1993/10/18 by Marc Sher, Sher, Marc
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Neutrino Physics Research #Particle Accelerators and Free-Electron Lasers #Particle accelerators and beam dynamics #hep-ph
paper · pdf · doi:10.48550/arxiv.hep-ph/9310305
(talk presented at the 16th Kazimierz Meeting, Poland, May 1993), 4 pages, no figures, Phyzzx (macros appended at beginning), WM-93-111
arxiv created 1993/10/18 · openalex publication_date 1993/10/18 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Very little is known about the mass spectrum of fermions in the standard model. In this talk, I point out that in the simplest extension of the standard model, in which all right-handed fields are singlets, it is quite possible that a fourth-generation neutrino will be heavier that its charged counterpart. The latter will then be very long-lived. Three plausible values of the mixing angle give very different phenomenology; the charged lepton will either decay at the vertex (albeit into a massless neutrino), away from the vertex but within the detector, or will pass completely through the detector. In the latter case, then if the detectors at the LHC and SSC have the ability to determine the velocity of these particles, they will look just like muons and be missed. In the extreme case in which the mixing angle is only generated by Planck scale effects (it can't be zero for cosmological reasons), not only is detection possible, but collection for further study may be possible. Finally, in an alternative model in which the fourth generation leptons form an isodoublet, the possible decay of the charged lepton into τZ offers a promising, nearly background free, method of detection.