8,531 research outputs found
Transient photon production in a QGP
We discuss the shortcomings of a formula that has been used in the literature
to compute the number of photons emitted by a hot or dense system during a
finite time, and show that the transient effects it predicts for the photon
rate are unphysical.Comment: 4 pages, to appear in the proceedings of Hadron Physics - RANP 2004,
Angra dos Reis, Brazi
Interactions in Quasicrystals
Although the effects of interactions in solid state systems still remains a
widely open subject, some limiting cases such as the three dimensional Fermi
liquid or the one-dimensional Luttinger liquid are by now well understood when
one is dealing with interacting electrons in {\it periodic} crystalline
structures. This problem is much more fascinating when periodicity is lacking
as it is the case in {\it quasicrystalline} structures. Here, we discuss the
influence of the interactions in quasicrystals and show, on a controlled
one-dimensional model, that they lead to anomalous transport properties,
intermediate between those of an interacting electron gas in a periodic and in
a disordered potential.Comment: Proceedings of the Many Body X conference (Seattle, Sept. 99); 9
pages; uses epsfi
Astrophysical Implication of Low E(2^+_1) in Neutron-rich Sn Isotopes
The observation and prediction of unusually depressed first excited 2^+_1
states in even-A neutron - rich isotopes of semi-magic Sn above 132Sn provide
motivations for reviewing the problems related to the nuclear astrophysics in
general. In the present work, the beta-decay rates of the exotic even Sn
isotopes (134,136Sn) above the 132Sn core have been calculated as a function of
temperature (T). In order to get the necessary ft values, B(GT) values
corresponding to allowed Gamow Teller (GT-) beta-decay have been theoretically
calculated using shell model. The total decay rate shows decrease with
increasing temperature as the ground state population is depleted and
population of excited states with slower decay rates increases. The abundance
at each Z value is inversely proportional to the decay constant of the waiting
point nucleus for that particular Z. So the increase in half-life of isotopes
of Sn, like 136Sn, might have substantial impact on the r-process
nucleosynthesis.Comment: 4th International Workshop on Nuclear Fission and Fission Product
Spectroscopy, CEA Cadarache, May 13 - 16, 2009, 4 pages, 2 figure
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