Mgr. Peter Maták, PhD.
Katedra teoretickej fyziky FMFI UK
Mlynská dolina, 84248 Bratislava
F2-145, ☏ +421 (0)2 602 95 460, peter.matak(at)fmph.uniba.sk, rozvrh
Konzultačné hodiny - kedykoľvek po predchádzajúcom dohovore.
Úlohou tohto predmetu je sprostredkovanie prvého kontaktu so špeciálnou teóriou relativity. Predmet je vhodný pre druhý a tretí ročník bakalárskeho štúdia. Hodnotenie uzavrieme na základe písomky na konci semestra.
Parametric Dependence of the Boltzmann Equation for Asymmetry Production via Freeze-in and Freeze-out
One of the open questions in both particle physics and cosmology is the origin of the baryon asymmetry of the universe. Many models of baryogenesis rely on simple extensions of the Standard Model in which particle couplings carry new complex phases, leading to CP-violating interactions, one of the Sakharov conditions. The Boltzmann equation for the density asymmetry of a given particle species contains two terms. The source term depends on the asymmetries of reaction rates, while the wash-out term is proportional to their symmetric part multiplied by the density asymmetry. These two terms, however, typically depend on the same set of couplings and are therefore correlated. The required departure from thermal equilibrium can be realized, for example, through freeze-in or freeze-out mechanisms. In this thesis, we explore the parametric dependence of the Boltzmann equation for asymmetric freeze-in and freeze-out, considering the dependence on both the couplings and the overall temperature scale.
Departure from Thermal Equilibrium Before and During Freeze-out of a Thermal Relic in the Early Universe.
For models of baryogenesis, departure from thermal equilibrium is one of the well-known Sakharov conditions. In the Boltzmann equation for the generation of the matter-antimatter asymmetry, two terms compete. The source term generates the asymmetry through the rates of asymmetric reactions involving out-of-equilibrium particles, while the wash-out term erases it. The former is typically proportional to the difference between the density of a given species and its equilibrium value. This proportionality factor will be studied in this thesis for temperatures above the freeze-out temperature, which is set by the particle mass scale. Different reaction topologies will be explored. Semi-analytical solutions and approximations will be compared with numerical solutions.
Blažek, T., Maták, P., Ramaj, J., Sabová, M. (2025), Minimal effective theory for leptogenesis, dark matter, and neutrino masses, https://link.springer.com/article/10.1140/epjc/s10052-025-14543-w
Blažek, T., Maták, P., Zaujec, V. (2025), Asymmetric dark matter from semi-annihilation: unitarity constraints and long-lived final states, https://link.springer.com/article/10.1007/JHEP04(2025)104
Aghaie, M., Armando, G., Conaci, A., Dondarini, A., Maták, P., Panci, P., Šinská, Z., Ziegler, R. (2024), Axion dark matter from heavy quarks, https://doi.org/10.1016/j.physletb.2024.138923
Blažek, T., Heeck, J., Heisig, J., Maták, P., Zaujec, V. (2024), Dirac leptogenesis from asymmetry wash-in via scatterings, https://link.aps.org/doi/10.1103/PhysRevD.110.055042
Maták, P. (2024), Unitarity, real-intermediate states, and fixed-order approach to resonant dark matter annihilation, https://doi.org/10.1103/PhysRevD.109.043008
Blažek, T., Maták, P., Zaujec, V. (2022), Mass-derivative relations and unitarity constraints for CP asymmetries at finite temperature, https://doi.org/10.1088/1475-7516/2022/10/042
Maták, P. (2022), Modifying the Dyson series for unstable particles and resonances, https://doi.org/10.1103/PhysRevD.105.076019
Blažek, T., Maták, P. (2022), Mass-derivative relations for leptogenesis, https://doi.org/10.1140/epjc/s10052-022-10165-8
Blažek, T., Maták, P. (2021), Cutting rules on a cylinder: a simplified diagrammatic approach to quantum kinetic theory, https://doi.org/10.1140/epjc/s10052-021-09874-3
Blažek, T., Maták, P. (2021), CP asymmetries and higher-order unitarity relations, https://doi.org/10.1103/PhysRevD.103.L091302
A complete list of publications can be found here.