3 research outputs found
Non-leptonic B-decays in and beyond QCD Factorisation
This thesis examines the non-leptonic B-decays within QCD factorisation and
beyond, to challenge the assumptions and limitations of the method. We analyse
the treatment of the distribution amplitudes of light mesons and present a new
model described by simple physical parameters. The leading twist distribution
amplitudes of light mesons describe the leading non-perturbative hadronic
contributions to exclusive QCD reactions at large energy transfer, for instance
electromagnetic form factors. Importantly, they also enter into the two-body B
decay amplitudes described by QCD factorisation. They cannot be calculated from
first principles and are described by models based on a fixed-order conformal
expansion, which is not always sufficient in phenomenological applications. We
derive new models that are valid to all orders in the conformal expansion and
characterised by a small number of parameters related to experimental
observables.Motivated by the marginal agreement between the QCD factorisation
results with the experimental data, in particular for , we
scrutinise the incalculable non-factorisable corrections to charmless
non-leptonic decays. We use the available results on to extract
information about the size and nature of the required non-factorisable
corrections that are needed to reconcile the predictions and data. We find that
the best-fit scenarios do not give reasonable agreement to until at
least a 40% non-factorisable contribution is added. Finally we consider the
exclusive decays, where we analyse the recently updated
experimental data within QCD factorisation and present constraints on generic
supersymmetric models using the mass insertion approximation.Comment: 132 pages, PHD thesis; full text with high-resolution figures
available from http://www.ippp.dur.ac.uk/Research/Theses/talbot.ps.g
Models for Light-Cone Meson Distribution Amplitudes
Leading-twist distribution amplitudes (DAs) of light mesons like pi,rho etc.
describe the leading nonperturbative hadronic contributions to exclusive QCD
reactions at large energy transfer, for instance electromagnetic form factors.
They also enter B decay amplitudes described in QCD factorisation, in
particular nonleptonic two-body decays. Being nonperturbative quantities, DAs
cannot be calculated from first principles, but have to be described by models.
Most models for DAs rely on a fixed order conformal expansion, which is
strictly valid for large factorisation scales, but not always sufficient in
phenomenological applications. We derive models for DAs that are valid to all
orders in the conformal expansion and characterised by a small number of
parameters which are related to experimental observables.Comment: 19 pages, 10 figure
Open data from the first and second observing runs of Advanced LIGO and Advanced Virgo
Advanced LIGO and Advanced Virgo are monitoring the sky and collecting gravitational-wave strain data with sufficient sensitivity to detect signals routinely. In this paper we describe the data recorded by these instruments during their first and second observing runs. The main data products are gravitational-wave strain time series sampled at 16384 Hz. The datasets that include this strain measurement can be freely accessed through the Gravitational Wave Open Science Center at http://gw-openscience.org, together with data-quality information essential for the analysis of LIGO and Virgo data, documentation, tutorials, and supporting software