174 research outputs found
The Baksan gallium solar neutrino experiment
A radiochemical 71Ga-71Ge experiment to determine the integral flux of neutrinos from the sun has been constructed at the Baksan Neutrino Observatory in the USSR. Measurements have begun with 30 tonnes of gallium. An additional 30 tonnes of gallium are being installed so as to perform the full experiment with a 60-tonne target. The motivation, experiment procedures, and present status of this experiment are described. © 1990
First results from the Soviet-American gallium experiment
The Soviet-American Gallium Experiment is the first experiment able to measure the dominant flux of low energy p-p solar neutrinos. Four extractions made during January to May 1990 from 30 tons of gallium have been counted and indicate that the flux is consistent with 0 SNU and is less than 72 SNU (68% CL) and less than 138 SNU (95% CL). This is to be compared with the flux of 132 SNU predicted by the Standard Solar Model. © 1991
The physics of dipolar bosonic quantum gases
This article reviews the recent theoretical and experimental advances in the
study of ultracold gases made of bosonic particles interacting via the
long-range, anisotropic dipole-dipole interaction, in addition to the
short-range and isotropic contact interaction usually at work in ultracold
gases. The specific properties emerging from the dipolar interaction are
emphasized, from the mean-field regime valid for dilute Bose-Einstein
condensates, to the strongly correlated regimes reached for dipolar bosons in
optical lattices.Comment: Review article, 71 pages, 35 figures, 350 references. Submitted to
Reports on Progress in Physic
Measurement of eta_c(1S), eta_c(2S) and non-resonant eta' pi+ pi- production via two-photon collisions
We report the measurement of gamma gamma to eta_c(1S), eta_c(2S) to eta' pi+
pi- with eta' decays to gamma rho and eta pi+ pi- using 941 fb^{-1} of data
collected with the Belle detector at the KEKB asymmetric-energy e+e- collider.
The eta_c(1S) mass and width are measured to be M = [2984.6\pm0.7 (stat.)\pm2.2
(syst.)] MeV/c^{2} and \Gamma = [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)]
MeV, respectively. First observation of eta_c(2S) to eta' pi+ pi- with a
significance of 5.5sigma including systematic error is obtained, and the
eta_c(2S) mass is measured to be M = [3635.1\pm3.7~(stat.)\pm2.9~(syst.)]
MeV/c^{2}. The products of the two-photon decay width and branching fraction
(B) of decays to eta'pi+ pi- are determined to be \Gamma_{gamma gamma}B =
[65.4\pm2.6~(stat.)\pm6.9~(syst.)] eV for eta_c(1S) and
[5.6^{+1.2}_{-1.1}~(stat.)\pm1.1~(syst.)] eV for eta_c(2S). A new decay mode
for the eta_c(1S) to eta'f_0(2080) with f_0(2080) to pi+ pi- is observed with a
statistical significance of 20sigma. The f_0(2080) mass and width are
determined to be M = [2083^{+63}_{-66}~(stat.)\pm 32~(syst.)] MeV/c^{2} and
\Gamma = [178^{+60}_{-178}~(stat.) \pm 55~(syst.)] MeV. The cross sections for
gamma gamma to eta' pi+ pi- and eta'f_{2}(1270) are measured for the first
time.Comment: 19 pages, 14 figure
Measurement of Branching Fractions of Hadronic Decays of the Baryon
Using a data sample of 980 of annihilation data
taken with the Belle detector operating at the KEKB asymmetric-energy
collider, we report the results of a study of the decays of the
charmed baryon into hadronic final states. We report the most precise
measurements to date of the relative branching fractions of the
into , , , and
, as well as the first measurements of the branching fractions
of the into , , and , all with respect to the decay. In
addition, we investigate the resonant substructure of these modes. Finally, we
present a limit on the branching fraction for the decay
Inclusive study of bottomonium production in association with an meson in annihilations near
We study bottomonium production in association with an meson in
annihilations near the , at a center of mass energy of
GeV. The results are based on the fb data
sample collected by the Belle experiment at the asymmetric energy KEKB
collider. Only the meson is reconstructed and the missing-mass spectrum
of candidates is investigated. We observe the
process and find evidence for the
process, while no significant signals of
, , nor are found. Cross sections for the
studied processes are reported.Comment: Submitted to EPJ-
Measurement of the lepton polarization and in the decay with one-prong hadronic decays at Belle
With the full data sample of pairs recorded by
the Belle detector at the KEKB electron-positron collider, the decay is studied with the hadronic
decays and . The polarization in two-body hadronic
decays is measured, as well as the ratio of the branching fractions , where
denotes an electron or a muon. Our results, and , are consistent with the theoretical
predictions of the Standard Model. The polarization values of are excluded at the 90\% confidence level.Comment: 17 pages, 11 figures, submitted to Physical Review
Recommended from our members
The Soviet-American gallium experiment at Baksan
A gallium solar neutrino detector is sensitive to the full range of the solar neutrino spectrum, including the low-energy neutrinos from the fundamental proton-proton fusion reaction. If neutrino oscillations in the solar interior are responsible for the suppressed {sup 8}B flux measured by the Homestake {sup 37}Cl experiment and the Kamiokande water Cherenkov detector, then a comparison of the gallium, chlorine, and water results may make possible a determination of the neutrino mass difference and mixing angle. A 30-ton gallium detector is currently operating in the Baksan laboratory in the Soviet Union, with a ratio of expected solar signal to measured background (during the first one to two {sup 71}Ge half lives) of approximately one. 28 refs
Search for violation in the decay at Belle
We search for violation in the charged charm meson decay
, based on a data sample corresponding to an integrated
luminosity of collected by the Belle experiment at the KEKB
asymmetric-energy collider. The measured violating asymmetry
is , which is consistent with
the standard model prediction and has a significantly improved precision
compared to previous results.Comment: 8 pages, 3 figure
Nuclear-Medium Modification of the Rho(1S)- and Rhoprim(2S)-Mesons in Coherent Photo- and Electroproduction: Coupled Channel Analysis
We study medium modifications of the dilepton mass spectrum in coherent
photo- and electroproduction of the Rho(1S)- and Rhoprim(2S)-meson resonances
on nuclear targets. The analysis is performed within the coupled Rho,
Rhoprim... channel formalism in which nuclear modifications derive from the
off-diagonal rescatterings. We find that the effect of off-diagonal
rescatterings on the shape of the dilepton mass spectrum in the Rho(1S)-meson
mass region is only marginal but is very important in the Rhoprim mass region.
The main off-diagonal contribution in the Rhoprim mass region comes from the
sequential mechanism gamma* -> Rho -> Rhoprim(2S), which dominates the
Rhoprim(2S) production for heavy nuclei.
Our results show also that in the Rhoprim(2S) mass region there is a
considerable effect of the interference of the Breit-Wigner tail of
Rho(1S)-meson with the Rhoprim-meson.Comment: 18 pages, 9 figure
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