Confirmation of the doubly charmed baryon [formula omitted](3520) via its decay to [formula omitted

A Ocherashvili,U Akgun,Mao Chensheng,M Procario,M Kaya,P Mathew,L Emediato,V Steiner,L Stutte,T Lungov,V.S Verebryusov,U Dersch,I Konorov,P Schiavon,Mao Zhenlin,I Eschrich,G.B Dzyubenko,E Ramberg,N.P Kuropatkin,M Iori,M Svoiski,M Luksys,E Mccliment,A Morelos,J Lach,M.Y Balatz,E Gülmez,A Penzo,G.V Davidenko,J Engelfried,V.T Kim,E.M Leikin,A Lamberto,Y Onel,S Kwan,J Russ,K Vorwalter,E Ozel,A Kushnirenko,J Simon,Zhao Wenheng,I Larin,L.G Landsberg,G Alkhazov,V.A Victorov,P Pogodin,J Kilmer,H Krüger,A.S Ayan,V.E Vishnyakov,P Gouffon,V Matveev,I Torres,A.V Nemitkin,I Giller,D Skow,M Gaspero,J Amaro-Reyes,Sining Zheng ,L Uvarov ,A P Nilov ,V A Prutskoi ,V J Smith ,E Vázquez‐Jáuregui ,A G Atamantchouk ,K D Nelson ,A N Vasiliev ,A Dolgolenko ,P S Cooper ,Dan Mao ,C Escobar ,А И Ситников ,G F Rappazzo ,S V Petrenko ,N Bondar ,R M Edelstein ,S B Nurushev ,V P Maleev ,A A Vorobyov ,N Terentyev ,V V Stepanov ,S Özkorucuklu ,V I Ruď ,A Evdokimov ,B V Razmyslovich ,А П Кожевников ,A M F Endler ,S Y Jun ,M K Srivastava ,J M You ,A Krivshich ,M Kubantsev ,L Kochenda ,M A Moinester ,C R Newsom ,F García ,D V Vavilov ,V V Molchanov ,V Golovtsov ,G Thomas ,И С Филимонов ,Kai He ,L J Dauwe ,V Kubarovsky ,V F Kurshetsov ,A I Kulyavtsev ,P V Neoustroev ,M E Mattson ,Yun-Shan Li ,R Zukanovich Funchal

doi:10.1016/j.physletb.2005.09.043

Abstract

We observe a signal for the doubly charmed baryon Ξcc+ in the decay mode Ξcc+→pD+K− to complement the previous reported decay Ξcc+→Λc+K−π+ in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38±0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8σ. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4×10−4. The observed mass of this state is 3518±3 MeV/c2, consistent with the published result. Averaging the two results gives a mass of 3518.7±1.7 MeV/c2. The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36±0.21.

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