3,081 research outputs found
Lambda hyperonic effect on the normal driplines
A generalized mass formula is used to calculate the neutron and proton drip
lines of normal and lambda hypernuclei treating non-strange and strange nuclei
on the same footing. Calculations suggest existence of several bound
hypernuclei whose normal cores are unbound. Addition of Lambda or,
Lambda-Lambda hyperon(s) to a normal nucleus is found to cause shifts of the
neutron and proton driplines from their conventional limits.Comment: 6 pages, 4 tables, 0 figur
Sensitivity to neutrino mixing parameters with atmospheric neutrinos
We have analyzed the atmospheric neutrino data to study the octant of
and the precision of the oscillation parameters for a large Iron
CALorimeter (ICAL) detector. The ICAL being a tracking detector has the ability
to measure the energy and the direction of the muon with high resolution. From
bending of the track in magnetic field it can also distinguish its charge. We
have generated events by Nuance and then considered only the muons (directly
measurable quantities) produced in charge current interactions in our analysis.
This encounters the main problem of wide resolutions of energy and baseline.
The energy-angle correlated two dimensional resolution functions are used to
migrate the energy and the zenith angle of the neutrino to those of the muon. A
new type of binning has been introduced to get better reflection of the
oscillation pattern in chi-square analysis. Then the marginalization of the
over all parameters has been carried out for neutrinos and
anti-neutrinos separately. We find that the measurement of is
possible at a significant precision with atmospheric neutrinos. The precisions
of and are found 8% and 38%,
respectively, at 90% CL. The discrimination of the octant as well as the
deviation from maximal mixing of atmospheric neutrinos are also possible for
some combinations of (). We also discuss the impact
of the events at near horizon on the precision studies.Comment: 16 pages, 12 figures, new results added; accepted for publication in
Phys. Rev.
The Shear Viscosity in Anisotropic Phases
We construct anisotropic black brane solutions and analyse the behaviour of
some of their metric perturbations. These solutions correspond to field theory
duals in which rotational symmetry is broken due an externally applied,
spatially constant, force. We find, in several examples, that when the
anisotropy is sufficiently big compared to the temperature, some components of
the viscosity tensor can become very small in units of the entropy density,
parametrically violating the KSS bound. We obtain an expression relating these
components of the viscosity, in units of the entropy density, to a ratio of
metric components at the horizon of the black brane. This relation is generally
valid, as long as the forcing function is translationally invariant, and it
directly connects the parametric violation of the bound to the anisotropy in
the metric at the horizon. Our results suggest the possibility that such small
components of the viscosity tensor might also arise in anisotropic strongly
coupled fluids found in nature.Comment: 30 pages + 4 page appendix, 3 figures, added reference
Isobaric incompressibility of the isospin asymmetric nuclear matter
The isospin dependence of the saturation properties of asymmetric nuclear
matter, particularly the incompressibility at saturation density is systematically studied using density
dependent M3Y interaction. The characterizes the isospin dependence of
the incompressibility at saturation density . The approximate
expression is often used for where
and represent, respectively, the slope and curvature parameters of
the symmetry energy at . It can be expressed accurately as
where is the third-order
derivative parameter of symmetric nuclear matter at . The results of
this addendum to Phys. Rev. C 80, 011305(R) (2009) indicate that the
contribution to is not insignificant.Comment: 4 pages including 1 table and 1 figur
A Mass Formula from Light to Hypernuclei
Simultaneous description of ordinary and hypernuclei masses by a single mass
formula has been a great challenge in nuclear physics. Hyperon-separation
energies of about forty Lambda(), three
Lambda-Lambda(), one Sigma() and seven Cascade()
hypernuclei have been experimentally found. Many of these nuclei are of light
masses. We prescribe a new mass formula, called BWMH, which describes the
normal and hypernuclei on the same footing. It is based on the
modified-Bethe-Weizs\"acker mass formula (BWM). BWM is basically an extension
of the Bethe-Weizs\"acker mass formula (BW) for light nuclei. The parameters of
BWM were optimized by fitting about 3000 normal nuclei available recently. The
original Bethe-Weizs\"acker mass formula (BW) was designed for medium and heavy
mass nuclei and it fails for light nuclei. Two earlier works on hypernuclei
based on this BW show some limitations. The BWMH gives improved agreement with
the experimental data for the line of stability, one-neutron separation energy
versus neutron number spectra of normal nuclei, and the hyperon-separation
energies from hypernuclei. The drip lines are modified for addition of a
hyperon in a normal nucleus.Comment: Presented at the "XXIX Mazurian Lakes Conference on Physics: Nuclear
Physics and the Fundamental Processes, Piaski, Poland, August 30 - September
6, 2005." (7 pages, 1 Table, 1 Figure
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