measurement of phi and omega @rhic-phenix

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Measurement of phi and omega @RHIC-PHENIX

Misaki Ouchida

ｆ or the PHENIX Collaboration

Hiroshima University

What is expected? Hadron suppression C.S.R. signal

（ Flow → Talk by D.W.)

（ Continuum → Talk by S.C.)

What we have ?

outline

2010 WWND

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Misaki Ouchida2010 WWND

What is expectedHigh pT physicsHigh pT physics

Hadron SuppressionHadron SuppressionThe inclusive pi0 production in Au+Au

PRL 91. 072301 (2003)

QGP

Hadron Production will be suppressed due to the jet quenching occurred in the heavy-ion collisions as an effect of the matter

ssuudd

How phi & omega How phi & omega behave?behave?

Temperature

Density

RHICRHIC

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What is expectedHigh pT physicsHigh pT physics

Hadron SuppressionHadron Suppression

PRC 77. 064907 (2008)

QGP

Hadron Production will be suppressed due to the jet quenching occurred in the heavy-ion collisions as an effect of the matter

ssuudd

How phi & omega How phi & omega behave?behave?

Temperature

Density

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Low pT physicsLow pT physics

TemperatureDensity

Chiral Symmetry RestorationChiral Symmetry Restoration

Hot/dense matter Hot/dense matter ↓↓Quark condensate decreaseQuark condensate decrease↓↓changes hadron mass changes hadron mass properties in mediumproperties in medium

What is expected

<qq>quark condensate

-

Measurements of vector mesonsMeasurements of vector mesons Access quark condensate with theoretical calculationsAccess quark condensate with theoretical calculations

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PredictionModel PredictionModel Prediction

Unfortunately, quark condensates Unfortunately, quark condensates is not an observableis not an observable Link condesates and vector mLink condesates and vector meson spectrumeson spectrum

- Lowering of in-medium mass?- Lowering of in-medium mass?- Broadening of resonance?- Broadening of resonance?

R. Rapp, Phys. Rev. C63(2001) 054907

T.Hatsuda and S.Lee Phys.Rev.C46-1 1992

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PHENIX spectrometer<Global detector>• BBC & ZDC : Event trigger, Collision vertex, Centrality <Central arm>•DC & PC : tracking, momentum• RICH & EMC : electron ID• TOF, EMC : hadron ID<Muon arm>• MuID : muon ID

How do we measure?

PHENIX acceptancepseud-rapidity range : |η| < 0.35azimuthal angle : 2x90 degree

φ mesons (= 46fm/c)

φ→e+e- BR ~ 10-4

φ→K+K- BR ~ 50 %

ω mesons (= 23 fm/c)

ω→e+e- BR ~ 10-5

ω→π0γ BR ~ 9 % ω→π0π+π- BR ~ 90 %

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Systematic Measurement-different decay mode (lepton, hadron)

Rec

on

stru

cted

Rec

on

stru

cted

Eff

icie

ncy

Eff

icie

ncy

e+e- (BR:7x10-3%)

(BR:9%)

ωpTωpT

Can Approach to high pT

Advantage of Systematic Measurement- Leptonic Decay mode: no final distortion

- Hadronic Decay mode: high BR,

no ρ-contribution (e+e- case)

- Wide kinematic coverage

- Reference study (comparing collision system)

- Line Shape Analysis (BR check)

-different collision mode (p+p, d+Au, A+A)

e+

e-

K+

K-

φ mesons

φ→e+e- BR ~ 10-4

φ→K+K- BR ~ 50 %

ω mesons

ω→e+e- BR ~ 10-5

ω→π0γ BR ~ 9 % ω→π0π+π- BR ~ 90 %

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So far, what we have ?So far, what we have ?

Collected Data (√s = 200 GeV)

- p+p (run5) - d+Au (run3, run8) - Cu+Cu (run5) - Au+Au (run4)

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p+p

φ e+e-

+-

p+p

Both leptonic andhadronic decay channel are measured

Base Line – p+p

φ K+K-

φ K+K-

No PID methNo PID method was introdod was introduced to exteuced to extend the accepnd the acceptance to hightance to higher pT er pT

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d+ Au

d+ Au

φ e+e-

Base Line – d+Au

Both leptonic andhadronic decay channel are measured

φ K+K-

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• Spectra (p+p & d+Au)

Base Line

dAudAu

pppp

Results are consistent Fitting of Levy fun

c.

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• Spectra (p+p & d+Au)

Base Line

Results are consistent

dAudAu

pppp

Fitting of Levy func.

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R_dAu

No suppression in d+AuNo suppression in d+Au

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In the case of A+AIn the case of A+A

Yield analysisYield analysis

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Subtracting Backgrounds ( 2 body: φ e+e-φ K+K- )

φBG

BGcombinatorial backgroundsextract

by Event Mixing

→eeBGSignalSignal

Trails – A+A

→K+K-

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Black: FG

[GeV/c^2]

Peripheral (cent 60~92 %)3.5<pT<4.5[GeV/c]

Magenta: Uncorrelated BG + Correlated BG2 + Ks contribution

BG3

BG2

BG1

Gaussian (Mean and With are Fixed by Embedding simulation)

after subtraction of

BG1+BG2+BG3

coun

t

Reconstructed invariant mass

Subtracting Backgrounds ( 3 body: ( 2)

Trails – A+A

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• Spectra (Au+Au)

Results & Discussionφ , φ e+e- @ Au+Au

MBMB

Suppression of phi in central collisionNo significant modification observed?

0 - 20%0 - 20%

20 - 40%20 - 40%

40 - 92%40 - 92%

PHENIX Preliminary

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• Spectra (Au+Au) , e+e- @ Au+Au

Results & Discussion

MBMB

20 - 60%20 - 60%

0 - 20%0 - 20%

60 - 92%60 - 92%

Suppression of omega in central collision

Scaled fromp+p spectra

PHENIX Preliminary

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Results & Discussion

The results are consistentBetween CuCu and AuAu

- Baryon/meson difference is apparentBaryon/meson difference is apparent- Suppression pattern of pi0 and eta is sameSuppression pattern of pi0 and eta is same- phi at intermediate pT do not follow pi0 and etaphi at intermediate pT do not follow pi0 and eta- omega in high pT needs more dataomega in high pT needs more data- All suppression patterns are similar at high pTAll suppression patterns are similar at high pT

R_AA (CuCu and AuAu)

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Issues and Outlook

signal electron

partner positronneeded for rejection

- The discussion in low pT physics is hard due to low statistics and S/N The discussion in low pT physics is hard due to low statistics and S/N - Run10 is now taking AuAu dataRun10 is now taking AuAu datawith activated HBDwith activated HBD e+ e -

e+ e -

“combinatorial pairs”

all signal

Able to reduce the BGfrom Dalitz and γconversion

Dalitz rejectorHadron Blind Detector

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Summary• PHENIX measured Low Mass Vector Meson, omeg

a and phi production in both leptonic and hadronic channels in different collision system.

– Spectra show good agreement in p+p and d+Au

– Mass modification discussion is hard to discuss – Yield measurement provide intriguing systematic

results of hadron suppression.

Base line

A+A

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measurement of phi and omega @rhic-phenix

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