The ratio of proton electromagnetic form factors via recoil polarimetry at

MacLachlan, G. A.; Aghalaryan, A.; Ahmidouch, A.; Anderson, B. D.; Asaturyan, R.; Baker, O. K.; Baldwin, A. R.; Barkhuff, D.; Breuer, H.; Carlini, R.; Christy, E.; Churchwell, S.; Cole, Leon J.; Crouse, E.; Danagoulian, S.; Day, D.; Eden, T.; Elaasar, M.; Ent, R.; Farkhondeh, M.; Fenker, H.; Finn, J. M.; Gan, Lu; Garrow, K.; Guèye, P.; Howell, C. R.; Hu, Bingcheng; Jones, M.; Kelly, James; Keppel, C.; Khandaker, M.; Kim, W.-Y.; Kowalski, S.; Lai, A.; Lung, A.; Mack, D.; Madey, R.; Manley, D. M.; Markowitz, P.; Mitchell, J.; Mkrtchyan, H.; Opper, A. K.; Plaster, B.; Perdrisat, C. F.; Punjabi, V.; Raue, B. A.; Reichelt, T.; Reinhold, J.; Roche, J.; Sato, Y.; Savvinov, N.; Semenov, A. Yu.; Семенова, И. А.; W, Seo; Šimičević, N.; Smith, G. R.; Taylor, S.; Stepanyan, S.; Tadevosyan, V.; Tajima, S.; Tang, L.; Tireman, W.; Ulmer, P.; Vulcan, W.; Watson, J. W.; Wells, S. P.; Wesselmann, F. R.; Wood, S. A.; C, Yan; Yan, Chenyu; Yang, Sung-Chul; Yuan, L.; Zhang, W.-M.; Zhu, Haibin; Zhu, Xiwen

doi:10.1016/j.nuclphysa.2005.09.012

Cited by 51 publications

(27 citation statements)

References 17 publications

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“…For the proton, we fit directly to unpolarized cross section data [17,36, and to G p E /G p M ratios extracted from polarization data [76][77][78][79][80][81][82][83][84][85][86][87][88]. Note that the data taken from Refs.…”

Section: Proton Datamentioning

confidence: 99%

Proton and neutron electromagnetic form factors and uncertainties

et al. 2018

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Section: Proton Datamentioning

confidence: 99%

Proton and neutron electromagnetic form factors and uncertainties

et al. 2018

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“…Polarization transfer from a polarized electron to a proton in an elastic scattering reaction has become a recognized method to measure the ratio of the proton's elastic electromagnetic form factors G E /G M [1][2][3][4][5][6][7][8][9]. For a proton initially at rest, assuming the one-photon exchange approximation, the ratio of the transverse (P x ) to longitudinal (P z ) polarization-transfer components, with respect to the momentum transfer q, is proportional to G E /G M [10]:…”

Section: Introductionmentioning

confidence: 99%

The influence of Fermi motion on the comparison of the polarization transfer to a proton in elastic e→p and quasi-elastic e
Paul
¹
,
Brecelj
²
,
Arenhövel
³

et al. 2019
Physics Letters B
6
1
17
0
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A comparison between polarization-transfer to a bound proton in quasi-free kinematics by the A( e, e p) knockout reaction and that in elastic scattering off a free proton can provide information on the characteristics of the bound proton. In the past the reported measurements have been compared to those of a free proton with zero initial momentum. We introduce, for the first time, expressions for the polarization-transfer components when the proton is initially in motion and compare them to the 2 H data measured at the Mainz Microtron (MAMI). We show the ratios of the transverse (P x ) and longitudinal (P z ) components of the polarization transfer in 2 H( e, e p)n, to those of elastic scattering off a "moving proton", assuming the proton's initial (Fermi-motion) momentum equals the negative missing momentum in the measured reaction. We found that the correction due to the proton motion is up to 20% at high missing momentum. However the effect on the double ratio (Px/Pz) A (Px/Pz) 1 H is largely canceled out, as shown for both 2 H and 12 C data. This implies that the difference between the restingand the moving-proton kinematics is not the primary cause for the deviations between quasi-elastic and elastic scattering reported previously.

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“…Figure 1-6 shows a representative sample of data obtained from both cross section and polarization experiments on the proton form factor ratio [19,28,20,22,25] aration experiments. Experiments [31,33,35,36,37] used recoil polarization, while [30,34] used polarized targets and measured the beam-target asymmetry (1.96). The polarization transfer experiments at high Q 2 [33,31] revealed with high precision a strong deviation from the empirical scaling law µ p G p E /G p M = 1 and from all existing Rosenbluth separation data at similar Q 2 .…”

Section: Existing Nucleon Form Factor Datamentioning

confidence: 99%

Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to High Momentum Transfer

Puckett

2010

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The electromagnetic form factors of the nucleon characterize the effect of its internal structure on its response to an electromagnetic probe as studied in elastic electronnucleon scattering. These form factors are functions of the squared four-momentum transfer Q 2 between the electron and the proton. The two main classes of observables of this reaction are the scattering cross section and polarization asymmetries, both of which are sensitive to the form factors in different ways. When considering large momentum transfers, double-polarization observables offer superior sensitivity to the electric form factor. This thesis reports the results of a new measurement of the ratio of the electric and magnetic form factors of the proton at high momentum transfer using the recoil polarization technique. A polarized electron beam was scattered from a liquid hydrogen target, transferring polarization to the recoiling protons. These protons were detected in a magnetic spectrometer which was used to reconstruct their kinematics, including their scattering angles and momenta, and the position of the interaction vertex. A proton polarimeter measured the polarization of the recoiling protons by measuring the azimuthal asymmetry in the angular distribution of protons scattered in CH 2 analyzers. The scattered electron was detected in a largeacceptance electromagnetic calorimeter in order to suppress inelastic backgrounds. The measured ratio of the transverse and longitudinal polarization components of the scattered proton is directly proportional to the ratio of form factors G AcknowledgmentsThis thesis would not have been possible without the support and efforts of many, many people. It would be impossible to give all due credit to all of the individual efforts that went into designing, planning, staging, and executing this experiment, and the subsequent analysis of the data. Therefore, any omissions from the following acknowledgments are in no way meant to diminish those contributions.I would like to thank the members of the GEp-III collaboration whose tireless efforts made experiments E04-108 and E04-019 a success. This includes the spokespeople; Ed Brash, Mark Jones, Charles Perdrisat and Vina Punjabi, and the other outstanding physicists involved in the core collaboration. I thank Frank Wesselmann for his successful leadership of the testing, installation, commissioning and operation of the Focal Plane Polarimeter, and his significant contribution to the data analysis in the form of the event decoding and tracking software for the FPP drift chambers. I thank Mark Jones for his encyclopedic knowledge of experimental Hall C and for his outsized contribution to making the various parts of the experiment work together as a whole, and for being called upon more often than not to troubleshoot problems with the experiment as they occurred. Mark's many important contributions to the data analysis included the optimization of the HMS reconstruction coefficients. Much of what I have learned about the actual hands-on require...

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The ratio of proton electromagnetic form factors via recoil polarimetry at

Cited by 51 publications

References 17 publications

Proton and neutron electromagnetic form factors and uncertainties

Proton and neutron electromagnetic form factors and uncertainties

The influence of Fermi motion on the comparison of the polarization transfer to a proton in elastic e→p and quasi-elastic e
Paul
¹
,
Brecelj
²
,
Arenhövel
³

et al. 2019
Physics Letters B
6
1
17
0
View full text Add to dashboard Cite

Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to High Momentum Transfer

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The ratio of proton electromagnetic form factors via recoil polarimetry at

Cited by 51 publications

References 17 publications

Proton and neutron electromagnetic form factors and uncertainties

Proton and neutron electromagnetic form factors and uncertainties

The influence of Fermi motion on the comparison of the polarization transfer to a proton in elastic e→p and quasi-elastic ePaul1, Brecelj2, Arenhövel3 et al. 2019Physics Letters B61170View full textAdd to dashboardCite

Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to High Momentum Transfer

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The influence of Fermi motion on the comparison of the polarization transfer to a proton in elastic e→p and quasi-elastic e
Paul
¹
,
Brecelj
²
,
Arenhövel
³

et al. 2019
Physics Letters B
6
1
17
0
View full text Add to dashboard Cite