Observation of charge–parity symmetry breaking in baryon decays
Nature Springer Nature (2025) 1-6
Authors:
R Aaij, ASW Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, AA Adefisoye, B Adeva, M Adinolfi, P Adlarson, C Agapopoulou, CA Aidala, Z Ajaltouni, S Akar, K Akiba, P Albicocco, J Albrecht, F Alessio, M Alexander, Z Aliouche, P Alvarez Cartelle, R Amalric, S Amato, JL Amey, Y Amhis, L An, L Anderlini, M Andersson, A Andreianov, P Andreola, M Andreotti, D Andreou, A Anelli, D Ao, F Archilli, M Argenton, S Arguedas Cuendis, A Artamonov, M Artuso, E Aslanides, R Ataíde Da Silva, M Atzeni, B Audurier, D Bacher, I Bachiller Perea, S Bachmann, M Bachmayer, JJ Back, P Baladron Rodriguez, V Balagura, A Balboni, W Baldini, L Balzani, H Bao, J Baptista de Souza Leite, C Barbero Pretel, M Barbetti, IR Barbosa, RJ Barlow, M Barnyakov, S Barsuk, W Barter, J Bartz, JM Basels, S Bashir, B Batsukh, PB Battista, A Bay, A Beck, M Becker, F Bedeschi, IB Bediaga, NA Behling, S Belin, K Belous, I Belov, I Belyaev, G Benane, G Bencivenni, E Ben-Haim, A Berezhnoy, R Bernet, S Bernet Andres, A Bertolin, C Betancourt, F Betti, J Bex, Ia Bezshyiko, O Bezshyyko, J Bhom, MS Bieker, NV Biesuz, P Billoir, A Biolchini, M Birch, FCR Bishop, A Bitadze, A Bizzeti, T Blake, F Blanc, JE Blank, S Blusk, V Bocharnikov, JA Boelhauve, O Boente Garcia, T Boettcher, A Bohare, A Boldyrev, CS Bolognani, R Bolzonella, RB Bonacci, N Bondar, A Bordelius, F Borgato, S Borghi, M Borsato, JT Borsuk, E Bottalico, SA Bouchiba, M Bovill, TJV Bowcock, A Boyer, C Bozzi, JD Brandenburg, A Brea Rodriguez, N Breer, J Brodzicka, A Brossa Gonzalo, J Brown, D Brundu, E Buchanan, L Buonincontri, M Burgos Marcos, AT Burke, C Burr, JS Butter, J Buytaert, W Byczynski, S Cadeddu, H Cai, A Caillet, R Calabrese, S Calderon Ramirez, L Calefice, S Cali, M Calvi, M Calvo Gomez, P Camargo Magalhaes, JI Cambon Bouzas, P Campana, DH Campora Perez, AF Campoverde Quezada, S Capelli, L Capriotti, R Caravaca-Mora, A Carbone, L Carcedo Salgado, R Cardinale, A Cardini, P Carniti, L Carus, A Casais Vidal, R Caspary, G Casse, M Cattaneo, G Cavallero, V Cavallini, S Celani, S Cesare, AJ Chadwick, I Chahrour, H Chang, M Charles, Ph Charpentier, E Chatzianagnostou, M Chefdeville, C Chen, S Chen, Z Chen, A Chernov, S Chernyshenko, X Chiotopoulos, V Chobanova, M Chrzaszcz, A Chubykin, V Chulikov, P Ciambrone, X Cid Vidal, G Ciezarek, P Cifra, PEL Clarke, M Clemencic, HV Cliff, J Closier, C Cocha Toapaxi, V Coco, J Cogan, E Cogneras, L Cojocariu, S Collaviti, P Collins, T Colombo, M Colonna, A Comerma-Montells, L Congedo, A Contu, N Cooke, C Coronel, I Corredoira, A Correia, G Corti, J Cottee Meldrum, B Couturier, DC Craik, M Cruz Torres, E Curras Rivera, R Currie, CL Da Silva, S Dadabaev, L Dai, X Dai, E Dall’Occo, J Dalseno, C D’Ambrosio, J Daniel, A Danilina, P d’Argent, G Darze, A Davidson, JE Davies, O De Aguiar Francisco, C De Angelis, F De Benedetti, J de Boer, K De Bruyn, S De Capua, M De Cian, U De Freitas Carneiro Da Graca, E De Lucia, JM De Miranda, L De Paula, M De Serio, P De Simone, F De Vellis, JA de Vries, F Debernardis, D Decamp, V Dedu, S Dekkers, L Del Buono, B Delaney, H-P Dembinski, J Deng, V Denysenko, O Deschamps, F Dettori, B Dey, P Di Nezza, I Diachkov, S Didenko, S Ding, L Dittmann, V Dobishuk, AD Docheva, C Dong, AM Donohoe, F Dordei, AC dos Reis, AD Dowling, W Duan, P Duda, MW Dudek, L Dufour, V Duk, P Durante, MM Duras, JM Durham, OD Durmus, A Dziurda, A Dzyuba, S Easo, E Eckstein, U Egede, A Egorychev, V Egorychev, S Eisenhardt, E Ejopu, L Eklund, M Elashri, J Ellbracht, S Ely, A Ene, J Eschle, S Esen, T Evans, F Fabiano, S Faghih, LN Falcao, Y Fan, B Fang, L Fantini, M Faria, K Farmer, D Fazzini, L Felkowski, M Feng, M Feo, A Fernandez Casani, M Fernandez Gomez, AD Fernez, F Ferrari, F Ferreira Rodrigues, M Ferrillo, M Ferro-Luzzi, S Filippov, RA Fini, M Fiorini, M Firlej, KL Fischer, DS Fitzgerald, C Fitzpatrick, T Fiutowski, F Fleuret, M Fontana, LF Foreman, R Forty, D Foulds-Holt, V Franco Lima, M Franco Sevilla, M Frank, E Franzoso, G Frau, C Frei, DA Friday, J Fu, Q Führing, Y Fujii, T Fulghesu, E Gabriel, G Galati, MD Galati, A Gallas Torreira, D Galli, S Gambetta, M Gandelman, P Gandini, B Ganie, H Gao, R Gao, TQ Gao, Y Gao, Y Gao, LM Garcia Martin, P Garcia Moreno, J Garca Pardiñas, P Gardner, KG Garg, L Garrido, C Gaspar, A Gavrikov, LL Gerken, E Gersabeck, M Gersabeck, T Gershon, S Ghizzo, Z Ghorbanimoghaddam, L Giambastiani, FI Giasemis, V Gibson, HK Giemza, AL Gilman, M Giovannetti, A Gioventù, L Girardey, C Giugliano, MA Giza, FC Glaser, VV Gligorov, C Göbel, L Golinka-Bezshyyko, E Golobardes, D Golubkov, A Golutvin, S Gomez Fernandez, W Gomulka, F Goncalves Abrantes, M Goncerz, G Gong, JA Gooding, IV Gorelov, C Gotti, E Govorkova, JP Grabowski, LA Granado Cardoso, E Graugés, E Graverini, L Grazette, G Graziani, AT Grecu, LM Greeven, NA Grieser, L Grillo, S Gromov, C Gu, M Guarise, L Guerry, V Guliaeva, PA Günther, A-K Guseinov, E Gushchin, Y Guz, T Gys, K Habermann, T Hadavizadeh, C Hadjivasiliou, G Haefeli, C Haen, G Hallett, MM Halvorsen, PM Hamilton, J Hammerich, Q Han, X Han, S Hansmann-Menzemer, L Hao, N Harnew, TH Harris, M Hartmann, S Hashmi, J He, F Hemmer, C Henderson, RDL Henderson, AM Hennequin, K Hennessy, L Henry, J Herd, P Herrero Gascon, J Heuel, A Hicheur, G Hijano Mendizabal, J Horswill, R Hou, Y Hou, N Howarth, J Hu, W Hu, X Hu, W Huang, W Hulsbergen, RJ Hunter, M Hushchyn, D Hutchcroft, M Idzik, D Ilin, P Ilten, A Inglessi, A Iniukhin, A Ishteev, K Ivshin, R Jacobsson, H Jage, SJ Jaimes Elles, S Jakobsen, E Jans, BK Jashal, A Jawahery, V Jevtic, E Jiang, X Jiang, Y Jiang, YJ Jiang, M John, A John Rubesh Rajan, D Johnson, CR Jones, TP Jones, S Joshi, B Jost, J Juan Castella, N Jurik, I Juszczak, D Kaminaris, S Kandybei, M Kane, Y Kang, C Kar, M Karacson, D Karpenkov, A Kauniskangas, JW Kautz, MK Kazanecki, F Keizer, M Kenzie, T Ketel, B Khanji, A Kharisova, S Kholodenko, G Khreich, T Kirn, VS Kirsebom, O Kitouni, S Klaver, N Kleijne, K Klimaszewski, MR Kmiec, S Koliiev, L Kolk, A Konoplyannikov, P Kopciewicz, P Koppenburg, A Korchin, M Korolev, I Kostiuk, O Kot, S Kotriakhova, A Kozachuk, P Kravchenko, L Kravchuk, M Kreps, P Krokovny, W Krupa, W Krzemien, O Kshyvanskyi, S Kubis, M Kucharczyk, V Kudryavtsev, E Kulikova, A Kupsc, BK Kutsenko, I Kyryllin, D Lacarrere, P Laguarta Gonzalez, A Lai, A Lampis, D Lancierini, C Landesa Gomez, JJ Lane, R Lane, G Lanfranchi, C Langenbruch, J Langer, O Lantwin, T Latham, F Lazzari, C Lazzeroni, R Le Gac, H Lee, R Lefèvre, A Leflat, S Legotin, M Lehuraux, E Lemos Cid, O Leroy, T Lesiak, ED Lesser, B Leverington, A Li, C Li, C Li, H Li, J Li, K Li, L Li, M Li, P Li, P-R Li, Q Li, S Li, T Li, T Li, Y Li, Y Li, Z Lian, X Liang, S Libralon, C Lin, T Lin, R Lindner, H Linton, V Lisovskyi, R Litvinov, D Liu, FL Liu, G Liu, K Liu, S Liu, W Liu, Y Liu, Y Liu, YL Liu, G Loachamin Ordonez, A Lobo Salvia, A Loi, T Long, JH Lopes, A Lopez Huertas, S López Soliño, Q Lu, C Lucarelli, D Lucchesi, M Lucio Martinez, V Lukashenko, Y Luo, A Lupato, E Luppi, K Lynch, X-R Lyu, G M., S Maccolini, F Machefert, F Maciuc, B Mack, I Mackay, LM Mackey, LR Madhan Mohan, MJ Madurai, A Maevskiy, D Magdalinski, D Maisuzenko, JJ Malczewski, S Malde, L Malentacca, A Malinin, T Maltsev, G Manca, G Mancinelli, C Mancuso, R Manera Escalero, FM Manganella, D Manuzzi, D Marangotto, JF Marchand, R Marchevski, U Marconi, E Mariani, S Mariani, C Marin Benito, J Marks, AM Marshall, L Martel, G Martelli, G Martellotti, L Martinazzoli, M Martinelli, D Martinez Gomez, D Martinez Santos, F Martinez Vidal, A Martorell I Granollers, A Massafferri, R Matev, A Mathad, V Matiunin, C Matteuzzi, KR Mattioli, A Mauri, E Maurice, J Mauricio, P Mayencourt, J Mazorra de Cos, M Mazurek, M McCann, TH McGrath, NT McHugh, A McNab, R McNulty, B Meadows, G Meier, D Melnychuk, FM Meng, M Merk, A Merli, L Meyer Garcia, D Miao, H Miao, M Mikhasenko, DA Milanes, A Minotti, E Minucci, T Miralles, B Mitreska, DS Mitzel, A Modak, L Moeser, RA Mohammed, RD Moise, EF Molina Cardenas, T Mombächer, M Monk, S Monteil, A Morcillo Gomez, G Morello, MJ Morello, MP Morgenthaler, J Moron, W Morren, AB Morris, AG Morris, R Mountain, H Mu, ZM Mu, E Muhammad, F Muheim, M Mulder, K Müller, F Muñoz-Rojas, R Murta, V Mytrochenko, P Naik, T Nakada, R Nandakumar, T Nanut, I Nasteva, M Needham, E Nekrasova, N Neri, S Neubert, N Neufeld, P Neustroev, J Nicolini, D Nicotra, EM Niel, N Nikitin, Q Niu, P Nogarolli, P Nogga, C Normand, J Novoa Fernandez, G Nowak, C Nunez, HN Nur, A Oblakowska-Mucha, V Obraztsov, T Oeser, S Okamura, A Okhotnikov, O Okhrimenko, R Oldeman, F Oliva, M Olocco, CJG Onderwater, RH O’Neil, D Osthues, JM Otalora Goicochea, P Owen, A Oyanguren, O Ozcelik, F Paciolla, A Padee, KO Padeken, B Pagare, T Pajero, A Palano, M Palutan, X Pan, G Panshin, L Paolucci, A Papanestis, M Pappagallo, LL Pappalardo, C Pappenheimer, C Parkes, D Parmar, B Passalacqua, G Passaleva, D Passaro, A Pastore, M Patel, J Patoc, C Patrignani, A Paul, CJ Pawley, A Pellegrino, J Peng, M Pepe Altarelli, S Perazzini, D Pereima, H Pereira Da Costa, A Pereiro Castro, P Perret, A Perrevoort, A Perro, MJ Peters, K Petridis, A Petrolini, JP Pfaller, H Pham, L Pica, M Piccini, L Piccolo, B Pietrzyk, G Pietrzyk, RN Pilato, D Pinci, F Pisani, M Pizzichemi, V Placinta, M Plo Casasus, T Poeschl, F Polci, M Poli Lener, A Poluektov, N Polukhina, I Polyakov, E Polycarpo, S Ponce, D Popov, S Poslavskii, K Prasanth, C Prouve, D Provenzano, V Pugatch, G Punzi, S Qasim, QQ Qian, W Qian, N Qin, S Qu, R Quagliani, RI Rabadan Trejo, JH Rademacker, M Rama, M Ramírez García, V Ramos De Oliveira, M Ramos Pernas, MS Rangel, F Ratnikov, G Raven, M Rebollo De Miguel, F Redi, J Reich, F Reiss, Z Ren, PK Resmi, M Ribalda Galvez, R Ribatti, GR Ricart, D Riccardi, S Ricciardi, K Richardson, M Richardson-Slipper, K Rinnert, P Robbe, G Robertson, E Rodrigues, A Rodriguez Alvarez, E Rodriguez Fernandez, JA Rodriguez Lopez, E Rodriguez Rodriguez, J Roensch, A Rogachev, A Rogovskiy, DL Rolf, P Roloff, V Romanovskiy, A Romero Vidal, G Romolini, F Ronchetti, T Rong, M Rotondo, SR Roy, MS Rudolph, M Ruiz Diaz, RA Ruiz Fernandez, J Ruiz Vidal, J Ryzka, JJ Saavedra-Arias, JJ Saborido Silva, R Sadek, N Sagidova, D Sahoo, N Sahoo, B Saitta, M Salomoni, I Sanderswood, R Santacesaria, C Santamarina Rios, M Santimaria, L Santoro, E Santovetti, A Saputi, D Saranin, A Sarnatskiy, G Sarpis, M Sarpis, C Satriano, A Satta, M Saur, D Savrina, H Sazak, F Sborzacchi, A Scarabotto, S Schael, S Scherl, M Schiller, H Schindler, M Schmelling, B Schmidt, S Schmitt, H Schmitz, O Schneider, A Schopper, N Schulte, S Schulte, MH Schune, G Schwering, B Sciascia, A Sciuccati, I Segal, S Sellam, A Semennikov, T Senger, M Senghi Soares, A Sergi, N Serra, L Sestini, A Seuthe, Y Shang, DM Shangase, M Shapkin, RS Sharma, I Shchemerov, L Shchutska, T Shears, L Shekhtman, Z Shen, S Sheng, V Shevchenko, B Shi, Q Shi, Y Shimizu, E Shmanin, R Shorkin, JD Shupperd, R Silva Coutinho, G Simi, S Simone, M Singha, N Skidmore, T Skwarnicki, MW Slater, E Smith, K Smith, M Smith, A Snoch, L Soares Lavra, MD Sokoloff, FJP Soler, A Solomin, A Solovev, I Solovyev, NS Sommerfeld, R Song, Y Song, Y Song, YS Song, FL Souza De Almeida, B Souza De Paula, E Spadaro Norella, E Spedicato, JG Speer, E Spiridenkov, P Spradlin, V Sriskaran, F Stagni, M Stahl, S Stahl, S Stanislaus, M Stefaniak, EN Stein, O Steinkamp, O Stenyakin, H Stevens, D Strekalina, Y Su, F Suljik, J Sun, L Sun, D Sundfeld, W Sutcliffe, K Swientek, F Swystun, A Szabelski, T Szumlak, Y Tan, Y Tang, MD Tat, A Terentev, F Terzuoli, F Teubert, E Thomas, DJD Thompson, H Tilquin, V Tisserand, S T’Jampens, M Tobin, L Tomassetti, G Tonani, X Tong, T Tork, D Torres Machado, L Toscano, DY Tou, C Trippl, G Tuci, N Tuning, LH Uecker, A Ukleja, DJ Unverzagt, A Upadhyay, B Urbach, A Usachov, A Ustyuzhanin, U Uwer, V Vagnoni, V Valcarce Cadenas, G Valenti, N Valls Canudas, J van Eldik, H Van Hecke, E van Herwijnen, CB Van Hulse, R Van Laak, M van Veghel, G Vasquez, R Vazquez Gomez, P Vazquez Regueiro, C Vázquez Sierra, S Vecchi, JJ Velthuis, M Veltri, A Venkateswaran, M Verdoglia, M Vesterinen, D Vico Benet, P Vidrier Villalba, M Vieites Diaz, X Vilasis-Cardona, E Vilella Figueras, A Villa, P Vincent, B Vivacqua, FC Volle, D vom Bruch, N Voropaev, K Vos, C Vrahas, J Wagner, J Walsh, EJ Walton, G Wan, A Wang, C Wang, G Wang, H Wang, J Wang, J Wang, J Wang, J Wang, M Wang, NW Wang, R Wang, X Wang, X Wang, XW Wang, Y Wang, YW Wang, Z Wang, Z Wang, Z Wang, JA Ward, M Waterlaat, NK Watson, D Websdale, Y Wei, J Wendel, BDC Westhenry, C White, M Whitehead, E Whiter, AR Wiederhold, D Wiedner, G Wilkinson, MK Wilkinson, M Williams, MJ Williams, MRJ Williams, R Williams, Z Williams, FF Wilson, M Winn, W Wislicki, M Witek, L Witola, G Wormser, SA Wotton, H Wu, J Wu, X Wu, Y Wu, Z Wu, K Wyllie, S Xian, Z Xiang, Y Xie, TX Xing, A Xu, L Xu, M Xu, Z Xu, Z Xu, Z Xu, K Yang, S Yang, X Yang, Y Yang, Z Yang, V Yeroshenko, H Yeung, H Yin, X Yin, CY Yu, J Yu, X Yuan, Y Yuan, E Zaffaroni, M Zavertyaev, M Zdybal, F Zenesini, C Zeng, M Zeng, C Zhang, D Zhang, J Zhang, L Zhang, S Zhang, S Zhang, Y Zhang, YZ Zhang, Z Zhang, Y Zhao, A Zhelezov, SZ Zheng, XZ Zheng, Y Zheng, T Zhou, X Zhou, Y Zhou, V Zhovkovska, LZ Zhu, X Zhu, X Zhu, V Zhukov, J Zhuo, Q Zou, D Zuliani, G Zunica
Abstract:
The Standard Model of particle physics—the theory of particles and interactions at the smallest scale—predicts that matter and antimatter interact differently due to violation of the combined symmetry of charge conjugation (C) and parity (P). Charge conjugation transforms particles into their antimatter particles, whereas the parity transformation inverts spatial coordinates. This prediction applies to both mesons, which consist of a quark and an antiquark, and baryons, which are composed of three quarks. However, despite having been discovered in various meson decays, CP violation has yet to be observed in baryons, the type of matter that makes up the observable Universe. Here we report a study of the decay of the beauty baryon Λ0b$${\varLambda }_{0}^{b}$$ to the pK−π+π− final state, which proceeds through b → u or b → s quark-level transitions, and its CP-conjugated process, using data collected by the Large Hadron Collider beauty experiment1 at the European Organization for Nuclear Research (CERN). The results reveal significant asymmetries between the decay rates of the Λ0b$${\varLambda }_{0}^{b}$$ baryon and its CP-conjugated antibaryon, providing, to our knowledge, the first observation of CP violation in baryon decays and demonstrating the different behaviours of baryons and antibaryons. In the Standard Model, CP violation arises from the Cabibbo–Kobayashi–Maskawa mechanism2, and new forces or particles beyond the Standard Model could provide further contributions. This discovery opens a new path in the search for physics beyond the Standard Model.