6,378 research outputs found
Testing the Dipole Modulation Model in CMBR
The hemispherical power asymmetry, observed in the CMBR data, has generally
been interpreted in terms of the dipole modulation model for the temperature
fluctuations. Here we point out that this model leads to several predictions,
which can be directly tested in the current data. We suggest tests of the
hemispherical power asymmetry both in real and multipole space. We find a
significant signal of the dipole modulation model in WMAP and PLANCK data with
our tests. The dipole amplitude and direction also agrees, within errors, with
earlier results based on hemispherical analysis in multipole space. We also
find evidence that the effective dipole modulation amplitude increases with the
multipole l in the range l=2-64.Comment: 12 pages, 3 figures, major change
Noncommutative Geometry and the Primordial Dipolar Imaginary Power Spectrum
We argue that an anisotropic dipolar imaginary primordial power spectrum is
possible within the framework of noncommutative space-times. We show that such
a spectrum provides a good description of the observed dipole modulation in
CMBR data. We extract the corresponding power spectrum from data. The dipole
modulation is related to the observed hemispherical anisotropy in CMBR data,
which might represent the first signature of quantum gravity.Comment: 11 pages 1 figur
Exploring effective interactions through transition charge density study of nuclei
Transition charge density (TCD) for excitation have been
calculated for nuclei within microscopic variational
framework employing and valence
space. The calculated TCDs for different monopole variants of Kuo interaction
are compared with available experimental results. Other systematics like
reduced transition probabilities B(E2) and static quadrupole moments Q(2) are
also presented. It is observed that the transition density study acts as a
sensitive probe for discriminating the response of different parts of effective
interactions.Comment: 11 pages, 2 figures. Pramana - Journal of Physics (accepted, in
press
Relating the inhomogeneous power spectrum to the CMB hemispherical anisotropy
We relate the observed hemispherical anisotropy in the cosmic microwave
radiation data to an inhomogeneous power spectrum model. The hemispherical
anisotropy can be parameterized in terms of the dipole modulation model. This
model leads to correlations between spherical harmonic coefficients
corresponding to multipoles, l and l+1. We extract the dependence of the
dipole modulation amplitude, A, by making a fit to the WMAP and PLANCK CMBR
data. We propose an inhomogeneous power spectrum model and show that it also
leads to correlations between multipoles, l and l+1. The model parameters are
determined by making a fit to the data. The spectral index of the inhomogeneous
power spectrum is found to be consistent with zero.Comment: 13 pages, 2 figures, minor revision
Testing isotropy of cosmos with WMAP and PLANCK data
In recent years, there have been a large number of studies which support
violation of statistical isotropy. Meanwhile, there are some studies which also
found inconsistency. We use the power tensor method defined earlier in the
literature to study the new CMBR data. The orientation of these three
orthogonal vectors, as well as the power associated with each vector, contains
information about possible violation of statistical isotropy. This information
is encoded in two entropy measures, the power-entropy and alignment- entropy.
We apply this method to WMAP 9-year and PLANCK data. Here, we also revisit the
statistics to test high-l anomaly reported in our earlier paper and find that
the high degree of isotropy seen in earlier WMAP 5-year data is absent in the
revised WMAP 9-year data.Comment: 7 Pages, 0 Figures, 4 Tables; Published in 2015; Accepted version
added to arXiv no
Cosmological Power Spectrum in Non-commutative Space-time
We propose a generalized star product which deviates from the standard
product when the fields at evaluated at different space-time points. This
produces no changes in the standard Lagrangian density in non-commutative
space-time but produces a change in the cosmological power spectrum. We show
that the generalized star product leads to physically consistent results and
can fit the observed data on hemispherical anisotropy in the cosmic microwave
background radiation.Comment: 5 pages, no figures, major change
Deformation effects and neutrinoless positron decay of Ru, Pd, Cd, Xe, Ba and Dy isotopes within Majorona neutrino mass mechanism
The and
modes of Ru, Pd, Cd, Xe, Ba and
Dy isotopes are studied in the Projected Hartree-Fock-Bogoliubov
framework for the transition. The reliability of the intrinsic
wave functions required to study these decay modes has been established in our
earlier works by obtaining an overall agreement between the theoretically
calculated spectroscopic properties, namely yrast spectra, reduced
: transition probabilities, quadrupole moments
and gyromagnetic factors and the available experimental
data in the parent and daugther even-even nuclei. In the present work, the
required nuclear transition matrix elements are calculated in the Majorana
neutrino mass mechanism using the same set of intrinsic wave functions as used
to study the two neutrino positron double- decay modes. Limits on
effective light neutrino mass are extracted from the observed limits on half-lives
of and
modes. We also investigate the effect of
quadrupolar correlations vis-a-vis deformation on NTMEs required to study the
and modes.Comment: 12 Pages, 3 figur
Influence of the hexadecapole deformation on the two neutrino double-\be ta decay
The two neutrino double beta decay of Zr, Mo, Ru, Pd, Te and
Nd nuclei for the transition is studied in the PHFB
model in conjunction with the pairing plus quadrupole-quadrupole plus
hexadecapole-hexadecapole effective two-body interaction and the effect of the
latter is investigated on the calculation of nuclear transition matrix elements
. The reliability of the intrinsic wave functions of parent and
daughter nuclei involved in the decay of above
mentioned nuclei is established by obtaining an overall agreement between a
number of theoretically calculated spectroscopic properties, namely the yrast
spectra, reduced : transition probabilities, static
quadrupole moments and -factors and the available
experimental data. The effect of deformation on is also investigated
to inveterate its inverse relation with nuclear deformation.Comment: 12 page
Spin-tensor decomposition of nuclear transition matrix elements for neutrinoless double- decay of Ge and Se nuclei within PHFB approach
Employing the PHFB model, nuclear transition matrix elements for the neutrinoless double- decay of Ge and
Se isotopes are calculated within mechanisms involving light as well as
heavy Majorana neutrinos, and classical Majorons by considering the spin-tensor
decomposition of realistic KUO and empirical JUN45 effective two-body
interaction. It is noticed that the effects due to the SRC on NTMEs and due to the exchange of light and
heavy Majorana neutrinos, respectively, is maximally incorporated by the
central part of the effective two-body interaction, which varies by a small
amount with the inclusion of spin-orbit and tensor components. The maximum
uncertainty in the average NTMEs and
turns out to be about 10\% and 37\%, respectively
Uncertainties in nuclear transition matrix elements for and modes of neutrinoless positron double- decay within PHFB model
Uncertainties in the nuclear transition matrix elements and
of the double-positron emission and
electron-positron conversion modes due to the
exchange of light and heavy Majorana neutrinos, respectively, are calculated
for Ru, Pd, Cd, Xe, Ba and Dy
isotopes by employing the PHFB model with four different parameterization of
the pairing plus multipolar two-body interactions and three different
parameterizations of the Jastrow short range correlations. In all cases but for
Ba, the uncertainties are smaller than 14% for light Majorana neutrino
exchange and 35% for the exchange of a heavy Majorana neutrino
- …