Speaker
Viktor Begun
(UJK)
Description
The by now well-established scalar-isoscalar resonance f0(500) (the σ meson) seems potentially relevant in evaluation of thermodynamic quantities of a hadronic gas, since its mass is low. In this talk, based on the recent work of Ref. [1], we show that its contribution to isospin-averaged observables is, to a surprising accuracy, canceled by the repulsion from the pion-pion scalar-isotensor channel. As a result, in practice one should not incorporate f0(500) in standard hadronic resonance-gas models for studies of isospin averaged quantities. In our analysis we use the formalism of the virial expansion, which allows one to calculate the thermal properties of an interacting hadron gas in terms of derivatives of the scattering phase shifts, hence in a model-independent way directly from experimentally accessible quantities. A similar cancellation mechanism occurs for the scalar kaonic interactions between I=1/2 channel (containing the alleged K∗0(800) or the κ meson) and the I=3/2 channel.
[1] W. Broniowski, F. Giacosa and V. Begun,
Why the sigma meson should not be included in thermal models,
arXiv:1506.01260 [nucl-th].
| On behalf of collaboration: | NONE |
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Authors
Prof.
Francesco Giacosa
(Kielce University)
Viktor Begun
(UJK)
Wojciech Broniowski
(IFJ PAN)
