Exploring charm decays with missing energy in leptoquark models

Abstract

Abstract We investigate the possibility that scalar leptoquarks generate consequential effects on the flavor-changing neutral-current decays of charmed hadrons into final states with missing energy carried away by either standard model or sterile neutrinos. We focus on scenarios involving the R 2, R ˜ 2 $$ {\tilde{R}}_2 $$ , and S ¯ 1 $$ {\overline{S}}_1 $$ leptoquarks and take into account various pertinent constraints, learning that meson-mixing ones and those inferred from collider searches can be of significance. We find in particular that the branching fractions of charmed meson decays D → , M = π, ρ, and D s → and singly charmed baryon decays Λ c + $$ {\Lambda}_c^{+} $$ → and Ξ c → are presently allowed to attain the 10 −7-10 −6 levels if induced by R 2 and that the impact of R ˜ 2 $$ {\tilde{R}}_2 $$ is comparatively much less. In contrast, the contributions of S ¯ 1 $$ {\overline{S}}_1 $$ , which couples to right-handed up-type quarks and the sterile neutrinos, could lead to branching fractions as high as order 10 −3. This suggests that these charmed hadron decays might be within reach of the BESIII and Belle II experiments or future super charm-tau factories and could serve as potentially promising probes of leptoquark interactions with sterile neutrinos.

Keywords

• Beyond Standard Model
• Heavy Quark Physics
• Effective Field Theories
• Neutrino Physics