A study on analytic parametrizations for proton-proton cross-sections and asymptotia

Author(s)

Menon, M. J. ^[1] ; Silva, P. V. R. G. ^[1]

Affiliation

^[1] Univ Estadual Campinas UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS; v. 40, n. 12 DEC 2013.
• Web of Science Citations: 15

Abstract

A comparative study on some representative parametrizations for the total and elastic cross-sections as a function of energy is presented. The dataset comprises pp and (p) over barp scattering in the c.m. energy interval 5 GeV-8 TeV. The parametrization for the total cross-section at low and intermediate energies follows the usual reggeonic structure (non-degenerate trajectories). For the leading high-energy pomeron contribution, we consider three distinct analytic parametrizations: either a power (P) law, or a log-squared (L2) law or a log-raised- to-gamma (L gamma) law, where the exponent gamma is treated as a real free fit parameter. The parametrizations are also extended to fit the elastic (integrated) cross-section data in the same energy interval. Our main conclusions are the following: (1) the data reductions with the logarithmic laws show strong dependence on the unknown energy scale involved, which is treated here either as a free parameter or fixed at the energy threshold; (2) the fit results with the P law, the L2 law (free scale) and the L gamma law (fixed scale and exponent gamma above 2) are all consistent within their uncertainties and with the experimental data up to 7 TeV, but they partially underestimate the high-precision TOTEM measurement at 8 TeV; (3) once compared with these results, the L2 law with fixed scale is less consistent with the data and, in the case of a free scale, this pomeron contribution decreases as the energy increases below the scale factor (which lies above the energy cutoff); (4) in all cases investigated, the predictions for the asymptotic ratio between the elastic and total cross-sections, within the uncertainties, do not exceed the value 0.430 (therefore, below the black-disc limit) and the results favor rational limits between 1/3 and 2/5. We are led to conclude that the rise of the hadronic cross-sections at the highest energies still constitutes an open problem, demanding further and detailed investigation. (AU)

• FAPESP's process: 11/15016-4 - A Phenomenological Analysis on the Proton-Proton Elastic Scattering at the LHC Energy Region
• Grantee: Paulo Victor Recchia Gomes da Silva
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 09/50180-0 - Study of hadronic interactions at high energies
• Grantee: Yogiro Hama
• Support Opportunities: Research Projects - Thematic Grants