Transcript PHENIX, STAR AND AN EIC E.C. Aschenauer EIC INT Program, Seattle 2010, Week 10

PHENIX, STAR AND AN EIC
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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The Physics we want to study
 What is the role of gluons and gluon self-interactions in nucleons and
nuclei?
 Observables in eA / ep:
 diffractive events: rapidity gap events, elastic VM production, DVCS
 structure functions F2A, FLA, F2cA, FLcA, F2p, FLp,………

What is the internal landscape of the nucleons?
 What is the nature of the spin of the proton?
 Observables
in ep
 inclusive, semi-inclusive Asymmetries
 electroweak Asymmetries (g-Z interference, W+/-)
 What is the three-dimensional spatial landscape of nucleons?
Observables in ep/eA
 semi-inclusive single spin asymmetries (TMDs)
 cross sections, SSA of exclusive VM, PS and DVCS (GPDs)

What governs the transition of quarks and gluons into pions and
nucleons?
 Observables in ep / eA
 semi-inclusive c.s., ReA, azimuthal distributions, jets
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Kinematic Plane
Need to study hadronic method
to increase y acceptance
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Lepton Kinematics
Follow Hera Convention:
Hadron beam positive z (=> q = 0o)  Lepton beam negative z => q = 180o)
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Hadron Kinematics
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Kinematics of elastic diffraction
no cuts:
4x100
4x50
4x250
cuts: Q2 > 0.1 GeV && y < 0.9 GeV
decay products of r & J/ψ
go more and more
forward with
increasing
asymmetry in
beam energies
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Diffractive Physics: p’ kinematics
t=(p4-p2)2 = 2[(mpin.mpout)-(EinEout - pzinpzout)]
4 x 50
Diffraction:
?
4 x 50
4 x 250
4 x 100
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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IP configuration for eRHIC
Nice design for protons from exclusive reactions and nuclear breakup particles
pt > 1.5GeV  main detector
0.1 MeV < pt < 1GeV after dipole
pc/2.5
4.5 cm
neutrons
11.2 cm
q=10 mrad
IP
2
4
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8
10
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Dipole:
2.5 m, 6Tm
q=18 mrad
E.C. Aschenauer
Estimated b*≈ 8 cm
EIC INT Program, Seattle 2010, Week 10
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IR Design
eRHIC - Geometry high-lumi IR with β*= 8cm, l*=4.5 m
and 10 mrad crossing angle
Dipole to separate p/A beam
from “recoil”/breakup particles
D5
5.75 cm
10
17.65 m
20
0.44843 m
0.333 m
0.39065 m
325 GeV p
Or 125 GeV/u ions
30 GeV e-
30
60.0559 m
90.08703 m
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
© D.Trbojevic
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Current PHENIX Detector at RHIC
MPC
Muon Arms
South:
North:
Central Arms
3.1 < | h | < 3.9
2.5o < Q < 5.2o
1.2 < | h | < 2.4
12o < Q < 37o
10o < Q < 37o
| h | < 0.35
60o < Q < 110o
electrons will not make it
to the south muon arm
 to much material
p/A
E.C. Aschenauer
eEIC INT Program, Seattle 2010, Week 10
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What will the current PheniX see
pe: 0-1 GeV
pe: 2-3 GeV
pe: 3-4 GeV
4x100
pe: 1-2 GeV
Current PheniX detector
not really useable for
DIS
acceptance not matched to DIS kinematics
4x100
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
4x100
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The New PheniX Spectrometer
Design completely driven by AA, dA and pp physics program
ep/A
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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What can we detect
pe: 0-1 GeV
pe: 1-2 GeV
pe: 2-3 GeV
pe: 3-4 GeV
4x50
No dependence on hadron beam energy
Q2>0.1GeV2
4GeV  >5o
10GeV  >2o
20GeV  >1o
New PheniX has close to full coverage for scattered lepton
Forward upgrade
identified hadrons
4x100
5 GeVx50GeV
20 GeV x 250 GeV
central arm
unidentified
North m arm
only muons
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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The STAR Detector
Tracking: TPC
Particle ID: TOF
Electromagnetic
Calorimetry:
BEMC+EEMC+FMS
(-1 ≤ h ≤ 4)
Upgrades:
Muon Telescope
Detector
Roman Pots Phase 2
Forward Upgrade
Heavy Flavor
Tracker (2013)
Full azimuthal particle identification
E.C. Aschenauer
over a broad range in pseudorapidity
EIC INT Program, Seattle 2010, Week 10
Forward Gem
Tracker
(2011)
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STAR Experiment as of 2014
MRPC ToF Barrel
MTD
EMC Barrel
EMC End Cap
FMS
BBC
FPD
Roman Pots
Phase 2
TPC
computing
DAQ1000
COMPLETE
Trigger and DAQ
Upgrades
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HFT
FGT
EIC INT Program, Seattle 2010, Week 10
Ongoing
R&D
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STAR Forward Upgrade
proton
nucleus
 Positive η: Drell Yan
 High precision tracking and
background rejection using
calorimetry
 Optimized for p+A and p+p
 High momentum scale
 Negative η: eRHIC
 Optimized for low energy
electrons (~1 GeV)
 Triggering, tracking,
identification
 R&D necessary for optimal
technology choice
nucleus
electron
To fully investigate cold QCD matter, STAR will move forw
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Energy loss in cold QCD matter
Hermes, Nucl. Phys.B 780, 1 (2007)
RA π
Lc ∝ ν: Lc up to few 100 fm
 Complementary probe of mechanism of energy loss
 HERMES: mixture of hadronic absorption and partonic loss
 Hadrons can form partially inside the medium
 eRHIC: light quarks form far outside medium
 Heavy quarks: unexplored to date. Low β: short formation time
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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STAR and eRHIC Phase I
 Current detector matches quite well to kinematics of eRHIC
 Particle ID, sufficent pT resolution, etc. at mid-rapidity
 Upgrades in forward direction: increase capability at lower momentum
 Developing plan for effective and compelling use of e+A
E.C. Aschenauer
EIC INT Program, Seattle 2010, Week 10
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Longer term: STAR and eRHIC
 Forward region critical for higher energy options
 Major upgrades in forward direction would be needed
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EIC INT Program, Seattle 2010, Week 10
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Summary
 Both, the new PheniX and STAR have reasonable capabilities for
ep/eA collisions
 inclusive measurements
 some initial semi-inclusive measurements as well as for heavy quarks
 BUT no replacement for a dedicated detector
 using STAR and/or PHENIX might help to release some of the
requirements on the dedicated detector
 need still to resolve all the details how to bring the lepton beam
with 10mrad in the detectors for collisions and the non-colliding
beams around.
 STAR seems easier
E.C. Aschenauer
than PHENIX
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