Karlsruhe 2024 – scientific programme

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T: Fachverband Teilchenphysik

T 125: Flavour physics 6

T 125.5: Talk

Friday, March 8, 2024, 10:00–10:15, Geb. 30.41: HS 4

Revisiting D→π ℓ⁺ ℓ⁻ in the Standard Model using LCSR — •Anshika Bansal, Alexander Khodjamirian, and Thomas Mannel — Theoretical Particle Physics, Center for Particle Physics Siegen, University of Siegen

Recently, LHCb has significantly updated the upper bound on the flavour changing neutral current (FCNC) semi-leptonic charm decay (D⁺→π⁺µ⁺µ⁻). With these updates, it is important to re-analyse the theoretical predictions for this mode as, unlike for the down quark sector, the FCNC for the up-sector are very challenging due to strong GIM suppression of short distance contributions. This leads the branching fraction to be dominated by the long distance effects. In this talk, I will discuss D → π ℓ⁺ ℓ⁻ decays in the U-spin symmetry limit. I will further discuss the use of the method of Light Cone Sum Rules to compute these long distance contributions and the associated challenges. Lastly, I will provide some estimates for the branching ratio.

Keywords: Rare charm decays; Light Cone Sum Rules; Long distance effects