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dc.contributor.advisorZwicky, Roman
dc.contributor.advisorGardi, Einan
dc.contributor.authorGratrex, James
dc.date.accessioned2018-10-24T10:59:25Z
dc.date.available2018-10-24T10:59:25Z
dc.date.issued2018-11-29
dc.identifier.urihttp://hdl.handle.net/1842/33173
dc.description.abstractRecent results at the LHCb and B-factory experiments have suggested that rare processes in B →Vγ and B → V ℓ¯ℓ decays, where V is a vector meson, show some deviation from Standard Model predictions. Although these anomalies are not yet at the level to constitute a formal discovery, they are certainly suggestive of potential New Physics effects in flavour-changing neutral currents. However, explanations within the Standard Model cannot yet be ruled out. This thesis contributes to the understanding of such anomalies in two ways. Firstly, the angular distribution of the B → KJ (→ Kπ)ℓ1¯ℓ2 decay is derived, for the full dimension-six effective weak Hamiltonian, using a generalisation of the helicity formalism to effective theories mediating b → sℓ1¯ℓ2 transitions. This approach sheds light on the origin of the underlying structure, and in the process extends the general angular distribution to decays in which the two leptons in the final state, ℓ1¯ℓ2, are not necessarily identical. An additional benefit of the derivation of the angular distribution presented in this manner is that it lends itself to a moments analysis of the decay. It is shown how the angular distribution changes in the presence of new operators, predicted to be vanishingly small in the Standard Model. Such operators could be sizeable in the presence of New Physics, but using a moments analysis enables the contribution of such operators to be assessed. Secondly, an analysis is presented of the three-particle vector and axial meson distribution amplitudes. It is shown that the distribution amplitudes of both particles are, up to QCD corrections, nearly identical. These results are applied to a new calculation of the long-distance charm loop contribution to radiative B → Vγ decays, and it is shown that the approximate symmetry can be exploited to provide an improved theoretical control in the search for New Physics contributions to right-handed currents in radiative decays.en
dc.contributor.sponsorScience and Technology Facilities Council (STFC)en
dc.language.isoenen
dc.publisherThe University of Edinburghen
dc.relation.hasversionJ. Gratrex, M. Hopfer, and R. Zwicky, "Generalised helicity formalism, higher moments and the B → Kᴊᴋ(→ Kπ)¯ℓ1ℓ2 angular distributions," Phys. Rev. D93 no. 5, (2016) 054008, arXiv:1506.03970 [hep-ph].en
dc.relation.hasversionJ. Gratrex and R. Zwicky, "Parity Doubling as a Tool for Right-handed Current Searches," JHEP 08 (2018) 178, arXiv:1804.09006 [hep-ph].en
dc.relation.hasversionJ. Gratrex and R. Zwicky, "Right-handed Currents Searches and Parity Doubling," in 53rd Rencontres de Moriond on QCD and High Energy Interactions (Moriond QCD 2018) La Thuile, Italy, March 17-24. 2018. arXiv:1807.01643 [hep-ph].en
dc.subjectparticle physicsen
dc.subjectB Mesonsen
dc.subjectradiative decaysen
dc.subjectsemileptonic decaysen
dc.titleRare radiative and semileptonic B meson decaysen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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