Showing posts with label The Paper. Show all posts
Showing posts with label The Paper. Show all posts
Friday, April 26
New Subatomic Particle Detected
The BESIII collaboration have reported the observation of an anomalous line shape around ppbar mass threshold in the J/ψ→γ3(π+π-) decay, which indicates the existence of a ppbar bound state. The paper was published online in Physical Review Letters.
The proximity in mass to 2mp is suggestive of nucleon-antinucleon bound states, an idea that has a long history. Before the birth of Quark Model, a nucleon-antinucleon bound state was already proposed by Prof. E. Fermi and Prof. C. N. Yang.
There is an accumulation of evidence for anomalous behavior in the proton-antiproton system near the ppbar mass threshold, e.g., J/ψ→γppabr , J/ψ→γπ+π-η' and the proton's effective form factor determined from e+e-→ppbar, exhibiting a narrow peak or a very steep falloff around the ppbar mass threshold, which inspired many speculations and renewed the interests on the nucleon-antinucleon bound state. READ MORE...
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