Measurements of the angular distributions of muons from Υ decays in pp collisions at sqrt[s] = 1.96 TeV.
Aaltonen T, Álvarez González B, Amerio S, Amidei D, Anastassov A, Annovi A, Antos J, Apollinari G, Appel JA, Arisawa T, et al. Phys Rev Lett. 2012 Apr 13; 108(15):151802. Epub 2012 Apr 11.