2026/07/16 by Mariana Frank, Benjamin Fuks, Chayan Majumdar +1
#hep-ph
We investigate the sensitivity of a same-sign μ+μ+ collider to doubly charged scalars in the Type-II seesaw framework, focusing on the regime in which the doubly charged scalar decays dominantly into same-sign W-boson pairs. Motivated by the μTRISTAN proposal, for a benchmark we consider a degenerate triplet spectrum at a center-of-mass energy of 2~\rm TeV and an integrated luminosity of 1~\rm ab-1. The signal process is studied in the fully hadronic W-decay mode, leading to a characteristic μ+μ+ + 8j final state. We develop a cut-based analysis based on high jet multiplicity and global hadronic W reconstruction, and then improve its sensitivity with a multivariate strategy exploiting reconstructed W observables, global event kinematics, multi-boson variables and spectator-muon information. The best-performing setup reaches a 2σ sensitivity level for doubly charged scalar masses up to 425-430~\rm GeV, extending the cut-based reach by a few tens of GeV. This indicates an improvement over the current LHC coverage, while also providing an independent probe based on a qualitatively different production mode and collider environment.