Paper: astro-ph/0505494
Date: Tue, 24 May 2005 20:00:12 GMT (48kb)

Title: The Limits of Quintessence

Authors: R.R. Caldwell, Eric V. Linder
Comments: 4 pages, 2 figures
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We present evidence that the simplest particle-physics scalar-field models of
dynamical dark energy can be separated into distinct behaviors based on the
acceleration or deceleration of the field as it evolves down its potential
towards a zero minimum. We show that these models occupy narrow regions in the
phase-plane of w and w', the dark energy equation-of-state and its
time-derivative in units of the Hubble time. Restricting an energy scale of the
dark energy microphysics limits how closely a scalar field can resemble a
cosmological constant. These results, indicating a desired measurement
resolution of order \sigma(w')\approx (1+w), define firm targets for
observational tests of the physics of dark energy.

\\ ( http://arXiv.org/abs/astro-ph/0505494 , 48kb)
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Paper: astro-ph/0505497
Date: Wed, 25 May 2005 14:14:13 GMT (52kb)

Title: Spherical Gravitational Collapse of Annihilating Dark Matter and the
Minimum Mass of CDM Black Holes

Authors: R. Ali Vanderveld and Ira Wasserman
\\
Spherical gravitational collapse of a cold gas of annihilating particles
involves a competition between the free-fall rate $\propto\sqrt{\rho}$ and the
(s-wave) annihilation rate $\propto\rho$. Thus, there is a critical density
$\rhoann$ above which annihilation proceeds faster than free fall.
Gravitational collapse of a cloud of (initial) mass $M$ to a black hole is only
possible if $3/32\pi G^3M^2\lesssim\rhoann$, or $M\gtrsim\Mann\equiv (3/32\pi
G^3\rhoann)^{1/2}$. For a particle mass $m$ and freeze-out temperature
$T_f=m/x_f$, the minimum black hole mass is $\Mann\approx 10^{10}\msun
\times(x_f\sqrt{g_\star}/100\omcdm g_{\star S}m({\rm Gev}))$, where $g_{\star
S}$ and $g_\star$ are degeneracy factors. The formation of a black hole of
initial mass $M_{BH}$ is accompanied by the annihilation of about $M_{ann}$
released in a burst lasting a time $\sim GM_{BH}$ that could reach a total
annihilation luminosity $\sim 10^{59} {\rm erg s^{-1}}$. The absence of
astronomical observations of such spectacular events suggests either: (i) the
branching ratio for CDM annihilation to $e^{+}e^{-}$ pairs or quarks $\lesssim
10^{-10}$, while the branching ratio to $\nu{\bar{\nu}}$ is $\lesssim 10^{-5}$;
or (ii) CDM is not made of annihilating particles, but may be in some
non-annihilating form, such as axions; or (iii) CDM black holes never form.

\\ ( http://arXiv.org/abs/astro-ph/0505497 , 52kb)

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Paper (*cross-listing*): hep-th/0505215
Date: Tue, 24 May 2005 11:52:12 GMT (19kb)

Title: Inhomogeneous Equation of State of the Universe: Phantom Era, Future
Singularity and Crossing the Phantom Barrier

Authors: Shin'ichi Nojiri and Sergei D. Odintsov
Comments: 13 pages
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The dark energy universe equation of state (EOS) with inhomogeneous,Hubble
parameter dependent term is considered. The motivation to introduce such a term
comes from time-dependent viscosity considerations and modifications of general
relativity. For several explicit examples of such EOS it is demonstrated how
the type of future singularity changes, how the phantom epoch emerges and how
crossing of phantom barrier occurs. Similar cosmological regimes are considered
for the universe with two interacting fluids and for universe with implicit
EOS. For instance, the crossing of phantom barrier is realized in easier way,
thanks to the presence of inhomogeneous term. The thermodynamical dark energy
model is presented where the universe entropy may be positive even at phantom
era as a result of crossing of w=-1 barrier.

\\ ( http://arXiv.org/abs/hep-th/0505215 , 19kb)

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Paper: astro-ph/0503265
replaced with revised version Wed, 25 May 2005 13:04:17 GMT (423kb)

Title: Final results of the EDELWEISS-I dark matter search with cryogenic
heat-and-ionization Ge detectors

Authors: V. Sanglard, A. Benoit, L. Berge, J. Blumer, A. Broniatowski, B.
Censier, L. Chabert, M. Chapellier, G. Chardin, P. Charvin, S. Collin, M. De
Jesus, H. Deschamps, P. Di Stefano, Y. Dolgorouky, D. Drain, L. Dumoulin, K.
Eitel, M. Fesquet, S. Fiorucci, J. Gascon, G. Gerbier, E. Gerlic, C.
Goldbach, M. Goyot, M. Gros, S. Herve, M. Horn, A. Juillard, M. Karolak, C.
Kikuchi, A. de Lesquen, M. Luca, J. Mallet, S. Marnieros, L. Mosca, X.-F.
Navick, G. Nollez, P. Pari, L. Schoeffel, M. Stern, L. Vagneron, V. Villar
Comments: 42 pages, 16 figures, submitted to Physical Review D, 1 figure and 2
references added, some little changes in the text

\\ ( http://arXiv.org/abs/astro-ph/0503265 , 423kb)

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Paper (*cross-listing*): gr-qc/0505031
replaced with revised version Wed, 25 May 2005 17:10:42 GMT (11kb)

Title: General covariance violation and the gravitational dark matter. I.
Scalar graviton

Authors: Yu. F. Pirogov
Comments: 9 pages; typos corrected
Report-no: IHEP 2005-15

\\ ( http://arXiv.org/abs/gr-qc/0505031 , 11kb)

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Paper (*cross-listing*): hep-th/0504052
replaced with revised version Wed, 25 May 2005 12:32:12 GMT (11kb)

Title: Gauss-Bonnet dark energy

Authors: Shin'ichi Nojiri, Sergei D. Odintsov, and Misao Sasaki
Comments: LaTeX file, 9 pages, some revision/errors corrected
Report-no: YITP-05-14

\\ ( http://arXiv.org/abs/hep-th/0504052 , 11kb)

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