E.C. Aschenauer EIC INT Program, Seattle 2010 - Week 1 The Physics we want to study What is the role of.
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Transcript E.C. Aschenauer EIC INT Program, Seattle 2010 - Week 1 The Physics we want to study What is the role of.
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
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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
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EIC INT Program, Seattle 2010 - Week 1
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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
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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
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EIC INT Program, Seattle 2010 - Week 1
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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
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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
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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
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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
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EIC INT Program, Seattle 2010 - Week 1
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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
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EIC INT Program, Seattle 2010 - Week 1
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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
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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
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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
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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
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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
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BACKUP
E.C. Aschenauer
EIC INT Program, Seattle 2010 - Week 1
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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
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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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