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Discovery prospects of a singly charged scalar at μTRISTAN

Joseph George1,2,*, Nobuchika Okada3,†, Dibyashree Sengupta4,5,‡, and Sudhir K. Vempati6,§

  • *Contact author: joseph.george@ncbj.gov.pl
  • †Contact author: okadan@ua.edu
  • ‡Contact author: sengupta.dibyashree@ucy.ac.cy
  • §Contact author: vempati@iisc.ac.in
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Phys. Rev. D 114, 035045 – Published 31 August, 2026

DOI: https://doi.org/10.1103/3d28-s1rs

Abstract

In this article, we study the associated production of a singly charged (Δ+) scalar along with a W+ boson in the newly proposed μ+μ+ collider (also known as μTRISTAN) at s=2  TeV. Such a singly charged scalar is naturally accommodated in an extremely well-motivated neutrino mass model, namely, the Type-II seesaw model. This model, besides providing a viable explanation of neutrino mass generation, also allows for lepton flavor violating (LFV) processes. Since LFV processes are not allowed in the standard model (SM), we focus on the discovery prospect of the singly charged scalar in the Type-II seesaw model at μTRISTAN through a LFV process, owing to the advantage of this process being free of any SM background. Additionally, this article also proposes a method to indicate if the underlying theory follows a normal or an inverted hierarchy depending on the distribution of lepton flavors in the final state.

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Phys. Rev. D 114, 035045– Published 31 August, 2026
  • Received 6 February 2026
  • Accepted 30 July 2026
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