Search results for "Virtual particle"

Measurements of $R^{d}-R^{p}$ and $R^{Ca}-R^{C}$ in deep inelastic muon scattering

1992

Results are presented on the difference in R, the ratio of longitudinally to transversely polarised virtual photon absorption cross sections, for the deuteron and the proton. They are obtained by c ...

Medium energy physics with c.w. electron accelerators

2008

Measurement of the proton and deuteron structure functions, F2p and F2d, and of the ratio

1997

The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002 < x < 0.60 and 0.5 < Q(2) < 75 GeV2 at incident muon energies of 90, 120, 200 and 280 GeV. These results are based on the full data set collected by the New Muon Collaboration, including the data taken with a small angle trigger. The extracted values of the structure functions F-2(p) and F-2(d) are in good agreement with those from other experiments. The data cover a sufficient range of y to allow the determination of the ratio of the longitudinally to transversely polarised virtual photon absorption cross sections, R = sigma(L)/sigma(T), for 0.002 < x < 0.12. The …

The pion electroproduction and the virtual-photon theory

1983

The double differential cross-section for pion electroproduction was measured for the processes p(e,π+n and12C(e,π+)12B. The proton-induced cross-section was evaluated by using the virtual-photon concept. The experimental data were used to test different formulae for the virtual-photon spectrum. We found significant deviations to a generally used formula (Dalitz-Yennie) and good agreement with a new formula (Tiator-Wright). In addition, we have measured pion production crosssections with real photons under equal kinematic conditions. Electro-and photoproduction measurements give the same results.

Virtual Compton Scattering at MAMI γ*p→ γ1p1

1999

The virtual Compton scattering (VCS) is the electron scattering on a proton which radiates a real photon before being detected. The new observables, called Generalized Polarizabilities (GP), extracted from this VCS at threshold can be understood as the deformation of the charge and current distributions of the proton [1]. These GP are functions of the mass of the virtual photon Q2. In real Compton scattering (Q2 = 0), some polarizabilities of the nucleon are already measured [2]. With the VCS, we will generalize these observables by measuring them at different values of Q2.

The Experimental Program of the MAMI-Project

1992

At Mainz university, a 100% duty-factor electron accelerator for beam current and energy up to 100 µA and 855 MeV,respectively, has become operational recently, the Mainz Microtron MAMI. The experimental program is based on three major equipments which are built up and will be run by three facility-oriented collaborations. Collaboration A1 is centered around a magnetic spectrometer setup and will do experiments with virtual photons. For experiments with real photons collaboration A2 runs a high-efficiency tagger. Collaboration A3 sets up a polarized electron source in order to exploit the polarization degrees of freedom.

A time-of-flight facility for the measurement of electron-induced neutron spectra

1974

Abstract A time-of-flight facility is constructed to investigate photoneutrons in the energy range 5 MeV ≤ En ≤ 200 MeV. Photoneutrons are detected simultaneously at four angles (40.2°, 90°, 113.5°, 142.2°). The overall time resolution varies from 0.282 ns/m to 0.358 ns/m, depending on the different flight paths (18.56 m to 11.40 m). As a first check the facility is used to measure the ratio of the number of virtual photons to real photons via the photodisintegration of 2H. The measured values agree with the calculated photon spectra.

Exact PWBA virtual photon spectrum for a(γv, D)R

1984

Virtual compton scattering under π0 threshold at Q2=0.33 GeV2. Preliminary results

1999

We have measured the absolute unpolarized cross sections for photon electro-production off the proton ep → epγ with the Three-Spectrometer-Setup at MAMI at a momentum transfer q=600 MeV/c and a virtual photon polarization ɛ=0.62. The momentum q ′ of the outgoing real photon range from 33 to 111 MeV/c. We extracted two combinations of the recently introduced generalized polarizabilities [1,2].

Electro- and photodisintegration of deuterium

1978

Deuteron break-up by inelastic electron scattering or photoabsorption is discussed with emphasis on effects from meson exchange currents and isobar configurationgurations.