In a paper to be published in Science on 22 September, the Pierre Auger Collaboration reports observational evidence demonstrating that cosmic rays with energies a million times greater than that of the protons accelerated in the Large Hadron (...)
Dans le cadre de la conférence grand public qui s’est déroulée au CERN le 29 juin dernier, retrouvez les présentations et interviews d’Hélène Langevin. A voir également : Le jour où j’ai rencontré la petitefille de Marie Curie Photo: © graine de genie graine de citoyen 2017 Vidéo: © 2017 CERN
An international team led by scientists from IPN Orsay (CNRS/Université ParisSud), CEA, and RIKEN (Japan) has performed the first spectroscopy of the extremely neutronrich isotopes 98,100Kr. This experiment showed that there are two coexisting, competing quantum shapes at low energy in 98Kr, (...)
Measurements of the mass and charge distributions of isotopes, produced when a heavy nucleus fissions into two lighter fragments, are important for several reasons. These include understanding the complex phenomenon of fission itself, the (...)
J.N. Wilson, M. Lebois, L. Qi, et al.
Discussing fourpoint Green functions of bilinear quark currents in largeN_c QCD, we formulate rigorous criteria for selecting diagrams appropriate for the analysis of potential tetraquark poles. We find that both flavorexotic and cryptoexotic (i.e., flavornonexotic) 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 flavorexotic states, the (...)
Hagop Sazdjian
We report on the investigation of Δ(1232) production and decay in protonproton 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 partialwave 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 wellknown π0 Dalitz decay serves as a proof of the consistency of the analysis. The Δ Dalitz decay is (...)
Inspired by the lowdensity LeeYang expansion for the energy of a dilute Fermi gas of density ρ and momentum kF, we introduce here a Skyrmetype functional that contains only swave terms and provides, at the meanfield 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 goodquality equation of state for symmetric matter at density scales around (...)
M. Grasso, D. Lacroix, and C. J. Yang
Phenomenological effective interactions like Skyrme forces are currently used in meanfield calculations in nuclear physics. Meanfield models have strong analogies with the first order of the perturbative manybody problem and the currently used effective interactions are adjusted at the meanfield level. In this work, we analyze the renormalizability of the nuclear manybody problem in the case where the effective Skyrme interaction is employed in (...)
C. J. Yang, M. Grasso, K. Moghrabi, and U. van Kolck
We analyze the power counting of the peripheral singlet partial waves in nucleonnucleon scattering. In agreement with conventional wisdom, we find that pion exchanges are perturbative in the peripheral singlets. We quantify from the effective field theory perspective the wellknown suppression induced by the centrifugal barrier in the pionexchange interactions. By exploring perturbation theory up to fourth order, we find that the onepionexchange (...)
M. Pavón Valderrama, M. Sánchez Sánchez, C.J. Yang, Bingwei Long, J. Carbonell, and U. van Kolck
We further progress along the line of Ref. [D. Lacroix, Phys. Rev. A 94, 043614 (2016)] where a functional for Fermi systems with anomalously large swave scattering length as was proposed that has no free parameters. The functional is designed to correctly reproduce the unitary limit in Fermi gases together with the leadingorder contributions in the s and pwave channels at low density. The functional is shown to be predictive up (...)
Denis Lacroix, Antoine Boulet, Marcella Grasso, and C.J. Yang
Abstract We report on the βdelayed neutron emission probability (P1n) measurements of the 82,83,84Ga (N=51,52,53) precursors performed in one single experiment using the 3He neutroncounter TETRA at the ALTO facility in Orsay. Altogether our results for the three A=82,83, and 84 Ga precursors point towards a sizable P1n staggering in the N=50 region, similar to the one already observed just after the N=28 shell closure in the K isotopes chain, hinting at a similar mechanism. We will (...)
D. Verney, D. Testov, F. Ibrahim, B. Roussière, S. Franchoo, R. Li, I. Matea, I. Stefan, and D. Suzuki
Institut de Physique Nucléaire Orsay  15 rue Georges CLEMENCEAU  91406 ORSAY (FRANCE) 



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