Publications

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Unexpected high-energy γ emission from decaying exotic nuclei

A. Gottardo, D. Verney, I. Deloncle, S. Péru, C. Delafosse, S. Roccia, I. Matea, C. Sotty, C. Andreoiu, C. Costache, M.-C. Delattre, A. Etilé, S. Franchoo, C. Gaulard, J. Guillot, F. Ibrahim, M. Lebois, M. MacCormick, N. Marginean, R. Marginean, M. Martini, C. Mihai, I. Mitu, L. Olivier, C. Portail, L. Qi, B. Roussière, L. Stan, D. Testov, J. Wilson, D.T. Yordanov

The N = 52 83Ga β decay was studied at ALTO. The radioactive 83Ga beam was produced through the ISOL photofission technique and collected on a movable tape for the measurement of γ -ray emission following β decay. While β-delayed neutron emission has been measured to be 56–85% of the decay path, in this experiment an unexpected high-energy 5–9 MeV γ -ray yield of 16(4)% was observed, coming from states several MeVs above the (...)

Narrow exotic tetraquark mesons in large-N_c QCD

Hagop Sazdjian

Discussing four-point Green functions of bilinear quark currents in large-N_c QCD, we formulate rigorous criteria for selecting diagrams appropriate for the analysis of potential tetraquark poles. We find that both flavor-exotic and cryptoexotic (i.e., flavor-nonexotic) tetraquarks, if such poles exist, have a width of order O(1/N_c^2), so they are parametrically narrower compared to the ordinary mesons, which have a width of order O(1/N_c). Moreover, for flavor-exotic states, the (...)

Delta(1232) Dalitz decay in proton-proton collisions at T=1.25 GeV measured with HADES at GSI

We report on the investigation of Δ(1232) production and decay in proton-proton collisions at a kinetic energy of 1.25 GeV measured with HADES. Exclusive dilepton decay channels ppe+e− and ppe+e−γ have been studied and compared with the partial-wave analysis of the hadronic ppπ0 channel. They allow to access both Δ+→pπ0(e+e−γ) and Δ+→pe+e− Dalitz decay channels. The perfect reconstruction of the well-known π0 Dalitz decay serves as a proof of the consistency of the analysis. The Δ Dalitz decay is (...)

Lee-Yang–inspired functional with a density-dependent neutron-neutron scattering length

M. Grasso, D. Lacroix, and C. J. Yang

Inspired by the low-density Lee-Yang expansion for the energy of a dilute Fermi gas of density ρ and momentum kF, we introduce here a Skyrme-type functional that contains only s-wave terms and provides, at the mean-field level, (i) a satisfactory equation of state for neutron matter from extremely low densities up to densities close to the equilibrium point, and (ii) a good-quality equation of state for symmetric matter at density scales around (...)