DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS 2025

    • Thursday 18 September 2025 at 10:15 in A315 and using Zoom : Eva Guilloton (Warwick)
      Looking for BSM physics with H->tautau differential cross-section measurement at ATLAS
      Abstract: Detailed measurements of Higgs boson properties can be performed using its decays into fermions, providing in particular a key window into the nature of the Yukawa interactions. This talk will cover the results of the first unfold fiducial differential measurements of the Higgs boson cross-section in the Vector Boson Fusion phase space using a ditau decay mode, using the full Run 2 pp collision dataset collected at 13 TeV with the ATLAS detector. In these fiducial differential cross-section measurements, the Higgs boson cross section is considered as a function of different kinematic variables. These measurements depend minimally on theoretical models, making them a valuable point of comparison between experimental results looking at BSM physics. Four kinematics variables were choosen for their sensitivity to the kinematics and CP properties of VBF Higgs boson production, with the goal of validating the SM as well as providing sensitivity to BSM physics. The results are interpreted in the framework of the SM Effective Field Theory, which provides sensitivity to new physics beyond the reach of the current collider energies. This allows us to investigate for effects from CP violation in the VBF Higgs boson production mode.
    • 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: TBA

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],
Jaakko Annala (jaakko annala at helsinki fi) [cosmo seminar]

New Nordic series of seminars over the web, link: https://sites.google.com/view/nordictheory/home
For more information, and to subscribe to email announcements, contact Oscar Henriksson (oscar henriksson at helsinki fi)

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