Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2020-2021)

The discovery of Higgs boson by LHC in 2012 was an important step in validating the Standard Model (SM). However, there are already tensions between certain data and theoretical calculations based on SM. To make definite conclusions from these tensions, we need to improve the accuracy of both the measurement data and theoretical calculations. With the increase in luminosity and energy LHCb Run II (2015-19) expects to, at least, quadruple its effective statistics with the data collected until 2019 and hence half the uncertainties on the current measurements. In addition, SuperKEKB, which is an upgrade project of KEKB (1998-2010) at KEK (Japan) is designed to increase the instantaneous luminosity by about a factor of 40. Along with the BELLE II detector, this next-generation B-factory will complement the exploration of New Physics beyond the Standard Model currently being carried out at the energy frontier by LHC. The physics run of SuperKEKB will start in 2017. The numerous decay channels of the B mesons (quark-antiquark bound state containing a b-quark) to light mesons (quark-antiquark bound state with no b-quark) offer the opportunity to make precision tests of the Standard Model and perhaps more interestingly, to look for signals of physics beyond the SM. Exclusive B decays to light mesons are appealing since they are relatively easy to access experimentally, especially in an environment like the LHC. On the other hand, the theory of such decays is challenging due to the strong interactions effects. The theory of strong interactions, which is called quantum chromodynamics (QCD), becomes complicated when dealing with bound-state quantities. The computation of these quantities is challenging and model-dependent. Therefore, it is very important to make SM predictions using alternative viable approaches to nonperturbative QCD.
In this research, we focus on increasing the reliability of our theoretical predictions for the exclusive B decays on both the perturbative and non-perturbative sides. First, we use an alternative and complimentary method to model QCD bound state effects. This method is known as light-front holography (LFH) and can be used to compute the non-perturbative inputs in theoretical calculations. Second, we are apply the so-called Principle of Maximum Conformality (PMC) to reduce the scale dependence of our theoretical predictions.
We also plan to investigate the underlying connection between LFH and chiral perturbation theory which is another successful model for describing nonperturbative QCD. One should be able to deduce this connection by matching their predictions for the same physical quantity at a common kinematical range where both models are expected to be valid.