A New Comprehensive Detector for RHIC-II

Outline Introduction Why we are thinking about a new detector for RHIC-II Overview of the detector design More on specifics Summary

The current group P. Steinberg, T. Ullrich (Brookhaven National Laboratory) M. Calderon (Indiana University) J. Rak (Iowa State University) S. Margetis (Kent State University) M. Lisa, D. Magestro (Ohio State University) R. Lacey (State University of New York, Stony Brook) G. Paic (UNAM Mexico) T. Nayak (VECC Calcutta) R. Bellwied, C. Pruneau, A. Rose, S. Voloshin (Wayne State University) H. Caines, A. Chikanian, E. Finch, J.W. Harris, M. Lamont, C. Markert, J. Sandweiss, N. Smirnov (Yale University)

Foundations of RHIC-II physics program Properties of sQGP (Deconfinement) Quarkonia resolution, acceptance, rates & feed-down percentages Jet and PID high pT measurements (g-jet, jet-jet) How do particles acquire mass? PID at high pT, correlations, large  acceptance, -tagged jets Structure and dynamics of the proton Large  acceptance, jets, -jets, high pT identified particles, correlations Is there another phase of matter? (CGC) High-pT identified particle yields to large  Multi-particle correlations over small & large D range

1) What are the properties of matter created? Why strongly interacting ? Initial temperatures, system evolution, EOS ? Study: via… Initial T: gg-HBT Parton density: jet tomography, flavor, intra-, inter-jet correlations Fragmentation functions: identified leading particles Deconfinement T: quarkonium states - Tdiss(Y’) < Tdiss((3S)) < Tdiss(J/Y)  Tdiss((2S)) < Tdiss((1S)) Quark vs. gluon jets: jets as f(s) and (anti) particle

2) How do particles acquire mass? Contribution of gluon, sea and valence quark to hadron mass. Hadron formation quark coalescence? Is chiral symmetry restored? Modifications (quenching) in excited vacuum. Mass modifications due to excited vacuum states, effects of chiral symmetry? Study via: Modification in jet fragmentation Identified hadrons at high pT in fragmentation of jets in pp and AA.

3) Dynamical structure of proton How do gluons, sea quarks, orbital angular momentum contribute to spin of proton? Transversity Transversity dist. function of q andq Sivers effect  ST  (P  k)  0 Physics beyond the standard model New parity violating interactions etc p  s c c g W e n D-jet Study using: forward W production g-jets and di-jets Heavy quarkonia and D measurements High ET jets

4) Is there another phase (CGC) at low-x? Gluon saturation and color glass condensate. What are its features ? How does it evolve into the QGP? ln (1/x) PHOBOS low-x  forward physics Study using: High y identified particles to high pT Multi-particle correlations - short & long range (D) 4p bulk dynamics Dima email – Mueller Navelet Dijets

Comprehensive new detector @ RHIC-II HCal and m-detectors Superconducting coil (B = 1.3T) Vertex tracking RICH Aerogel EM Calorimeter ToF Tracking: Si, mini-TPC(?), m-pad chambers PID: Forward tracking: 2-stage Si disks Forward magnet (B = 1.5T) Forward spectrometer: (h = 3.5 - 4.8) EMCal (CLEO) HCal (HERA) m-absorber |h|  1.2 h = 1.2 – 3.5 Central detector (|h|  3.4) Quarkonium physics Jet physics Forward low-x physics Global observables over 4p Spin physics Characteristics of detector  allow a UNIQUE RHIC-II physics program SLD magnet 6m

Why acceptance in  & pT? Broadening in h and f pp  AA pp AA Essential for jets, high pT correlations, quarkonium, spin programs h distributions in pp (g+jet) Preliminary STAR results on number correlations for pT < 2 GeV/c Broadening in h and f pp  AA pp AA parton fragmentation modified in dense color medium: Dh elongation even on near side can measure 40 GeV jets: 180k in 30 nb-1

Need EM & hadronic calorimetry in pp g+jet at colliders Direct g component Fragmentation background pp (spin) isolation cuts Ehad < e Eg in cone requires HCAL (see CDF) e+e- in SLD Hermetic detector (4p HCAL)  missing energy W production: W  e(m) + n (Nadolsky, Yuan, NPB666 31), W  jet + jet

EM and hadronic calorimetry in AA Isolation cuts not effective (background)  go to high ETg  requires high rate, large acceptance g+jet at high ETg for ETg = 20 GeV  19,000 g + jet events in 30 nb-1 (1000 @ 30 GeV) with high pT PID over full away-side acceptance ||<3.4 Hadronic calorimetry - in general improves jet energy resolution (neutral component). removes trigger bias of EMC. proven essential in all HEP detectors for jet physics. not available in any RHIC experiment.

Quarkonia reconstruction Melting T’s  Suppression Tmelt(Y’) < Tmelt((3S)) < Tmelt(J/Y)  Tmelt((2S)) < TRHIC < Tmelt((1S))? Production and nuclear absorption/shadowing studies Resolution: Precision Tracking + Muon Detectors + EMCAL + PID Acceptance  Rates x and cos Q* coverage xF dependence:

Charmonium cc feed-down To measure cc decay & determine feed-down to J/y cc  J/y + g, must have large forward acceptance for g

Quarkonia rates with this detector Large acceptance for electrons and muons |h|<3, Df = 2p Precision Tracking + Muon Detectors + ECAL + PID Au+Au min bias: 30 nb-1 plepton > 2 GeV/c for J/Y (4 GeV/c for ) Comparison to LHC s(LHC)/s(RHIC) = 9 – 25 but Ldt (RHIC) / Ldt(LHC) > 10-20 High rates + large acceptance  xF coverage, s and A scan Eg > 2 GeV Eg > 4 GeV ? BAR chart …

Why particle ID to high-pT? But: Each parton contributes to fragmentation function differently (statistical approach (Bourelly & Soffer)). Each expected to lose different dE in opaque medium. Presently: Modification of fragmentation function is non-specific, i.e., same for all quarks and gluons (e.g.Gyulassy et al.,nucl-th/0302077) Bourelly & Soffer Compare PID fragmentation with and without opaque medium. Measure high pT PID two particle correlations

High-pT charged particle ID (p, K, p) PID acceptance factors over upgraded RHIC detectors: f=72 (PHENIX), f=3 (STAR) |h| < 0.5 pq,g > 10 GeV/c New detector, 20 GeV pq,g > 10 GeV/c all h STAR, 3-4 GeV 10GeV PHENIX 0 f coverage 2p 4 GeV -3 -2 -1 0 1 2 3 rapidity Multiply pp events by factor of ~ 8 x 1015 for AuAu events in 30 nb-1 RHIC year

High pT ID’d particles and jets

Summary The New Comprehensive Detector designed for the new era of UNIQUE physics at RHIC-II : High rates Large acceptance High pT tracking PID out to high pT PID in the forward direction Good momentum resolution Jet/leading particle physics Quarkonium physics Structure and dynamics of the proton Low-x physics New (as yet) undetermined physics

The comprehensive new RHIC-II detector HCal and m-detectors Superconducting coil (B = 1.3T) Vertex tracking RICH Aerogel EM Calorimeter ToF Tracking: Si, mini-TPC(?), m-pad chambers PID: Forward tracking: 2-stage Si disks Forward magnet (B = 1.5T) Forward spectrometer: (h = 3.5 - 4.8) EMCal (CLEO) HCal (HERA) m-absorber |h|  1.2 h = 1.2 – 3.5 Central detector (|h|  3.4)

Backup slides

Momentum resolution Momentum resolutions based on the tracking devices for the different regions of pseudo-rapidity and the forward spectrometer section.

Charged Particle PID Charged hadron particle identification as a function of momentum using the ToF (time-of-flight), Aerogel 1 (n =1.01), Aerogel 2 (n =1.05), and gas-RICH (n=1.00175) detectors. The horizontal lines indicate where each particle can be identified based on combinations of signals.

Central tracker layout Detector Radius(cm) Halflength (cm) Sigma r-phi(cm) Sigma z(cm) Thickness(cm) Vertex 2.8 9.6 0.001 0.001 0.01 (APS or 4.3 12 Hybrid pixels) 6.5 21 10.5 27 Main Si-strip 19 39 0.003 0.03 0.03 24.5 42 31 45 38.5 51 46 57 56 60 OrMain mTPC 22.5-60 55 0.012 0.035 0.2 (mylar+gas) High pT track 70 76 0 .17 0.17 micropattern 115 110 0.01 0.9 0.3 G10 + 135 130 0.01 1.2 1.0 Gas + 170 165 0.01 1.4 0.05 Mylar Position, segmentation in radius (r) and azimuthal angle (f), and thicknesses of the various central tracking detectors.