Ab initio NCSMC for three-cluster systems and application to 6He

The \emph{Ab initio} no-core shell model/resonating group method (NCSM/RGM) introduced in Ref. [1] is a technique able to describe both structure and reactions in light nuclear systems. This approach combines a microscopic cluster technique with the use of realistic inter-nucleon interactions and a consistent microscopic description of the nucleon clusters. In Refs.[2,3], we introduced the treatment of three-body cluster dynamics, making the approach suitable for the investigation of systems presenting such structure and presented results for $^6$He within a $^4$He(g.s.)+$n$+$n$ basis. In this work, we go a step further and include short-range correlations by means of the no-core shell model with continuum (NCSMC), which couples the NCSM/RGM continuous cluster basis with the A-body NCSM discrete basis. We find that these correlations play an important role in the structure of the $^6$He ground state and 2$^+_1$ resonance. We will present results for $^6$He ground and continuum states as well as initial results for the $^5$H unbound nucleus within a $^3$H+$n$+$n$ basis. [1] S. Quaglioni and P. Navr\'atil, PRL 101, 092501 (2008). [2] S. Quaglioni, C. Romero-Redondo, P. Navr\'atil, PRC 88, 034320 (2013). [3] CRR, S. Quaglioni, P. Navr\'atil and G. Hupin. PRL 113, 032503 (2014)