The angular distributions of muons from Upsilon(1S,2S,3S) mu+ mu- decays are measured using data from pp collisions at sqrt[s] = 1.96TeV corresponding to an integrated luminosity of 6.7fb(-1) and collected with the CDF II detector at the Fermilab Tevatron. This analysis is the first to report the full angular distributions as functions of transverse momentum p(T) for Upsilon mesons in both the Collins-Soper and s-channel helicity frames. This is also the first measurement of the spin alignment of Upsilon(3S) mesons. Within the kinematic range of Upsilon rapidity |y|<0.6 and p(T) up to 40GeV/c, the angular distributions are found to be nearly isotropic.
Measurements of the angular distributions of muons from Upsilon decays in pp collisions at sqrt[s] = 1.96TeV.
DELL'ORSO, MAURO;DONATI, SIMONE;PUNZI, GIOVANNI;
2012-01-01
Abstract
The angular distributions of muons from Upsilon(1S,2S,3S) mu+ mu- decays are measured using data from pp collisions at sqrt[s] = 1.96TeV corresponding to an integrated luminosity of 6.7fb(-1) and collected with the CDF II detector at the Fermilab Tevatron. This analysis is the first to report the full angular distributions as functions of transverse momentum p(T) for Upsilon mesons in both the Collins-Soper and s-channel helicity frames. This is also the first measurement of the spin alignment of Upsilon(3S) mesons. Within the kinematic range of Upsilon rapidity |y|<0.6 and p(T) up to 40GeV/c, the angular distributions are found to be nearly isotropic.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.