Abstract
We study LHC signatures of displaced vertices and long-lived charged particles within the context of the Next-to-Minimal Supersymmetric Standard Model with right-handed (RH) sneutrinos. In this construction the RH neutrino can be produced directly from Higgs decays or in association with a RH sneutrino when the latter is the lightest supersymmetric particle. The RH neutrino is generally long-lived, since its decay width is proportional to the neutrino Yukawa, a parameter which is predicted to be small. The RH neutrino late decay can therefore give rise to displaced vertices at the LHC, which can be identified through the decay products, which involve two leptons (2ℓ + T ) or a lepton with two jets (ℓjj). We simulate this signal for the current LHC configuration (a centre of mass of 8 TeV and an integrated luminosity of $ \mathcal{L} $ = 20 fb−1), and a future one (13 TeV and $ \mathcal{L} $ = 100 fb−1). We show that a region of the parameter space of this model can be probed and that the RH neutrino mass can be reconstructed from the end-point of the two-lepton invariant mass distribution or the central value of the mass distribution for two jets plus one lepton. Another exotic signature of this construction is the production of a long-lived stau. If the stau is the next-to-lightest supersymmetric particle, it can decay through diagrams involving the small neutrino Yukawa, and would escape the detector leaving a characteristic trail. We also simulate this signal for various benchmark points and show that the model can be within the reach of the future run of the LHC.
Highlights
JHEP05(2014)035 scalar Higgs which addresses the μ problem [15] and provides extra Higgs and neutralino states, while an extra singlet superfield, N, accounts for RH neutrino and sneutrino states
We show that a region of the parameter space of this model can be probed and that the RH neutrino mass can be reconstructed from the end-point of the two-lepton invariant mass distribution or the central value of the mass distribution for two jets plus one lepton
In refs. [12, 16] we showed that the RH sneutrino relic density can be adjusted by playing with the free parameters λN, AλN and mNwithout significantly affecting the NMSSM phenomenology
Summary
The recently discovered Higgs particle at the LHC has a mass of 126 GeV and SM-like branching ratios [1, 2]. The minimum of the function is achieved for a non-zero value of the invisible Higgs branching ratio, and the 1σ and 2σ values are given by χ2 = χ2min + ∆χ2, with ∆χ2 = 1, and 4 respectively With this prescription, we obtain BR(h0SM → inv) < 0.15(0.27) at 1σ(2σ), consistent with other recent analyses [61,62,63,64,65,66,67]. The RH neutrino mass increases with λN and so does the decay width Γh0SM →NN (see eq (2.10)) This gives rise to a vertical excluded area for S1 in the range 0.04 λN 0.09 which is independent of AλN. We have selected various representative benchmark points for each scenario, which are indicated in the plot by means of a yellow dot, labelled as S1a, S1b, S1c, S2a, S2b, and S2c, and with parameters defined at the bottom of table 1
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