TY - JOUR
T1 - Observation of the Anomalous Shape of X (1840) in J/ψ →γ3 (π+π-) Indicating a Second Resonance Near p p ¯ Threshold
AU - BESIII Collaboration
AU - Ablikim, M.
AU - Achasov, M. N.
AU - Adlarson, P.
AU - Ai, X. C.
AU - Aliberti, R.
AU - Kalantar-Nayestanaki, N.
AU - Kavatsyuk, M.
AU - Messchendorp, J.
PY - 2024/4/12
Y1 - 2024/4/12
N2 - Using a sample of (10087±44)×106 J/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 1.84 GeV/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±0.7 MeV/c2 and 30.7±5.5±2.4 MeV, respectively, which indicates the existence of a pp¯ bound state.
AB - Using a sample of (10087±44)×106 J/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 1.84 GeV/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±0.7 MeV/c2 and 30.7±5.5±2.4 MeV, respectively, which indicates the existence of a pp¯ bound state.
U2 - 10.1103/PhysRevLett.132.151901
DO - 10.1103/PhysRevLett.132.151901
M3 - Article
SN - 0031-9007
VL - 132
JO - Physical Review Letters
JF - Physical Review Letters
IS - 15
M1 - 151901
ER -