Experimental studies on charm hadrons with the Beijing Spectrometer Ⅲ

Charm hadrons are particles composed of a charm quark paired with a light quark (u, d, s) to form charm mesons, or with a pair of light quarks to form charm baryons. In the ground state of the strong interaction they are referred to as ground-state charm mesons (D⁰, D⁺, D_s⁺) and ground-state charm baryons (Λ_c⁺). The decays of ground-state charm hadrons are dominated by weak interactions involving quark flavor transitions. This leads to a rich variety of decay patterns, making them an excellent testing ground for comprehensive studies of weak interaction theory from multiple perspectives. On the other hand, during the weak decay process, ground-state charm mesons emit a W gauge boson and transform into light quarks, which then undergo strong interactions, recombining to form final-state hadrons. The decays of ground-state charm hadrons are thus also used to probe the mechanisms of strong interactions. Experiments at the Beijing Spectrometer Ⅲ facility have collected a large amount of data at center-of-mass energies of 3.773, 4.128—4.226, and 4.6—4.95 GeV. This article briefly recounts a series of results obtained using these data to study the decays of ground-state charm hadrons.