485 research outputs found
Light Quark Resonances in pbar p Annihilations at 5.2 GeV/c
Data from the Fermilab E835 experiment have been used to study the reaction
pbar p -> eta eta pi0 at 5.2 GeV/c. A sample of 22 million six photons events
has been analyzed to construct the Dalitz plot containing ~80k eta eta pi0
events. A partial wave analysis of the data has been done. Six f_J-states
decaying into eta eta and five a_J-states decaying into eta pi0 are identified
in the mass region ~1.3 and 2.4 GeV, and their masses, widths and spins are
determined by maximum likelihood analysis of the data. Two f_0 states are
identified with the popular candidates for the lightest scalar glueball,
f_0(1500) and f_0(1710).Comment: 7 pages, 6 figure
Search for X(3872) in gamma gamma Fusion and ISR at CLEO
We report on a search for the X(3872) state using 15.1 fb^{-1} of e+ e-
annihilation data taken with the CLEO III detector in the sqrt{s} = 9.46-11.30
GeV region. Separate searches for the production of X(3872) in untagged gamma
gamma fusion and e+ e- annihilation following initial state radiation are made
by taking advantage of the unique correlation of J/psi -> l+ l- in X(3872)
decay into J/psi pi+ pi-. No signals are observed in either case, and 90%
confidence upper limits are established as (2J+1)Gamma_{gammagamma}(X(3872))B(X
-> J/psi pi+ pi-) J/psi pi+ pi-) < 8.3
eV.Comment: 4 pages, 2 figures, to appear in the proceedings of the 1st Meeting
of the APS Topical Group on Hadronic Physics, Fermilab, Oct. 24-26, 200
Charm Leptonic and Semileptonic Decays
Experimental results for the pseudoscalar decay constants f_{D} and f_{D_s}
are reviewed. Semileptonic form factor results from D -> (pseudoscalar) l nu
and D -> (vector) l nu decays are also reviewed.Comment: 8 pages, 4 figures, presented at the 11th International Conference on
B-Physics at Hadron Machines (BEAUTY 2006) Sept. 25-29, Oxford, England;
corrected typo
New Results From CLEO and BES
Latest experimental results from BES in the charmonium mass region, and those
from CLEO in the bottomonium and charmonium spectroscopy are reviewed.Comment: 12 pages, 12 figures, Presented at First Meeting of the APS Topical
Group on Hadron Physics, Fermilab, Batavia, Illinois, Oct 24-26, 200
Interference Study of the chi_c0 (1^3P_0) in the Reaction Proton-Antiproton -> pi^0 pi^0
Fermilab experiment E835 has observed proton-antiproton annihilation
production of the charmonium state chi_c0 and its subsequent decay into pi^0
pi^0. Although the resonant amplitude is an order of magnitude smaller than
that of the non-resonant continuum production of pi^0 pi^0, an enhanced
interference signal is evident. A partial wave expansion is used to extract
physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate
the expansion. Both are accessed by L=1 in the entrance proton-antiproton
channel. The product of the input and output branching fractions is determined
to be B(pbar p -> chi_c0) x B(chi_c0 -> pi^0 pi^0)= (5.09 +- 0.81 +- 0.25) x
10^-7.Comment: 4 pages, 4 figures, Accepted by PRL (July 2003
Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in antiproton-proton annihilations
We present new precision measurements of the psi(2S) total and partial widths
from excitation curves obtained in antiproton-proton annihilations by Fermilab
experiment E835 at the Antiproton Accumulator in the year 2000. A new technique
of complementary scans was developed to study narrow resonances with
stochastically cooled antiproton beams. The technique relies on precise
revolution-frequency and orbit-length measurements, while making the analysis
of the excitation curve almost independent of machine lattice parameters. We
study the psi(2S) meson through the processes pbar p -> e+ e- and pbar p ->
J/psi + X -> e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +-
4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp /
Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise
measurements to date.Comment: 17 pages, 3 figures, 3 tables. Final manuscript accepted for
publication in Phys. Lett. B. Parts of the text slightly expanded or
rearranged; results are unchange
Measuring V_ub and probing SUSY with double ratios of purely leptonic decays of B and D mesons
The experimental prospects for precise measurements of the leptonic decays
B_u -> tau nu / mu nu, B_s -> mu+ mu-, D -> mu nu and D_s -> mu nu / tau nu are
very promising. Double ratios involving four of these decays can be defined in
which the dependence on the values of the decay constants is essentially
eliminated, thus enabling complementary measurements of the CKM matrix element
V_ub with a small theoretical error. We quantify the experimental error in a
possible future measurement of |V_ub| using this approach, and show that it is
competitive with the anticipated precision from the conventional approaches.
Moreover, it is shown that such double ratios can be more effective than the
individual leptonic decays as a probe of the parameter space of supersymmetric
models. We emphasize that the double ratios have the advantage of using |V_ub|
as an input parameter (for which there is experimental information), while the
individual decays have an uncertainty from the decay constants (e.g. f_B_s),
and hence a reliance on theoretical techniques such as lattice QCD.Comment: 21 pages, 4 figure
Search for rare and forbidden decays of charm and charmed-strange mesons to final states h^+- e^-+ e^+
We have searched for flavor-changing neutral current decays and
lepton-number-violating decays of D^+ and D^+_s mesons to final states of the
form h^+- e^-+ e^+, where h is either \pi or K. We use the complete samples of
CLEO-c open-charm data, corresponding to integrated luminosities of 818 pb^-1
at the center-of-mass energy E_CM = 3.774 GeV containing 2.4 x 10^6 D^+D^-
pairs and 602 pb^-1 at E_CM = 4.170 GeV containing 0.6 x 10^6 D^*+-_s D^-+_s
pairs. No signal is observed in any channel, and we obtain 90% confidence level
upper limits on branching fractions B(D^+ --> \pi^+ e^+ e^-) < 5.9 x 10^-6,
B(D^+ --> \pi^- e^+ e^+) K^+ e^+ e^-) < 3.0 x 10^-6,
B(D^+ --> K^- e^+ e^+) \pi^+ e^+ e^-) < 2.2 x 10^-5,
B(D^+_s --> \pi^- e^+ e^+) K^+ e^+ e^-) < 5.2 x
10^-5, and B(D^+_s --> K^- e^+ e^+) < 1.7 x 10^-5.Comment: 9 pages, available through http://www.lns.cornell.edu/public/CLNS
Theoretical Overview: The New Mesons
After commenting on the state of contemporary hadronic physics and
spectroscopy, I highlight four areas where the action is: searching for the
relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and
the D_{sJ} levels, and X(3872) and the lost tribes of charmonium.Comment: 10 pages, uses jpconf.cls; talk at First Meeting of the APS Topical
Group on Hadronic Physic
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