120314857
Latent heat of nuclear matter
We study the latent heat of the liquid-gas phase transition in symmetric nuclear matter using self-consistent mean-field calculations with a few Skyrme forces. The temperature dependence of the latent heat is rather independent of the mean-field parametrization and it can be characterized by a few parameters. At low temperatures, the latent heat tends to the saturation energy. Near the critical point, the latent heat goes to zero with a well-determined mean-field critical exponent. A maximum value of the latent heat in the range l similar to 25-30 MeV is found at intermediate temperatures, which might have experimental relevance. All these features can be explained from very basic principles.
17099587
Self-consistent Green's functions formalism with three-body interactions
We extend the self-consistent Green's functions formalism to take into account three-body interactions. We analyze the perturbative expansion in terms of Feynman diagrams and define effective one- and two-body interactions, which allows for a substantial reduction of the number of diagrams. The procedure can be taken as a generalization of the normal ordering of the Hamiltonian to fully correlated density matrices. We give examples up to third order in perturbation theory. To define nonperturbative approximations, we extend the equation of motion method in the presence of three-body interactions. We propose schemes that can provide nonperturbative resummation of three-body interactions. We also discuss two different extensions of the Koltun sum rule to compute the ground state of a many-body system.
126243169
The selection crate for the L0 calorimeter trigger
116891509
Status and Future Perspectives on the Measurement of the Unitarity Triangle Angle α
A summary on the status of the measurements of the Unitarity Triangle angle α using the decays B → ππ, B → ρπ and B → ρρ and on the future perspectives at the Large Hadron Collider experiment LHCb is presented. The UTfit collaboration, combining the BABAR measurements from B → ρπ and B → ρρ, give as Standard Model solution the value α = (106 ± 8)°. The LHCb Collaboration has estimated the sensitivity on α from the B0 → ρπ decay obtaining a relative error σαα ⩽ 0.1, in one nominal year of data taking.
118666057
Tensor force effects and high-momentum components in the nuclear symmetry energy
We analyze microscopic many-body calculations of the nuclear symmetry energy and its density dependence. The calculations are performed in the framework of the Brueckner-Hartree-Fock and the self-consistent Green’s functions methods. Within Brueckner-Hartree-Fock, the Hellmann-Feynman theorem gives access to the kinetic energy contribution as well as the contributions of the different components of the nucleon-nucleon interaction. The tensor component gives the largest contribution to the symmetry energy. The decomposition of the symmetry energy in a kinetic part and a potential energy part provides physical insight on the correlated nature of the system, indicating that neutron matter is less correlated than symmetric nuclear matter. Within the self-consistent Green’s function approach, we compute the momentum distributions and we identify the effects of the high momentum components in the symmetry energy. The results are obtained for the realistic interaction Argonne V18 potential, supplemented by the Urbana IX three-body force in the Brueckner-Hartree-Fock calculations.
110405827
Storage management solutions and performance tests at the INFN Tier-1
Performance, reliability and scalability in data access are key issues in the context of HEP data processing and analysis applications. In this paper we present the results of a large scale performance measurement performed at the INFN-CNAF Tier-1, employing some storage solutions presently available for HEP computing, namely CASTOR, GPFS, Scalla/Xrootd and dCache. The storage infrastructure was based on Fibre Channel systems organized in a Storage Area Network, providing 260 TB of total disk space, and 24 disk servers connected to the computing farm (280 worker nodes) via Gigabit LAN. We also describe the deployment of a StoRM SRM instance at CNAF, configured to manage a GPFS file system, presenting and discussing its performances.
199685274
Observation of overlapping spin-1 and spin-3 $\overline{D}^0 K^-$ resonances at mass $2.86 {\rm GeV}/c^2$