126219189
Sidereal daily variation of approximately 10-TeV cosmic ray intensity observed by the Tibet air-shower arrays
67782518
Primary proton flux around the "knee" region deduced from the observation of air showers accompanied by gamma families
The simultaneous observation of -families and accompanied air showers enables us to obtain the primary proton flux around the knee energy region where no direct measurements are available up to now. We operated a hy- brid experiment which consists of emulsion chambers and the Tibet-II air-shower array (AS) at Yangbajing (4,300 m a.s.l., 606 g/cm ) in 1996-1999. The total area of emulsion chamber (EC) and burst detector (BD) complex was 80 m and they were set up near the center of the Tibet-II air-shower array. We already published the primary proton flux in the energy region ranging from eV to eV using the BD and AS data. We used an artificial neural network to select the proton-induced events from the EC data set. The proton fluxes obtained from this experiment are presented in the knee energy region. Our result suggests that the primary becomes heavy dominant in the knee energy region.
53311398
Chiral extrapolation of nucleon magnetic form factors
The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer (${Q}^{2}$), a separate extrapolation to the physical pion mass is carried out as a function of ${m}_{\ensuremath{\pi}}$ alone. Because of the large values of ${Q}^{2}$ involved, the role of the pion form factor in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of ${Q}^{2}$ and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.
18625699
Measurement of the cosmic ray e+ +e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope.
Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 m;{2} sr at 300 GeV. Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply falling electron spectrum up to 1 TeV. Our high precision data show that the electron spectrum falls with energy as E-3.0 and does not exhibit prominent spectral features. Interpretations in terms of a conventional diffusive model as well as a potential local extra component are briefly discussed.
24427533
Observation of anomalous upsilon(1S)pi+pi(-) and upsilon(2S)pi+pi(-) production near the upsilon(5S) resonance.
We report the first observation of e;{+}e;{-}-->Upsilon(1S)pi;{+}pi;{-}, Upsilon(2S)pi;{+}pi;{-}, and first evidence for e;{+}e;{-}-->Upsilon(3S)pi;{+}pi;{-}, Upsilon(1S)K+K-, near the peak of the Upsilon(5S) resonance at sqrt[s] approximately 10.87 GeV. The results are based on a data sample of 21.7 fb;{-1} collected with the Belle detector at the KEKB e;{+}e;{-} collider. Attributing the signals to the Upsilon(5S) resonance, the partial widths Gamma(Upsilon(5S)-->Upsilon(1S)pi;{+}pi;{-})=0.59+/-0.04(stat)+/-0.09(syst) MeV and Gamma(Upsilon(5S)-->Upsilon(2S)pi;{+}pi;{-})=0.85+/-0.07(stat)+/-0.16(syst) MeV are obtained from the observed cross sections. These values exceed by more than 2 orders of magnitude the previously measured partial widths for dipion transitions between lower Upsilon resonances.
123828218
Measurement of the $B^0 \to \pi^{-} \ell^{+} \nu$ and $B^{+} \to \pi^0 \ell^{+} \nu$ branching fractions and determination of $|V_{ub}|$ in $\upsilon_{4S} \to B \bar{B}$ events tagged by a fully reconstructed $B$ meson
The authors report preliminary measurements of the charmless exclusive semileptonic branching fractions of the B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} and B{sup +} {yields} {pi}{sup 0}{ell}{sup +}{nu} decays, based on 211 fb{sup -1} of data collected at the {Upsilon}(4S) resonance by the BABAR detector. In events in which the decay of one B meson to a hadronic final state is fully reconstructed, the semileptonic decay of the second B meson is identified by the detection of a charged lepton and a pion. They measure the partial branching fractions for B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} and B{sup +} {yields} {pi}{sup 0}{ell}{sup +}{nu} in three regions of the invariant mass squared of the lepton pair, and they obtain the total branching fractions {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.14 {+-} 0.27{sub stat} {+-} 0.17{sub syst}) x 10{sup -4} and {Beta}(B{sup +} {yields} {pi}{sup 0}{ell}{sup +}{nu}) = (0.86 {+-} 0.22{sub stat} {+-} 0.11{sub syst}) x 10{sup -4}. Using isospin symmetry, they measure the combined total branching fraction {Beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.28 {+-} 0.23{sub stat} {+-} 0.16{sub syst}) x 10{sup -4}. Theoretical predictions of the form-factor are used to determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |V{submore » ub}| = (3.7 {+-} 0.3{sub stat} {+-} 0.2{sub syst{sub -0.5FF}{sup +0.8}}) x 10{sup -3}, where the last uncertainty is due to the form-factor normalization.« less
116694165
Measurement of $\sin(2\beta)$ using hadronic $J/\psi$ decays
The authors report a measurement of the CP-violation parameter sin2{beta} with B{sup 0} {yields} J/{phi}K{sub S}{sup 0} decays in which the J/{psi} decays to hadrons. With a sample of 88 million B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, they reconstruct 100 {+-} 17 such events, with J/{psi} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup 0} being the most prevalent, and measure sin 2{beta} = 1.56 {+-} 0.42(stat.) {+-} 0.21(syst.).