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Title: Final analysis of proton form factor ratio data at Q2 = 4.0, 4.8, and 5.6 GeV2

Journal Article · · Physical Review C, Nuclear Physics

Recently published measurements of the proton electromagnetic form factor ratio R = μp GEp/GMp at momentum transfers Q2 up to 8.5 GeV2 in Jefferson Lab Hall C deviate from the linear trend of previous measurements in Jefferson Lab Hall A, favoring a slower rate of decrease of R with Q2. While statistically compatible in the region of overlap with Hall A, the Hall C data hint at a systematic difference between the two experiments. This possibility was investigated in a reanalysis of the Hall A data. We find that the original analysis underestimated the background in the selection of elastic events. The application of an additional cut to further suppress the background increases the results for R, improving the consistency between Halls A and C.

Research Organization:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Contributing Organization:
Jefferson Lab Hall A Collaboration
Grant/Contract Number:
AC05-84ER40150
OSTI ID:
1119671
Alternate ID(s):
OSTI ID: 1098705
Report Number(s):
JLAB-PHY-11-1318; DOE/OR/23177-1477; arXiv:1102.5737; PRVCAN; TRN: US1600814
Journal Information:
Physical Review C, Nuclear Physics, Vol. 85, Issue 4; Related Information: Authored by The Jefferson Lab Hall A Collaboration; ISSN 0556-2813
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 145 works
Citation information provided by
Web of Science

References (161)

P -wave baryons in the quark model journal December 1978
Role of color neutrality in nuclear physics: Modifications of nucleonic wave functions journal August 1996
High Q 2 behavior of the electromagnetic form factors in the relativistic hypercentral constituent quark model journal December 2010
Shape of the nucleon journal January 2006
Pure S -wave covariant model for the nucleon journal January 2008
Precision measurement of the neutron magnetic form factor journal September 1994
Scaling laws for large-momentum-transfer processes journal March 1975
Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to Q 2 = 8.5 GeV 2 journal June 2010
Electromagnetic form factors of the proton at squared four-momentum transfers between 10 and 50 fm−2 journal April 1971
Scaling limit of deeply virtual compton scattering journal July 1996
Publisher's Note: Proton elastic form factor ratios to Q 2 = 3.5 GeV 2 by polarization transfer [Phys. Rev. C 71, 055202 (2005)] journal June 2005
Deeply virtual Compton scattering journal June 1997
Perturbative QCD Analysis of the Nucleon’s Pauli Form Factor F 2 ( Q 2 ) journal August 2003
Nucleon form factors from generalized parton distributions journal September 2005
Proton G E / G M from beam-target asymmetry journal September 2006
Dispersion-theoretical analysis of the nucleon electromagnetic form factors journal January 1996
Measurements of elastic electron-proton scattering at large momentum transfer journal July 1993
Dispersion analysis of the nucleon form factors including meson continua journal March 2007
Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized He 3 journal August 1994
Precision Rosenbluth Measurement of the Proton Elastic Form Factors journal April 2005
Precise Measurement of the Neutron Magnetic Form Factor G M n in the Few- GeV 2 Region journal May 2009
Absolute electron-proton cross sections at low momentum transfer measured with a high pressure gas target system journal January 1980
Gauge-Invariant Decomposition of Nucleon Spin journal January 1997
Analysis of electromagnetic nucleon form factors journal November 1976
The ratio of proton electromagnetic form factors via recoil polarimetry at journal January 2006
Search for Effects Beyond the Born Approximation in Polarization Transfer Observables in e p Elastic Scattering journal March 2011
Transverse Asymmetry A T from the Quasielastic 3 He ( e , e ) Process and the Neutron Magnetic Form Factor journal October 2000
Compton-Scattering Cross Section on the Proton at High Momentum Transfer journal April 2007
Nonlinear Wave-particle Interaction and Particle Trapping in Large Amplitude Dust Acoustic Waves
  • Chang, Mei-Chu; Teng, Lee-Wen; Lin, I.
  • DUSTY∕COMPLEX PLASMAS: BASIC AND INTERDISCIPLINARY RESEARCH: Sixth International Conference on the Physics of Dusty Plasmas, AIP Conference Proceedings https://doi.org/10.1063/1.3659749
conference January 2011
Measurements of electron-proton elastic cross sections for 0.4 < Q 2 < 5.5 ( GeV c ) 2 journal July 2004
Generalized Parton Distributions from Lattice QCD journal January 2004
First measurement of the electric formfactor of the neutron in the exclusive quasielastic scattering of polarized electrons from polarized 3He journal May 1994
Extraction of the neutron magnetic form factor from quasielastic 3 He ( e , e ' ) at Q 2 = 0.1 0.6 ( GeV / c ) 2 journal March 2007
Proton elastic form factor ratios to Q 2 = 3.5 GeV 2 by polarization transfer journal May 2005
Measurements of the proton elastic form factors for 1 Q 2 3 ( G e V / c ) 2 at SLAC journal June 1994
Perturbative QCD in exclusive processes journal February 1989
Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering journal November 2001
Exclusive Processes in Quantum Chromodynamics: The Form Factors of Baryons at Large Momentum Transfer journal August 1979
Semi-phenomenological fits to nucleon electromagnetic form factors journal February 1973
Dirac and Pauli form factors from lattice QCD journal October 2011
The neutron charge form factor and target analyzing powers from 3He(e→,e′n) scattering journal July 2003
Electromagnetic form factors of the peoton at low four-momentum transfer (II) journal July 1975
The applicability of perturbative QCD to exclusive processes journal May 1989
Neural network generated parametrizations of deeply virtual Compton form factors journal July 2011
Measurement of the Neutron Magnetic Form Factor journal July 1995
Measurements of the electric and magnetic form factors of the proton from Q 2 =1.75 to 8.83 (GeV/ c ) 2 journal November 1994
QCD form factors and hadron helicity nonconservation journal March 2004
Two-photon exchange in elastic electron-nucleon scattering journal September 2005
Hard exclusive reactions and the structure of hadrons journal January 2001
Backward-Angle Electron-Proton Elastic Scattering and Proton Electromagnetic Form Factors journal July 1971
Polarization transfer in elastic electron scattering from nucleons and deuterons journal January 1981
Electromagnetic form factors and the hypercentral constituent quark model journal December 2007
Basic instrumentation for Hall A at Jefferson Lab
  • Alcorn, J.; Anderson, B. D.; Aniol, K. A.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 522, Issue 3 https://doi.org/10.1016/j.nima.2003.11.415
journal April 2004
Timelike and spacelike nucleon electromagnetic form factors beyond relativistic constituent quark models journal January 2009
Flexible parametrization of generalized parton distributions from deeply virtual Compton scattering observables journal August 2011
Neutral-pion photoproduction and proton Compton scattering at large angles journal April 1979
Nucleon electromagnetic form factors from the covariant Faddeev equation journal July 2011
Effect of recent R p and R n measurements on extended Gari-Krümpelmann model fits to nucleon electromagnetic form factors journal October 2002
Charge Form Factor of the Neutron from the Reaction 2 H ( e , e n ) p journal June 1999
Proton Form Factors from Elastic Electron-Proton Scattering journal February 1966
Measurement of the Electric Form Factor of the Neutron at Q 2 = 0.5 and 1.0 G e V 2 / c 2 journal January 2004
Nucleon generalized parton distributions from full lattice QCD journal May 2008
Measurement of analyzing powers for the reaction at
  • Azhgirey, L. S.; Arefiev, V. A.; Atanasov, I.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 538, Issue 1-3 https://doi.org/10.1016/j.nima.2004.08.111
journal February 2005
Extraction of the Compton form factor H from deeply virtual Compton scattering measurements at Jefferson Lab journal May 2009
Review of two-photon exchange in electron scattering journal October 2011
Light front cloudy bag model: Nucleon electromagnetic form factors journal September 2002
Precise measurements of the neutron magnetic form factor journal June 1998
Generalized parton distributions from nucleon form factor data journal January 2005
Nucleon electromagnetic and gravitational form factors from holography journal June 2009
Measurement of G E p / G M p in e p e p to Q 2 = 5.6 GeV 2 journal February 2002
Survey of Nucleon Electromagnetic Form Factors journal March 2009
Hadron properties and Dyson–Schwinger equations journal July 2008
Measurements of the neutron electric to magnetic form factor ratio G En / G Mn via the H 2 ( e , e ' n ) H 1 reaction to Q 2 = 1.45 (GeV/ c ) 2 journal February 2006
Measurement of the Electric Form Factor of the Neutron through d ( e , e n ) p at Q 2 = 0.5 ( GeV / c ) 2 journal August 2001
G E p / G M p Ratio by Polarization Transfer in e p e p journal February 2000
Precession of the Polarization of Particles Moving in a Homogeneous Electromagnetic Field journal May 1959
SU(6) breaking effects in the nucleon elastic electromagnetic form factors journal November 2000
Nucleon form factors to next-to-leading order with light-cone sum rules journal August 2008
Q 2 independence of QF 2 / F 1 , Poincaré invariance, and the nonconservation of helicity journal June 2002
Gauge theory correlators from non-critical string theory journal May 1998
Elastic Electron-Proton Scattering at Large Four-Momentum Transfer journal July 1973
Measurement of the magnetic form factor of the neutron journal July 1993
Measurement of Elastic Electron-Neutron Cross Sections up to Q 2 = 10 ( G e V / c ) 2 journal October 1982
Nucleon electromagnetic form factors journal October 2007
Measurement of the Proton’s Electric to Magnetic Form Factor Ratio from H 1 ( e , e p ) journal January 2007
Measurement of the Neutron Electric Form Factor G en at 0.67 ( GeV / c ) 2 via 3 He ( e , e n ) journal November 1999
Measurement of the Neutron Electric Form Factor G E , n in the Quasifree H 2 ( e , e n ) p Reaction journal July 1999
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Transverse Charge Densities journal November 2010
Determination of the neutron electric form factor in the D(e,e′n)p reaction and the influence of nuclear binding journal June 1999
Reanalysis of the nucleon spacelike and timelike electromagnetic form factors in a two-component model journal June 2004
Two-photon exchange contribution to elastic electron-nucleonscattering at large momentum transfer journal July 2005
Comparison of Polarization Observables in Electron Scattering from the Proton and Deuteron journal January 1998
A fitter code for Deep Virtual Compton Scattering and Generalized Parton Distributions journal September 2008
Simple parametrization of nucleon form factors journal December 2004
Low- Q 2 measurements of the proton form factor ratio μ p G E / G M journal November 2011
Moments of nucleon generalized parton distributions from lattice QCD journal June 2011
Electromagnetic form factors in the relativistic interacting quark-diquark model of baryons journal November 2011
Charge Form Factor of the Neutron at Low Momentum Transfer from the H 2 ( e , e n ) H 1 Reaction journal July 2008
Relativistic constituent quark model of electroweak properties of baryons journal May 1993
Two-Photon Physics in Hadronic Processes journal November 2007
Precise neutron magnetic form factors journal January 2002
Proton Electromagnetic-Form-Factor Ratios at Low Q 2 journal August 2008
Deeply virtual Compton scattering at small and the access to the GPD H journal December 2010
Nucleon form factors in QCD journal May 2006
Measurement of the electric form factor of the neutron at Q2 = 0.3-0.8 (GeV/ c) 2 ⋆ journal January 2005
Exclusive processes in perturbative quantum chromodynamics journal November 1980
Covariant electroweak nucleon form factors in a chiral constituent-quark model journal May 2002
Measurements of the Proton Elastic-Form-Factor Ratio μ p G E p / G M p at Low Momentum Transfer journal November 2007
High Energy Elastic Scattering of Electrons on Protons journal August 1950
Charge Densities of the Neutron and Proton journal September 2007
Realistic transverse images of the proton charge and magnetization densities journal January 2011
Electric form factor of the neutron from the H 2 ( e →, e n ) 1 H reaction at Q 2 =0.255 (GeV/ c ) 2 journal October 1994
Measurements of the electric and magnetic form factors of the neutron from Q 2 =1.75 to 4.00 (GeV/ c ) 2 journal February 1993
General expressions for VM dominated form factors of hadrons fulfilling asymptotic conditions journal January 2003
Quarks: Currents and constituents journal February 1974
COSY INFINITY version 8 journal May 1999
Plane-wave impulse approximation extraction of the neutron magnetic form factor from quasielastic 3 He ( e , e ) at Q 2 = 0.3 to 0.6 ( GeV / c ) 2 journal January 2003
Flavor Decomposition of the Elastic Nucleon Electromagnetic Form Factors journal June 2011
Dispersion-theoretical analysis of the nucleon electromagnetic form factors: Inclusion of time-like data journal September 1996
Measurements of the Electric Form Factor of the Neutron up to Q 2 = 3.4 GeV 2 Using the Reaction 3 He ( e , e n ) p p journal December 2010
Impact Parameter Space Interpretation for Generalized Parton Distributions journal January 2003
A unitary and analytic model of nucleon EM structure, the puzzle of JLab proton polarization data and new insight into the proton charge distribution journal July 2005
Charged pion form factor between Q 2 = 0 . 60 and 2.45 GeV 2 . I. Measurements of the cross section for the 1 H ( e , e ' π + ) n reaction journal October 2008
Measurement of proton and neutron electromagnetic form factors at squared four-momentum transfers up to 3 (GeV/c)2 journal July 1973
Dyson-Schwinger equations and their application to hadronic physics journal January 1994
Measurements of exclusive photoproduction processes at large values of t and u from 4 to 7.5 GeV journal August 1976
A set of efficient estimators for polarization measurements journal December 1979
Radiative corrections for ( e , e p ) reactions at GeV energies journal October 2001
The large $N$ limit of superconformal field theories and supergravity journal January 1998
Anti de Sitter space and holography journal January 1998
Deeply virtual Compton scattering journal November 2015
Perturbative QCD in exclusive processes
  • Isgur, Nathan; Smith, C. H. Llewellyn
  • 3rd Conference on the Intersections Between Particle and Nuclear Physics, AIP Conference Proceedings https://doi.org/10.1063/1.37676
conference January 1988
Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized 3He
  • Gao, H.; Arrington, J.; Beise, E. J.
  • The 5th conference on the intersections of particle and nuclear physics, AIP Conference Proceedings https://doi.org/10.1063/1.48493
conference January 1995
Gauge-invariant decomposition of nucleon spin journal May 2011
The large N limit of superconformal field theories and supergravity conference January 1999
A fitter code for Deep Virtual Compton Scattering and Generalized Parton Distributions journal March 2009
Measurement of the Electric Form Factor of the Neutron through d-vector(e-vector, e[prime]n)p at Q2 = 0.5 (GeV/c)2 text January 2001
Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized 3He
  • Gao, H.; Arrington, J.; Beise, E. J.
  • The 14th international conference of few-body problems in physics, AIP Conference Proceedings https://doi.org/10.1063/1.48225
conference January 1995
Quarks: currents and constituents text January 1973
Nucleon Generalized Parton Distributions from Full Lattice QCD text January 2007
Hadron Properties and Dyson-Schwinger Equations text January 2007
Nucleon Form Factors to Next-to-Leading Order with Light-Cone Sum Rules text January 2008
Moments of nucleon generalized parton distributions from lattice QCD text January 2011
Review of two-photon exchange in electron scattering text January 2011
Neural network generated parametrizations of deeply virtual Compton form factors text January 2011
Dirac and Pauli form factors from lattice QCD text January 2011
Model independent radiative corrections in processes of polarized electron-nucleon elastic scattering text January 2001
Hard Exclusive Reactions and the Structure of Hadrons text January 2001
Generalized parton distributions from nucleon form factor data text January 2004
Unitary and analytic model of nucleon EM structure, the puzzle with JLab proton polarization data and new insight into proton charge distribution text January 2005
Nucleon Form Factors in QCD text January 2006
Dispersion analysis of the nucleon form factors including meson continua text January 2006
Dyson-Schwinger Equations and the Application to Hadronic Physics text January 1994
Dispersion-Theoretical Analysis of the Nucleon Electromagnetic Formfactors text January 1995
Dispersion-theoretical analysis of the nucleon electromagnetic form factors: Inclusion of time-like data text January 1996
The Large N Limit of Superconformal Field Theories and Supergravity text January 1997
Gauge Theory Correlators from Non-Critical String Theory text January 1998
Anti De Sitter Space And Holography text January 1998
$Q^2$ Independence of $QF_2/F_1$, Poincare Invariance and the Non-Conservation of Helicity text January 2002
The Role of Color Neutrality in Nuclear Physics--Modifications of Nucleonic Wave Functions text January 1995

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