119202891
Nonlinear dynamics of 3D massive gravity
We explore the nonlinear classical dynamics of the three-dimensional theory of “New Massive Gravity” proposed by Bergshoeff, Hohm and Townsend. We find that the theory passes remarkably highly nontrivial consistency checks at the nonlinear level. In particular, we show that: (1) In the decoupling limit of the theory, the interactions of the helicity-0 mode are described by a single cubic term — the so-called cubic Galileon — previously found in the context of the DGP model and in certain 4D massive gravities. (2) The conformal mode of the metric coincides with the helicity-0 mode in the decoupling limit. Away from this limit the nonlinear dynamics of the former is described by a certain generalization of Galileon interactions, which like the Galileons themselves have a well-posed Cauchy problem. (3) We give a non-perturbative argument based on the presence of additional symmetries that the full theory does not lead to any extra degrees of freedom, suggesting that a 3D analog of the 4D Boulware-Deser ghost is not present in this theory. Last but not least, we generalize “New Massive Gravity” and construct a class of 3D cubic order massive models that retain the above properties.
14441164
Capture of Inelastic Dark Matter in the Sun
We consider the capture of dark matter in the Sun by inelastic scattering against nuclei as in the inelastic dark matter scenario. We show that, assuming a WIMP-nucleon cross-section of σn = 10−40 cm2 the resulting capture rate and density are sufficiently high so that current bounds on the muon neutrino flux from the Sun rule out any appreciable annihilation branching ratio of WIMPs into W+W−, Z0Z0, τ+τ−, t and neutrinos. Slightly weaker bounds are also available for annihilations into b and c. Annihilations into lighter particles that may produce neutrinos, such as μ+μ−, pions and kaons are unconstrained since those stop in the Sun before decaying. Interestingly enough, this is consistent with some recent proposals motivated by the PAMELA results for the annihilation of WIMPs into light bosons which subsequently decay predominantly into light leptons and pions.
123311038
A fifth force and the mediation of supersymmetry breaking
In this talk I will discuss a new mechanism for the mediation of supersymmetry breaking [1]. It relies on the existence of a fifth force, or what is more often refer to as a Z′ gauge‐boson. The existence of supersymmetry and an extra gauge‐boson is well motivated by the type of high‐energy theories (GUT models and string constructions) considered in the literature. The fact that neither has yet been seen is a possible hint that the two are linked and the present work is an attempt at exploring this connection.
125375882
A REVIEW OF SPIN DETERMINATION AT THE LHC
We review the prospects of direct spin determination of new particles which may be discovered at the LHC. We discuss the general framework and the different channels which contain spin information. The experimental challenges associated with such measurements are briefly discussed and the most urgent unresolved problems are emphasized.
119203743
RECAST — extending the impact of existing analyses
Searches for new physics by experimental collaborations represent a significant investment in time and resources. Often these searches are sensitive to a broader class of models than they were originally designed to test. We aim to extend the impact of existing searches through a technique we call recasting. A framework designed to facilitate the usage of this technique, called RECAST, is presented. We illustrate the issues and subtleties involved through several examples, including new results obtained from the reanalysis of archived LEP data. Website:www.recast.it
16835697
Anomalies in Fermionic UV Completions of Little Higgs Models
We consider fermionic UV completions of little Higgs models and their associated T-parity-violating anomalous vertices. In particular, we investigate strategies to avoid such parity-violating anomalies. We show that it is unlikely a QCD-like UV completion could be used to implement a model with anomaly-free global symmetry groups. This is because the vacuum state is unlikely to achieve the necessary alignment. However, we will see that certain multi-link moose models, although anomalous, possess a modified form of T-parity that leads to a stable particle. Finally, we briefly discuss a discriminant for detecting anomalous decays at colliders.
121839880
The influence of the nuclear medium on K+ total cross sections
Abstract The study of the K + total cross sections on a wide range of nuclei has revealed important modifications of the free-space K + -nucleon interaction when the nucleon is embedded in a nucleus. Data indicating such an effect were first obtained in a comparison of the total cross sections on carbon and deuterium. In this letter we report new measurements on 6 Li, silicon, and calcium, and demonstrate that the previously reported modifications occur quite generally.