Hon.-Prof. Allen C. Caldwell

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Analyse der Flavour-Amplituden in B - K π-Zerfällen

B-Mesons can decay into 4 isospin variants of Kπ pairs. Different combinations of decay processes (tree, colour suppressed tree, penguin, etc) contribute to the decay amplitudes of these decays. Based on the measured branching fractions and CP-violation ratios it is possible to disentangle the magnitude of the various contributions and their relative phases. This allows to constrain theoretical models and even to give hints of deviations from the standard model. In this work the theoretical models should be fitted to the data, checking for inconsistencies and making prediction on what quantities need to be measured in future.

suitable as

• Bachelor’s Thesis Physics

Supervisor: Allen C. Caldwell

Anpassung von mehreren Scheitelpunkten mit RAVE

B-Mesons mainly decay in a B->D chain. Since the D decay vertex is displaced from the B decay vertex the determination of the B vertex gets biased if tracks from the D decay are included in the fit. The RAVE package allows in principle to fit multiple vertices and hence separate tracks from B and D decays. It should be studied if this feature can be used to improve the vertex resolution.

suitable as

• Bachelor’s Thesis Physics

Supervisor: Allen C. Caldwell

Die Valenzstruktur des Protons

The Bayesian Analysis Toolkit will be used in conjunction with QCDNUM, a package to solve the integro-differential equations describing the evolution of the proton structure with different resolution scales to analyze the recently published 'high-x data' on the proton structure from the ZEUS Collaboration.  The goal is to extract the distributions of quarks and gluons in the proton and their uncertainties at the highes values of x, the momentum fraction carried by these partons.  The project will be carried out with support from experts in Data Science and experts on proton structure studies.

suitable as

• Master’s Thesis Nuclear, Particle, and Astrophysics

Supervisor: Allen C. Caldwell

Optimierung der Anpassungsverfahren zur Bestimmung von ΔΓ in B0d-Zerfällen.

Find the best strategy to measure the width difference ΔΓ between even and odd CP eigenstates of the B0d comparing various analyses methods, e.g. : Two component fit, weighting, moments, multi-parameter log-likelihood fit, etc.

suitable as

• Bachelor’s Thesis Physics

Supervisor: Allen C. Caldwell

Strategie für den Umgang mit Mehrfachbewerbern

In a typical analysis at the Belle II experiment (and of course in many other experiments) B decays are reconstructed by combining different reconstructed tracks and selection combinations which best fit the decay type search for. Often more than one combination which fits the selction criteria is found in a single event. There are different strategies to deal with such multiple candidates: using all equally, selecting ‘best candidate’ using additional criteria, ignoring such events, and multi-dimensional fits. Using Monte Carlo studies the advantages and disadvantages of these strategies should be investigated: Do they introduce a bias, do they make optimal use of the available statistics and what kind of systematic uncertainties might arise.

suitable as

• Bachelor’s Thesis Physics

Supervisor: Allen C. Caldwell

Überwachung und Analyse von Leistungsänderungen des PXD-Detektors während eines Laufs.

During a run the silicon sensors of the PXD (Pixel vertex detector) suffer from radiation damage which leads to gain changes or even to fatal damages of a pixels. From existing data the PXD properties needs to be extracted and changes should be correlated with the performance of the accelerator.

suitable as

• Bachelor’s Thesis Physics

Supervisor: Allen C. Caldwell