Invariant-mass spectroscopy has been performed to search for possible resonance states in the loosely bound neutron-rich15C nucleus.By detecting alpha and11Be in coincidence,we reconstruct the excitation energy spectr...Invariant-mass spectroscopy has been performed to search for possible resonance states in the loosely bound neutron-rich15C nucleus.By detecting alpha and11Be in coincidence,we reconstruct the excitation energy spectrum for15C.To estimate the physical background from non-resonant prompt alpha particles,we employ a recently proposed weighted event-mixing method with phenomenological reduced weighting at around the alpha-decay threshold to account for the depletion in the prompt alpha's contribution owing likely to the Coulomb final-state interactions.A new weighted mixed-event method that focuses on a robust treatment of the Coulomb effect is also proposed.Through fitting the spectrum using the background estimated with these two methods,up to two resonance state candidates are proposed.Further experiments with improved statistics and theoretical calculations are called for to confirm the se resonance states.展开更多
基金Supported partially by the National Natural Science Foundation of China (12175009, 12175280, 12250610193, 11605253, 12275007)National Key Research and Development Program of China (2023YFA1606702)+3 种基金the International Partnership Program of the Chinese Academy of Sciences (016GJHZ2023063GC)Major Science and Technology Projects in Gansu Province (24GD13GA005)the support of the CAS “Light of West China” Programthe support of the Natural Science Foundation of Gansu (23JRRA676)。
文摘Invariant-mass spectroscopy has been performed to search for possible resonance states in the loosely bound neutron-rich15C nucleus.By detecting alpha and11Be in coincidence,we reconstruct the excitation energy spectrum for15C.To estimate the physical background from non-resonant prompt alpha particles,we employ a recently proposed weighted event-mixing method with phenomenological reduced weighting at around the alpha-decay threshold to account for the depletion in the prompt alpha's contribution owing likely to the Coulomb final-state interactions.A new weighted mixed-event method that focuses on a robust treatment of the Coulomb effect is also proposed.Through fitting the spectrum using the background estimated with these two methods,up to two resonance state candidates are proposed.Further experiments with improved statistics and theoretical calculations are called for to confirm the se resonance states.
