content_image/350348.jpg content_image/350347.jpg content_image/350346.jpg content_image/350345.jpg
Perturbing away from the limit of exact degeneracy gives corrections to these expressions of O (( µ$_{S}$ − µ$_{D}$ ) /µ$_{D}$ ). Note we have assumed that there is no CP violation for simplicity. In order to apply these expressions to the MSSM one can make the identifications 

<img src='content_image/350348.jpg'>

where we neglect terms of O (1 /M$_{2}$ ) for the Bino/Higgsino system and O (1 /M$_{1}$ ) for the Wino/Higgsino system. 

Explicitly making the substitutions for the MSSM we have 

<img src='content_image/350347.jpg'>

and 

<img src='content_image/350346.jpg'>

## Appendix C: No-go Theorem for photino-Higgsino DM 

The neutralino mass matrix in the (˜ γ, ˜ Z, ˜ H$_{d}$, ˜ H$_{u}$ ) basis is given by 

<img src='content_image/350345.jpg'>

Is it possible to generate a large SD/SI ratio by having DM which is only a mixture of photino and Higgsino? The Higgsino component is required for a non-trivial coupling to the Z 0 and an admixture of photino (and not Zino) will allow ( | Z$_{H}$$_{d}$ | 2 − | Z$_{H}$$_{u}$ | $^{2}$) ̸ = 0 without introducing 

