The isospin-violating J/ψ→ΛΛ̄π⁰ decay is shown to selectively produce the dynamically-generated Σ(1430) resonance while suppressing the conventional Σ(1385) state, matching limited BESIII data.
Measurement of the Sigma pi photoproduction line shapes near the Lambda(1405)
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abstract
The reaction gamma + p -> K+ + Sigma + pi was used to determine the invariant mass distributions or "line shapes" of the Sigma+ pi-, Sigma- pi+ and Sigma0 pi0 final states, from threshold at 1328 MeV/c^2 through the mass range of the Lambda(1405) and the Lambda(1520). The measurements were made with the CLAS system at Jefferson Lab using tagged real photons, for center-of-mass energies 1.95 < W < 2.85 GeV. The three mass distributions differ strongly in the vicinity of the I=0 \Lambda(1405), indicating the presence of substantial I=1 strength in the reaction. Background contributions to the data from the Sigma0(1385) and from K^* Sigma production were studied and shown to have negligible influence. To separate the isospin amplitudes, Breit-Wigner model fits were made that included channel-coupling distortions due to the NKbar threshold. A best fit to all the data was obtained after including a phenomenological I=1, J^P = 1/2^- amplitude with a centroid at 1394\pm20 MeV/c^2 and a second I=1 amplitude at 1413\pm10 MeV/c^2. The centroid of the I=0 Lambda(1405) strength was found at the Sigma pi threshold, with the observed shape determined largely by channel-coupling, leading to an apparent overall peak near 1405 MeV/c^2.
fields
hep-ph 2representative citing papers
Hadronic molecules serve as a framework for certain exotic heavy-quark states where nonrelativistic effective field theories enable predictions with controlled uncertainty.
citing papers explorer
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Role of the $\Sigma(1430)(1/2^-)$ in the $J/\psi \to \Lambda \bar{\Lambda} \pi^0$ reaction
The isospin-violating J/ψ→ΛΛ̄π⁰ decay is shown to selectively produce the dynamically-generated Σ(1430) resonance while suppressing the conventional Σ(1385) state, matching limited BESIII data.
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Hadronic molecules
Hadronic molecules serve as a framework for certain exotic heavy-quark states where nonrelativistic effective field theories enable predictions with controlled uncertainty.