7,838 research outputs found
Shell model and deformed shell model spectroscopy of Ga
In the present work we have reported comprehensive analysis of recently
available experimental data [H.M. David et al., Phys. Lett. B {\bf 726}, 665
(2013)] for high-spin states up to with in the odd-odd
nucleus Ga using shell model calculations within the full
model space and deformed shell model based on Hartee-Fock
intrinsic states in the same space. The calculations have been performed using
jj44b effective interaction developed recently by B.A. Brown and A.F. Lisetskiy
for this model space. The results obtained with the two models are similar and
they are in reasonable agreement with experimental data. In addition to the
and energy bands, band crossings and electromagnetic transition
probabilities, we have also calculated the pairing energy in shell model and
all these compare well with the available theoretical results.Comment: 9 pages, 4 figure
UHE neutrino damping in a thermal gas of relic neutrinos
We present a calculation of the damping of an ultra-energetic (UHE) cosmic
neutrino travelling through the thermal gas of relic neutrinos, using the
formalism of finite-temperature field theory. From the self-energy diagram due
to Z exchange, we obtain the annihilation cross section for an UHE neutrino
interacting with an antineutrino from the background. This method allows us to
derive the full expressions for the UHE neutrino transmission probability,
taking into account the momentum of relic neutrinos. We compare our results
with the approximations in use in the literature. We discuss the effect of
thermal motion on the shape of the absorption dips for different UHE neutrino
fluxes as well as in the context of relic neutrino clustering. We find that for
ratios of the neutrino mass to the relic background temperature or
smaller, the thermal broadening of the absorption lines could significantly
affect the determination of the neutrino mass and of the characteristics of the
population of UHE sources.Comment: 18 pages, 6 figures. Typos corrected. More accurate treatment of the
interaction with relic neutrino clusters. Accepted for publication in
Astroparticle Physic
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