Abstract
The minimal supersymmetric (SUSY) standard model (MSSM) augmented by right chiral sneutrinos may lead to one such sneutrino serving as the lightest supersymmetric particle and a non-thermal dark matter candidate, especially if neutrinos have Dirac masses only. In such cases, if the lightest MSSM particle is a stau, the signal of SUSY at the LHC consists in stable charged tracks which are distinguishable from backgrounds through their time delay between the inner tracker and the muon chamber. We show how to determine in such scenarios the mass hierarchy between the lightest neutralino and right sleptons of the first two families. The techniques of neutralino reconstruction, developed in earlier works, are combined with the endpoint of the variable MT 2 in smuon (selectron) decays for this purpose. We show that one can thus determine the mass hierarchy for smuons (selectrons) and neutralinos up to 1 TeV, to the level of 5-10%.
Highlights
JHEP09(2018)143 the two cases [22, 23].2 Interestingly, one can still envision other situations where direct searches are inconsequential on the one hand, while LHC signals, on the other, are of a drastically different kind
The minimal supersymmetric (SUSY) standard model (MSSM) augmented by right chiral sneutrinos may lead to one such sneutrino serving as the lightest supersymmetric particle and a non-thermal dark matter candidate, especially if neutrinos have Dirac masses only
We show how to determine in such scenarios the mass hierarchy between the lightest neutralino and right sleptons of the first two families
Summary
In order to decipher the actual ordering of the masses in the SUSY electroweak sector, in particular of χ01 and μR/eR, we have to reconstruct the following three particles, viz., τ1, χ01 and μR/eR, with the μR and eR being considered to be degenerate in mass. In order to reconstruct the slepton masses (mμR, meR), we consider the Drell-Yan production of μR μ∗R (eR e∗R) followed by the slepton’s decay into a lepton (μ/e), a τ1 and a τ , mediated by an off-shell or an on-shell χ01 depending on their mass ordering. MT 2 is a useful variable for measuring the mass of a particle when it is pair-produced in a hadron collider and thereafter decays into a visible object along with invisible particles, giving rise to missing transverse momentum. MT 2 variable can be relevant for the reconstruction of slepton masses for the first signature involving a single τ -tagged jet. Pair production of strongly interacting superparticles leads to similar final states but exhibit different topologies (as shown in figure 1 (right)), namely the cascade decay has additional jets at the parton level. As E/ T plays an important role in the construction of the MT 2 variable, which will, at the end be our most important observable for the mass reconstruction of the sleptons, removing the cascade processes with this cut will help in achieving faithful reconstructions of the sleptons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
