Article

# Branon radiative corrections to collider physics and precision observables

Physical review D: Particles and fields 11/2005; DOI: 10.1103/PhysRevD.73.035008

Source: arXiv

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**ABSTRACT:**We study the possibility of testing some generic properties of brane world scenarios at the LHC. In particular, we pay attention to Kaluza-Klein graviton and branon production. Both signals can be dominant depending on the value of the brane tension. We analyze the differences between these two signatures. Finally, we use recent data in the single photon channel from the ATLAS Collaboration to constrain the parameter space of both phenomenologies.Physical Review D 10/2013; 88(7). · 4.86 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**One possible explanation for the present observed acceleration of the Universe is the breakdown of homogeneity and isotropy due to the formation of non-linear structures. How inhomogeneities affect the averaged cosmological expansion rate and lead to late-time acceleration is generally considered to be due to some backreaction mechanism. General Relativity together with pressure-free matter have until recently been considered as the sole ingredients for averaged calculations. In this communication we focus our attention on more general scenarios, including imperfect fluids as well as alternative theories of gravity, and apply an averaging procedure to them in order to determine possible backreaction effects. For illustrative purposes, we present our results for dark energy models, quintessence and Brans-Dicke theories. We also provide a discussion about the limitations of frame choices in the averaging procedure.Journal of Cosmology and Astroparticle Physics 12/2013; 2014(05). · 5.88 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**In this work we address the issue of studying the conditions required to guarantee the Focusing Theorem for both null and timelike geodesic congruences by using the Raychaudhuri equation. In particular we study the case of Friedmann-Robertson-Walker as well as more general Bianchi Type I spacetimes. The fulfillment of the Focusing Theorem is mandatory in small scales since it accounts for the attractive character of gravity. However, the Focusing Theorem is not satisfied at cosmological scales due to the measured negative deceleration parameter. The study of the conditions needed for congruences convergence is not only relevant at the fundamental level but also to derive the viability conditions to be imposed on extended theories of gravity describing the different expansion regimes of the universe. We illustrate this idea for f(R) gravity theories.Journal of Cosmology and Astroparticle Physics 03/2014; 2014(03). · 5.88 Impact Factor

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