We report results of an inclusive measurement of the charmed baryon, Λ c , in the forward direction of proton-proton interactions with s =63 GeV . The signal, seen in the final state Λ s π + π + π − , has 6.0 σ significance with about 620 events on a large background and corresponds to a cross section times branching ratio of 2.84±0.50±0.72 μ b for Feynman- x F > 0.5 in both hemispheres. Asymmetries are observed in the decay angular distributions which are characteristic of weak decays and have a combined 3.0 σ significance.
BR. RATIO WAS TAKEN TO BE 0.028+-0.007+-0.011.
Measurements are presented of two exclusive diffractive reactions, pp → (Λ 0 φ 0 K + ) p and pp → (Λ 0 Λ 0 p)p , at √ s = 63 GeV . Pronounced correlations with the beam direction are observed (in the rest frame of the forward-going bracketed system) for those outgoing particles which contain the beam valence quarks. In each case there is a forward-Λ 0 in correlation with a backward K + or p, respectively. No such behavior is seen for the particles which do not contain beam valence quarks (φ 0 and Λ 0 , respectively) . Interpreted as examples of pomeron-proton scattering, these results constitute evidence that, for these final states, the pomeron interacts with a single valence quark and apparently back-scatters it. The subsequent hadronization leads to a longitudinal event structure.
Cross sections for forward LAMBDA signal counting both arms of the p p interaction.
Cross sections for forward LAMBDA signal counting both arms of the p p interaction.
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