Production of the charmed baryon Λ c + in neutron-proton interactions: BIS-2 collaboration

In this paper we study the inclusive production of the charmed baryon Λ c + in interactions of 40–70 GeV/c neutrons with protons of hydrogen target. The experiment has been performed with the use of magnetic spectrometer BIS-2 located in the neutron beam of Serpukhov accelerator. The signal of Λ c + is observed in the effective mass spectra of Λ°π+π+π−. After the removal of interactions occurring on the container of liquid hydrogen, the signal consists of 14 combinations corresponding to ≈4 standard deviations of background. Its mean value is 2262 MeV/c2, width of the bin containing signal is 20 MeV/c2. On the basis of this signal we determine the value of cross section of Λ c + production times the branching ratio of its observed decay modeσ. Br (Λ c + → Λ°π+π+π−)=0·26±0·11 μb in the kinematic region ofxF>0·5 andpT<1 GeV/c.