Four-Charged-Particle Final States from the Interaction of 2.7-GeV/cπ+on Deuterium

Abstract

Reactions leading to four nonstrange, charged particles from the interaction of 2.7-GeV/c w + on deuterium have been studied. Only events containing at least one visible stopping proton track were included. The spectator model of the ir + d interaction has been examined and found to be a good approximation. This model not only gives a good description of the final state of the spectator nucleon, but is also supported by the similarity of such reactions as ir + d -> ppp° and iTp -• » np°. Meson (M) resonance production in the reaction w + d->ppM is prominent, including »? (0.21 ±0.04 mb), co(0.80±0.08 mb), p(2.20zt:0.25 mb), /(0.51±0.20 mb), ,4i(0.17d=0.10 mb), ^2(0.14±0.08 mb), and 77'(0.05rfc0.02 mb) (errors are statistical). The baryon resonance A (1238) is also observed to be produced in a variety of reactions. The p and ca production processes have been examined in some detail, including a determination of the spin density matrix elements. Also, the 3w system in the ppir + r~ir° final state has been studied at energies near the A i and A 2 masses in an attempt to separate these particles from the several other processes contributing to this final state. The results of a spin-parity analysis of the A mesons are presented.

ωN final state interactions and ω-meson production from heavy-ion collisions

“…We note that using a formfactor similar to (6) for the ρN Nvertex the energy dependence of the πN →ωN production cross section as well as the differential cross sections cannot be described properly. Similar difficulties in comparing the ρexchange model with experimental data were found by other authors [24,25,26,27,28]. We, therefore, introduce a more general formfactor at the ρN N -vertex as 1…”

“…The π + n→ωp (a) and π − p→ωn (b) differential cross sections as a function of the transverse 4-momentum squared. The data were taken from Refs [24,30]. while the lines show our calculations.…”

Role of theN*(1535)resonance and theπ−p→Döring1, Oset2, Zou3 2008Phys. Rev. C282240View full textAdd to dashboardCite

“…This requires, in principle, to couple the vector mesons to all possible meson and baryon propagators and vertices provided in the rescattering series from Eq. (2). In a recent study [26], the electromagnetic form factors of the N * (1535) have been evaluated.…”

“…Actually, the π − p → φn cross section close to threshold [1] is about a factor fifty smaller than that of the π − p → ωn reaction [2,3,4]. Yet, that cross section is still less suppressed than one might expect.…”

Difference in Energy Dependence forA2−andACarroll1, Firebaugh2, Garfinkel3 et al. 1970Phys. Rev. Lett.21010View full textAdd to dashboardCite

“…1, 2 We present results from 7-BeV/c ir'p and ir + d exposures in the 30-in. Argonne National Laboratory-Midwestern Universities Research Association chamber and a 25 BeV/c u""p experiment in the 80-in.…”