The measurement of the Unitarity Triangle, gamma, from neutral B0 mesons using the full LHCb Run I and II dataset

Lead Research Organisation: University of Oxford
Department Name: Oxford Physics


This student will focus of the LHCb group's flagship measurement of the Unitarity Triangle, gamma. For the first 18-20 months, she will develop the analysis of B0->D0K*0 in the suppressed, and gamma-sensitive, "ADS" modes of the D meson, Kpi, Kpipipi and possibly Kpipi0, all of which have been developed by previous D.Phil students in the context of similar B->D0h decays. The Kpi mode has been searched for in the LHCb Run I dataset but the other two final states have not been attempted. Good signals are expected from the combination of Run I and Run II data, easily within the timescale of this studentship. By the end of the funding period, Run II will be complete and the student will be responsible for producing the complete suite of all B0->D0K*0analyses with the full dataset, including the model-independent GGSZ analysis, originally proposed and pioneered by the Oxford group. She will also perform all the statistical inference work to conclude on a value for gamma. This is expected to be measured to within 4 deg with Run II. The novel aspect of B0 decays in the pursuit of gamma is that the two processes that interfere to allow access to the phase information are both suppressed to a similar level. This means the relative amplitude is comparatively large and the CP-violating effects (charge asymmetries) are potentially more significant. This mode does suffer from feed-down background from partially reconstructed decays of the heavier Bs meson, but through a partnership with colleagues in the Warwick group who have similar interests, we believe this background is well understood. In addition to the analysis work, the student will participate in the running of the vertex detector and/or the forward shower counters of LHCb whilst stationed at CERN. Simulation studies relating to a future LHCb upgrade are also expected from this student. Though such work will be hugely valuable to the collaboration and will help shape any future proposal to STFC for heavy-flavour physics, it will be included in the thesis only if strong thematic links are made with the core gamma analysis.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/N504233/1 01/10/2015 30/09/2021
1793195 Studentship ST/N504233/1 01/10/2016 31/03/2020 Hannah Pullen
Description LHCb collaboration 
Organisation European Organization for Nuclear Research (CERN)
Department Large Hadron Collider Beauty Experiment (LHCb)
Country Switzerland 
Sector Public 
PI Contribution I have performed two analyses of LHCb data, one of which resulted in a published paper for the collabortion.
Collaborator Contribution The data I have analysed in my research was collected by the LHCb experiment at CERN between 2011 and 2018. I was part of a physics working group at LHCb, which provided assistance with research techniques and helped me to publish an analysis.
Impact I have published a paper as a member of the LHCb collaboration.
Start Year 2016