Radiative decays of B mesons at LHCb

This thesis is dedicated to the study of radiative decays of B mesons at LHCb. At quark level, such decays are a b-sy transition and take place via a penguin loop and are sensitive to virtual contribution of New Physics, which can be indicated by an increase in the decay rates. These decays also offer the possibility to test the V-A structure of the Standard Model coupling in the processes mediated by loop penguin diagrams. In the decay Bs-ǿy, New Physics contribution can be probed by measuring the polarization of the photon in this decay. Systematic effects in the proper time reconstruction of the Bs in Bs-ǿy can bias the photon polarization measurement in this decay, which will reduce the sensitivity on the relevant New Physics parameter. The author studied those effects and developed ideas to calibrate them using Bd-K *y and Bs-J/ψǿ decays as control channels. These studies are mostly Monte Carlo based, due to a relatively small data set from the 2010 running. However, some studies and cross checks have indeed been performed with data. The author developed the trigger and stripping (another level of skimming the data, after the trigger) selections for Bs-ǿy and Bd-K*y decays, and made a major contribution to the selection of the first significant sample of Bd-K *y from the 2010 data set of LHCb

OPTIMIZATION OF PID CONTROLLER PARAMETERS USING ARTIFICIAL FISH SWARM ALGORITHM

This Final Year Project is preceded on the topic named “The Optimization of PID Control Parameters Using Artificial Fish Swarm Algorithm”. The background of the topic is presented in the Introduction chapter that describes on PID controllers. The Literature Review chapter thoroughly describes the Idea of Swarm Intelligence and Swarm Optimization. In methodology, the mathematical model of the algorithm is briefly described. For the Analysis and Discussion the PID Pressure Control Plant is used. Its simulation in MATLAB Simulink along with its block diagram is presented in the Results and discussions sections. The results found in the study shows that the optimization is valid and effective

Twists of Elliptic Curves

In this note we extend the theory of twists of elliptic curves as presented in various standard texts for characteristic not equal to two or three to the remaining characteristics. For this, we make explicit use of the correspondence between the twists and the Galois cohomology set $H^1\big(\operatorname{G}_{\overline{K}/K}, \operatorname{Aut}_{\overline{K}}(E)\big)$. The results are illustrated by examples

Learning Local Feature Aggregation Functions with Backpropagation

This paper introduces a family of local feature aggregation functions and a novel method to estimate their parameters, such that they generate optimal representations for classification (or any task that can be expressed as a cost function minimization problem). To achieve that, we compose the local feature aggregation function with the classifier cost function and we backpropagate the gradient of this cost function in order to update the local feature aggregation function parameters. Experiments on synthetic datasets indicate that our method discovers parameters that model the class-relevant information in addition to the local feature space. Further experiments on a variety of motion and visual descriptors, both on image and video datasets, show that our method outperforms other state-of-the-art local feature aggregation functions, such as Bag of Words, Fisher Vectors and VLAD, by a large margin.Comment: In Proceedings of the 25th European Signal Processing Conference (EUSIPCO 2017

Radiative Decays of B Hadrons at LHCb

LHCb is dedicated B physics experiment at the Large Hadron Collider (LHC) at CERN. The experiment aims to look for New Physics at energy scales much higher than those reachable through direct production, by measuring effects from the New Physics particles in rare beauty and charm decays. Radiative penguin decays of B mesons are an important part of the LHCb physics programme, and the detector is well positioned to harness the large statistics of these decays available at the LHC luminosity. Even with a small integrated luminosity of 100 pb$^{-1}$, 5% of what LHCb would collect in one nominal year of LHC, it can make a competitive measurement of the CP asymmetry in the decay $B_d \to K^*\gamma$