HEPData Search

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Measurement of the neutral weak form factors of the proton.

The HAPPEX collaboration Aniol, K.A. ; Armstrong, D.S. ; Baylac, M. ; et al.

Phys.Rev.Lett. 82 (1999) 1096-1100, 1999.

Inspire Record 478059 DOI 10.17182/hepdata.31319

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The kinematic point (theta_lab = 12.3 degrees and Q^2=0.48 (GeV/c)^2) is chosen to provide sensitivity, at a level that is of theoretical interest, to the strange electric form factor G_E^s. The result, A=-14.5 +- 2.2 ppm, is consistent with the electroweak Standard Model and no additional contributions from strange quarks. In particular, the measurement implies G_E^s + 0.39G_M^s = 0.023 +- 0.034 (stat) +- 0.022 (syst) +- 0.026 (delta G_E^n), where the last uncertainty arises from the estimated uncertainty in the neutron electric form factor.

1 data table

Table 1

Longitudinally polarized beam. C=L and C=R means left- and right polarization. The second systematic uncertainty arises from the estimated uncertainty inthe neutron electromagnetic from factor.

Parity violation in elastic electron proton scattering and the proton's strange magnetic form-factor.

The SAMPLE collaboration Spayde, D.T. ; Averett, T. ; Barkhuff, D. ; et al.

Phys.Rev.Lett. 84 (2000) 1106-1109, 2000.

Inspire Record 507265 DOI 10.17182/hepdata.31230

We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A=-4.92 +- 0.61 +- 0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.

1 data table

Table 1

Polarized beam. FORMFACTOR(NAME=GM_S) is the strange quark contribution. FORMFACTOR(NAME=GM_S) is in nucleon magnetic FF.

Measurement of the proton's neutral weak magnetic form factor.

The SAMPLE collaboration Mueller, B. ; Beck, D.H. ; Beise, E.J. ; et al.

Phys.Rev.Lett. 78 (1997) 3824-3827, 1997.

Inspire Record 440739 DOI 10.17182/hepdata.31349

We report the first measurement of the parity-violating asymmetry in elastic electron scattering from the proton. The asymmetry depends on the neutral weak magnetic form factor of the proton which contains new information on the contribution of strange quark-antiquark pairs to the magnetic moment of the proton. We obtain the value $G_M~Z= 0.34 \pm 0.09 \pm 0.04 \pm 0.05$ n.m. at $Q~2=0.1$ (GeV/c)${}~2$.

1 data table

Table 1

Polarized beam. FORMFACTOR(NAME=GZM) = (1/4)*(GM_P-GM_N) - SIN2TW*GM_P - (1/4)*GM_S, whereFORMFACTOR(NAME=GM_S) is the strange quark contribution. FORMFACTOR(NAME=GZM) and FORMFACTOR(NAME=GM_S) are in nucleon magnetic FF.

Measurement of the vector analyzing power in elastic electron proton scattering as a probe of double photon exchange amplitudes.

The SAMPLE collaboration Wells, S.P. ; Averett, T. ; Barkhuff, D. ; et al.

Phys.Rev.C 63 (2001) 064001, 2001.

Inspire Record 524209 DOI 10.17182/hepdata.31444

We report the first measurement of the vector analyzing power in inclusive transversely polarized elastic electron-proton scattering at Q^2 = 0.1 (GeV/c)^2 and large scattering angles. This quantity should vanish in the single virtual photon exchange, plane wave impulse approximation for this reaction, and can therefore provide information on double photon exchange amplitudes for electromagnetic interactions with hadronic systems. We find a non-zero value of A=-15.4+/-5.4 ppm. No calculations of this observable for nuclei other than spin 0 have been carried out in these kinematics, and the calculation using the spin orbit interaction from a charged point nucleus of spin 0 cannot describe these data.

1 data table

Table 1

Polarized beam.

Backward electron-deuteron scattering below 280 mev

Ganichot, D. ; Grossetete, B. ; Isabelle, D.B. ;

Nucl.Phys.A 178 (1972) 545-562, 1972.

Inspire Record 75366 DOI 10.17182/hepdata.8775

We measured the elastic and inelastic scattering of electrons on deuterium at 180° for four incident energies (70, 140, 210 and 280 MeV). The data were analysed with a technique allowing an accurate comparison between experiment and theory. We observed a good agreement for the inelastic data with the expected cross section, using the presently available models and nucleon form factors. The experimental elastic cross section is systematically larger than the predicted cross sections.

16 data tables

Table 1

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Electrodisintegration of the Deuteron Around q2=3.5 F-2

Grossetete, B. ; Jullian, S. ; Lehmann, P. ;

Phys.Rev. 141 (1966) 1435-1440, 1966.

Inspire Record 944958 DOI 10.17182/hepdata.462

We have measured the absolute cross sections of the electron-deuteron scattering at q2=3.5 F−2 and obtained the complete inelastic spectrum. Three points for each spectrum are given with a 4% accuracy. The scattering angles, 60° and 130°, were chosen to allow the separation between electric and magnetic scattering. Calculations of radiative corrections were made in order to permit the comparison of the spectra with the inelastic-scattering theories.

20 data tables

Table 1

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The Charge Form Factor of the Proton at a Momentum Transfer of 75 F$^-^2$

Bartel, W. ; Dudelzak, B. ; Krehbiel, H. ; et al.

Phys.Lett.B 25 (1967) 236-237, 1967.

Inspire Record 1333753 DOI 10.17182/hepdata.29448

The proton form factors GE(q2) and GM(q2) are determined at q2 = 75fm−2.

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Scattering of positrons and electrons from protons

Bartel, W. ; Dudelzak, B. ; Krehbiel, H. ; et al.

Phys.Lett.B 25 (1967) 242-245, 1967.

Inspire Record 1389651 DOI 10.17182/hepdata.29449

The ration R = σ(e + = p)/σ(e − + p) of the elastic scattering cross section of positrons and electrons on protons was measured at momentum transfers of 11.66 fm −2 and 35.1 fm −2 . The results are consistent with R = 1.

1 data table

Table 1

No description provided.