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We use the current CMS and ATLAS data for the leptonic $pp to WW, WZ$ channels to show that diboson production is, for a broad class of flavour models, already competitive with LEP-1 measurements for setting bounds on the dimension six operators parametrising the anomalous couplings between the quarks and the electroweak gauge bosons, at least under the assumption that any new particle is heavier than a few TeV. We also make an estimate of the HL-LHC reach with $3$ ab$^{-1}$. We comment on possible BSM interpretations of the bounds, and show the interplay with other searches for a simplified model with vector triplets. We further study the effect of modified $Z$-quark-quark couplings on the anomalous triple gauge coupling bounds. We find that their impact is already significant and that it could modify the constraints on $delta g_{1z}$ and $delta kappa_gamma$ by as much as a factor two at the end of HL-LHC ($lambda_gamma$ is only marginally affected), requiring a global fit to extract robust bounds. We stress the role of flavour assumptions and study explicitly flavour universal and minimal flavour violation scenarios, illustrating the differences with results obtained for universal theories.
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We propose novel collider searches which can significantly improve the LHC reach to new gauge bosons $Z$ with mixed anomalies with the electroweak (EW) gauge group. Such a $Z$ necessarily acquires a Chern-Simons coupling to the EW gauge bosons and these couplings can drive both exotic $Z$ decays into $Zgamma$ if the new gauge boson is sufficiently light, as well as $Z$ decays into EW gauge bosons.While the exotic decay rate of the heavy $Z$ into $Zgamma$ is too small to be observed at the LHC, for a light $Z$, we show the potential of a lepton jet search in association with a photon to probe the rare decay $Z to Z gamma$.
The first run of the LHC showed hints of a new resonance with mass near $1.9$ TeV decaying into electroweak gauge boson pairs as well as into dijets. While Run 2 has neither confirmed nor ruled out such a resonance, it has yielded new constraints on models attempting to explain these decays. Additionally in $W$ models where this new resonance is a charged vector boson that is a weak isospin singlet there is the potential for conflict with the electroweak precision $T$ parameter. We construct variants of a $W$ resonance model that provide an excellent fit to both Run 1 and Run 2 data, as well as electroweak precision measurements. The model also predicts a neutral vector boson, a $Z$, with mass close to $3$ TeV. This $Z$ is compatible with the intriguing Run 2 observation of a dielectron pair with invariant mass of $2.9$ TeV at CMS.
The ATLAS collaboration has recently reported a 2.6 sigma excess in the search for a heavy resonance decaying into a pair of weak gauge bosons. Only fully hadronic final states are being looked for in the analysis. If the observed excess really originates from the gauge bosons decays, other decay modes of the gauge bosons would inevitably leave a trace on other exotic searches. In this paper, we propose the use of the Z boson decay into a pair of neutrinos to test the excess. This decay leads to a very large missing energy and can be probed with conventional dark matter searches at the LHC. We discuss the current constraints from the dark matter searches and the prospects. We find that optimizing these searches may give a very robust probe of the resonance, even with the currently available data of the 8 TeV LHC.
We discuss NMSSM scenarios in which the lightest Higgs boson $h_1$ is consistent with the small LEP excess at about 98 GeV in $e^+e^- to Zh$ with $hto banti b$ and the heavier Higgs boson $h_2$ has the primary features of the LHC Higgs-like signals at 125 GeV, including an enhanced $gammagamma$ rate. Verification or falsification of the 98 GeV $h_1$ may be possible at the LHC during the 14 TeV run. The detection of the other NMSSM Higgs bosons at the LHC and future colliders is also discussed, as well as dark matter properties of the scenario under consideration.
Within the Minimal Supersymmetric Standard Model (MSSM), we study the production of the neutral scalar and pseudoscalar as well as the charged Higgs bosons together with fermions or sfermions in deep inelastic $ep$ scattering at $sqrt{s}=1.6$ TeV. We focus on the parameter space where a Higgs particle is likely to be invisible at LEP2 and LHC. Although we choose gaugino/higgsino mixing scenarios that maximize the corresponding production rates we find only for the production of the scalar Higgs bosons in the non-supersymmetric channels non-negligible cross sections of the order of $10^2$ fb.
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