Model agnostic angular analysis of semitauonic decays with LHCb data

One of the most intriguing results to come out of the era of the B-factories is the unexpectedly large branching fraction of semitauonic B decays. An similarly enhanced branching fraction is also seen the the LHCb Run 1 data and the global average currently lies 3.8 sigma from the standard model expectation. At LHCb, parallel analyses have been published using Run 1 data in both the case where the tau decays to a muon and where it is reconstructed in a three pion decay mode (plus neutrinos). The challenge now is to improve the analysis of such B decays using the complete LHCb dataset, 2011-2018. Oxford played a formative role in the 3-pion version of the Run 1 analysis and is now taking forward this analysis on the full dataset. The data analysis part of the studentship will focus entirely on these decays. This may require the development of an angular analysis to demonstrate maximum sensitivity of the data. Publication is anticipated in the 3rd year of the studentship. In addition to the data analysis, the studentship will be augmented by the following hardware project. The LHCC recently approved the LHCb collaboration to move towards TDRs for a second upgrade to LHCb around 2030. The purpose is to fully exploit the high-luminosity LHC for flavour physics but it comes the considerable challenge of how to correctly identify displaced vertex signatures in bunch-crossing events with high pile-up. The accepted solution is to use fast timing (around 100ps resolution) to separate vertices in both space and time. Fundamental to this is silicon detectors for the vertex detector. The next generation hybrid silicon pixel chips, Timepix4, has 200ps resolution and will be available to collaborating institutes in 2019. The student will take a leading role in the laboratory characterisation of this chip with sources. The student will then spend a extended period (12-15 months) at CERN to participate in beam tests of these chips in 2021, publishing these results in the 4th year of the studentship. Two conferences are thus envisaged, one presenting physics results, the other on the result of the test beam. No summer school beyond that provided by STFC is expected.