Yale RHIG High pT Contributions

Boris Hippolyte: 1st year postdoc

Jon Gans: 5th year grad

Michael Miller: 5th year grad

Oana Catu : 2nd year grad

Christine Nattrass: beginning grad

John Harris: Physics Leader

September 2003 Mike Miller

What we’re doing now: PhysicsPhysics

•C. Adler et al.: Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at sqrt(s_NN)=130 GeV; Phys. Rev. Lett. (87), 112303 (2001)

•C. Adler et al.: Centrality Dependence of High pT Hadron Suppression in Au+Au collisions at sqrt(s_NN)=130 GeV; Phys. Rev. Lett. 89, 202301 (2002) nucl-ex/0206011.

•C. Adler et al.: Disappearance of back-to-back high pT hadron correlations in central Au+Au collisions at sqrt(s_NN)=200 GeV; Phys. Rev. Lett. 90, 082302 (2003)

•J. Adams et al: Evidence from d+Au measurements for final-state suppression of high pT

hadrons in Au+Au collisions at RHIC; Phys. Rev. Lett. 91, 072304 (2003)

•J. Adams et al., Transverse momentum and collision energy dependence of high pT hadron suppression in Au+Au collisions, submitted to Phys. Rev. Lett.

•J. Adams et al., Multi-Strange Baryon Production in Au+Au collisions at sqrt(s_NN)=130 GeV, submitted to Phys. Rev. Lett.

•M.L. Miller and R. J. Snellings: Understanding the effect of Geometry Fluctuations on High pT Elliptic Flow Measurements at RHIC; To be submitted to Phy. Rev. Lett.

Yale RHIG primary authored high pT papers

2002-2003: 11 invited and 5 contributed high-2002-2003: 11 invited and 5 contributed high-ppTT presentations presentations (Gans, Hippolyte, Miller)(Gans, Hippolyte, Miller)

September 2003 Mike Miller

Why Jets? Energy Loss in Dense Matter

Strong dependence of energy loss on gluon density glue• measure measure gluon density at early hot, dense phase Deconfined quarks and gluonsDeconfined quarks and gluons

Thick plasma (Baier et al.):

glueSglue

Debye

sRBDMS

q

vLqC

E

2

2

ˆ

~ˆ4

L

ELogrdCE jet

glueSRGLV 23 2

,

Thin plasma (Gyulassy et al.):

Gluon Bremsstrahlung

September 2003 Mike Miller

Yale High pT Focus

•Identified particle yields: pion, kaon, proton spectra with RICH detector (B. Hippolyte)

•Inclusive charged particle yields: h++h- spectra (J. Gans)

•2-particle high pT hadron correlations: jet, di-jet structure and yields (M. Miller, O. Catu, C. Nattrass)

•Topological Jet ID: tagged jet, di-jet spectra. (Identified particle) Fragmentation function measurements (all)

Show all in 15 minutes? No chance!Show all in 15 minutes? No chance!

September 2003 Mike Miller

Identified Hadron Spectra from RICH

Chemical propertiesChemical properties: temperature, chemical potential, flow: temperature, chemical potential, flowSoft vs. Hard PhysicsSoft vs. Hard Physics: Sensitive to gg, qg, qq contributions: Sensitive to gg, qg, qq contributions

September 2003 Mike Miller

Identified Hadron Spectra from RICH

Chemical propertiesChemical properties: temperature, chemical potential, flow: temperature, chemical potential, flowSoft vs. Hard PhysicsSoft vs. Hard Physics: Sensitive to gg, qg, qq contributions: Sensitive to gg, qg, qq contributions

September 2003 Mike Miller

200 GeV Charged Hadron Spectra

p+p spectrum: first at 200 GeV

High event rate, backgrounds vertexing bias => Problems solved by J. Gans

p+p: absolutely normalized

Methods/solutions applicable in d+Au

September 2003 Mike Miller

1

10-1

s 200 GeV

STAR Preliminary

Charged RAA: Comparison to Theory

collisions

AuAuRatio

N pp

pQCD:Vitev and Gyulassy, PRL 89, 252301 XN Wang, to be published (see also nucl-th/0302007

pQCD: good agreement; gluon density ~15 x cold nuclear matterpQCD: good agreement; gluon density ~15 x cold nuclear matter

No E-LossNo E-Loss

E-LossE-Loss

September 2003 Mike Miller

Charged RdAu: Turning off Final State

collisions

dAuRatio

N pp

High High ppTT Suppression is a Final State Effect! Suppression is a Final State Effect!

No suppression for minimum bias d+AuNo suppression for central d+AuWhat’s happening At pT>8 GeV/c?

Jon’s Thesis Cover

September 2003 Mike Miller

First Observation of Jets at RHIC

trigger

Near Side Far Side

s=200 GeV p+p

Can find this…

In this…

September 2003 Mike Miller

Jets In Most Violent CollisionsAdams et al., Phys.Rev.Lett. (91):072304,2003

“Near side” jet identical! pp=dAuAuAu

Disappearance of away-side jet is a Final State Disappearance of away-side jet is a Final State Effect!Effect! Jet Quenching Jet Quenching

Background subtracted

s=200 GeV

Mike’s Thesis Cover

September 2003 Mike Miller

Where are we? Where to go? Jets at RHIC are now well

established, excellent probe of medium

Produce strongly interacting, highly opaque matter

High pT suppression is most likely post-hard scattering phenomenon

Tagged jet fragmentation: distinguish hadronic vs. partonic E-

Loss Jet triggered data in p+p, d+Au (Oana

and Christine in progress)

September 2003 Mike Miller

Yale Contributions to STAR High pT

• New global reco software (Miller)

• RICH Reco (Hippolyte)• New V0 reco software (Betty,

Caines, Hippolyte)• Database and calibrations

(Gans)• Vertexing software (Gans,

Miller)• Jet finding software (Miller)• SVT Software (Betty, Caines,

Salur)

• SVT hardware (Caines)

• STAR II Hardware (Smirnov)

• Forward Tracking upgrade (Smirnov, Miller/MIT)

SoftwareSoftware HardwareHardware