We have investigated the above processes at the CERN Intersecting Storage Rings (ISR). Results show a marked change of the slope parameter b ( t , s ) = (d/d t ) ln (d σ /d t ) around − t ≈ 0.10 GeV 2 . The s − and t − dependence of b ( t , s ) have been observed over the interval 460 GeV 2 < s < 2900 GeV 2 and 0.02 GeV 2 < t < 0.40 GeV 2 .
No description provided.
No description provided.
No description provided.
We report measured asymmetries as a function of polar scattering angle for the reactions p¯p→π−π+ and p¯p→p¯p, using a polarized proton target. The annihilation data, obtained at a p¯ momentum of 1.64 GeV/c, are the first asymmetry data to be collected for this channel. A fit of these data and published differential cross section data is made by a partial-wave expansion, and the results are compared with a previous analysis. The elastic scattering data, obtained at 1.64 and 2.55 GeV/c, are fitted with an eight-parameter strong-absorption model.
No description provided.
The analyzing power for proton-carbon elastic scattering in the coulomb-nuclear interference region of momentum transfer, $9.0\times10^{-3}<-t<4.1\times10^{-2}$ (GeV/$c)^{2}$, was measured with a 21.7 GeV/$c$ polarized proton beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory. The ratio of hadronic spin-flip to non-flip amplitude, $r_5$, was obtained from the analyzing power to be $\text{Re} r_5=0.088\pm 0.058$ and $\text{Im} r_5=-0.161\pm 0.226$.
The analyzing power as a function of the momentum transfer T. The two DSYS errors are (1) the systematic error in the raw asymmetry and (2) that in the polarization of the beam.
The recoil proton polarization of proton Compton scattering (γp→γp) was measured in the photon energy range from 500 MeV to 1000 MeV atθ∗=100° and from 400MeV to 800 MeV atθ∗=130°. A recoil proton and a scattered photon were detected in coincidence with a magnetic spectrometer and a photon detector. The recoil proton polarization was measured with a carbon polarimeter. The results are compared with a phenomenological analysis based on an isobar model and a dynamical analysis based on the dispersion relation.
No description provided.
No description provided.
The Sigma^- mean squared charge radius has been measured in the space-like Q^2 range 0.035-0.105 GeV^2/c^2 by elastic scattering of a Sigma^- beam off atomic electrons. The measurement was performed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c. We obtain
Total systematic errors are given.
We have investigated the elastic scattering of high energy $\Sigma^-$ off electrons from carbon and copper targets using the CERN hyperon beam. Scattering events a
No description provided.
Elastic scattering of linearly polarized photons on protons has been measured between 3.2 and 3.7 GeV for four-momentum transfers ranging from −0.1 to −0.7 (GeV/ c ) 2 . The observed cross section asymmetry in this range is consistent with zero within ±0.05.
No description provided.
We are reporting on a new determination of sin 2 ϑ w from the ratio of v μ e to v e scattering cross sections. A new detector designed for this purpose was exposed tothe Wide Band Neutrino Beamof the 450 GeV (CERN SPS. An analysis of data taken in 1987 and 1988 is presented based on 762 v μ e and 1017 v e events. From the ratio of σ( v μ e ) to σ( v μ e ) we determined sin 2 ϑ w =0.233±0.012 ( stat ) ± 0.008 ( syst ) without radiative correction. With radiative correction for m t = m H =100 GeV we find sin 2 ϑ w =0.232±0.012( stat )±0.008( syst ).
Data without electroweak radiative corrections.
Data corrected for electroweak radiative effects with TOP and HIGGS masses 100 GeV.
We report the results of a pion-electron scattering experiment to measure the charge radius of the pion. The experiment was performed in a 50 GeV/ c negative, unseparated beam at the IHEP accelerator, Serpukhov, and has been briefly reported in an earlier publication [1]. A magnetic spectrometer instrumented with wire spark chambers was used to record the incident pion trajectory and the angles and momenta of the scattered particles. Events are reconstructed by detailed trackfinding programs, and a set of kinematic and geometric cuts define the elastic sample. Electrons are identified both by kinematic criteria and pulse height information from total absorption lead glass Čerenkov counters. The final elastic sample consisted of 40 000 πe events in the region of four-momentum transfer squared 0.013 (GeV/ c ) 2 ⩽ q 2 ⩽ 0.036 (GeV/ c ) 2 . A full error matrix fit to the form factors of the pion gave the r.m.s. charge radius of the pion: 〈r π 2 〉 1 2 = (0.78 −0.10 +0.09 ) fm .
Axis error includes +- 0.7/0.7 contribution (DUE TO ACCIDENTAL ANTI-COINCIDENCES).
No description provided.
No description provided.
Quasielastic e-d cross sections have been measured at forward and backward angles. Rosenbluth separations were done to obtain RL and RT at Q2=1.75, 2.50, 3.25, and 4.00 (GeV/c)2. The neutron form factors GEn and GMn have been extracted using a nonrelativistic model. The sensitivity to deuteron wave function, relativistic corrections, and models of the inelastic background are reported. The results for GMn are consistent with the dipole form, while GEn is consistent with zero. Comparisons are made to theoretical models based on vector meson dominance, perturbative QCD, and QCD sum rules, as well as constituent quarks.
Magnetic form factors.
Electric form factors.
Forum