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Andrea Meucci

Publications and source records attributed to Andrea Meucci.

33 records · Page 2Linked to original sources
arXiv2011

Relativistic descriptions of quasielastic charged-current neutrino-nucleus scattering: application to scaling and superscaling ideas

The analysis of the recent experimental data on charged-current neutrino-nucleus scattering cross sections measured at MiniBooNE requires fully relativistic theoretical descriptions also accounting for the role of final state interactions. In this work we evaluate inclusive quasielastic differential neutrino cross sections within the framework of the relativistic impulse approximation. Results based on the relativistic mean field potential are compared with the ones corresponding to the relativistic Green function approach. An analysis of scaling and superscaling properties provided by both models is also presented.

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arXiv2011

A relativistic model for the non-mesonic weak decay of the ${_Λ^{12} C}$ hypernucleus

A fully relativistic finite nucleus wave-function approach to the non-mesonic weak decay of the ${_Λ^{12} C}$ hypernucleus is presented. The model is based on the calculation of the amplitudes of the tree-level Feynman diagrams for the $ΛN\to NN$ process and includes one-pion exchange and one-kaon exchange diagrams. The pseudo-scalar and pseudo-vector choices for the vertex structure are compared. Final-state interactions between each one of the outgoing nucleons and the residual nucleus are accounted for by a complex phenomenological optical potential. Initial $ΛN$ and final $NN$ short-range correlations are included by means of phenomenological correlation functions. Numerical results are presented and discussed for the total non-mesonic decay width $Γ_{nm}=Γ_n+Γ_p$, the $Γ_n/Γ_p$ ratio, the $a_Λ$ intrinsic asymmetry parameter, and the kinetic energy and angular spectra.

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arXiv2009

Relativistic descriptions of inclusive quasielastic electron scattering: application to scaling and superscaling ideas

An analysis of inclusive quasielastic electron scattering is presented using different descriptions of the final state interactions within the framework of the relativistic impulse approximation. The relativistic Green's function approach is compared with calculations based on the use of relativistic purely real mean field potentials in the final state. Both approaches lead to a redistribution of the strength but conserving the total flux. Results for the differential cross section at different energies are presented. Scaling properties are also analyzed and discussed.

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arXiv2006

Strange quark effects in electron and neutrino-nucleus quasi-elastic scattering

The role of the sea quarks to ground state nucleon properties with electroweak probes is discussed. A relativistic Green's function approach to parity violating electron scattering and a distorted-wave impulse-approximation applied to charged- and neutral-current neutrino-nucleus quasi-elastic scattering are presented in view of the possible determination of the strangeness content of the nucleon.

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arXiv2006

Neutrino-nucleus quasi-elastic scattering and strange quark effects

A relativistic distorted-wave impulse-approximation model is applied to quasi-elastic neutrino-nucleus scattering. The bound state is obtained in the framework of the relativistic mean field theory and the final state interaction is taken into account in the scattering state. Results for the charged- and neutral-current neutrino (antineutrino) reactions on $^{12}$C target nucleus are presented and the sensitivity of various quantities to the strange quark content of the nucleon weak current is discussed.

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arXiv2005

Relativistic Green's function approach to parity-violating quasielastic electron scattering

A relativistic Green's function approach to parity-violating quasielastic electron scattering is presented. The components of the hadron tensor are expressed in terms of the single particle Green's function, which is expanded in terms of the eigenfunctions of the non-Hermitian optical potential, in order to account for final state interactions without any loss of flux. Results for $^{12}$C, $^{16}$O, and $^{40}$Ca are presented and discussed. The effect of the strange quark contribution to the nuclear current is investigated.

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arXiv2005

Relativistic approach to neutrino-nucleus quasielastic scattering

A relativistic Green's function and a distorted-wave impulse-approximation approach to charged- and neutral-current neutrino-nucleus quasielastic scattering are developed. Results for the neutrino (antineutrino) reactions on $^{16}$O and $^{12}$C target nuclei are presented and discussed.

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arXiv2004

Neutral-current neutrino-nucleus quasielastic scattering

A relativistic distorted-wave impulse-approximation model to quasielastic neutral-current neutrino-nucleus scattering is developed, using the relativistic mean field theory for the bound state and taking into account the final state interaction in the relativistic scattering state. Results for the neutrino (antineutrino) reaction on 12C target nucleus are presented in an energy range between 500 and 1000 MeV. The sensitivity to the strange quark content of the axial-vector form factor is discussed.

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arXiv2003

Relativistic approach to (e,e'p) and (e,e') reactions

A relativistic distorted wave impulse approximation model for electron-induced one proton knockout reactions and a Green's function approach to inclusive scattering are developed. Results for (e,e'p) and (e,e') reactions are presented in various kinematical conditions and compared (when possible) with nonrelativistic calculations.

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arXiv2003

Relativistic Green's function approach to charged-current neutrino-nucleus quasielastic scattering

A relativistic Green's function approach to inclusive quasielastic charged-current neutrino-nucleus scattering is developed. The components of the hadron tensor are written in terms of the single-particle Green's function, which is expanded on the eigenfunctions of the nuclear optical potential, so that final state interactions are accounted for by means of a complex optical potential but without a loss of flux. Results for the (neutrino_mu, mu-) reaction on 16O and 12C target nuclei are presented and discussed. A reasonable agreement of the flux-averaged cross section on 12C with experimental data is achieved.

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arXiv2003

Inclusive electron scattering in a relativistic Green function approach

A relativistic Green function approach to the inclusive quasielastic (e,e') scattering is presented. The single particle Green function is expanded in terms of the eigenfunctions of the nonhermitian optical potential. This allows one to treat final state interactions consistently in the inclusive and in the exclusive reactions. Numerical results for the response functions and the cross sections for different target nuclei and in a wide range of kinematics are presented and discussed in comparison with experimental data.

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arXiv2002

Relativistic approach to one nucleon knockout reactions

We develop a fully relativistic distorted wave impulse approximation model for electron- and photon-induced one proton knockout reactions. The relativistic mean field for the bound state and the Pauli reduction for the scattering state are used, including a fully relativistic electromagnetic current operator. Results for 16O(e,e'p) cross section and structure functions are shown in various kinematic conditions and compared with nonrelativistic calculations. Nuclear transparency calculations in a Q^2 range between 0.3 and 1.8 (GeV/c)^2 are presented. Results for 16O(gamma,p) differential cross sections are displayed in an energy range between 60 and 150 MeV including two-body seagull contribution in the nuclear current.

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arXiv2002

Meson exchange currents in a relativistic model for electromagnetic one nucleon emission

We analyze the role of meson exchange currents (MEC) in photon- and electron-induced one nucleon emission reactions in a fully relativistic model. The relativistic mean field theory is used for the bound state and the Pauli reduction for the scattering state. Direct 1-body and exchange 2-body terms in the nuclear current are considered. Results for the 12C(gamma,p) and 16O(gamma,p) differential cross sections and photon asymmetries are displayed in an energy range between 60 and 196 MeV. The 2-body seagull current affects the cross section less than in nonrelativistic analyses. In the case of the 16O(gamma,n) differential cross section MEC effects are large but not sufficient to reproduce the data. MEC have a small effect on (e,e'p) calculations.

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arXiv2001

Relativistic calculation of nuclear transparency in (e,e'p) reactions

Nuclear transparency in (e,e'p) reactions is evaluated in a fully relativistic distorted wave impulse approximation model. The relativistic mean field theory is used for the bound state and the Pauli reduction for the scattering state, which is calculated from a relativistic optical potential. Results for selected nuclei are displayed in a Q^2 range between 0.3 and 1.8 (GeV/c)^2 and compared with recent electron scattering data. For Q^2 = 0.3 (GeV/c)^2 the results are lower than data; for higher Q^2 they are in reasonable agreement with data. The sensitivity of the model to different prescriptions for the one-body current operator is investigated. The off-shell ambiguities are rather large for the distorted cross sections and small for the plane wave cross sections.

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