Accelerator Neutrinos

Abstract:

We have studied two-body charmless hadronic decays of B mesons into the final states ΠΠKΠand KK. Using 3.3 × 10⁶ BB¯ pairs collected with the CLEO-II detectorwe have made the first observation of the decay B⁰ → K⁺Π^-the sum of B⁺ → Π⁺Π⁰ and B⁺ → K⁺Π⁰ decaysand see strong evidence for the decay B⁺ → K⁰Π⁺ (an average over charge-conjugate states is always implied). We place upper limits on branching fractions for the remaining decay modes. © 1998 The American Physical Society.

Abstract:

We report the first observation of B → η′X transitions with high momentum η′ mesons. We observe 39.0 ± 11.6B decay events with 2.0 < pη′ < 2.7GeV/c, the high momentum region where background from b → c processes is suppressed. We discuss the physical interpretation of the signal, including the possibility that it is due to b → sg* transitions. Given that interpretation, we find B(B → η′Xs) = [6.2 ± 1.6(stat) ± 1.3(syst)+0.0-1.5(bkg)] × 10-4 for 2.0 < pη′ < 2.7GeV/c. © 1998 The American Physical Society.

Abstract:

We have observed a signal for the decay D*⁺→D⁺γ deviations. From the measured branching ratio B(D*⁺→D⁺γ)/B(D*⁺→D⁺π⁰)=0.055±0.014±0.010 we find B(D*⁺→D⁺γ) =0.017±0.004±0.003, where the first uncertainty is statistical and the second is systematic. We also report the highest precision determination of the remaining D*⁺ branching fractions. © 1998 The American Physical Society.

Abstract:

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, (Formula presented) (Formula presented) using data collected by the CDF at Fermilab. We compare the data with predictions from a tree-level QCD calculation and the PYTHIA shower Monte Carlo program. Our data sample is particularly sensitive to contributions from initial- and final-state radiation of photons and jets. Using the PYTHIA Monte Carlo program, we contrast the kinematical distributions for direct photon production with those for initial- and final-state photon radiation (bremsstrahlung). Based on the angular distributions, we find that our data favor a mixture of bremsstrahlung and direct photon production, as predicted, over either process alone. © 1998 The American Physical Society.