Neutral pion decay in dense Skyrmion matter

Abstract

We study the density dependence of the decay π 0 → γγ using the Skyrme Lagrangian to describe simultaneously both the matter background and mesonic fluctuations. The classical ground state configuration has different chiral properties depending on the skyrmion density, which is reflected in the physical properties of pion fluctuating on top of the classical background. This leads to large suppression at high density of both photo-production from the neutral pion and the reverse process. The effective charges of π ± are also discussed in the same framework.

Neutral pion decay intoνν¯in dense Skyrmion matter

“…0 ! is not yet clear: in [17] we have observed a suppression in ÿ ! 0 while we have yet to consider the pion propagator modifications in the spirit of [10].…”

“…As in previous works [13][14][15][16][17], we describe the baryonic matter via the Skyrme model where both pions and dense baryonic matter are described by a single effective chiral Lagrangian. The basic strategy of the approach begins with the Skyrme conjecture [18] that a soliton (skyrmion) of the meson Lagrangian can be taken as a baryon so that dense baryonic matter can be approximated as a system of infinitely many skyrmions.…”

Skyrmion Approach to Finite Density and Temperature

“…[7][8][9][10][11][12][13][14] The model does not have explicit quark and gluon degrees of freedom, and therefore one can not investigate the confinement/deconfinement transition directly, but we may study the chiral symmetry restoration transition which occurs close by. The schemes which aim at approaching the phase transition from the hadronic side are labelled 'bottom up' schemes.…”

Skyrmion and Dense Matter

“…In Ref. 6) the same approach is applied to the neutral pion decay into two γ's. In the Skyrme model, the corresponding vertex to the process is obtained by gauging U em (1) fields to the Wess-Zumino-Witten term.…”