Pentaquarks with Charm at H1

A narrow resonance in D*^-p and D^*+ bar p invariant mass combinations is observed in inelastic electron-proton collisions at centre-of-mass energies of 300 GeV and 320 GeV at the HERA collider. The resonance has a mass of 3099 ± 3 (stat.) ± 5 (syst.) MeV and a measured Gaussian width of 12 ± 3 (stat.) MeV, compatible with the experimental resolution. The resonance is interpreted as an anti-charmed baryon with the minimal constituent quark composition of uuddbar c , together with its charge conjugate state.