DVCS at 6/12 GeV, and ideas for the EIC
DVCS at 6/12 GeV, and ideas for the EIC
DVCS at 6/12 GeV, and ideas for the EIC
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Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong>, <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>the</strong> <strong>EIC</strong><br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3 Aubière, France<br />
Electron-Ion Collider Workshop<br />
Mar 14-15, 2010<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 1
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Motiv<strong>at</strong>ion<br />
<strong>DVCS</strong> experimentally: interference with Be<strong>the</strong>-Heitler (BH)<br />
At leading twist:<br />
d 5 → σ −d 5 ← σ = Im (T BH · T DV CS )<br />
d 5 → σ +d 5 ← σ = |BH| 2 + Re (T BH · T DV CS ) + |DV CS| 2<br />
∫ +1<br />
T DV CS =<br />
∫ +1<br />
−1<br />
H(x, ξ, t)<br />
P dx<br />
−1 x − ξ<br />
} {{ }<br />
Access in helicity-independent cross section<br />
Carlos Muñoz Camacho<br />
H(x, ξ, t)<br />
dx<br />
x − ξ + iɛ + · · · =<br />
− iπ H(x = ξ, ξ, t) + . . .<br />
} {{ }<br />
Access in helicity-dependent cross-section<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 2
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Motiv<strong>at</strong>ion<br />
The <strong>DVCS</strong> program “worldwide”<br />
◮ HERMES <strong>at</strong> DESY:<br />
◮ Beam (BSA), charge (BCA) <strong>and</strong> transverse target (TSA)<br />
asymetries published<br />
◮ Several ongoing analysis + recoil detector installed 1 year<br />
be<strong>for</strong>e shutdown: results to come. . .<br />
◮ Hall A <strong>and</strong> Hall B partially overlapping, partially<br />
complementary, active programs:<br />
◮ Hall A: high accuracy, limited kinem<strong>at</strong>ics<br />
◮ Hall B: wide kinem<strong>at</strong>ic range, limited accuracy<br />
◮ Very different system<strong>at</strong>ics<br />
◮ COMPASS <strong>at</strong> CERN? (proposal prepar<strong>at</strong>ion underway)<br />
◮ The roadmap:<br />
◮ Early results (≈ 2001) from non-dedic<strong>at</strong>ed exp. (HERMES+CLAS)<br />
◮ First round of dedic<strong>at</strong>ed experiments in Halls A/B in 2004/5<br />
◮ Second round on 2008–2010<br />
◮ Compeling <strong>DVCS</strong> program in Halls A/B <strong>at</strong> 11 <strong>GeV</strong> (≈2013-15)<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 3
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Non-dedic<strong>at</strong>ed experiments<br />
HERMES<br />
27.5 <strong>GeV</strong> polarised<br />
e + /e − beam of HERA<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 4
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Non-dedic<strong>at</strong>ed experiments<br />
CLAS <strong>and</strong> HERMES (2001): beam spin asymmetries<br />
A LU : PRL 87, 182002 (2001)<br />
A UL : PRL 87, 182001 (2001)<br />
〈Q 2 , x B , −t〉 = 2.6 <strong>GeV</strong> 2 , 0.11, 0.27 <strong>GeV</strong> 2 0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
-0.1<br />
-0.2<br />
-0.3<br />
-0.4<br />
0 50 100 150 200 250 300 350<br />
φ (deg)<br />
A<br />
〈Q 2 , x B , −t〉 = 1.25 <strong>GeV</strong> 2 , 0.19, 0.19 <strong>GeV</strong> 2<br />
◮ Both results show, with a limited st<strong>at</strong>istics, a sin φ behaviour<br />
◮ Not fully exclusive<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 5
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Non-dedic<strong>at</strong>ed experiments<br />
Beam charge asymmetry (HERMES)<br />
A C<br />
0.2<br />
0.1<br />
0<br />
-0.1<br />
-0.2<br />
Integr<strong>at</strong>ed<br />
0 0.5 1 1.5 2 2.5 3<br />
|φ| (rad)<br />
cosφ<br />
A C<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
-0.1<br />
-0.2<br />
As a function of t<br />
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7<br />
-t (<strong>GeV</strong> 2 )<br />
Phys. Rev. D75, 011103 (2007)<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 6
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
0 0.5 0 0.2<br />
0 5 10<br />
0 0.5 0 0.2 0 5 10<br />
0 0.5 0 0.2 0 5 10<br />
0 0.5<br />
Non-dedic<strong>at</strong>ed experiments<br />
Beam charge asymmetry (2008)<br />
A C<br />
cosφ<br />
0.4<br />
0.2<br />
PRD75, 011103<br />
this work<br />
DD:Fac,D<br />
DD:Fac,no D<br />
DD:Reg,D<br />
DD:Reg,no D<br />
0<br />
A C<br />
cos(0φ)<br />
0<br />
-0.1<br />
A C<br />
cos(2φ)<br />
A C<br />
cos(3φ)<br />
0.1<br />
0<br />
-0.1<br />
0.1<br />
0<br />
-0.1<br />
0 0.2 0.4 0.6 0 0.1 0.2 0.3<br />
overall<br />
-t (<strong>GeV</strong> 2 )<br />
x B<br />
5 0 2 4 6 8 10<br />
Q 2 (<strong>GeV</strong> 2 )<br />
Carlos Muñoz Camacho<br />
JHEP 0806, 066 (2008)<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 7
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
0.2<br />
0<br />
-0.2<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
-0.15 -0.1 -0.05 0 0.05 0.1 0.15<br />
0 0.5<br />
0 0.2<br />
0 5 10<br />
0 0.5 0 0.2 0 5 10<br />
0 0.5<br />
0 5 10<br />
Non-dedic<strong>at</strong>ed experiments<br />
Transverse target spin asymmetry<br />
sin(φ-φ<br />
A s<br />
)<br />
UT<br />
0.2<br />
0<br />
-0.2<br />
8.1% scale uncertainty<br />
A UT, <strong>DVCS</strong><br />
J u =0.6<br />
0.4<br />
0.2<br />
A UT, I<br />
J u =0.6<br />
0.4<br />
0.2<br />
sin(φ-φ<br />
A s<br />
)cosφ<br />
UT<br />
0.2<br />
0<br />
cos(φ-φ<br />
A s<br />
)sinφ<br />
UT<br />
-0.2<br />
-0.4<br />
0.2<br />
0<br />
-0.2<br />
0 0.2 0.4 0.6<br />
overall<br />
-t (<strong>GeV</strong> 2 0 0.1 0.2 0.3 0 2 4 6 8 10<br />
)<br />
xB Q 2 (<strong>GeV</strong> 2 )<br />
JHEP 0806, 066 (2008)<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 8
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Non-dedic<strong>at</strong>ed experiments<br />
Recoil detector <strong>at</strong> HERMES<br />
Missing mass squared ep → eγX<br />
1000N/N DIS<br />
0.3 e +<br />
d<strong>at</strong>a<br />
-<br />
e d<strong>at</strong>a<br />
0.2<br />
MC sum<br />
elastic BH<br />
associ<strong>at</strong>ed BH<br />
semi-inclusive<br />
0.1<br />
0<br />
0 10 20 30<br />
2<br />
2<br />
M x (<strong>GeV</strong><br />
)<br />
Integr<strong>at</strong>ion window:<br />
−2.25 <strong>GeV</strong> 2 < M 2 x < 2.89 <strong>GeV</strong> 2<br />
◮ Not fully exclusive<br />
◮ Recoil detector oper<strong>at</strong>ed during last year of d<strong>at</strong>a taking<br />
◮ Analysis underway <strong>and</strong> results to come<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 9
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall A E00-110<br />
E00-110 experimental setup<br />
High Resolution Spectrometer<br />
100-channel scintill<strong>at</strong>or array<br />
132-block PbF 2 electromagnetic calorimeter<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 10
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall A E00-110<br />
Exclusivity<br />
Missing mass squared ep → eγX (E00-110)<br />
Raw H(e,e’γ)X Missing Mass 2 (after accidental subtraction).<br />
[ H(e,e’γ)X - H(e,e’γ)γY ]: Missing Mass 2<br />
H(e,e’γ)p<br />
H(e,e’γ)∆…<br />
+H(e,e’γp) sample,<br />
Normalized to H(e,e’γ)<br />
•••H(e,e’γp) simul<strong>at</strong>ion<br />
Exclusivity ensured by missing mass technique<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 11
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
2<br />
|BH+<strong>DVCS</strong>|<br />
2<br />
|BH|<br />
2<br />
|BH+<strong>DVCS</strong>|<br />
2<br />
- |BH|<br />
2<br />
2<br />
2<br />
2<br />
Hall A E00-110<br />
<strong>DVCS</strong> cross section in <strong>the</strong> valence region (Hall A: E00-110)<br />
◮ Helicity-dependent cross<br />
section ( → σ − ← σ ) <strong>at</strong><br />
Q 2 = 1.5, 1.9 <strong>and</strong> 2.3 <strong>GeV</strong> 2 .<br />
)<br />
4<br />
<strong>DVCS</strong> cross section (nb/<strong>GeV</strong><br />
0.04<br />
0.03<br />
0.02<br />
0<br />
0<br />
-0.02<br />
-0.03<br />
-0.04<br />
0.02<br />
0<br />
0<br />
-0.02<br />
< t > = - 0.33 <strong>GeV</strong><br />
E00-110<br />
Total fit<br />
Twist - 2<br />
90 180 270<br />
φ<br />
2<br />
0.04<br />
0.02<br />
0<br />
-0.02<br />
-0.04<br />
0.02<br />
0<br />
-0.02<br />
(deg)<br />
< t > = - 0.28 <strong>GeV</strong><br />
90 180 270<br />
2<br />
0.04<br />
0.02<br />
0<br />
-0.02<br />
-0.04<br />
0.02<br />
0<br />
-0.02<br />
φ (deg)<br />
< t > = - 0.23 <strong>GeV</strong><br />
90 180 270<br />
2<br />
0.04<br />
0.02<br />
0<br />
-0.02<br />
-0.04<br />
0.02<br />
0<br />
-0.02<br />
φ (deg)<br />
< t > = - 0.17 <strong>GeV</strong><br />
90 180 270<br />
2<br />
φ (deg)<br />
= 1.5 <strong>GeV</strong><br />
Q<br />
= 1.9 <strong>GeV</strong><br />
Q<br />
◮ Helicity-independent<br />
cross section ( → σ + ← σ ) <strong>at</strong><br />
Q 2 = 2.3 <strong>GeV</strong> 2 only .<br />
)<br />
4<br />
<strong>DVCS</strong> cross section (nb/<strong>GeV</strong><br />
0.02<br />
0<br />
-0.02<br />
0.1<br />
0.05<br />
0<br />
2<br />
< t > = - 0.33 <strong>GeV</strong><br />
E00-110<br />
Total fit<br />
Twist - 2<br />
E00-110<br />
2<br />
< t > = - 0.28 <strong>GeV</strong><br />
2<br />
< t > = - 0.23 <strong>GeV</strong><br />
2<br />
< t > = - 0.17 <strong>GeV</strong><br />
beam helicity-independent beam helicity-dependent<br />
90 180 270<br />
90 180 270<br />
90 180 270<br />
90 180 270<br />
φ (deg)<br />
φ (deg)<br />
φ (deg)<br />
φ (deg)<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> <strong>12</strong>
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall A E00-110<br />
E00-110 results<br />
)<br />
4<br />
<strong>DVCS</strong> cross section (nb/<strong>GeV</strong><br />
0.02 beam helicity-dependent<br />
0<br />
-0.02<br />
0.1<br />
0.05<br />
beam helicity-independent<br />
2<br />
|BH+<strong>DVCS</strong>|<br />
2<br />
|BH|<br />
0<br />
0 90 180 270 360<br />
φ (deg)<br />
(H, H ~ , E)<br />
I<br />
Im C<br />
5<br />
4<br />
3<br />
2<br />
1<br />
2<br />
2<br />
Q = 1.5 <strong>GeV</strong><br />
2<br />
2<br />
Q = 1.9 <strong>GeV</strong><br />
2<br />
2<br />
Q = 2.3 <strong>GeV</strong><br />
VGG model<br />
0<br />
0.15 0.2 0.25 0.3 0.35<br />
2<br />
-t (<strong>GeV</strong> )<br />
Twist-2: dominant contribution<br />
Contributions from BH 2 , <strong>DVCS</strong> 2<br />
<strong>and</strong> BH-<strong>DVCS</strong> interference<br />
Phys. Rev. Lett. 97, 262002 (2006)<br />
Physics Today, March 2007<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 13
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall A E00-110<br />
E00-110 results<br />
4<br />
3.5<br />
0.02 beam helicity-dependent<br />
3<br />
)<br />
4<br />
<strong>DVCS</strong> cross section (nb/<strong>GeV</strong><br />
0<br />
-0.02<br />
0.1<br />
0.05<br />
beam helicity-independent<br />
2<br />
|BH+<strong>DVCS</strong>|<br />
2<br />
|BH|<br />
0<br />
0 90 180 270 360<br />
φ (deg)<br />
2.5<br />
2<br />
1.5<br />
1<br />
0.5<br />
0<br />
1.4 1.6 1.8 2 2.2 2.4<br />
2 2<br />
Q (<strong>GeV</strong> )<br />
Twist-2: dominant contribution<br />
Contributions from BH 2 , <strong>DVCS</strong> 2<br />
<strong>and</strong> BH-<strong>DVCS</strong> interference<br />
Phys. Rev. Lett. 97, 262002 (2006)<br />
Physics Today, March 2007<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 13
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall A E03-106<br />
<strong>DVCS</strong> on <strong>the</strong> neutron: experiment E03-106 <strong>at</strong> JLab<br />
I exp<br />
)<br />
n<br />
Im(C<br />
3<br />
2<br />
1<br />
0<br />
-1<br />
-2<br />
-3<br />
-4<br />
LD 2 target (F2 n(t) ≫ F 1 n(t) !) J u=-0.4<br />
J d=-0.6<br />
J u=0.3<br />
J d=0.2<br />
J u=0.6<br />
J d=0.8<br />
2<br />
t (<strong>GeV</strong> )<br />
σ → − σ ← = Γ(A sin ϕ + . . . )<br />
-0.5 -0.45 -0.4 -0.35 -0.3 -0.25 -0.2 -0.15 -0.1<br />
Charged particle veto<br />
in front of scintill<strong>at</strong>or array<br />
A = F 1 (t)H +<br />
Carlos Muñoz Camacho<br />
x B<br />
[F 1 (t) + F 2 (t)]<br />
2 − x ˜H t<br />
−<br />
B 4M 2 · F 2(t) · E<br />
} {{ }<br />
Main contribution <strong>for</strong> neutron<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 14
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall A E03-106<br />
<strong>DVCS</strong> on <strong>the</strong> neutron: experiment E03-106 <strong>at</strong> JLab<br />
LD 2 target (F2 n(t) ≫ F 1 n (t) !)<br />
J d<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
JLab Hall A<br />
n-<strong>DVCS</strong><br />
Charged particle veto<br />
in front of scintill<strong>at</strong>or array<br />
0.2<br />
+ J u<br />
J d = 0.18<br />
5<br />
± 0.14<br />
-0<br />
-0.2<br />
L<strong>at</strong>tice QCDSF<br />
-0.4<br />
-0.6<br />
-0.8<br />
HERMES Preliminary<br />
p-<strong>DVCS</strong><br />
-1<br />
-1 -0.8 -0.6 -0.4 -0.2 -0 0.2 0.4 0.6 0.8 1<br />
J u<br />
σ → − σ ← = Γ(A sin ϕ + . . . )<br />
A = F 1 (t)H +<br />
Carlos Muñoz Camacho<br />
x B<br />
[F 1 (t) + F 2 (t)]<br />
2 − x ˜H t<br />
−<br />
B 4M 2 · F 2(t) · E<br />
} {{ }<br />
Main contribution <strong>for</strong> neutron<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 14
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall B E1-<strong>DVCS</strong><br />
BSA in a large kinem<strong>at</strong>ic domain (Hall B)<br />
2 2<br />
Q (<strong>GeV</strong> )<br />
0.2<br />
2<br />
-t = 0.28 <strong>GeV</strong><br />
A =<br />
→<br />
σ −<br />
←<br />
σ<br />
→<br />
σ +<br />
←<br />
σ<br />
≈<br />
α sin φ<br />
1 + β cos φ<br />
Simple models do not<br />
reproduce <strong>the</strong> d<strong>at</strong>a<br />
Carlos Muñoz Camacho<br />
4<br />
3<br />
2<br />
1<br />
0.1 0.2 0.3 0.4 0.5<br />
x B<br />
0.0<br />
-0.2<br />
0.2<br />
0.0<br />
-0.2<br />
Analysis of cross sections underway<br />
2<br />
-t = 0.49 <strong>GeV</strong><br />
0 90 180 270 360<br />
φ (deg)<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 15
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0 0.5 1 1.5<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
0.3<br />
0.2<br />
0 0.5 1 1.5<br />
0 0.5 1 1.5<br />
0.1<br />
0<br />
0 0.5 1 1.5<br />
Hall B E1-<strong>DVCS</strong><br />
BSA in a large kinem<strong>at</strong>ic domain (Hall B)<br />
0.3 0.10 < x < 0.15<br />
B<br />
)<br />
2<br />
(<strong>GeV</strong><br />
2<br />
α(t)<br />
0.2<br />
0.1<br />
Q<br />
0<br />
4<br />
0 0.5 1 1.5 2<br />
|t| (<strong>GeV</strong> )<br />
3<br />
A =<br />
→<br />
σ −<br />
←<br />
σ<br />
→<br />
σ +<br />
←<br />
σ<br />
≈<br />
α sin φ<br />
1 + β cos φ<br />
2<br />
Simple models do not<br />
reproduce <strong>the</strong> d<strong>at</strong>a<br />
1<br />
0.1 0.2 0.3 0.4 0.5<br />
x B<br />
Carlos Muñoz Camacho<br />
Analysis of cross sections underway<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 15
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall B<br />
Target spin asymmetry A UL (Hall B)<br />
Not dedic<strong>at</strong>ed result:<br />
0.4<br />
0.2<br />
A UL<br />
0<br />
-0.2<br />
-0.4<br />
-0.6<br />
0 50 100 150 200 250 300 350<br />
φ<br />
Degree<br />
Dedic<strong>at</strong>ed experiment took d<strong>at</strong>a in Hall B earlier this year<br />
Sensitivity to GPD ˜H<br />
O<strong>the</strong>r upcoming experiments (<strong>at</strong> 6 <strong>GeV</strong>):<br />
◮ More <strong>DVCS</strong> on unpolarized proton<br />
◮ <strong>DVCS</strong> on a transversely polarized target (conditionally approved)<br />
◮ <strong>DVCS</strong> on nuclei (He 4 )<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 16
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
E07-007: <strong>DVCS</strong>·BH – <strong>DVCS</strong> 2 separ<strong>at</strong>ion<br />
E07-007 (Hall A)<br />
σ(ep → epγ) = |BH| 2<br />
} {{ }<br />
+ I(BH · DV CS)<br />
} {{ }<br />
+ |DV CS| 2<br />
} {{ }<br />
Known to ∼ 1% Linear combin<strong>at</strong>ion of GPDs Bilinear combin<strong>at</strong>ion of GPDs<br />
<strong>DVCS</strong> cross section has a very rich azimuthal structure:<br />
◮ Azimuthal analysis allows <strong>the</strong> separ<strong>at</strong>ion of <strong>the</strong> different contributions to I<br />
if <strong>DVCS</strong> 2 is negligeble.<br />
◮ If <strong>DVCS</strong> 2 is important, I <strong>and</strong> <strong>DVCS</strong> 2 terms MIX in an azimuthal analysis.<br />
◮ The different energy dependence of I <strong>and</strong> <strong>DVCS</strong> 2 allow a full separ<strong>at</strong>ion.<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 17
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
E07-007: <strong>DVCS</strong>·BH – <strong>DVCS</strong> 2 separ<strong>at</strong>ion<br />
E07-007 (Hall A)<br />
σ(ep → epγ) = |BH| 2<br />
} {{ }<br />
+ I(BH · DV CS)<br />
} {{ }<br />
+ |DV CS| 2<br />
} {{ }<br />
Known to ∼ 1% Linear combin<strong>at</strong>ion of GPDs Bilinear combin<strong>at</strong>ion of GPDs<br />
<strong>DVCS</strong> cross section has a very rich azimuthal structure:<br />
◮ Azimuthal analysis allows <strong>the</strong> separ<strong>at</strong>ion of <strong>the</strong> different contributions to I<br />
if <strong>DVCS</strong> 2 is negligeble.<br />
◮ If <strong>DVCS</strong> 2 is important, I <strong>and</strong> <strong>DVCS</strong> 2 terms MIX in an azimuthal analysis.<br />
◮ The different energy dependence of I <strong>and</strong> <strong>DVCS</strong> 2 allow a full separ<strong>at</strong>ion.<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 17
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
E07-007: <strong>DVCS</strong>·BH – <strong>DVCS</strong> 2 separ<strong>at</strong>ion<br />
E07-007: Rosenbluth-like <strong>DVCS</strong> 2 –I separ<strong>at</strong>ion in Hall A<br />
E b =6.0 <strong>GeV</strong><br />
E b =3.64 <strong>GeV</strong><br />
◮ Clean separ<strong>at</strong>ion of BH-<strong>DVCS</strong> intereference term from pure <strong>DVCS</strong> 2<br />
◮ Scaling test on <strong>the</strong> real part of <strong>the</strong> <strong>DVCS</strong> amplitude<br />
◮ Rosenbluth separ<strong>at</strong>ion of σ L /σ T <strong>for</strong> ep → epπ 0<br />
BH<br />
4<br />
Simul<strong>at</strong>ed d<strong>at</strong>a<br />
D<br />
d σ<br />
4<br />
BH<br />
C<br />
(nb/<strong>GeV</strong> ) Simul<strong>at</strong>ed d<strong>at</strong>a<br />
<strong>DVCS</strong><br />
4 2<br />
C (F,F*)<br />
Re<br />
(nb/<strong>GeV</strong> )<br />
Fit<br />
dQ dx B<br />
dtdϕ<br />
I<br />
γγ<br />
Re<br />
1-σ<br />
Re<br />
d 4 σ (nb/<strong>GeV</strong> 4 Fit<br />
Re (C )<br />
I<br />
)<br />
Re (C I I<br />
I I<br />
γγ<br />
Re C<br />
+ ∆C )<br />
Re (C +∆ C )<br />
0.5<br />
I<br />
1-σ<br />
Re (C ) 3<br />
0<br />
eff 2.5<br />
2<br />
2<br />
2<br />
2<br />
=-0.33 <strong>GeV</strong> 2<br />
=-0.28 <strong>GeV</strong><br />
=-0.23 <strong>GeV</strong><br />
=-0.17 <strong>GeV</strong><br />
0.14 =-0.28 <strong>GeV</strong><br />
-0.5<br />
2<br />
=-0.23 0.14 I<br />
<strong>GeV</strong><br />
I<br />
2 2<br />
0.14<br />
0.14<br />
0.14<br />
0.14 Re (C +∆ C )<br />
=-0.17 <strong>GeV</strong><br />
-1<br />
0.14<br />
1.5<br />
0.<strong>12</strong> 0.<strong>12</strong> 3<br />
0.<strong>12</strong><br />
0.<strong>12</strong> 1<br />
0.<strong>12</strong> -1.5<br />
0.<strong>12</strong><br />
0.<strong>12</strong><br />
0.5<br />
0.1 2.5<br />
0.1<br />
0.1-2<br />
0.1<br />
0.1 0.1 0<br />
0.1<br />
2<br />
-2.5<br />
0.08<br />
0.08 0.08<br />
0.08 0.08 -0.5<br />
0.08<br />
1.5<br />
-3<br />
0.06<br />
0.06<br />
-0.35 -0.3 -0.25 -0.2<br />
0.06<br />
0.06<br />
-0.15<br />
-1<br />
-0.35 -0.3 -0.25 -0.2 -0.15<br />
0.06<br />
0.06<br />
1<br />
2<br />
2<br />
t (<strong>GeV</strong> )<br />
t (<strong>GeV</strong> )<br />
0.04 0.04<br />
0.04 0.04<br />
0.04<br />
0.5<br />
0.04<br />
0.04<br />
0.02<br />
0.02<br />
eff<br />
0.02<br />
<strong>DVCS</strong><br />
0.02 0<br />
0.02<br />
Re C<br />
0.02<br />
C<br />
0.02<br />
0<br />
0 5<br />
0<br />
40<br />
0 -0.5<br />
4 0<br />
0<br />
0<br />
270 ϕ (deg)<br />
360 -0.02<br />
-0.02<br />
0 0 90 90 180 180 270 ϕ (deg) 270 360 -0.02<br />
ϕ (deg)<br />
360<br />
0 -0.02<br />
0 90 90 180 270 180 ϕ (deg)<br />
360 -0.02<br />
3<br />
270 ϕ (deg)<br />
360<br />
0 90 -0.02<br />
0 180 30<br />
-0.2 -0.15<br />
-1<br />
-0.35 -0.3 -0.25 -0.2 -0.15<br />
90 270 ϕ (deg) 180 360<br />
270 ϕ (deg)<br />
360 -0.02<br />
γγ<br />
γ γ<br />
2<br />
γ γ<br />
γ γ<br />
0 90<br />
20<br />
2<br />
γγ<br />
1<br />
2<br />
t (<strong>GeV</strong> )<br />
t (<strong>GeV</strong> ) γ γ<br />
γ γ<br />
0.5 2<br />
=-0.28 <strong>GeV</strong><br />
0.5 2<br />
=-0.23 0 <strong>GeV</strong><br />
0.5 2 10<br />
=-0.17 <strong>GeV</strong><br />
0.5 2<br />
-1<br />
=-0.33 <strong>GeV</strong><br />
0.5 2<br />
=-0.28 <strong>GeV</strong><br />
0.5 2<br />
=-0.23 <strong>GeV</strong><br />
0.5 2<br />
<strong>DVCS</strong><br />
<strong>DVCS</strong><br />
0<br />
=-0.17 <strong>GeV</strong><br />
Simul<strong>at</strong>ed d<strong>at</strong>a 0.4<br />
C (F,F*)<br />
0.4-2C<br />
0.4<br />
I<br />
0.4 40Re (C)<br />
-3<br />
-0.35 0.4 -0.3 -0.25 -0.2 -0.15<br />
-10<br />
0.4 -0.35 -0.3 -0.25 -0.20.4<br />
-0.15<br />
Fit<br />
0.3<br />
I I<br />
0.3<br />
0.3 2<br />
2<br />
I Re (C+ ∆C )<br />
I I<br />
t (<strong>GeV</strong> )<br />
t (<strong>GeV</strong> )<br />
I<br />
1-σ Re C 30<br />
0.3<br />
Re (C )<br />
Re (C +∆ C )<br />
0.3<br />
I I<br />
0.3<br />
0.3<br />
0.2<br />
eff<br />
30.2<br />
Re (C +∆ C )<br />
0.2<br />
2<br />
<strong>GeV</strong><br />
0.1 2<br />
=-0.17 20 <strong>GeV</strong> 3<br />
2.5 E07-007 System<strong>at</strong>ic uncertainty<br />
0.1 0.2 0.08<br />
0.1 0.2<br />
0.1 0.2<br />
0.2<br />
0.06 102.5<br />
2<br />
1.5<br />
0.04 2<br />
0.1<br />
1<br />
0.02<br />
0 0.1<br />
0 0.1<br />
0.1<br />
0<br />
270 ϕ (deg)<br />
360 0 0 90 1.5<br />
180 270 ϕ (deg)<br />
360 0.5 E00-110: assuming <strong>DVCS</strong> 2 =0<br />
0 90 180 270 ϕ (deg)<br />
360 0 90 180 270 ϕ (deg)<br />
360<br />
-0.02<br />
γγ<br />
1<br />
0<br />
γ γ<br />
0<br />
0<br />
γ γ<br />
0<br />
γ γ<br />
0<br />
-0.2 -0.15<br />
-0.04 -10<br />
0 -0.06 90 -0.35 0.5<br />
180 270 -0.3<br />
ϕ (deg)<br />
360 -0.5 -0.25 0 90 -0.2 180 -0.15<br />
270 ϕ (deg)<br />
360 0 90 180 270 ϕ (deg)<br />
360 0 90<br />
-0.3 2<br />
2<br />
t (<strong>GeV</strong> ) -0.25-0.08<br />
-0.20<br />
-0.15<br />
-1<br />
-0.35 -0.3 -0.25<br />
γγ<br />
t (<strong>GeV</strong> ) -0.2 -0.15<br />
γ γ<br />
γ γ<br />
90 180 270 360<br />
-0.1<br />
ϕ (deg)<br />
0 90 180 270 2<br />
t (<strong>GeV</strong>ϕ<br />
) (deg)<br />
360<br />
2<br />
-0.5<br />
t (<strong>GeV</strong> )<br />
γ γ<br />
γ γ<br />
-0.2 -0.15<br />
-1<br />
eff -0.35 -0.3 -0.25 -0.2 <strong>DVCS</strong> -0.15<br />
2<br />
<strong>GeV</strong><br />
Re C 0.1 2<br />
Carlos Muñoz =-0.17 <strong>GeV</strong><br />
C<br />
2 Camacho<br />
2<br />
t (<strong>GeV</strong> ) 0.08<br />
40<br />
t (<strong>GeV</strong><br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
)<br />
0.06 Co-spokespersons: C.M.C., J. Roche, C. Hyde-Wright, P. Bertin<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> 0.04 <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 30<br />
18<br />
<strong>DVCS</strong>
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-A program<br />
JLab Hall A <strong>at</strong> 11 <strong>GeV</strong><br />
)<br />
2<br />
(<strong>GeV</strong><br />
2<br />
Q<br />
JLab<strong>12</strong> with 3, 4, 5 pass beam<br />
(6.6, 8.8, 11.0 <strong>GeV</strong> beam energy)<br />
<strong>DVCS</strong> measurements in Hall A/JLab<br />
10<br />
5<br />
0<br />
Carlos Muñoz Camacho<br />
2<br />
2<br />
W
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-A program<br />
Future possibilities<br />
◮ <strong>DVCS</strong> on <strong>the</strong> neutron <strong>at</strong> <strong>12</strong> <strong>GeV</strong><br />
◮ Extention to <strong>the</strong> full kinem<strong>at</strong>ic domain available with JLab <strong>at</strong> <strong>12</strong><strong>GeV</strong><br />
◮<br />
System<strong>at</strong>ic uncertainties improved<br />
◮ Recoil polarimetry (R+D)<br />
◮ A full <strong>DVCS</strong> program requires proton polariz<strong>at</strong>ion measurements<br />
◮<br />
◮<br />
Observables of proton recoil polariz<strong>at</strong>ion in ⃗ep → e⃗pγ<br />
are functionally equivalent to <strong>the</strong><br />
observables ⃗e⃗p → epγ <strong>for</strong> polarized targets<br />
Conceptual design of a large acceptance recoil polarimeter<br />
(longitudinal <strong>and</strong> transverse proton polariz<strong>at</strong>ion) under development<br />
◮ High luminosity (> 10 37 cm −2 s −1 ) 3 He target<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 20
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-A program<br />
Polarized 3 He target in JLab/Hall A<br />
◮ n lum. of 10 36 /cm 2 /s (14 <strong>at</strong>m × 40 cm)<br />
◮ ”Background” luminosity:<br />
◮ p in 3 He+entrance/exit windows<br />
◮ 10 37 /cm 2 /s total luminosity<br />
◮ Polariz<strong>at</strong>ion: 50%<br />
◮ Nuclear physics dilution factor 0.86 (d-st<strong>at</strong>e)<br />
◮ -2.8% p polariz<strong>at</strong>ion<br />
◮ Long. & Trans.<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 21
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-A program<br />
3 He target upgrade conjecture<br />
◮ Separ<strong>at</strong>e polariz<strong>at</strong>ion <strong>and</strong> target volumes<br />
◮ Increase throughput by a factor of 10 to 100<br />
◮ Cool <strong>and</strong>/or compress 3 He in target area by a factor of 10<br />
(10K <strong>at</strong> 10 <strong>at</strong>m × 20 cm)<br />
◮<br />
Rapid cycling of 3 He through target<br />
◮ Reduce depolariz<strong>at</strong>ion effect of target density, beam current,<br />
target walls<br />
◮ Replace thick glass with thin metallic walls<br />
◮ Neutron luminosity of 10 37 /cm 2 /s<br />
◮ Proton luminosity 2 · 10 37 cm 2 /s<br />
◮ Endcaps ≤ 10 37 /cm 2 /s<br />
◮ Target polariz<strong>at</strong>ion: 0.5 · (0.86 n − 0.028 p)<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 22
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-A program<br />
Neutron <strong>DVCS</strong> off a 3 He target<br />
⃗n(⃗e, e ′ γ)n via 3 ⃗ He(⃗e, e)X<br />
◮ Long or Trans normal polariz<strong>at</strong>ion<br />
◮ Target single spin cross sections<br />
◮ dσ ∼ sin ϕ (twist-2): Im[BH·<strong>DVCS</strong>]<br />
◮ Unpolarized protons in 3 He cancel<br />
◮ Target double spin<br />
◮ dσ ∼ c0 + c 1 cos ϕ: Re[BH 2 +(BH·<strong>DVCS</strong>)+<strong>DVCS</strong> 2 ]<br />
◮ Unpolarized protons cancel<br />
◮ Transverse sideways: sin ϕ → cos ϕ<br />
◮ All o<strong>the</strong>r “neutron” observables (total σ, beam-spin) have<br />
large incoherent proton contributions<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 23
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-A program<br />
Cross section projections (VGG <strong>at</strong> 10 37 cm −2 s −1 )<br />
Q 2 = 4 <strong>GeV</strong> 2 , x B = 0.36, k = 8.8 <strong>GeV</strong>,<br />
t min − t = 0.15 <strong>GeV</strong> 2 , 20 days<br />
Q 2 = 2.3 <strong>GeV</strong> 2 , x B = 0.36, k = 8.8 <strong>GeV</strong>, t = −0.26 <strong>GeV</strong> 2 , 10 days<br />
Polariz<strong>at</strong>ion sideways (‖) to (e, e ′ ) plane<br />
◮ 50%×80% polariz<strong>at</strong>ion<br />
Polariz<strong>at</strong>ion normal (⊥) to (e, e ′ ) plane<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 24
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-B program<br />
E<strong>12</strong>-06-119: <strong>DVCS</strong> with CLAS <strong>at</strong> 11 <strong>GeV</strong><br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 25
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-B program<br />
Beam spin asymmetry<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 26
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Hall-B program<br />
Target spin asymmetry<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 27
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Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Advantages<br />
<strong>DVCS</strong> with <strong>EIC</strong>: small x <strong>at</strong> high Q 2<br />
◮ Gluon GPDs<br />
£ <br />
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[ 1<br />
dxH(x, x)<br />
◮ Sum rules (ex: orbital angular momentum)<br />
∫ 1<br />
−1<br />
◮ Dispersion rel<strong>at</strong>ions<br />
Carlos Muñoz Camacho<br />
Re H(ξ) = PV<br />
dx x [H(x, ξ, 0) + E(x, ξ, 0)] = J<br />
∫ 1<br />
−1<br />
ξ − x − 1<br />
ξ + x<br />
]<br />
+ C<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 28
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Kinem<strong>at</strong>ics<br />
Collider vs fixed target kinem<strong>at</strong>ics<br />
◮ Fixed target: q ∗ , q <strong>and</strong> p ′ are all co-linear <strong>at</strong> t min<br />
◮ Collider: Boost γ P ≫ 1 along <strong>the</strong> beam direction<br />
(into collider frame)<br />
Non-parallel boost to q, q ′ <strong>and</strong> p ′<br />
Recoil proton <strong>at</strong> very small angles: t = −(4ξ 2 M 2 + t ⊥ )/(1 − 2ξ)<br />
tan θ p ′ ≃<br />
√ t⊥<br />
P (1−2ξ)<br />
Typically, we need to detect protons <strong>at</strong><br />
a few mrad (∼ 5) from <strong>the</strong> beamlines<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 29
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Projections<br />
Projections (Q 2 = 10 <strong>GeV</strong> 2 , x B = 0.05)<br />
◮ Projections using VGG model <strong>for</strong><br />
GPDs <strong>and</strong> L = 10 34 Hz/cm 2<br />
◮ Total cross-section larger than BH<br />
Plots by C. Hyde<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 30
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Projections<br />
Projections (Q 2 = 5 <strong>GeV</strong> 2 , x B = 0.02)<br />
◮ Total cross-section domin<strong>at</strong>ed by BH in this kinem<strong>at</strong>ics<br />
◮ Electron spin asymmetry particularly sensitive<br />
Plots by C. Hyde<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 31
Introduction Initial results Dedic<strong>at</strong>ed experiments Future 6 <strong>GeV</strong> <strong>12</strong> <strong>GeV</strong> <strong>EIC</strong> Conclusion<br />
Summary <strong>and</strong> conclusions<br />
JLab results:<br />
◮ Twist-2 dominance <strong>at</strong> rel<strong>at</strong>ive low Q 2 (a few <strong>GeV</strong> 2 )<br />
◮ Many polariz<strong>at</strong>ion observables needed: both target <strong>and</strong> beam<br />
◮ Different beam/collision energies needed<br />
◮ Absolute cross-sections better than asymmetries<br />
Opportunities with <strong>EIC</strong>:<br />
◮ Lower x <strong>at</strong> sufficiently high Q 2<br />
◮ Higher Q 2 lever arm to better underst<strong>and</strong>/h<strong>and</strong>le higher twists<br />
Challenges of <strong>EIC</strong>:<br />
◮ Luminosity (small cross-sections)<br />
◮ Very <strong>for</strong>ward recoil detection needed<br />
Carlos Muñoz Camacho<br />
LPC Clermont-Ferr<strong>and</strong>, CNRS/IN2P3<br />
<strong>DVCS</strong> <strong>at</strong> 6/<strong>12</strong> <strong>GeV</strong> <strong>and</strong> <strong>ideas</strong> <strong>for</strong> <strong>EIC</strong> 32