Fig. 5

(a) Energy plotted as a function of momentum and for various values of the anisotropy r. Both the branches of matter, E+(p), and antimatter, │E−│(p), are shown. (b) Locus of momentum \({p_{\hbox{min} }}(r)\) and energy \({\left| {{E_ - }} \right|_{\hbox{min} }}(r)\), corresponding to the energy minimum for the antimatter, plotted for all 0 ≤ r ≤ 2.