1,721,472 research outputs found
2HDM charged Higgs Boson searches at the LHC: Status and Prospects
No full textWe review status and prospects of searches for the charged Higgs boson of 2-Higgs Doublet Models of all Yukawa types at the Large Hadron Collide
Matrix-element corrections to g g / q anti-q -> Higgs in HERWIG
No full textWe describe the HERWIG implementation of real matrix-element corrections to direct Higgs hadroproduction at Tevatron and Large Hadron Collider (LHC) and compare it to other approaches existing in literature and describing the transverse momentum distribution of the Higgs boson
Enhanced four-body decays of charged Higgs Bosons into off-shell pseudoscalar Higgs and W± Boson pairs in a lepton-specific 2-Higgs Doublet Model
No full textWe study the time-honoured decay H±→AW± but for the first time, we do so for the case of both A and W± being off-shell, therefore computing a 1→4 body decay. We show that the corresponding decay rate not only extends the reach of H± searches to small masses of the latter but also that the results of our implementation differ significantly from the yield of the 1→3 body decay over the phase space region in which the latter is normally used. We show the phenomenological relevance of this implementation in the case of the so-called lepton-specific 2-Higgs Doublet Model (2HDM) over the mass region wherein the aforementioned 1→4 body decay can dominate just beyond the top (anti)quark mass. This mass region is accessible in the lepton-specific 2HDM as the Yukawa couplings are such that limits from b→sγ and τ→μντνμ¯ observables on MH± are rather mild. However, we emphasise that similar effects may occur in other 2HDM types, as the W±H∓A vertex is 2HDM type independent
Supersymmetry beyond minimality: from theory to experiment
No full textThe book contains five parts. Part I is core material and is necessary to develop any of the following parts, which are in turn largely independent from one another. Part I could be the material for a 1-semester course, whereas any of the latter can be taught separately in more advanced and shorter modules. The authors discuss non-minimal supersymmetry models, in a bottom-up approach that interconnects experimental phenomena in the fermionic and bosonic sectors, many of which postdate the inception of supersymmetry, such as the discovery of neutrino masses and the evidence of a Higgs boson, or which are simply not covered in previous textbooks, like CP and lepton flavour violation
Constraints on parameter space from perturbative unitarity in models with three scalar doublets
No full textWe calculate an -wave amplitude matrix for all the possible 2--to--2 body scalar boson elastic scatterings in models with three scalar doublets, including contributions from the longitudinal component of weak gauge bosons via the Equivalence Theorem Approximation. Specifically, we concentrate on the two cases with two[one] active plus one[two] inert doublet fields, referred to as I(1+2)HDM[I(2+1)HDM], under CP conservation. We obtain three analytically irreducible sub-matrices with the form and eighteen eigenvalues for the amplitude matrix as an independent set, where the same formula can be applied to both models. By requiring a perturbative unitarity condition, we can constrain the magnitude of quartic coupling constants in the Higgs potential. This constraint, in particular in the I(1+2)HDM, can be translated into a bound on masses of extra active scalar bosons. Furthermore, when Standard Model-like Higgs boson couplings with weak gauge bosons are deviated from the Standard Model predictions, the unitarity condition provides an upper limit on the masses. We find that stronger upper bounds on the masses of the active CP-even and CP-odd Higgs bosons are obtained under the constraints from the unitarity and vacuum stability conditions, as well as the electroweak , and parameters, as compared to those in 2-Higgs Doublet Models with a softly-broken symmetry
Summary of the 'Electroweak and Searches in DIS and Hadron Colliders' Working Group
No full textWe present here the summary of the Electroweak and Searches in DIS and Hadron Colliders working group activities at the DIS 2010 conference. The theory contributions will be presented first, followed by the experimental ones. The experimental results include measurements from the Tevatron (CDF and DØ) and HERA (H1 and ZEUS) experiments, and studies from the LHC (ATLAS and CMS). Results from the B factories (BaBar and Belle) and from NA62 are also summarised
750 GeV diphoton excess and its explanation in two-Higgs-doublet models with a real inert scalar multiplet
No full textWe discuss a possible explanation of the recently observed diphoton excess at around 750 GeV as seen by the ATLAS and CMS experiments at the Large Hadron Collider. We calculate the cross section of the diphoton signature in 2-Higgs Doublet Models with the addition of a real isospin scalar multiplet without a vacuum expectation value, where a neutral component of such a representation can be a dark matter candidate. We find that the branching fraction of an additional CP-even Higgs boson from the doublet fields into the diphoton mode can be significantly enhanced, by up to a factor of , with respect to the case of the simple 2-Higgs Doublet Model. Such a sizable enhancement is realized due to multi-charged inert particle loops entering the decay mode. Through this enhancement, we obtain a suitable cross section of the process to explain the data with the fixed mass of being 750 GeV
Possible explanation of the electron positron anomaly at 17 MeV in 8Be transitions through a light pseudoscalar
No full textWe estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the anomaly observed in the Atomki pair spectrometer experiment. The resulting couplings of A to up and down type quarks are about 0.3 times the coupling of the standard Higgs boson. Then constraints from K and B decays require that loop contributions to flavour changing vertices cancel at least at the 10% level. Constraints from beam dump experiments require the coupling of A to electrons to be larger than about 4 times the coupling of the standard Higgs boson, leading to a short enough A life time consistent with an explanation of the anomaly
Heavy neutrinos, Z' and Higgs bosons at the LHC: new particles from an old symmetry
No full textA new era in particle physics is being spurred on by new data from the Large Hadron Collider. Non-vanishing neutrino masses represent firm observational evidence of new physics beyond the Standard Model. An extension of the latter, based on a SU(3)C × SU(2)L × U(1)Y × U(1)B-L symmetry, incorporating an established Baryon minus Lepton number invariance, is proposed as a viable and testable solution to the neutrino mass problem. We argue that LHC data will probe all the new content of this model: heavy neutrinos, an extra gauge boson emerging from spontaneous breaking of the additional gauge group at the TeV scale, onset by a new heavier Higgs boson, also visible at the CERN proton-proton collider. An even more exciting version of this model is the one exploiting Supersymmetry: firstly, it incorporates all its well-known benefits; secondly, it alleviates the flaws of its more minimal realisations. Finally, this model provides a credible cold Dark Matter candidate, the lightest sneutrino, detectable in both underground and collider experiment
LHC Signals of a Heavy CP-even Higgs Boson in the NMSSM via Decays into a Z and a Light CP-odd Higgs State
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