DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS 2025

• • Tuesday 23 September 2025 at 10:15 in A315 and using Zoom : Charles Lewis (Seattle)
    Search for Resonant and Non-resonant Higgs Boson Pair Production in the bbbb Final State
    Abstract:In the Standard Model, the production of a pair of Higgs bosons provides direct sensitivity to the Higgs self-coupling and probes the structure of the Higgs potential. Extensions of the Standard Model can also predict new scalar resonances that can decay into a pair of scalar bosons. This seminar presents ATLAS searches for Higgs boson pair production in the fully hadronic bbbb final state, using proton–proton collision data from LHC Run 2 at 13 TeV and early Run 3 at 13.6 TeV. Non-resonant analyses explore both the Standard Model production mechanism and variations in the Higgs trilinear coupling, while resonant searches encompass scenarios with heavy new particles decaying into Standard Model Higgs bosons or additional Higgs-like scalars. Together, these studies provide a comprehensive picture of Higgs boson pair production and its sensitivity to new physics.
  • Thursday 25 September 2025 at 10:15 in A315 and using Zoom : Theodoros Chatzistavrou (Athens)
     Studying Jet Triggers and Single Top Quark Mass with the CMS experiment
    Abstract: This seminar presents two topics which are conducted with the CMS experiment at the LHC. The first part focuses on jet and missing transverse energy (MET) based triggers, for efficiently selecting events of interest in the high-rate environment of the LHC. We discuss how these triggers operate, the reconstruction of the objects and their performance, as well as the impacts in physics. Attention is also given to their potential for improvement and evolution toward the Phase-2 CMS upgrade, where the higher luminosity will be even more challenging for hadronic physics objects in such dense environments. The second part of the seminar addresses the measurement of the top quark mass, a fundamental parameter of the Standard Model, using events from single top quark production. Unlike the dominant top–antitop pair production, the single top process provides complementary measurements, offering an alternative approach to precision mass determination. Together, these studies highlight both the technical challenges of data collection at the trigger level and the ongoing efforts to refine key measurements of the Standard Model at the energy frontier.

Hopefully the up to 50 min + 10 min discussion long seminar/colloquium will be understandable to a wide audience.
Contacts: Keijo Kajantie (keijo kajantie at helsinki fi) [ HIP seminar],
Tushar Gupta  (tushar.gupta at helsinki fi) [cosmo seminar]

Other related seminars

Friday 10-12 seminar series in D114:Astrophysics seminar
Mathematical Physics Seminar and Workshop series Wed 14-16 in Exactum C123.
InstituteQ Events and Seminars