This work is supported by DOE grant DE-FG02-94ER4084

Heavy Quarkonium Production: From JLab to an EIC Sylvester Joosten [email protected]

Overview: 1. Near-threshold J/ψ production 2. A Search for the LHCb Pentaquarks in Hall C 3. 12 GeV J/ψ Experiments at JLab 4. Heavy Quarkonium at an EIC

INT, August 30, 2017 Heavy Quarkonium as a Probe

Near Threshold: Study color Van der Waals force, possible charmonium- nucleon/nucleus bound states Access trace anomaly of the QCD energy-momentum tensor, study the origin of mass Disentangle real from imaginary part of the amplitude through the interference with Bethe-Heitler J/ψ program at Jefferson Lab

e−

c γ High Energies (far from threshold) J/Ψ Dominated by 2-gluon exchange c

Access the gluon GPD at an EIC e+

P’ P

2 S. Joosten Near-threshold J/ψ production The Proton Mass is an Emergent Phenomenon

M. S. Bhagwat et al., Phys. Rev. C 68, 015203 (2003) M 2 p T ↵ p /h | ↵ | i Proton mass related to trace of QCD energy-momentum tensor Has two distinct components: Quark mass term Conformal (trace) anomaly

Trace anomaly related to real part of heavy quarkonium- nucleon scattering amplitude Event in the chiral limit, the gluon field Dominant contribution near accumulates ~300 MeV/constituent threshold! quark. The Higgs mechanism is largely irrelevant in normal matter!

4 S. Joosten The Origin of Mass is a Hot Topic!

“… The vast majority of the nucleon’s mass is due to quantum fluctuations of quark- antiquark pairs, the gluons, and the energy associated with quarks moving around at close to the speed of light. …”

(The 2015 Long Range Plan for Nuclear Science )

JLab will play a leading role: Access Trace anomaly through elastic J/ψ production near threshold 5 S. Joosten Do J/ψ and protons attract each other?

O. Gryniuk and M. Vanderhaeghen, Phys. Rev. D 94, 074001 (2016) Color neutral objects: “QCD Van der Waals force” Characterized by s-wave scattering length aψp Current estimates ranging from 0.05-0.30 fm, corresponding to

Bψp < 20 MeV

LQCD: Bψp < 40 MeV At threshold: tot 4⇡a2 p ⌘ p Fit to existing data: aψp = 0.05 fm

(Bψp = 3 MeV)

Photo-production near threshold constrained with dispersion relations

Threshold data needed to really constrain Bψp 6 S. Joosten Alternative way to extract the scattering length aψp

Interference between elastic J/ψ production near threshold and Bethe-Heitler Forward-backward asymmetry near the J/ψ invariant mass peak

Sensitive to real part of the scattering amplitude, and therefore aψp and Bψp

J/ψ

B-H

7 Slide from O. Gryniuk S. Joosten What do we (not) know about J/ψ photo-production?

S.J. Brodsky, et al., Phys.Lett. B498, 23-28 (2001)

2-gluon 3-gluon J/ψ threshold region crucially important. BUT… almost no data available! Need new data to study production mechanism near threshold: Do we need a 3-gluon model instead of a 2-gluon model? Are there any resonances or bounds states hiding near threshold? Is there any sub-threshold production?

8 S. Joosten 12 GeV J/ψ experiments at JLab

Hall C/SHMS+HMS: Hall D/GlueX: Approved experiment to search for First J/ψ at JLab! the LHCb pentaquark (E12-16-007)

Hall A/SoLID: Hall B/CLAS12: Approved future high-luminosity Approved experiment to measure experiment to measure J/ψ in TCS + J/ψ in photo-production photo- and electro-production (E12-12-001) (E12-12-006)

9 S. Joosten A Search for the LHCb Pentaquarks in Hall C The LHCb charmed “pentaquark” Pc is a hot topic

Since the CERN press release from July 14, 2015…

441 citations in 2 years!

Discovery inspired large number of theoretical work, touching our community and beyond

11 S. Joosten Discovery of the LHCb charmed “pentaquark” Pc

⇤ KpJ/ b ! Aaij, R, et. al (LHCb) PRL 115-7 (2015)

⇤ ⇤⇤J/ (Kp)J/ b ! ! 2 Pc states needed to ⇤b KPc K(pJ/ ) describe results ! !

narrow: Pc(4450) narrow: Pc(4450) (12 σ)

wide: Pc(4380) spin/parity either: wide: Pc(4390) (9σ) 5/2+, 3/2- (most likely!) 5/2-, 3/2+ 3/2-, 5/2+

12 S. Joosten charmed “pentaquark” in photo-production

Common explanations:

LHCb: 2 new charmed “pentaquark” (Pc) states alternative: kinematic enhancements through Lui X-H, et al., PLB 757 (2016), p231 anomalous triangle singularity (ATS) (and references therein) Photo-production ideal tool to distinguish between both explanations

if Pc real states, also created in photo-production kinematic enhancement through ATS not possible in Wang Q., et al., PRD 92-3 (2015) 034022-7 photo-production (and references therein)

Pc(4450) translates to narrow peak around Eγ = 10 GeV

JLab is the ideal laboratory for the measurement, due to luminosity, resolution and energy reach at threshold!

13 S. Joosten J/ψ photo-production: what do we know?

− e Cross section well constrained above c γ J/Ψ 100 GeV c Almost no data near-threshold e+ Resolution of the existing P’ P measurements too low t-channel 2 of the 3 lowest points unpublished! Brodsky S J, et al., PLB 498-1 (2001), p23 103 103 [nb] [nb] Cornell 75 σ σ 102 102 SLAC 75 SLAC 76 (Unpub.) Cornell 75 2-gluon fit 10 SLAC 75 10 SLAC 76 (Unpublished) CERN NA14 1 FNAL E401 1 FNAL E687 * −1 H1 Combined (γ ) −1 10 * 10 ZEUS Combined (γ ) * LHCb 2014 (γ ) 2 Pc? 10−2 10− 10 102 103 104 105 106 10 15 20 145 S. Joosten Eγ [GeV] Eγ [GeV] Resonant J/ψ production through Pc decay

γ γ J/ψ J/ψ Cross section depends on

P c P c coupling to (J/ψ, p) channel

s − channel u − channel J/ψ angular distribution P’ P P’ P s-channel(a) u-channel(b) depends on Pc spin/parity

1 4 3% coupling t-channel J/Ψ

[nb] Cornell 75

σ P 5/2+ SLAC 76 (Unpublished) c 0.8 Pc 3/2- t-channel (2-gluon) 3 Pc 5/2- Pc 5/2+ (3% coupling) Arbitrary Units Pc 3/2+ 0.6 Pc 3/2- (3% coupling) sum 2 0.4

1 0.2

0 0 −1 −0.8 −0.6 −0.4 −0.2 0 0.2 0.4 0.6 0.8 1 8 8.5 9 9.5 10 10.5 11 11.5 12 cos(θ) d Eγ [GeV] (p P J/ p) Leverage cos(θ) dependence to d cos ✓ ! c ! J/ maximize S/B at low coupling! Wang Q., et al., PRD 92-3 (2015) 034022-7 15 S. Joosten Experiment E12-16-007 in Hall C at JLab

D

A B C

Approved by PAC44 Rated A/“high impact”

16 S. Joosten Experiment E12-16-007 in Hall C at JLab

positron in+ SHMS 50μA electron beam at 11 GeV e

LGC S2Y 9% copper radiator S2X 4 A1 C HG

Y XS1 S1 v 2 DC Cerenko 15cm liquid hydrogen target F10 C4 DC1 1 2

AGC

renkov Ce total 10% RL on Argon/Ne 2 D 1 Detect J/ψ decay leptons in 3 SHMSQ Q coincidence Q 9% Cu Radiator HB Bremsstrahlung photon To beamdump energy fully constrained Incident beam

Hydrogen Stacks: Q Detector target Q Tracking/ Timing: HMS Q 1. Drift Chambers 2. Hodoscopes D 1 Particle ID: 2 3 3. Gas erenkov Standard Hall C Detector Package, 4 4. Lead Glass Calorimeter 2 - Radiator Well Understood electrone in HMS

17 S. Joosten Maximizing the sensitivity

Use HMS and SHMS to maximize Pc

4 signal over t-channel background t-channel J/Ψ

Pc 5/2+ Pc 3/2- Run with 2 settings: 3 Pc 5/2- Arbitrary Units ”SIGNAL” Setting (9 days): Pc 3/2+ 2 minimizes accidentals and

maximizes signal/background: 1 HMS: 34o, 3.25 GeV electrons o 0 SHMS: 13 , 4.5 GeV positrons −1 −0.8 −0.6 −0.4 −0.2 0 0.2 0.4 0.6 0.8 1 ”BACKGROUND” Setting: cos(θ) (2 days): precise determination of the t-channel background HMS: 20o, 4.75 GeV electrons SHMS: 20o, 4.25 GeV positrons Bottom line: can run SOON and FAST 18 S. Joosten Projected results for “SIGNAL” Setting

assuming 5% coupling (value favored by existing

photo-production data) Wang Q., et al., PRD 92-3 (2015) 034022-7 t-channel: 120 events 9 days of beam time at 50μA 5/2+: 881 events 5/2+ peak dominates the spectrum 3/2-: 266 events

t-channel J/Ψ t-channel J/Ψ

Counts P 3/2- (5.0% coupling) Counts P 3/2- (5.0% coupling) 200 c c Pc 5/2+ (5.0% coupling) Pc 5/2+ (5.0% coupling) sum 200 sum 150 9 day estimate 9 day estimate

100 100

50

0 0 −6 −5 −4 −3 −2 −1 0 1 2 9 9.5 10 10.5 11 11.5 12 2 t [GeV ] Eγ [GeV] Only 9 days! Significance > 20σ! 19 S. Joosten Projected results for “BACKGROUND” Setting

2 days of beam time at 50μA

able to separate 5/2+ from t-channel at low Eγ will provide first-hand information about t-channel production near threshold t-channel: 682 events assuming 5% coupling (value favored by existing 5/2+: 204 events photo-production data) 3/2-: 26 events

150 300 t-channel J/Ψ t-channel J/Ψ

Counts Pc 3/2- (5.0% coupling) Counts Pc 3/2- (5.0% coupling)

Pc 5/2+ (5.0% coupling) Pc 5/2+ (5.0% coupling) sum sum 100 200 2 day estimate 2 day estimate

100 50

0 0 −6 −5 −4 −3 −2 −1 0 1 2 9 9.5 10 10.5 11 11.5 12 2 t [GeV ] Eγ [GeV] Only 2 days! 20 S. Joosten Sensitivity for Discovery

sensitivity calculated using a Δ-log-likelihood formalism 5 standard deviation level of sensitivity starting from 1.3% coupling!

Projection for

] 1.3% coupling σ t-channel J/Ψ

Counts P 3/2- (1.3% coupling) 10 c Pc 5/2+ (1.3% coupling) 20 sum Sensitivity [n 9 day estimate

Projected Sensitivity 10

5σ limit 1

0 1 1.5 2 2.5 3 9 9.5 10 10.5 11 11.5 12 coupling [%] Eγ [GeV]

21 S. Joosten Impact on the world data for J/ψ production

"SIGNAL" Setting (9 days) [nb]

σ "BACKGROUND" Setting (2 days) 3 Cornell 75 SLAC 76 (Unpublished) J/ with P (5% coupling) ψ c

2

1

0 8 8.5 9 9.5 10 10.5 11 11.5 12

Eγ [GeV]

22 S. Joosten E12-16-007 Summary

High impact result will

either confirm Pc resonance, or strongly exclude its existence Strong sensitivity to the coupling down to 1.3% Will provide knowledge about J/ψ production (absolute cross section!) near threshold Helps future experimental endeavors at CLAS12 and SoLID Only need 11 days Straightforward experiment, able to run early with a standard Hall C package

23 S. Joosten 12 GeV J/ψ experiments at JLab 12 GeV J/ψ experiments at JLab

Hall C/SHMS+HMS: Hall D/GlueX: Approved experiment to search for First J/ψ at JLab! the LHCb pentaquark (E12-16-007)

Hall A/SoLID: Hall B/CLAS12: Approved future high-luminosity Approved experiment to measure experiment to measure J/ψ in TCS + J/ψ in photo-production photo- and electro-production (E12-12-001) (E12-12-006)

25 S. Joosten Hall B/CLAS12 Experiment E12-12-001

26 S. Joosten J/ψ experiment E12-12-006 at SoLID

e−

c γ /⇤ + N N + J/ J/Ψ ! c

Threshold J/ψ production, probing e+

P’ strong color field in the nucleon, QCD P trace anomaly (important for proton mass budget) Ultra-high luminosity (43.2 ab^-1) Will allow for high-resolution multidimensional access to the J/ψ production cross section Precision measurement of the charm- pentaquarks, if they exist

27 S. Joosten J/ψ experiment E12-12-006 at SoLID

Total Elastic Electro-and Photo- production of J/ψ 10

1 Photo-production Cornell 75 −1 2-fold coincidence + recoil proton 10 SLAC 75

[nb] SLAC 76 (Unpublished) t-channel J/ψ rate: 1627 per day σ CERN 87 10−2 t-channel (2-gluon) t-channel + Pc(4450) Pc(4450) rate: 927 per day SoLID 50 days 3-fold −3 SoLID 50 days 3-fold with P (4450) (5% coupling) 10 c SoLID 50 days 2-fold SoLID 50 days 2-fold with P (4450) c 10−4 Electro-production 10 E [GeV] 3-fold coincidence (3 leptons) γ 4.15 GeV < W < 4.25 GeV 4.25 GeV < W < 4.35 GeV 10−1 10−1 t-channel J/ψ rate: 86 per day SoLID 50 days 3-fold SoLID 50 days 3-fold 2-gluon (b: 1.13GeV-2) 2-gluon (b: 1.13GeV-2) ] ]

Pc(4450) rate: 36 per day -2 -2 (5% coupling) 10−2 10−2 /dt [nb GeV /dt [nb GeV σ σ d d 10−3 10−3

0 1 2 3 4 5 0 1 2 3 4 5 |t-t | [GeV2] |t-t | [GeV2] min min 28 S. Joosten 12 GeV J/ψ experiments at JLab

GlueX HMS+SHMS CLAS 12 SoLID HALL D HALL C HALL B HALL A

J/ψ Rate #1: 13/day 5-10/day 45/day 1627/day (photo-prod.) #2: 341/day

J/ψ Rate 86/day (electro-prod.)

Experiment E12-16-007 E12-12-001 E12-12-006

9+2 days PAC 130 days 50 days high-impact

When? Now Soon! Few years 5-10 years

29 TimeS. Joosten Heavy Quarkonium at an EIC US Based EIC: The Machines eRHIC (BNL) JLEIC (JLab)

First polarized electron-proton/ion collider in the world First electron-nucleus collider in the world Both make use of existing infrastructure

31 S. Joosten Quarkonia at an EIC complimentary to JLab

J/ψ production at high W tool for gluon imaging not possible at JLab12 Access to Q2 dependence close to J/ψ threshold

Υ production possible at threshold and high W Important cross check for universality due to smaller higher-order corrections For gluon GPDs extracted with J/ψ at the EIC For J/ψ threshold physics at JLab12 Is there a “bottom pentaquark?”

32 S. Joosten Accelerator and detector parameters Nominal parameters relevant to DVMP: eRHIC (BNL) (Consistent with accelerator/ detector specs from white-paper) 5 GeV electron beam on 100 GeV proton beam in range of both designs Luminosity: 10-100 fb-1 Acceptance: Leptons: pseudo-rapidity |η| < 5 JLEIC (JLab) Recoil proton: scattering angle θ > 2 mrad Resolution: Angular < 0.5 mrad Momentum < 1% Only looking at electron-positron channels! 33 S. Joosten J/ψ photo-production cross section

Quasi-real production at an EIC Simulation based on a 2-gluon fit to the world data Fully exclusive reaction Can go close to threshold 2 W-range limited by the 10 5 GeV on 100 GeV electron acceptance 10 SLAC 75 1 SLAC 76 (Unpublished) Cornell 75 [nb]

σ −1 CERN 87 10 E687 ZEUS (2000) 10−2 H1 (2003) EIC 10fb-1 (Q2 < 0.5 GeV2) 2-gluon (b: 4.5 GeV-2) 10−3 10 W [GeV]

34 S. Joosten Spatial Imaging of gluon density with J/ψ

2 2 2 Hard scale: Q + M d ~ T ~ ~ J/ ⇢( ~b ,x )= eiT bT H (t = ~ 2 ) | T | V (2⇡)2 |h gi| T Z 2 2 Q + MJ/ Fourier transform Modified Bjorken-x: x = V 2p q · Normalized average gluon density: -2 ρ(b, xV) [fm ] 0.16 < xV < 0.25 3D t-spectrum 102 0.16 < xV < 0.25 5 GeV on 100 GeV EIC 10fb-1 (nominal) 2 10 Q

]

-2 1 []

/dt [nb GeV

σ d 10−1 - 2 2 2 Q + M [GeV ]: 10.0 - 16.0 J/ψ [] Q2 + M2 [GeV2]: 16.0 - 25.0 J/ψ - −2 Q2 + M2 [GeV2]: 25.0 - 30.0 10 J/ψ [] 0 0.2 0.4 0.6 0.8 1 1.2 1.4 - -t [GeV2] b [fm] Only possible at an EIC: 35 from the valence region deep into the sea! S. Joosten L-T separation and the Q2 dependence of R 04 3 04 04 2 1 r00 (cos ✓CM)= 1+r +(1 3r ) cos ✓CM R = W 8 00 00 04 ✏ 1 r00

Angular distribution of the decay pair

0.16 < xV < 0.25 20 5 GeV on 100 GeV EIC 10fb-1 (nominal) Can extract R in 3D or even 4D ) [nb]

ψ Test s-channel helicity 10 e CM, J/

θ conservation (SCHC) Precise measurement of the Q2 /dcos( σ d 0 Q2 + M2 [GeV2]: 9.6 - 10.0 J/ψ dependence of R Q2 + M2 [GeV2]: 15.6 - 19.6 J/ψ Q2 + M2 [GeV2]: 24.6 - 29.6 J/ψ −1 −0.5 0 0.5 1 e cos(θCM, J/ψ)

36 S. Joosten Y photo-production cross section

Quasi-real production at an EIC Simulation based on a 2-gluon fit to the (sparse) world data Fully exclusive reaction Can go to near-threshold region 1 5 GeV on 100 GeV

10−1 Y cross section ~100x [nb] lower than J/ψ. σ 10−2 ZEUS (2009) H1 (2000) Reasonable precision with EIC 100fb-1 (Q2 < 0.5 GeV2) -2 −3 2-gluon (b: 4.5 GeV ) 10x more luminosity 10 102 W [GeV]

37 S. Joosten Spatial Imaging of gluon density with Y 2 2 2 Hard scale: Q + M d ~ T ~ ~ ⌥ ⇢( ~b ,x )= eiT bT H (t = ~ 2 ) | T | V (2⇡)2 |h gi| T Z Q2 + M 2 Fourier transform Modified Bjorken-x: x = ⌥ V 2p q · Normalized average gluon density: -2 ρ(b, xV) [fm ] 0.16 < xV < 0.25 3D t-spectrum 0.16 < xV < 0.25 1 5 GeV on 100 GeV EIC 100fb-1 (nominal) 2 Q

]

-2 10−1 −2 [] 10

/dt [nb GeV

σ d - 2 2 2 Q + M [GeV ]: 89.9 - 95.9 10−3 Υ [] 2 2 2 Q + MΥ [GeV ]: 95.9 - 104.9 2 2 2 - Q + MΥ [GeV ]: 104.9 - 109.9 −4 [] 10 0 0.2 0.4 0.6 0.8 1 1.2 1.4 - -t [GeV2] b [fm]

Y a viable tool38 to check Universality! S. Joosten Conclusion

Heavy Quarkonium production an important tool to study the gluons fields in the nucleon Threshold production of heavy quarkonium can shed light on the trace anomaly and proton mass Possible to study charm (and bottom?) pentaquarks At high W: possible to access gluon GPDs Can test universality by comparing Y to J/ψ results JLab12 and the EIC are (will be) perfectly positioned to significantly contribute to these topics

This work is supported by DOE grant DE-FG02-94ER4084

39 S. Joosten BACKUP SLIDES d d = (1 + ✏R)D dQ2dydt T dt

2 2 n1 • Martynov, et. al., “Photoproduction of Vector Mesons in the Soft AMV + Q Dipole Pomeron Model.” PRD 67 (7), 2003. doi:10.1103/ R = 1 PhysRevD.67.074023 AM 2 • R. Fiore et al., "Exclusive Jpsi electroproduction in a dual ✓ V ◆ model.” PRD80:116001, 2009"

• A. Airapetian et al, "Exclusive Leptoproduction of rho0 Mesons on Hydrogen at Intermediate W Values", EPJ C 17 (2000) 2 n2 389-398 MV • Adams et al., "Diffractive production of ρ0 mesons in muon– D = proton interactions 470 GeV", ZPC74 (1997) 237-261. M 2 + Q2 • M Tytgat, "Diffractive production of ρ0 and ω vector mesons at ✓ V ◆ HERMES” DESY-Thesis 2001-018 (2001) • P. Liebing, “Can the Gluon Polarization be Extracted From HERMES Data”, DESY-Thesis (2004)

d • Brodsky, S J, E Chudakov, P Hoyer, and J M Laget. 2001. “Photoproduction of Charm Near Threshold.” Physics Letters B dt 498 (1-2): 23–28. doi:10.1016/S0370-2693(00)01373-3. Angular dependence of the decay lepton pair in the J/psi Helicity frame

3 (cos ✓ )= 1+r04 +(1 3r04) cos2 ✓ W CM 8 00 00 CM

• FORMULA FOR TWO FERMION DECAY • J. Breitweg et al. (ZEUS), Exclusive electro-production of rho0 and J/psi mesons at HERA, EPJ-C 6-4 (1999) • Chekanov et al. (ZEUS), Exclusive photo production of J/psi mesons at HERA (2002) • K. Schilling et. Al, Nucl.Phys. B 61, 381 (1973)

1 r04 R = 00 • Extract r04 from the measured angular distribution ✏ 1 r04 • Directly related to R! 00 Alternate Pc Assumption (Setting “SIGNAL”)

Alternate (5/2-, 3/2+) Pc assumption

assuming 5% coupling for the (5/2-, 3/2+) Pc assumption 9 days of beam time at 50μA 5/2- peak dominates the spectrum (even larger than the 5/2+ peak!)

t-channel J/Ψ t-channel J/Ψ

Counts P 3/2+ (5.0% coupling) Counts P 3/2+ (5.0% coupling) 300 c c Pc 5/2- (5.0% coupling) Pc 5/2- (5.0% coupling) sum 400 sum 9 day estimate 9 day estimate 200

200 100

0 0 −6 −5 −4 −3 −2 −1 0 1 2 9 9.5 10 10.5 11 11.5 12 2 t [GeV ] Eγ [GeV]

43 S. Joosten Alternate Pc Assumption (“BACKGROUND” Setting)

Alternate (5/2-, 3/2+) Pc assumption 2 days of beam time at 50μA

able to separate 5/2- from t-channel at low Eγ will provide first-hand information about t-channel production near threshold

assuming 5% coupling for the (5/2-, 3/2+) Pc assumption

1500 t-channel J/Ψ 2000 t-channel J/Ψ

Counts Pc 3/2+ (5.0% coupling) Counts Pc 3/2+ (5.0% coupling)

Pc 5/2- (5.0% coupling) Pc 5/2- (5.0% coupling) sum 1500 sum 1000 2 day estimate 2 day estimate

1000

500 500

0 0 −6 −5 −4 −3 −2 −1 0 1 2 9 9.5 10 10.5 11 11.5 12 2 t [GeV ] Eγ [GeV] 44 S. Joosten Background: Bethe-Heitler pair production

+ k k p e ep + ! l+ l - - Not an issue! l l

Estimated using p p’ p p’ calculations from Pauk and Vanderhaeghen 1 [nb] Constant background σ < 10% of the t-channel J/ψ

Can be exactly calculated 10−1 Cornell 75 and controlled for SLAC 76 (Unpublished) Interference negligible at t-channel (2-gluon) Bethe-Heitler the Pc(4450) peak 10−2

Pauk V and Vanderhaeghen M, PRL 115(22) (2015) 221804 8 8.5 9 9.5 10 10.5 11 11.5 12

Eγ [GeV] 45 S. Joosten Background: inelastic t-channel (γp -> J/ψpπ)

Threshold at 9 GeV

Reconstructed photon energy Erc is ~1 GeV too low less than 30% of the elastic t-channel background

Contaminates the 8 GeV < Erc < 9.7 GeV range for a photon end-point energy of 10.7 GeV

not an issue for the Pc(4450) (Erc > 9.7GeV)!

not an issue for the Pc!

46 S. Joosten Photon Energy Reconstruction

Can unambiguously reconstruct the initial photon energy from the reconstructed J/ψ momentum and energy Assumptions: photon beam along the z-axis proton target at rest 2 final state particles: a proton and a J/ψ

47 S. Joosten Properties of the Hall C Spectrometers

48 S. Joosten Run Plan for E12-16-007

Total Beam Time Request: 11 days (264h), 10.7 GeV (or 11 GeV), 50μA, Hall C Run Plan: 1. t-channel “BACKGROUND”: 40 hours 2. radiator out: 8 hours (longer if needed) 3. main “SIGNAL” measurement: 216 hours

11 days, standard equipment!

49 S. Joosten