s - and d -wave intruder strengths in Bg.s.13 via the H1(B13,d)B12 reaction

Experimental results of the $^{1}\mathrm{H}(^{13}\mathrm{B},d)^{12}\mathrm{B}$ transfer reaction to the low-lying states in $^{12}\mathrm{B}$ are reported. The optical potential parameters for the entrance channel are extracted from the elastic scattering $^{1}\mathrm{H}(^{13}\mathrm{B},\phantom{\rule{0.16em}{0ex}}p)$ measured in the same experiment, while those for the exit channel are global ones. Spectroscopic factors associated with the $p$-, $s$-, and $d$-wave neutron transfer to the known $^{12}\mathrm{B}$ states are extracted by comparing the deuteron angular distributions with the calculation results. The separated $s$- and $d$-wave intruder strengths in $^{13}\mathrm{B}_{\mathrm{g}.\mathrm{s}.}$ were determined to be $5(2)%$ and $12(2)%$, respectively, which follow roughly the systematics for the $N=8$ neutron-rich isotones and shell model calculations with YSOX interaction. The sudden change of the intruder $sd$-wave intensity between $^{13}\mathrm{B}$ and $^{12}\mathrm{Be}$ needs further theoretical interpretation.