Search for a long-lived spin-0 mediator in b RIGHTWARDS ARROW s transitions at the Belle II experiment
2023
Abstract
Additional spin-0 particles appear in many extensions of the standard model. We search for long-lived spin-0 particles S in B-meson decays mediated by a b -> s quark transition in e+e- collisions at the ϒ(4S) resonance at the Belle II experiment.
Based on a sample corresponding to an integrated luminosity of 189 fb-1, we observe no evidence for signal. We set model-independent upper limits on the product of branching fractions B(B0 -> K*(892)0(-> K+ pi-)S) x B(S -> x+x-) and B(B+ -> K+S) x B(S -> x+x-), where x+x- indicates e+e-; mu+mu-; pi+ pi-, or K+K-, as functions of S mass and lifetime at the level of 10-7.