Measurement of $\it{\Lambda}_\it{b}^0$, $\it{\Lambda}_\it{c}^+$ and $\it{\Lambda}$ decay parameters using $\it{\Lambda}_\it{b}^0 \to \it{\Lambda}_\it{c}^+ h^-$ decays

• Main Authors: Albrecht, J, Amey, J. L, Anderlini, L, Ao, D, Da Silva, R. Ataide, Bachmann, S, Basels, J. M, Belyaev, I, Blake, T, Bolzonella, R, Bovill, M, Buonaura, A, Burr, C, Butter, J. S, Caillet, A. C, Ramirez, S. Calderon, Caravaca-Mora, R, Chahrour, I, Chobanova, V, Chulikov, V, Collins, P, Contu, A, Daniel, J, De Lucia, E, de Vries, J. A, Dembinski, H. -P, Ferrillo, M, Ferro-Luzzi, M, Fini, R. A, Forty, R, Foulds-Holt, D, Frei, C, Giugliano, C, Gligorov, V. V, Goncerz, M, Haefeli, G, Halvorsen, M. M, Hashmi, S, Mendizabal, G. Hijano, Hu, X, Hushchyn, M, Kandybei, S, Kenzie, M, Kirsebom, V. S, Kopciewicz, P, Kutsenko, B. K, Lane, J. J, Lane, R, Lehuraux, M, Li, C, Li, P. -R, Long, T, Martinez, M. Lucio, Mackay, I, Santos, D. Martinez, Matev, R, Mazurek, M, McGrath, T. H, Mitreska, B, Mu, H, Oblakowska-Mucha, A, Obraztsov, V, Okamura, S, Onderwater, C. J. G, Goicochea, J. M. Otalora, Patel, M, Peng, J, Perazzini, S, Pfaller, J. P, Pham, H, Pinci, D, Placinta, V, Casasus, M. Plo, Roloff, P, Rudolph, M. S, Saitta, B, Rios, C. Santamarina, Saputi, A, Savrina, D, Smead, L. G. Scantlebury, Schmitt, S, Sergi, A, Sestini, L, Shapkin, M, Smith, K, Solovev, A, Spiridenkov, E, Swystun, F, Teubert, F, Tomassetti, L, Tuci, G, Bruch, D. vom, Walsh, J, Wang, C, Wang, J, Watson, N. K, Wu, H, Yang, X, Yang, Y, Zaffaroni, E
• Format: Journal Article
• Language: English
• Published: 04.09.2024
• Subjects: Physics - High Energy Physics - Experiment
• DOI: 10.48550/arxiv.2409.02759

A comprehensive study of the angular distributions in the bottom-baryon decays $\it{\Lambda}^\mathrm{0}_b\to\it{\Lambda}_c^+ h^-(h=\pi, K)$, followed by $\it{\Lambda}_c^+\to\it{\Lambda} h^+$ with $\it{\Lambda}\to \it{p} \pi^-$ or $\it{\Lambda}_c^+\to\it{p}\it{K}^0_\mathrm{S}$ decays, is performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of $9~\mathrm{fb}^{-1}$ collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 $\mathrm{Te\kern -0.1em V}$. The decay parameters and the associated charge-parity ($C\!P$) asymmetries are measured, with no significant $C\!P$ violation observed. For the first time, the $\it{\Lambda}^\mathrm{0}_b \to \it{\Lambda}_c^+ h^-$ decay parameters are measured. The most precise measurements of the decay parameters $\alpha, \beta$ and $\gamma$ are obtained for $\it{\Lambda}_c^+$ decays and an independent measurement of the decay parameters for the strange-baryon $\it{\Lambda}$ decay is provided. The results deepen our understanding of weak decay dynamics in baryon decays.