Automatised full one-loop renormalisation of the MSSM I: The Higgs sector, the issue of tan(beta) and gauge invariance

We give an extensive description of the renormalisation of the Higgs sector of the minimal supersymmetric model in SloopS. SloopS is an automatised code for the computation of one-loop processes in the MSSM. In this paper, the first in a series, we study in detail the non gauge invariance of some definitions of tan(beta). We rely on a general non-linear gauge fixing constraint to make the gauge parameter dependence of different schemes for tan(beta) at one-loop explicit. In so doing, we update, within these general gauges, an important Ward-Slavnov-Taylor identity on the mixing between the pseudo-scalar Higgs, A^0, and the Z^0. We then compare the tan(beta) scheme dependence of a few observables. We find that the best tan(beta) scheme is the one based on the decay A^0 -> tau^+ tau^- because of its gauge invariance, being unambiguously defined from a physical observable, and because it is numerically stable. The oft used DRbar scheme performs almost as well on the last count, but is usually defined from non-gauge invariant quantities in the Higgs sector. The use of the heavier scalar Higgs mass in lieu of tan(beta) though related to a physical parameter induces too large radiative corrections in many instances and is therefore not recommended.Comment: 34 pages, 1 figure, typos corrected, accepted for publication in Phys. Rev.

Relic density at one-loop with gauge boson pair production

We have computed the full one-loop corrections (electroweak as well as QCD) to processes contributing to the relic density of dark matter in the MSSM where the LSP is the lightest neutralino. We cover scenarios where the most important channels are those with gauge boson pair production. This includes the case of a bino with some wino admixture, a higgsino and a wino. In this paper we specialise to the case of light dark matter much below the TeV scale. The corrections can have a non-negligible impact on the predictions and should be taken into account in view of the present and forthcoming increasing precision on the relic density measurements. Our calculations are made with the help of \SloopS, an automatic tool for the calculation of one-loop processes in the MSSM. The renormalisation scheme dependence of the results as concerns \tgb is studied.Comment: 25 pages, 10 figures, Citations adde

Approximation on Nash sets with monomial singularities

This paper is devoted to the approximation of differentiable semialgebraic functions by Nash functions. Approximation by Nash functions is known for semialgebraic functions defined on an affine Nash manifold M, and here we extend it to functions defined on Nash subsets X of M whose singularities are monomial. To that end we discuss first "finiteness" and "weak normality" for such sets X. Namely, we prove that (i) X is the union of finitely many open subsets, each Nash diffeomorphic to a finite union of coordinate linear varieties of an affine space and (ii) every function on X which is Nash on every irreducible component of X extends to a Nash function on M. Then we can obtain approximation for semialgebraic functions and even for certain semialgebraic maps on Nash sets with monomial singularities. As a nice consequence we show that m-dimensional affine Nash manifolds with divisorial corners which are class k semialgebraically diffeomorphic, for k>m^2, are also Nash diffeomorphic.Comment: 39 page

Automatised full one-loop renormalisation of the MSSM II: The chargino-neutralino sector, the sfermion sector and some applications

An on-shell renormalisation programme for the chargino/neutralino and the sfermion sectors within the Minimal Supersymmetric Standard Model as implemented in a fully automated code, SloopS, for the calculation of one-loop processes at the colliders and in astrophysics, is presented. This is a sequel to our study in arXiv:0807.4668 [hep-ph] where an on-shell renormalisation of the Higgs (and the gauge/fermion) sector is performed. The issue of mixing is treated in a unified and coherent manner in all these sectors, in particular we give some new insight into the renormalisation of the mixing angle in the sfermion sector and like with the Higgs sector and the issue of tan(beta) we discuss different schemes. We also perform numerical comparisons between our code SloopS and different results found in the literature. In particular we consider loop corrections to the neutralino and sfermion masses, chargino pair production and stau pair production in e^{+}e^{-} colliders, as well as a few decays of the heavier chargino. For all these observables, we analyse the tan(beta) scheme dependence using different definitions of this parameter and comment on the impact of using different renormalisation of the mixing parameter in the sfermion sector.Comment: 41 pages, 14 figures, added reference

Spectral Spaces in o-minimal and other NIP theories

We study some model-theoretic notions in NIP by means of spectral topology. In the o-minimal setting we relate the o-minimal spectrum with other topological spaces such as the real spectrum and the space of infinitesimal types of Peterzil and Starchenko. In particular, we prove for definably compact groups that the space of closed points is homeomorphic to the space of infinitesimal types. We also prove that with the spectral topology the set of invariant types concentrated in a definably compact set is a normal spectral space whose closed points are the finitely satisfiable types. On the other hand, for arbitrary NIP structures we equip the set of invariant types with a new topology, called the {\em honest topology}. With this topology the set of invariant types is a normal spectral space whose closed points are the finitely satisfiable ones, and the natural retraction from invariant types onto finitely satisfiable types coincides with Simon's $F_M$ retraction

Loop-induced photon spectral lines from neutralino annihilation in the NMSSM

We have computed the loop-induced processes of neutralino annihilation into two photons and, for the first time, into a photon and a Z boson in the framework of the NMSSM. The photons produced from these radiative modes are monochromatic and possess a clear "smoking gun" experimental signature. This numerical analysis has been done with the help of the SloopS code, initially developed for automatic one-loop calculation in the MSSM. We have computed the rates for different benchmark points coming from SUGRA and GMSB soft SUSY breaking scenarios and compared them with the MSSM. We comment on how this signal can be enhanced, with respect to the MSSM, especially in the low mass region of the neutralino. We also discuss the possibility of this observable to constrain the NMSSM parameter space, taking into account the latest limits from the FERMI collaboration on these two modes.Comment: 18 pages, 3 figures. Minor clarifications added in the text. Typing mistakes and references corrected. Matches published versio

Searching for Dark Matter at the LHC with a Mono-Z

We investigate a mono-Z process as a potential dark matter search strategy at the LHC. In this channel a single Z boson recoils against missing transverse momentum, attributed to dark matter particles, $\chi$, which escape the detector. This search strategy is related, and complementary to, monojet and monophoton searches. For illustrative purposes we consider the process $q\bar{q} -> \chi\chi Z$ in a toy dark matter model, where the Z boson is emitted from either the initial state quarks, or from the internal propagator. Among the signatures of this process will be a pair of muons with high pT that reconstruct to the invariant mass of the Z, and large amounts of missing transverse energy. Being a purely electroweak signal, QCD and other Standard Model backgrounds are relatively easily removed with modest selection cuts. We compare the signal to Standard Model backgrounds and demonstrate that, even for conservative cuts, there exist regions of parameter space where the signal may be clearly visible above background in future LHC data, allowing either new discovery potential or the possibility of supplementing information about the dark sector beyond that available from other observable channels.Comment: 11 pages, 13 figure

First substantiated record of Raja asterias Delaroche, 1809 (Elasmobranchii: Rajiformes: Rajidae) in the Gulf of Cádiz, North-eastern Atlantic

The Mediterranean starry ray, Raja asterias, considered endemic in the Mediterranean, has recently been reported by other authors from Atlantic fisheries in southern Portugal and northern Morocco. There has been, however, no substantiated record of the species outside the Mediterranean. This fact and the easiness of confusion of R. asterias with other species have probably prevented those records from being taken into account in the recent catalogue of North Atlantic elasmobranchs species, in the assessment of the population status of this species, and in recent annotated global checklists of chondrichthyans. In our study, a specimen of R. asterias was collected from the Gulf of Cádiz and its species identity was assessed based on morphological and molecular methods. The presently reported finding constitutes a substantiated record of R. asterias from the Atlantic. Based on this record, previously reported catches of the Mediterranean starry ray in the Atlantic should be confirmed, and if so, these populations should be included in future assessments of this vulnerable species and in the description of its geographic distributionVersión del editor0,54

Measurement and Processing of Road Irregularity for Surface Generation and Tyre Dynamics Simulation in NVH Context

Nowadays, finite element tyre models are often used to perform vehicle NVH (noise, vibration, harshness) simulations. To account for the specific operating conditions, a road surface must be properly included in the model. This paper deals with a methodology to experimentally evaluate and process road irregularity measurements, so as to generate a road surface input. These surfaces are used to simulate the tyre/road interaction at the footprint, which is modelled as a contact surface in finite element tyre models. For this reason, a linear profile of the road surface is not suitable for these simulations and the whole surface must be considered. Starting from the measurements taken through a test equipment specifically designed to carry laser sensors and scan road profiles, the Power Spectral Density (PSD) of a specific track is estimated and then interpolated considering piecewise functions. Finally, a model to generate a road surface starting from the measured PSD is developed, discussed and validated