32525273
Search for CP violation in D0 decay.
R. Balest, K. Cho, W.T. Ford, M. Lohner, H. Park, P. Rankin, and J.G. Smith University of Colorado, Boulder, Colorado 80809 0890J.P. Alexander, C. Bebek, B.E. Berger, K. Berkelman, K. Bloom, T.E. Browder, * D.G. Cassel, H.A. Cho, D.M. Coffman, D.S. Crowcroft, M. Dickson, P.S. Drell, D.J. Dumas, R. Ehrlich, R. Elia, P. Gaidarev, M. Garcia-Sciveres, B. Gittelman, S.W. Gray, D.L. Hartill, B.K. Heltsley, S. Henderson, C.D. Jones, S.L. Jones, J. Kandaswamy, N. Katayama, P.C. Kim, D.L. Kreinick, T. Lee, Y. Liu, G.S. Ludwig, J. Masui, J. Mevissen, N.B. Mistry, C.R. Ng, E. Nordberg, J.R. Patterson, D. Peterson, D. Riley, and A. So8'er Cornell University, Ithaca, New York 1/858
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).
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.
118399478
Study of two-body B decays to kaons and pions: Observation of B ---> pi+ pi-, B ---> K+- pi0, and B ---> K0 pi0 decays
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.
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.).
6451793
Mean-field description of ground-state properties of drip-line nuclei: Pairing and continuum effects.
Ground-state properties of exotic even-even nuclei with extreme neutron-to-proton ratios are described in the framework of self-consistent mean-field theory with pairing formulated in coordinate space. This theory properly accounts for the influence of the particle continuum, which is particularly important for weakly bound systems. The pairing properties of nuclei far from stability are studied with several interactions emphasizing different aspects, such as the range and density dependence of the effective interaction. Measurable consequences of spatially extended pairing fields are presented, and the sensitivity of the theoretical predictions to model details is discussed. {copyright} {ital 1996 The American Physical Society.}
10820318
Implications of bottom-quark cross section data at hadron collider energies.
In next-to-leading-order {ital O}({alpha}{sub {ital s}}{sup 3}) quantum chromodynamics, gluon-gluon interactions are the dominant mechanism for the production of bottom quarks at CERN and Fermilab hadron collider energies at values of momentum transfer currently accessible. There is a notable discrepancy between the data from the Collider Detector at Fermilab and existing {ital O}({alpha}{sub {ital s}}{sup 3}) theoretical calculations. Using these data, in conjunction with data from deep-inelastic lepton scattering, we show that it is possible to determine a new gluon density whose shape differs substantially from that derived from previous fits to data. Other implications of the data are discussed.
42847515
Bottom-quark production at hadron colliders.
The recent measurement by the UA1 group of the cross section for bottom-quark production with transverse momentum greater than 5 GeV is found to be in good agreement with the simplest, lowest-order computations in perturbative quantum chromodynamics. This may be contrasted with the well-known disagreement for the much lighter charm quark. Further checks are discussed.
32381552
Nuclear effects in deep-inelastic lepton scattering.
We present a detailed study of a conventional nuclear model in which the observed differences between the deep-inelastic structure functions of nuclei and of free nucleons, F/sub 2/(x,Q/sup 2/) and q-bar(x,Q/sup 2/), are due to scattering from exchange pions in nuclei associated with the mechanisms responsible for nuclear binding. We assume that the quark and antiquark momentum distributions of these nucleons and pions are unaffected by the nuclear medium. We write the nuclear structure functions as a sum of convolutions of (measured) isolated-hadron structure functions with hadron momentum distributions derived from nuclear potential models. We show that all but one feature of deep-inelastic neutrino and charged-lepton data are reproduced by our model. The exception is the magnitude of the excess above unity of the ratio F/sub 2//sup A/(x)/F/sub 2//sup D/(x) for x<0.2, observed only by the European Muon Collaboration (EMC) experiment. If these EMC data are reduced in normalization by 5%, consistent with experimental uncertainties, then all features of the data are reproduced. We stress the importance of new neutrino and muon measurements at small x.
14220763
Production of a prompt photon in association with a charm quark at next-to-leading order in QCD.
A second order $O({\ensuremath{\alpha}}_{s}^{2})$ calculation in perturbative quantum chromodynamics of the two particle inclusive cross section is presented for the reaction $p+\overline{p}\ensuremath{\rightarrow}\ensuremath{\gamma}+c+X$ for large values of the transverse momentum of the prompt photon and charm quark. The combination of analytic and Monte Carlo integration methods used here to perform phase-space integrations facilitates the imposition of photon isolation restrictions and other selections of relevance in experiments. Differential distributions are provided for various observables. Positive correlations in rapidity are predicted.