Discovering True Muonium At LHCb

Xabier Cid Vidal, Philip Ilten, Jonathan Plews, Brian Shuve, and Yotam Soreq

Physical Review D 100 (2019) 53003


We study the potential of the LHCb experiment to discover, for the first time, the true muonium bound state. We propose a search for the vector state, which kinetically mixes with the photon and dominantly decays to electron-positron pairs. We demonstrate that a search for true muonium produced in eta meson decays and decaying at a displaced vertex can exceed a significance of 5 standard deviations assuming statistical uncertainties. We present two possible searches: an inclusive search for the electron-positron vertex, and an exclusive search which requires an additional photon and a reconstruction of the eta mass.