Study of the strong coupling constants, α_s (q² ) of π- and K⁰ mesons from π^-+p and π^-+C interactions at 40 GeV/c

Abstract

This paper is devoted to the production of π^-and K⁰ mesons from π^-+p→π^-+X and π^-+C→π^-,K⁰+X interactions at 40 GeV/c as a function of the square of four momentum transfer. The cut parameter of the strong coupling constant is taken as Λ_ac²=m_a²+m_c². Values of the strong coupling constant are then compared to leading-order and next-to-leading-order perturbative QCD calculations for the first time. Agreement between the experimental data and theory is good, thus providing a precision test of QCD at large momentum transfers (q). The strong coupling constant α_s is extracted as a function of q, showing a good agreement with the renormalisation group equation and with previous analyses. As the momentum transfers increases, the running coupling constant decreases. For each high-energy interaction, a quantity called the cut parameter is chosen differently depending on the secondary particles produced by the reaction. For each high-energy interaction, a quantity called the cut parameter is chosen differently depending on the secondary particles produced by the reaction.