35,002 research outputs found
Bc spectroscopy in a quantum-chromodynamic potential model
We have investigated spectroscopy with the use of a
quantum-chromodynamic potential model which was recently used by us for the
light-heavy quarkonia. We give our predictions for the energy levels and the
1 transition widths. We also find, rather surprisingly, that although
is not a light-heavy system, the heavy quark effective theory with the
inclusion of the and corrections is as successful
for as it is for and .Comment: 10 page ReVTeX pape
Heavy Quarkonium Potential Model and the State of Charmonium
A theoretical explanation of the observed splittings among the P~states of
charmonium is given with the use of a nonsingular potential model for heavy
quarkonia. We also show that the recently observed mass difference between the
center of gravity of the states and the state of
does not provide a direct test of the color hyperfine interaction in heavy
quarkonia. Our theoretical value for the mass of the state is in
agreement with the experimental result, and its E1 transition width is
341.8~keV. The mass of the state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen
Quantum-Chromodynamic Potential Model for Light-Heavy Quarkonia and the Heavy Quark Effective Theory
We have investigated the spectra of light-heavy quarkonia with the use of a
quantum-chromodynamic potential model which is similar to that used earlier for
the heavy quarkonia. An essential feature of our treatment is the inclusion of
the one-loop radiative corrections to the quark-antiquark potential, which
contribute significantly to the spin-splittings among the quarkonium energy
levels. Unlike and , the potential for a light-heavy
system has a complicated dependence on the light and heavy quark masses and
, and it contains a spin-orbit mixing term. We have obtained excellent
results for the observed energy levels of , , , and , and
we are able to provide predicted results for many unobserved energy levels. Our
potential parameters for different quarkonia satisfy the constraints of quantum
chromodynamics.
We have also used our investigation to test the accuracy of the heavy quark
effective theory. We find that the heavy quark expansion yields generally good
results for the and energy levels provided that and
corrections are taken into account in the quark-antiquark
interactions. It does not, however, provide equally good results for the energy
levels of and , which indicates that the effective theory can be
applied more accurately to the quark than the quark.Comment: 17 pages of LaTeX. To appear in Physical Review D. Complete
PostScript file is available via WWW at
http://gluon.physics.wayne.edu/wsuhep/jim/heavy.p
Where we stand on structure dependence of ISGMR in the Zr-Mo region: Implications on K_\infty
Isoscalar giant resonances, being the archetypal forms of collective nuclear
behavior, have been studied extensively for decades with the goal of
constraining bulk nuclear properties of the equation of state, as well as for
modeling dynamical behaviors within stellar environments. An important such
mode is the isoscalar electric giant monopole resonance (ISGMR) that can be
understood as a radially symmetric density vibration within the saturated
nuclear volume. The field has a few key open questions, which have been
proposed and remain unresolved. One of the more provocative questions is the
extra high-energy strength in the region, which manifested in
large percentages of the sum rule in Zr and Mo above the
main ISGMR peak. The purpose of this article is to introduce these questions
within the context of experimental investigations into the phenomena in the
zirconium and molybdenum isotopic chains, and to address, via a discussion of
previously published and preliminary results, the implications of recent
experimental efforts on extraction of the nuclear incompressibility from this
data.Comment: 9 pages, 7 figures, invited to be submitted to a special issue of
EPJA honoring Prof. P. F. Bortigno
The Problem of Supply of Coal for the New Steel Plants
WITH depletion of the lower ash, good coking coals occurring in the ripper seams of the Jharia coal field, which were the principal sources of supply of coking
coals for the steel plants in the private sector, atte-ntion was focussed on the need for beneficiation of the higher ash Jharia coals. Three commercial coal washing plants (185 tons/hr. total capacity) were installed in recent years for supplying washed coal to the existing steel plants
On the implications of a dilaton in gauge theory
Some recent work on the implications of a dilaton in 4d gauge theories are
revisited. In part I of this paper we see how an effective dilaton coupling to
gauge kinetic term provides a simple attractive mechanism to generate
confinement. In particular, we put emphasis on the derivation of confining
analytical solutions and look into the problem how dilaton degrees of freedom
modify Coulom potential and when a confining phase occurs. In part II, we solve
the semi-relativistic wave equation, for Dick interquark potential using the
Shifted l-expansion technique (SLET) in the heavy quarkonium sector. The
results of this phenomenological analysis proves that these effective theories
can be relevant to model quark confinement and may shed some light on
confinement mechanism.Comment: 8 pages. Talk given at CTP Symposium on Supersymmetry at LHC:
Theoretical and Experimental Prospectives, Cairo, Egypt, 11-14 Mar 200
Description of Copulatory Complex in Relation to Taxonomy in Gerridae
The family Gerridae is represented in India by 67 species (of which 4 are undescribed species and only known by the nymphs) belonging to 20 genera and representing 7 subfamilies (10 new species are described in the present work). The subfamily Charmatometrinae is not represented in India. The Gerrids or water striders are well known aquatic insects and they are the most interesting and fascinating among all insects of the tropics and subtropics. They skate, skip, glide or literally walk upon the surface of the water. The relation of copulatory complex with taxonomy is described in this research article
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