Banh, Huy (2026) Probing Annihilation Topologies in B+ to J/psi pi+ and B+ to J/psi K+. Master's Thesis / Essay, Physics.
|
Text
Final-version---MSc-Thesis---Huy-Banh.pdf Download (2MB) | Preview |
Abstract
Precision studies of the B-meson system provide sensitive tests of the Standard Model. In particular, a precise determination of the Bd0-Bd0bar mixing phase phi_d requires reliable control of subleading decay topologies, since their effects could otherwise be mistaken for new-physics effects. In this thesis, we extend an established global-fit strategy, implemented within GammaCombo, by including annihilation topologies in the charged control modes B+ -> J/psi pi+ and B+ -> J/psi K+ and investigate their impact on phi_d. Using only measurements of CP asymmetries, the fit becomes underconstrained once annihilation contributions are included. By additionally including the ratio of CP-averaged branching fractions together with a Gaussian constraint on the relevant hadronic amplitude ratio, the hadronic parameters can be determined uniquely. Comparing the fitted values of phi_d with and without annihilation topologies, we find that the central value shifts by only delta phi_d = 0.03 degrees. As a cross-check, we also develop a fixed-point strategy to estimate the associated systematic uncertainty, which corresponds to about 10% of the 68% experimental interval width. We therefore conclude that annihilation contributions are negligible given the current experimental precision on phi_d, even with projected end-of-HL-LHC and Belle II precision.
| Item Type: | Thesis (Master's Thesis / Essay) |
|---|---|
| Supervisor name: | Bruyn, K.A.M. de |
| Degree programme: | Physics |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 03 Jul 2026 14:30 |
| Last Modified: | 03 Jul 2026 14:30 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/37336 |
Actions (login required)
 |
View Item |