40 research outputs found
Thermodynamics of phantom energy in the presence of a Reissner-Nordstrom black hole
In this paper, we study the validity of the generalized second law (GSL) in
phantom dominated universe in the presence of a Reissner-Nordstr\"{o}m (RN)
black hole. Our study is independent of the origin of the phantom like behavior
of the considered universe. We also discuss the GSL in the neighborhood of
transition from quintessence to phantom regime. We show that for a constant
equation of state parameter, the GSL may be satisfied provided that the
temperature is proportional to de Sitter temperature. It is shown that in
models with (only) a transition from quintessence to phantom regime the
generalized second law does not hold in the transition epoch. Next we show that
if the phantom energy has a chemical potential, then the GSL will hold if the
mass of black hole is above from a critical value.Comment: 5 pages, Accepted for publication in Astrophysics & Space Scienc
Interpreting the New Brookhaven g_mu - 2 Result
The latest g_mu - 2 measurement by Brookhaven confirms the earlier
measurement with twice the precision. However, interpretation of the result
requires specific assumptions regarding the errors in the hadronic light by
light (LbL) correction and in the hadronic vacuum polarization correction.
Under the assumption that the analysis on LbL correction of Knecht and Nyffeler
and the revised analysis of Hayakawa and Kinoshita are valid the new BNL result
implies a deviation between experiment and the standard model of 1.6 sigma -2.6
sigma depending on the estimate of the hadronic vacuum polarization correction.
We revisit the g_mu - 2 constraint for mSUGRA and its implications for the
direct detection of sparticles at colliders and for the search for
supersymmetric dark matter in view of the new evaluation.Comment: 15 pages, Latex including 3 figure
Prospects for e+e- physics at Frascati between the phi and the psi
We present a detailed study, done in the framework of the INFN 2006 Roadmap,
of the prospects for e+e- physics at the Frascati National Laboratories. The
physics case for an e+e- collider running at high luminosity at the phi
resonance energy and also reaching a maximum center of mass energy of 2.5 GeV
is discussed, together with the specific aspects of a very high luminosity
tau-charm factory. Subjects connected to Kaon decay physics are not discussed
here, being part of another INFN Roadmap working group. The significance of the
project and the impact on INFN are also discussed. All the documentation
related to the activities of the working group can be found in
http://www.roma1.infn.it/people/bini/roadmap.html.Comment: INFN Roadmap Report: 86 pages, 25 figures, 9 table