School of Physics Experimental Particle Physics


Our researchers and some the projects they are working on with the Belle collaboration


Professor Geoff Taylor

Associate Professor Martin Sevior

Associate Professor Elisabetta Barberio

Current Student Research

Measurement of the Branching Fraction of B -> pi0 pi0


The aim of my project is to improve the measurement of B -> pi0 pi0 using data gathered by the Belle experiment at KEK. Measuring the fraction of times a B meson decays in to a pair of neutral pions in comparison to the times an anti-B meson undergoes the same decay will allow us to calculate how often CP violation happens within the B meson system. This is just one of the measurements being made at Belle, as it is important to calculate CP violation using a variety of possible B decays to compare and confirm different the results with each other.

About two in every million B mesons will decay in this way. To put this in perspective, there are about 771 million pairs of B mesons available for analysis, so it is very important to accurately differentiate between the signal events, or events we want, and the background events, or events that are from other things happening within the detector. To do this I write reconstruction code to find the events I want, and then test it efficiency on simulated data. When my code is optimised in the simulation I run it over the real Belle data and make a measurement. This was last done at the Belle collaboration in 2004. Since then we have gained 4 times the data, as well as made advancements in analysis techniques, making it possible to greatly improve the accuracy of these results. This will lead to an improved measurement of this mode and, by extension, CP violation.

T'Mir Danger Julius

Ph.D. Student

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