HEPData Search

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The transverse asymmetry A(T') from quasielastic polarized He-3(pol.)(e(pol.),e') process and the neutron magnetic form factor.

Xu, W. ; Dutta, D. ; Xiong, F. ; et al.

Phys.Rev.Lett. 85 (2000) 2900-2904, 2000.

Inspire Record 531416 DOI 10.17182/hepdata.31474

We have measured the transverse asymmetry from inclusive scattering of longitudinally polarized electrons from polarized 3He nuclei at quasi-elastic kinematics in Hall A at Jefferson Lab with high statistical and systematic precision. The neutron magnetic form factor was extracted based on Faddeev calculations with an experimental uncertainty of less than 2 %.

1 data table

Table 1

Ratio of neutron magnetic form-factor to dipole value.

Exclusive leptoproduction of rho0 mesons from hydrogen at intermediate virtual photon energies.

The HERMES collaboration Airapetian, A. ; Akopov, N. ; Akushevich, I. ; et al.

Eur.Phys.J.C 17 (2000) 389-398, 2000.

Inspire Record 526550 DOI 10.17182/hepdata.47010

Measurements of the cross section for exclusive virtual-photoproduction of rho^0 mesons from hydrogen are reported. The data were collected by the HERMES experiment using 27.5 GeV positrons incident on a hydrogen gas target in the HERA storage ring. The invariant mass W of the photon-nucleon system ranges from 4.0 to 6.0 GeV, while the negative squared four-momentum Q^2 of the virtual photon varies from 0.7 to 5.0 GeV^2. The present data together with most of the previous data at W > 4 GeV are well described by a model that infers the W-dependence of the cross section from the dependence on the Bjorken scaling variable x of the unpolarized structure function for deep-inelastic scattering. In addition, a model calculation based on Off-Forward Parton Distributions gives a fairly good account of the longitudinal component of the rho^0 production cross section for Q^2 > 2 GeV^2.

2 data tables

Table 1

Cross sections are corrected for radiative effects (which typically amount s to 18 PCT).

Table 2

Longitudinal cross sections. The listed uncertainties include both the total error on the measured RHO0 photoproduction cross sections and the error on theparametrization of R for W<7 GeV.

Delbrueck scattering at energies 140-MeV to 450-MeV.

Akhmadalev, S.Z. ; Kezerashvili, G.Ya. ; Klimenko, S.G. ; et al.

BUDKER-INP-1998-51, 1998.

Inspire Record 472470 DOI 10.17182/hepdata.50144

The differential cross section of Delbr\"{u}ck scattering is measured on a bismuth germanate $Bi_4Ge_3O_{12}$ target at photon energies $140 - 450 MeV$ and scattering angles $2.6 - 16.6 mrad$. A good agreement with the theoretical results, obtained exactly in a Coulomb field, is found.

1 data table

Table 1

Axis error includes +- 1.5/1.5 contribution (Error of measurement of the initial photons intensity).

Cross-sections and Some Features of Charm Photoproduction at $\gamma$ Energies of 20-{GeV} to 70-{GeV}

The Photon Emulsion collaboration Adamovich, M.I. ; Aleksandrov, Yu.A. ; Bolta, J.M. ; et al.

Phys.Lett.B 187 (1987) 437-441, 1987.

Inspire Record 230940 DOI 10.17182/hepdata.30199

We report some results on charm photoproduction at γ energies ranging from 20 to 70 GeV. 36 events with pairs of charmed particles have been found in emulsions. The computed total cross section is (230±57)nb/nucleon. Frequencies of different production channels and some distributions are presented and compared with the predictions from a photon-gluon fusion model with string fragmentation.

1 data table

Table 1

No description provided.