0000000000169798
AUTHOR
Mehran Zahiri Abyaneh
Some aspects of Chiral Perturbation Theory and Neutrino Physics
En la primera parte de la tesis hemos trabajado en la física de ChPT. Debido al hecho de que los quarks y los gluones están confinados en el interior de los hadrones, son los hadrones los grados de libertad asintóticos que se observan en la física macroscópica. Por lo tanto, los estados inicial y final en nuestros experimentos de bajas energías no van a ser quarks y gluones sino hadrones sin carga de color. Todavía no se sabe una transformacion del lagrangiano de QCD y sus pará- metros y las propiedades de los hadrones. Un método ampliamente utilizado de afrontar el problema ha sido a través de teorías efectivas. En el caso de QCD, se llama ChPT. Como ChPT es la teoría efectiva de QCD, su l…
High scale mixing relations as a natural explanation for large neutrino mixing
The origin of small mixing among the quarks and a large mixing among the neutrinos has been an open question in particle physics. In order to answer this question, we postulate general relations among the quarks and the leptonic mixing angles at a high scale, which could be the scale of Grand Unified Theories. The central idea of these relations is that the quark and the leptonic mixing angles can be unified at some high scale either due to some quark-lepton symmetry or some other underlying mechanism and as a consequence, the mixing angles of the leptonic sector are proportional to that of the quark sector. We investigate the phenomenology of the possible relations where the leptonic mixin…
Precise predictions for Dirac neutrino mixing
The neutrino mixing parameters are thoroughly studied using renormalization-group evolution of Dirac neutrinos with recently proposed parametrization of the neutrino mixing angles referred as `high-scale mixing relations'. The correlations among all neutrino mixing and $CP$ violating observables are investigated. The predictions for the neutrino mixing angle $\theta_{23}$ are precise, and could be easily tested by ongoing and future experiments. We observe that the high scale mixing unification hypothesis is incompatible with Dirac neutrinos due to updated experimental data.