An overview of the most important progresses in charm physics since the last CKM Workshop (2014) is presented. Due emphasis is given to the experimental measurements directly related to the CKM matrix.
The $bar PANDA$ experiment at FAIR (Facility for Antiproton and Ion Research) in Darmstadt (Germany) is designed for $bar p p$ annihilation studies and it will investigate fundamental questions of hadron and nuclear physics in interactions of antipro
tons with nucleons and nuclei. Gluonic excitations and the physics of hadrons with strange and charm quarks will be accessible with unprecedented accuracy, thereby allowing high precision tests of the strong interactions. In particular, the $D_{s0}^*(2317)^+$ and $D_{s1}(2460)^+$ are still of high interest 11 years after their discovery, because they can not be simply understood in term of potential models. The available statistics and resolution of the past experiments did not allow to clarify their nature. Recently LHCb at CERN has made progresses in this respect, but still not at the level of precision required in order to clarify the puzzle of the $cs$-spectrum. $bar PANDA$ will be able to achieve a factor 20 higher mass resolution than attained at the B-factories, which is expected to be decisive on these and second-order open questions. The technique to evaluate the width from the excitation function of the cross section of the $D_s$ mesons will be presented, and ongoing simulations performed with $PandaRoot$ will be shown.
We present recent results on light mesons based on Dalitz plot analyses of charm decays from Fermilab experiment E791. Scalar mesons are found to have large contributions to the decays studied, $D^+to K^-pi^+pi^+$ and $D^+, D_s^+topi^-pi^+pi^+$. From
the $Kpipi$ final state, we find good evidence for the existence of the light and broad $kappa$ meson and we measure its mass and width. We also discuss recently published results on the 3$pi$ final states, especially the measurement of the $f_0$ parameters and the evidence for the $sigma$ meson from $D^+tosigmapi^+$. These results demonstrate the importance of charm decays as a new environment for the study of light meson physics.
The Cabibbo-Kobayashi-Maskawa matrix is a key element to describe flavour dynamics in the Standard Model. With only four parameters, this matrix is able to describe a large range of phenomena in the quark sector, such as CP violation and rare decays.
It can thus be constrained by many different processes, which have to be measured experimentally with a high accuracy and computed with a good theoretical control. With the advent of the B factories and the LHCb experiment taking data, the precision has significantly improved recently. The most relevant experimental constraints and theoretical inputs are reviewed and fits to the CKM matrix are presented for the Standard Model and for some topical model-independent studies of New Physics.
An overview of the recent first observation of CP violation in the Charm sector by the LHCb collaboration. Selection of theoretical models explaining this measurement is reviewed. Finally, experimental prospects for future measurements are discussed.