Measurements of the neutron-proton total cross section difference Δσ p (np) at 1.59, 1.79 and 2.20 GeVat 1.59, 1.79 and 2.20 GeV

Abstract

New results for the np spin-dependent total cross section difference AaL(np) at neutron beam kinetic energies of 1.59, 1.79 and 2.20 GeV are presented. Measurements of the AaL (rip) energy dependence were carried out at the Synchrophasotron of the Laboratory *) e-marl: sharovOsunhe.jinr.ru t) Deseased Czechoslovak Journal of Physics, Vol. 50 (2000), Suppl. S1 325 V.I.Sharov e~ al. of High Energies of the Joint Institute for Nuclear Research in Dubna. The values of AO'L were measured as a difference between the np total cross sections for parallel and antiparallel beam and target polarizations, both oriented along the beam momentum.A fast decrease of AaL(np) with increasing energy above 1.1 GeV, as it was first seen from our previous data, was confirmed. The new results are also compared with model predictions and with the phase shift analysis fits. The AO'L quantities for isosinglet state I=0, deduced from the measured values of AaL(np) and known AO'L(pp) data, are given.

Measurements of energy behaviour of spin-dependent np observables over a GeV region. Results and prospects. Dubna “DELTA—SIGMA” experiment

“…The result of the --AaL(np) measurements at 1.19, 1.59, 1.79, 2.2, 2.49, and 3.66 GeV [3][4][5][6][7] are presented in Fig. 1.…”

“…Another dynamic model prediction for the AaL(np) energy dependence was mentioned in [3][4][5][6][7]. This prediction concerns a contribution to the -AUL (rip) from the nonperturbative flavour-dependent interaction between quarks, induced by a strong fluctuation of vacuum giuon fields.…”

“…The energy dependence measurements of the np total cross section differences AaL (rip) and AaT (rip) for parallel and antiparallel particle spins, both oriented either in the longitudinal (L) or transverse (T) directions with respect to the neutron beam momentum, were proposed at the beginning of the 90-th [1,2] and started in Dubna [3][4][5][6][7]. To implement the proposed AaL,T(np) experimental program, the existing large Argonne-Saclay polarized proton target (PPT) was reconstructed in Dubna [8,9], and a new polarized neutron beam line was constructed and tested [10,11].…”

“…Two data taking runs were carried out in 1995 and 1997. The value of AaL(np) was measured at the neutron beam energies of 1.19, 1.59, 1.79, 2.20, 2.49, and 3.65 GeV [3][4][5][6][7]. The results are presented below.…”