E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
1
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 1
2
Processes used to study the Physics
exclusive
/diffractive
reactions
semi-inclusive
reactions
ep/A e’pX
ep/A  e’p’/A’VM
Close to 4p
acceptance
Excellent
electron
identification
good jet
identification
Detect
outgoing
scattered
proton
very precise
polarization
measurement
E.C. Aschenauer
inclusive
reactions
ep/A  e’X
excellent
absolute
and/or
relative
luminosity
electro-weak
reactions
Background
suppression
PID:
to identify
Hadrons
Detect
very low Q2
electron
high demands on
momentum and/or
good vertex energy resolution
EIC INT Program, Seattle 2010 - Week 1
resolution
3
Kinematics of scat. electron
4 GeV
Electron Energy
20 GeV
10 GeV
50 GeV
Proton Energy
100 GeV
250 GeV
scattered lepton
goes to smaller
angles as
√s increases
For any hadron beam energy
Q2>0.1GeV2
4GeV  >5o
10GeV  >2o
20GeV  >1o
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
4
Kinematics of semi-inclusive hadrons
no cuts:
4x50
4x100
4x250
cuts: Q2 > 0.1 GeV && y < 0.9 GeV
momentum (GeV)
hadrons go
more and more
forward with
increasing
asymmetry in
beam energies
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
5
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 1
6
Diffractive Physics: p’ kinematics
t=(p4-p2)2 = 2[(mpin.mpout)-(EinEout - pzinpzout)]
Diffraction:
4 x 50
?
p’
4 x 250
need “roman pots”
to detect the protons
and a ZDC for
neutrons
4 x 100
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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Additional Remarks
 General Remarks
 detector should have stable acceptance to enable efficient running at
different energies (5 GeV x 50 GeV to 30 GeVx325 GeV)
 Charm detection
 structure functions
detecting lepton form decay in addition to scattered via displaced
vertex should be enough
 charm in fragmentation
need to reconstruct D0 meson completely to measure its z
 good PID
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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Measure gA(x) impact parameter dependent
Basic Idea:
Studying diffractive exclusive J/y production
at Q2~0
Ideal Probe:
large photo-production cross section
t can be derived from e,e’ and J/y 4-momentum
pt2 = t for elastic J/y
What are the requirement:
 Momentum resolution
 t resolution and range
 what breakup particles need to
be detected?
 n enough or p also needed?
E.C. Aschenauer
A. Caldwell, H. Kowalski Phys.Rev.C81:025203,2010
EIC INT Program, Seattle 2010 - Week 1
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How to measure coherent diffraction in e+A ?
 Beam angular divergence limits smallest
outgoing Qmin for p/A that can be
measured
 Can measure the nucleus if it is separated
from the beam in Si (Roman Pot)
“beamline” detectors
 pTmin ~ pzAθmin
For beam energies = 100 GeV/n and
θmin = 0.1 mrad:
 Large momentum kicks, much larger
than binding energy (~8 MeV)
 Therefore, for large A, coherently
diffractive nucleus cannot be separated
from beamline without breaking up
E.C. Aschenauer
species
(A)
d (2)
Si (28)
Cu (64)
In (115)
Au (197)
U (238)
EIC INT Program, Seattle 2010 - Week 1
pTmin
(GeV/c)
0.02
0.22
0.51
0.92
1.58
1.90
10
How to measure coherent diffraction in e+A ?
Purity Efficiency
 Rely on rapidity gap method
 simulations look good
 high eff. high purity
possible with gap alone
~1% contamination
~80% efficiency
 depends critical on detector
hermeticity
 improve further by veto on
breakup of nuclei (DIS)
 Very critical
 mandatory to detect nuclear
fragments from breakup
 n: Zero-Degree calorimeter
 p, A frag: Forward Spectrometer
E.C. Aschenauer
rapidity
EIC INT Program, Seattle 2010 - Week 1
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Emerging Detector Concept
Forward / Backward
Spectrometers:
high acceptance -5 < h < 5 central detector
good PID and vertex resolution
tracking and calorimeter coverage the same  good momentum resolution
low material density  minimal multiple scattering and bremsstrahlung
forward electron and proton dipole spectrometers
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
12
First Model of eRHIC Detector
Traditional
Drift-Chambers
better GEM-Tracker
Si-Vertex
as Zeus
Central Tracker
as BaBar
Hadronic
Calorimeter
Dual-Radiator
RICH
as LHCb /
HERMES
EM-Calorimeter
PbGl
High Threshold
Cerenkov
fast trigger on e’
e/h separation
 DIRC: not shown because of cut;
modeled following Babar
 no hadronic calorimeter and m-ID jet
 CALIC technology combines mID with HCAL
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
13
Technology choices and needed R&D
 Some thoughts about technologies
 LHC trackers have all to much radiation length
GEM trackers and ILC Si detectors would be much better
 Forward calorimeters small moliere radius  PbWO4
especially important for hadron direction  DVCS
Preshower: g -p0 separation  Si-WO
 Central calorimeter
needs to be compact with a pointing geometry
sampling calorimeter with accordion structure
 Needed R&D
 low mass trackers
 compact calorimetry for inside solenoid
 ion polarimetry  currently at best 5% systematic uncertainty
at RHIC
Bjoerken sum rule measurement requires ~2%
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
14
IR-Design
10
20
0.329 m
0.188036 m
0.44 m
eRHIC - Geometry high-lumi IR with β*=5 cm, l*=4.5 m
and 10 mrad crossing angle
30 GeV e-
30
60 m
m
90 m
© D.Trbojevic
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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A detector integrated into IR
space for
e-polarimetry
and luminosity
measurements
ZDC
FPD
FED
 for ERL solution need not to measure electron polarization bunch by bunch
 need still to integrate luminosity monitor
 need still to integrate hadronic polarimeters, maybe at different IP
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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Can we detect DVCS-protons and Au break up p
 track the protons through solenoid, quads and dipole with hector
 beam angular spread 0.1mrad at IR
 Quads +/- 5mrad acceptance
 Proton-beam: p’z> 0.9pz
 100 GeV: ptmax < 0.45 GeV  tmax < 0.2 GeV2
 Detector: acceptance starts Θ > 50mrad
 need more work to find a way to cover intermediate range
 solution could be to do the same as for the electrons swap the
dipole and quads
proton track Dp=10%
E.C. Aschenauer
proton track Dp=20%
proton track Dp=40%
Equivalent to fragmenting
protons from Au in Au optics
(197/79:1 ~2.5:1)
EIC INT Program, Seattle 2010 - Week 1
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Jlab: Detector/IR cartoon
Slides Rolf Ent
Make use of a 100 mr crossing angle for ions!
solenoid
0 mrad
(approximately to scale)
detectors
ion dipole w/ detectors
IP
electron FFQs
100 mrad
2+3 m
2 m
Central detector,
more detection space
in ion direction as
particles have higher
momenta
electrons
2 m
100 mr crossing angle
3.5 m distance IP – electron
FFQs
 Easy to squeeze baby-size
electron FFQs in here
Distance IP – electron FFQs = 3.5 m
Distance IP –
ion FFQs = 7.0 m
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
18
Jlab: Where do particles go - mesons
{
SIDIS p
Need Particle ID

Need Particle ID

Slides Rolf Ent
1H(e,e’π+)n
4 on 60
{
11 on 60
for p > 4 GeV in central region
DIRC won’t work, add threshold Cherenkov or RICH
for well above 4 GeV in forward region (< 30o?)
determines bore of solenoid
In general: Region of interest up to ~10 GeV/c mesons
Momentum ~ space needed for detection
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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Jlab: Overview of Central Detector Layout
Slides Rolf Ent
Solenoid yoke + Muon Detector
TOF
•
2m
3m
Muon Detector
Hadron Calorimeter
EM Calorimeter
RICH
Tracking
•
TOF (5-10 cm)
•
RICH (60-100 cm)
–
•
2m
•
IP is shown shifted left by 0.5 meter here, can be shifted
–
Determined by desired bore angle and forward tracking resolution
–
Flexibility of shifting IP also helps accelerator design at lower
energies (gap/path length difference induced by change in crossing
angle)
E.C. Aschenauer
Crystals, small area
–
RICH
HTCC
EM Calorimeter
Solenoid yoke + Hadronic Calorimeter
EM Calorimeter (30-50 cm)
C4F8O + Aerogel
Or DIRC (10 cm) + LTCC (60-80 cm)
–
C4F8O gas
–
π/K: 4 - 9 GeV/c (threshold)
–
e/π: up to 2.7 GeV/c (LTCC)
–
K/p: up to 4 GeV/c (DIRC)
EIC INT Program, Seattle 2010 - Week 1
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Jlab: Detector/IR cartoon
Slides Rolf Ent
Make use of a 100 mr crossing angle for ions!
solenoid
(approximately to scale)
detectors
ion dipole w/ detectors
0 mrad
IP
electron FFQs
100 mrad
2+3 m
2 m
electrons
2 m
Detect particles with
angles down to 0.5o
Need up to 2 Tm
dipole bend, but not
too much!
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
21
Jlab: Detector/IR cartoon
Slides Rolf Ent
Make use of a 100 mr crossing angle for ions!
solenoid
ion dipole w/ detectors
IP
electrons
electron FFQs
100 mrad
2+3 m
2 m
2 m
Downstream dipole on ion beam line ONLY has
several advantages
–
No synchrotron radiation
–
Electron quads can be placed close to IP
–
Dipole field not determined by electron energy
–
Positive particles are bent away from the electron
beam
–
Long recoil baryon flight path gives access to low -t
–
Dipole does not interfere with RICH and forward
calorimeters
• Excellent acceptance (hermeticity)
E.C. Aschenauer
4 on 30 GeV
Q2 > 10 GeV2
0 mrad
•
(approximately to scale)
detectors
0.2 2.5°
recoil baryons
exclusive mesons
EIC INT Program, Seattle 2010 - Week 1
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and Summary
 Quite some progress on integrating detector in machine
design
 Main features of detector design identified and implemented
in design
BUT
 need more feedback on requirements from physics groups
 which hopefully comes with defining the physics program for an
EIC @ the INT
 BNL: look into the possibilities to use existing detectors
eSTAR, ePHENIX
 eSTAR & ePHENIX look promising, but have some restrictions
compared to a dedicated detector
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
23
BACKUP
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
24
Detector Requirements from Physics
 Detector must be multi-purpose
 Need the same detector for inclusive (ep -> e’X), semi-inclusive (ep ->
e’hadron(s)X), exclusive (ep -> e’pp) reactions and eA interactions
 Able to run for different energies (and ep/A kinematics) to
reduce systematic errors
 Ability to tag the struck nucleus in exclusive and diffractive eA
reactions
 Needs to have large acceptance
 Cover both mid- and forward-rapidity
 particle detection to very low scattering angle; around 1o in e and p/A
direction
 particle identification is crucial
 e, p, K, p, n over wide momentum range and scattering angle
 excellent secondary vertex resolution (charm)
 small systematic uncertainty for e,p-beam polarization and
luminosity measurement
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
25
eRHIC – Geometry high-lumi IR
eRHIC IR1
p /A
e
Energy (max), GeV
325/130
20
Number of bunches
166
74 nsec
Bunch intensity (u) , 1011
2.0
0.24
Bunch charge, nC
32
4
m
1
2
Beam current, mA
3
4
5
Normalized emittance, 1e-6 m, 95% for p / rms
for e
6
420
1.2
10 mrad
7
© 50
D.Trbojevic
25
 Two designs of the IR exist for both low luminosity (~
and high
Polarization,
80
luminosity% (~ 2x1034) depends on distance IR to70focusing quads
length,
cm
4.9 can have energy0.2
rms
Bybunch
using
a crossing
angle (and crab cavities), one
independent geometries for the IRs and no synchrotron radiation in the
β*, cm
5
5
detectors
1.46 x 1034
Luminosity,
Big advantage
in
detecting
particles
at
low
angle
-2
-1
cm s
(including hour-glass effect
 can
as e-beam
low asoperation
0.75owillatbehadron
side  |h|
< h=0.851)
5.5 Beam-p: y ~ 6.2
Luminosity
for go
30 GeV
at 20% level
E.C. Aschenauer
3x1033)
EIC INT Program, Seattle 2010 - Week 1
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STAR @ RHIC
Tracking: TPC
Particle ID: TOF
Electromagnetic
Calorimetry:
BEMC+EEMC+FMS
(-1 ≤  ≤ 4)
Upgrades:
Muon Tracking
Detector
HLT
Heavy Flavor Tracker
(2013)
E.C. Aschenauer
Full azimuthal particle identification
INT Program,
2010 - Week 1
over EIC
a broad
range Seattle
in pseudorapidity
Forward Gem
Tracker
(2011)
27
Kinematics at 4+100
Scattered electron
Scattered jet
4x100 open kinematics: scatters the electron and jet to mid-rapidity
Forward region (FMS): Electron either Q2 < 1 GeV, or very high x and Q2
Jet either very soft or very hard
Note: current thinking has hadron in the blue beam: optimized for high x and Q2
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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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
 would like to have hadrons in
blue beam and leptons in yellow
beam direction
E.C. Aschenauer
29
e-
EIC INT Program, Seattle 2010 - Week 1
What will the current PheniX see
pe: 1-2 GeV
pe: 2-3 GeV
pe: 3-4 GeV
4x100
pe: 0-1 GeV
Current PheniX detector
not really useable for
DIS
acceptance not matched to DIS kinematics
BUT ….
4x100
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
4x100
30
The new PheniX Spectrometer
 Coverage in |h| =< 4 (2o < q < 30o) 0.1 < Q2 < 100 (5o –
175o)
 need an open geometry detector
 planes for next decadal plan
replace current central detector with a new one
covering
=< 1
North
Muon|h|
Arm
145cm
replace South muon arm by a endcap spectrometer
HCAL
80cm
HCAL
EM
CAL
EMCAL
Preshower
R
I
C
H
IP
68cm
60cm
2T Solenoid
Silicon Tracker
VTX + 1 layer
Silicon Tracker
FVTX
1.2 < h < 2.7
8o < q < 37o
5o @ 2m
17.4 cm dy
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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