104 research outputs found
Radiative Scalar Meson Decays in the Light-Front Quark Model
We construct a relativistic wavefunction for scalar mesons within the
framework of light-front quark model(LFQM). This scalar wavefunction is used to
perform relativistic calculations of absolute widths for the radiative decay
processes, and
which incorporate the effects of glueball-
mixing. The mixed physical states are assumed to be ,and
for which the flavor-glue content is taken from the mixing
calculations of other works. Since experimental data for these processes are
poor, our results are compared with those of a recent non-relativistic model
calculation. We find that while the relativistic corrections introduced by the
LFQM reduce the magnitudes of the decay widths by 50-70%, the relative
strengths between different decay processes are fairly well preserved. We also
calculate decay widths for the processes and
(0^{++})\to\gamma\gamm involving the light scalars and
to test the simple model of these mesons. Our results of
model for these processes are not quite consistent with well-established data,
further supporting the idea that and are not conventional
states.Comment: 10 pages, 4 figure
Energetics and Possible Formation and Decay Mechanisms of Vortices in Helium Nanodroplets
The energy and angular momentum of both straight and curved vortex states of
a helium nanodroplet are examined as a function of droplet size. For droplets
in the size range of many experiments, it is found that during the pickup of
heavy solutes, a significant fraction of events deposit sufficient energy and
angular momentum to form a straight vortex line. Curved vortex lines exist down
to nearly zero angular momentum and energy, and thus could in principle form in
almost any collision. Further, the coalescence of smaller droplets during the
cooling by expansion could also deposit sufficient angular momentum to form
vortex lines. Despite their high energy, most vortices are predicted to be
stable at the final temperature (0.38 K) of helium nanodroplets due to lack of
decay channels that conserve both energy and angular momentum.Comment: 10 pages, 8 figures, RevTex 4, submitted to Phys. Rev.
Parton content of the real photon: astrophysical implications
We possess convincing experimental evidence for the fact that the real photon
has non-trivial parton structure. On the other hand, interactions of the cosmic
microwave background photons with high energy particles propagating through the
Universe play an important role in astrophysics. In this context, to invoke the
parton content could be convenient for calculations of the probabilities of
different processes involving these photons. As an example, the cross section
of inclusive resonant boson production in the reaction is calculated by using the parton language. Neutrino--photon deep
inelastic scattering is considered.Comment: 4 pages, 2 figures. The spin states of the initial particles in the
reaction are correctly treated. As a result, the
corresponding cross section becomes two times greater than the one from the
previous version. Some changes in the tex
Scalar Particles in Lattice QCD
We report a project to study scalar particles by lattice QCD simulations.
After a brief introduction of the current situation of lattice study of the
sigma meson, we describe our numerical simulations of scalar mesons,
and . We observe a low sigma mass, , for
which the disconnected diagram plays an important role. For the kappa meson, we
obtain higher mass than the experimental value, i.e., .Comment: 4 figures, to be published in Proceedings of `International Symposium
on Hadron Spectroscopy, Chiral Symmetry and Relativistic Description of Bound
Systems' (in a series of KEK proceedings
Nuclear shadowing at low Q^2
We re-examine the role of vector meson dominance in nuclear shadowing at low
Q^2. We find that models which incorporate both vector meson and partonic
mechanisms are consistent with both the magnitude and the Q^2 slope of the
shadowing data.Comment: 7 pages, 2 figures; to appear in Phys. Rev.
Correlations and Fluctuations in High-Energy Nuclear Collisions
Nucleon correlations in the target and projectile nuclei are shown to reduce
significantly the fluctuations in multiple nucleon-nucleon collisions, total
multiplicity and transverse energy in relativistic heavy-ion collisions, in
particular for heavy projectile and target. The interplay between cross-section
fluctuations, from color transparency and opacity, and nuclear correlations is
calculated and found to be able to account for large fluctuations in transverse
energy spectra. Numerical implementation of correlations and cross-section
fluctuations in Monte-Carlo codes is discussed.Comment: 30 pages, in Revtex, plus 4 figures. Figures and preprint can be
obtained by mailing address to: [email protected]
Light Quark Masses in Multi-Quark Interactions
We suggest and discuss in detail a multi-quark three flavor Lagrangian of the
Nambu -- Jona-Lasinio type, which includes a set of effective interactions
proportional to the current quark masses. It is shown that within the dynamical
chiral symmetry breaking regime, the masses of the pseudo Goldstone bosons and
their chiral partners, members of the low lying scalar nonet, are in perfect
agreement with current phenomenological expectations. The role of the new
interactions is analyzed.Comment: 8 pages, published versio
Dilepton Spectra from Decays of Light Unflavored Mesons
The invariant mass spectrum of the and pairs
from decays of light unflavored mesons with masses below the -meson mass to final states containing along with a dilepton pair one
photon, one meson, and two mesons are calculated within the framework of the
effective meson theory. The results can be used for simulations of the dilepton
spectra in heavy-ion collisions and for experimental searches of dilepton meson
decays.Comment: 73 pages, 19 figures, 3 tables, REVTeX, new references adde
The use of low energy, ion induced nuclear reactions for proton radiotherapy applications
Prospects for e+e- physics at Frascati between the phi and the psi
We present a detailed study, done in the framework of the INFN 2006 Roadmap,
of the prospects for e+e- physics at the Frascati National Laboratories. The
physics case for an e+e- collider running at high luminosity at the phi
resonance energy and also reaching a maximum center of mass energy of 2.5 GeV
is discussed, together with the specific aspects of a very high luminosity
tau-charm factory. Subjects connected to Kaon decay physics are not discussed
here, being part of another INFN Roadmap working group. The significance of the
project and the impact on INFN are also discussed. All the documentation
related to the activities of the working group can be found in
http://www.roma1.infn.it/people/bini/roadmap.html.Comment: INFN Roadmap Report: 86 pages, 25 figures, 9 table
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