Confirmation of an enhancement in theμ+μ−mass spectrum at 9.5 GeV

The reaction $p+\mathrm{Fe}\to {\mu }^{+}+{\mu }^{-}+$ anything has been measured at an incident momentum of 400 GeV/c. An enhancement of the order of 80 events is observed with $M_{\mu \mu }=9.5\mathrm{}$ GeV at approximately the 4-standard-deviation level.