SSA vs. z

Asymmetries are defined as (Y,B):

Yellow Beam: -1 x { (__++__ + __+-__) - (__-+__ + __--__) }
Blue Beam: -1 x { (__++__ + __-+__) - (__+-__ + __--__) }
Like-Sign: (__++__) - (__--__)
Unlike-Sign: (__+-__) - (__-+__)

More details at this blog post