SOFT PHOTON PRODUCTION IN THE BOOST-INVARIANT COLOR-FLUX TUBE MODEL

Starting from the classical expressions for emission of radiation we c alculate soft photon production in the boost-invariant color-flux tube model. In the center-of-mass system of the initial tube we find that for large energies (square-root s approximately 20 GeV) the production of photons with frequencies: 20 MeV < omega < 50 MeV, and emitted per pendicularly to the collision axis is strongly enhanced; it exceeds co nsiderably production of photons given by the Low limit. For the emiss ion more collinear with the collision axis and for decreasing omega th e effect becomes weaker and, eventually, in the limit omega = 0 we rec over precisely the Low formula. We also find that for smaller energies (square-root s approximately 5 GeV) the emission of photons is well r eproduced by the Low formula. Generally speaking, the observed enhance ment is related to the existence of a large, i.e. extended in time, re gion of photon emission. This, in turn, results from the time dilation accompanying the space-time evolution of tubes. Strong time dilation effects follow from the boost-invariance of our model and, for large s , considerably enhance radiation of soft photons. By the same token, t his enhancement decreases with decreasing s, because dilation decrease s.