Neutral Hadrons Disappearing into the Darkness

Understand

We study the invisible decay of neutral hadrons in a representative model of the dark sector.

• The mesons $K_L$ and $B^0$ decay into the dark sector with branching rates that can be at the current experimental limits.
• The neutron decays with a rate that could either explain the neutron lifetime puzzle (although only for an extreme choice of the parameters and a fine tuned value of the masses) or be just above the current limit of its invisible decay ($\tau_N^{\rm inv} \ge 10^{29}$ years) if kinematically allowed.
• These invisible decays of ordinary matter provide a novel and promising window into new physics that should be vigorously pursued.