411 research outputs found
Covariant scalar representation of quantization of the scalar relativistic particle
A covariant scalar representation of is constructed and
analysed in comparison with existing methods for the quantization of the scalar
relativistic particle. It is found that, with appropriately defined
wavefunctions, this produced representation can be identified
with the state space arising from the canonical BFV-BRST quantization of the
modular invariant, unoriented scalar particle (or antiparticle) with admissible
gauge fixing conditions. For this model, the cohomological determination of
physical states can thus be obtained purely from the representation theory of
the algebra.Comment: 16 pages Late
Hamiltonian Noether theorem for gauge systems and two time physics
The Noether theorem for Hamiltonian constrained systems is revisited. In
particular, our review presents a novel method to show that the gauge
transformations are generated by the conserved quantities associated with the
first class constraints. We apply our results to the relativistic point
particle, to the Friedberg et al. model and, with special emphasis, to two time
physics.Comment: 20 pages, Latex, references added, the "massless" sense of (87) is
clarifie
Radiative correction of the correlator for (0^{++},1) light hybrid
We calculate the radiative corrections to the current-current correlator of
the hybrid current . Based on this
new result we use the QCD sum rule approach to estimate lower bounds on the
masses of the = and light hybrids.Comment: References added and Text improve
Symmetries and dynamics in constrained systems
We review in detail the Hamiltonian dynamics for constrained systems.
Emphasis is put on the total Hamiltonian system rather than on the extended
Hamiltonian system. We provide a systematic analysis of (global and local)
symmetries in total Hamiltonian systems. In particular, in analogue to total
Hamiltonians, we introduce the notion of total Noether charges. Grassmannian
degrees of freedom are also addressed in details.Comment: 1+97 pages, No figure, Expanded version of a lecture note by J.-H.
Park at Sogang University, Seoul during 2007-2008. Accepted for publication
in the European Physical Journal C as a review article; Reference adde
Hybrid and Conventional Mesons in the Flux Tube Model: Numerical Studies and their Phenomenological Implications
We present results from analytical and numerical studies of a flux tube model
of hybrid mesons. Our numerical results use a Hamiltonian Monte Carlo algorithm
and so improve on previous analytical treatments, which assumed small flux tube
oscillations and an adiabatic separation of quark and flux tube motion. We find
that the small oscillation approximation is inappropriate for typical hadrons
and that the hybrid mass is underestimated by the adiabatic approximation. For
physical parameters in the ``one-bead" flux tube model we estimate the lightest
hybrid masses ( states) to be 1.8-1.9~GeV for
hybrids, 2.1-2.2~GeV for and 4.1-4.2~GeV for . We also
determine masses of conventional mesons with to in this
model, and confirm good agreement with experimental -averaged multiplet
masses. Mass estimates are also given for hybrids with higher orbital and
flux-tube excitations. The gap from the lightest hybrid level () to the
first hybrid orbital excitation () is predicted to be ~GeV
for light quarks and ~GeV for . Both and
hybrid multiplets contain the exotics and ; in
addition the has a and the contains a . Hybrid
mesons with doubly-excited flux tubes are also considered. The implications of
our results for spectroscopy are discussed, with emphasis on charmonium
hybrids, which may be accessible at facilities such as BEPC, KEK, a Tau-Charm
Factory, and in production at hadron colliders.Comment: 39 pages of RevTex. Figures available via anonymous ftp at
ftp://compsci.cas.vanderbilt.edu/QSM/bcsfig1.ps and /QSM/bcsfig6.p
The Nucleon's Tensor Charge
We seek to understand the physical significance of the nucleon's tensor
charge and make estimates of its size in phenomenological models and the QCD
sum rule.Comment: 8 pages, ReVTe
The hybrid meson: new results from the updated mg and alpha_s parameters
We present new results concerning the masses and the decay widths of the most
interesting hybrid meson states taking as inputs the gluon mass mg and the
non-perturbative QCD running coupling constant ?alpha_s(0) comming from both
LQCD and SDE recent estimations.Comment: 10 pages, 8 table
Observation of exotic meson production in the reaction at 18 GeV/c
An amplitude analysis of an exclusive sample of 5765 events from the reaction
at 18 GeV/c is described. The
production is dominated by natural parity exchange and by
three partial waves: those with and . A
mass-dependent analysis of the partial-wave amplitudes indicates the production
of the meson as well as the meson, observed for the
first time decaying to . The dominant, exotic
(non- partial wave is shown to be resonant with a mass of
GeV/c^2 and a width of GeV/c^2 . This exotic state, the , is produced with a
dependence which is different from that of the meson, indicating
differences between the production mechanisms for the two states.Comment: 5 pages with 4 figure
Induced pseudoscalar coupling of the proton weak interaction
The induced pseudoscalar coupling is the least well known of the weak
coupling constants of the proton's charged--current interaction. Its size is
dictated by chiral symmetry arguments, and its measurement represents an
important test of quantum chromodynamics at low energies. During the past
decade a large body of new data relevant to the coupling has been
accumulated. This data includes measurements of radiative and non radiative
muon capture on targets ranging from hydrogen and few--nucleon systems to
complex nuclei. Herein the authors review the theoretical underpinnings of
, the experimental studies of , and the procedures and uncertainties
in extracting the coupling from data. Current puzzles are highlighted and
future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic
Search for a 33.9 MeV/c^2 Neutral Particle in Pion Decay
The E815 (NuTeV) neutrino experiment has performed a search for a 33.9
MeV/c^2 weakly-interacting neutral particle produced in pion decay. Such a
particle may be responsible for an anomaly in the timing distribution of
neutrino interactions in the KARMEN experiment. E815 has searched for this
particle's decays in an instrumented decay region; no evidence for this
particle was found. The search is sensitive to pion branching ratios as low as
10^-13.Comment: 4 pages; 5 figure
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