The effects of metallicity on convective overshoot behaviour in models of (delta) Scuti stars

Delta Scuti variables are stars which exhibit periodic changes in their luminosity through radial and non-radial pulsations of their surfaces. The aim of this research is to gain a better understanding of those stars' behaviours through an expansion of the findings of Lovekin and Guzik, which found a strong correlation between Delta Scuti stars' pulsation constant (Q) as a function of effective temperature and the amount of convective overshoot within the star. However, only models with metallicities of Z = 0.02 were examined, prompting the question of if this relation is dependent on chemical composition. I collected the data in this research through creation of a grid of stellar models using the open-source coding language MESA, and analyzed the models pulsation properties using the complementary coding language GYRE. By varying the models mass, rotation speed, convective overshoot, and metallicity it was determined that the relationship found by Lovekin and Guzik does hold for stars of other metal compositions and may have a quantifiable metallicity dependence, although statistically weak. In addition, a second relation between Q as a function of effective temperature and convective overshoot was discovered at higher effective temperatures as well. The cause of this new relation was found to be due to the deepest surface convection zone depth of the models

Neutron scalar polarizabilities

The known values for the scalar polarizabilities of the neutron have a relatively large experimental error compared to that of the proton. Previously these values were found by analyzing the results of Compton scattering with a deuterium target, but this method has many causes for uncertainty. The A2 collaboration at the Institut fur Kernphysik at Johannes Gutenberg Universitat in Mainz, Germany, plans to measure the neutron polarizabilities in a new way. Now, similar Compton scattering based experiments will be carried out with a new active target filled with high-pressure 3He gas. This active target will allow previously unmeasured quantities of the reaction to be analyzed, thus reducing the background noise of the data, and therefore lowering the experimental error. But to do this software has to be used to reconstruct the events within the active target. The new active target and the software used to reconstruct it are still in development; in particular, I will be aiding in the development of the software

The search for new physics signals in observables of rare dileptonic Bs Meson Decays using AdS/QCD correspondence and QCD SR models

The main goal of this theoretical research project aimed to predict decay observables for the rare dileptonic process Bs --> φµ+µ-. Specifically, the differential branching ratio was computed using both QCDSR and AdS/QCD methods. Emphasis was placed on the latter method in order to probe and investigate the model dependence of the theoretical predictions of rare B decays, which are essential in search of New Physics beyond the Standard Model. Our preliminary results indicate that the discrepancies between the experimental results and the AdS/QCD correspondence model predictions are lower than those from the QCD Sum Rules, which are often referred to as the SM predictions. The effects of higher twist distribution amplitudes on the differential branching ratio B --> K*νν of were also investigated