Constituent Counting Rule on Various Meson-Baryon Photoproduction Reactions

The Constituent Counting Rule (CCR), inspired by quantum chromodynamics (QCD), offers an elegant approximation on the differential cross section (with respect to the Mandelstam variable “t”) of a reaction that produces two particles, with the number participating elementary fields “n". For hard scattering at large angles, the behaviour is the following dσ/dt ∽ 1/s^n-2, where “s" is the Mandelstam variable. Specifically, on meson-baryon photoproduction reactions: n-2 = 7. However, evidence suggests that this does not hold true for all reactions at all kinetmatic regimes. We present a compehensive study for various meson-baryon photoproduction reactions in an “s" range of 3-8 GeV². We investigate the evolution of the scaling for changing hard scattering conditions, such as the four-momentum transferred (-t) and the transverse momentum (p_⊥²) of the produced particles. This study offers a unique perspective of the underlined production mechanisms.