Study of hypernuclear production and search for supernuclei in proton-nuclear interactions in photoemulsion at 70 and 250 GeV

Abstract

Among 1.27·106 interactions registered in nuclear emulsion stacks exposed to 70 and 250 GeV protons 3 candidates for supernuclei (charmed nuclei) are found. The upper limits of the supernuclear yield in 70 and 250 GeV pA interactions in emulsion are 3.1·10−5 and 3.1·10−6 per inelastic interaction, respectively, at the 90% confidence level. The same quantity in interactions of ∼(100÷150) GeV leading protons is estimated to be 3.8·10−5. The upper limit of the probability of the Λc+-baryon being captured by Ag, Br nuclei at 250 GeV is estimated to be 4.0·10−3, if σ(pA→Λc+)∼A1 and 8.7·10−3, if σ(pA→Λc+)∼A2/3. 92 mesic decays of hypernuclei are analysed. The frequencies of observation of mesic decays at 70, (100÷150) and 250 GeV are determined: (3.2±1.0)·10−4, (2.7±1.2)·10−4 and (2.4±0.3)·10−4 per inelastic interaction. The hypernuclear yields at these energies are estimated to be (2.1±0.8)·10−3, (1.8±0.9)·10−3 and (1.6±0.3)·10−3, respectively.