magistrsko delo
Luka Jevšenak (Author), Nejc Košnik (Mentor)

Abstract

Začnemo s pregledom diskretnih simetrij standardnega modela osnovnih delcev. Pri tem se posebej posvetimo simetriji CP. Pokažemo vpliv kršitve CP na nastanek barionske asimetrije v našem vesolju in s tem motiviramo iskanje kršitve CP zunaj standardnega modela. Eksperimentalne meritve razpadov mezonov B nakazujejo na novo fiziko, v semileptonskih razpadih kvarkov b na kvarke c. V efektivni Lagrangian interakciji razpada kvarka b lahko dodamo dva člena dimenzije šest, ki sklapljata kvarka b in c z leptonoma $\tau$ in $\nu_\tau$. S tem dobimo dve interakciji nove fizike s sklopitvenima konstantama $g_T$ in $g_S$, ki sta v splošnem kompleksni in kršita simetrijo CP. Zaradi študije sklopitev $g_S$ in $g_T$ na hadronskem trkalnuku sestavimo opazljivke $\Delta\omega$ na partonskem nivoju za proces sipanja protonov na kvark b, kvark c in par leptonov $\tau$ in $\nu_\tau$. Te opazljivke so senzitivne na kompleksno fazo med sklopitvama $g_S$ in $g_T$. Za vrednosti $g_S$ in $g_T$, ki jih dovoljuje $R_{D^{(*)}}$, napovemo $\Delta\omega$ in statistično signifikanco za prihodnje zagone LHC.

Keywords

fizika osnovnih delcev;razširitve Standardnega modela;fizika okusov;kršitev simetrije CP;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL FMF - Faculty of Mathematics and Physics
Publisher: [L. Jevšenak]
UDC: 539.120
COBISS: 162979843 Link will open in a new window
Views: 11
Downloads: 4
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Search for CP-odd phases in semileptonic processes at hadron colliders
Secondary abstract: We start by reviewing the discrete symmetries of the Standard model, focusing on CP symmetry more specifically. We show that CP symmetry violation is an essential component to create the baryon asymmetry in universe as we see today. That is the motivation to search for CP symmetry violation in physics beyond the Standard model. Experimental measures of B mesons hint of new physics in semileptonic decay of b quarks to c quarks. We propose two new dimension six operators in the $\tau$ lepton flavor sector. With this we get two new interactions with couplings $g_S$ and $g_T$. These two coupling constants are complex in general and thus violate the CP symmetry. In order to probe the two coupling constants on a proton collider we construct angular observables $\Delta\omega$ at parton level of proton collision process, that produces quarks b and c and leptons $\tau$ and $\nu_\tau$. These observables are sensitive to the relative complex phase between the two coupling constants. Using the allowed region in $g_S$ $g_T$ parameter space, we predict $\Delta \omega$ and its statistical significance that would be observed in future LHC runs.
Secondary keywords: physics of elementary particles;Standard model extensions;flavor physics;CP violation;
Type (COBISS): Master's thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za matematiko in fiziko, Oddelek za fiziko
Pages: 52 str.
ID: 19876338