Exploring b to s electroweak penguin decays at LHCb
Author(s)
Shires, Alexander
Type
Thesis
Abstract
The angular distribution of B0 [to] K*0μ+μ− was studied using 1.0 fb−1 of pp collisions
recorded at the LHCb detector at the LHC. Angular observables are measured in five
independent bins of the di-muon invariant mass squared, q2, and the theoretically interesting
region from 1 < q2 < 6GeV2/c4. The results are in good agreement with Standard
Model predictions.
The contribution from a K S-wave is included in the angular distribution of B0 to K+π −ℓ+ℓ−. The K S-wave is shown to have an overall dilution effect on measurements
of the B0 [to] K+π −ℓ+ℓ− angular observables. For an S-wave contribution of 7% between
a Kπ invariant mass squared of 0.64 < p2 < 1.0GeV2/c4, there is a significant bias on
the angular observables for dataset of over 500 events. It is possible to remove this bias
by incorporating the S-wave into the angular distribution and by fitting the Kπ mass
spectrum.
The fraction of the S-wave in B0 [to] K*0μ+μ−, FS, was analysed in seven bins of q2
using 1.0 fb−1 of data from LHCb. The value of FS in the region from 1 < q2 < 6GeV2/c4
and from 0.64 < p2 < 1.0GeV2/c4 was found to be
[Equation appears here. To view, please open pdf attachment].
In the regions where no S-wave is found, 95% confidence limits are given. These measurements
show that the Kπ S-wave will be a vital consideration for future measurements of
B0 [to] K 0ℓ+ℓ−.
recorded at the LHCb detector at the LHC. Angular observables are measured in five
independent bins of the di-muon invariant mass squared, q2, and the theoretically interesting
region from 1 < q2 < 6GeV2/c4. The results are in good agreement with Standard
Model predictions.
The contribution from a K S-wave is included in the angular distribution of B0 to K+π −ℓ+ℓ−. The K S-wave is shown to have an overall dilution effect on measurements
of the B0 [to] K+π −ℓ+ℓ− angular observables. For an S-wave contribution of 7% between
a Kπ invariant mass squared of 0.64 < p2 < 1.0GeV2/c4, there is a significant bias on
the angular observables for dataset of over 500 events. It is possible to remove this bias
by incorporating the S-wave into the angular distribution and by fitting the Kπ mass
spectrum.
The fraction of the S-wave in B0 [to] K*0μ+μ−, FS, was analysed in seven bins of q2
using 1.0 fb−1 of data from LHCb. The value of FS in the region from 1 < q2 < 6GeV2/c4
and from 0.64 < p2 < 1.0GeV2/c4 was found to be
[Equation appears here. To view, please open pdf attachment].
In the regions where no S-wave is found, 95% confidence limits are given. These measurements
show that the Kπ S-wave will be a vital consideration for future measurements of
B0 [to] K 0ℓ+ℓ−.
Version
Open Access
Date Issued
2013-04
Date Awarded
2013-10
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Egede, Ulrik
Publisher Department
Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)