Measurement of σΛB0/σ0 x B(Λb0→Λc+π-)/B(B)over-bar0→D+π-) in p(p)over-bar collisions at √s=1.96 TeV

We present the first observation of the baryon decay Lambda(0)(b)->Lambda(+)(c)pi(-) followed by Lambda(+)(c)-> pK(-)pi(+) in 106 pb(-1) p (p) over bar collisions at root s=1.96 TeV in the CDF experiment. In order to reduce systematic error, the measured rate for Lambda(0)(b) decay is normalized to the kinematically similar meson decay (B) over bar (0)-> D+pi(-) followed by D+->pi K-+(-)pi(+). We report the ratio of production cross sections (sigma) times the ratio of branching fractions (B) for the momentum region integrated above p(T)> 6 GeV/c and pseudorapidity range |eta|< 1.3: sigma(p (p) over bar ->Lambda X-0(b))/sigma(p (p) over bar ->(B) over bar X-0)xB(Lambda(0)(b)->Lambda(+)(c)pi(-))/B((B) over bar (0)-> D+pi(-))=0.82 +/- 0.08(stat)+/- 0.11(syst)+/- 0.22[B(Lambda(+)(c)-> pK(-)pi(+))].