Amazing stuff! Let's see whether this new particle will be confirmed.
"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."
"... A decade ago, the BESIII Collaboration at the Beijing Electron Positron Collider observed one such peak . The collaboration has now confirmed the existence of that peak. But the new data and analysis reveal that the previously observed peak is actually two peaks, suggesting the existence of a new exotic particle. ...
The researchers have now analyzed a dataset that includes 50 times more decay events than the previous one. The analysis of the larger dataset reveals a small spur—a lower secondary peak—on the left side of the main peak, a sign that it contains the signals of two particles and not one. Fitting the data, the researchers find two overlapping resonance peaks that they label X(1840) and X(1880).
This finding marks the first observation of X(1880). (The observation has a statistical significance greater than 10σ.) ..."
From the abstract:
"Using a sample of (1008 7±44)×106J/ψ events, which is about 45 times larger than that was previously analyzed, a further investigation on the J/ψ→γ3(π+π−) decay is performed. A significant distortion at 1.84GeV/c2 in the line shape of the 3(π+π−) invariant mass spectrum is observed for the first time, which could be resolved by two overlapping resonant structures, X(1840) and X(1880). The new state X(1880) is observed with a statistical significance larger than 10σ. The mass and width of X(1880) are determined to be 1882.1±1.7±0.7MeV/c2 and 30.7±5.5 ±2.4MeV, respectively, which indicates the existence of a p¯p bound state."
Evidence of a New Subatomic Particle (original news release) A signal from the decay products of a meson—a quark and an antiquark—comes from two subatomic particles and not one, as previously thought.
FIG. 3.
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