1.82 + 0.6007 \chi_+ + 0.4653 \chi_- + 16.49 \eta^2 + 0.9369 \chi_+ \chi_- - 0.2701 \chi_-^2 - 53.16 \eta^3 - 4.201 \eta^2 \chi_- + 2.18 \eta \chi_+^2 - 6.289 \eta \chi_+ \chi_-
equal mass adjustment:
0.2115 |\chi_-|