Angular distributions of light projectile fragments in deep inelastic Pb + Em interactions at 160 A GeV

Abstract.

The nuclear emulsion was exposed at CERN by the lead projectile at 160 A GeV. The angles between any pair of fragments with Z= 2–4 have been measured in the emulsion plane for the events which did not contain heavy fragments. The constant characterizing the normal angle (φ) distribution of the fragment momentum projection onto the emulsion plane with respect to initial projectile momentum p ₀ is found to be σ_φ= (0.37 ± 0.02) mrad. Corresponding value σ₀= (121 ± 6) MeV/c of nucleon momentum distribution in the lead nucleus coincides with that expected from Fermi momentum distribution for this nucleus. The peak in the pair-angle distribution of double-charged fragments, ⁸Be → 2α, is presented for the region of small angles (<0.1 mrad). The fraction of α-particles coming from the decay of the ground state ⁸Be is found to be (13 ± 2)% of their whole number.