Quarkonium Production: From JLab to an EIC Sylvester Joosten - - PowerPoint PPT Presentation
This work is supported by DOE grant DE-FG02-94ER4084 Quarkonium Production: From JLab to an EIC Sylvester Joosten sylvester.joosten@temple.edu QCD Evolution 2018 (Santa Fe, NM) Quarkonium in electro- and photo-production l - Strong gluonic
Sylvester Joosten sylvester.joosten@temple.edu QCD Evolution 2018 (Santa Fe, NM)
This work is supported by DOE grant DE-FG02-94ER4084
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γ,γ* p p’ J/ψ,Υ l- l+ t
Strong gluonic interaction between color neutral
Minimal quark exchange Quarkonium as a probe to study the gluonic structure of the nucleon
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J/ψ photo-production:
Direct photo-production
Cornell ’75, SLAC ’75, CERN NA-14, FNAL E401, E687
Electro-production (quasi-real)
H1 and ZEUS
Ultra-peripheral pp collisions
LHCb ’14
Y(1s) photo-production:
Electro-production (quasi-real)
H1 and ZEUS
Ultra-peripheral pp collisions
LHCb ’15
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ψ J/
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Cornell '75 SLAC '75 CERN NA-14 FNAL E401 FNAL E687 *) γ H1 Combined ( *) γ ZEUS Combined ( LHCB '14 (UPC)
Y(1s) J/ψ
4 γ,γ* J/ψ,Υ l- l+ p p’ q q _
J/ψ photo-production:
Well constrained above W > 15 GeV
Dominated by t-channel 2-gluon exchange
Almost no data near threshold
Y(1s) photo-production:
Not much available
ZEUS measured 62 ± 12 events total!
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Cornell '75 SLAC '75 CERN NA-14 FNAL E401 FNAL E687 *) γ H1 Combined ( *) γ ZEUS Combined ( LHCB '14 (UPC)
Y(1s) J/ψ
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Y(1s) J/ψ
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Near Threshold:
Origin of proton mass, trace anomaly of the QCD energy- momentum tensor. Gluonic Van der Waals force, possible quarkonium-nucleon/ nucleus bound states Mechanism for quarkonium production
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Cornell '75 SLAC '75 CERN NA-14 FNAL E401 FNAL E687 *) γ H1 Combined ( *) γ ZEUS Combined ( LHCB '14 (UPC)
Y(1s) J/ψ
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Near Threshold:
Origin of proton mass, trace anomaly of the QCD energy- momentum tensor. Gluonic Van der Waals force, possible quarkonium-nucleon/ nucleus bound states Mechanism for quarkonium production
J/ψ program at Jefferson Lab Y(1s) production at an EIC
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ψ J/
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Cornell '75 SLAC '75 CERN NA-14 FNAL E401 FNAL E687 *) γ H1 Combined ( *) γ ZEUS Combined ( LHCB '14 (UPC)
Y(1s) J/ψ
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High Energies
Access Gluon GPD: Full 3D tomography of the gluonic structure of the nucleon L-T separation and the Q2 dependence of R for quarkonium production
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ψ J/
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Cornell '75 SLAC '75 CERN NA-14 FNAL E401 FNAL E687 *) γ H1 Combined ( *) γ ZEUS Combined ( LHCB '14 (UPC)
Y(1s) J/ψ
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J/ψ production at an EIC Y(1s) production at an EIC
High Energies
Access Gluon GPD: Full 3D tomography of the gluonic structure of the nucleon L-T separation and the Q2 dependence of R for quarkonium production
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S.J. Brodsky, et al., Phys.Lett. B498, 23-28 (2001)
Same as high energies (2-gluon)?
2-gluon
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S.J. Brodsky, et al., Phys.Lett. B498, 23-28 (2001)
Same as high energies (2-gluon)?
2-gluon 3-gluon
Maybe 3-gluon exchange dominant?
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S.J. Brodsky, et al., Phys.Lett. B498, 23-28 (2001)
Same as high energies (2-gluon)?
2-gluon 3-gluon
Or a partonic soft mechanism (power law 2-gluon form-factor)?
Frankfurt and Strikman., PRD66 (2002), 031502
partonic soft
Maybe 3-gluon exchange dominant?
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S.J. Brodsky, et al., Phys.Lett. B498, 23-28 (2001)
Same as high energies (2-gluon)?
2-gluon 3-gluon
Or a partonic soft mechanism (power law 2-gluon form-factor)?
Frankfurt and Strikman., PRD66 (2002), 031502
partonic soft Orders of magnitude difference 2-gluon fastest drop-off Drives required luminosity for threshold measurement
Maybe 3-gluon exchange dominant?
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10 15 20 25 (GeV)
γ
E
4 −
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3 −
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2 −
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1 −
10 1 10
2
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ψ J/
σ
Cornell '75 SLAC '75 SLAC '76 (Unpublished) 2-gluon fit
J/ψ
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4 −
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3 −
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2 −
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1 −
10 1 10
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*) γ H1 2000 ( *) γ ZEUS 2009 ( 2-gluon fit
Y(1s)
Smallest cross section drives required precision and luminosity Use 2-gluon estimate for experimental projections near threshold
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p p’ J/ψ,Υ J/ψ,Υ γ,γ* p p’ J/ψ,Υ
VMD VMD relates photo-production cross section to quarkonium-nucleon scattering amplitude Tψp.
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p p’ J/ψ,Υ J/ψ,Υ γ,γ* p p’ J/ψ,Υ
VMD
VMD relates photo-production cross section to quarkonium-nucleon scattering amplitude Tψp. Real part Tψp dominates near threshold Mostly constrained through dispersive relations, not data.
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Constituent quark mass from DSE and Lattice
Low momentum gluons attach to the current quark (DCSB) Gluon field accumulates ~300MeV/constituent quark Even in the chiral limit (mass from nothing)!
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Constituent quark mass from DSE and Lattice
Low momentum gluons attach to the current quark (DCSB) Gluon field accumulates ~300MeV/constituent quark Even in the chiral limit (mass from nothing)! The Higgs mechanism is largely irrelevant in “normal” matter!
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Access nucleon mass through trace of energy- momentum tensor (EMT) at zero momentum transfer
hP|T µ
µ |Pi = 2P µPµ = 2M 2 p
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Access nucleon mass through trace of energy- momentum tensor (EMT) at zero momentum transfer
T µ
µ =
˜ β(g) 2g G2 + X
q=u,d,s
mq(1 + γm) ¯ ψqψq
At low momentum transfer: heavy quarks decouple Trace Anomaly Light Quark Mass
hP|T µ
µ |Pi = 2P µPµ = 2M 2 p
Trace anomaly term dominant: “Proton mass result of the vacuum polarization induced by the presence of the proton.”
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Access nucleon mass through trace of energy- momentum tensor (EMT) at zero momentum transfer
T µ
µ =
˜ β(g) 2g G2 + X
q=u,d,s
mq(1 + γm) ¯ ψqψq
At low momentum transfer: heavy quarks decouple Trace Anomaly Light Quark Mass
hP|T µ
µ |Pi = 2P µPµ = 2M 2 p
Experimental access: Trace of EMT proportional to quarkonium-proton scattering amplitude Tψp Lattice QCD: Possible to evaluate <G2> directly
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Access nucleon mass through trace of energy- momentum tensor (EMT) at zero momentum transfer
T µ
µ =
˜ β(g) 2g G2 + X
q=u,d,s
mq(1 + γm) ¯ ψqψq
At low momentum transfer: heavy quarks decouple Trace Anomaly Light Quark Mass
hP|T µ
µ |Pi = 2P µPµ = 2M 2 p
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Matrix element of the QCD Hamiltonian in the rest frame gives the proton mass
HQCD = Z d3xT 00(0, ~ x) = Hq + Hm + Hg + Ha
Gluon Energy 34% Quark Mass 11% Quark Energy 33% Trace Anomaly 22%
Mq = 3 4 ✓ a − b 1 + γm ◆ M Mm = 4 + γm 4(1 + γm)bM Mg = 3 4(1 − a)M Ma = 1 4(1 − b)M
In leading order:
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Matrix element of the QCD Hamiltonian in the rest frame gives the proton mass
HQCD = Z d3xT 00(0, ~ x) = Hq + Hm + Hg + Ha
Gluon Energy 34% Quark Mass 11% Quark Energy 33% Trace Anomaly 22%
Mq = 3 4 ✓ a − b 1 + γm ◆ M Mm = 4 + γm 4(1 + γm)bM Mg = 3 4(1 − a)M Ma = 1 4(1 − b)M
In leading order:
a(μ) related to PDFs, well constrained b(μ) related to quarkonium- proton scattering amplitude Tψp near-threshold
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“… 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 )
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“… 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
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Color neutral objects: gluonic Van der Waals force
At threshold, spin-averaged scattering amplitude related to s- wave scattering length aψp
Binding Bψp can be derived from aψp
Tψp = 8π(M + Mψ)aψp
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Estimates between 0.05-0.30 fm, corresponding to Bψp < 20 MeV LQCD: Bψp < 40 MeV Recent fit to existing data in a dispersive framework:
aψp ~ 0.05 fm (Bψp ~ 3 MeV)
Color neutral objects: gluonic Van der Waals force
At threshold, spin-averaged scattering amplitude related to s- wave scattering length aψp
Binding Bψp can be derived from aψp
Tψp = 8π(M + Mψ)aψp
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Estimates between 0.05-0.30 fm, corresponding to Bψp < 20 MeV LQCD: Bψp < 40 MeV Recent fit to existing data in a dispersive framework:
aψp ~ 0.05 fm (Bψp ~ 3 MeV)
Color neutral objects: gluonic Van der Waals force
At threshold, spin-averaged scattering amplitude related to s- wave scattering length aψp
Binding Bψp can be derived from aψp
Tψp = 8π(M + Mψ)aψp
Photo-production near threshold constrained through dispersion relations, not data Threshold experiments needed!
16 Slide from O. Gryniuk
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, hence aψp and Bψp
J/ψ B-H
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Possible explanations for LHCb observations:
LHCb: 2 new charmed “pentaquark” (Pc) states alternative: kinematic enhancements through anomalous triangle singularity (ATS)
Lui X-H, et al., PLB 757 (2016), p231 (and references therein)
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Possible explanations for LHCb observations:
LHCb: 2 new charmed “pentaquark” (Pc) states alternative: kinematic enhancements through anomalous triangle singularity (ATS)
Photo-production ideal tool to distinguish between both explanations
if Pc real states, also created in photo-production kinematic enhancement through ATS not possible
Lui X-H, et al., PLB 757 (2016), p231 (and references therein) Wang Q., et al., PRD 92-3 (2015) 034022-7 (and references therein)
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Possible explanations for LHCb observations:
LHCb: 2 new charmed “pentaquark” (Pc) states alternative: kinematic enhancements through anomalous triangle singularity (ATS)
Photo-production ideal tool to distinguish between both explanations
if Pc real states, also created in photo-production kinematic enhancement through ATS not possible
Pc(4450) translates to narrow peak around Eγ = 10 GeV
Lui X-H, et al., PLB 757 (2016), p231 (and references therein) Wang Q., et al., PRD 92-3 (2015) 034022-7 (and references therein)
JLab perfect place for this measurement!
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A B C D JLab is the ideal laboratory to measure J/ψ near threshold, due to luminosity, resolution and energy reach!
CEBAF: High-luminosity continuous electron beam 4 Experimental Halls 11GeV at Hall A, B and C 12GeV at Hall D
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First J/ψ at JLab! Expected daily yield: ~5-10 J/ψ
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First data taken with run-group A this Spring! Expected daily yield: ~45 J/ψ for 130 days
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50μA electron beam at 10.6 GeV for 11 days 9% copper radiator 15cm liquid hydrogen target total 10% RL Detect J/ψ decay leptons in coincidence
Bremsstrahlung photon energy fully constrained
positron in SHMS
Z.-E. Meziani, S. Joosten et al., arXiv:1609.00676 [hep-ex]
To beamdump 1 3
D Q Q Q
Incident beam Hydrogen target
e- Detector Stacks:
Tracking/ Timing:
2 2 4
Particle ID:
9% Cu Radiator
D Q
S H M S
HB
Argon/Neon Cerenkov HGC S1XS1Y AGC DC1 DC2 S2X S2Y LGC A1 C4F10 Cerenkov1 2 2 3 1 4
Q Q
HMS
e+
electron in HMS
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50μA electron beam at 10.6 GeV for 11 days 9% copper radiator 15cm liquid hydrogen target total 10% RL Detect J/ψ decay leptons in coincidence
Bremsstrahlung photon energy fully constrained
positron in SHMS
Z.-E. Meziani, S. Joosten et al., arXiv:1609.00676 [hep-ex]
To beamdump 1 3
D Q Q Q
Incident beam Hydrogen target
e- Detector Stacks:
Tracking/ Timing:
2 2 4
Particle ID:
9% Cu Radiator
D Q
S H M S
HB
Argon/Neon Cerenkov HGC S1XS1Y AGC DC1 DC2 S2X S2Y LGC A1 C4F10 Cerenkov1 2 2 3 1 4
Q Q
HMS
e+
electron in HMS
High-impact experiment …will run February 2019!
22 Pc s − channel γ J/ ψ (a) Pc u − channel γ J/ ψ (b)
P’ P P P’
s-channel u-channel
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Cross section depends on coupling of Pc to (J/ψ, p) channel
Pc s − channel γ J/ ψ (a) Pc u − channel γ J/ ψ (b)
P’ P P P’
s-channel u-channel
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) θ cos( 1 − 0.8 − 0.6 − 0.4 − 0.2 − 0.2 0.4 0.6 0.8 1 Arbitrary Units 1 2 3 4
Ψ t-channel J/ 5/2+
c
P 3/2-
c
P 5/2-
c
P 3/2+
c
P
Cross section depends on coupling of Pc to (J/ψ, p) channel J/ψ angular distribution differs between t-channel and s(u)-channel
Pc s − channel γ J/ ψ (a) Pc u − channel γ J/ ψ (b)
P’ P P P’
s-channel u-channel
dσ d cos θJ/ψ (γp → Pc → J/ψp)
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) θ cos( 1 − 0.8 − 0.6 − 0.4 − 0.2 − 0.2 0.4 0.6 0.8 1 Arbitrary Units 1 2 3 4
Ψ t-channel J/ 5/2+
c
P 3/2-
c
P 5/2-
c
P 3/2+
c
P
Cross section depends on coupling of Pc to (J/ψ, p) channel J/ψ angular distribution differs between t-channel and s(u)-channel
Pc s − channel γ J/ ψ (a) Pc u − channel γ J/ ψ (b)
P’ P P P’
s-channel u-channel Leverage angular dependence to maximize sensitivity at low coupling!
dσ d cos θJ/ψ (γp → Pc → J/ψp)
2 settings:
“SIGNAL” (#1) to maximize S/B “BACKGROUND” (#2) to precisely determine t-channel J/ψ cross section
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[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 100 200
Ψ t-channel J/ 3/2- (5.0% coupling)
c
P 5/2+ (5.0% coupling)
c
P sum 9 day estimate
[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 50 100 150
Ψ t-channel J/ 3/2- (5.0% coupling)
c
P 5/2+ (5.0% coupling)
c
P sum 2 day estimate
SIGNAL (9 days)
t-channel: 120 events 5/2+: 881 events 3/2-: 266 events
BACKGROUND (2 days)
t-channel: 682 events 5/2+: 204 events 3/2-: 26 events
2+9 days of beam time at 50μA 5/2+ peak dominates the spectrum
26x reduction in t-channel background rate
Background measurement will provide first-hand information about t-channel production near threshold
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[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 100 200
Ψ t-channel J/ 3/2- (5.0% coupling)
c
P 5/2+ (5.0% coupling)
c
P sum 9 day estimate
[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 50 100 150
Ψ t-channel J/ 3/2- (5.0% coupling)
c
P 5/2+ (5.0% coupling)
c
P sum 2 day estimate
SIGNAL (9 days)
t-channel: 120 events 5/2+: 881 events 3/2-: 266 events
BACKGROUND (2 days)
t-channel: 682 events 5/2+: 204 events 3/2-: 26 events
coupling [%] 1 1.5 2 2.5 3 ] σ Sensitivity [n 1 10
Projected Sensitivity limit σ 5
According to formalism from Wang Q., et al., PRD 92-3 (2015) 034022-7
2+9 days of beam time at 50μA 5/2+ peak dominates the spectrum
26x reduction in t-channel background rate
Background measurement will provide first-hand information about t-channel production near threshold
Significance > 20σ!
(in case of 5% coupling)
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γ/γ∗ + N → N + J/ψ
3μA electron beam at 11 GeV for 50 days 11 GeV beam 15cm liquid hydrogen target Ultra-high luminosity (43.2 ab-1) General purpose large- acceptance spectrometer Symmetric acceptance for electrons and positrons Electro-production Real photo-production through bremsstrahlung in the target cell ATHENNA Collaboration
and references therein
25 [GeV]
γ
E 10 [nb] σ
4 −
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Cornell 75 SLAC 75 SLAC 76 (Unpublished) CERN 87 t-channel (2-gluon) (4450)
c
t-channel + P SoLID 50 days 3-fold (4450)
c
SoLID 50 days 3-fold with P SoLID 50 days 2-fold (4450)
c
SoLID 50 days 2-fold with P
ψ Total Elastic Electro-and Photo- production of J/
]
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| [GeV
min
|t-t 1 2 3 4 5 ]
/dt [nb GeV σ d
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2-gluon (b: 1.13GeV 4.15 GeV < W < 4.25 GeV
]
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min
|t-t 1 2 3 4 5 ]
/dt [nb GeV σ d
3 −
10
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SoLID 50 days 3-fold )
2-gluon (b: 1.13GeV 4.25 GeV < W < 4.35 GeV
Photo-production
2-fold coincidence + recoil proton t-channel J/ψ rate: 1627 per day Advantage over electro-production Energy reach in charmed pentaquark region High rate
Electro-production
3-fold coincidence (3 leptons) t-channel J/ψ rate: 86 per day Advantage over photo-production: Less background Closer to threshold
ATHENNA Collaboration
Sensitivity below 10-3 nb !
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GlueX HALL D HMS+SHMS HALL C CLAS 12 HALL B SoLID HALL A J/ψ Rate (photo-prod.) 5-10/day #1: 13/day #2: 341/day 45/day 1627/day J/ψ Rate (electro-prod.) 86/day Experiment E12-16-007 E12-12-001 E12-12-006 PAC days 9+2 130 50 When? Ongoing Early 2019 Ongoing ~10 years?
Exciting times for near-threshold J/ψ production!
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EIC ZEUS (2009) H1 (2000) 2-gluon fit
EIC Simulation (10GeV on 100GeV) )
s
cm
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(116 days @ 10
100 fb
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< 1 GeV
2
Q
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Υ(1s) production possible at threshold!
Provides measure for universality, complimentary to threshold J/ψ program at JLab12 Is there a “beautiful” pentaquark?
Sensitivity down to ~10-3 nb!
Quasi-real production at an EIC Using nominal EIC detector (consistent with white paper) Both electron and muon channel Fully exclusive reaction Can go to near-threshold region
29 γ* J/ψ,Υ p p’ x + ξ x - ξ t
⇢(|~ bT |, xV ) = Z d2~ ∆T (2⇡)2 ei~
∆T~ bT |hHgi|(t = ~
∆2
T )
|hHgi|(t) / r dσ dt (t)/dσ dt (t = 0)
Hard scale: Q2 + M 2
V
Modified Bjorken-x: xV = Q2 + M 2
V
2p · q
average unpolarized gluon GPD related to t-dependent cross section (LO) Fourier transform: transverse gluonic profile
29 γ* J/ψ,Υ p p’ x + ξ x - ξ t
⇢(|~ bT |, xV ) = Z d2~ ∆T (2⇡)2 ei~
∆T~ bT |hHgi|(t = ~
∆2
T )
|hHgi|(t) / r dσ dt (t)/dσ dt (t = 0)
Hard scale: Q2 + M 2
V
Modified Bjorken-x: xV = Q2 + M 2
V
2p · q
average unpolarized gluon GPD related to t-dependent cross section (LO) Fourier transform: transverse gluonic profile
Remarks:
Simplest possible GPD extraction Intrinsic systematic uncertainty due to extrapolation outside of measured t-range NLO effects could be significant Corrections expected to be smaller for Y(1s) than for J/ψ
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Gluon GPD in fine bins of xV and Q2 (from EIC white paper)
Normalized average gluon density t-spectra
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Gluon GPD in fine bins of xV and Q2 (from EIC white paper)
Normalized average gluon density t-spectra
Only possible at an EIC: from the valence region deep into the sea!
10
4 −10
3 −10
2 −10
1 −10 1
Vx
210 ]
2[GeV
2 Υ+ M
2Q 10
210
310
EIC Simulation (10GeV on 100GeV) )
s
cm
34(116 days @ 10
100 fb
y = 0.8
b
T
[ f m ]
0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00
x
V
5e-02 1e-01 2e-01 5e-01
xVF(xV,bT) [1/fm2]
1 2 3 4 5 6
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Average gluon density:
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0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ]
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1 −10 1 10 ]
/dt [nb GeV σ d
EIC Simulation (10GeV on 100 GeV)data (projected) Υ t-channel (exponential) t-channel (variations)
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ]
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1 −10 1 10 ]
/dt [nb GeV σ d
EIC Simulation (10GeV on 100 GeV)data (projected) Υ t-channel (exponential) t-channel (variations)
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ]
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2 −10
1 −10 1 10 ]
/dt [nb GeV σ d
EIC Simulation (10GeV on 100 GeV)data (projected) Υ t-channel (exponential) t-channel (variations)
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ]
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1 −10 1 10 ]
/dt [nb GeV σ d
EIC Simulation (10GeV on 100 GeV)data (projected) Υ t-channel (exponential) t-channel (variations)
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ]
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1 −10 1 10 ]
/dt [nb GeV σ d
EIC Simulation (10GeV on 100 GeV)data (projected) Υ t-channel (exponential) t-channel (variations)
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ]
210
2 −10
1 −10 1 10 ]
/dt [nb GeV σ d
EIC Simulation (10GeV on 100 GeV)data (projected) Υ t-channel (exponential) t-channel (variations)
t-spectrum
Nominal EIC detector 10x more luminosity Electron and muon channels
1 − 0.5 − 0.5 1 )
ψ CM, J/ e
θ cos( 10 20 ) [nb]
ψ CM, J/ e
θ /dcos( σ d
]: 9.6 - 10.0
2
[GeV
2 ψ J/
+ M
2
Q ]: 15.6 - 19.6
2
[GeV
2 ψ J/
+ M
2
Q ]: 24.6 - 29.6
2
[GeV
2 ψ J/
+ M
2
Q
< 0.25
V
0.16 < x 5 GeV on 100 GeV (nominal)
EIC 10fb
32
W(cos θCM) = 3 8
00 + (1 − 3r04 00) cos2 θCM
R ≡ L T = 1 ✏ r04
00
1 − r04
00
s-channel helicity conservation (SCHC): J/ψ takes on (virtual) photon polarization Angular distribution of the decay pair
33
Quarkonium production an important tool to study the gluonic fields in the nucleon Threshold production of quarkonium can shed light
and proton mass Possible to study “charming” (and “beautiful”?) pentaquarks At high energies: 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
35
eRHIC (BNL) JLEIC (JLab) Nominal parameters relevant to quarkonium production:
(Consistent with accelerator/detector specs from white-paper for J/ψ production)
10 GeV electron beam on 100 GeV proton beam in range of both designs Luminosity: 100 fb-1 Acceptance (conservative!): Leptons: pseudo-rapidity |η| < 5 Recoil proton: scattering angle θ > 2 mrad Resolution: Angular < 0.5 mrad Momentum < 1%
d dQ2dydt = ΓT (1 + ✏R)Ddγ dt R = ✓AM 2
V + Q2
AM 2
V
◆n1 − 1
Dipole Pomeron Model.” PRD 67 (7), 2003. doi:10.1103/ PhysRevD.67.074023
model.” PRD80:116001, 2009"
D = ✓ M 2
V
M 2
V + Q2
◆n2
389-398
proton interactions 470 GeV", ZPC74 (1997) 237-261.
HERMES” DESY-Thesis 2001-018 (2001)
HERMES Data”, DESY-Thesis (2004)
dσγ dt
“Photoproduction of Charm Near Threshold.” Physics Letters B 498 (1-2): 23–28. doi:10.1016/S0370-2693(00)01373-3.
W(cos θCM) = 3 8
00 + (1 − 3r04 00) cos2 θCM
and J/psi mesons at HERA, EPJ-C 6-4 (1999)
mesons at HERA (2002)
R = 1 ✏ r04
00
1 − r04
00
38
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
39
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!
40
k p p’ l+ l- l- l+ p’ p k
[GeV]
γ
E 8 8.5 9 9.5 10 10.5 11 11.5 12 [nb] σ
2 −
10
1 −
10 1 Cornell 75 SLAC 76 (Unpublished) t-channel (2-gluon) Bethe-Heitler
Estimated using calculations from Pauk and Vanderhaeghen Constant background < 10% of the t-channel J/ψ Can be exactly calculated and controlled for Interference negligible at the Pc(4450) peak
Not an issue!
Pauk V and Vanderhaeghen M, PRL 115(22) (2015) 221804
41
[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 200 400
Ψ t-channel J/ 3/2+ (5.0% coupling)
c
P 5/2- (5.0% coupling)
c
P sum 9 day estimate
]
2
t [GeV 6 − 5 − 4 − 3 − 2 − 1 − 1 2 Counts 100 200 300
Ψ t-channel J/ 3/2+ (5.0% coupling)
c
P 5/2- (5.0% coupling)
c
P sum 9 day estimate
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!)
42
[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 500 1000 1500 2000
Ψ t-channel J/ 3/2+ (5.0% coupling)
c
P 5/2- (5.0% coupling)
c
P sum 2 day estimate
]
2
t [GeV 6 − 5 − 4 − 3 − 2 − 1 − 1 2 Counts 500 1000 1500
Ψ t-channel J/ 3/2+ (5.0% coupling)
c
P 5/2- (5.0% coupling)
c
P sum 2 day estimate
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
43
coupling [%] 1 1.5 2 2.5 3 ] σ Sensitivity [n 1 10
Projected Sensitivity limit σ 5
[GeV]
γ
E 9 9.5 10 10.5 11 11.5 12 Counts 10 20
Ψ t-channel J/ 3/2- (1.3% coupling)
c
P 5/2+ (1.3% coupling)
c
P sum 9 day estimate
sensitivity calculated using a Δ-log-likelihood formalism 5 standard deviation level of sensitivity starting from 1.3% coupling!