摘要
In this study,we investigate the two step sequential one pion production mechanism,that is,np(I=0)→π^(-)pp followed by the fusion reaction pp→π^(+)d,to describe the np→π^(+)π^(-)d reaction withπ^(+)π^(-)in state I=0.In this reaction,a narrow peak identified with a"d(2380)"dibaryon has been previously observed.We discover that the second reaction step pp→π^(+)d is driven by a triangle singularity that determines the position of the peak of the reaction and the high strength of the cross section.The combined cross section of these two mechanisms produces a narrow peak with a position,width,and strength,that are compatible with experimental observations within the applied approximations made.This novel interpretation of the peak accomplished without invoking a dibaryon explains why this peak has remained undetected in other reactions.
基金
support from the CIDEGENT program with Ref.CIDEGENT/2019/015
from the spanish national grant PID2019-106080GB-C21
partly supported by JSPS Overseas Research Fellowships
JSPS KAKENHI Grant Number JP19K14709
partly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds under Contracts No.FIS2017-84038-C2-1-P B and No.FIS2017-84038-C2-2-P B
funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No.824093 for the STRONG-2020 project。
