7 research outputs found
Supersymmetric new brane-world
The quantum-induced dilatonic brane world (New Brane World) is created by
brane CFT quantum effects (giving effective brane tension) in accordance with
AdS/CFT set-up which also defines surface term. Considering the bosonic sector
of 5d gauged supergravity with single scalar and taking the boundary action as
predicted by supersymmetry, the possibility to supersymmetrize dilatonic New
Brane World is discussed. It is demonstrated that for a number of
superpotentials the flat SUSY dilatonic brane-world (with dynamically induced
brane dilaton) or quantum-induced de Sitter dilatonic brane-world (not Anti-de
Sitter one) where SUSY is broken by the quantum effects occurs. The analysis of
graviton perturbations indicates that gravity is localized on such branes.Comment: LaTeX 16 pages, misprints are correcte
Mining Energy from a Black Hole by Strings
We discuss how cosmic strings can be used to mine energy from black holes. A
string attached to the black hole gives rise to an additional channel for the
energy release. It is demonstrated that when a string crosses the event
horizon, its transverse degrees of freedom are thermally excited and thermal
string perturbations propagate along the string to infinity. The internal
metric induced on the 2D worldsheet of the static string crossing the horizon
describes a 2D black hole. For this reason thermal radiation of string
excitations propagating along the string can be interpreted as Hawking
radiation of the 2D black hole. It is shown that the rate of energy emission
through the string channel is of the same order of magnitude as the bulk
radiation of the black hole. Thus, for N strings attached to the black hole the
efficiency of string channels is increased by factor N. We discuss restrictions
on N which exist because of the finite thickness of strings, the gravitational
backreaction and quantum fluctuations. Our conclusion is that the energy
emission rate by strings can be increased as compared to the standard emission
in the bulk by the factor 10^3 for GUT strings and up to the factor 10^{31} for
electroweak strings.Comment: 13 pages, no figures, final version to appear in Physical Revie
Rare Charm Decays in the Standard Model and Beyond
We perform a comprehensive study of a number of rare charm decays,
incorporating the first evaluation of the QCD corrections to the short distance
contributions, as well as examining the long range effects. For processes
mediated by the transitions, we show that sensitivity to
short distance physics exists in kinematic regions away from the vector meson
resonances that dominate the total rate. In particular, we find that
and are sensitive to non-universal
soft-breaking effects in the Minimal Supersymmetric Standard Model with
R-parity conservation. We separately study the sensitivity of these modes to
R-parity violating effects and derive new bounds on R-parity violating
couplings. We also obtain predictions for these decays within extensions of the
Standard Model, including extensions of the Higgs, gauge and fermion sectors,
as well as models of dynamical electroweak symmetry breaking.Comment: 45 pages, typos fixed, discussions adde
Quark Confinement in a Constituent Quark Model
On the level of an effective quark theory, we define confinement by the
absence of quark anti-quark thresholds in correlation functions. We then
propose a confining Nambu-Jona-Lasinio-type model. The confinement is
implemented in analogy to Anderson localization in condensed matter systems. We
study the model's phase structure as well as its behavior under extreme
conditions, i.e.\ high temperature and/or high density.Comment: 40 pages, 14 figures, complete uu-file avaiable on reques