Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment - INSPIRE

Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering: Determined by the OLYMPUS Experiment

OLYMPUS

Collaboration

•

B.S. Henderson
(
- MIT
)

Nov 14, 2016

5 pages

Published in:

Phys.Rev.Lett. 118 (2017) 9, 092501

Published: Mar 3, 2017

e-Print:

1611.04685 [nucl-ex]

DOI:

10.1103/PhysRevLett.118.092501

Report number:

DESY-16-217

Experiments:

DESY-DORIS-OLYMPUS

View in:

reference search112 citations

Citations per year

Abstract: (Deutsches Elektronen-Synchrotron)

The OLYMPUS collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio,

\it R_{2 \gamma}

, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of

\approx

20° to 80°. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved GEM and MWPC detectors at 12°, as well as symmetric Møller/Bhabha calorimeters at 1:29°. A total integrated luminosity of

4.5 fb^{-1}

was collected. In the extraction of

\it R_{2\gamma}

, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of

\it R_{2\gamma}

, presented here for a wide range of virtual photon polarization 0:456 <

\epsilon

< 0:978, are smaller than hadronic two-photon exchange calculations predict, but are consistent with phenomenological models.

Note:

5 pages, 3 figures, 2 tables

References(46)

Figures(3)

[1]

Polarization transfer in the H-2(polarized-e, e-prime polarized-p) n reaction up to Q2 = 1.61-(GeV/c)2

B. Hu
(
- Hampton U.
)
,
M.K. Jones
(
- Old Dominion U.
)
,
P.E. Ulmer
(
- Old Dominion U.
)
,
H. Arenhovel
(
- Mainz U., Inst. Kernphys.
)
,
O.K. Baker
(
- Hampton U.
)

et al.

- Phys.Rev.C 73 (2006) 064004
•
e-Print:
- nucl-ex/0601025
•
DOI:
- 10.1103/PhysRevC.73.064004

[2]

The ratio of proton electromagnetic form factors via recoil polarimetry at Q2 = 1.13-(GeV/c)2

et al.

- Nucl.Phys.A 764 (2006) 261-273
•
DOI:
- 10.1016/j.nuclphysa.2005.09.012

[3]

Measurements of the elastic electromagnetic form-factor ratio mu(p) G(Ep) / G(Mp) via polarization transfer

O. Gayou
(
- Clermont-Ferrand U. and
- William-Mary Coll.
)
,
K. Wijesooriya
(
- Argonne
)
,
A. Afanasev
(
- North Carolina Central U. and
- Jefferson Lab
)
,
M. Amarian
(
- INFN, Rome and
- Rome, ISS
)
,
K. Aniol
(
- Cal State, L.A.
)

et al.

- Phys.Rev.C 64 (2001) 038202
•
DOI:
- 10.1103/PhysRevC.64.038202

[4]

Proton elastic form-factor ratios to Q2 = 3.5-GeV2 by polarization transfer

V. Punjabi
(
- Norfolk State U.
)
,
C.F. Perdrisat
(
- William-Mary Coll.
)
,
K.A. Aniol
(
- Cal State, L.A.
)
,
F.T. Baker
(
- Georgia U.
)
,
J. Berthot
(
- Clermont-Ferrand U.
)

et al.

- Phys.Rev.C 71 (2005) 055202,
- Phys.Rev.C 71 (2005) 069902 (erratum)
•
e-Print:
- nucl-ex/0501018
•
DOI:
- 10.1103/PhysRevC.71.055202

[5]

Proton G(E)/G(M) from beam-target asymmetry

Resonance Spin Structure

Collaboration

•

M.K. Jones
(
- Jefferson Lab
)

et al.

- Phys.Rev.C 74 (2006) 035201
•
e-Print:
- nucl-ex/0606015
•
DOI:
- 10.1103/PhysRevC.74.035201

[6]

Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to $Q^2$ = 8.5 GeV $^2$

A.J.R. Puckett
(
- MIT
)
,
E.J. Brash
(
- Christopher Newport U. and
- Jefferson Lab
)
,
M.K. Jones
(
- Jefferson Lab
)
,
W. Luo
(
- Lanzhou U.
)
,
M. Meziane
(
- William-Mary Coll.
)

et al.

- Phys.Rev.Lett. 104 (2010) 242301
•
e-Print:
- 1005.3419
•
DOI:
- 10.1103/PhysRevLett.104.242301

[7]

Polarization Transfer in the $^{4}He(\vec{e},e'\vec{p})^{3}H$ Reaction at $Q^2$ = 0.8 and 1.3 (GeV/c) $^2$

et al.

- Phys.Rev.Lett. 105 (2010) 072001
•
e-Print:
- 1002.2188
•
DOI:
- 10.1103/PhysRevLett.105.072001

[8]

Final Analysis of Proton Form Factor Ratio Data at $\mathbf{Q^2 = 4.0}$ , 4.8 and 5.6 GeV $\mathbf{^2}$

A.J.R. Puckett
(
- Los Alamos and
- Jefferson Lab
)
,
E.J. Brash
(
- Christopher Newport U. and
- Jefferson Lab
)
,
O. Gayou
(
- Clermont-Ferrand U. and
- William-Mary Coll.
)
,
M.K. Jones
(
- Jefferson Lab
)
,
L. Pentchev
(
- William-Mary Coll.
)

et al.

- Phys.Rev.C 85 (2012) 045203
•
e-Print:
- 1102.5737
•
DOI:
- 10.1103/PhysRevC.85.045203

[9]

MEASUREMENT OF THE RATIO OF THE PROTON FORM-FACTORS, G(E) / G(M), AT HIGH MOMENTUM TRANSFERS AND THE QUESTION OF SCALING

et al.

- Phys.Lett.B 31 (1970) 40-44
•
DOI:
- 10.1016/0370-2693(70)90015-8

[10]

Measurement of proton and neutron electromagnetic form-factors at squared four momentum transfers up to 3-GeV/c $^2$

W. Bartel
(
- DESY and
- Hamburg U.
)
,
F.W. Busser
(
- DESY and
- Hamburg U.
)
,
W.r. Dix
(
- DESY and
- Hamburg U.
)
,
R. Felst
(
- DESY and
- Hamburg U.
)
,
D. Harms
(
- DESY and
- Hamburg U.
)

et al.

- Nucl.Phys.B 58 (1973) 429-475
•
DOI:
- 10.1016/0550-3213(73)90594-4

[11]

Measurements of the electric and magnetic form-factors of the proton from Q2 = 1.75-GeV/c2 to 8.83-GeV/c**2

L. Andivahis
(
- American U.
)
,
Peter E. Bosted
(
- American U.
)
,
A. Lung
(
- American U.
)
,
L.M. Stuart
(
- UC, Davis and
- LLNL, Livermore
)
,
J. Alster
(
- Tel Aviv U.
)

et al.

- Phys.Rev.D 50 (1994) 5491-5517
•
DOI:
- 10.1103/PhysRevD.50.5491

[12]

Measurements of the proton elastic form-factors for 1-GeV/c2 <= Q2 <= 3-GeV/C**2 at SLAC

et al.

- Phys.Rev.D 49 (1994) 5671-5689
•
DOI:
- 10.1103/PhysRevD.49.5671

[13]

Measurements of electron proton elastic cross-sections for 0.4 < Q2 < 5.5 (GeV/c)2

E94110

Collaboration

•

M.E. Christy
(
- Hampton U.
)

et al.

- Phys.Rev.C 70 (2004) 015206
•
e-Print:
- nucl-ex/0401030
•
DOI:
- 10.1103/PhysRevC.70.015206

[14]

Precision Rosenbluth measurement of the proton elastic form-factors

I.A. Qattan
(
- Northwestern U. and
- Argonne
)
,
J. Arrington
(
- Argonne
)
,
R.E. Segel
(
- Northwestern U.
)
,
X. Zheng
(
- Argonne
)
,
K. Aniol
(
- Cal State, L.A.
)

et al.

- Phys.Rev.Lett. 94 (2005) 142301
•
e-Print:
- nucl-ex/0410010
•
DOI:
- 10.1103/PhysRevLett.94.142301

[15]

How to reconcile the Rosenbluth and the polarization transfer method in the measurement of the proton form-factors

- Phys.Rev.Lett. 91 (2003) 142303
•
e-Print:
- hep-ph/0306007
•
DOI:
- 10.1103/PhysRevLett.91.142303

[16]

Two photon exchange and elastic electron proton scattering

P.G. Blunden
(
- Manitoba U. and
- Jefferson Lab
)
,
W. Melnitchouk
(
- Jefferson Lab
)
,
J.A. Tjon
(
- Jefferson Lab and
- Maryland U.
)

- Phys.Rev.Lett. 91 (2003) 142304
•
e-Print:
- nucl-th/0306076
•
DOI:
- 10.1103/PhysRevLett.91.142304

[17]

Partonic calculation of the two photon exchange contribution to elastic electron proton scattering at large momentum transfer

Y.C. Chen
(
- Taiwan, Natl. Taiwan U.
)
,
A. Afanasev
(
- Jefferson Lab
)
,
S.J. Brodsky
(
- SLAC
)
,
C.E. Carlson
(
- Jefferson Lab and
- William-Mary Coll.
)
,
M. Vanderhaeghen
(
- Jefferson Lab and
- William-Mary Coll.
)

- Phys.Rev.Lett. 93 (2004) 122301
•
e-Print:
- hep-ph/0403058
•
DOI:
- 10.1103/PhysRevLett.93.122301

[18]

The Two-photon exchange contribution to elastic electron-nucleon scattering at large momentum transfer

Andrei V. Afanasev
(
- Jefferson Lab
)
,
Stanley J. Brodsky
(
- SLAC
)
,
Carl E. Carlson
(
- William-Mary Coll.
)
,
Yu-Chun Chen
(
- Taiwan, Natl. Taiwan U.
)
,
Marc Vanderhaeghen
(
- Jefferson Lab and
- William-Mary Coll.
)

- Phys.Rev.D 72 (2005) 013008
•
e-Print:
- hep-ph/0502013
•
DOI:
- 10.1103/PhysRevD.72.013008

[19]

Two-photon exchange in elastic electron-nucleon scattering

P.G. Blunden
(
- Manitoba U.
)
,
W. Melnitchouk
(
- Jefferson Lab
)
,
J.A. Tjon
(
- Jefferson Lab and
- Maryland U.
)

- Phys.Rev.C 72 (2005) 034612
•
e-Print:
- nucl-th/0506039
•
DOI:
- 10.1103/PhysRevC.72.034612

[20]

Delta resonance contribution to two-photon exchange in electron-proton scattering

S. Kondratyuk
(
- Manitoba U.
)
,
P.G. Blunden
(
- Manitoba U.
)
,
W. Melnitchouk
(
- Jefferson Lab
)
,
J.A. Tjon
(
- Jefferson Lab and
- Maryland U.
)

- Phys.Rev.Lett. 95 (2005) 172503
•
e-Print:
- nucl-th/0506026
•
DOI:
- 10.1103/PhysRevLett.95.172503

[21]

Radiative Corrections to Elastic and Inelastic e p and mu p Scattering

Luke W. Mo
(
- SLAC
)
,
Yung-Su Tsai
(
- SLAC
)

- Rev.Mod.Phys. 41 (1969) 205-235
•
DOI:
- 10.1103/RevModPhys.41.205

[22]

Radiative corrections to electron proton scattering

L.C. Maximon
(
- George Washington U.
)
,
J.A. Tjon
(
- Utrecht U. and
- Groningen, KVI
)

- Phys.Rev.C 62 (2000) 054320
•
e-Print:
- nucl-th/0002058
•
DOI:
- 10.1103/PhysRevC.62.054320

[23]

Structure function method applied to polarized and unpolarized electron-proton scattering: A solution of the GE(p)/GM(p) discrepancy

Yu.M. Bystritskiy
(
- Dubna, JINR
)
,
E.A. Kuraev
(
- Dubna, JINR
)
,
E. Tomasi-Gustafsson
(
- SPhN, DAPNIA, Saclay
)

- Phys.Rev.C 75 (2007) 015207
•
e-Print:
- hep-ph/0603132
•
DOI:
- 10.1103/PhysRevC.75.015207

[24]

Charge asymmetry for electron (positron)-proton elastic scattering at large angle

E.A. Kuraev
(
- Dubna, JINR
)
,
V.V. Bytev
(
- Dubna, JINR
)
,
S. Bakmaev
(
- Dubna, JINR
)
,
E. Tomasi-Gustafsson
(
- SPhN, DAPNIA, Saclay
)

- Phys.Rev.C 78 (2008) 015205
•
e-Print:
- 0710.3699
•
DOI:
- 10.1103/PhysRevC.78.015205

[25]

Measurement of the two-photon exchange contribution to the elastic $e^{\pm}p$ scattering cross sections at the VEPP-3 storage ring

I.A. Rachek
(
- Novosibirsk, IYF
)
,
J. Arrington
(
- Argonne
)
,
V.F. Dmitriev
(
- Novosibirsk, IYF and
- Novosibirsk State U.
)
,
V.V. Gauzshtein
(
- Tomsk Polytechnic U.
)
,
R.E. Gerasimov
(
- Novosibirsk, IYF and
- Novosibirsk State U.
)

et al.

- Phys.Rev.Lett. 114 (2015) 6, 062005
•
e-Print:
- 1411.7372
•
DOI:
- 10.1103/PhysRevLett.114.062005

1-25 of 46
1
2
25 / page