Tagging the EMC e ect in N using the BAND and LAD ...crex.fmf.uni-lj.si/eep17/schmidt_bled.pdf ·...
Transcript of Tagging the EMC e ect in N using the BAND and LAD ...crex.fmf.uni-lj.si/eep17/schmidt_bled.pdf ·...
Tagging the EMC effect in d(e, e ′N) reactions
using the BAND and LAD detectors at JLab12
Axel Schmidt
MIT
July 5, 2017
LNSLaboratory for Nuclear Science
1
The EMC effect still puzzles.
0.8
1
1.2
0.25 0.5 0.75
SLAC data (1994)
2σC12σd
x
J. Gomez et al., PRD 49 4348 (1994)
Miller + Smith, PRC 65 015211 (2001)
2
The EMC effect still puzzles.
0.8
1
1.2
0.25 0.5 0.75
SLAC data (1994)EMC slope: 0.32
2σC12σd
x
J. Gomez et al., PRD 49 4348 (1994)
Miller + Smith, PRC 65 015211 (2001)
3
The EMC effect still puzzles.
0.8
1
1.2
0.25 0.5 0.75
SLAC data (1994)EMC slope: 0.32
Fermi-motion
2σC12σd
x
J. Gomez et al., PRD 49 4348 (1994)
Miller + Smith, PRC 65 015211 (2001)
4
Classifying EMC Models
NucleonMotion
MediumModification
All nucleonsmodified slightly
A few nucleonsmodified a lot
EMC Models
Insufficient
5
Theories identify virtuality as the key
to producing EMC-like modification.
Binding RescalingPoint-like Configuration
Suppression
Bound
Free
Bound
Free
Bound
Free + ε
+ ε
A - 1
6
Theories identify virtuality as the key
to producing EMC-like modification.
Binding RescalingPoint-like Configuration
Suppression
Bound
Free
Bound
Free
Bound
Free + ε
+ ε
A - 1
7
Theories identify virtuality as the key
to producing EMC-like modification.
Binding RescalingPoint-like Configuration
Suppression
Bound
Free
Bound
Free
Bound
Free + ε
+ ε
A - 1
8
The EMC effect correlates with
the density SRC pairs.
−0.1
0
0.1
0.2
0.3
0.4
0.5
0 1 2 3 4 5 6
2H
3He
4He
9Be
12C
56Fe
197Au
EM
CSl
ope
(−dR/dx B
)
SRC-pair density (a2)
9
Two upcoming experiments will test
the EMC-SRC connection.
Deep inelastic scattering with a recoiling nucleon:
scatteredelectron
jet from struck quark
Deuterium
LAD
11 GeV e–
SHMS
HMS
GEMsspectatorproton
JLab Hall C
scatteredelectron
jet from struck quark
Deuterium
Spectatorneutron
BAND
11 GeV e–
CLAS12
JLab Hall B
10
The Correlations group • MIT (Or Hen): – Barak Schmookler
– Reynier Torres
– Efrain Segarra
– Afro Papadopoulou
– Axel Schmidt
– George Laskaris
– Maria Patsyuk
– Adi Ashkenazy
TAU (Eli Piasetzky): – Erez Cohen
– Meytal Duer
– Igor Korover
• ODU (Larry Weinstein): – Mariana Khachatryan
– Florian Hauenstein • UT Santa Maria (Chile)
IñakiVega
I will cover:
1 Recoil-Tagged DIS
Testing the SRC-EMC connection
2 The ‘LAD’ Experiment
Large Acceptance Detector
3 The ‘BAND’ Experiment
Backward Angle Neutron Detector
12
I will cover:
1 Recoil-Tagged DIS
Testing the SRC-EMC connection
2 The ‘LAD’ Experiment
Large Acceptance Detector
3 The ‘BAND’ Experiment
Backward Angle Neutron Detector
13
Recoil-Tagging: using a high-momentum recoil to
determine the virtuality of the struck nucleon.
ee'
14
Recoil-Tagging: using a high-momentum recoil to
determine the virtuality of the struck nucleon.
ee'
recoilingspectator
15
Short-range correlations are universal.
-1
-0 .8
-0 .6
-0 .4
-0 .2
0
0 .2
0 .4
0 .6
0 .8
1
0.05 0.1 0 .15 0.2 0 .25 0.3 0 .35 0.4 0 .45 0.5 0 .55-1
-0 .8
-0 .6
-0 .4
-0 .2
0
0 .2
0 .4
0 .6
0 .8
1
0.05 0.1 0 .15 0.2 0 .25 0.3 0 .35 0.4 0 .45 0.5 0 .55-1
-0 .8
-0 .6
-0 .4
-0 .2
0
0 .2
0 .4
0 .6
0 .8
1
0.05 0.1 0 .15 0.2 0 .25 0.3 0 .35 0.4 0 .45 0.5 0 .55-1
-0 .8
-0 .6
-0 .4
-0 .2
0
0 .2
0 .4
0 .6
0 .8
1
0.05 0.1 0 .15 0.2 0 .25 0.3 0 .35 0.4 0 .45 0.5 0 .55
pn(GeV /c)
cos�
5.9 GeV/c, 988.0 GeV/c, 989.0 GeV/c, 985.9 GeV/c, 947.5 GeV/c, 94
Recoil neutron momentum [GeV]
Leading
Recoil
�
Parallel
Anti-parallel
High-momentum tail
20% of nucleons
correlated pairs
high-relative momentum
low CoM momentum
J.L.S. Aclander et al., Phys. Lett. B 453, 211 (1999)
A. Tang et al., Phys. Rev. Lett. 90, 042301 (2003)
E. Piasetzky et al., PRL 97 162504 (2006)16
There are some interpretation challenges.
ee'
recoilingspectator
1 relating the recoil momentum to the stuck nucleon momentum
2 rescattering in the nuclear medium
3 accounting for the nuclear remnant
17
There are some interpretation challenges.
ee'
recoilingspectator
1 relating the recoil momentum to the stuck nucleon momentum
2 rescattering in the nuclear medium
3 accounting for the nuclear remnant
−→ Use a deuterium target.
−→ Look at backward recoils.
18
Advantages of deuterium
Struck nucleon had EXACTLY opposite momentum to recoil.
No residual system
Minimal final state interactions.
ee'
recoilingspectator
19
DEEPS showed little FSI at back angles.
(G eV /c)sP
0.3 0 .4 0 .5 0 .6 0 .7
0
1
2
3
(GeV /c)sP
0 .3 0 .4 0 .5 0 .6 0 .7
0
2
4
6
PWIAdata
θqs > 107˚ 73˚ < θqs < 107˚TransverseAnti-Parallel
103 counts
Klimenko et al., PRC 73 035212 (2006)
20
What we want to measure:
F2(x′,Q2, αs)boundF2(x ,Q2)free
≈ σDIS(x′,Q2, αs)bound
σDIS(low x ′,Q20 , αs)bound×σDIS(low x ,Q20 )free
σDIS(x ,Q2)free×RFSI
. Tagged DIS measurement Input ≈ 1
At low x, the EMC effect should be small:
σDIS(low x ′,Q20 , αs)bound ≈ σDIS(low x ,Q20 )free
21
What we want to measure:
F2(x′,Q2, αs)boundF2(x ,Q2)free
≈ σDIS(x′,Q2, αs)bound
σDIS(low x ′,Q20 , αs)bound×σDIS(low x ,Q20 )free
σDIS(x ,Q2)free×RFSI
. Tagged DIS measurement Input ≈ 1
At low x, the EMC effect should be small:
σDIS(low x ′,Q20 , αs)bound ≈ σDIS(low x ,Q20 )free
22
What we want to measure:
F2(x′,Q2, αs)boundF2(x ,Q2)free
≈ σDIS(x′,Q2, αs)bound
σDIS(low x ′,Q20 , αs)bound×σDIS(low x ,Q20 )free
σDIS(x ,Q2)free×RFSI
. Tagged DIS measurement Input ≈ 1
At low x, the EMC effect should be small:
σDIS(low x ′,Q20 , αs)bound ≈ σDIS(low x ,Q20 )free
23
Different models predict different F2 ratios.
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
PLC suppression
Rescaling
Binding
Bou
ndF2
/Fr
eeF2
αs
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
Melnitchouk, Sargsian, Strikman, Z. Phys A 359 p.99 (1997)
24
Experimental Requirements
1 DIS kinematics
W > 2 GeV
Q2 > 2 GeV2
−→ 10 GeV beam energy
2 Backward recoil detector
Large acceptance for θqs > 110◦
0.25 < pr < 0.7 GeV
Low x ′ and High x ′ coverage
25
I will cover:
1 Recoil-Tagged DIS
Testing the SRC-EMC connection
2 The ‘LAD’ Experiment
Large Acceptance Detector
3 The ‘BAND’ Experiment
Backward Angle Neutron Detector
26
LAD will detect recoiling spectator protons.
scatteredelectron
jet from struck quark
Deuterium
LAD
11 GeV e–
SHMS
HMS
spectatorproton
JLab Hall C28
LAD is three panels of scintillator bars,
originally from the CLAS-6 ToFs.
4/18/17 6
LargeDoublePanels#2
LargeDoublePanels#1
LargeSinglePanel#3
EMC-SRCDetectorsDetectorsatthedifferentplanesfromTargetPanelsoverlapreducingoreliminaInggap
DetectorSupportstobedesignedtoclearFlexLine
29
LAD Experiment Details
Experiment Large Acceptance Detector
Experiment E12-11-107
Approved for 820 hours
Extended LD2 target
11 GeV e− beam
1036 cm−2s−1
Low x and high x settings
5 panels of 11 bars
1.5 sr at back angles
80◦–170◦
±20◦ out-of-plane
31
The limit will be random coincidence background.
Can be subracted using
“off-time” events
Statistical variation can
drown signal
δN
N=
√S + B
S
0 20 40 60 80 100
Signal
Reconstructued ToF0 20 40 60 80 100
Any reduction in background buys us statistics!
32
Energy deposition in LAD must match velocity.
44
Figure 25: Energy loss versus TOF.
To reduce the large singles rates we will set the detector threshold in the first layer of scintillators for protons at 20 MeVee (twice the minimum ionizing energy deposit). We will set the detector threshold in the subsequent layers of scintillators for neutrons at 5 MeVee. I.4 Nucleon momentum resolution The best momentum resolution is obtained by calculating the TOF per meter. From the CLAS operational experience, we know that the time resolution for the large angle counters is 200-250 ps. For detectors at about 5 meter from the target and 300-500 MeV/c nucleon
!pp
= !TOFTOF
= 0.250ns(50 " 33)ns
= 0.5 " 0.8%
For recoil protons we can also determine their momentum using the energy loss. Based on experience with BigBite we expect a resolution of about 20 MeV/c.
!pp
= 20MeV/c(500 " 300)MeV/c
= 4 " 7%
33
Energy deposition in LAD must match velocity.
−80 −60 −40 −20 0 20 40 60 80
Signal
Randoms
Rat
e[a
rb.
units]
Momentum (Edep) - Momentum (ToF) [MeV]
34
We plan to add GEMs to assist in vertexing.
scatteredelectron
jet from struck quark
Deuterium
LAD
11 GeV e–
SHMS
HMS
spectatorproton
JLab Hall C35
We plan to add GEMs to assist in vertexing.
scatteredelectron
jet from struck quark
Deuterium
LAD
11 GeV e–
SHMS
HMS
GEMsspectatorproton
JLab Hall C36
Multiple scattering in GEM material
can reduce effectiveness.
0
200
400
600
800
1000
1200
1400
−15 −10 −5 0 5 10 15
σ = 1.3 cm
σ = 1.7 cm
σ = 2.5 cm
Cou
nts
zrec. − ze− [cm]
ThinRegular
ThickRandoms
37
Expected Impact
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
PLC suppression
Rescaling
Binding
LAD
Bou
ndF2
/Fr
eeF2
αs
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
38
I will cover:
1 Recoil-Tagged DIS
Testing the SRC-EMC connection
2 The ‘LAD’ Experiment
Large Acceptance Detector
3 The ‘BAND’ Experiment
Backward Angle Neutron Detector
39
DCJLab Hall B
CLAS12
BeamlineSVT
CTOF
SolenoidFTOF
PCal/ECal
LTCC
TorusHTCC
BAND will detect recoiling spectator neutrons.
scatteredelectron
jet from struck quark
Deuterium
Spectatorneutron
BAND
11 GeV e–
CLAS12
JLab Hall B
41
BAND will surround the upstream beamline.
42
BAND will surround the upstream beamline.
43
BAND Experiment Details
Experiment Backward Angle Neutron Detector
Experiment E12-11-003A
Approved for 90 days
parallel with DVCS
Run group I
Extended LD2 target
11 GeV e− beam
1035 cm−2s−1
Currently being developed
5 rows of panels of 21 bars
160◦–170◦
≈ 60% azimuthal coverage
44
BAND must respect several constraints.
Material in the n flight path
Only 160◦–170◦ is clear
Narrow “Keep-In” Zone
Must be thick to have
high-efficiency (> 30%)
Segmentation aids in pathlength resolution
. . . at the cost of light yield
A
B
C
D
C
Scintillator length● 3 groups for long bars● 1 group for short bars (500 mm)
18 rows & 5 layers (256 PMTs)● 232 PMTs main detector● 24 PMTs veto layer
Keep in zone
BAND design June 7th, 2017 (evening update)
Lengths inside keep in zone● ~28 mm from sides● ~72 mm from beampipe
Scintillator section:74x74mm2
45
We are studying PMT performance at MIT.
ANDOR
TriggerAND
60Co Source
Reference Bar
Test Bar
Efrain Segarra Adin Hrnjic help from Igor Korover
46
We are studying PMT performance at MIT.
0
100
200
300
400
500
600
0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
Tim
ere
solu
tion
[ps]
Energy deposit [MeV]
2 m bar, 5× 5 cm2 cross section
R7724-10R7724-100
R13435R13089
Each ps of resolution costs $0.225.
47
We have developed a detailed simulation of the
experiment.
1.2
1.3
1.4
1.5
1.6
1.7
0 0.2 0.4 0.6 0.8 1
αs
x ′
1.2
1.3
1.4
1.5
1.6
1.7
0 0.2 0.4 0.6 0.8 1
48
Analytic model for momentum resolution
δp/p ≈√
(pEcσt)2/2 + E4w2/12/(mnz)
0%
0.5%
1%
1.5%
2%
2.5%
250 300 350 400 450 500 550 600
150 ps PMTs
300 ps PMTs500 ps PMTs
Mom
entu
mre
solu
tion
Neutron momentum [MeV]
7 cm bars10 cm bars
49
Analytic model for momentum resolution
δp/p ≈√
(pEcσt)2/2 + E4w2/12/(mnz)
0%
0.5%
1%
1.5%
2%
2.5%
250 300 350 400 450 500 550 600
150 ps
300 ps
500 ps
Mom
entu
mre
solu
tion
Neutron momentum [MeV]
7 cm bars10 cm bars
50
Background will be higher at large x ′.
0
2000
4000
6000
8000
10000
12000
14000
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Q2 > 2 GeV2W ′ > 1.8 GeVSignal
Random Bkg.
Cou
nts
x ′
51
Even with background, we expect
good statistical precision.
0
2000
4000
6000
8000
10000
12000
1.3 1.35 1.4 1.45 1.5 1.55
Counts
αs
0.25 < x ′ < 0.35
1.2%
1.5%
2.1%
2.8%4.2%
0
2000
4000
6000
8000
10000
12000
1.3 1.35 1.4 1.45 1.5 1.55
52
Even with background, we expect
good statistical precision.
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1.3 1.35 1.4 1.45 1.5 1.55
Counts
αs
x ′ > 0.5
3.3%
4.4%
6.1%8.2%
11%
0
500
1000
1500
2000
2500
3000
3500
4000
4500
1.3 1.35 1.4 1.45 1.5 1.55
53
Expected Impact
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
PLC suppression
Rescaling
Binding
LAD
BANDBou
ndF2
/Fr
eeF2
αs
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
54
As the mechanical design is getting fixed
we are moving to a full Geant4 sim.
Efrain Segarra
Erez Cohen
55
The important points
1 Recoil tagging can test the
EMC-SRC connection.
2 LAD will detect recoil protons
in Hall C
3 BAND will detect recoil
neutrons in Hall B
ee'
recoilingspectator
56
The important points
1 Recoil tagging can test the
EMC-SRC connection.
2 LAD will detect recoil protons
in Hall C
3 BAND will detect recoil
neutrons in Hall B
scatteredelectron
jet from struck quark
Deuterium
LAD
11 GeV e–
SHMS
HMS
GEMsspectatorproton
JLab Hall C
57
The important points
1 Recoil tagging can test the
EMC-SRC connection.
2 LAD will detect recoil protons
in Hall C
3 BAND will detect recoil
neutrons in Hall B
scatteredelectron
jet from struck quark
Deuterium
Spectatorneutron
BAND
11 GeV e–
CLAS12
JLab Hall B
58
The important points
We will make a definitive statement about the role of virtuality in the
EMC effect.
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
PLC suppression
Rescaling
Binding
LAD
BANDBou
ndF2
/Fr
eeF2
αs
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1 1.1 1.2 1.3 1.4 1.5 1.6
59
The EMC effect is still a puzzle.
BAND and LAD will tell us if we are
putting the pieces in the right spot.
−0.1
0
0.1
0.2
0.3
0.4
0.5
01
23
45
6
2 H
3 He
4 He
9 Be
12 C
56 Fe
197 Au
EMCSlope(−dR/dxB)
SRC-pair d
ensity(a2)
60