Search for a light dark sector particle at LHCb

A search is presented for a hidden-sector boson, $χ$, produced in the decay $B^0 \rightarrow K^* (892)^0 χ$, with $K^* (892)^0 \rightarrow K^+ π^-$ and $χ\rightarrow μ^+ μ^-$ . The search is performed using a $pp$-collision data sample collected at $\sqrt{s}=7$ and 8 TeV with the LHCb detector, corresponding to integrated luminosities of 1 and 2 fb$^{-1}$ respectively. No significant signal is observed in the mass range $214 \le m_χ\le 4350$ MeV, and upper limits are placed on the branching fraction product $\mathcal{B}(B^0 \rightarrow K^* (892)^0 χ) \times \mathcal{B}(χ\rightarrow μ^+ μ^- )$ as a function of the mass and lifetime of the $χ$ boson. These limits place the most stringent constraints to date on many theories that predict the existence of additional low-mass dark bosons.

No reviews yet.

No comments yet.