4,379 research outputs found
Pair Production of Fourth Family Charged Sleptons at Colliders
We study the pair production of , which is the supersymmetric
partner of the fourth family charged lepton, at the colliders. It
is shown that the investigation of this process at ILC/CLIC will give
opportunity to differentiate the MSSM with three and four families.Comment: 6 pages, 2 figure
Wormhole with varying cosmological constant
It has been suggested that the cosmological constant is a variable dynamical
quantity. A class of solution has been presented for the spherically symmetric
space time describing wormholes by assuming the erstwhile cosmological constant
to be a space variable scalar, viz., = . It
is shown that the Averaged Null Energy Condition (ANEC) violating exotic matter
can be made arbitrarily small.Comment: 8 pages, 2 figures, Accepted in Gen. Rel. Gra
Quantum Phase Shift in Chern-Simons Modified Gravity
Using a unified approach of optical-mechanical analogy in a semiclassical
formula, we evaluate the effect of Chern-Simons modified gravity on the quantum
phase shift of de Broglie waves in neutron interferometry. The phase shift
calculated here reveals, in a single equation, a combination of effects coming
from Newtonian gravity, inertial forces, Schwarzschild and Chern-Simons
modified gravity. However the last two effects, though new, turn out to be too
tiny to be observed, and hence only of academic interest at present. The
approximations, wherever used, as well as the drawbacks of the non-dynamical
approach are clearly indicated.Comment: 16 pages, minor errors corrected. Accepted for publication in Phys.
Rev.
Can electro-magnetic field, anisotropic source and varying be sufficient to produce wormhole spacetime ?
It is well known that solutions of general relativity which allow for
traversable wormholes require the existence of exotic matter (matter that
violates weak or null energy conditions [WEC or NEC]). In this article, we
provide a class of exact solution for Einstein-Maxwell field equations
describing wormholes assuming the erstwhile cosmological term to be
space variable, viz., .
The source considered here not only a matter entirely but a sum of matters
i.e. anisotropic matter distribution, electromagnetic field and cosmological
constant whose effective parts obey all energy conditions out side the wormhole
throat. Here violation of energy conditions can be compensated by varying
cosmological constant. The important feature of this article is that one can
get wormhole structure, at least theoretically, comprising with physically
acceptable matters.Comment: Some changes have been mad
Coherent states for the hydrogen atom: discrete and continuous spectra
We construct the systems of generalised coherent states for the discrete and
continuous spectra of the hydrogen atom. These systems are expressed in
elementary functions and are invariant under the (discrete spectrum)
and (continuous spectrum) subgroups of the dynamical symmetry group
of the hydrogen atom. Both systems of coherent states are particular
cases of the kernel of integral operator which interwines irreducible
representations of the group.Comment: 15 pages, LATEX, minor sign corrections, to appear in J.Phys.
Water Dynamics at Protein Interfaces: Ultrafast Optical Kerr Effect Study
The behavior of water molecules surrounding a protein can have an important bearing on its structure and function. Consequently, a great deal of attention has been focused on changes in the relaxation dynamics of water when it is located at the protein surface. Here we use the ultrafast optical Kerr effect to study the H-bond structure and dynamics of aqueous solutions of proteins. Measurements are made for three proteins as a function of concentration. We find that the water dynamics in the first solvation layer of the proteins are slowed by up to a factor of 8 in comparison to those in bulk water. The most marked slowdown was observed for the most hydrophilic protein studied, bovine serum albumin, whereas the most hydrophobic protein, trypsin, had a slightly smaller effect. The terahertz Raman spectra of these protein solutions resemble those of pure water up to 5 wt % of protein, above which a new feature appears at 80 cm–1, which is assigned to a bending of the protein amide chain
Classical Euclidean wormhole solutions in Palatini cosmology
We study the classical Euclidean wormholes in the context of extended
theories of gravity. With no loss of generality, we use the dynamical
equivalence between gravity and scalar-tensor theories to
construct a point-like Lagrangian in the flat FRW space time. We first show the
dynamical equivalence between Palatini gravity and the
Brans-Dicke theory with self-interacting potential, and then show the dynamical
equivalence between the Brans-Dicke theory with self-interacting potential and
the minimally coupled O'Hanlon theory. We show the existence of new Euclidean
wormhole solutions for this O'Hanlon theory and, for an special case, find out
the corresponding form of having wormhole solution. For small
values of the Ricci scalar, this is in agreement with the
wormhole solution obtained for higher order gravity theory .Comment: 11 page
Particle density fluctuations
Event-by-event fluctuations in the multiplicities of charged particles and
photons at SPS energies are discussed. Fluctuations are studied by controlling
the centrality of the reaction and rapidity acceptance of the detectors.
Results are also presented on the event-by-event study of correlations between
the multiplicity of charged particles and photons to search for DCC-like
signals.Comment: Talk presented at Quark Matter 2002, Nantes, Franc
Search for DCC in 158A GeV Pb+Pb Collisions
A detailed analysis of the phase space distributions of charged particles and
photons have been carried out using two independent methods. The results
indicate the presence of nonstatistical fluctuations in localized regions of
phase space.Comment: Talk at the PANIC99 Conference, June 9-16, 199
Multiplicity Distributions and Charged-neutral Fluctuations
Results from the multiplicity distributions of inclusive photons and charged
particles, scaling of particle multiplicities, event-by-event multiplicity
fluctuations, and charged-neutral fluctuations in 158 GeV Pb+Pb
collisions are presented and discussed. A scaling of charged particle
multiplicity as and photons as have been observed, indicating violation of naive wounded nucleon model.
The analysis of localized charged-neutral fluctuation indicates a
model-independent demonstration of non-statistical fluctuations in both charged
particles and photons in limited azimuthal regions. However, no correlated
charged-neutral fluctuations are observed.Comment: Talk given at the International Symposium on Nuclear Physics
(ISNP-2000), Mumbai, India, 18-22 Dec 2000, Proceedings to be published in
Pramana, Journal of Physic
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