BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Pedro Ferreira (ISEL and CFTC-UL\, Lisbon\, Portugal) DTSTART:20210201T150000Z DTEND:20210201T160000Z DTSTAMP:20260423T003248Z UID:IFTWeb/31 DESCRIPTION:Title: Multiscalar models - theoretical puzzles and LHC searches\nby Pedro Fe rreira (ISEL and CFTC-UL\, Lisbon\, Portugal) as part of IFT-Madrid Webina rs\n\n\nAbstract\nThe Standard model contains a single elementary scalar p article\, the Higgs boson\, discovered at the LHC in 2012. The Model is re markably successful\, but it leaves a great deal of unanswered questions. There have been many attempts to addressed some of those open issues\, by enlarging the scalar sector\, thus predicting a richer spectrum of spin-0 elementary particles. This allows one to create models where one may: have Dark Matter candidates complying with all current experiemental constrain ts\; predict spontaneous (or explicit) CP violation arising from the scala r sector\; or explain eventual excesses in LHC search channels.\n\nA large r scalar spectrum\, however\, raises problems of its own: the size of the parameter space increases\, with potentially a large number of parameters with unknown values and ranges reducing the model's predictivity. The vacu um state of the theory is no longer guaranteed\, in many multiscalar model s\, to lead to the correct electroweak symmetry breaking. Tree-level flavo ur changing neutral currents (FCNC) mediated by neutral scalars are on man y occasions possible\, the magnitude of those couplings heavily restricted by existing experimental data.\n\nIn this seminar I'll review the basic c onstraints one needs to ask of multiscalar models to be certain it is a vi able model\; and the "tools of the trade" to help when one is creating a m odel with specific purposes. I'll also show several recent results discus sing vacuum stability in several multiscalar models\; a simple solution to the strong-CP problem\; constraints on multiscalar parameter space from d ark matter searches\; and exotic sources of CP violation.\n LOCATION:https://researchseminars.org/talk/IFTWeb/31/ END:VEVENT END:VCALENDAR