Perturbative extension of the standard model with a 125 GeV Higgs and Magnetic Dark Matter

We introduce a perturbative extension of the standard model featuring a new dark matter sector together with a 125 GeV Higgs. The new sector consists of a vector-like heavy electron E, a complex scalar electron S and a standard model singlet Dirac fermion \chi. The interactions among the dark matter candidate \chi and the standard model particles occur via loop-induced processes involving the operator SE\chi y, with y being the Yukawa-like coupling. The model is an explicit underlying realization of the light magnetic dark matter effective model introduced earlier to alleviate the tension among several direct dark matter search experiments. We further constrain the parameters of the underlying theory using results from the Large Hadron Collider. The extension can accommodate the recently observed properties of the Higgs-like state and leads to interesting predictions. Finally we show that the model's collider phenomenology and constraints nicely complement the ones coming from dark matter searches.Comment: Final version to match the one published in Phys. Rev.

HEJ 2: High energy resummation for hadron colliders

We present HEJ 2, a new implementation of the High Energy Jets formalism for high-energy resummation in hadron-collider processes as a flexible Monte Carlo event generator. In combination with a conventional fixed-order event generator, HEJ 2 can be used to obtain greatly improved predictions for a number of phenomenologically important processes by adding all-order logarithmic corrections in . A prime example for such a process is the gluon-fusion production of a Higgs boson in association with widely separated jets, which constitutes the dominant background to Higgs boson production in weak-boson fusion

Composite Higgs to two Photons and Gluons

We introduce a simple framework to estimate the composite Higgs boson coupling to two-photon in Technicolor extensions of the standard model. The same framework allows us to predict the composite Higgs to two-gluon process. We compare the decay rates with the standard model ones and show that the corrections are typically of order one. We suggest, therefore, that the two-photon decay process can be efficiently used to disentangle a light composite Higgs from the standard model one. We also show that the Tevatron results for the gluon-gluon fusion production of the Higgs either exclude the techniquarks to carry color charges to the 95% confidence level, if the composite Higgs is light, or that the latter must be heavier than around 200 GeV.Comment: RevTex 7 pages, 6 figure

Custodial Vector Model

We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum and interactions with the standard model fields lead to distinct signatures at the LHC in the diboson, dilepton and associated Higgs channels.Comment: 35 pages, 45 figure

W Plus Multiple Jets at the LHC with High Energy Jets

We study the production of a W boson in association with n hard QCD jets (for n>=2), with a particular emphasis on results relevant for the Large Hadron Collider (7 TeV and 8 TeV). We present predictions for this process from High Energy Jets, a framework for all-order resummation of the dominant contributions from wide-angle QCD emissions. We first compare predictions against recent ATLAS data and then shift focus to observables and regions of phase space where effects beyond NLO are expected to be large.Comment: 19 pages, 9 figure

Pseudo Goldstone Bosons Phenomenology in Minimal Walking Technicolor

We construct the non-linear realized Lagrangian for the Goldstone Bosons associated to the breaking pattern of SU(4) to SO(4). This pattern is expected to occur in any Technicolor extension of the standard model featuring two Dirac fermions transforming according to real representations of the underlying gauge group. We concentrate on the Minimal Walking Technicolor quantum number assignments with respect to the standard model symmetries. We demonstrate that for, any choice of the quantum numbers, consistent with gauge and Witten anomalies the spectrum of the pseudo Goldstone Bosons contains electrically doubly charged states which can be discovered at the Large Hadron Collider.Comment: 25 pages, 5 figure

Constraints on Majorana dark matter from a fourth lepton family

We study the possibility of dark matter in the form of heavy neutrinos from a fourth lepton family with helicity suppressed couplings such that dark matter is produced thermally via annihilations in the early Universe. We present all possible constraints for this scenario coming from LHC and collider physics, underground direct detectors, neutrino telescopes, and indirect astrophysical searches. Although we embed the WIMP candidate within a model of composite dynamics, the majority of our results are model independent and applicable to all models where heavy neutrinos with suppressed couplings account for the dark matter abundance