Long-lived population of the metastable 2s state in muonic hydrogen

Preliminary experimental results of the search for long-lived metastable mu p(2s) are presented. The mu p(2s) are identified via muon transfer to neon in a gas mixture of hydrogen and several percent of neon at mbar pressures . An energy-dependent 1s transfer rate to neon has been observed. The time spectra can only be explained assuming a nonzero mu p(2s) population.