ABSTRACT
We present the first direct measurements of the pion valence-quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c pi(-) into dijets from a platinum target at Fermilab experiment E791. The results show that the /q&q> light-cone asymptotic wave function describes the data well for Q2 approximately 10 (GeV/c)(2) or more. We also measured the transverse momentum distribution of the diffractive dijets.
ABSTRACT
We have studied the diffractive dissociation into dijets of 500 GeV/c pions scattering coherently from carbon and platinum targets. Extrapolating to asymptotically high energies (where t(min)-->0), we find that when the per-nucleus cross section for this process is parametrized as sigma = sigma0Aalpha, alpha has values near 1.6, the exact result depending on jet transverse momentum. These values are in agreement with those predicted by theoretical calculations of color-transparency.
ABSTRACT
We report the first observation of the Cabibbo-suppressed charm baryon decay Ξ_{c}^{+}âpK^{-}π^{+}. We observe 150±22±5 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Σ^{-} beam. The branching fractions of the decay relative to the Cabibbo-favored Ξ_{c}^{+}âΣ^{+}K^{-}π^{+} and Ξ_{c}^{+}âΞ^{-}π^{+}π^{+} are measured to be B(Ξ_{c}^{+}âpK^{-}π^{+})/B(Ξ_{c}^{+}âΣ^{+}K^{-}π^{+})=0.22±0.06±0.03 and B(Ξ_{c}^{+}âpK^{-}π^{+})/B(Ξ_{c}^{+}âΞ^{-}π^{+}π^{+})=0.20±0.04±0.02, respectively.
