Separation of S- wave pseudoscalar and pseudovector amplitudes in pi^- p---> pi^+ pi^- n reaction on polarized target
| dc.creator | Kaminski, R. | |
| dc.creator | Lesniak, L. | |
| dc.creator | Rybicki, K. | |
| dc.date | 1996-06-18 | |
| dc.date | 1997-02-11 | |
| dc.date.accessioned | 2026-07-07T10:33:19Z | |
| dc.date.available | 2026-07-07T10:33:19Z | |
| dc.description | A new analysis of S-wave production amplitudes for the reaction $π^- p_{\uparrow} \rightarrow π^+ π^- n$ on a transversely polarized target is performed. It is based on the results obtained by the CERN-Cracow -Munich collaboration in the pion-pion energy range from 600 MeV to 1600 MeV at 17.2 GeV/c $π^-$ momentum. Energy-independent separation of the S-wave pseudoscalar amplitude ($π$ exchange) from the pseudovector amplitude ($a_{1}$ exchange) is carried out using assumptions much weaker than those in all previous analyses. We show that, especially around 1000 MeV and around 1500 MeV, the $a_{1}$ exchange amplitude cannot be neglected. The scalar-isoscalar $ππ$ phase shifts are calculated using fairly weak assumptions. Below the $K\overline{K}$ threshold we find two solutions for the $π-π$ phase shifts, for which the phases increase slower with the effective $π-π$ mass than the P-wave phases. Both solutions are consistent with a broad $f_{0}(500)$ but only one is similar to the well-known "down" solution. We find also the third solution (with a somewhat puzzling behavior of inelasticity) which exhibits a narrow $f_{0}(750)$ claimed by Svec. All the solutions undergo a rapid change at the $K\overline{K}$ threshold. Above 1420 MeV the phase shifts increase with energy faster than those obtained without the polarized-target data. This phase behavior as well as an increase of the modulus of the $a_{1}$-exchange amplitude can be due to the presence of the $f_{0}(1500)$. | |
| dc.description | 25 Latex pages + 15 Postscript figures | |
| dc.identifier | https://arxiv.org/abs/hep-ph/9606362 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/9606362 | |
| dc.identifier | Z.Phys.C74:79-91,1997 | |
| dc.identifier | doi:10.1007/s002880050372 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/179069 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Separation of S- wave pseudoscalar and pseudovector amplitudes in pi^- p---> pi^+ pi^- n reaction on polarized target | |
| dc.type | text |