19,759 research outputs found

    QCD contributions to the thermal history of the early Universe

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    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

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    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

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    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

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    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

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    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

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    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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