118589050
Avoiding Death by Vacuum
The two-Higgs doublet model (2HDM) can have two electroweak breaking, CP-conserving, minima. The possibility arises that the minimum which corresponds to the known elementary particle spectrum is metastable, a possibility we call the panic vacuum. We present analytical bounds on the parameters of the softly broken Peccei-Quinn 2HDM which are necessary and sufficient conditions to avoid this possibility. We also show that, for this particular model, the current LHC data already tell us that we are necessarily in the global minimum of the theory, regardless of any cosmological considerations about the lifetime of the false vacua.
119436002
Lepton flavor violating processes at the International Linear Collider
We study the effects of dimension-six effective operators on the flavor violating production and decay of leptons at the International Linear Collider. Analytic expressions for the cross sections, decay widths, and asymmetries of all flavor changing processes will be presented, as well as an analysis of the feasibility of their observation at the ILC.
18543360
Tree-Level Vacuum Stability in Multi Higgs Models
In the most general model with two Higgs doublets, if a minimum that preserves the $U(1)_{em}$ symmetry exists, then charge breaking (CB) minima cannot occur. The depth of the potential at a stationary point that breaks CB or CP, relative to the $U(1)_{em}$ preserving minimum, is proportional to the squared mass of the charged or pseudoscalar Higgs, respectively.
117960699
The CP-conserving 2HDM after the 8 TeV run
We confront the most common CP-conserving 2HDM with the LHC data analysed so far while taking into account all previously available experimental data. A special allowed corner of the parameter space is analysed - the so-called wrong-sign scenario where the Higgs coupling to down-type quarks changes sign relative to the Standard Model while the coupling to the massive vector bosons does not.
118913042
Lepton Flavour Violation at the ILC
We explore the possibility of detecting lepton flavour violation, now a well established experimental fact, at the International Linear Collider. Using a model independent approach we conclude that, given all experimental constraints available, there is still room to detect lepton flavour violation at the ILC.
119493491
One-loop stau masses in the effective potential approach
We calculate the one-loop contributions to the tau slepton masses in the Minimal Supersymmetric Standard Model in the effective potential approach. For the majority of parameter space under study, those corrections are shown to elevate the value of the lightest stau mass.
88503448
Towards a fully consistent parameterization of modified gravity
There is a distinct possibility that current and future cosmological data can be used to constrain Einstein's theory of gravity on the very largest scales. To be able to do this in a model-independent way, it makes sense to work with a general parameterization of modified gravity. Such an approach would be analogous to the Parameterized Post-Newtonian (PPN) approach which is used on the scale of the Solar System. A few such parameterizations have been proposed and preliminary constraints have been obtained. We show that the majority of such parameterizations are only exactly applicable in the quasistatic regime. On larger scales they fail to encapsulate the full behaviour of typical models currently under consideration. We suggest that it may be possible to capture the additions to the `Parameterized Post-Friedmann' (PPF) formalism by treating them akin to fluid perturbations.
118844551
An expanding locally anisotropic (ELA) metric describing matter in an expanding universe
Abstract It is suggested an expanding locally anisotropic metric (ELA) ansatz describing matter in a flat expanding universe which interpolates between the Schwarzschild (SC) metric near point-like central bodies of mass M and the Robertson–Walker (RW) metric for large radial coordinate: d s 2 = Z c 2 d t 2 − 1 Z ( d r 1 − H r 1 c Z α 2 + 1 2 c d t ) 2 − r 1 2 d Ω , where Z = 1 − U SC with U SC = 2 G M / ( c 2 r 1 ) , G is the Newton constant, c is the speed of light, H = H ( t ) = a ˙ / a is the time-dependent Hubble rate, d Ω = d θ 2 + sin 2 θ d φ 2 is the solid angle element, a is the universe scale factor and we are employing the coordinates r 1 = a r , being r the radial coordinate for which the RW metric is diagonal. For constant exponent α = α 0 = 0 it is retrieved the isotropic McVittie (McV) metric and for α = α 0 = 1 it is retrieved the locally anisotropic Cosmological-Schwarzschild (SCS) metric, both already discussed in the literature. However it is shown that only for constant exponent α = α 0 > 1 exists an event horizon at the SC radius r 1 = 2 G M / c 2 and only for α = α 0 ⩾ 3 space–time is singularity free for this value of the radius. These bounds exclude the previous existing metrics, for which the SC radius is a naked extended singularity. In addition it is shown that for α = α 0 > 5 space–time is approximately Ricci flat in a neighborhood of the event horizon such that the SC metric is a good approximation in this neighborhood. It is further shown that to strictly maintain the SC mass-pole at the origin r 1 = 0 without the presence of more severe singularities it is required a radial coordinate-dependent correction to the exponent α ( r 1 ) = α 0 + α 1 2 G M / ( c 2 r 1 ) with a negative coefficient α 1 0 . The energy-momentum density, pressures and equation of state are discussed.
119169087
Observing the temperature of the Big Bang through large scale structure
It is an interesting possibility that the Universe underwent a period of thermal equilibrium at very early times. One expects a residue of this primordial state to be imprinted on the large scale structure of space time. In this paper, we study the morphology of this thermal residue in a universe whose early dynamics is governed by a scalar field. We calculate the amplitude of fluctuations on large scales and compare it with the imprint of vacuum fluctuations. We then use the observed power spectrum of fluctuations on the cosmic microwave background to place a constraint on the temperature of the Universe before and during inflation. We also present an alternative scenario, where the fluctuations are predominantly thermal and near scale-invariant.
119514677
Isotropy and stability of the brane
We reexamine Wald’s no-hair theorem for global anisotropy in the brane world scenarios. We derive a set of sufficient conditions which must be satisfied bythe brane matter and bulk metric so that a homogeneous and anisotropic brane asymptotically evolves to a de Sitter spacetime in the presence of a positive cosmological constant on the brane. We discuss the violations of these sufficient conditions and we show that a negative nonlocal energy density or the presence of strong anisotropic stress (i.e., a magnetic field) may lead the brane to collapse. We discuss the generality of these conditions.
88506479
Parameterizing the flattening of galaxies rotation curves on an expanding locally anisotropic background
In this paper are discussed possible many body generalizations of the expanding locally anisotropic metric ansatz with respect to approximately Newtonian gravitational systems. This ansatz consistently describes local point-like matter distributions on the expanding Universe also allowing for a covariant parameterization of gravitational interactions at intermediate length scales. 
As an example of applicability it is modeled a disk galaxy model matching the physical parameters of the galaxy UGC2885 and it is shown that, by fine-tuning the metric functional parameter, the flattening of the galaxy rotation curve is fully parameterized by this metric. In addition it is numerically computed the mass-energy density corrections due to the expanding anisotropic background and explicitly shown that although there are negative contributions within the galaxy plane the total mass-energy density is strictly positive both at the galaxy plane and outside the galaxy plane. As the functional parameter for this metric is an exponential factor is required a floating point precision of $250$ significant digits for root finding routines and $200$ significant digits to evaluate the effective mass-energy density rendering a final precision of the results presented above double precision ($16$ significant digits). 
It is further shown that these results are consistent with the interpretation of the gravitational corrections as due to Dark Matter, in particular constituting a novel heuristic local parameterization for the Dark Matter distribution within the galaxy plane consistent with both local scale and cosmological scale physical laws which is useful to further investigate the local properties of Dark Matter.