5,517 research outputs found
One pion events by atmospheric neutrinos: A three flavor analysis
We study the one-pion events produced via neutral current (NC) and charged
current (CC) interactions by the atmospheric neutrinos. We analyze the ratios
of these events in the framework of oscillations between three neutrino
flavors. The ratios of the CC events induced by to that of the NC
events and a similar ratio defined with help us in distinguishing the
different regions of the neutrino parameter space.Comment: 14 pages, 4 figures (separate postscript files
Higgs Rapidity Distribution in Annihilation at Threshold in NLO QCD
We present the rapidity distribution of the Higgs boson produced through
bottom quark annihilation at third order in QCD using the threshold
approximation. We provide a framework, based on the factorization properties of
the QCD amplitudes along with Sudakov resummation and the renormalization group
invariance, that allows one to perform the computation of the threshold
corrections in a consistent, systematic and accurate way. The recent results on
threshold NLO correction in QCD for the Drell-Yan production and on three
loop QCD correction to Higgs form factor with bottom anti-bottom quark are used
to achieve this task. We also demonstrate the numerical impact of these
corrections at the LHC.Comment: 37 pages, 10 figure
Effect of Hypocaloric Stress on Body and Tissue Composition of Rats K
Rats fed ad libitum, a ration comprising fresh foods (F ration) for 10 days, were switched over to another ration consisting of processed foods (P ration) for a similar period. Thereafter, the animals were subjected to a 50 per cent diet restriction for a period of 10 days and rehabilitated either on F ration or P ration for an equal period. The results showed a decline in growth rate, food consumption and food efficiency ratio in the group fed ad libitum on P ration compared to that on F ration. Fifty per cent diet, restriction induced loss of body weight due to depletion of body fat. A fall in the gross weight of liver,kidney and epididymal fat pad along with a reduction in the contentsof lipid in liver and fat pad were also observed. Refeeding ofdiet-restricted rats induced hyperphagia and super-normal weight gainwith both rations. The data on liver triglycerides appeared to show anage-related rise which could be controlled by diet restriction to someextent. Feeding of P ration tended to predisperse to higher adiposetissue cholesterol attributable to higher fat content of this ration
Phenomenology of Neutrino Oscillations
The phenomenology of solar, atmospheric, supernova and laboratory neutrino
oscillations is described. Analytical formulae for matter effects are reviewed.
The results from oscillations are confronted with neutrinoless double beta
decay.Comment: 11 pages, 2 figures, latex, Plenary talk given at Workshop in High
Energy Particle Physics-6, Chennai, Indi
Analytical solutions of bound timelike geodesic orbits in Kerr spacetime
We derive the analytical solutions of the bound timelike geodesic orbits in
Kerr spacetime. The analytical solutions are expressed in terms of the elliptic
integrals using Mino time as the independent variable. Mino time
decouples the radial and polar motion of a particle and hence leads to forms
more useful to estimate three fundamental frequencies, radial, polar and
azimuthal motion, for the bound timelike geodesics in Kerr spacetime. This
paper gives the first derivation of the analytical expressions of the
fundamental frequencies. This paper also gives the first derivation of the
analytical expressions of all coordinates for the bound timelike geodesics
using Mino time. These analytical expressions should be useful not only to
investigate physical properties of Kerr geodesics but more importantly to
applications related to the estimation of gravitational waves from the extreme
mass ratio inspirals.Comment: A typo in the first expression in equation 21 was fixe
An ansatz for spacetimes of zero gravitational mass : global monopoles and textures
We propose a geometric ansatz, a restriction on Euclidean / Minkowski
distance in the embedding space being propotional to distance in the embedded
space, to generate spacetimes with vanishing gravitational mass (). It turns out that these spacetimes can represent
global monopoles and textures. Thus the ansatz is a prescription to generate
zero mass spacetimes that could describe topological defects, global monopoles
and textures.Comment: 9 pages, LaTeX versio
Dynamics of a Driven Single Flux Line in Superconductors
We study the low temperature dynamics of a single flux line in a bulk type-II
superconductor, driven by a surface current, both near and above the onset of
an instability which sets in at a critical driving. We found that above the
critical driving, the velocity profile of the flux line develops a
discontinuity.Comment: 10 pages with 4 figures, REVTE
Multi-Temperature Blackbody Spectra of Thin Accretion Disks With and Without a Zero-Torque Inner Boundary Condition
The standard spectral model for analyzing the soft component of thermal
emission from a thin accretion disk around a black hole is the
multi-temperature blackbody (MTB) model. The widely used implementation of this
model, which is known as ``diskbb,'' assumes nonzero torque at the inner edge
of the accretion disk. This assumption is contrary to the classic and current
literature on thin-disk accretion, which advocates the use of a zero-torque
boundary condition. Consequently, we have written code for a zero-torque model,
``ezdiskbb,'' which we compare to the nonzero-torque model diskbb by fitting
RXTE spectra of three well-known black hole binaries: 4U 1543-47, XTE
J1550-564, and GRO J1655-40. The chief difference we find is that the
zero-torque model gives a value for the inner disk radius that is about 2.2
times smaller than the value given by diskbb. This result has important
implications, especially for the determination of black-hole angular momentum
and mass accretion rate.Comment: 27 pages, 9 figures, submitted to Ap
Hysteretic dynamics of domain walls at finite temperatures
Theory of domain wall motion in a random medium is extended to the case when
the driving field is below the zero-temperature depinning threshold and the
creep of the domain wall is induced by thermal fluctuations. Subject to an ac
drive, the domain wall starts to move when the driving force exceeds an
effective threshold which is temperature and frequency-dependent. Similarly to
the case of zero-temperature, the hysteresis loop displays three dynamical
phase transitions at increasing ac field amplitude . The phase diagram in
the 3-d space of temperature, driving force amplitude and frequency is
investigated.Comment: 4 pages, 2 figure
- …