Minijet Peak2D gaussian

Away-side -cos(φ)

ΔηΔφ

Elliptic flowcos(2φΔ)

1.2M minbias 200 GeV Au+Au eventsIncluded all tracks with pT > 0.15 GeV/c, || < 1, full φ

84-93%

28-38%

75-84%

19-28%

65-75% 55-65% 46-55%

9-19% 5-9% 0-5%

M. Daugherity, QM08

STAR Preliminary


Centrality

200 GeV62 GeV

STAR Preliminary STAR Preliminary STAR PreliminaryPeak Amplitude Peak η Width Peak φ Width

HIJING 1.382 default200 GeV, quench off

binary scaling assumptionin Kharzeev and Nardi model

data - fit (except same-side peak)

Shape changes little from peripheral to the transition

83-94% 55-65%

ηΔ width

STAR Preliminary

STAR Preliminary

Large change within ~10%

centrality

46-55%

STAR Preliminary

Smaller change from transition to most central

0-5%

STAR Preliminary

QM08 STARE

xtracted 2-D near-side G

aussian param

eters are shown. T

he strong

width change vs centrality should h

ave a relation to the ridge formatio

n.

longitudinal (densitycorrelation length


arXiv:0712.3033

Near/Away-side B/M ratio increases in centralAway-side B/M ratios approach inclusive valuesIncompatible with in-vacuum fragmentation

Hadron trigger with identified associate Baryon/Meson


Baryon/meson ratio in ridge close to inclusive, in jet close to p+p

pTtrig > 4.0 GeV/c

2.0 < pTAssoc

< pTtrig

C. Suarez et al, QM08 M. Lam

ont et al, QM

05 J. Bielcikova et al, W

WN

D07, C

. Nattrass et al, Q

M08

Different production mechanisms for ridge and jet?

Au+Au: 2 < pTtrig < 3 GeV/c

Cu+Cu: 3 < pTtrig < 6 GeV/c

p+

p /

++-

Associated baryon/meson ratios


Idea: Distinguish

and

No acceptance

1 jet-like associated, 1 ridge-like:Bands along axes

Both ridge particles on one side: diagonal structure

Ridge particles on either side:uniform -

12

trigger

No acceptance

Ridge event-by-event: 3-particle


STAR Preliminary

dAu

AuAu0-12%

STAR Preliminary

STAR Preliminary

dAu

AuAu0-12%

3<pTTrig<10 GeV/c

1<pTAsso<3 GeV/c

Shaded : sys. error.

Line : v2 uncer.

STAR Preliminary

dAu

AuAu0-12%

P. Netrakanti et al, QM08

Note : 2x1 b.g. subtracted

Radial distribution

- structure: central peak + uniform

No substructure in ridge: no gluon fragments?

Note absence of excess along axes: no jet+ridge events?

STAR Preliminary

- results


|ηtrig|<13<pT

trig<10 GeV/c

2.7<|ηassoc|<3.90.2<pT

assoc< 2 GeV/c


Trigger: MTPC: 3<pTtrig<4 GeV/c,

Associated: FTPC: 0.2<pTassoc< 2 GeV/c, MTPC: 0.2<pT

assoc< 3 GeV/c

pp MBdAu MB

AuAu 60-80%AuAu 0-10%AuAu 0-5%


PHENIX preliminary

Identified 0 trigger with associate hadron

Width does not change with centrality similar to charged hadron triggered case.

7-9 (X) 1-20-20%

7-9 (X) 4-50-20%

7-9 (X) 4-520-40%

7-9 (X) 4-540-60%

7-9 (X) 4-560-90%

7-9 (X) 6-840-60%

QM08 PHENIX


1/N

trig

dN

/d

(A.U

.)

pT, photon GeV

Per-

Tri

gg

er

Yie

ld (

A.U

.)

Run 6 p+p @ 200 GeV

0

Run 7 Au+Au @ 200 GeV, cent=0~20%, preliminary

Direct trigger with associate hadronQM08 PHENIX

p+p: C

onsistent with trigger photon carr

ying the full jet energy, away side jets ar

e similar betw

een 0 and

triggers.

Need m

ore studies and statistics for A

u+A

u case.

Run 4/5 p+p/Au+Au @ 200 GeV


3<pTtrig<4GeV/c & 1.0<pT

asso<1.5GeV/c 20-60%STAR

= associate - trigger (rad)

Jet modification and geometry(and v2)

QM08: STAR, PHENIX

QM04: STAR

Mach-cone shape depends on R.P. angle.Mach-cone is a source of of v2


STAR Preliminary

Rid

ge

Jet

3<pTtrig<4, 1.5<pT

trig<2.0 GeV/c

QM08 STAR

STAR

(rad)

RidgeRidge

“jet”Au+Au, 200 GeVRidge/Cone and

geometry (v2)

Ridge shape depends on R.P. angle.Ridge is a source of of v2

Jet does not depends on itJet reduces v2

Jet

Rid

ge

Shou

lder

(co

ne)

Hea

d (

)Rid

ge

Shou

lder

(co

ne)

v2

v2


(rad)

PYTHIA p+ptrigger

near side

away sidey

x

(1) away side of a back-to-back(b-t-b) jet is wider in than in (2) If there are two parallel b-t-b jets, away side of one b-t-b jet can be

near side of the another b-t-b jet.(3) Suppression as well as modification of b-t-b jet would depend on re

lative angle w.r.t. almond geometry, we know this from v2 measurement and believe this is the major source of v2 at high pT .

(4) Therefore, there should be inter b-t-b jets correlation give by the geometry from (3), this could make near side ridge like effect, especially if the effect (3) has shaper dependence than v2(=cos2x).

(5) We always measure inclusive v2, which includes the effect (3). Therefore any modification which could generates the elliptic anisotropy would be included in the measured v2 .

(6) We subtract BG contribution with this v2 from (5) by maximizing BG contribution assuming zero jet yield at minimum at any d.

(7) If near and away side jets overlap each other, this subtraction underestimates the jet yield and can change the extracted jet shape.

(8) If you extract angular dependence of jet w.r.t. R.P., the results will easily be affected by the choice of v2 from (5).


AMPT 200GeV Au+Au → charged hadrons (|y|<2.0)

string-melting 10mbstring-melting 3mbdefault AMPT 3mb

b = 12 fm ~ b = 8~12 fm b = 4~8 fm b = 0~4 fm

1/N

trig

. dN

asso

./d|

trig

.-as

so.|

|trig.-asso.| (rad)

pTasso. : 0.7-1.7GeV/c

pTtrig. : 1.7-4GeV/c


AMPT 200GeV Au+Au → charged hadrons (|y|<2.0)pT

asso. : 0.7-1.7GeV/cpT

trig. : 1.7-4GeV/c

trigger at in-planeaveragetrigger at out-of-plane

b = 12 fm ~ b = 8~12 fm b = 4~8 fm b = 0~4 fm

|trig.-asso.| (rad)

1/N

trig

. dN

asso

./d|

trig

.-as

so.|


(1)

(2)

(3)

(4)

(2)

(3)

(4)

(1)

Trigger

particle

x(R.P.) x(R.P.)

yy

(2)Trigger

particle

ASSO.TRIG.

associate particle direction at

same || w.r.t. trigger particle

but with different arrow length

associate particle direction at

same || w.r.t. red dashed line

but with different arrow length

In order to study the jet modification (mach-cone, ridge) and it’s relation with almond geometry in more detail…

with and without R.P. aligned event mixing


AMPT 200GeV Au+Audefault option melting-on

0~9%

9~19%

19~39%

39~100%

(1) (2) (3) (4) (all)(1) (2) (3) (4) (all)

0~9%

9~19%

19~39%

39~100%


Summary and Conclusion・ 2- and 3- particle correlation and transverse momentum dependence of jet-modification tells us that it is likely a mach-cone. ・Mach-cone and ridge are almost as soft as inclusive particles. ・ Identified particle (baryon, meson, 0, ) correlation measurements.・Mach-cone and ridge w.r.t. reaction plane angle tells us that this is a part of v2


Extra and Back-up Slides


PRC71 0519022.4<pT

Trig<4 GeV/c 1.7< pTAsso<2.5 Ge

V/c

Identified Baryon/Meson trigger with associate hadron

Enhanced near-side yield can not be explained by soft process like thermal recombination alone.


R.P.

(1)(2)

(3)

(4)

(5)

(6)(7)

(8)ave (1)~(8)

ave (1),(8) ave (2),(7) ave (3),(6) ave (4),(5)

(1) (2) (3) (4)(8) (7) (6) (5)

Pure Flow Simulationwith trigger angle selection w.r.t. R.P.with/without R.P. aligned event mixing

wit

hout

R.P

. ali

gned

eve

nt m

ixin

gw

ith

R.P

. ali

gned

ev

ent m

ixin

g

(1) (2) (3) (4)(8) (7) (6) (5)


Au+Au vs. Cent @ /4Au+Au vs. RPInclusive Au+Au

• Inclusive correlation Au+Au – Example: 0-5%– Modest flow in this bin– Background subtraction can only make effect more pronounced

• Choose a trigger orientation with minimal impact from modulated background– 4th bin: ~ /4 (grey circles)

• Example: Au+Au in 4th RP bin, several centralities– “mach cone”(?) effect clear without any subtraction– Need to focus on source of shoulder!

Medium effects w/o subtraction?

kek seminar, 5/nov/2008univ. of tsukuba, shinichi esumi1 jet correlation (mach-cone, ridge) at rhic...

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