Particle physicists find no exotic behavior in antimatter collision experiment
Researchers at China's BESIII detector measured subatomic particle collisions with record precision but found no anomalous threshold effects—closing off one theoretical possibility for exotic matter. The null result, while scientifically valuable for ruling out certain models, has limited immediate commercial implications but advances fundamental physics understanding.
Originaltitel: Measurement of the <em>e</em><sup>+</sup><em>e</em><sup>-</sup> → <em>p</em><em>p<</em>over-bar>π<sup>0</sup> cross section at √<em>s</em>=2.1000-3.0800 GeV
<p>The process e<sup>+</sup>e<sup>-</sup> → <em>pp<over bar>π<sup>0</sup></em> is studied at 20 center-of-mass energies ranging from 2.1000 to 3.0800 GeV using 636.8 pb<sup>-1</sup> of data collected with the BESIII detector operating at the BEPCII collider. The Born cross sections for e<sup>+</sup>e<sup>-</sup> → <em>pp<over bar>π<sup>0</sup></em> are measured with high precision. Since the lowest center-of-mass energy, 2.1000 GeV, is less than 90 MeVabove the <em>pp<over bar>π<sup>0</sup></em> energy threshold, we can probe the threshold behavior for this reaction. However, no anomalous threshold enhancement is found in the cross sections for e<sup>+</sup>e<sup>-</sup> → <em>pp<over bar>π<sup>0</sup></em>.</p>