Physicists rule out rare particle decays, tightening constraints on exotic physics
Using 10 billion particle collisions, researchers found no evidence for five theorized weak decay modes of the J/ψ particle, setting strict limits on how often these reactions occur. The null result constrains models of fundamental physics and guides where future experiments should focus their search for physics beyond the Standard Model.
Originaltitel: Search for J/ψ weak decays containing a <em>D</em> meson
<p>Using a sample of about 10 billion J/ψ events with the BESIII detector, we search for the weak decays of J/ψ → D<over bar><sup>0</sup>π<sup>0</sup> + c.c., J/ψ → D<over bar><sup>0</sup>η + c.c., J/ψ → D<over bar><sup>0</sup>ρ<sup>0</sup> + c.c., J/ψ → D<sup>-</sup>π<sup>+</sup> + c.c., and J/ψ → D<sup>-</sup>ρ<sup>+</sup> + c.c., Since no significant signal is observed, we set the upper limits of the branching fractions of these decays to be <em>B</em>(J/ψ → D<over bar><sup>0</sup>π<sup>0</sup> + c.c.) < 4.7 x 10<sup>-7</sup>, <em>B</em>(J/ψ → D<over bar><sup>0</sup>η + c.c.) < 6.8 x 10<sup>-7</sup>, <em>B</em>(J/ψ → D<over bar><sup>0</sup>ρ<sup>0</sup> + c.c.) < 5.2x10<sup>-7</sup>, <em>B</em>(J/ψ → D<sup>-</sup>π<sup>+</sup> c.c.) < 7.0 x 10<sup>-8</sup>, and <em>B</em>(J/ψ → D<sup>-</sup>ρ<sup>+</sup> + c.c.) < 6.0 x 10<sup>-7</sup> at the 90% confidence level.</p>