2010/02/28 by The BABAR Collaboration, J. P. Lees, P. del Amo Sanchez +98 · 1 citation
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #hep-ex
paper · pdf · doi:10.1103/physrevlett.104.191801
published as Phys.Rev.Lett.104:191801,2010 · 7 pages, 3 figures
openalex publication_date 2010/05/14 · arxiv created 2010/05/17 · arxiv updated 2010/05/25 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
The ratio R_\ensuremathτ\ensuremathμ(\ensuremathΥ(1S))=\ensuremathΓ_\ensuremathΥ(1S)\ensuremath→\ensuremathτ+\ensuremathτ^\ensuremath-/\ensuremathΓ_\ensuremathΥ(1S)\ensuremath→\ensuremathμ+\ensuremathμ^\ensuremath- is measured using a sample of (121.8\ifmmode±\else\textpm\fi1.2)\ifmmode×\else\texttimes\fi106\ensuremathΥ(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 \ensuremathΥ(3S)\ensuremath→\ensuremathΥ(1S)\ensuremathπ+\ensuremathπ^\ensuremath-, \ensuremathΥ(1S)\ensuremath→l+l^\ensuremath-, where l=\ensuremathμ, \ensuremathτ. The result, R_\ensuremathτ\ensuremathμ(\ensuremathΥ(1S))=1.005\ifmmode±\else\textpm\fi0.013(stat)\ifmmode±\else\textpm\fi0.022(syst), shows no deviation from the expected SM value, while improving the precision with respect to previous measurements.