Dortmund 2021 – wissenschaftliches Programm
T 6.8: Vortrag
Montag, 15. März 2021, 17:45–18:00, Tf
Rare charm c → uνν dineutrino null test for e+ e−–machines — •Rigo Bause, Hector Gisbert, Marcel Golz, and Gudrun Hiller — TU Dortmund
Rare |Δ c|=|Δ u|=1 transitions into dineutrinos are strongly GIM-suppressed and constitute excellent null tests of the standard model. While branching ratios of c → u νν transitions are experimentally unconstrained, signals of new physics can be just around the corner.
Signatures of these modes, including D → P ν ν or D → P+ P− ν ν with P=π, K, Λc → p ν ν, contain missing energy and are well suited for experimental searches at e+ e−–facilities, such as BES III, Belle II and future e+ e−–colliders, such as the FCC-ee running at the Z.
Using current bounds on c → u ℓ+ ℓ− transitions, model-independent upper limits on branching ratios assuming lepton universality and charged lepton flavour conservation are presented (arxiv:2010.02225). An observation in excess of these upper limits implies a breakdown of the corresponding symmetry.