Experimental overview on the charmed baryon decays

Abstract

The charmed baryon was first observed experimentally in 1975, one year after the charm quark's confirmation via the discovery of the $J/ψ$ particle. Studying charmed baryon decays provides a pathway to investigate both strong and weak interactions, leveraging the weak decays of the embedded charm quark. However, for approximately three decades following its discovery, experimental knowledge of charmed baryons remained significantly limited compared to those of the hidden-charm $ψ$ mesons and open-charm $D_{(s)}$ mesons. This situation changed markedly starting in 2014, when dedicated data collection for charmed baryons commenced at BESIII. In this article, we review the experimental progress achieved since 2014 in understanding the weak decays of the charmed baryons.

Figures (7)

• Figure 1: Family of antitriplet and sextet ground-state charmed baryons.
• Figure 2: Plot (a): Distribution of the cross sections of the production $e^+e^-\to\Lambda_{c}^{+}\overline{\Lambda}{}_{c}^{-}$ measured by BESIII BESIII:2023rwvBESIII:2017kqg and Belle Belle:2008xmh. Plot (b): Distributions of the extracted effective form factors measured by BESIII BESIII:2023rwvBESIII:2017kqg
• Figure 3: (left) The missing mass distribution for the neutrino signals in $\Lambda_{c}^{+}\to \Lambda e^+ \nu_e$. (right) Comparisons of the determined form factors in $\Lambda_{c}^{+}\to \Lambda \ell^+ \nu_\ell$ with LQCD calculation.
• Figure 4: Comparison of (a) $\mathcal{B}(\Lambda_{c}^{+}\to n\pi^+)$ v.s. $\mathcal{B}(\Lambda_{c}^{+}\to p\pi^0)$ and (b) the ratio $\mathcal{B}(\Lambda_{c}^{+}\to p\pi^0)/\mathcal{B}(\Lambda_{c}^{+}\to p\eta )$ with Belle result Belle:2021mvw and previous theoretical calculations piror to the BESIII result of $\mathcal{B}(\Lambda_{c}^{+}\to p\pi^0)$BESIII:2024mgg. The theoretical calculations contain constituent quark model (CQM) Uppal:1994pt with two predictions (A) and (B), heavey quark effective theory (HQET) Chen:2002jr, dynamical calculation based on the pole model and current algebra (PMCA) Cheng:2018hwl, topological-diagram approach (TDA) with the results of TDA I Zhao:2018mov and TDA II Hsiao:2021nsc with solutions S1 and S2, and a few SU(3) flavor symmetry approaches, including SU(3) I Sharma:1996sc, SU(3) II Lu:2016ogy, SU(3) III Geng:2018plk, SU(3) IV O($\overline{15})$Geng:2018rse, SU(3) V Geng:2019xbo, SU(3) VI Xing:2023dni and SU(3) VII Zhong:2022exp under SU(3) broken and symmetric approaches.
• Figure 5: (left) Definitions of the helicity frames and related angles for $e^{+}e^{-}\to\Lambda_{c}^{+}\bar{\Lambda}_c^{-}, \Lambda_{c}^{+}\to\Xi^{0}K^{+}, \Xi^{0}\to\Lambda\pi^0$, and $\Lambda\to p\pi^{-}$. (right) Projections of the best fit onto different angular distributions. Black points with error bars are data, red solid lines represent the fitting results.