Physicists set new limits on rare particle decay, constraining fundamental physics
Researchers at China's BESIII detector found no evidence for two exotic decay pathways of the D* particle, setting the most stringent limits to date. The null result refines theoretical models of particle physics and helps guide where physicists should focus billion-dollar experiments searching for physics beyond the standard model.
Originaltitel: Search for the leptonic decays 𝐷*<sup>+</sup> →𝑒<sup>+</sup>𝜈<sub>𝑒</sub> and 𝐷*<sup>+</sup> →𝜇<sup>+</sup>𝜈<sub>𝜇</sub>
<p>We present the first search for the leptonic decays D*(+) -> e(+)v(e) and D*(+) -> mu(+)v(mu) by analyzing a data sample of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, corresponding to an integrated luminosity of 6.32 fb(-1). No significant signal is observed. The upper limits on the branching fractions for D*(+) -> e(+)v(e) and D*(+) -> mu(+)v(mu) are set to be 1.1 x 10(-5) and 4.3 x 10(-6) at 90% confidence level, respectively.</p>