Dark photon and dark Z mediated B meson decays
Alakabha Datta, A. Hammad, Danny Marfatia, Lopamudra Mukherjee, Ahmed Rashed
Abstract
A bstract We study flavor changing neutral current decays of B and K mesons in the dark U(1) D model, with the dark photon/dark Z mass between 10 MeV and 2 GeV. Although the model provides an improved fit (compared to the standard model) to the differential decay distributions of B → K (∗) ℓ + ℓ − , with ℓ = μ , e , and B s → ϕμ + μ − , the allowed parameter space is ruled out by measurements of atomic parity violation, K + → μ + + invisible decay, and $$ {B}_s-{\overline{B}}_s $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mi>s</mml:mi> </mml:msub> <mml:mo>−</mml:mo> <mml:msub> <mml:mover> <mml:mi>B</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>s</mml:mi> </mml:msub> </mml:math> mixing, among others. To evade constraints from low energy data, we extend the model to allow for (1) additional invisible Z D decay, (2) a direct vector coupling of Z D to muons, and (3) a direct coupling of Z D to both muons and electrons, with the electron coupling fine-tuned to cancel the Z D coupling to electrons via mixing. We find that only the latter case survives all constraints.