English

A consistent description of rho0 -> pi pi gamma decays including sigma(500) meson effects

High Energy Physics - Phenomenology 2010-02-03 v2 High Energy Physics - Experiment

Abstract

A consistent description of σ(500)\sigma(500) meson effects in ρ0π0π0γ\rho^0\to\pi^0\pi^0\gamma and π+πγ\pi^+\pi^-\gamma decays is proposed in terms of reasonably simple amplitudes which reproduce the expected chiral-loop behaviour for large mσm_{\sigma} values. For the neutral case, in addition to the well known ω\omega exchange, there is an important contribution from the σ(500)\sigma(500) meson that is in agreement with recent experimental data. For the charged case, where the dominant contribution comes from bremsstrahlung, the effects of the σ(500)\sigma(500) meson are relevant only at high values of the photon energy and compatible with present data. A combined analysis of both processes with moderately improved experimental information should contribute decisively to clarify the status of this controversial σ(500)\sigma(500) meson.

Keywords

Cite

@article{arxiv.hep-ph/0305043,
  title  = {A consistent description of rho0 -> pi pi gamma decays including sigma(500) meson effects},
  author = {A. Bramon and R. Escribano},
  journal= {arXiv preprint arXiv:hep-ph/0305043},
  year   = {2010}
}

Comments

11 pages, 3 figures, JHEP style. A comment on the O(p^4) ChPT calculation of the four-pseudoscalar amplitudes is included; a new discussion on the effects of our parametrization on the I=J=0 pi-pi phaseshift is also included. Final version accepted for publication