Probing Squeezed Bino-Slepton Spectra with the Large Hadron Collider

Abstract

We consider a Minimal Supersymmetric Standard Model scenario in which the only light superparticles are a bino-like dark matter candidate and a nearly-degenerate slepton. It is notoriously difficult to probe this scenario at the Large Hadron Collider, because the slepton pair-production process yields a final state with soft leptons and small missing transverse energy. We study this scenario in the region of parameter space where the mass difference between the lightest neutralino and the lightest slepton ($\Delta m$) is $\lesssim 60\mathrm{GeV}$, focusing on the process in which an additional radiated jet provides a transverse boost to the slepton pair. We then utilize the angular separation of the leptons from each other and from the missing transverse energy, as well as the angular separation between the jet and the missing transverse energy, to distinguish signal from background events. We also use the reconstructed ditau mass, the $\cos {\theta }_{{\ell }^{+}{\ell }^{-}}^{\ast }$ variable, and for larger $\Delta m$, a lower bound on the lepton $p_T$. These cuts can dramatically improve both signal sensitivity and the signal-to-background ratio, permitting discovery at the Large Hadron Collider with reasonable integrated luminosity over the interesting region of parameter space. Using our search strategy the LHC will be able to exclude $m_{\tilde{\mu }}\approx 200$ GeV for $\Delta m\lesssim 60$ GeV at $1.5-3\sigma$ with 1000 fb${}^{-1}$ of integrated luminosity. Although we focus on a particular model, the results generalize to a variety of scenarios in which the dark matter and a leptonic partner are nearly degenerate in mass, and especially to scenarios featuring a scalar mediator.

21 pages, 14 figures, 5 tables, as published in Physical Review D

References in corpus (10)

• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• The WIMPless Miracle: Dark Matter Particles without Weak-scale Masses or Weak Interactions
• Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV with the ATLAS detector
• Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV
• Monojet plus soft dilepton signal from light higgsino pair production at LHC14
• Probing Compressed Sleptons at the LHC using Vector Boson Fusion Processes
• A boost for the EW SUSY hunt: monojet-like search for compressed sleptons at LHC14 with 100 fb^-1
• Fermion WIMPless Dark Matter at DeepCore and IceCube
• Detection Prospects for Majorana Fermion WIMPless Dark Matter