heavy ion tea, lbnl, berkeley ca, 4/27/04comprehensive rhic ii detector john harris (yale) a...

Heavy Ion Tea, LBNL, Berkeley CA, 4/27/04Comprehensive RHIC II Detector

John Harris (Yale)

A Comprehensive New Detector for RHIC II Physics

for

L. Bland, M. Calderon, P. Steinberg, T. Ullrich (BNL)

H. Caines, J.W. Harris, C. Markert, N. Smirnov (Yale)

R. Bellwied, C. Pruneau, S. Voloshin (Wayne State)

M. Lisa, D. Magestro (Ohio State)

B. Surrow (MIT)

R. Lacey (Stony Brook)

S. Margetis (Kent State)

G. Paic (UNAM Mexico)

T. Nayak (VECC Calcutta)(forming) an “exploratory working group” on a comprehensive new

detector for RHIC II physics

…. (LBNL)?

presented at RHIC Planning Meetingpresented at RHIC Planning MeetingBNL on 4 Dec 2003BNL on 4 Dec 2003

Comprehensive RHIC II DetectorComprehensive RHIC II Detector

Ideas for a Ideas for a Comprehensive New DetectorComprehensive New Detector for for In-Depth Study of the In-Depth Study of the QGPQGP, , Initial ConditionsInitial Conditions

and and Spin PhysicsSpin Physics at RHIC II at RHIC II

R. Bellwied, J.W. Harris, N. Smirnov, R. Bellwied, J.W. Harris, N. Smirnov, P. Steinberg, B. Surrow, and T. UllrichP. Steinberg, B. Surrow, and T. Ullrich

Statement of Interest document and Yale Workshop (April 16-17, 2004)at

http://star.physics.yale.edu/users/harris/


PHOBOS BRAHMS

Relativistic Heavy Ion Collider Facility

RHIC AuAu Design Parameters:Beam Energy = 100 GeV/u No. Bunches = 57 No. Ions /Bunch = 1 109

Tstore = 10 hours

Lave = 2 1026 cm-2 sec-1

RHIC

AGS

LINACBOOSTER

TANDEMS

Pol. Proton Source

High Int. Proton Source9 GeV/uQ = +79

1 MeV/uQ = +32

HEP/NP

g-2

U-lineBAF (NASA)

STARPHENIX

RHIC II AuAu Parameters:Beam Energy = 100 GeV/u No. Bunches = 112 Lave = 8 1027 cm-2 sec-1

RHIC II pp Parameters:Beam Energy = 250 GeV/u Lave = 5 1032 cm-2 sec-1

RHIC pp Design Parameters:Beam Energy = 250 GeV/u Lave = 1.5 1032 cm-2 sec-1


Luminosities for AuAu at RHIC & PbPb at LHC

L dt (nb-

1)

RHIC

2x1026 8x1026L (cm-2s-1)

RHIC: 14 weeks production/yr, 4 experiments

LHC: 4 weeks production/yr, 2-3 experimentsDesign L by third year

LHC

8x1026

RHIC II: 14 weeks production/yr

RHIC II ?

8x1027

L dt (RHIC II) = 35 L dt (LHC)

eRHIC / EIC (?)


Questions about RHIC II

• Is there compelling physics at RHIC II (with LHC)?

• How to harvest effectively this physics? – Evaluate experimental capabilities / detector complement at RHIC II?– Funding (upgrades, R&D, new detectors)?

• Finally, how to convince colleagues outside the field? – Long-term competition and NSAC Long Range Plan (2006)?

• Other physics / questions?– Identify them and best solutions……..(just starting)


A Start at Addressing Questions about RHIC II

Compelling physics at RHIC II!– Identify in detail properties of the QGP

(as a function of multiple variables)• Parton tomography of the QGP• Melting of the “Onium” States [J/, ’, Y(1s), Y(2s), Y(3s)]• Collective flow effects• Fluctuations (parity violation)?• Two-photon HBT to determine the temperature of the QGP• Others

– Establish the initial conditions at low x (forward rapidities)• Saturation / color glass condensate

– Determine structure and dynamics of the proton• Rare processes: sea polarization, parity-violating processes

– Investigate details of QCD – exotic hadrons, glueballs• 5-quarks, glueballs, others…..

– Exotic or new effects?– Others?


How to Harvest this Physics?• Utilize hard probes / large (pT, y) acceptance

– Jets

– High-pT PID particles

– -high-pT correlations

– e+e-,+ pairs for J/, Y(1s), Y(2s), Y(3s)– e, determination for W decays– Detailed low-x forward coverage (tracking, calorimetry)

• General Detector Requirements– ~4 EM + hadronic calorimetry (includes detailed forward coverage)– high resolution tracking (in large Bdl and forward)– PID to p ~ 20-30 GeV/c (flavor tagging)– high rate DAQ and specialized triggering

• Experimental Approach & Possible Solution– Utilize (to extent possible) existing High Energy Magnet/components

• e.g. SLD, CDF, D0, H1, …..– Build “smart”, fast, state-of-art detector components


d+Au RCP at forward rapidities

pT [GeV/c]

RC

P • Au-side RCP almost no variation with centrality

• d-side RCP interesting - central is most suppressed

L.Barnby, STAR QM’04

STAR Preliminary FTPC

Au-side

d-side

cen

tral


d

Au

Phenix Preliminary

Hadrons


dAu

Phenix Preliminary

Hadrons


dAu

Shadowing?Cronin effect &anti-shadowing?

Stopped Hadrons!

Phenix Preliminary


Predictions from Theory for dAu and pAu

Hard Scattering: I. Vitev nucl-th/0302002 v2

Y=0

Y=3

Y= -3

CGC at y=0

Very high energy

As y grows

Color Glass Condensate

D. Kharzeev et al., PR D68:094013,2003


Nuclear modifications in dAu at = 3.2!

RHI Physics at RHIC (II) in an LHC-era

Saturation at low x (10-3)?

RHIC in unique region!

ycm final state effects

forward initial state

HERA RHIC LHC eRHIC

BRAHMS, R. Debbe (QM-2004)

PRL 91 072305 (2003)

LHC ions saturated (ycm)?

LHC ycm

RHIC ycm

RHIC forward


• Measure QGP Properties & Shadowing/Saturation/CGC (low-x forward physics) with Hard Probes – some examples:

– Measure modification of FF’s as parton traverses QGP via

• jets, photons, high-pT identified particles

– Measure initial conditions (saturation) vs final state (parton E-loss) effects

• x-dependence – compare pA, AA, forward- vs mid-rapidities

– Determine initial energy of the parton scattering for accurate E-loss via

• Photon-tag on opposite side (rates are low)

– Measure flavor-dependence of jet quenching via

• -jet, -leading hadron, di-hadrons, di-jets (even lower rates)

• displaced vertices for D- and B-decays (reduced E-loss for heavy quarks)

– Measure deconfinement via melting of the Y(1s), Y(2s) and Y(3s) states

• e and identification

– Collective flow (effects on every observable, time evolution)

– Fluctuations (parity violation, always new ideas)?

– Two-photon HBT to determine photon spectrum & temperature of the QGP

Interesting RHI Physics at RHIC II


• Measure Polarization in Proton and Rare Processes with Hard

Probes:

– Heavy flavor production (polarized and unpolarized gluon distn’s)

– Jet physics (for polarization in proton)

– Electro-weak Physics (W+, W- decays for polarization of QCD sea)

– Physics beyond the Standard Model (parity-violating interactions)

• Understanding Details of Strong Interactions (QCD)

some examples in pp collisions (possibly AA):

– Measure “composite” particle spectrum (pentaquarks, glueballs?) in 1–3 GeV

mass range

• High statistics 2-, 3-, 4-particle correlations with PID in pT range up to 5

GeV/c and forward to large pseudo-rapidity

• Missing mass and energy measurements as well as quantum numbers

(very forward)

– Further search for the H di-baryon

Interesting Polarized and Unpolarized pp Physics at RHIC II


Detailed Study of the QGP and Initial Conditions

FQGP (gQGP) = finitial (√s, A1+A2, b, x1, x2, Q2)

fQGP (pT,y , ,pT

jet,y jet ,jet,flavor jet, flow)

• Probes

– Jets

– High pT identified (light-, s-, c-, b-quark) particles

– photons

– -jet, - high-pT identified particle, particle-particle, di-jets

• Use Hard Probes over Multi-Parameter Space:

– Energy - √s

– Geometry - system A1+A2 , impact parameter b

– Rapidity (x-dependence) to forward angles

– Transverse momentum of jet / leading particle

– Particle type (flavor)

– Orientation relative to flow plane ( flow)

– Photon-tag on opposite side


Detailed “Tomography” of the QGP

/parton

parton

flow plane

FQGP (gQGP) = finitial (√s, A1+A2, b, x1, x2, Q2)

fQGP (pT,y , ,pT

jet,y jet ,jet,flavor jet, flow)

Detailed QGP “Tomography”

parton

parton

parton parton

par

ton

parto

n

parton parton, parton parton

parton

parton

jet

leading particle

(light-, s-, c-, b-quark)

jet

jet

leading particle


leading particle


parton

parton


Modification of Fragmentation Function

Induced Gluon Radiation• Softens fragmentation

in je

i j t

t

n e

: increases

z : decreases

chn

Gyulassy et al., nucl-th/0302077


Gyulassy RHIC II Workshop (4/16/04) Talk

Two main jet physics categories for new detector

• Global medium modification measurements based on rate, tracking hermiticity and complete calorimetry (add: Gamma-jet and forward jet measurements)

• Determine jet energy and particle distribution with and without medium modification

• Determine gluon vs. quark jet distributions and medium modifications

• Specific medium modifications measurements based on particle identification, rate, hermiticity and completeness of jet (add: Identified leading and associated particles, full jet measurments in terms of energy and pid).

• Heavy quark energy loss through R(AA) and rapidity distribution• Decouple effects of PDF and FF medium modifications based on

identified particle distributions inside the jet.• Determine energy loss mechanism from medium modification to

different flavor partons• Determine radiative vs. collisional energy loss as a function of jet

characteristics

R. Bellwied, RHIC II Workshop

• We might push the envelope on the ‘reference system’, i.e. our measurements in the pp system will replace many basic jet property measurements by adding particle identification and coverage to the original measurements.

– New insight in the relative importance of PDF and FF to the final state particle distribution.

– New insight into the origin of the spin of the nucleon– New insight into gluon vs. valence quark vs. sea quark PDF– New insight into the parton to hadron fragmentation functions based on better pid

measurements

• Bottomline: The goal is to characterize the features of in-medium QCD compared to in-vacuum QCD. Along the way we learn about the medium and we learn about fragmentation and hadronization. This program is complementary to the LHC main physics goals.

…and let’s not forget…


• Long range vs. short range gluon radiation

• Quark jet vs. gluon jet medium modification

• Impact of flavor dependence of parton distribution on medium modification

• Understanding leading particle asymmetries and their modifications

• Modifications to identified particle correlations in jet

• Different medium modifications to different particle fragmentation functions? Are heavy quarks different in medium than light quarks?

Fundamental questions of in-medium vs. vacuum QCD properties that can be answered with specific jet measurements


Question: do heavy quarks (charm, bottom) lose energy similar to light quarks ? Dead cone effect ?

Example: Heavy Quark Energy Loss

• Exclusive jet tagging:

– High- pT lepton (B→Dl) &

displaced vertex

– Hadronic decay (ex.D0 K-+) &

displaced vertex

• Ratio D/hadrons (or D/0)

enhanced and sensitive to

medium properties.

tpp

tAA

collAA dpdN

dpdN

NR

/

/1


Nuclear modification of heavy quark fragmentation function (e.g. nucl-th/0205064)



Flavor-tagged Phenomena• Strange and charmed hadron/antihadron asymmetry

– Leading particle effect (e.g. E791, hep-ex/0009016)

• Intra-jet strange hadron production

– Difference in gluon and quark jets (e.g. OPAL, hep-ex/9805025)

• Fragmentation function parametrizations for heavy hadrons

– Flavor quenching, dead cone effects (e.g. hep-ph/0106202)

• Additional production mechanisms for s,c,b hadrons

– Recombination or gluon radiation (e.g. nucl-th/0306027)

• Transverse and longitudinal polarization

– Disappearance in AA (e.g. nucl-th/0110027)

General Jet Phenomena• Rapidity gaps between jets

– Difference between quark and gluon jets (e.g. hep-ph/9911240)

• Jet like contributions outside the jet cone (pp, pA, AA)

– ‘pedestal effect’, small vs. large angle gluon radiation

(e.g. Stewart, PRD42 (1990) 1385, hep-ph/0303121)

Measure Other Modifications in pp vs pA vs AA


• PYTHIA prediction agrees well with the inclusive 0 cross section at 3-4

• Dominant sources of large xF production from:

• q + g q + g (22) + X

• q + g q + g + g (23) + X

g+g and

q+g q+g+g

q+g

Soft processes

PYTHIA: a guide to the physics (L. Bland, RHICII Workshop 4/17/04)Forward Inclusive Cross-Section: Subprocesses involved:

q

gg

q g

STAR FPD


• Relativistic Heavy Ions– Jets, high pT leading particles:

• Excellent p/p up to pT = 40 GeV/c (ycm)• Electromagnetic / hadronic calorimetry over ~4 phase space• Particle identification out to high pT (p ~ 20-30 GeV/c) • hadron (,K,p) and lepton (e/h, /h) separation central and forward

– Flavor dependence: • Precision vertex tracking (displaced vertices c/b-decays)

– Onium: • Large solid angle coverage for e and

High rate (40kHz) detectors, readout, DAQ, trigger capabilities.

Detector Requirements from RHI Physics


• Spin (polarized pp)– Heavy Quark Production (gluon polarization): e, detection

open beauty production as probe of gluon polarization

leading order diagram for heavy quark production in gg-fusion:

– QCD (especially jet physics, gluon polarization):

jet reconstruction (EM + hadron calorimetry)

single-photon detection (/πo separation), b/c-tagging

leading order diagrams for gluon-initiated jets:

– Electroweak Physics (QCD sea polarization via W):

W e, + X requires forward e and detection,

no away-side jet

e, triggers

large forward acceptance

– Physics beyond the Standard Model (parity violating processes):

e and detection, jet reconstruction, b/c-tagging, missing energy

Detector Requirements from Spin Physics


• Full acceptance in barrel and forward/backward region (0 < || < 3-4) – Tracking

– High-rate capabilites (pixel, silicon and GEM-type detectors)– Precision inner vertex detector system - secondary vertex

reconstruction, momentum resolution– Large Bdl, B ~ 1.5 T over 2 m.

– Particle Identification– , K, p to ~20-30 GeV/c– precision inner vertex detector system - secondary vertex

reconstruction, momentum resolution– Electromagnetic and hadronic energy

– transverse and longitudinal tower segmentation (for jet reconstruction and electron/hadron separation).

• Specialized calorimeter / tracking beyond ||~4 at small x for Emissing

• system in barrel and forward/backward region for heavy flavors• Large Bdl, B ~ 1.5 T over 2 m.• Precise relative luminosity measurement at high-rates • Local polarimeter & absolute luminosity measurement• High rate DAQ, triggering for rare processes, secondary-vertex trigger

Detector Specification


• Re-cycle existing equipment– Utilize detector components from other collider experiments that are

decommissioned, or will be in the near future, e.g. SLD, CDF, D0, CLEO– Should be possible to identify and procure existing high field magnet and a

large amount of electromagnetic and/or hadronic calorimetry.

• Build new fast detectors, electronics, DAQ, triggers– New technologies, tracking, PID, electronics, DAQ, triggering

Our Approach

CDF D0 CLEO ALEPH SLD

Magnet 1.4T,SC 2.0T,SC 1.5T,SC 1.5T,SC 1.5T-upg-SC

R in m 1.5 0.55 1.45 2.48 2.8

L in m 4.8 2.7 3.5 7.0 7.0

Bdl 2.1 1.0 2.0 3.75 4.2

HCal Fe/Sc, 0.78/√E

LiquidAr, 0.62/√E

No FET str tube 0.65/√E

FET str tube 0.85/√E

EMC Pb/Sc, 0.13/√E

LiquidAr, 0.15/√E

CsI crys, 0.03/√E

Pb/W, 0.18/√E

LiquidAr, 0.15/√E

detector yes yes yes yes yes

Decommis-sioned ?

2009 2007-09 2007 yes yes

Y

X R = 2.8 m

SLD magnet, hadronic cal. + -chambers || < 3 (depth = 15 x (5 + 5) cm, r = 0.3 cm, z = 3 cm)

π/K/p (1-30 GeV/c) PID: Gas RICH (C5F12) with Spherical Mirror Read-out: CsI pads sensitive to UV and MIP

AeroGel Cherenkov Detectors with two values of N

SC Magnet Coil, 1.5 T

EMC: Crystals + Fe(Pb)/Sc (accordion type, projective) or LAr 6x6 mrad towers

Additional Tracking: Si Vertex, 4 Pad Detectors in Barrel and End Caps (-pattern) Si + Pad Detectors Forward

dZ = 3.0 m

3-6 layers Si-strip detectors or mini-TPC

ToF RPC’s

R =

2.8

m

A Proof of Principle

Comprehensive RHIC II Detector

Detector Coverage

1. 2. 3. 4. 5. 6. 7. 8. 9. 10 12. 14. 16 18.

p (GeV/c)

A1+ToF A1+A2+RICHRICH

ToF

PID (, K, p)

Calorimetry & μ-detector: -3 < η < +3

Tracking: -3 < η < 4.5

PID: = -1.2 < η < 3


Tracking Detectors under ConsiderationTracking Detectors in Barrel Simulation Detector R position half-length Sigma-r Sigma-Z Thickness

(cm) (cm) (cm) (cm) (cm)Vertex detector[1]1. APS 1 2.8 9.6 0.001 0.001 0.02 or 2 4.3 12. Si Pixel 3 6.5 21. 4 10.5 27.

Main tracker 2a. Si strip 1 19. 39. 0.003 0.03 0.03 2-sided 2 24.5 42. 3. 31. 45. 4. 38.5 51. 5. 46. 57. 6. 56. 60. or

2b. miniTPC 22.5 – 60. 55. 0.012 0.035 0.2 Mylar + Gas (35 pad rows with 0.2x0.8 pad size)

High pT tracker

3. Micro-pattern pad detector 1. 70. 76. 0.17 0.17 0.3 G10 + 2. 115. 110. 0.01 0.9 1.Gas + 3. 135. 130. 0.01 1.2 0.05 Mylar 4. 170. 165. 0.01 1.4

[1] Only two vertex detector layers were used in the track reconstruction of this simulation. These were Si pixels of 20100 m2 size at 6.5 and 10.5 cm radii.

What is needed to extend forward What is needed to extend forward measurements significantlymeasurements significantly

• Extend pt reach to ~6 GeV/c for inclusive spectra.

• Kinematic limit restricts such measurements to ~2-3.5

• Momenta and PID determination in range of 20-60 GeV/c

Videbaek – Yale RHIC II Workshop 4/16/04

GEANT simulation was started for the “SLD-like” set upAll materials and detector resolution parameters:

“reasonable and conservative”

N. Smirnov, RHIC II Physics and Perspectives for a New Comprehensive Detector Workshop

Solenoid with Bz = 1.5T; {toroidal field, lamp-shape field, …}

6 planes Si tracker

CalorimeterR

Z

Y

X+/-3.5 m

1.6 m

μ-detector

η = 1.

η = 2.

η = 3.45

η = 4.2

R = 3. mBz = 1.5 T


Momentum Resolution

dPt/Pt, %

dPt/Pt, %dPt/Pt, %

Pt, GeV/c

Pt, GeV/c

dPt/Pt, %

Pt, GeV/c

IηI < 0.8 0.8<IηI < 1.6

IηI > 2.2

IηI

Pt = 10. GeV/c

Pt = 2. GeV/c

5. 10. 20. 30. 5. 10. 20. 30.

2. 4. 8. 12.

10 10

10

1 1

10

40

40

1 2 3

Pad detectors only

all tracking detectors


• Detector parameters to consider:– Particle identification (PID) reach in momentum– Pseudo-rapidity coverage– Detector resolutions: momentum, energy, two-track– Data acquisition (DAQ) rate

• A new comprehensive detector would be superior to:– Upgraded STAR in terms of resolution, PID, coverage (inc.

calorimetry), rate– Upgraded PHENIX in terms of PID, coverage (inc. calorimetry)– ALICE in terms of PID, coverage, resolution, statistics/operation

(pp, pA?, AA)– CMS in terms of PID, statistics/operation (pp, pA?, AA)

Detector Parameter Considerations for Detector Comparisons


Fast tracking detectors complement fast PID, calorimetry– 40x improvement in DAQ rate compared to STAR

High resolution EM calorimeter and chambers– allows resolution of all Y states

Near 4 coverage in tracking, PID, calorimetry– 20x improvement in heavy quark probes compared to PHENIX

(> 20,000 Y per RHIC year, and still > 3000 Y(3s))

PID out to 20-30 GeV/c over ~4 with high two-track resolution tracking– Measure actual jet physics rather than leading particle physics

• Particle identify all particles in jet

• Measure intra-jet correlations between identified hadrons in jet

– Direct heavy flavor tagging of jets via leading particle reconstruction

-jet measurements with away-side spectrum out to 20 GeV/c

(20 weeks at 40Lo)

– pT = 10 GeV/c 2.6 M events - pT = 15 GeV/c 260 K events

– pT = 20 GeV/c 30 K events

Various Aspects of Detector Extend the Physics Reach


Quarkonium Measurements at RHIC• AA

– Goal: suppression as a signature of deconfinement in a QGP– Thermometer for early stages:

Tdis(’) < Tdis((3S)) < Tdis(J/) Tdis((2S)) < Tdis((1S))

• pp– Interesting in its own right

• no nuclear effects (production pure)• close s gap (fixed target CDF,D0)

– baseline for pA, AA– Spin: G via J/

• pA– necessary to understand nuclear effects

• xF, x1, x2 dependence

– Rates for rare processes increases by A compared to pp


Quarkonium Measurements at RHIC

• Decay modes: 1S, 2S), (1S, 2S) ℓ ℓ

cJ/b

• – clean trigger– experiments have usually higher statistics than ee

– not the best when low pT is important

• ee

– trigger hard for J/ (no problem for )– larger background than

Requirements for 3rd Generation Detector

High Rate

Large acceptance rate + xF coverage

Pythia 6.2 Pythia 6.2

Requirements for 3rd Generation Detector

J/ measurements require:highly granular E.M Calorimeter at least at mid-

rapidityprobably only feasible in pp, pA, peripheral AA

need simulations here large acceptance

Reduce hadronic background high e/h possible with good calorimetry and PID up to

10-20 GeV/c situation better for muons anyhow

Good measure of reaction planeeasy with ZDC+SMD

T. Ullrich, RHIC II Workshop 4/16/04

Rates at RHIC-II

Assume here: large acceptance (||<3) one channel only (e+eor ) RHIC-II:

L = 5·1032 cm-2 s-1 (pp) L = 7-9·1027 cm-2 s-1 = 7-9 mb-1 s-1 (AuAu) hadr. min bias: 7200 mb 8 mb-1 s-1 = 58 kHz 30 weeks, 50% efficiency Ldt = 80 nb-1

100% reconstruction efficiency

AA = pp (AB)


Rates at RHIC-II Au+Au min bias rates

R(J/) = 27 Hz R(’) = 1 Hz R((1S)) = 0.01701 Hz R((2S)) = 0.00297 Hz R((3S)) = 0.00324 Hz

Au+Au, 30 weeks50% efficiency 2.7·108 J/ 1·107 ’ 170100 (1S) 29700 (2S) 32400 (3S)

pp lose factor (AB) gain Lpp/LAA ~ 60,000


e+e-(1S)

(2S)

full scale simulation / reconstruction

(3S)


Need Open Charm Measurement

SPSs = 17 GeV RHIC

s = 200 GeV

At RHIC open charm production provides reference and is perhaps the only way to understand charmonium suppression (same gluon conditions in the initial stage)


Quarkonia Summary In terms of quarkonia physics RHIC-II is not too far behind LHC

(LHC)/(RHIC) = 9 (GRV-HO) – 25 (MRS-D1) RHIC-II: 5 higher L RHIC: > 5 times longer running

T. Ullrich, Yale Workshop 4/2004

Measuring “just” J/ is not enough to extract a physically meaningful result

AA, pp, pA as function of pT, xF, centrality, reaction plane

A 3rd generation detector and RHIC-II luminosity provide a world class measurement in pp, pA, AA

Sufficient statistics to allow the study of production vs. pT, xF, centrality, reaction plane

Quarkonia in polarized pp might open a whole new opportunity unique to RHIC (I know too little about it for this talk)


Forward Physics at RHIC-II

in p+p (transverse & longitudinal) and p(d)+nucleus

• ‘hard scattering’ particle correlations spanning large rapidity difference

o flavor tagging of partonic scattering

o longitudinal/transverse spin effects, selected on Bjorken x values of colliding partons

o probe rapidity dependence of saturation scale

• Large rapidity Drell-Yan (electroweak probes)

o quantify Sivers function (parton orbital angular momentum in proton)

o probe gluon saturation

from Les Bland Talk at RHIC II Workshop 4/16/04

p+p (200 GeV) X + W+/- e(μ)+/- + ν

A B

A

A

B

B

Pt, GeV/c

Rapidity

dPt/Pt

dPt/Pt

{e+}

{μ+}


40

20

20

10

0 1 1 2

Sigma of dPt/Pt ~3.% ~6.% in a case p+p (500 GeV)

PYTHIA event generator

Case A: |η| < 1.2Case B: |η| = 1.2 - 2.4

– HBT possibilityThere is space to install a few miniTPCs ( 15 pad rows, 0.2x0.8 cm² pad size, 45 cm maximum drift distance) with a ~1. X0 photon convertor in a front (removable).

A: GEANT & TPC response & reconstruction. B: & Eloss, scattering C: & all EM interactions

Y

X

A B C

~0.3 deg ~0.5 deg

photon angle resolution dS/R



What we still need to know

Is the produced matter a thermalized Quark-Gluon Plasma? If yes, what are its properties ?

Confirm that the observed high pT suppression is indeed due to the parton radiative energy loss

Study the dependence on the quark mass; induced QCD radiation is suppressed for heavy quarks (“dead cone” effect in the medium) => smaller quenching for the

charm/beauty jets; different jet shapes

Kharzeev, Yale Workshop 4/2004

Are effects observed at forward rapidity due to parton saturation in the CGC?

Back-to-back correlations for jets separated by several units of rapidity are very sensitive to the evolution effects (A.H.Mueller,H.Navelet, ’87) & to the presence of CGC (DK, E.Levin,L.McLerran, hep-ph/0403271)

Open charm, dileptons, photons (DK, K.Tuchin, hep-ph/0310..) in the forward region


What else is interesting at RHIC II

Diffractive production, especially double diffractive production at central rapidity very intriguing effects observed at CERN, (WA102 ‘97, F. Close, A. Kirk, hep-ph/9701222) possibly related to QCD anomalies: (J. Ellis, DK, hep-ph/9811222) (E. Shuryak and I. Zahed, hep-ph/0302231)

use A and Z dependence of the production cross sections to discriminate between (mostly) glueball and quark states!

Kharzeev, Yale Workshop 4/2004

Spin physics: access the sea polarization by looking at the target fragmentation region

difficult in fixed target expts, but very interesting effects (e.g., strong L polarization in n DIS) have been observed (WA59, …)

and related to the sea quark polarization: (J. Ellis, DK, A. Kotzinian, hep-ph/9506280; … )

these studies can give information on the spin correlations of partons in the nucleon


M. Gyulassy (nucl-th/0403032)


Gyulassy RHIC II Workshop (4/16/04) Talk


• Unique physics at RHIC II complementary with LHC– Detailed QGP tomography

– Fragmentation in-medium and in vacuum for light and heavy quarks, gluons

– Onium suppression

– Saturation vs. CGC

– Rare processes in spin physics

– Other? - must still develop this case!

• Comprehensive new detector system can harvest this physics– Proof of principle (full x, and pT range for all flavors)

– Maximize physics output from RHIC II – must still develop this case!

• Detailed simulations to optimize detector configuration– continuing!

• Forming exploratory working group!• Interest in community (to be developed!)

– Next generation of RHI physics in U.S.

– More theoretical input / guidance

– Experimental interest?

– Comments

Summary

presented at RHIC Planning Meetingpresented at RHIC Planning MeetingBNL on 4 Dec 2003BNL on 4 Dec 2003

Comprehensive RHIC II DetectorComprehensive RHIC II Detector

Ideas for a Ideas for a Comprehensive New DetectorComprehensive New Detector for for In-Depth Study of the In-Depth Study of the QGPQGP, , Initial ConditionsInitial Conditions

and and Spin PhysicsSpin Physics at RHIC II at RHIC II

R. Bellwied, J.W. Harris, N. Smirnov, R. Bellwied, J.W. Harris, N. Smirnov, P. Steinberg, B. Surrow, and T. UllrichP. Steinberg, B. Surrow, and T. Ullrich

Statement of Interest document and Yale Workshop (April 16-17, 2004)at

http://star.physics.yale.edu/users/harris/

heavy ion tea, lbnl, berkeley ca, 4/27/04comprehensive rhic ii detector john harris (yale) a...

Documents

dt rhic

rhic iicompelling physics

rhic iiis

rhic pbpb

rhic iir

physics questions

rhic pp design parameters

comprehensive new detector