quasi-physical bases, corresponding to the four normalized gaugino-higgsino-Higgs couplings, $\hat f_U^a$, $\hat f_D^a$, $\hat f_U^{\prime\,a}$ and $\hat f_D^{\prime\,a}$. Each basis is defined by imposing the condition that one of the two components of the corresponding coupling vanishes, while setting the non-vanishing component to unity. This defines the quasi-physical basis up to an arbitrary rephasing of the Higgs field that lies in the direction of the vanishing component of $f$. The latter is a pseudo-invariant field, whereas the Higgs field that lies in the direction of the non-vanishing component of $f$ is a U(2)-invariant field.[^10]

The four quasi-physical bases and their corresponding Higgs fields are: \_U: &&  f\_U\^a=(0,1),:  (\_U, H\_U),\[bu\]\
\_D: &&  f\_D\^a=(1,0),:  (H\_D, \_D),\[bd\]\
\^\_U: && f\^[a]{}\_U=(0,1),:  (\^\_U,H\^\_U),\[bup\]\
\^\_D: && f\^[a]{}\_D=(1,0),:  (H\^\_D,\^\_D),\[bdp\] where the fields denoted by (calligraphic) Roman fonts are (pseudo-)invariant with respect to U(2) basis transformations. The Higgs fields with a $U$ ($D$) subscript are hypercharge $+1$ ($-1$) fields. The coefficients of the scalar potential in the quasi-physical basis are easily constructed. For example, in basis $\mathcal{B}_D$, Y\_[D1]{}&& f\_D\^[a]{} f\_D\^b Y\_[ab]{}, Y\_[D2]{}g\_D\^[a]{} g\_D\^b Y\_[ab]{},\[cov1\]\
Y\_[D3]{}&&f\_D\^[a]{} g\_D\^b Y\_[ab]{}, Z\_[D1]{}f\_D\^[a]{} f\_D\^b f\_D\^[c]{} f\_D\^d Z\_[abcd]{},\[cov2\]\
Z\_[D2]{}&& g\_D\^[a]{} g\_D\^b g\_D\^[c]{} g\_D\^d Z\_[abcd]{},Z\_[D3]{}f\_D\^[a]{} f\_D\^b g\_D\^[c]{} g\_D\^d Z\_[abcd]{},\[cov3\]\
Z\_[D4]{}&& g\_D\^[a]{} f\_D\^b f\_D\^[c]{} g\_D\^d Z\_[abcd]{},Z\_[D5]{}f\_D\^[a]{} 