Impact ofpp→ppπ0data to negative-pion absorption on proton pairs

Abstract

Recent data on the reaction pp~ppvr close to threshold indicate unexpectedly large s-wave pion production, with a possible explanation from a heavy meson exchange contribution to the axial charge. An amplitude with the same quantum numbers appears also in negative-pion absorption on proton pairs in light nuclei. In this paper the efFect of this enhancement is estimated and found to be significant in the observables of absorption on He. Also some predictions are given for the qualitative efFect in pn M (pp)s PACS number(s): 25.80. Hp, 13.75.Cs, 13.75.Gx

Differential Cross Section of thepn→pp(1S0)Duncan1, Hahn2, Aclander3 et al. 1998Phys. Rev. Lett.Self Cite343300View full textAdd to dashboardCite

“…3 to compare with the shapes of the cross sections measured in this work. Interestingly, this calculation is similar in shape with the absorption data, but an earlier calculation (bound diproton) for the absorption data [13] is similar to the production data. Thus, the theoretical situation, at the moment, is not clear.…”

“…Conversely Hérnandez and Oset have used s-wave off-shell rescattering [16] to generate a similar explanation. The HME has been used by Niskanen [13] in a coupled-channels model (CCM) calculation of p 2 production, with his recent results shown (scaled) in Fig. 3 to compare with the shapes of the cross sections measured in this work.…”

“…It has been suggested [13] that the relatively large isospin one amplitude seen in the production data could be related to the large pp threshold p 0 production total cross sections. Both involve the same isospin one amplitude.…”

“…Also shown are the ds͞dV‫ء‬ p results (open diamonds) for 3 He͑p 2 , pn͒n scaled to compare shapes with the production cross sections. The curves are CCM calculations for production (solid) and absorption (dashed)[13] also scaled to compare shapes with the data.…”

Test of final state approximations using threshold pp→ppπ0

“…The above integrals can be calculated numerically [8]. The dominant terms near threshold are the Galilean invariance term (the second) and the rescattering terms.…”