DEPARTMENT OF PHYSICS / HIP JOINT COLLOQUIA / SEMINARS 2026

• • Tuesday 20 October 2026 at 10:15 in A315 and using Zoom: Matti Heikinheimo (Helsinki)
    The LZ high energy recoil event and possible dark matter explanations for it
    Abstract: The Lux-Zeplin experiment has observed a single event in a high recoil energy search, with characteristics matching a nuclear recoil of 248 keV. Such an event is not expected from any known backgrounds. I will discuss some dark matter models proposed in the literature that could explain the observation while avoiding a large number of expected events in the low energy region, where none are observed. Among those is light dark matter that interacts with the SM via spin and momentum dependent interactions, where the high energy recoil is due to a high velocity component of the DM flux, arising via scattering with energetic cosmic rays.
  • Thursday 22 October 2026 at 10:15 in A315 and using Zoom: Roman Zwicky (Edinburgh)
    QCD, Dilaton and Infrared Fixed Points
    Abstract: The possibility that QCD, or a chirally broken phase of a gauge theory, admits an infrared fixed point interpretation is explored. I will first review the conformal window and show that the assumptions lead to a consistent picture, including N=1 supersymmetric gauge theories and determine scaling dimension by matching QCD operators with the effective theory. In a second part I will talk about dilaton properties in view of soft theorems perspective as well as an exactly solvable three-dimensional model. In the last part I speculate that the sigma meson could be a dilaton and give an outlook on the Higgs as a dilaton.
  • Tuesday 27 October 2026 at 10:15 in A315 and using Zoom: Débora Mroczek (Turku)
    TBA
    Abstract: TBA
  • Thursday 29 October 2026 at 10:15 in A315 and using Zoom: Guilherme Catumba (Milano)
    The non-perturbative matching of Magnetostatic QCD
    Abstract: High-temperature QCD can be described, through dimensional reduction, by a series of 3D effective field theories. Electrostatic QCD consists of a gauged-scalar theory, while magnetostatic QCD (MQCD) is a pure 3D gauge theory. The use of dimensionally reduced effective theories to predict 4D observables relies on the matching between the 3D and 4D theories, which, at present, is only known perturbatively.  We have devised a strategy to perform a fully non-perturbative matching of QCD  and MQCD via lattice simulations.  This allows us to assess the accuracy and validity  of the effective theory without perturbative uncertainties coming from the matching.  In this talk I will explain how the matching is performed over a wide range of temperatures with high precision, while keeping all lattice systematics under control. As a first step in this study, we investigate the matching between the finite temperature pure gauge theory and its 3D counterpart, for which I report some results.
    
  • Tuesday 3 November 2026 at 10:15 in A315 and using Zoom: Antti Hippeläinen (Helsinki)
    Probing hadronic structure with holographic methods
    Abstract: Gravitational form factors encode how mass, spin and internal forces are distributed inside hadrons, and they remain challenging to access. We discuss how holographic models of QCD offer a complementary route and present results obtained in improved holographic QCD and V-QCD for the proton, the pion, rho and a_1 mesons and glueballs. For mesons, the form factors are parameter-free predictions of the model. We close by discussing where the holographic description can be expected to be reliable, and what spin-1 states show about the limits of the mechanical interpretation.

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