2HDM Charged Higgs Boson Searches at the LHC: Status and Prospects

We review status and prospects of searches for the charged Higgs boson of 2-Higgs Doublet Models of all Yukawa types at the Large Hadron ColliderComment: 9 pages, 8 figures, 2 tables, talk given at the Workshop `Charged 2016: Prospects for Charged Higgs Discovery at Colliders', 3-6 October 2016, Uppsala, Swede

Improving the discovery potential of charged Higgs bosons at Tevatron Run 2

By exploiting the full process $p\bar p\to t\bar b H^-$, in place of the standard Monte Carlo procedure of factorising production and decay, $p\bar p\to t\bar t$ followed by $\bar t\to\bar b H^-$, we show how to improve the discovery reach of the Tevatron (Run 2) in charged Higgs boson searches, in the large $\tan\beta$ region. This is achieved in conjunction with dedicated cuts on a `transverse mass' distribution sensitive to the Higgs boson mass and to `polarisation' effects in the $H^-\to\tau^-\bar\nu_\tau$ decay channel.Comment: 12 pages, LaTeX, 5 figures (one figure added, discussion slightly changed: version to appear in JHEP

Possible Explanation of the Electron Positron Anomaly at 17 MeV in 8Be^8Be Transitions Through a Light Pseudoscalar

We estimate the values of Yukawa couplings of a light pseudoscalar A with a mass of about 17 MeV, which would explain the $^8Be$ 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.Comment: 12 pages, discussion of nuclear shell model corrected, to appear in JHE

The 750 GeV diphoton excess and its explanation in 2-Higgs Doublet Models with a real inert scalar multiplet

We 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 $H$ from the doublet fields into the diphoton mode can be significantly enhanced, by up to a factor of $10^3$, 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 $H\to \gamma\gamma$ decay mode. Through this enhancement, we obtain a suitable cross section of the $gg\to H \to \gamma\gamma$ process to explain the data with the fixed mass of $H$ being 750 GeV.Comment: Version accepted in PRD, Appendix adde

Two Higgs bosons near 125 GeV in the complex NMSSM and the LHC Run-I data

We analyse the impact of explicit CP-violation in the Higgs sector of the Next-to-Minimal Supersymmetric Standard Model (NMSSM) on its consistency with the Higgs boson data from the Large Hadron Collider (LHC). Through detailed scans of the parameter space of the complex NMSSM for certain fixed values of one of its CP-violating (CPV) phases, we obtain a large number of points corresponding to five phenomenologically relevant scenarios containing $\sim 125$ GeV Higgs boson(s). We focus, in particular, on the scenarios where the visible peaks in the experimental samples can actually be explained by two nearly mass-degenerate neutral Higgs boson states. We find that some points corresponding to these scenarios give an overall slightly improved fit to the data, more so for non-zero values of the CPV phase, compared to the scenarios containing a single Higgs boson near 125 GeV.Comment: 22 pages, 3 figures. Substantially revised text, improved results and figures, overall conclusions unchanged. Some added references. Version to appear in the special issue "Supersymmetry beyond the (N)MSSM" of AHE

The constrained E6SSM

We discuss the predictions of a constrained version of the exceptional supersymmetric standard model (cE6SSM), with a universal high energy soft scalar mass, soft trilinear coupling and soft gaugino mass. The spectrum includes a light gluino, a light wino-like neutralino and chargino pair and a light bino-like neutralino, with other sparticle masses except the lighter stop being much heavier. We also discuss scenarios with an extra light exotic colour triplet of fermions and scalars and a TeV scale Z', which lead to early exotic physics signals at the LHC.Comment: To appear in proceedings of The 2009 Europhysics Conference on High Energy Physics, 16-22 July 2009 Krakow, Poland; 4 page

Single production of charged Higgs bosons at linear colliders

We discuss single charged Higgs boson production from $e^+e^-$ annihilation at next generation linear colliders. They can be important to study the phenomenology of charged Higgs bosons, especially when charged Higgs bosons are too heavy to be produced by the pair production mechanism. Cross sections for various single production processes are evaluated at the leading order. Our analysis shows that in some parameter regions the phenomenology of charged Higgs bosons can be explored even beyond the kinematic limit for pair production by using single production processes.Comment: Talk given by S. Kanemura at the Linear Collider Workshop 2000, October 24-28, 2000, Fermila