A template method to measure the $$t {\bar{t}}$$ polarisation

AbstractWe develop a template method for the measurement of the polarisation of $$t {\bar{t}}$$ t t ¯ pairs produced in hadron collisions. The method would allow to extract the individual fractions of $$t_L \bar{t}_L$$ t L t ¯ L , $$t_R {\bar{t}}_R$$ t R t ¯ R , $$t_L {\bar{t}}_R$$ t L t ¯ R and $$t_R {\bar{t}}_L$$ t R t ¯ L pairs with a fit to data, where L, R refer to the polarisation along any axis. These polarisation fractions have not been independently measured at present. Secondarily, the method also provides the net polarisation of t and $${\bar{t}}$$ t ¯ , as well as their spin correlation for arbitrary axes.