The neutrino energy loss rate is calculated due to the photoneutrino process in a hot plasma, under magnetic field.The calculations done for Iow densities and re]atively ]ow temperatures may be used for astrophysical estimations in neutron stars.
IntroduetionRecent progress in the production of a strong magnetic field in the laboratory [1] has focussed interest on the study of the effect of magnetic fields on various phenomena [2]. The largest field t h a t can now be produced in the laboratory is of the order of 1 5 G, which is much smaHer than that existing in neutron stars, which ma)" be of the order of 10 ~ G [3].Canonical models for the description of the weak interaction among fermions predicts a direct interaction between electron-neut¡ pairs [4]. The effective Hamiltonian which describes the eleetron neutrino interactions is H,,---ig (~~ ~,~(1 -5 Zs)V',,)(W,, 9'~ (1 --5 y.~)%).(1) 8m',,, Such an interaction follows immediately in conventional theories in which the weak interaction is mediated by a few intermediate vector bosons [5], or when the weak coupling has the forro phenomenologically at least of current-current interaction.A Fierz transformation of the Hamiltonian of Eq. (1) yields the equivalent form Hw = _ i/___~2 [~e Y,, V'e)(~,, }'. (1 + Ys) %) + (~, Y6 Y,, 'P,)(~,, ~'. (1 + Ys) V',,)], 8 m~ (2)which exhibits more explicitly the matrix element for a neut¡241 pair to be radiated by ah electron, by means of a vector or axial rector current. The vector current is analogous to the coupling of an eleetron to a photon and Acla Physica Aeod+miae Sci+n+iar~m lt.ngori+o+ 39, 1975
