Search for Hidden-Sector Bosons in B0→K*0μ+μ− Decays

Abstract

A search is presented for hidden-sector bosons, χ , produced in the decay B 0 → K ∗ ( 892 ) 0 χ , with K ∗ ( 892 ) 0 → K + π − and χ → μ + μ − . The search is performed using p p -collision data corresponding to 3.0 fb − 1 collected with the LHCb detector. No significant signal is observed in the accessible mass range 214 ≤ m ( χ ) ≤ 4350 MeV , and upper limits are placed on the branching fraction product B ( B 0 → K ∗ ( 892 ) 0 χ ) × B ( χ → μ + μ − ) as a function of the mass and lifetime of the χ boson. These limits are of the order of 1 0 − 9 for χ lifetimes less than 100 ps over most of the m ( χ ) range, and place the most stringent constraints to date on many theories that predict the existence of additional low-mass bosons.