Department of Theoretical Physics

[HEP seminar] Nudžeim Selimović: Lepton-Quark Fusion at Hadron Colliders, precisely
2021-03-18 10:15 - 11:00 (Europe/Ljubljana) | Zoom
The collider phenomenology of TeV-scale leptoquarks had a new twist recently. The precise extraction of lepton parton distribution functions based on the LUX method facilitated an additional leptoquark production mechanism, the resonant leptoquark production. After briefly reviewing and comparing different production mechanisms, I will present the first computation of next-to-leading order QCD and QED corrections to the resonant leptoquark production cross-section at the Large Hadron Collider. Various NLO K-factors, together with the theoretical uncertainties due to the renormalisation and factorisation scale variations and the limited knowledge of parton distribution functions will be shown. I will conclude with a discussion of the possibility to disentangle the flavor structure of leptoquark interactions by exploiting the interplay between different production channels.
Join at: https://zoom.us/j/3601731049?pwd=[REDACTED]

[Biophysics seminar]: Prof. Aykut Erbas (Bilkent University, Ankara) - "Insights for Molecular self-assembly from computer simulations "
2021-03-12 13:00 - 15:00 | Zoom
Meeting ID: 990 5563 4981
Passcode: bio

[HEP Seminar] Florian Goertz: Dark Matter and Baryogenesis with an Inert Doublet
2021-03-04 14:00 - 15:00 | Zoom
In this talk, we discuss the prospects to realize Dark Matter (DM) in the Inert Doublet Model, while simultaneously enhancing the Electroweak Phase Transition (EWPhT) such as to induce electroweak baryogenesis. To this end, we analyze the nature of the EWPhT in both light and heavy DM regions, and explore a viable region where a non-trivial two-step EWPhT can appear, allowing for the correct relic abundance and agreement with direct-detection bounds. Finally, we discuss a new region for light DM with a small mass splitting, lifting the usual assumption of exact degeneracy of the new non-DM scalars, and comment on possibilities to implement enough CP violation to fulfill the Sakharov Conditions.

PhD thesis defense: Urša Skerbiš Štok Title: Scattering of particles with spin in lattice QCD
2021-03-02 16:00 - 17:00 | Zoom
Title: Scattering of particles with spin in lattice QCD.
https://uni-lj-si.zoom.us/j/3306242511
Meeting ID: 330 624 2511
https://www.fmf.uni-lj.si/sl/obvestila/dogodek/70/zagovor-doktorata-ursa-skerbis-stok-sipanje-delcev-s-spinom-v-kromodinamiki-na-mrezi/

[HEP-seminar] Svjetlana Fajfer: Coloured Scalar Mediated Decays to Invisible Fermions
2021-02-11 10:15 - 11:00
https://fmf-uni-lj-si.zoom.us/j/3601731049?pwd=[REDACTED]

[HEP-seminar] Nejc Košnik / Leptoquarks and Real Singlets: A Richer Scalar Sector Behind the Origin of Dark Matter
2021-01-14 10:00 - 11:00 | Zoom
We investigate scenarios with O(1TeV) scalar leptoquarks that act as portals between the Standard Model and Dark Matter. We assume that Dark Matter is a scalar singlet S which couples to a scalar leptoquark Δ and the Higgs boson via the terms in the scalar potential. In addition, the leptoquark is endowed with Yukawa couplings to quarks and leptons that may address the anomalies in B meson decays. We consider the SS annihilation cross sections to estimate the Dark Matter relic abundance and explore the interplay between astrophysical, collider and flavour physics bounds on such models. In the heavy Dark Matter window, mS>mΔ, the leptoquark portal becomes the dominant mechanism to explain the Dark Matter abundance. We find that the leptoquark Yukawa couplings, relevant for quark and lepton flavour physics, are decoupled from the dark matter phenomenology. By focussing on a scenario with a single leptoquark state, we find that relic density can only be explained when both Δ and S masses are lighter than O(10TeV).
Via zoom: https://fmf-uni-lj-si.zoom.us/j/3601731049?pwd=[REDACTED]
Material available via Indico.

[Biophysics seminar] Uroš Tkalec: Stimuli-responsive liquid crystal interfaces
2020-10-16 13:00 - 14:00 | Zoom

[High Energy Physics Seminars] Admir Greljo: The Neutrino Magnetic Moment Portal: Cosmology, Astrophysics, and Direct Detection
2020-10-15 10:15 - 11:15 | Zoom
Via zoom https://zoom.us/j/3601731049
We revisit the physics of neutrino magnetic moments, focusing in particular on the case where the right-handed, or sterile, neutrinos are heavier (up to several MeV) than the left-handed Standard Model neutrinos. The discussion is centered around the idea of detecting an upscattering event mediated by a transition magnetic moment in a neutrino or dark matter experiment. Considering neutrinos from all known sources, as well as including all available data from XENON1T and Borexino, we derive the strongest up-to-date exclusion limits on the active-to-sterile neutrino transition magnetic moment. We then study complementary constraints from astrophysics and cosmology, performing, in particular, a thorough analysis of BBN. We find that these data sets scrutinize most of the relevant parameter space. Explaining the XENON1T excess with transition magnetic moments is marginally possible if conservative assumptions are adopted regarding the supernova 1987A and CMB constraints. Finally, we discuss model-building challenges that arise in scenarios that feature large magnetic moments while keeping neutrino masses well below 1 eV. We present a successful ultraviolet-complete model of this type based on TeV-scale leptoquarks, establishing links with muon magnetic moment, B physics anomalies, and collider searches at the LHC.
https://zoom.us/j/3601731049

[F1 department seminar] Matej Krajnc: Shape, function, and dynamics of biological tissues
2020-10-09 13:00 - 14:00 | Seminarska soba fizike (106), Jozef Stefan Institute (Jamova 39), Ljubljana

[High Energy Physics Seminars] Raffaele-Tito D'Agnolo: Crunching Dilaton, Hidden Naturalness
2020-10-08 10:15 - 11:00 | Zoom
https://zoom.us/j/3601731049
We introduce a new approach to the Higgs naturalness problem, where the value of the Higgs mass is tied to cosmic stability and the possibility of a large observable Universe. The Higgs mixes with the dilaton of a CFT sector whose true ground state has a large negative vacuum energy. If the Higgs VEV is non-zero and below O(TeV), the CFT also admits a second metastable vacuum, where the expansion history of the Universe is conventional. As a result, only Hubble patches with unnaturally small values of the Higgs mass support inflation and post-inflationary expansion, while all other patches rapidly crunch. The elementary Higgs VEV driving the dilaton potential is the essence of our new solution to the hierarchy problem. The main experimental prediction is a light dilaton field in the 0.1-10 GeV range that mixes with the Higgs. Part of the viable parameter space has already been probed by measurements of rare B-meson decays, and the rest will be fully explored by future collide rs and experiments searching for light, weakly-coupled particles.

[Biophysics Seminar] Fabio Staniscia: Adsorption at the nanoscale
2020-10-02 13:00 - 14:00

Bioseminar by Iztok Urbančič: Advanced optical methods enlighten molecular interactions within live cells
2020-09-22 13:00 - 14:00 | Zoom
Advances in understanding of complex biological systems crucially depend on the development of biophysical methods, such as super-resolution fluorescence microscopies and spectroscopies, which provide detailed information on structure and dynamics at the molecular level. We develop such advanced optical techniques and use cell-mimicking model systems to better understand the processes within living cells. In the seminar, I will present our recent investigations of molecular organisation within biological membranes, in particular the biophysical interplay between lipids and proteins involved in the activation of T lymphocytes – the key step of our immune response.

Matej Krajnc: Deep cell graphs (Bioseminar)
2020-09-03 13:00 - 14:00 | Zoom

Seminar: Marin Šako, Reconstruction of the Angular Distribution of Nuclear Reactions
2020-06-18 14:00 - 15:00 | F1 tearoom

BioSeminar: Jan Rozman
2020-06-05
I will represent my Princeton paper, which we will submit soon.

BioSeminar: Primož Ziherl
2020-05-21 10:00 - 11:00
I will talk about quasicristals and the concept of the sliver mean. The seminar will be via Zoom.

BioSeminar: Clement Zankoc
2020-05-01

Seminar: Matej Krajnc
2020-01-28 10:00 - 11:00
In this talk I will present how to write a reply letter to referees.

Testni event
2020-01-24

Aleks Smolkovič: JC, Precise Relic WIMP Abundance and its Impact on Searches for Dark Matter Annihilation
2019-12-12 11:00 - 12:00
Gary Steigman, Basudeb Dasgupta, John F. Beacom: Precise Relic WIMP Abundance and its Impact on Searches for Dark Matter Annihilation
https://arxiv.org/abs/1204.3622

Demo dogodek
2019-12-11
