The angular analysis of the B0 to K*0μ+μ- decay at LHCb
Author(s)
Parkinson, Christopher
Type
Thesis
Abstract
The Standard Model (SM) of particle physics is an incomplete description of the fundamental
particles and their interactions. In extensions of the SM, new physics particles are
expected to appear at the ~ TeV mass scale. The discovery of such new physics particles
could help to answer some of the greatest questions in physics: what constitutes `dark'
matter; why is there more matter than antimatter; are there more than four dimensions?
Particles at the ~ TeV scale are expected to contribute virtually to interactions between
SM particles at ~ GeV energy scales. In interactions that are mediated by loop
processes, such as the flavour-changing neutral current decay B0 to K*0μ+μ-, the contribution
from new physics particles can be as large as that of SM particles. Certain
experimentally accessible observables of the B0 to K*0μ+μ- decay are precisely predicted
in the SM and in new physics models. Any deviation in the measured value of the observables
from the SM prediction would indicate a contribution from new physics particles.
This thesis reports the analysis of the world's largest sample of B0 to K*0μ+μ- decays.
The decays are isolated in data collected at the LHCb experiment in the √s = 7TeV pp
collisions at the Large Hadron Collider, corresponding to 1 fb-1 of integrated luminosity.
An angular analysis of the decays is performed to extract various observables. There
is no significant deviation from the SM prediction in any of the measurements. The lack
of new physics contributions to the B0 to K*0μ+μ- decay indicates either that the new
physics mass scale is significantly higher than ~1TeV, or that the flavour couplings of
the new physics particles are highly suppressed. These results impose stringent, model-independent constraints on new physics particles at the ~TeV mass scale.
particles and their interactions. In extensions of the SM, new physics particles are
expected to appear at the ~ TeV mass scale. The discovery of such new physics particles
could help to answer some of the greatest questions in physics: what constitutes `dark'
matter; why is there more matter than antimatter; are there more than four dimensions?
Particles at the ~ TeV scale are expected to contribute virtually to interactions between
SM particles at ~ GeV energy scales. In interactions that are mediated by loop
processes, such as the flavour-changing neutral current decay B0 to K*0μ+μ-, the contribution
from new physics particles can be as large as that of SM particles. Certain
experimentally accessible observables of the B0 to K*0μ+μ- decay are precisely predicted
in the SM and in new physics models. Any deviation in the measured value of the observables
from the SM prediction would indicate a contribution from new physics particles.
This thesis reports the analysis of the world's largest sample of B0 to K*0μ+μ- decays.
The decays are isolated in data collected at the LHCb experiment in the √s = 7TeV pp
collisions at the Large Hadron Collider, corresponding to 1 fb-1 of integrated luminosity.
An angular analysis of the decays is performed to extract various observables. There
is no significant deviation from the SM prediction in any of the measurements. The lack
of new physics contributions to the B0 to K*0μ+μ- decay indicates either that the new
physics mass scale is significantly higher than ~1TeV, or that the flavour couplings of
the new physics particles are highly suppressed. These results impose stringent, model-independent constraints on new physics particles at the ~TeV mass scale.
Version
Open Access
Date Issued
2013-06
Date Awarded
2013-10
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Egede, Ulrik
Patel, Mitesh
Publisher Department
Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)