On elastic proton-proton diffraction scattering and its energy dependence

Abstract

Recent FNAL and CERN ISR data on proton-proton elastic scattering and total cross sections at momenta q L = 200−2000 GeV/ c and momentum transfers up to | t| = 14(GeV/ c) 2 are discussed in terms of a short range expansion (SRE) of the inelastic overlap function (IOF). Model independence of the conclusions is established, which are also shown to be unaffected by real part and spin effects. The main results and conclusions are the following: (i) the SRE of the IOF is able to describe well all above data; (ii) the energy dependences of the parameters of the SRE are well reproduced by linear functions of ln sor 1/ln s as may apply; (iii) interpolating predictions of d σ/d t are made at q L = 300, 400, 500 and 1000, where experiments on the t-dependence are being done presently, as well as an extrapolating prediction at ISABELLE energy q L = 10 000; (iv) the IOF is “more diffractive” than d σ/d t and has two diffraction zeros near | t| = 0.645 and 3.83; (v) at all | t| ≳ 3.5, d σ/d t is practically equal to the square of the elastic overlap function, which overshadows the second zero of the IOF such that only the single well-known diffraction zero appears in d σ/d t; (vi) this implies that at all | t| ≳ 3.5, d σ/d t is practically built up by s-channel unitarity rescattering, and a high cross section at these t-values is hence not necessarily indicative of proton constituent effects; (vii) concavities (“breaks”) of d σ/d t as observed experimentally at | t| values 0−0.5, as well as larger than 3, are predicted features of the SRE in combination with rescattering; (viii) the ratio 5 of the forward slope of d σ/d t to the overall slope after the 2nd maximum can be understood qualitatively with the SRE.