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v3.3.2-pre
For detailed information on the 10th International Workshop on the CKM Unitarity Triangle see
https://ckm2018.physi.uni-heidelberg.de
Abstract: I will discuss how one can estimate the (dominant) resonant contributions to these family of rare decays and how this compares with the first experimental results recently published by LHCb and BaBar. I will also briefly comment on the potential for new physics searches in these decay modes.
The study of mesons and baryons which contain at least one charm quark is referred to as open charm physics. It offers the possibility to study up-type quark transitions. Since the q ̧uark can not be treated in any mass limit, theoretical predictions are difficult and experimental input is crucial. BESIII collected large data samples of e+e− collisions at several charm thresholds. The at-threshold decay topology offers special opportunities to study open charm decays.
We present a selection of recent BESIII results: The measurement of the branching fraction D+s → pn, the observation of the decay D->a0(980)0 e+ nu_e, the search for the semi-leptonic decay D+->D0 e+ nu_e and the search for rare decays D → h(h′)e+e−.
The study of mesons and baryons which contain at least one charm quark is referred to as open charm physics. It offers the possibility to study up-type quark transitions. Since the q ̧uark can not be treated in any mass limit, theoretical predictions are difficult and experimental input is crucial. BESIII collected large data samples of e+e− collisions at several charm thresholds. The at-threshold decay topology offers special opportunities to study open charm decays.
In particlular, the model independent measurement of the strong phase between D0 and D0bar is unique to this production process. Furthermore, a search for direct CPV and the measurement of y_CP is presented.
We examine simplified models for explaining RK(*) and related measurements. At tree-level, one has the option of leptoquarks or Z's with flavour dependent couplings. One can search for either at hadron colliders, and, focussing on the Z' explanation, we show that the prospects for future searches are good, especially if the energy of the collisions is increased. We give a simple example (The Third Family Hypercharge Model) that predicts a Z' with the right couplings to explain RK(*). The model explains the hierarchical heaviness of the third family and the smallness of CKM mixing. Such models raise the exciting prospect of a direct experimental probe of physics pertinent to the fermion masses and mixings problem.
Leptoquarks occur in many new physics scenarios and could be the next big discovery at the LHC. I will discuss a model-independent search strategy covering all possible leptoquarks is possible and has not yet been fully exploited. To be systematic we organize the possible leptoquark final states according to a leptoquark matrix with entries corresponding to nine experimentally distinguishable leptoquark decays: any of {light-jet, b-jet, top} with any of {neutrino, e/μ, τ}. The 9 possibilities can be explored in a largely model-independent fashion with pair-production of leptoquarks at the LHC. I will review the status of experimental searches for the 9 components of the leptoquark matrix. Based on current limits, I will derive bounds on a complete set of Minimal Leptoquark models which span all possible flavor and gauge representations for scalar and vector leptoquarks.
I will introduce a toolbox for precision collider studies of the leptoquark production mechanisms in the proton-proton collisions. The study I plan to present was prompted by the need for an up-to-date Monte Carlo event generator output that could be used for the current and future experimental searches and search recasts. I will, accordingly, report the NLO QCD inclusive cross sections in proton-proton collisions at various center-of-mass energies for all on-shell leptoquark production processes and, in view of these results, discuss the leptoquark search strategy.
An experimental overview of direct searches for leptoquarks at the LHC is presented. Results are shown for single and pair-production, including the first search to include generation mixing between the lepton and quark, and a synthesis of all current LHC searches is made. Results are put into the context of the b-flavor anomalies seen at LHCb, Belle, and Babar, stressing the possibilities for future searches which shed the assumptions of previous searches.
Coherent new physics picture of B-anomalies (both) in charged and neutral current transitions, is a rather challenging task. I will review two directions which recently triggered some activity in the literature and are centered around (i) the Pati-Salam vector leptoquark, and (ii) the light sterile neutrino.