RESUMEN
Weak radiative hyperon decays, important to test the strong interaction and relevant in searches for beyond the standard model physics, have remained puzzling both experimentally and theoretically for a long time. The recently updated branching fraction and first measurement of the asymmetry parameter of Λânγ by the BESIII Collaboration further exacerbate the issue, as none of the existing predictions can describe the data. We show in this work that the covariant baryon chiral perturbation theory, with constraints from the latest measurements of hyperon non-leptonic decays, can well describe the BESIII data. The predicted branching fraction and asymmetry parameter for Ξ-âΣ-γ are also in agreement with the experimental data. We note that a more precise measurement of the asymmetry parameter, which is strongly constrained by chiral symmetry and related with that of Σ+âpγ, is crucial to test Hara's theorem. We further predict the branching fraction and asymmetry parameter of Σ0ânγ, whose future measurement can serve as a highly nontrivial check on our understanding of weak radiative hyperon decays and on the covariant baryon chiral perturbation theory.
Asunto(s)
Neoplasias Colorrectales , Obstrucción Intestinal , Stents Metálicos Autoexpandibles , Humanos , Obstrucción Intestinal/etiología , Obstrucción Intestinal/cirugía , Obstrucción Intestinal/terapia , Neoplasias Colorrectales/complicaciones , Neoplasias Colorrectales/cirugía , Masculino , Resultado del Tratamiento , Anciano , Femenino , Persona de Mediana Edad , Anciano de 80 o más Años , StentsRESUMEN
In this paper, black soil samples were separated into four sizes ( > 2,000, 2,000-250, 250-53, and <53 microm) of aggregates by wet sieving, and their free light fraction (free LF) and intra-aggregate particulate organic matter (iPOM) were isolated by density fractionation, aimed to evaluate the effects of manure application on the organic carbon in different sizes of aggregates in black soil. The results showed that compared with the control, applying manure improved soil aggregation significantly, and compensated the disturbance of tillage and slowed down the turnover of aggregates to some degree. After applying manure, the content of fine iPOM-C was significantly higher than that of coarse iPOM-C, suggesting that manure application was beneficial to the accumulation of fine iPOM-C, which is the main form of carbon sequestration in the aggregates of black soil.