Role of the pion mass in triple-Regge physics

Abstract

This paper is an extension of the investigations of Abarbanel et al., who examined asymptotic total cross sections in a multiperipheral model and obtained the surprising result that the scale for the cross sections is provided not by μ, the mass of the exchanged pion (as anticipated on geometrical grounds) but by m V, the central mass of the dominant low energy ππ resonance entering the kernel. In this paper the role of the pion mass in triple-Regge physics is clarified by examining the pion pole dominance model for the triple-Regge couplings g ijk . It is found that m V provides the scale for the inclusive link and that for this reason the couplings g ijk depend very little on the intercept α k of the exchanged reggeon. In the exclusive links if i = j = pomeron, m V once again is the only active energy scale, whereas if i = j = R, the reggeons of intercept 0.5 or less, the pion mass enters the couplings g RR k in an essential way. It is shown that the smallness of μ 2/ m V 2 is responsible for the largeness of the ratios g RR k / g PP k . These features of the model, which are in qualitative agreement with experiment, are put to a quantitative test.