630,466 research outputs found
Study of psi(2S) decays to X J/psi
Using J/psi -> mu^+ mu^- decays from a sample of approximately 4 million
psi(2S) events collected with the BESI detector, the branching fractions of
psi(2S) -> eta J/psi, pi^0 pi^0 J/psi, and anything J/psi normalized to that of
psi(2S) -> pi^+ pi^- J/psi are measured. The results are B(psi(2S) -> eta
J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.098 \pm 0.005 \pm 0.010, B(psi(2S) ->
pi^0 pi^0 J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 0.570 \pm 0.009 \pm 0.026, and
B(psi(2S) -> anything J/psi)/B(psi(2S) -> pi^+ pi^- J/psi) = 1.867 \pm 0.026
\pm 0.055.Comment: 13 pages, 8 figure
Measurement of Gamma_ee(J/psi), Gamma_tot(J/psi), and Gamma_ee[psi(2S)]/Gamma_ee(J/psi)
Using data acquired with the CLEO detector at the CESR e+e- collider at
sqrt{s} = 3.773 GeV, we measure the cross section for the radiative return
process e+e- --> gamma J/psi, J/psi --> mu+mu-, resulting in B(J/psi -->
mu+mu-) x Gamma_ee(J/psi) = 0.3384 +- 0.0058 +- 0.0071 keV, Gamma_ee(J/psi) =
5.68 +- 0.11 +- 0.13 keV, and Gamma_tot(J/psi) = 95.5 +- 2.4 +- 2.4 keV, in
which the errors are statistical and systematic, respectively. We also
determine the ratio Gamma_ee[psi(2S)] / Gamma_ee(J/psi) = 0.45 +- 0.01 +- 0.02.Comment: 12 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2005
Spectral Degeneracy in Supersymmetric Gluodynamics and One-Flavor QCD related to N=1/2 SUSY
In supersymmetric gluodynamics (N=1 super-Yang-Mills theory) we show that the
spectral functions induced by the nonchiral operator Tr G_{\alpha\beta}
\bar\lambda^2 are fully degenerate in the J^{PC}=1^{\pm -} channels. The above
operator is related to N=1/2 generalization of SUSY. Using the planar
equivalence, this translates into the statement of degeneracy between the
mesons produced from the vacuum by the operators (\bar \Psi \vec E\Psi + i\bar
\Psi \vec B \gamma^5\Psi) and (\bar \Psi \vec B\Psi - i\bar \Psi \vec E
\gamma^5\Psi) in one-flavor QCD, up to 1/N corrections. Here \Psi is the quark
field, and \vec E ,\vec B are chromoelectric/chromomagnetic fields,
respectively.Comment: Latex, 6 pages, two references adde
Relative rates of B meson decays into psi(2S) and J/psi mesons
We report on a study of the relative rates of B meson decays into psi(2S) and J/psi mesons using 1.3 fb^-1 of pbar p collisions at sqrt(s) = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B^0_s -> psi(2S)phi, B^0_s -> J/psi phi, B^+/- -> psi(2S) K^+/-, and B^+/- -> J/psi K^+/- and we measure the relative branching fractions for these channels to be B(B^0_s -> psi(2S)phi)/B(B^0_s -> J/psi phi) = 0.55 +/- 0.11 (stat) +/- 0.07 (syst) +/- 0.06 (B), B(B^+/- -> psi(2S) K^+/-)/B(B^+/- -> J/psi K^+/-) = 0.65 +/- 0.04 (stat) +/- 0.03 (syst) +/- 0.07 (B) where the final error corresponds to the uncertainty in the J/psi and psi(2S) branching ratio into two muons
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