21145414
Search for exclusive charmless hadronic B decays.
We have searched for two-body charmless hadronic decays of B mesons. Final states include ππ, Kπ, and KK with both charged and neutral kaons and pions: πρ, Kρ, and K^*π; and Kφ, K^*φ, and φφ. The data used in this analysis consist of 2.6×10^6 BB¯ pairs produced at the Υ(4S) taken with the CLEO II detector at the Cornell Electron Storage Ring (CESR). We measure the branching fraction of the sum of B^0→π^+π^- and B^0→K^+π^- to be (1.8_(-0.5-0.3)^(+0.6+0.2)±0.2)×10^(-5). In addition, we place upper limts on individual branching fractions in the range from 10^(-4) to 10^(-6).
53322828
Evidence of electron neutrino appearance in a muon neutrino beam
The T2K collaboration reports evidence for electron neutrino appearance at the atmospheric mass splitting, |\Delta m_{32}^2|=2.4x10^{-3} eV^2. An excess of electron neutrino interactions over background is observed from a muon neutrino beam with a peak energy of 0.6 GeV at the Super-Kamiokande (SK) detector 295 km from the beam's origin. Signal and background predictions are constrained by data from near detectors located 280 m from the neutrino production target. We observe 11 electron neutrino candidate events at the SK detector when a background of 3.3\pm0.4(syst.) events is expected. The background-only hypothesis is rejected with a p-value of 0.0009 (3.1\sigma), and a fit assuming \nu_{\mu}->\nu_e oscillations with sin^2(2\theta_{23})=1, \delta_{CP}=0 and |\Delta m_{32}^2|=2.4x10^{-3} eV^2 yields sin^2(2\theta_{13})=0.088^{+0.049}_{-0.039}(stat.+syst.).
17470539
The KamLAND full-volume calibration system
We have successfully built and operated a source deployment system for the KamLAND detector. This system was used to position radioactive sources throughout the delicate 1-kton liquid scintillator volume, while meeting stringent material cleanliness, material compatibility, and safety requirements. The calibration data obtained with this device were used to fully characterize detector position and energy reconstruction biases. As a result, the uncertainty in the size of the detector fiducial volume was reduced by a factor of two. Prior to calibration with this system, the fiducial volume was the largest source of systematic uncertainty in measuring the number of antineutrinos detected by KamLAND. This paper describes the design, operation and performance of this unique calibration system.
118399478
Study of two-body B decays to kaons and pions: Observation of B ---> pi+ pi-, B ---> K+- pi0, and B ---> K0 pi0 decays
17545140
First observation of the sigma(*+)(c) baryon and a new measurement of the sigma(*+)(c) mass.
Using data recorded with the CLEO II and CLEO II.V detector configurations at the Cornell Electron Storage Rings, we report the first observation and mass measurement of the Sigma(*+)(c) charmed baryon, and an updated measurement of the mass of the Sigma(+)(c) baryon. We find M(Sigma(*+)(c))-M(Lambda(+)(c)) = (231.0+/-1.1+/-2.0) MeV, and M(Sigma(+)(c))-M(Lambda(+)(c)) = (166.4+/-0.2+/-0.3) MeV, where the errors are statistical and systematic, respectively.
125105616
Determination of the B ---> D* l nu decay width and |V(cb)|
38420080
Limits on the lifetime of the shape isomer of 238U.
1396364
Analytic calculation of prompt photon plus associated heavy flavor at next-to-leading order in QCD.
Contributions through second order, {ital O}({alpha}{sup 2}{sub {ital s}}), in perturbative quantum chromodynamics are calculated analytically for inclusive associated production of a prompt photon and a charm quark at large values of transverse momentum in high energy hadron-hadron collisions. Seven partonic subprocesses contribute at order {alpha}{sup 2}{sub {ital s}}. We find important corrections to the lowest order, {ital O}({alpha}{sub {ital s}}), subprocess {ital cg}{r_arrow}{gamma}{ital c}. We demonstrate to what extent data from {ital p}+{bar {ital p}}{r_arrow}{gamma}+{ital c}+{ital X} may serve to measure the charm quark density in the nucleon. {copyright} {ital 1996 The American Physical Society.}
41410937
Prospects for supersymmetry at the Fermilab collider.
We compute cross sections for production of pairs of strongly interacting supersymmetric (SUSY) particles in p-italicp-bar collisions as a function of collider energy. For a scalar-quark or gluino mass of 80 GeV, we find that the ratio of the SUSY cross section to the standard-model background increases by a factor of about 10 when ..sqrt..s-italic is increased from 630 to 1600 GeV. If decays to photinos are dominant, we show that in the first 2 years of running, experiments at the Fermilab Tevatron collider should be sensitive to gluino (scalar-quark) masses up to at least m-italic/sub g-italic-tilde/ = 150 GeV (m-italic/sub q-italic-tilde/ = 120 GeV). We show characteristic missing-p-italic/sub T-italic/ distributions expected if SUSY particles with such masses are produced. For SUSY particles of large mass, we stress the importance of scalar-quark and gluino decays to W-italic and Z-italic gauginos.
27651738
Classification and JPG selection rules for weak currents.
Four categories are defined of exotic and nonexotic first-class and second-class weak currents, three of which are suppressed in the standard model. Hadronic final states produced through various symmetry-breaking mechanisms are subject to selection rules which govern their allowed values of J/sup P//sup G/. We show that there are four types of suppressed transitions and give examples of each.
45214989
Probing gluon polarization in hadronic direct photon production.
Inclusive direct photon production at large transverse momentum in proton-proton interactions with a longitudinally polarized beam and target is an incisive probe of the polarized gluon density in a proton. To help motivate future experiments and assist in their design, we provide predictions of the polarization asymmetry for a range of reasonable choices of the polarized gluon density. The cross sections are small at fixed-target energies, but the effort to measure them is necessary if the polarized gluon density /Delta//ital G/(/ital x/,/ital Q//sup 2/) is to be determined. In order to obtain our predictions, we parametrize spin-dependent parton densities and compute their evolution with /ital Q//sup 2/. Our densities provide good agreement with the spin-dependent structure function /ital g//sub 1//sup /ital p//(x,/ital Q//sup 2/) measured in deep-inelastic lepton scattering.