Long-lived bi$\boldsymbol{\nu}$o at the LHC

TL;DR

This paper explores the detection prospects of a long-lived biνo, a pseudo-Dirac bino linked to neutrino masses, at the LHC and specialized long-lived particle detectors, highlighting potential for discovering new physics in extended supersymmetric models.

Contribution

It provides the first analysis of long-lived biνo detection at LHC and dedicated detectors, mapping out the parameter space and experimental reach for this new particle.

Findings

Large parameter space can be probed by MATHUSLA.

Biνo masses from 10 GeV to 2 TeV are detectable.

Significant regions of squark-biνo-messenger scale space are accessible.

Abstract

We examine the detection prospects for a long-lived bi$\nu$o, a pseudo-Dirac bino which is responsible for neutrino masses, at the LHC and at dedicated long-lived particle detectors. The bi$\nu$o arises in $U(1)_R$-symmetric supersymmetric models where the neutrino masses are generated through higher dimensional operators in an inverse seesaw mechanism. At the LHC the bi$\nu$o is produced through squark decays and it subsequently decays to quarks, charged leptons and missing energy via its mixing with the Standard Model neutrinos. We consider long-lived bi$\nu$os which escape the ATLAS or CMS detectors as missing energy and decay to charged leptons inside the proposed long-lived particle detectors FASER, CODEX-b, and MATHUSLA. We find the currently allowed region in the squark-bi$\nu$o mass parameter space by recasting most recent LHC searches for jets+MET. We also determine the reach of MATHUSLA, CODEX-b and FASER. We find that a large region of parameter space involving squark masses, bi$\nu$o mass and the messenger scale can be probed with MATHUSLA, ranging from bi$\nu$o masses of 10 GeV-2 TeV and messenger scales $10^{2-11}$ TeV for a range of squark masses.