José Enrique García Navarro

Magnetic susceptibility of neutron matter in a relativistic σ+ω+π+ϱ Hartree-Fock approach

Abstract A relativistic Hartree-Fock approach is used to study the magnetic susceptibility of a pure neutron system at relevant densities in neutron stars. Several combinations of mesons and couplings are used. The inclusion of isovector mesons crucially determines the possibility of a ferromagnetic transition. A π-meson pseudoscalar coupling favours the ferromagnetic phase whilst the pseudovector one inhibits it.

Measurement of the Lambda_b lifetime and mass in the ATLAS experiment

Aad, G.; et al., [Unknown]; Aben, R.; Beemster, L.J.; Bentvelsen, S.; Berglund, E.; Bobbink, G.J.; Bos, K.; Boterenbrood, H.; Colijn, A.P.; de Jong, P.; de Nooij, L.; Deluca, C.; Deviveiros, P.O.; Doxiadis, A.D.; Ferrari, P.; Garitaonandia, H.; Geerts, D.A.A.; Gosselink, M.; Hartjes, F.; Hessey, N.P.; Igonkina, O.; Kayl, M.S.; Klous, S.; Kluit, P.; Koffeman, E.; Lee, H.; Lenz, T.; Linde, F.; Luijckx, G.; Massaro, G.; Mechnich, J.; Mussche, I.; Ottersbach, J.P.; Pani, P.; Rijpstra, M.; Ruckstuhl, N.; Ta, D.; Tsiakiris, M.; Turlay, E.; van der Deijl, P.C.; van der Geer, R.; van der Graaf, H.; van der Leeuw, R.; van der Poel, E.; van Vulpen, I.; Verkerke, W.; Vermeulen, J.C.; Vranjes Milosavljevic, M.; Vreeswijk, M.A measurement of the Λb lifetime and mass in the decay channel Λ 0 b → J/ψ(μ+μ−)Λ0(pπ−) is presented. The analysis uses a signal sample of about 2200 Λb and Λ̄ 0 b decays that are reconstructed in 4.9 fb −1 of ATLAS pp collision data collected in 2011 at the LHC center-of-mass energy of 7 TeV. A simultaneous mass and decay time maximum likelihood fit is used to extract the Λb lifetime and mass. They are measured to be τΛb = 1.449± 0.036(stat)± 0.017(syst) ps and mΛb = 5619.7± 0.7(stat)± 1.1(syst) MeV. ar X iv :1 20 7. 22 84 v3 [ he pex ] 2 0 A pr 2 01 3 Measurement of the Λ0b lifetime and mass in the ATLAS experiment The ATLAS Collaboration (Dated: May 2, 2014) A measurement of the Λb lifetime and mass in the decay channel Λ 0 b → J/ψ(μ+μ−)Λ0(pπ−) is presented. The analysis uses a signal sample of about 2200 Λb and Λ̄ 0 b decays that are reconstructed in 4.9 fb−1 of ATLAS pp collision data collected in 2011 at the LHC center-of-mass energy of 7 TeV. A simultaneous mass and decay time maximum likelihood fit is used to extract the Λb lifetime and mass. They are measured to be τΛb = 1.449± 0.036(stat)± 0.017(syst) ps and mΛb = 5619.7± 0.7(stat)± 1.1(syst) MeV.