A dipole resonance of 11Li is found by a 9Li + n + n three-body model analysis with the complexscaling method. The resonance can be interpreted as a bound state in the 10Li + n system, i.e., a Feshbach resonance in the 9Li + n + n system. As a characteristic feature of the Feshbach resonance of 11Li, the 10Li + n threshold is open above the 9Li + n + n one, which reflects a distinctive property of the Borromean system.A microscopic four-body reaction calculation for the 11Li(p,p) reaction at 6 MeV/nucleon is performed by taking into account the resonant and nonresonant continuum states of the three-body system. The calculation of angular distributions of the elastic and inelastic scattering as well as the energy spectrum reproduced a recent experimental result. Furthermore, the E1 strength distribution from a Coulomb dissociation experiment was also reproduced in this framework. This means that the existence of the Borromean Feshbach resonance may consistently answer a long-standing open question of an excited state of 11Li.
All Science Journal Classification (ASJC) codes