Anomalous gauge couplings from composite Higgs and warped extra dimensions

We examine trilinear and quartic anomalous gauge couplings (AGCs) generated in composite Higgs models and models with warped extra dimensions. We first revisit the SU(2) L × U(1) Y effective Lagrangian and derive the charged and two-photon neutral AGCs. We derive the general perturbative contributions to the pure field-strength operators from spin 0, $\frac{1}{2}$ , 1 resonances by means of the heat kernel method. In the composite Higgs framework, we derive the pattern of expected deviations from typical SO( N ) embeddings of the light composite top partner. We then study a generic warped extra dimension framework with AdS 5 background, recasting in few parameters the features of models relevant for AGCs. We also present a detailed study of the latest bounds from electroweak and Higgs precision observables, with and without brane kinetic terms. For vanishing brane kinetic terms, we find that the S and T parameters exclude KK gauge modes of the RS custodial [non-custodial] scenario below 7 . 7 [14 . 7] TeV, for a brane Higgs and below 6 . 6 [8 . 1] TeV for a Pseudo Nambu-Goldstone Higgs, at 95% CL. These constraints can be relaxed in presence of brane kinetic terms. The leading AGCs are probing the KK gravitons and the KK modes of bulk gauge fields in parts of the parameter space. In these scenarios, the future CMS and ATLAS forward proton detectors could be sensitive to the effect of KK gravitons in the multi-TeV mass range

WIMP and SIMP dark matter from the spontaneous breaking of a global group

We propose and study a scalar extension of the Standard Model which respects a ℤ3 symmetry remnant of the spontaneous breaking of a global U(1)DM symmetry. Consequently, this model has a natural dark matter candidate and a Goldstone boson in the physical spectrum. In addition, the Higgs boson properties are changed with respect to the Standard Model due to the mixing with a new particle. We explore regions in the parameter space taking into account bounds from the measured Higgs properties, dark matter direct detection as well as measurements of the effective number of neutrino species before recombination. The dark matter relic density is determined by three classes of processes: the usual self-annihilation, semi-annihilation and purely dark matter 3 → 2 processes. The latter has been subject of recent interest leading to the so-called `Strongly Interacting Massive Particle' (SIMP) scenario. We show under which conditions our model can lead to a concrete realization of such scenario and study the possibility that the dark matter self-interactions could address the small scale structure problems. In particular, we find that in order for the SIMP scenario to work, the dark matter mass must be in the range 7−115 MeV, with the global symmetry energy breaking scale in the TeV range

Excluding the light dark matter window of a 331 model using LHC and direct dark matter detection data

We sift the impact of the recent Higgs precise measurements, and recent dark matter direct detection results, on the dark sector of an electroweak extension of the Standard Model that has a complex scalar as dark matter. We find that in this model the Higgs decays with a large branching ratio into dark matter particles, and charged scalars when these are kinematically available, for any coupling strength differently from the so called Higgs portal. Moreover, we compute the abundance and spin-independent WIMP-nucleon scattering cross section, which are driven by the Higgs and Z? boson processes. We decisively exclude the 1?500 GeV dark matter window and find the most stringent lower bound in the literature on the scale of symmetry breaking of the model namely 10 TeV, after applying the LUX-2013 limit. Interestingly, the projected XENON1T constraint will be able to rule out the entire 1 GeV?1000 GeV dark matter mass range. Lastly, for completeness, we compute the charged scalar production cross section at the LHC and comment on the possibility of detection at current and future LHC runnings

BFKL equation for an integrated gluon density

We show how it is possible to rewrite the BFKL equation for the unintegrated gluon distribution, in terms of integrated gluons, similar to that used in DGLAP. We add to our equation the next-to-leading log terms which provide exact energy-momentum conservation and account for the kinematic constraint in real gluon emission. In this way the equation includes the major part of the higher-order corrections to BFKL evolution. We discuss the possibility to obtain a unified BFKL–DGLAP evolution equation relevant to processes at the LHC where both log (1/x) and log Q2 are large simultaneously

Conductivity in the gravity dual to massive ABJM and the membrane paradigm

In this paper we analyze the effect of the massive deformation of the ABJM model on the calculation of conductivity of the dual theory. We show that some of the difficulties presented by the dual geometry, in particular the construction of black holes therein, can be at least partially circumvented by adopting a membrane paradigm-like computation of the conductivity, which requires us to know just the effect of the deformation on the horizon of a black hole in AdS 4 . The deformation at the horizon itself is found by first deforming the flat space near the horizon, and then using the corresponding solution near the horizon as initial conditions for the Einstein’s equations. We find the same result, showing an increase in conductivity, using two types of membrane paradigm computations

A search for inverse magnetic catalysis in thermal quark–meson models

We explore the parameter space of the two-flavor thermal quark–meson model and its Polyakov loop-extended version under the influence of a constant external magnetic field B . We investigate the behavior of the pseudo critical temperature for chiral symmetry breaking taking into account the likely dependence of two parameters on the magnetic field: the Yukawa quark–meson coupling and the parameter <math altimg="si1.gif" xmlns="http://www.w3.org/1998/Math/MathML"><msub><mrow><mi>T</mi></mrow><mrow><mn>0</mn></mrow></msub></math> of the Polyakov loop potential. Under the constraints that magnetic catalysis is realized at zero temperature and the chiral transition at <math altimg="si2.gif" xmlns="http://www.w3.org/1998/Math/MathML"><mi>B</mi><mo>=</mo><mn>0</mn></math> is a crossover, we find that the quark–meson model leads to thermal magnetic catalysis for the whole allowed parameter space, in contrast to the present picture stemming from lattice QCD

Evolution in opening angle combining DGLAP and BFKL logarithms

We present an evolution equation which simultaneously sums the leading BFKL and DGLAP logarithms for the integrated gluon distribution in terms of a single variable, namely the emission angle of the gluon. This form of evolution is appropriate for Monte Carlo simulations of events of high energy pp (and pp¯ ) interactions, particularly where small x events are sampled

Radiative corrections in bumblebee electrodynamics

We investigate some quantum features of the bumblebee electrodynamics in flat spacetimes. The bumblebee field is a vector field that leads to a spontaneous Lorentz symmetry breaking. For a smooth quadratic potential, the massless excitation (Nambu–Goldstone boson) can be identified as the photon, transversal to the vacuum expectation value of the bumblebee field. Besides, there is a massive excitation associated with the longitudinal mode and whose presence leads to instability in the spectrum of the theory. By using the principal-value prescription, we show that no one-loop radiative corrections to the mass term is generated. Moreover, the bumblebee self-energy is not transverse, showing that the propagation of the longitudinal mode cannot be excluded from the effective theory

Generalized q -deformed correlation functions as spectral functions of hyperbolic geometry

We analyze the role of vertex operator algebra and 2d amplitudes from the point of view of the representation theory of infinite-dimensional Lie algebras, MacMahon and Ruelle functions. By definition p-dimensional MacMahon function, with p≤3 , is the generating function of p -dimensional partitions of integers. These functions can be represented as amplitudes of a two-dimensional c = 1 CFT, and, as such, they can be generalized to p>3 . With some abuse of language we call the latter amplitudes generalized MacMahon functions. In this paper we show that generalized p-dimensional MacMahon functions can be rewritten in terms of Ruelle spectral functions, whose spectrum is encoded in the Patterson–Selberg function of three-dimensional hyperbolic geometry

Topological vortices in generalized Born–Infeld–Higgs electrodynamics

A consistent BPS formalism to study the existence of topological axially symmetric vortices in generalized versions of the Born–Infeld–Higgs electrodynamics is implemented. Such a generalization modifies the field dynamics via the introduction of three nonnegative functions depending only in the Higgs field, namely, G(|ϕ|) , w(|ϕ|) , and V(|ϕ|) . A set of first-order differential equations is attained when these functions satisfy a constraint related to the Ampère law. Such a constraint allows one to minimize the system’s energy in such way that it becomes proportional to the magnetic flux. Our results provides an enhancement of the role of topological vortex solutions in Born–Infeld–Higgs electrodynamics. Finally, we analyze a set of models entailing the recovery of a generalized version of Maxwell–Higgs electrodynamics in a certain limit of the theory