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Observation of the Doubly Charmed Baryon $Ξ_{c c}^{+}$ with the LHCb Run 3 Detector

R. Aaij ³⁸, M. Abdelfatah⁶⁹, A. S. W. Abdelmotteleb ⁵⁷, C. Abellan Beteta ⁵¹, F. Abudinén ⁵⁹, T. Ackernley ⁶¹, A. A. Adefisoye ⁶⁹, B. Adeva ⁴⁷, M. Adinolfi ⁵⁵ et al. (LHCb Collaboration)

M. Adinolfi ⁵⁵, P. Adlarson ^87,42, C. Agapopoulou ¹⁴, C. A. Aidala ⁸⁹, S. Akar ¹¹, K. Akiba ³⁸, P. Albicocco ²⁸, J. Albrecht ^19,b, R. Aleksiejunas ⁸¹, F. Alessio ⁴⁹, P. Alvarez Cartelle ⁴⁷, S. Amato ³, J. L. Amey ⁵⁵, Y. Amhis ¹⁴, L. An ⁶, L. Anderlini ²⁷, M. Andersson ⁵¹, P. Andreola ⁵¹, M. Andreotti ²⁶, S. Andres Estrada ⁴⁴, A. Anelli ^31,c, D. Ao ⁷, C. Arata ¹², F. Archilli ³⁷, Z. Areg ⁶⁹, M. Argenton ²⁶, S. Arguedas Cuendis ^9,49, L. Arnone ^31,c, M. Artuso ⁶⁹, E. Aslanides ¹³, R. Ataíde Da Silva⁵⁰, M. Atzeni ⁶⁵, B. Audurier ¹², J. A. Authier ¹⁵, D. Bacher ⁶⁴, I. Bachiller Perea ⁵⁰, S. Bachmann ²², M. Bachmayer ⁵⁰, J. J. Back ⁵⁷, Z. B. Bai ⁸, V. Balagura ¹⁵, A. Balboni ²⁶, W. Baldini ²⁶, Z. Baldwin ⁷⁹, L. Balzani ¹⁹, H. Bao ⁷, J. Baptista de Souza Leite ², C. Barbero Pretel ^47,12, M. Barbetti ²⁷, I. R. Barbosa ⁷⁰, R. J. Barlow ^63,a, M. Barnyakov ²⁵, S. Baron⁴⁹, S. Barsuk ¹⁴, W. Barter ⁵⁹, J. Bartz ⁶⁹, S. Bashir ⁴⁰, B. Batsukh ⁸², P. B. Battista ¹⁴, A. Bavarchee ⁸⁰, A. Bay ⁵⁰, A. Beck ⁶⁵, M. Becker ¹⁹, F. Bedeschi ³⁵, I. B. Bediaga ², N. A. Behling ¹⁹, S. Belin ⁴⁷, A. Bellavista ²⁵, I. Belov ²⁹, I. Belyaev ³⁶, G. Bencivenni ²⁸, E. Ben-Haim ¹⁶, J. L. M. Berkey ⁶⁸, R. Bernet ⁵¹, A. Bertolin ³³, F. Betti ⁵⁹, J. Bex ⁵⁶, O. Bezshyyko ⁸⁸, S. Bhattacharya ⁸⁰, M. S. Bieker ¹⁸, N. V. Biesuz ²⁶, A. Biolchini ³⁸, M. Birch ⁶², F. C. R. Bishop ¹⁰, A. Bitadze ⁶³, A. Bizzeti ^27,d, T. Blake ^57,e, F. Blanc ⁵⁰, J. E. Blank ¹⁹, S. Blusk ⁶⁹, J. A. Boelhauve ¹⁹, O. Boente Garcia ⁴⁹, T. Boettcher ⁹⁰, A. Bohare ⁵⁹, C. Bolognani ¹⁹, R. Bolzonella ^26,f, R. B. Bonacci ¹, A. Bordelius ⁴⁹, F. Borgato ^33,49, S. Borghi ⁶³, M. Borsato ^31,c, J. T. Borsuk ⁸⁶, E. Bottalico ⁶¹, S. A. Bouchiba ⁵⁰, M. Bovill ⁶⁴, T. J. V. Bowcock ⁶¹, A. Boyer ⁴⁹, C. Bozzi ²⁶, J. D. Brandenburg ⁹¹, A. Brea Rodriguez ⁵⁰, N. Breer ¹⁹, C. Breitfeld ¹⁹, J. Brodzicka ⁴¹, J. Brown ⁶¹, D. Brundu ³², E. Buchanan ⁵⁹, M. Burgos Marcos ⁸⁴, C. Burr ⁴⁹, C. Buti ²⁷, J. S. Butter ⁵⁶, J. Buytaert ⁴⁹, W. Byczynski ⁴⁹, S. Cadeddu ³², H. Cai ⁷⁵, Y. Cai ⁵, A. Caillet ¹⁶, R. Calabrese ^26,f, L. Calefice ⁴⁵, M. Calvi ^31,c, M. Calvo Gomez ⁴⁶, P. Camargo Magalhaes ^2,g, J. I. Cambon Bouzas ⁴⁷, P. Campana ²⁸, A. C. Campos ³, A. F. Campoverde Quezada ⁷, Y. Cao⁶, S. Capelli ^31,c, M. Caporale ²⁵, L. Capriotti ³³, R. Caravaca-Mora ⁹, A. Carbone ^25,h, L. Carcedo Salgado ⁴⁷, R. Cardinale ^29,i, A. Cardini ³², P. Carniti ³¹, L. Carus ²², A. Casais Vidal ⁶⁵, R. Caspary ²², G. Casse ⁶¹, M. Cattaneo ⁴⁹, G. Cavallero ²⁶, V. Cavallini ^26,f, S. Celani ⁴⁹, I. Celestino ^35,j, S. Cesare ^49,k, A. J. Chadwick ⁶¹, I. Chahrour ⁸⁹, M. Charles ¹⁶, Ph. Charpentier ⁴⁹, E. Chatzianagnostou ³⁸, R. Cheaib ⁸⁰, M. Chefdeville ¹⁰, C. Chen ⁵⁷, J. Chen ⁵⁰, S. Chen ⁵, Z. Chen ⁷, A. Chen Hu ⁶², M. Cherif ¹², S. Chernyshenko ⁵³, X. Chiotopoulos ⁸⁴, G. Chizhik ¹, V. Chobanova ⁴⁴, M. Chrzaszcz ⁴¹, V. Chulikov ^28,36,49, P. Ciambrone ²⁸, X. Cid Vidal ⁴⁷, P. Cifra ⁴⁹, P. E. L. Clarke ⁵⁹, M. Clemencic ⁴⁹, H. V. Cliff ⁵⁶, J. Closier ⁴⁹, C. Cocha Toapaxi ²², V. Coco ⁴⁹, J. Cogan ¹³, E. Cogneras ¹¹, L. Cojocariu ⁴³, S. Collaviti ⁵⁰, P. Collins ⁴⁹, T. Colombo ⁴⁹, M. Colonna ¹⁹, A. Comerma-Montells ⁴⁵, L. Congedo ²⁴, J. Connaughton ⁵⁷, A. Contu ³², N. Cooke ⁶⁰, G. Cordova ^35,j, C. Coronel ⁶⁶, I. Corredoira ¹², A. Correia ¹⁶, G. Corti ⁴⁹, G. C. Costantino ⁶¹, J. Cottee Meldrum ⁵⁵, B. Couturier ⁴⁹, D. C. Craik ⁵¹, N. Crepet ¹⁴, M. Cruz Torres ^2,l, M. Cubero Campos ⁹, E. Curras Rivera ⁵⁰, R. Currie ⁵⁹, C. L. Da Silva ⁶⁸, X. Dai ⁴, J. Dalseno ⁴⁴, C. D’Ambrosio ⁶², G. Darze ³, A. Davidson ⁵⁷, J. E. Davies ⁶³, O. De Aguiar Francisco ⁶³, C. De Angelis ^32,m, F. De Benedetti ⁴⁹, J. de Boer ³⁸, K. De Bruyn ⁸³, S. De Capua ⁶³, M. De Cian ⁶³, U. De Freitas Carneiro Da Graca ², E. De Lucia ²⁸, J. M. De Miranda ², L. De Paula ³, M. De Serio ^24,n, P. De Simone ²⁸, F. De Vellis ¹⁹, J. A. de Vries ⁸⁴, F. Debernardis ²⁴, D. Decamp ¹⁰, S. Dekkers ¹, L. Del Buono ¹⁶, B. Delaney ⁶⁵, J. Deng ⁸, V. Denysenko ⁵¹, O. Deschamps ¹¹, F. Dettori ^32,m, B. Dey ⁸⁰, P. Di Nezza ²⁸, S. Ding ⁶⁹, Y. Ding ⁵⁰, L. Dittmann ²², A. D. Docheva ⁶⁰, A. Doheny ⁵⁷, C. Dong ⁴, F. Dordei ³², A. C. dos Reis ², A. D. Dowling ⁶⁹, L. Dreyfus ¹³, W. Duan ⁷³, P. Duda ⁸⁶, L. Dufour ⁵⁰, V. Duk ³⁴, P. Durante ⁴⁹, M. M. Duras ⁸⁶, J. M. Durham ⁶⁸, O. D. Durmus ⁸⁰, K. Duwe ⁴⁹, A. Dziurda ⁴¹, S. Easo ⁵⁸, E. Eckstein ¹⁸, U. Egede ¹, S. Eisenhardt ⁵⁹, E. Ejopu ⁶¹, L. Eklund ⁸⁷, M. Elashri ⁶⁶, D. Elizondo Blanco ⁹, J. Ellbracht ¹⁹, S. Ely ⁶², A. Ene ⁴³, J. Eschle ⁶⁹, T. Evans ³⁸, F. Fabiano ¹⁴, S. Faghih ⁶⁶, L. N. Falcao ^31,c, B. Fang ⁷, R. Fantechi ³⁵, L. Fantini ^34,o, M. Faria ⁵⁰, K. Farmer ⁵⁹, F. Fassin ^83,38, D. Fazzini ^31,c, L. Felkowski ⁸⁶, C. Feng⁶, M. Feng ^5,7, A. Fernandez Casani ⁴⁸, M. Fernandez Gomez ⁴⁷, A. D. Fernez ⁶⁷, F. Ferrari ^25,h, F. Ferreira Rodrigues ³, M. Ferrillo ⁵¹, M. Ferro-Luzzi ⁴⁹, R. A. Fini ²⁴, M. Fiorini ^26,f, M. Firlej ⁴⁰, K. L. Fischer ⁶⁴, D. S. Fitzgerald ⁸⁹, C. Fitzpatrick ⁶³, T. Fiutowski ⁴⁰, F. Fleuret ¹⁵, A. Fomin ⁵², M. Fontana ^25,49, L. A. Foreman ⁶³, R. Forty ⁴⁹, D. Foulds-Holt ⁵⁹, V. Franco Lima ³, M. Franco Sevilla ⁶⁷, M. Frank ⁴⁹, E. Franzoso ^26,f, G. Frau ⁶³, C. Frei ⁴⁹, D. A. Friday ^63,49, J. Fu ⁷, Q. Führing ^19,56,b, T. Fulghesu ¹³, G. Galati ^24,n, M. D. Galati ³⁸, A. Gallas Torreira ⁴⁷, D. Galli ^25,h, S. Gambetta ⁵⁹, M. Gandelman ³, P. Gandini ³⁰, B. Ganie ⁶³, H. Gao ⁷, R. Gao ⁶⁴, T. Q. Gao ⁵⁶, Y. Gao ⁸, Y. Gao ⁶, Y. Gao ⁸, L. M. Garcia Martin ⁵⁰, P. Garcia Moreno ⁴⁵, J. García Pardiñas⁶⁵, P. Gardner ⁶⁷, L. Garrido ⁴⁵, C. Gaspar ⁴⁹, A. Gavrikov ³³, E. Gersabeck ²⁰, M. Gersabeck ²⁰, T. Gershon ⁵⁷, S. Ghizzo ^29,i, Z. Ghorbanimoghaddam ⁵⁵, F. I. Giasemis ^16,p, V. Gibson ⁵⁶, H. K. Giemza ⁴², A. L. Gilman ⁶⁶, M. Giovannetti ²⁸, A. Gioventù ⁴⁷, L. Girardey ^63,58, M. A. Giza ⁴¹, F. C. Glaser ²², V. V. Gligorov ¹⁶, C. Göbel ⁷⁰, L. Golinka-Bezshyyko ⁸⁸, E. Golobardes ⁴⁶, A. Golutvin ^62,49, S. Gomez Fernandez ⁴⁵, W. Gomulka ⁴⁰, F. Goncalves Abrantes ⁶⁴, I. Gonçales Vaz ⁴⁹, M. Goncerz ⁴¹, G. Gong ^4,q, J. A. Gooding ¹⁹, C. Gotti ³¹, E. Govorkova ⁶⁵, J. P. Grabowski ³⁰, L. A. Granado Cardoso ⁴⁹, E. Graugés ⁴⁵, E. Graverini ^35,50, L. Grazette ⁵⁷, G. Graziani ²⁷, A. T. Grecu ⁴³, N. A. Grieser ⁶⁶, L. Grillo ⁶⁰, C. Gu ¹⁵, M. Guarise ²⁶, L. Guerry ¹¹, A.-K. Guseinov ⁵⁰, Y. Guz ⁶, T. Gys ⁴⁹, K. Habermann ¹⁸, T. Hadavizadeh ¹, C. Hadjivasiliou ⁶⁷, G. Haefeli ⁵⁰, C. Haen ⁴⁹, S. Haken ⁵⁶, G. Hallett ⁵⁷, P. M. Hamilton ⁶⁷, Q. Han ³³, S. Han ⁷, X. Han ^22,49, S. Hansmann-Menzemer ²², N. Harnew ⁶⁴, T. J. Harris ¹, M. Hartmann ¹⁴, S. Hashmi ⁴⁰, J. He ^7,r, N. Heatley ¹⁴, A. Hedes ⁶³, F. Hemmer ⁴⁹, C. Henderson ⁶⁶, R. Henderson ¹⁴, R. D. L. Henderson ¹, A. M. Hennequin ⁴⁹, K. Hennessy ⁶¹, J. Herd ⁶², P. Herrero Gascon ²², J. Heuel ¹⁷, A. Heyn ¹³, A. Hicheur ³, G. Hijano Mendizabal ⁵¹, J. Horswill ⁶³, R. Hou ⁸, Y. Hou ¹¹, D. C. Houston ⁶⁰, N. Howarth ⁶¹, W. Hu ^7,r, X. Hu ⁴, W. Hulsbergen ³⁸, R. J. Hunter ⁵⁷, D. Hutchcroft ⁶¹, M. Idzik ⁴⁰, P. Ilten ⁶⁶, A. Iohner ¹⁰, H. Jage ¹⁷, S. J. Jaimes Elles ^77,48,49, S. Jakobsen ⁴⁹, T. Jakoubek ⁷⁸, E. Jans ³⁸, A. Jawahery ⁶⁷, C. Jayaweera ⁵⁴, A. Jelavic ¹, V. Jevtic ¹⁹, Z. Jia ¹⁶, E. Jiang ⁶⁷, X. Jiang ^5,7, Y. Jiang ⁷, Y. J. Jiang ⁶, E. Jimenez Moya ⁹, N. Jindal ⁹¹, M. John ⁶⁴, A. John Rubesh Rajan ²³, D. Johnson ⁵⁴, C. R. Jones ⁵⁶, S. Joshi ⁴², B. Jost ⁴⁹, J. Juan Castella ⁵⁶, N. Jurik ⁴⁹, I. Juszczak ⁴¹, K. Kalecinska⁴⁰, D. Kaminaris ⁵⁰, S. Kandybei ⁵², M. Kane ⁵⁹, Y. Kang ^4,q, C. Kar ¹¹, M. Karacson ⁴⁹, A. Kauniskangas ⁵⁰, J. W. Kautz ⁶⁶, M. K. Kazanecki ⁴¹, F. Keizer ⁴⁹, M. Kenzie ⁵⁶, T. Ketel ³⁸, B. Khanji ⁶⁹, S. Kholodenko ^62,49, G. Khreich ¹⁴, F. Kiraz¹⁴, T. Kirn ¹⁷, V. S. Kirsebom ^31,c, N. Kleijne ^35,j, A. Kleimenova ⁵⁰, D. K. Klekots ⁸⁸, K. Klimaszewski ⁴², M. R. Kmiec ⁴², T. Knospe ¹⁹, R. Kolb ²², S. Koliiev ⁵³, L. Kolk ¹⁹, A. Konoplyannikov ⁶, P. Kopciewicz ⁴⁹, P. Koppenburg ³⁸, A. Korchin ⁵², I. Kostiuk ³⁸, O. Kot ⁵³, S. Kotriakhova ³², E. Kowalczyk ⁶⁷, O. Kravcov ⁸¹, M. Kreps ⁵⁷, W. Krupa ⁴⁹, W. Krzemien ⁴², O. Kshyvanskyi ⁵³, S. Kubis ⁸⁶, M. Kucharczyk ⁴¹, A. Kupsc ^87,42, V. Kushnir ⁵², B. Kutsenko ¹³, J. Kvapil ⁶⁸, I. Kyryllin ⁵², D. Lacarrere ⁴⁹, P. Laguarta Gonzalez ⁴⁵, A. Lai ³², A. Lampis ³², D. Lancierini ⁶², C. Landesa Gomez ⁴⁷, J. J. Lane ¹, G. Lanfranchi ²⁸, C. Langenbruch ²², T. Latham ⁵⁷, F. Lazzari ^35,s, C. Lazzeroni ⁵⁴, R. Le Gac ¹³, H. Lee ⁶¹, R. Lefèvre ¹¹, M. Lehuraux ⁵⁷, E. Lemos Cid ⁴⁹, O. Leroy ¹³, T. Lesiak ⁴¹, E. D. Lesser ⁶⁸, B. Leverington ²², A. Li ^4,q, C. Li ⁴, C. Li ¹³, H. Li ⁷³, J. Li ⁸, K. Li ⁷⁶, L. Li ⁶³, P. Li ⁷, P.-R. Li ⁷⁴, Q. Li ^5,7, T. Li ⁷², T. Li ⁷³, Y. Li ⁸, Y. Li ⁵, Y. Li ⁴, Z. Lian ^4,q, Q. Liang⁸, X. Liang ⁶⁹, Z. Liang ³², S. Libralon ⁴⁸, A. Lightbody ¹², T. Lin ⁵⁸, R. Lindner ⁴⁹, H. Linton ⁶², R. Litvinov ⁶⁶, D. Liu ⁸, F. L. Liu ¹, G. Liu ⁷³, K. Liu ⁷⁴, S. Liu ⁵, W. Liu ⁸, Y. Liu ⁵⁹, Y. Liu ⁷⁴, Y. L. Liu ⁶², G. Loachamin Ordonez ⁷⁰, I. Lobo ¹, A. Lobo Salvia ¹⁰, A. Loi ³², T. Long ⁵⁶, F. C. L. Lopes ^2,g, J. H. Lopes ³, A. Lopez Huertas ⁴⁵, C. Lopez Iribarnegaray ⁴⁷, Q. Lu ¹⁵, C. Lucarelli ⁴⁹, D. Lucchesi ^33,t, M. Lucio Martinez ⁴⁸, Y. Luo ⁶, A. Lupato ^33,u, M. Lupberger ²⁰, E. Luppi ^26,f, K. Lynch ²³, S. Lyu⁶, X.-R. Lyu ⁷, H. Ma ⁷², S. Maccolini ⁴⁹, F. Machefert ¹⁴, F. Maciuc ⁴³, B. Mack ⁶⁹, I. Mackay ⁶⁴, L. M. Mackey ⁶⁹, L. R. Madhan Mohan ⁵⁶, M. J. Madurai ⁵⁴, D. Magdalinski ³⁸, J. J. Malczewski ⁴¹, S. Malde ⁶⁴, L. Malentacca ⁴⁹, G. Manca ^32,m, G. Mancinelli ¹³, C. Mancuso ¹⁴, R. Manera Escalero ⁴⁵, A. Mangalasseri ⁸⁰, F. M. Manganella ³⁷, D. Manuzzi ²⁵, S. Mao ⁷, D. Marangotto ^30,k, J. F. Marchand ¹⁰, R. Marchevski ⁵⁰, U. Marconi ²⁵, E. Mariani ¹⁶, S. Mariani ⁴⁹, C. Marin Benito ⁴⁵, J. Marks ²², A. M. Marshall ⁵⁵, L. Martel ⁶⁴, G. Martelli ¹⁹, G. Martellotti ³⁶, L. Martinazzoli ⁴⁹, M. Martinelli ^31,c, C. Martinez ³, D. Martinez Gomez ⁸³, D. Martinez Santos ⁴⁴, F. Martinez Vidal ⁴⁸, A. Martorell i Granollers ⁴⁶, A. Massafferri ², R. Matev ⁴⁹, A. Mathad ⁴⁹, C. Matteuzzi ⁶⁹, K. R. Mattioli ¹⁵, A. Mauri ⁶², E. Maurice ¹⁵, J. Mauricio ⁴⁵, P. Mayencourt ⁵⁰, J. Mazorra de Cos ⁴⁸, M. Mazurek ⁴², D. Mazzanti Tarancon ⁴⁵, M. McCann ⁶², N. T. McHugh ⁶⁰, A. McNab ⁶³, R. McNulty ²³, B. Meadows ⁶⁶, D. Melnychuk ⁴², D. Mendoza Granada ¹⁶, P. Menendez Valdes Perez ⁴⁷, F. M. Meng ^4,q, M. Merk ^38,84, A. Merli ^50,30, L. Meyer Garcia ⁶⁷, D. Miao ^5,7, H. Miao ³⁰, M. Mikhasenko ⁷⁹, D. A. Milanes ⁸⁵, A. Minotti ^31,c, E. Minucci ²⁸, B. Mitreska ⁶³, D. S. Mitzel ¹⁹, R. Mocanu ⁴³, A. Modak ⁵⁸, L. Moeser ¹⁹, R. D. Moise ¹⁷, E. F. Molina Cardenas ⁸⁹, T. Mombächer ⁴⁷, M. Monk ⁵⁶, T. Monnard ⁵⁰, S. Monteil ¹¹, A. Morcillo Gomez ⁴⁷, G. Morello ²⁸, M. J. Morello ^35,j, M. P. Morgenthaler ²², A. Moro ^31,c, J. Moron ⁴⁰, W. Morren ³⁸, A. B. Morris ^81,49, A. G. Morris ¹³, R. Mountain ⁶⁹, Z. Mu ⁶, N. Muangkod ⁶⁵, E. Muhammad ⁵⁷, F. Muheim ⁵⁹, M. Mulder ¹⁹, K. Müller ⁵¹, F. Muñoz-Rojas ⁹, V. Mytrochenko ⁵², P. Naik ⁶¹, T. 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G. Speer ¹⁹, P. Spradlin ⁶⁰, F. Stagni ⁴⁹, M. Stahl ⁷⁹, S. Stahl ⁴⁹, S. Stanislaus ⁶⁴, M. Stefaniak ⁹¹, O. Steinkamp ⁵¹, F. Suljik ⁶⁴, J. Sun ⁶³, L. Sun ⁷⁵, M. Sun⁶, D. Sundfeld ², W. Sutcliffe ⁵¹, P. Svihra ⁷⁸, V. Svintozelskyi ⁴⁸, K. Swientek ⁴⁰, F. Swystun ⁵⁶, A. Szabelski ⁴², T. Szumlak ⁴⁰, Y. Tan ⁷, Y. Tang ⁷⁵, Y. T. Tang ⁷, M. D. Tat ²², J. A. Teijeiro Jimenez ⁴⁷, F. Terzuoli ^35,v, F. Teubert ⁴⁹, E. Thomas ⁴⁹, D. J. D. Thompson ⁵⁴, A. R. Thomson-Strong ⁵⁹, H. Tilquin ⁶², V. Tisserand ¹¹, S. T’Jampens ¹⁰, M. Tobin ^5,49, T. T. Todorov ²⁰, L. Tomassetti ^26,f, G. Tonani ³⁰, X. Tong ⁶, T. Tork ³⁰, L. Toscano ¹⁹, D. Y. Tou ^4,q, C. Trippl ⁴⁶, G. Tuci ²², N. Tuning ³⁸, L. H. Uecker ²², A. Ukleja ⁴⁰, A. Upadhyay ⁴⁹, B. Urbach ⁵⁹, A. Usachov ³⁸, U. Uwer ²², V. Vagnoni ^25,49, A. Vaitkevicius ⁸¹, V. Valcarce Cadenas ⁴⁷, G. Valenti ²⁵, N. Valls Canudas ⁴⁹, J. van Eldik ⁴⁹, H. Van Hecke ⁶⁸, E. van Herwijnen ⁶², C. B. Van Hulse ^47,w, R. Van Laak ⁵⁰, M. van Veghel ⁸⁴, G. Vasquez ⁵¹, R. 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Zhu ⁵⁹, X. Zhu ^4,q, X. Zhu ⁸, Y. Zhu ¹⁷, V. Zhukov ¹⁷, J. Zhuo ⁴⁸, D. Zuliani ^33,t, and G. Zunica ²⁸ (LHCb Collaboration)

¹School of Physics and Astronomy, Monash University, Melbourne, Australia
²Centro Brasileiro de Pesquisas Físicas (CBPF), Rio de Janeiro, Brazil
³Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
⁴Department of Engineering Physics, Tsinghua University, Beijing, China
⁵Institute of High Energy Physics (IHEP), Beijing, China
⁶School of Physics State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing, China
⁷University of Chinese Academy of Sciences, Beijing, China
⁸Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China
⁹Consejo Nacional de Rectores (CONARE), San Jose, Costa Rica
¹⁰Université Savoie Mont Blanc, CNRS, IN2P3-LAPP, Annecy, France
¹¹Université Clermont Auvergne, CNRS/IN2P3, LPC, Clermont-Ferrand, France
¹²Université Paris-Saclay, Centre d’Etudes de Saclay (CEA), IRFU, Gif-Sur-Yvette, France
¹³Aix Marseille University, CNRS/IN2P3, CPPM, Marseille, France
¹⁴Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
¹⁵Laboratoire Leprince-Ringuet, CNRS/IN2P3, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France
¹⁶Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Sorbonne Université, CNRS/IN2P3, Paris, France
¹⁷I. Physikalisches Institut, RWTH Aachen University, Aachen, Germany
¹⁸Universität Bonn—Helmholtz-Institut für Strahlen und Kernphysik, Bonn, Germany
¹⁹Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany
²⁰Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
²¹Max-Planck-Institut für Kernphysik (MPIK), Heidelberg, Germany
²²Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
²³School of Physics, University College Dublin, Dublin, Ireland
²⁴INFN Sezione di Bari, Bari, Italy
²⁵INFN Sezione di Bologna, Bologna, Italy
²⁶INFN Sezione di Ferrara, Ferrara, Italy
²⁷INFN Sezione di Firenze, Firenze, Italy
²⁸INFN Laboratori Nazionali di Frascati, Frascati, Italy
²⁹INFN Sezione di Genova, Genova, Italy
³⁰INFN Sezione di Milano, Milano, Italy
³¹INFN Sezione di Milano-Bicocca, Milano, Italy
³²INFN Sezione di Cagliari, Monserrato, Italy
³³INFN Sezione di Padova, Padova, Italy
³⁴INFN Sezione di Perugia, Perugia, Italy
³⁵INFN Sezione di Pisa, Pisa, Italy
³⁶INFN Sezione di Roma La Sapienza, Roma, Italy
³⁷INFN Sezione di Roma Tor Vergata, Roma, Italy
³⁸Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands
³⁹Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam, Netherlands
⁴⁰AGH - University of Krakow, Faculty of Physics and Applied Computer Science, Kraków, Poland
⁴¹Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland
⁴²National Center for Nuclear Research (NCBJ), Warsaw, Poland
⁴³Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele, Romania
⁴⁴Universidade da Coruña, A Coruña, Spain
⁴⁵ICCUB, Universitat de Barcelona, Barcelona, Spain
⁴⁶La Salle, Universitat Ramon Llull, Barcelona, Spain
⁴⁷Instituto Galego de Física de Altas Enerxías (IGFAE), Universidade de Santiago de Compostela, Santiago de Compostela, Spain
⁴⁸Instituto de Fisica Corpuscular, Centro Mixto Universidad de Valencia—CSIC, Valencia, Spain
⁴⁹European Organization for Nuclear Research (CERN), Geneva, Switzerland
⁵⁰Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
⁵¹Physik-Institut, Universität Zürich, Zürich, Switzerland
⁵²NSC Kharkiv Institute of Physics and Technology (NSC KIPT), Kharkiv, Ukraine
⁵³Institute for Nuclear Research of the National Academy of Sciences (KINR), Kyiv, Ukraine
⁵⁴School of Physics and Astronomy, University of Birmingham, Birmingham, United Kingdom
⁵⁵H.H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom
⁵⁶Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
⁵⁷Department of Physics, University of Warwick, Coventry, United Kingdom
⁵⁸STFC Rutherford Appleton Laboratory, Didcot, United Kingdom
⁵⁹School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
⁶⁰School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom
⁶¹Oliver Lodge Laboratory, University of Liverpool, Liverpool, United Kingdom
⁶²Imperial College London, London, United Kingdom
⁶³Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
⁶⁴Department of Physics, University of Oxford, Oxford, United Kingdom
⁶⁵Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
⁶⁶University of Cincinnati, Cincinnati, Ohio, USA
⁶⁷University of Maryland, College Park, Maryland, USA
⁶⁸Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, USA
⁶⁹Syracuse University, Syracuse, New York, USA
⁷⁰Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, Brazil (associated with Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil)
⁷¹Universidad Andres Bello, Santiago, Chile (associated with Physik-Institut, Universität Zürich, Zürich, Switzerland)
⁷²School of Physics and Electronics, Hunan University, Changsha City, China (associated with Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China)
⁷³State Key Laboratory of Nuclear Physics and Technology, South China Normal University, Guangzhou, China (associated with Department of Engineering Physics, Tsinghua University, Beijing, China)
⁷⁴Lanzhou University, Lanzhou, China (associated with Institute of High Energy Physics (IHEP), Beijing, China)
⁷⁵School of Physics and Technology, Wuhan University, Wuhan, China (associated with Department of Engineering Physics, Tsinghua University, Beijing, China)
⁷⁶Henan Normal University, Xinxiang, China (associated with Institute of Particle Physics, Central China Normal University, Wuhan, Hubei, China)
⁷⁷Departamento de Fisica, Universidad Nacional de Colombia, Bogota, Colombia (associated with Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Sorbonne Université, CNRS/IN2P3, Paris, France)
⁷⁸Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic (associated with Department of Physics and Astronomy, University of Manchester, Manchester, United Kingdom)
⁷⁹Ruhr Universitaet Bochum, Fakultaet für Physik und Astronomie, Bochum, Germany (associated with Fakultät Physik, Technische Universität Dortmund, Dortmund, Germany)
⁸⁰Eotvos Lorand University, Budapest, Hungary (associated with European Organization for Nuclear Research (CERN), Geneva, Switzerland)
⁸¹Faculty of Physics, Vilnius University, Vilnius, Lithuania (associated with Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany)
⁸²Institute of Physics and Technology, Ulan Bator, Mongolia (associated with Institute of High Energy Physics (IHEP), Beijing, China)
⁸³Van Swinderen Institute, University of Groningen, Groningen, Netherlands (associated with Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands)
⁸⁴Universiteit Maastricht, Maastricht, Netherlands (associated with Nikhef National Institute for Subatomic Physics, Amsterdam, Netherlands)
⁸⁵Universidad de Ingeniería y Tecnología (UTEC), Lima, Peru (associated with Massachusetts Institute of Technology, Cambridge, Massachusetts, USA)
⁸⁶Tadeusz Kosciuszko Cracow University of Technology, Cracow, Poland (associated with Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Kraków, Poland)
⁸⁷Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden (associated with School of Physics and Astronomy, University of Glasgow, Glasgow, United Kingdom)
⁸⁸Taras Schevchenko University of Kyiv, Faculty of Physics, Kyiv, Ukraine (associated with Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France)
⁸⁹University of Michigan, Ann Arbor, Michigan, USA (associated with Syracuse University, Syracuse, New York, USA)
⁹⁰Indiana University, Bloomington, Indiana, USA (associated with Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, USA)
⁹¹Ohio State University, Columbus, Ohio, USA (associated with Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, USA)
⁹²Kent State University, Physics Department, Kent, Ohio, USA (associated with Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, USA)

^*Full author list given at the end of the Letter.
^aDeceased.
^bAlso at Lamarr Institute for Machine Learning and Artificial Intelligence, Dortmund, Germany.
^cAlso at Università degli Studi di Milano-Bicocca, Milano, Italy.
^dAlso at Università di Modena e Reggio Emilia, Modena, Italy.
^eAlso at Department of Physics and Astronomy, University of Victoria, Victoria, Canada.
^fAlso at Università di Ferrara, Ferrara, Italy.
^gAlso at Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil.
^hAlso at Università di Bologna, Bologna, Italy.
ⁱAlso at Università di Genova, Genova, Italy.
^jAlso at Scuola Normale Superiore, Pisa, Italy.
^kAlso at Università degli Studi di Milano, Milano, Italy.
^lAlso at Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras.
^mAlso at Università di Cagliari, Cagliari, Italy.
ⁿAlso at Università di Bari, Bari, Italy.
^oAlso at Università di Perugia, Perugia, Italy.
^pAlso at LIP6, Sorbonne Université, Paris, France.
^qAlso at Center for High Energy Physics, Tsinghua University, Beijing, China.
^rAlso at Hangzhou Institute for Advanced Study, UCAS, Hangzhou, China.
^sAlso at Università di Pisa, Pisa, Italy.
^tAlso at Università di Padova, Padova, Italy.
^uAlso at Università di Bergamo, Bergamo, Italy.
^vAlso at Università di Siena, Siena, Italy.
^wAlso at Universidad de Alcalá, Alcalá de Henares, Spain.
^xAlso at Università di Urbino, Urbino, Italy.

PDF

Phys. Rev. Lett. 137, 021902 – Published 8 July, 2026

DOI: https://doi.org/10.1103/dmv6-7gdv

Abstract

The first observation of the doubly charmed baryon $Ξ_{c c}^{+}$ is reported through its decay to the $Λ_{c}^{+} K^{-} π^{+}$ final state, with a statistical significance exceeding seven standard deviations. The observation is made using proton-proton collision data collected in 2024 with the LHCb Run 3 detector at a center-of-mass energy of 13.6 TeV, corresponding to a total integrated luminosity of $6.9 {fb}^{- 1}$ . The $Ξ_{c c}^{+}$ mass is measured to be $3619.97 \pm 0.83 \pm {0.26}_{- 1.30}^{+ 1.90} MeV / c^{2}$ , where the first uncertainty is statistical, the second is systematic, and the third is due to the unknown $Ξ_{c c}^{+}$ lifetime, which is assumed to lie in the range 15–160 fs with a baseline value of 45 fs. The difference between the masses of the $Ξ_{c c}^{+}$ and $Ξ_{c c}^{+ +}$ baryons is determined to be $- 1.77 \pm 0.84 \pm {0.15}_{- 1.30}^{+ 1.90} MeV / c^{2}$ . This is the first observation of a new particle made with the LHCb Run 3 detector.

Physics Subject Headings (PhySH)

Article Text

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https://cds.cern.ch/record/2959557.

Phys. Rev. Lett. 137, 021902– Published 8 July, 2026

Vol. 137, Iss. 2 — 10 July 2026

Received 31 March 2026
Revised 7 May 2026
Accepted 9 June 2026

DOI: https://doi.org/10.1103/dmv6-7gdv

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Observation of the Doubly Charmed Baryon $Ξ_{c c}^{+}$ with the LHCb Run 3 Detector

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Observation of the Doubly Charmed Baryon Ξcc+ with the LHCb Run 3 Detector

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Observation of the Doubly Charmed Baryon $Ξ_{c c}^{+}$ with the LHCb Run 3 Detector