440 research outputs found
What can the SNO Neutral Current Rate teach us about the Solar Neutrino Anomaly
We investigate how the anticipated neutral current rate from will
sharpen our understanding of the solar neutrino anomaly. Quantitative analyses
are performed with representative values of this rate in the expected range of
. This would provide a signal for transition
into a state containing an active neutrino component. Assuming this state to be
purely active one can estimate both the neutrino flux and the
survival probability to a much higher precision than currently possible.
Finally the measured value of the rate will have profound implications for
the mass and mixing parameters of the solar neutrino oscillation solution.Comment: Brief discussion on the first NC result from SNO added; final version
to be published in the MPL
A review: Solar cell current scenario and future trends
In recent years solar cell technology has achieved tremendous growth as sustainable source of energy. In last few years photovoltaic industries have emerged with an annual growth of 40%.Solar cells are renewable pollution free source of electrical energy which can easily replace traditional fossil fuels. In this article we have reviewed the previous and current status of various generations of solar cells and discussed about their future trends and aspects. 
Three Generation Neutrino Oscillation Parameters after SNO
We examine the solar neutrino problem in the context of the realistic three
neutrino mixing scenario including the SNO charged current (CC) rate. The two
independent mass squared differences and are taken to be in the solar and atmospheric ranges
respectively. We incorporate the constraints on m as obtained
by the SuperKamiokande atmospheric neutrino data and determine the allowed
values of , and from a combined
analysis of solar and CHOOZ data. Our aim is to probe the changes in the values
of the mass and mixing parameters with the inclusion of the SNO data as well as
the changes in the two-generation parameter region obtained from the solar
neutrino analysis with the inclusion of the third generation. We find that the
inclusion of the SNO CC rate in the combined solar + CHOOZ analysis puts a more
restrictive bound on . Since the allowed values of
are constrained to very small values by the CHOOZ experiment there is no
qualitative change over the two generation allowed regions in the plane. The best-fit comes in the LMA region and
no allowed area is obtained in the SMA region at 3 level from combined
solar and CHOOZ analysis.Comment: One reference added. Version to apprear in PR
MSW mediated neutrino decay and the solar neutrino problem
We investigate the solar neutrino problem assuming simultaneous presence of
MSW transitions in the sun and neutrino decay on the way from sun to earth. We
do a global -analysis of the data on total rates in Cl, Ga and
Superkamiokande (SK) experiments and the SK day-night spectrum data and
determine the changes in the allowed region in the \dm - \tan^2\theta plane
in presence of decay. We also discuss the implications for unstable neutrinos
in the SNO experiment.Comment: Final version to appear in Phys. Rev.
Testing the solar LMA region with KamLAND data
We investigate the potential of 3 kiloTon-years(kTy) of KamLAND data to
further constrain the and values compared to those
presently allowed by existing KamLAND and global solar data. We study the
extent, dependence and characteristics of this sensitivity in and around the
two parts of the LMA region that are currently allowed. Our analysis with 3 kTy
simulated spectra shows that KamLAND spectrum data by itself can constrain
with high precision. Combining the spectrum with global solar data
further tightens the constraints on allowed values of and
. We also study the effects of future neutral current data with a
total error of 7% from the Sudbury Neutrino Observatory. We find that these
future measurements offer the potential of considerable precision in
determining the oscillation parameters (specially the mass parameter).Comment: 16 pages, to appear in J Phys.
Flavor Symmetry L_mu - L_tau and quasi-degenerate Neutrinos
Current data implies three simple forms of the neutrino mass matrix, each
corresponding to the conservation of a non-standard lepton charge. While models
based on L_e and L_e - L_mu - L_tau are well-known, little attention has been
paid to L_mu - L_tau. A low energy mass matrix conserving L_mu - L_tau implies
quasi-degenerate light neutrinos. Moreover, it is mu-tau symmetric and
therefore (in contrast to L_e and L_e - L_mu - L_tau) automatically predicts
maximal atmospheric neutrino mixing and zero U_{e3}. A see-saw model based on
L_mu - L_tau is investigated and testable predictions for the neutrino mixing
observables are given. Renormalization group running below and in between the
see-saw scales is taken into account in our analysis, both numerically and
analytically.Comment: 15 pages, 2 figures. Prepared for 5th International Conference on
Nonaccelerator New Physics (NANP 05), Dubna, Russia, 20-25 Jun 200
Dynamics of cubic-tetragonal phase transition in KNbO perovskite
The low-energy part of the vibration spectrum in KNbO was studied by cold
neutron inelastic scattering in the cubic phase. In addition to acoustic
phonons, we observe strong diffuse scattering, which consists of two
components. The first one is quasi-static and has a temperature-independent
intensity. The second component appears as quasi-elastic scattering in the
neutron spectrum indicating a dynamic origin. From analysis of the inelastic
data we conclude that the quasi-elastic component and the acoustic phonon are
mutually coupled. The susceptibility associated with the quasi-elastic
component grows as the temperature approaches T
Atomic-scale Electronic Structure of the Cuprate Pair Density Wave State Coexisting with Superconductivity
The defining characteristic of hole-doped cuprates is -wave high
temperature superconductivity. However, intense theoretical interest is now
focused on whether a pair density wave state (PDW) could coexist with cuprate
superconductivity (D. F. Agterberg et al., Annual Review of Condensed Matter
Physics 11, 231 (2020)). Here, we use a strong-coupling mean-field theory of
cuprates, to model the atomic-scale electronic structure of an eight-unit-cell
periodic, -symmetry form factor, pair density wave (PDW) state coexisting
with -wave superconductivity (DSC). From this PDW+DSC model, the
atomically-resolved density of Bogoliubov quasiparticle states N(r,E) is
predicted at the terminal BiO surface of BiSrCaCuO and compared
with high-precision electronic visualization experiments using spectroscopic
imaging STM. The PDW+DSC model predictions include the intra-unit-cell
structure and periodic modulations of N(r,E), the modulations of the coherence
peak energy (r), and the characteristics of Bogoliubov quasiparticle
interference in scattering-wavevector space (q-space). Consistency between all
these predictions and the corresponding experiments indicates that lightly
hole-doped BiSrCaCuO does contain a PDW+DSC state. Moreover, in
the model the PDW+DSC state becomes unstable to a pure DSC state at a critical
hole density p*, with empirically equivalent phenomena occurring in the
experiments. All these results are consistent with a picture in which the
cuprate translational symmetry breaking state is a PDW, the observed charge
modulations are its consequence, the antinodal pseudogap is that of the PDW
state, and the cuprate critical point at p* ~ 19% occurs due to disappearance
of this PDW
- …