Application of light-cone sum rules (LCSRs) to D(s)->Pl+l- decays

by Dr Anshika Bansal (Universität Siegen)

Thursday 10 Jul 2025, 16:00 → 17:00 Europe/Berlin

CP-03-123 (TU Dortmund)

$D^+\to \pi^+\ell^+\ell^-$ decays are of much interest from the point of view of GIM cancellation and potential new sources of the FCNC $c\to u$ transitions. The hadronic amplitude of this decay is dominated by the combination of weak annihilation with the emission of a virtual photon which are purely long-distance effects.

In this talk, I will discuss a new method to analyse these decays, combining QCD light-cone sum rules (LCSRs) with hadronic dispersion relations. This method allows us to determine relative strong phases of the ρ-,ω- and ϕ-meson resonances and to estimate of the contributions of heavier hadronic states. The final results for $D^+\to \pi^+\ell^+\ell^-$ width are obtained to be not much smaller than the current upper bound measured by LHCb collaboration. In the later part of my talk, I will discuss the relations of these decays to other Cabibbo favoured and Cabbbo suppressed modes using U-spin symmetry. Finally, I present results for Cabibbo-favoured modes, $D_s^+\to \pi^+\ell^+\ell^-$ and $D^0\to \bar{K}^0\ell^+\ell^-$, which proceed via the same weak annihilation mechanism as a byproduct of our analysis.

Zoom link

announcement.pdf