E.Kistenev, BNL

PHENIX in the next decade

4/30/2020

Erice, September 17, 2012

Slides contributed by J.Nagle, W.Zajc, D.Morrison, D.Karzeev, V.Pantuev

1

2002: discovery of high p T suppression at RHIC

Suppression of hadrons with large transverse momentum in central Au+Au collisions at √s NN PHENIX Collaboration ( K. Adcox

et al.

), Phys.Rev.Lett.88:022301,2002

664 citations

= 130 GeV,

D.Karzeev, 2004 RHIC II and dedicated program at RHICII are necessary to extend our understanding of collective QCD phenomena discovered at RHIC

-

Since 2002 the goal was to confirm that the observed high p T suppression is indeed due to the parton energy loss in the media:

Search for fluctuations –> transport coefficients; Energy scan -> search for critical point; Studies of the suppression dependence on the quark mass; Studies of the suppression dependence on collision energy (RHIC vs LHC);

CMS, PbPb, Isolated photons, 2.76 TeV

Systematic investigation of variations with



s

4

2.76 TeV at LHC very similar to 200 GeV at RHIC!

The Intellectual Challenges and Rewards

 Challenge: Solving a multi-scale, highly dynamic transport problem in an intrinsically quantum .

system  Rewards:    Possible resolution of quasiparticles Measurement of shear viscosity to entropy ratio h /s Measurement of transport coefficients 2

p T L L

ˆ 

L L

in a fundamental gauge theory W.Zajk, Tribble com. talk

Mapping Out Media Coupling with Jet Probes

In a weakly coupled turbulent plasma

q

 1 .

25 h /

s

3

Key is independently measuring both sides of this equation!

QCD Weak Case Scenario #1 (x10) ^ reveals peak in q !

RHIC Perfect Fluid

A. Majumder, B. Muller, X.N. Wang, PRL (2007).

“Small Shear Viscosity Implies Strong Jet Quenching”

Liao and Shuryak, PRL (2009)

“Jet Quenching is a few times stronger near T c relative to the QGP at T > T c .” 6

Indirect “bounding”

h

/s at RHIC



Range of estimates:



(Compilation by A. Tang, R.J. Lacey)



Estimated “error band”

PHENIX, PRL (2010)

“Large v 2 is striking in that it exceeds expectations of pQCD models even at 10 GeV /c”

J.Liao arXiv:1209.1052v1 [nucl-th] 5 Sep 2012

“AdS/CFT-motivated model with cubic path-length which enhances the late time quenching that mimics the near-Tc enhancement describes v2 at high pt for RHIC”

Jet/photon tagging for q measurements

Jet or photon

Fractional momentum loss

Measure fractional momentum loss (dp T /p T ) instead of R AA

RHIC and LHC give a key lever arm in temperature

p T

Different dp T /p T for same R AA

LHC RHIC arXiv:1208.2254

Analogy: e - energy loss in electrical field Horowitz and Gyulassy, NPA (2011)

“The surprisingly transparent sQGP at the LHC [compared to RHIC]”

Can RHIC precisely measure key observables

Based on full stochastic cooling, no additional accelerator upgrades

>20GeV >30GeV >40GeV

Au+Au (central 20%)

10 7 10 4 jets photons 10 6 10 3 jets photons

p+p

10 6 10 3 jets photons 10 5 10 2 jets photons 10 5 jets 10 4 jets

d+Au

10 7 10 4 jets photons 10 6 10 3 jets photons 10 5 jets >50GeV 10 4 jets 10 3 jets 10 4 jets

Rates are huge. They will allow differential measurements with varying collision geometry (v 2 , v 3 , A+B, U+U, …) & precision control measurements (d+Au and p+p) !!

Further Leveling the playing field with LHC

Use advantages of RHIC (machine is dedicated to HI physics); Vary the species (shape, isotopic content); Study threshold behavior varying collision energy; Do better measurements LHC comparable or increased coverage; comparable or better resolution; better hermeticity, uniformity

sPHENIX Decadal Plan

ambitious upgrade to study the sQGP with a new compact, hermetic, large acceptance and high rate calorimetry based detector High statistics

Upsilons

, large

Dijet

and g

-jet

rates with full calorimetry,

photon/charm/beauty

tagging of jets with PreShower/VTX,

low-x jet,

g

, quarkonia, transverse spin probes, staged into ePHENIX detector

.

Specs for NEW sPHENIX Central Detector

13

4/30/2020

sPHENIX MIE Project ( major item of equipment )

Magnet

• Solenoid 2 Tesla, R inner = 70 cm

Accordion Tungsten-Fiber EMCal Fe-Scintillator HCal

• Also acts as flux return for magnetic field 4/30/2020

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Full HIJING Event Analysis

truth jets 18GeV reconstructed jets 16GeV 19GeV 6GeV Jet Transverse Energy (GeV) 15GeV Very good jet finding efficiency even in the most central Au+Au events for E T > 20 GeV

4/30/2020

25-30 GeV reconstructed Jets are dominated by real jets (known from HIJING truth) 15

sPHENIX Electromagnetic Calorimeter

16

4/30/2020

sPHENIX Hadron Calorimeter Tilt tuneup (mip’s)

Response ~ 75%/√E

First look on HC performance

18

Summary

Heavy Ion Collisions produced major discoveries in “Physics in Collisions” in the last 10 years, jet quenching and unexpectedly strong elliptic flow are two examples.

In the era of LHC RHIC still offers unique opportunities for detailed studies of matter phase transition on a phase boundary close to critical temperature.

We need the lever arm of RHIC and LHC together to find a fundamental explanation for how the perfect fluid emerges at strong coupling near T c from an asymptotically free theory of quarks and gluons.

Calorimetry based upgrade to PHENIX will create a tool to explore this opportunity with jets and direct photons being event observables and event tags of choice.