Studium produkce dijetů v difračních interakcích na HERA

Tématem práce je měření účinného průřezu difrakční produkce dijetů v pozitron-protonových interakcích za použití detektoru H1 na urychlovači HERA. Difrakční interakce e+p → e+Xp jsou měřeny při těžiš`tové energii 319 GeV, systém X obsahuje nejméně dva jety a proton je detekován v H1 spektrometru VFPS. Měření je realizováno ve fotoprodukčním režimu definovaném virtualitou fotonu Q2 < 2 GeV2 a v hlubokém nepružném rozptylu s 4 GeV2 < Q2 < 80 GeV2 . Výsledky jsou srovnány s QCD výpočty vyššího řádu založenými na difrakčních partonových distribučních funkcích získaných z měření inkluzivního účinného přůřezu v difrakčním hluboce nepružném rozptylu. Platnost kolineární QCD faktorizace je testována s využitím naměřených účinných průřezů a jejich poměrů. 1The cross section of the diffractive process e+p → e+Xp is measured at a centre-of-mass energies of 319 GeV, where the system X contains at least two jets and the leading final state proton p is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction defined by photon virtualities Q2 < 2 GeV2 and in deep-inelastic scattering with 4 GeV2 < Q2 < 80 GeV2 . The results are compared to next-to-leading order QCD calculations based on diffractive parton distribution functions as extracted from measurements of inclusive cross sections in diffractive deep- inelastic scattering. A collinear QCD factorization theorem is tested against the measured cross sections and their ratios. 1Ústav částicové a jaderné fyzikyInstitute of Particle and Nuclear PhysicsMatematicko-fyzikální fakultaFaculty of Mathematics and Physic

Feebly Interacting Particles: FIPs 2022 workshop report

Particle physics today faces the challenge of explaining the mystery of dark matter, the origin of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent fine-tuning of the electro-weak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to familiar matter, below the GeV-scale, or even radically below, down to sub-eV scales, and with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and indeed, existing data provide numerous hints for such possibility. A vibrant experimental program to discover such physics is under way, guided by a systematic theoretical approach firmly grounded on the underlying principles of the Standard Model. This document represents the report of the FIPs 2022 workshop, held at CERN between the 17 and 21 October 2022 and aims to give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs