Download Future projects: A Muon Telescope Detector (MTD) for STAR

A Muon Telescope Detector (MTD) for STAR:
A new opportunity to build on the outstanding success of the joint
U.S.-China collaboration on the STAR TOF project
T.Hallman
STAR TOF Workshop, April 27- 28, 2009
Hangzhou, China
TJH, TOF Workshop Hangzhou April 2009
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A Muon Telescope Detector (MTD) for STAR
Outline:
•
Motivation and introduction
•
Simulation
•
The R&D results for the MTD
•
Performance of a prototype MTD at STAR
•
Physics perspectives with full coverage
•
Conclusions
TJH, TOF Workshop Hangzhou April 2009
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S. Bass
Physics Goals at RHIC
LGT
IdentifyCYM
and& study
the properties of matter with partonic degrees of freedom
(flavor, color, sound, temperature
…)
hadronization
PCM & clust.
Penetrating probes
Bulk
NFD probes
NFD & hadronic TM
- “jets” and heavy flavor
Electromagnetic probes:
- v2  partonic collectivity
TM
hadronicratios.
string
- spectra at low
pT&, particle
PCM & hadronic TM
(,e+e-)  chiral symmetry
- vector meson properties
- thermal dileptons and photons  TQGP
- quarkonia (J/e+e-)  color screening
TJH, TOF Workshop Hangzhou April 2009
restoration
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What has been discovered so far:
T ~ 200-400 MeV, i  30-60 0 examined in the
laboratory
The hottest, densest matter yet
It is highly opaque to colored
probes– quarks and gluons –
but not to photons
S 
4 
3T s
It flows as a relativistic quantum
liquid with minimal shear viscosity
Pedestal&flow subtracted
It produces copious mesons and
baryons with yield ratios and flow
properties that suggest their formation
via coalescence of valence quarks
from a hot thermal bath.
figure by D. d’Enterria
S = sound attenuation length
FluidQuasiParticlesHadrons
(~ mean free path)
Evidence for fluid breaking up into quasiFor reasonable T (~ 2TC ) and 
particles
with quantum numbers of quarks
(~ 1 fm/c) data suggest /s << 0.3
before hadrons
These observations prove that a new state of matter has been created
TJH, TOF Workshop Hangzhou April 2009
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A next big step for RHIC:
• Discovering the spectra and dynamics in the
charm sector:
– One major upgrade with this physics as a prime focus is the
STAR Heavy Flavor Tracker
– A new modest upgrade proposed in addition is a Muon
Telescope Detector (MTD) to measure quarkonia and e-μ
correlations
– Benefits of MTD:
• Different signal with different systematics for comparison (no 
conversions; much less Dalitz contribution)
• Improved invariant mass resolution due to no Bremsstrahlung
• New trigger capability unavailable otherwise
• Ability to separate lepton pair production from heavy quark decays
TJH, TOF Workshop Hangzhou April 2009
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The next step for STAR
100M central Au+Au
D0 + D0, RHIC II
Topological PID
pileup included
STAR Heavy Flavor Tracker (HFT)
- 2-layer Active Pixel Sensors: 30 m pitch
thickness x/x0 ~ 0.3% per layer
2.5cm inner radius; 200s integration
- 1-layer* Si strips
- SSD: x/x0 ~ 1%
|| ≤ 1
pT > 0.5 GeV/c: e, D0,±,s,*, c , B…
D-D correlation functions
TJH, TOF Workshop Hangzhou April 2009
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Another new STAR direction: di-muon study of quarkonia
Quarkonium dissociation temperatures – Digal, Karsch, Satz
The
temperature
at which
various
resonances dissociate is a matter of debate,
A large area
of muon
telescope detector
(MTD)
at midBut there
no debate
rapidity, allows
for theisdetection
of: that different binding will lead to different dissociation
+-
patterns which can be used to study color screening in the medium
•
di-muon pairs from QGP thermal radiation,
quarkonia, light vector mesons, possible
correlations of quarks and gluons as resonances
in QGP, and Drell-Yan production
•
single muons from their semi- leptonic decays of
heavy flavor hadrons
•
advantages over electrons: no  conversion,
much less Dalitz decay contribution, less affected
by radiative losses in the detector materials
The , ’, ’’ should behave differently than the J/
• (1S) no melting at RHIC  standard candle
• (2S) likely to melt at RHIC (analog J/)
• (3S) melts at RHIC (analog ’)
Features
• co-mover absorption small
• recombination negligible at RHIC
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The basic idea: an MRPC with long strips
Long MRPC Technology with doubleend readout
256 mm
Time Resolution (ps)
Efficiency (%)
950 mm
25 mm
HV:  6.3 KV
gas mixture: 95% Freon + 5% isobutane
time resolution: ~ 60 ps
spatial resolution: ~ 1cm
efficiency: > 95%
Y. Sun et al., nucl-ex/0805.2459; NIMA 593, 430 (2008)
TJH, TOF Workshop Hangzhou April 2009
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The STAR Detector
MRPC ToF barrel
MTD (BNL LDRD)
EMC barrel
EMC End Cap
75% for run 9
RPSD
FMS
FPD
TPC
PMD
Complete
Ongoing
DAQ1000
Take data
HFT:
R&D
FGT
TJH, TOF Workshop Hangzhou April 2009
R&D
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Concept of Design
Efficiency for detecting muons (top) and
hadrons (bottom) after the STAR return steel
A pseudo 2 detector with scintillator covering the whole iron bars, leaving the gaps in-between
Basic strategy:
detect
charged56.6%
particles
which do not range out in the return
uncovered.
Geometric
Acceptance:
at ||<0.8
steeldetection
of the STAR
magnet,
tracks inefficiency:
the STAR0.5-1%
TPC match
1. muon
efficiency:
~45%,whose
pion detection
at pT>2 within
GeV/c 400 ps
with the hit position in a multi-gap resistive plate chamber having long longitudinal
2. muon-to-pion enhancement factor: 50-100 within MTD geometric acceptance
strips read out on both ends
3. muon-to-hadron enhancement factor: 100-1000 including track matching, TOF and dE/dx
4.This
dimuontogether
trigger enhancement
factor will
fromgreatly
online trigger:
10-50our capability for J/ and
with DAQ1000
enhance
TJH, TOF
April 2009
other dilepton studies at RHIC
II Workshop
and aHangzhou
possible
future electron-ion collider 10
Simulation: J/ efficiency with full MTD
J/ efficiency
J/ efficiency
 acceptance
STAR
A pseudo 2 detector with scintillator covering the whole iron bars and left the gaps in-between
uncovered. Acceptance: 56.6% at || < 0.8
1. J/ efficiency  acceptance: > 1% at low pT, ~ 10% at high pT
TJH, TOF Workshop Hangzhou April 2009
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Novel & Compact Muon Detector
• Novel and compact -------- Concept
timing, position  track segments + fastHits
• Muon is a penetrating probe → affords (complementary) J/
trigger, separates +- 1s, 2s, 3s states
• Useful for RHIC II and possible Electron Ion Collider (EIC))
• Works with accelerator high luminosity upgrades
• R & D needed to address: spatial and time resolution, muon
identification capability, trigger capability and hadron rejection
power
TJH, TOF Workshop Hangzhou April 2009
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Fermi Lab Beam Test Setup (T963 May 2-15 2007)
449”
252”
73”
72”
191”
81
45
C1, C2
70”
164”
33
TOF2
MRPC1&2
MWPC2
MWPC5
MWPC1
MWPC3
TOF1 TOF3
11”
GEMs
MWPC4
Upper
stream
Down
stream
TOF1
AND
Trigger, common start
TOF2
Test the performance of two long MRPC modules under different working conditions. Comprehensive
scans on HV, gas mixture, position, beam energy, etc … (T963 spokesman: Zhangbu Xu)
TJH, TOF Workshop Hangzhou April 2009
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Beam Test Results
100
90
500
Tracking position vs mean time position
Timing Resolution (ps)
USTC
Tsinghua
module as
trigger
80
400
300
Scintillator
as trigger
70
200
60
Single charged particle efficiency (%)
100
50
36
40
44
48
52
40
E (kV/cm)
HV:  6.3 KV
gas mixture: 95% Freon + 5% isobutane
time resolution: ~ 60-70 ps
spatial resolution: ~ 0.6-1cm
efficiency: > 95%
consistent with cosmic test results
45
50
55
E (kV/cm)
Tracking position vs
mean time position
TOF Workshop
Hangzhou
April 2009
Y. Sun et al., nucl-ex/0805.2459;TJH,
NIMA
593, 430
(2008)
σ = 0.6 cm
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STAR-MTD in Year 2007 and 2008
collision system
Interaction rate
trigger rate
Sampled L
events
matched hits
Au+Au
20 k
0.5-2 Hz
270 b-1
0.31 M
7k
d+Au
100 k
0.5-2 Hz
29 nb-1
1.60 M
78 k
p+p
300 k
0.5-2 Hz
404 nb-1
0.56 M
8k
• iron bars as hadron absorber
• 403 cm away from TPC center, || < 0.25
• gas: 95% Freon and 5% iso-butane; HV: 6.3 KV
TJH, TOF Workshop Hangzhou April 2009
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Performance of an MTD prototype at STAR
Comparison of hit position from
tracking vs mean time in MTD
• MTD hits: matched with real high pT
tracks
• z distribution has two components:
narrow (muon) and broad (hadron)
ones
• spatial resolution (narrow Gaussian)
is ~10 cm at pT > 2 GeV
• narrow to broad ratio is ~2; can be
improved with dE/dx and TOF cut
Azimuthal location and transverse momenta for
hits matched between the MTD and TPC tracks
• are the particles in the narrow
Gaussian muons?
Location of prototype
MTD tray in azimuth
TJH, TOF Workshop Hangzhou April 2009
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Compared to Simulation
Expected spatial resolution for matched hits (TPC and MTD) from simulation
muons
pT (GeV/c)
muons
20
pions
10
z (cm)
0
20
40
60
80
Δz (cm)
From data: pT > 2 GeV/c, (z) of muon: ~10 cm
From simulation: pT = 2.5 GeV/c, (z) of muon: ~9 cm
Data and simulation show consistent results
TJH, TOF Workshop Hangzhou April 2009
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100
TPC – TOF position match window
Muon Identification: Cut on TPC dE/dx
STAR Preliminary
STAR Preliminary
The trick:
|z|<20
At pT > 2 GeV/c the dE/dx for a
μ in the TPC is 3-4 % (0.5 σ) higher
than for a  (about 2σ different
Signal
Background
Total
than a Kaon)
Number of σ away from pion dE/dx
in TPC for TPC tracks matched with MTD hits
STAR Preliminary
n<-1
So by cutting on the nσ --the
STAR Preliminary
difference in σ from the dE/dx
expected for a pion track we can
discriminate against , K background
n>0
 and K muon secondaries reduced
by dE/dx cut in TPC
• The narrow Gaussian
distribution: dominated by muons
TJH, TOF Workshop Hangzhou April 2009
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TPC – TOF position match window
Muon Identification: Cut on High Velocity and dE/dx
STAR Preliminary
STAR Preliminary
The trick:
What is measured in the TPC is
momentum ( p = mv )
TPC – TOF position match window
For a given momentum
> vTOF
By requiring velocity comparison in vTPC
consistent with μ hypothesis, i.e.
muonand
pion >IsvKaon
Muon
, K
1/trackhits- 1/rawhits >0
And cutting on TPC
dE/dx
So if a , K momentum is assigned
to a μ candidate,
1/βtrackhits - 1/βTOF< 0
n>0
STAR Preliminary
STAR Preliminary
STAR Preliminary
Number of σ away from pion dE/dx
in TPC for TPC tracks matched with MTD hits
• the narrow Gaussian
distribution: dominated by muons
TJH, TOF Workshop Hangzhou April 2009
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Using EMC Information to check how well
hadrons showers are rejected by MTD hits
The fraction of TPC tracks which match with a non zero EMC energy (> MIP)
pT (GeV/c)
EMC & non-MTD (A) (%)
EMC & MTD (B) (%)
1.5-2
2.21  0.03
0.18  0.02
2-3
3.67  0.07
0.30  0.04
3-4
5.89  0.22
0.34  0.10
4-6
7.92  0.50
0.65  0.24
• B is a factor of 10 smaller than A.
• Composition of hadrons is reduced from ~100% to ~10%;
• Muons (prompt and hadron decays) increase from ~0 to ~90%.
Requiring MTD hit
rejects hadrons showers
by a factor of ~ 10
• The narrow Gaussian is indeed dominated by muons: pion/kaon decay before the EMC
TJH, TOF Workshop Hangzhou April 2009
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Contributions to the inclusive muon yield
K0short with
both ’s in TPC
out of MTD
acceptance
K0short with
one  in TPC in
MTD acceptance
By selecting a pion in the TPC which pairs correctly
with a second pion for the K0short → + - hypothesis
we create a “calibrated” pion beam that can be
used to determine the percentage of muon
candidates with MTD hits that come from secondary
pion decays. The answer is about 30-40%
By comparing the total inclusive muon signal to the
previously measure yield for non-photonic electrons
we can estimate how much of the inclusive muons
signal is due to prompt muons vs secondary decays.
the answer is the primary muons are about 6-10%
of the total inclusive
Pion contribution to muon (background): 30-40%
Others from kaon (background): dominant contributor
Primary muon (signal):6-10%
With dE/dx cut, the S/B ratio is enhanced by a factor of 3.
TJH, TOF Workshop Hangzhou April 2009
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Physics Perspectives with Full Coverage
1. J/: S/B=7 in d+Au and S/B = 2 in central Au+Au
2. e correlation from ccbar: S/B = 2 (Meu> 3 GeV/c2 and pT(e) < 2 GeV/c)
S/B = 8 with electron pairing and TOF association
TJH, TOF Workshop Hangzhou April 2009
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Position expected from MTD vs VPD timing
Trigger Capability with Full Coverage
collision system
L0 rate
reduction
0-80% Au+Au
0.19
0-5% Au+Au
0.53
60-80% Au+Au
0.03
d+Au
0.02
p+p
0.01
L2 reduction
with TOF
RHIC II
luminosity (Hz)
di-muon
L2 rate
~ 0.3
100k
~ 500 (100)
0.003
2M
 10
Position resolution
available at the trigger
level
Estimate from
projection
σ~ 6 cm
With TOF hit association, TJH,
theTOFdi-muon
L2 April
reduction
is 1/8 in central Au+Au
Workshop Hangzhou
2009
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Summary and Future Plan
•
Cosmic and beam tests:
intrinsic timing resolution of long MRPC: ~60-70 ps
spatial resolution: ~1 cm
•
The prototype of MTD works at STAR.
---- clear narrow muon peak
---- Muon purity can be achieved >80%
•
The primary muon over secondary muon ratio is good for quarkonium program
•
The trigger capability with L0 and L2 is promising for dimuon program: Upsion, J/
elliptic flow v2 and RAA at high pT
One Final Comment…
TJH, TOF Workshop Hangzhou April 2009
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Chinese PHD Graduates at STAR
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Shengli Huang, University of Science and Technology of China - USTC
Hard and Soft Interactions in 200 GeV Proton-Proton Collisions
Ph.D. thesis, 2004
R&D Work on MRPC cosmic ray test
Lijuan Ruan, University of Science and Technology of China - USTC
Pion, Kaon, Proton and Antiproton Spectra in d+Au and p+p Collisions at sqrt(sNN) = 200 GeV at the Relativistic Heavy Ion Collider
Ph.D. thesis, 2004
First MRPC TOF results in the world (not just STAR) (Goldhaber Fellow)
Xin Dong, University of Science and Technology of China - USTC
Single Electron Transverse Momentum and Azimuthal Anisotropy Distributions: Charm Hadron Production at RHIC
Ph.D. thesis, 2005
First non-photonic electron from Heavy-flavor using TPC+TOF electron PID (2005年度中国科学院院长特别奖)
Zhixu Liu, Institute of Particle Physics
Proton and Anti-Proton Production at mid-Rapidity from Au+Au Collisions at sqrt(sNN) = 200 GeV
Ph.D. thesis, 2005
Work on Time-of-Flight Patch at STAR
Guoliang Ma, Shanghai Institute of Applied Physics – SINAP
f production
Ph.D. thesis, 2006 (2006年度中国科学院院长奖)
Yifei Zhang, University of Science and Technology of China - USTC
Measurement of charm production cross-section and leptons from its semileptonic decay at RHIC
Ph.D. thesis, 2007
TOF data in Au+Au collisions
Haidong Liu, University of Science and Technology of China - USTC
Production of meson, baryon and light nuclei (A=2,3): investigating freeze-out dynamics and roles of energetic quarks and gluons in Au+Au collisions at
RHIC
Ph.D. thesis, 2007
TOF data in Au+Au collisions
Xiaoyan Lin, Institute of Particle Physics
Non-Photonic Electron Angular Correlations with Charged Hadrons from the STAR Experiment: First Measurement of Bottom Contribution to Non-Photonic
Electrons at RHIC
Ph.D. thesis, 2007
Yan Lu, Institute of Particle Physics
Centrality dependence of K_S and Lambda elliptic flow in Au+Au collisions at sqrt(s_NN)=200 GeV
Ph.D. thesis, 2007
Aoqi Feng, Institute of Particle Physics
Jinghua
Di-hadron Azimuthal Correlations Relative
to ReactionFu
Plane in Au + Au Collisions at sNN = 200 GeV
Ph.D. thesis, 2008
(IOPP/Tsinghua U.):
Xiangming Sun, Lawrence Berkeley National Laboratory
TopElectronics
100 for Heavy Flavor Tracker
Statistical Model in Heavy Ion Collisions2005
and Readout
Ph.D. thesis, 2008
Thesis in China Award
Jinhui Chen, Shanghai Institute of Applied Physics – SINAP
f production and v2
Ph.D. thesis, 2007
Jinghua Fu, IOPP, Wuhan, Ph.D. Thesis 2005
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In conjunction with the STAR TOF project, 13 outstanding
students have already received PhD’s on STAR research and
have produced world class scientific results in the process
Let’s continue this marvelous success story with further fruitful
US-China collaboration on the next generation of detector
instrumentation and scientific analyses on STAR
Xin Dong (USTC):
CAS Early Career
Scientist Award
Proposal for a Novel and Compact Muon Telescope Detector
•
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Submit it to Nucl. Phys. A for publication in two weeks.
Expand it into a MTD proposal:
Brookhaven National Laboratory
Ken Asselta, Bill Christie, Lijuan Ruan, John Scheblein, Robert Soja, Zhangbu Xu
University of California, Berkeley
Hank Crawford, Jack Engelage
Rice University
Geary Eppley, Bill Llope, Ted Nussbaum
University of Science and Technology of China
Hongfang Chen, Cheng Li, Yongjie Sun, Zebo Tang
Shanghai Institute of Applied Physics
Xiang-Zhou Cai, Fu Jin, Yu-Gang Ma, Chen Zhong
Texas A&M University
Saskia Mioduszewski
University of Texas -- Austin
Jerry Hoffmann, Jo Schambach
Tsinghua University
Yi Wang, Xiaobin Wang
Yale University
TJH,Guoji
TOF Workshop
Hangzhou
April 2009
Lin, Richard
Majka
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Towards the Future at STAR
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To install another tray with TOF electronics in run9
Collaborators for a proposal of full scale detector: 56.6% in azimuth, |eta|<0.8; current
module design: 360 modules, 1440 read-out strips, 2880 readout channels; electronics
expense: 400 k + 300 k $.
•
Based on Au+Au run7, L0 trigger for single hit: 0.19 per vpd-mb events in Au+Au
collisions with full coverage. Online trigger enhancement for dimuon: 28.
1 billion MB Au+Au events : 60 M MTD triggered dimuon events: J/+-:
43.8*10-9/0.040*109*292*0.07*0.32*1.6*0.5=5600
+-: 91*1012/0.040*109*292*0.5*0.32*1.6*0.5=85
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RHICII Lumonisinty: 20 nb-1 Au+Au and 360 pb-1 p+p run:
p+p: J/+-: 43.8*10-9 *360*1012 *0.07*0.32*1.6*0.3=169 K
+-: 91*10-12*360*1012 *0.5*0.32*1.6*0.3=2500
Au+Au: J/+- (630 K) +- (9300)
TJH, TOF Workshop Hangzhou April 2009
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Novel & Compact Muon Detector for QCDLab
• Novel and compact -------Convention
timing, position  track
segments + fastHits
• QCDLab (RHIC II, eRHIC)
• Works with accelerator high
luminosity upgrades
• Muon is penetrating probe
J/ trigger, separate
+- states;
vector meson;
thermal dileptons …
TJH, TOF Workshop Hangzhou April 2009
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