Journal Article

Observation of the doubly-charmed-baryon decay $$ {\\Xi}_{cc}^{++}\\to {\\Xi}_c^0{\\pi}^{+}{\\pi}^{+}

Baladron Rodriguez, P., Blake, T., Battista, P. B., Akiba, K., Bediaga, I. B., Barsuk, S., Alexander, M., Andreou, D., Ajaltouni, Z., Benane, G., Aaij, R., Belov, I., Anderlini, L., Belin, S., Bachmayer, M., Balagura, V., Bieker, M. S., Barlow, R. J., Anelli, A., Becker, M., Balzani, L., Bacher, D., Bernet Andres, S., Bedeschi, F., Belous, K., Biesuz, N. V., Atzeni, M., Abellan Beteta, C., Ao, D., Amalric, R., Adeva, B., Barbosa, I. R., Bencivenni, G., Baptista de Souza Leite, J., Albicocco, P., Bhom, J., Barter, W., Blanc, F., Adefisoye, A. A., Adinolfi, M., Aslanides, E., Bao, H., Bashir, S., Abdelmotteleb, A. S. W., Andreotti, M., Betti, F., Akar, S., Barnyakov, M., Bezshyiko, Ia, Albrecht, J., Behling, N. A., Ackernley, T., Billoir, P., Bezshyyko, O., Amhis, Y., Back, J. J., Balboni, A., Barbetti, M., Belyaev, I., Baldini, W., Berezhnoy, A., Argenton, M., Ataíde Da Silva, R., Bachmann, S., Bishop, F. C. R., Audurier, B., Blank, J. E., Artuso, M., Bernet, R., An, L., Adlarson, P., Artamonov, A., Aliouche, Z., Archilli, F., Aidala, C. A., Birch, M., Batsukh, B., Beck, A., Betancourt, C., Arguedas Cuendis, S., Abudinén, F., Agapopoulou, C., Bita

2025

Overview

A search for the doubly-charmed-baryon decay $$ {\\Xi}_{cc}^{++}\\to {\\Xi}_c^0{\\pi}^{+}{\\pi}^{+} $$ Ξ cc + + → Ξ c 0 π + π + is performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 5 . 4 fb − 1 . A significant structure consistent with the $$ {\\Xi}_{cc}^{++} $$ Ξ cc + + baryon is observed in the $$ {\\Xi}_c^0{\\pi}^{+}{\\pi}^{+} $$ Ξ c 0 π + π + invariant-mass spectrum. Using the $$ {\\Xi}_{cc}^{++}\\to {\\Lambda}_c^{+}{K}^{-}{\\pi}^{+}{\\pi}^{+} $$ Ξ cc + + → Λ c + K − π + π + decay as the normalisation channel, the branching fraction ratio, $$ \\frac{\\mathcal{B}\\left({\\Xi}_{cc}^{++}\\to {\\Xi}_c^0{\\pi}^{+}{\\pi}^{+}\\right)}{\\mathcal{B}\\left({\\Xi}_{cc}^{++}\\to {\\Lambda}_c^{+}{K}^{-}{\\pi}^{+}{\\pi}^{+}\\right)} $$ B Ξ cc + + → Ξ c 0 π + π + B Ξ cc + + → Λ c + K − π + π + , is measured to be 1 . 37 ± 0 . 18 (stat) ± 0 . 09 (syst) ± 0 . 35 (ext). This measurement provides critical input for testing QCD factorisation methods in the weak decays of doubly-heavy baryons, particularly in quantifying nonperturbative effects such as final-state interactions and resonance contributions to the hadronisation process.