Physicists rule out rare particle decay, narrowing laws of nature
Researchers found no evidence for exotic decays of subatomic particles that would violate known symmetries in physics. The discovery tightens constraints on beyond-standard-model physics and validates current theoretical frameworks—important for directing future particle research investments and validating detector technologies used across high-energy physics experiments.
Originaltitel: Search for the isospin-violating decays 𝜒𝑐𝐽→Λ¯Σ 0+c.c. and 𝜂𝑐→Λ¯Σ 0+c.c
<p>Using a sample of (2712.4 +/- 14.3) x 10(6) psi(3686) events collected with the BESIII detector, we perform a search for the isospin-violating decays chi(cJ) -> Lambda(Sigma) over bar (0) + c.c. (J = 0, 1, 2) and eta(c) -> Lambda(Sigma) over bar (0) + c.c. thorn c:c. No significant signal for chi(cJ) or eta(c) is observed in the Lambda(Sigma) over bar (0) invariant mass distribution. The upper limits on the branching fractions at the 90% confidence level are set to be B(chi(c0) -> Lambda(Sigma) over bar (0) + c.c.) < 1.5 x 10(-6), B(chi(c1) -> Lambda<(Sigma)over bar>(0) + c.c.) < 1.6 x 10(-6), B(chi(c2) -> Lambda<(Sigma)over bar>(0) + c.c.) < 1.7 x 10(-6), and B(eta(c) -> Lambda<(Sigma)over bar>(0) + c.c.) < 6.2 x 10(-5) for the first time.</p>