Production of Δ0 resonances in p+12C collisions at 9.9 GeV/c

Abstract

The new experimental data on the inclusive reaction p+¹²C → ∆⁰ + X at an incident proton momentum of 9.9 GeV/c and various characteristics of the ∆⁰ resonances produced in p+¹²C collisions at projectile proton momentum of 4.2 and 9.9 GeV/c have been presented. The average mass and width of the mass distribution of the ∆⁰ resonances have proved to be independent of the primary energy of incident protons. The mass width of the ∆⁰ resonances produced in the target (¹²C) nucleus fragmentation region has been found to be almost half of the mass width of the ∆⁰ resonances in free hadron-nucleon collisions. The average number per one collision event of the ∆⁰ resonances produced in p+¹²C collisions at 9.9 GeV/c turned out to be about 2.4 times greater than that in p+¹²C collisions at 4.2 GeV/c. We have obtained that the hypothesis of the limiting fragmentation is not fulfilled for the ∆⁰ resonances in the inclusive reaction p+¹²C → ∆⁰ + X in the range of kinetic energy of the incident projectile protons from 3.37 to 9 GeV, corresponding to the momentum interval of incident protons from 4.2 to 9.9 GeV/c. The results of present analysis indicate that formation of the ∆⁰ resonance in the region of fragmentation of the target (¹²C) nucleus in p+¹²C collisions at 9.9 GeV/c occurs predominantly via excitation of one of the target (¹²C) neutrons to a ∆⁰ resonance, which then decays promptly into proton and π^‒ meson.