19,759 research outputs found
QCD contributions to the thermal history of the early Universe
We discuss the deviations from the ideal relativistic thermal bath. These
deviations are dominated from quantum chromodynamic (QCD) corrections in the
most part of the parameter space of the Standard Model (SM) and the Minimal
Supersymmetric Standard Model (MSSM). These effects are relevant for
astrophysical precision measurements and dynamics of scalar tensor theories
(SST).Comment: To appear in the AIP proceedings of "Quark Confinement and Hadron
Spectrum IX" (QCHSIX), Madrid 30th August-3rd September 2010. 3 page
Whitepaper on Super-weakly Interacting Massive Particles for Snowmass 2013
Super-weakly interacting massive particles produced in the late decays of
weakly interacting massive particles (WIMPs) are generic in large regions of
supersymmetric parameter space and other frameworks for physics beyond the
standard model. If their masses are similar to that of the decaying WIMP, then
they could naturally account for all of the cosmological dark matter abundance.
Their astrophysical consequences and collider signatures are distinct and
different from WIMP candidates. In particular, they could modify Big Bang
Nucleosynthesis, distort the Cosmic Microwave Background, reduce galactic
substructure and lower central densities of low-mass galaxies.Comment: 4 pages, 2 figures, white paper for Snowmass 201
QCD Effects in Cosmology
The cosmological evolution in the radiation dominated regimen is usually
computed by assuming an ideal relativistic thermal bath. In this note, we
discuss the deviation from the non-interaction assumption. In either the
standard model (SM) and the minimal supersymmetric standard model (MSSM), the
main contribution comes from the strong interaction. An understanding of these
effects are important for precision measurements and for the evolution of
scalar modes, where the commented corrections constitute the main source of the
dynamics.Comment: 4 pages, 2 figures. Contributed to CIPANP 2009: Tenth Conference on
the Intersections of Particle and Nuclear Physics, May 26-31, 2009, San
Diego, Californi
Extended Reissner-Nordstr\"om solutions sourced by dynamical torsion
We find a new exact vacuum solution in the framework of the Poincar\'e Gauge
field theory with massive torsion. In this model, torsion operates as an
independent field and introduces corrections to the vacuum structure present in
General Relativity. The new static and spherically symmetric configuration
shows a Reissner-Nordstr\"om-like geometry characterized by a spin charge. It
extends the known massless torsion solution to the massive case. The
corresponding Reissner-Nordstr\"om-de Sitter solution is also compatible with a
cosmological constant and additional U(1) gauge fields.Comment: 12 pages, 0 figures, minor changes, references adde
New torsion black hole solutions in Poincar\'e gauge theory
We derive a new exact static and spherically symmetric vacuum solution in the
framework of the Poincar\'e gauge field theory with dynamical massless torsion.
This theory is built in such a form that allows to recover General Relativity
when the first Bianchi identity of the model is fulfilled by the total
curvature. The solution shows a Reissner-Nordstr\"om type geometry with a
Coulomb-like curvature provided by the torsion field. It is also shown the
existence of a generalized Reissner-Nordstr\"om-de Sitter solution when
additional electromagnetic fields and/or a cosmological constant are coupled to
gravity.Comment: 14 pages, 0 figures, minor changes, references adde
Einstein-Yang-Mills-Lorentz black holes
Different black hole solutions of the coupled Einstein-Yang-Mills equations
have been well known for a long time. They have attracted much attention from
mathematicians and physicists since their discovery. In this work, we analyze
black holes associated with the gauge Lorentz group. In particular, we study
solutions which identify the gauge connection with the spin connection. This
ansatz allows one to find exact solutions to the complete system of equations.
By using this procedure, we show the equivalence between the Yang-Mills-Lorentz
model in curved space-time and a particular set of extended gravitational
theories.Comment: 10 pages, 0 figures, minor changes, references added. It matches the
version published in Eur. Phys. J.
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