Likelihood analysis of the pMSSM11 in light of LHC 13-TeV data

Hadronic Vacuum Polarization: (g-2)_{μ} versus Global Electroweak Fits

Hadronic vacuum polarization (HVP) is not only a critical part of the standard model (SM) prediction for the anomalous magnetic moment of the muon (g-2)_{μ}, but also a crucial ingredient for global fits to electroweak (EW) precision observables due to its contribution to the running of the fine-structure constant encoded in Δα_{had}^{(5)}. We find that with modern EW precision data, including the measurement of the Higgs mass, the global fit alone provides a competitive, independent determination of Δα_{had}^{(5)}|_{EW}=270.2(3.0)×10^{-4}. This value actually lies below the range derived from e^{+}e^{-}→hadrons cross section data, and thus goes into the opposite direction as would be required if a change in HVP were to bring the SM prediction for (g-2)_{μ} into agreement with the Brookhaven measurement. Depending on the energy where the bulk of the changes in the cross section occurs, reconciling experiment and SM predictions for (g-2)_{μ} by adjusting HVP would thus not necessarily weaken the case for physics beyond the SM (BSM), but to some extent shift it from (g-2)_{μ} to the EW fit. We briefly explore some options of BSM scenarios that could conceivably explain the ensuing tension.

Searching for supersymmetry and its avatars

Why continue looking for supersymmetry? Over and above the aesthetic and theoretical motivations from string theory, there are several longstanding pheno- menological motivations for TeV-scale super- symmetry, such as the electroweak scale, and the lightest supersymmetric particle as cold dark matter. Run 1 of the Large Hadron Collider (LHC) has actually provided three extra motivations, namely the stabilization of the electroweak vacuum, and successful predictions for the Higgs mass and couplings. How to look for it? There are several examples of emergent supersymmetry, the most recent being on the surfaces of topological insulators, and some sort of effective supersymmetry could be useful for boosting the power of laser arrays. At the LHC, attention is moving towards signatures that had previously been neglected, such as long-lived charged particles-which might be an opportunity for the MoEDAL experiment. This article is part of a discussion meeting issue 'Topological avatars of new physics'.

Search Strategy for Sleptons and Dark Matter Using the LHC as a Photon Collider

We propose a search strategy using the LHC as a photon collider to open sensitivity to scalar lepton (slepton ℓ[over ˜]) production with masses around 15 to 60 GeV above that of neutralino dark matter χ[over ˜]_{1}^{0}. This region is favored by relic abundance and muon (g-2)_{μ} arguments. However, conventional searches are hindered by the irreducible diboson background. We overcome this obstruction by measuring initial state kinematics and the missing momentum four-vector in proton-tagged ultraperipheral collisions using forward detectors. We demonstrate sensitivity beyond LEP for slepton masses of up to 200 GeV for 15≲Δm(ℓ[over ˜],χ[over ˜]_{1}^{0})≲60  GeV with 100  fb^{-1} of 13 TeV proton collisions. We encourage the LHC collaborations to open this forward frontier for discovering new physics.