A New Comprehensive Detector
for RHIC-II
Helen Caines
Yale University
for
The RHIC-II Comprehensive New
Detector Group
CAARI 2004 Fort Worth, Texas – Oct. 2004
Outline
 Introduction
 Why we are thinking about a new detector for RHIC-II
 Overview of the detector design
 More on specifics
 Summary
Helen Caines
CAARI 2004 – Oct. 2004
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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)
Helen Caines
CAARI 2004 – Oct. 2004
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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, g-tagged jets
 Structure and dynamics of the proton
 Large  acceptance, jets, g-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
Helen Caines
CAARI 2004 – Oct. 2004
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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
Helen Caines
CAARI 2004 – Oct. 2004
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2) How do particles acquire mass?
Hadron formation
quark coalescence?
Is chiral symmetry
restored?
♦ Contribution of gluon, sea and
valence quark to hadron mass.
♦ 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.
Helen Caines
CAARI 2004 – Oct. 2004
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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

p
e
s
g
p
W
c
c
n
D-jet
 Physics beyond the standard model
New parity violating interactions etc
Study using:
 forward W production
 g-jets and di-jets
 Heavy quarkonia and D measurements
 High ET jets
Helen Caines
CAARI 2004 – Oct. 2004
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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?
PHOBOS
ln (1/x)
low-x  forward physics
Study using:
 High y identified particles
to high pT
 Multi-particle correlations
- short & long range (D)
 4p bulk dynamics
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CAARI 2004 – Oct. 2004
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Comprehensive new detector @ RHIC-II
HCal and m-detectors
Central detector (||  3.4)
HCal and m-detectors
♦ Quarkonium physics
Superconducting coil (B = 1.3T)
Forward tracking:
2-stage Si disks
Characteristics
of detector 
♦ Jet
physics
allow
a
UNIQUE
RHIC-II
physics
program
♦ Forward low-x physics
EM Calorimeter
Forward magnet
(B = 1.5T)
♦ Global observables over 4p
♦ Spin physics
Vertex tracking
RICH
PID:
RICH
ToF
Aerogel
ToF
Aerogel
 = 1.2 – 3.5
Tracking:
Si, mini-TPC(?),
m-pad chambers
Forward spectrometer:
( = 3.5 - 4.8)
RICH
EMCal (CLEO)
HCal (HERA)
m-absorber
SLD magnet
||  1.2
6m
Helen Caines
CAARI 2004 – Oct. 2004
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Why acceptance in  & pT?
Essential for jets, high pT correlations, quarkonium, spin programs
 distributions in pp (g+jet)
Preliminary STAR results on number
correlations for pT < 2 GeV/c
Broadening in  and f pp 
pp
AA
AA
parton fragmentation modified in dense
color medium:
D elongation even on near side
can measure 40 GeV jets: 180k in 30 nb-1
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CAARI 2004 – Oct. 2004
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Need EM & hadronic calorimetry in pp
g+jet at colliders
pp (spin)
– Direct g component
– Fragmentation background
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
Helen Caines
CAARI 2004 – Oct. 2004
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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.
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CAARI 2004 – Oct. 2004
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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:
x dependence:
F
Precision Tracking + Muon Detectors
+ EMCAL + PID
Acceptance  Rates
x and cos Q* coverage
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CAARI 2004 – Oct. 2004
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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
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CAARI 2004 – Oct. 2004
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Quarkonia rates with this detector
Large acceptance for electrons and muons
||<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 )
100,000,000
10,000,000
1,000,000
New Detector
PHENIX
100,000
10,000
1,000
100
''
Y
'
Y
Y
c
X
c
X
si
'
P
si
J/
P
Comparison to LHC
?
?
10
 s(LHC)/s(RHIC) = 9 – 25
– but Ldt (RHIC) / Ldt(LHC) > 10-20
High rates + large acceptance  xF coverage, s and A scan
Helen Caines
CAARI 2004 – Oct. 2004
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Why particle ID to high-pT?
But:
Presently:
Modification of fragmentation
function is non-specific, i.e., same
for all quarks and gluons
(e.g.Gyulassy et al.,nucl-th/0302077)
Each parton contributes to
fragmentation function differently
(statistical approach (Bourelly & Soffer)).
Each expected to lose different dE in
opaque medium.
Bourelly & Soffer
Compare PID fragmentation with and without opaque medium.
Measure high pT PID two particle correlations
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CAARI 2004 – Oct. 2004
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High-pT charged particle ID (p, K, p)
2p
PID acceptance factors over upgraded RHIC detectors: f=72 (PHENIX), f=3 (STAR)
STAR, 3-4 GeV
pq,g > 10 GeV/c
pq,g > 10 GeV/c
all 
10GeV
f coverage
PHENIX
New detector, 20 GeV
4 GeV
0
|| < 0.5
-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
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CAARI 2004 – Oct. 2004
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High pT ID’d particles and jets
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CAARI 2004 – Oct. 2004
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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
Helen Caines
CAARI 2004 – Oct. 2004
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The comprehensive new RHIC-II detector
HCal and m-detectors
Central detector (||  3.4)
HCal and m-detectors
Superconducting coil (B = 1.3T)
Forward tracking:
2-stage Si disks
EM Calorimeter
Forward magnet
(B = 1.5T)
Vertex tracking
RICH
PID:
RICH
ToF
Aerogel
Helen Caines
ToF
Aerogel
 = 1.2 – 3.5
Tracking:
Si, mini-TPC(?),
m-pad chambers
Forward spectrometer:
( = 3.5 - 4.8)
RICH
EMCal (CLEO)
HCal (HERA)
m-absorber
||  1.2
CAARI 2004 – Oct. 2004
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Backup slides
Helen Caines
CAARI 2004 – Oct. 2004
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Momentum resolution
Momentum resolutions based on the tracking devices for the different regions
of pseudo-rapidity and the forward spectrometer section.
Helen Caines
CAARI 2004 – Oct. 2004
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Charged Particle PID
π/K/p ToF
A1
A1+A2+RICH
π
A1+ToF
RICH
A1+A2
K
RICH
ToF
A1+A2
p
RICH
1.
2.
3.
4.
5.
6.
7.
8.
9.
10
12.
14.
16
18.
P, GeV/c
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.
Helen Caines
CAARI 2004 – Oct. 2004
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Central tracker layout
Detector Radius(cm)
Vertex
2.8
(APS or
4.3
Hybrid pixels) 6.5
10.5
Main Si-strip 19
24.5
31
38.5
46
56
OrMain mTPC 22.5-60
High pT track 70
micropattern
115
135
170
Halflength (cm)
9.6
12
21
27
39
42
45
51
57
60
55
76
110
130
165
Sigma r-phi(cm)
Sigma z(cm) Thickness(cm)
0.001
0.001
0.01
0.003
0.03
0.03
0.012
0.035
0.2
(mylar+gas)
0 .17
0.01
0.01
0.01
0.17
0.9
1.2
1.4
0.3 G10 +
1.0 Gas +
0.05 Mylar
Position, segmentation in radius (r) and azimuthal angle (f),
and thicknesses of the various central tracking detectors.
Helen Caines
CAARI 2004 – Oct. 2004
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