Speaker
Ms
Elisa Guido
(INFN & University Genova)
Description
A selection of electroweak measurements performed by the BaBar experiment operating at the Stanford Linear Accelerator Center is presented.
Using a sample of 122 million Y(3S) decays, we measure the ratio
R = BR(Y(1S) -> tautau)/BR(Y(1S) -> mumu); the
measurement is intended as a test of the lepton universality and
as a search for a light pseudoscalar Higgs boson in NMSSM
scenarios. Such a boson could appear in a deviation of the ratio
R from 1. The analysis exploits the decays Y(3S) -> Y(1S)pi+pi-,
Y(1S) -> l+l-, where l=mu,tau.
We also present a search for the non-conservation of lepton flavor in the
decay tau -> mu/e gamma performed with 967 M tau decays from e+e-
annihilations at a center-of-mass energy corresponding to Y(2S), Y(3S) and
Y(4S) resonances.
Two additional results are based only on data recorded by BaBar at the Y(4S) resonance.
The first result is a precision measurement of the mass of the
tau lepton using 423 fb-1 of data. Using a pseudomass endpoint method, we determine
the tau mass and we also measure the mass difference between the tau+
and tau-. Finally, precise measurements of the tau- -> KS0 pi- (pi0) nu_tau branching
fraction and hadronic mass distribution are made using ~ 384 fb-1 of
data. The mass and width of K*(892)- meson
are found to be significantly different from PDG averages from
those found in hadroproduction but are consistent with the recent
measurements made by Belle using the same tau decay mode as
considered here.
Primary author
Ms
Elisa Guido
(INFN & University Genova)
