Absorption and dispersion of pions at finite temperature

We consider the pole shift in the propagator and analyse both absorptive and dispersive properties of pions at finite temperature. The leading-order term in an expansion in powers of the density is determined by the ππ forward scattering amplitude. We evaluate this amplitude in a semi-phenomenological manner, using chiral perturbation theory at threshold and relying on experimental information at higher energies. In particular we analyse the contributions generated by ρ-exchange and show that they substantially modify the lowest-order prediction of chiral perturbation theory.

pi pi: scattering amplitude
scattering amplitude: pi pi
scattering amplitude: forward scattering
forward scattering: scattering amplitude
finite temperature
pi: absorption
absorption: pi
pi: dispersion
perturbation theory: chiral
rho(770): exchange

References(16)

Figures(0)

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