Journal of High Energy Physics Journal of High Energy Physics, 2015, 09, pp.49. ⟨10.1007/JHEP09(2015)049⟩ Journal of High Energy Physics, Springer, 2015, 49, ⟨10.1007/JHEP09(2015)049⟩ Journal of high energy physics 2015(9), 49 (2015). doi:10.1007/JHEP09(2015)049