PT Journal
AU BABAR Collaboration (del Amo Sanchez, Pea
   Azzolini, V
   Lopez-March, N
   Martinez-Vidal, F
   Milanes, DA
   Oyanguren, A
TI Test of Lepton Universality in Y(1S) Decays at BABAR
SO Physical Review Letters
JI Phys. Rev. Lett.
PY 2010
BP 191801
EP 7pp
VL 104
IS 19
DI 10.1103/PhysRevLett.104.191801
LA English
AB The ratio R-tau mu(Y(1S)) = Gamma Y(1S)->tau(+)tau(-)/Gamma(+)(-)(Y(1S)->mu)(mu) is measured using a sample of (121.8 +/- 1.2) x 10(6)Y(3S) events recorded by the BABAR detector. This measurement is intended as a test of lepton universality and as a search for a possible light pseudoscalar Higgs boson. In the standard model (SM) this ratio is expected to be close to 1. Any significant deviations would violate lepton universality and could be introduced by the coupling to a light pseudoscalar Higgs boson. The analysis studies the decays Y(3S) -> Y(1S)pi(+)pi(-), Y(1S) -> l(+)l(-), where l = mu, tau. The result, R-tau μ(Y(1S)) = 1.005 +/- 0.013(stat) +/- 0.022(syst), shows no deviation from the expected SM value, while improving the precision with respect to previous measurements.
ER