PHENIX RHIC R K CHOUDHURY BARC

PHENIX @ RHIC R. K. CHOUDHURY BARC

Relativistic Heavy Ion Collider at Brookhaven National Laboratory (BNL), USA World’s First Heavy Ion Collider became operational in 2000 PHENIX, STAR, PHOBOS & BRAHMS

Relativistic Heavy Ion Collider @ BNL Facts about RHIC n n n n Tunnel: 3. 66 m wide under the ground Circumference: 3. 84 km Au Beam @200 Ge. V/n speed: 99. 995 % of c 1000’s of collisions per second 1000’s of particles produced per collision T ~ 1012 K >> T (centre of the sun) 107 K Spin polarized proton beam upto 500 Ge. V/n

PHENIX: Pioneering High Energy Nuclear Interaction e. Xperiment. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, phtons and hadrons.

International Aspect of PHENIX n n 12 Countries, 58 Institutions, 480 participants: Country: Brazil, China, France, Germany, Hungary, India, Israel, Japan, Korea Russia, Sweden, USA

PRIMARY MOTIVATION (Physics Driven) 1. Study of Quark Gluon Plasma (To create a mini universe in the laboratory what might have existed a few micro seconds after the big bang) 2. To understand the origin of Proton Spin

To map out the QCD phase diagram

What happens when two Au ions collide heads on ?

What happens inside a Detector ?

Off Line Analysis Begins Pattern Recognition

BARC CONTRIBUTION Fabrication of Muon Tracking Stations Simulation and Reconstruction Software

PHENIX RUN STATISTICS Run 01 2000 Au+Au @ 65 Ge. V/n for 5 weeks Run 02 2001 Au+Au @ 100 Ge. V/n for 16 weeks Run 03 2003 d+Au @ 100 Ge. V/n for 10 weeks Run 04 2004 Au+Au @ 100 Ge. V/n for 12 weeks Run 05 2005 Cu+Cu @ 100 Ge. V/n for 8 weeks Pol. p+p @ 100 Ge. V/n for 9 weeks Run 06 pol. p+p at 100 Ge. V/n for 14 weeks

Results from PHENIX (HI runs) n n n n n -- Charged particle Multiplicities (stopping) -- Transverse Energy ( ~ 5 Ge. V/fm 3) -- Particle Yield Ratios, energy spectra (thermalisation) -- Elliptic Flow (v 2 scales with eccentricity: high collectivity) -- Two particle correlations -- Non-statistical Fluctuations -- Suppression of particle production at high p. T -- Jet suppression -- Heavy flavour production (open charm, J/psi) -- Large (anti)baryon to pion ratio at intermediate p. T

Heavy Flavour Physics 1. Heavy flavour cross section: -->Calculable with QCD also include effects such as Shadowing -->Measure the cross section in pp, p. Pb and then extrapolate to Pb. Pb 2. Cold matter effects: --> Nuclear absorption and Comover scattering, e. g. J/psi + N --> D + D bar+ X 3. Energy loss in the medium: 4. Quarkonium suppression in QGP: When screening radius r. D < r. QQbar, at T > TD 5. Quarkonium Enhancement at LHC: No. of Q Qbar pairs produced at LHC is large. Possibility of recombination

PHENIX - J/y Suppresion system size dependence J/y mm muon arm 1. 2 < |y| < 2. 2 J/y ee Central arm -0. 35 < y < 0. 35 Factor ~3 suppression in central events d. Au Au. Au Cu. Cu ee ee mm mm mm 200 Ge. V/c Cu. Cu mm 62 Ge. V/c

PHENIX - J/y Suppresion comparison to theory Models that were successful in describing SPS data fail to describe data at RHIC - too much suppression -

PHENIX - J/y Suppresion comparison to theory Implementing regeneration: much better agreement with the data

Suppressed high p. T hadroproduction in Au+Au p 0 X (peripheral) (central) Peripheral data agree well with Au+Au p 0 X Strong

Suppressed high p. T hadroproduction Ncoll scaling (“hard” production) x 5 suppression Npart scaling (surface emission) RAA << 1: well below p. QCD (collinear factorization) expectations for hard scattering cross-sections Discovery of high p. T suppression (one of most significant results @ RHIC so far)

Evidence in Favor of QGP Jet Tomography

Jet Quenching Data

A Strong Collective Behavior: FLOW

Definition of flow? Φ: azimuthal angle relative to reaction plane. f (Φ): azimuthal distribution of particles. Make Fourier expansion of f (Φ). 1 st Fourier coefficient v 1 = directed flow 2 nd Fourier coefficient v 2 = elliptic flow vn = <cos (nΦ)>, n = 1, 2, … Central collision: vn=0, n = 1, 2, … But one can have a radial flow. Elliptic Flow for only non-central collisions.

Elliptic Flow & Hydro. Calcs.

Has PHENIX found the Quark Gluon Plasma ? It is too early to say for sure, but the observation of jet suppression, indication of a very strong amount of flow etc. are very promising. The collected observations of all of the four RHIC experiments are consistent with a state of matter that has the properties of a perfect fluid comprised of quarks and gluons. fluid comprised of

Future Upgrades at RHIC Upgrade: Electron beam cooling x 10 Luminosity, longer store time PHENIX Upgrade: Si Vertex Tracking Nose Cone Calorimeter High p. T Aerogel Cerenkov Detector

Large Hadron Collider

CMS Detector

Si Preshower detector in Endcap ECAL

THANK YOU

Heavy Flavour Physics 1. Heavy flavour cross section: -->Calculable with QCD also include effects such as Shadowing -->Measure the cross section in pp, p. Pb and then extrapolate to Pb. Pb 2. Cold matter effects: --> Nuclear absorption and Comover scattering, e. g. J/psi + N --> D + D bar+ X 3. Energy loss in the medium: 4. Quarkonium suppression in QGP: When screening radius r. D < r. QQbar, at T > TD 5. Quarkonium Enhancement at LHC: No. of Q Qbar pairs produced at LHC is large. Possibility of recombination