We study the possibility of observing lepton number violation in the right-handed sneutrino sector of the next-to-minimal supersymmetric Standard Model extended with right-handed neutrinos. The scalar potential introduces a lepton number violating mass term for the right-handed sneutrinos, which generates a phase difference that results in oscillations between the sneutrino and antisneutrino. If we have light Higgsinos and right-handed sneutrinos, the sneutrino decay width is determined by the tiny Yukawa couplings, which allows the phase difference to accumulate before the sneutrino decays. We investigate the possibilities of producing sneutrino pairs resonantly through a heavy Higgs of such a model and the ability of seeing a lepton number violating signature emerging from sneutrinos at the Large Hadron Collider. We also discuss how a possible future signal of this type could be used to determine the neutrino Yukawa couplings.

We report on recent studies of photon-induced (PI) contributions to di-lepton production and their implications for Beyond Standard Model (BSM) $Z^\prime$-bosons searches at the LHC.

We show the SM prediction of di-lepton production at the LHC where to the usual Drell-Yan production we add the contribution from Photon-Initiated processes. We discuss the effects of the inclusion of photon interactions in the high invariant mass region (TeV region) and their consequences on BSM heavy Z'-boson searches.

We explore the effects of Photon Induced (PI) production of a dilepton final state in the Large Hadron Collider environment. Using QED Parton Distribution Function (PDF) sets we can treat the photons as real partons inside the protons and compare their yield directly to that of the Drell-Yan (DY) process. In particular, we concentrate on an error analysis of the two mechanisms. In order to do so, we use the NNPDF set, which comes with a set of replicas to estimate the systematic PDF error. On the one hand, we find that the PI contribution becomes dominant over DY above a dilepton invariant mass of 3 TeV. On the other hand, the PI predictions are affected by a large error coming from the QED PDFs, well above the one affecting the DY mode. We assess the impact of these uncertainties in the context of resonant and non-resonant searches for a neutral massive vector boson (Z') through the differential cross section and Forward-Backward Asymmetry (AFB) observables as a function of the dilepton invariant mass. While the former is subject to the aforementioned significant residual errors the latter shows the systematic error cancellation expected (recall that AFB is a ratio of cross sections) even in presence of PI contributions, so that the recently emphasized key role played by AFB as a valid tool for both Z' discovery and interpretation in both resonant and non-resonant mode is further consolidated.

We define a focus point (FP) asymmetry, A(FP), obtained by integrating the normalized transverse momentum distribution of either lepton produced in the Drell-Yan (DY) process below and above a point where a variety of popular Z' models all have the same magnitude. For a given Z' mass the position of this FP is predictable, depending only on the collider energy and on the low transverse momentum cut chosen in the normalization procedure. The resulting A(FP) is very sensitive to the Z' width and can be used to constrain this parameter in experimental fits.

A number of searches at the LHC looking for low mass ($2m_{mu} - 62 mathrm{GeV}$) bosons in $sqrt{s} = 8 mathrm{TeV}$ data have recently been published. We summarise the most pertinent ones, and look at how their limits affect a variety of supersymmetric models which can give rise to such light bosons: the 2HDM (Types I and II), the NMSSM, and the nMSSM.

Searches for Z bosons are most sensitive in the dilepton channels at hadron colliders.Whilst finite width and interference effects do affect the modifications the presence of BSM physics makes to Standard Model (SM) contributions, generic searches are often designed to minimize these.The experimental approach adopted works well in the case of popular models that predict a single and narrow Z boson allowing these effects to effectively be neglected.Conversely, finite width and interference effects may have to be taken into account in experimental analyses when such Z states are wide or where several states are predicted.We explore the consequences of these effects in the 4-Dimensional Composite Higgs Model (4DCHM) which includes multiple new Z bosons and where the decays of these resonances to non-SM fermions can result in large widths.

We present the Large Hadron Collider (LHC) discovery potential in the Z' sector of a U(1)_{B-L} enlarged Standard Model also encompassing three heavy Majorana neutrinos, for \sqrt{s}=7 centre-of-mass energy, considering both the Z'_{B-L}\rightarrow e^+e^- and Z'_{B-L}\rightarrow \mu^+\mu^- decay channels. Electrons provide a higher sensitivity to smaller couplings at small Z'_{B-L} boson masses than do muons. The run of the LHC at \sqrt{s}=7 TeV, assuming at most \int \mathcal{L} \sim 1 fb^{-1}, will be able to give similar results to those that will be available soon at the Tevatron in the lower mass region, and to extend them for a heavier M_{Z'}. A 5\sigma discovery could be possible up to M_{Z'}=1.2(0.9) TeV at the LHC(Tevatron), while a 2\sigma exclusion at the LHC could be possible up to M_{Z'}=1.6 TeV. The new gauge coupling g'_1 can been probed, at 5\sigma, down to \sim (3 \div 4) \cdot 10^{-2} with electrons and down to \sim (4 \div 5) \cdot 10^{-2} with muons, both at the LHC and at the Tevatron, for M_{Z'}=600 GeV. The Z' boson in this model exhibits novel signatures at the LHC, as multi-lepton and multi-jet decays via heavy neutrinos, that allow one to measure the heavy neutrino masses involved. Lastly, the simultaneous measurement of both the heavy neutrino mass and decay length (over a large region of parameter space, the heavy neutrinos are rather long-lived particles) enables an estimate of the absolute mass of the parent light neutrino.

We review theoretical and experimental results on CP violation summarizing the discussions in the working group on CP violation at the UK phenomenology workshop 2000 in Durham.