Hadronic Decays of Excited Heavy Mesons

We studied the hadronic decays of excited states of heavy mesons (D, D_s, B and B_s) to lighter states by emission of pi, eta or K. Wavefunctions and energy levels of these excited states are determined using a Dirac equation for the light quark in the potential generated by the heavy quark (including first order corrections in the heavy quark expansion). Transition amplitudes are computed in the context of the Heavy Chiral Quark Model.Comment: 4 pages (incl. figures), proceedings of the IV International Conference on "Hyperons, Charm and Beauty Hadrons", Valencia (Spain

First measurement of the spectral function at high energy and momentum in medium-heavy nuclei

The experiment E97-006 was performed at Jefferson Lab to measure the momentum and energy distribution of protons in the nucleus far from the region of the (approximate) validity of the mean field description, i.e. at high momentum and energies. The occurrence of this strength is long known from occupation numbers less than one. In the experiment reported here this strength was directly measured for the first time. The results are compared to modern many-body theories. Further the transparency factor of C12 was determined in the Q^2-region of 0.6 to 1.8 (GeV/c)^2.Comment: Proceeding for Fourth International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region 26.-29. Sept. 2005, Okayam

The 2p-2h electromagnetic response in the quasielastic peak and beyond

The contribution to the nuclear transverse response function R_T arising from two particle-two hole (2p-2h) states excited through the action of electromagnetic meson exchange currents (MEC) is computed in a fully relativistic framework. The MEC considered are those carried by the pion and by Delta degrees of freedom, the latter being viewed as a virtual nucleonic resonance. The calculation is performed in the relativistic Fermi gas model in which Lorentz covariance can be maintained. All 2p-2h many-body diagrams containing two pionic lines that contribute to R_T are taken into account and the relative impact of the various components of the MEC on R_T is addressed. The non-relativistic limit of the MEC contributions is also discussed and compared with the relativistic results to explore the role played by relativity in obtaining the 2p-2h nuclear response.Comment: 27 pages, 12 figures, revtex4; minor modifications in the discussion of the results, references adde

Asymmetric relativistic Fermi gas model for quasielastic lepton-nucleus scattering

We develop an asymmetric relativistic Fermi gas model for the study of the electroweak nuclear response in the quasielastic region. The model takes into account the differences between neutron and proton densities in asymmetric (N>Z) nuclei, as well as differences in the neutron and proton separation energies. We present numerical results for both neutral and charged-current processes, focusing on nuclei of interest for ongoing and future neutrino oscillation experiments. We point out some important differences with respect to the commonly employed symmetric Fermi gas model.University of Turin BARM-RILO-17Junta de Andalucía FQM160Spanish Ministerio de Economía y Competitividad and ERDF (European Regional Development Fund) FIS2014-53448-C2-1, FIS2017-88410-

Origin of Relativistic Effects in the Reaction D(e,e'p)n at GeV Energies

In a series of recent publications, a new approach to the non-relativistic reduction of the electromagnetic current operator in calculations of electro-nuclear reactions has been introduced. In one of these papers, the conjecture that at energies of a few GeV, the bulk of the relativistic effects comes from the current and not from the nuclear dynamics was made, based on the large relativistic effects in the transverse-longitudinal response. Here, we explicitly compare a fully relativistic, manifestly covariant calculation performed with the Gross equation, with a calculation that uses a non-relativistic wave function and a fully relativistic current operator. We find very good agreement up to missing momenta of 400 MeV/c, thus confirming the previous conjecture. We discuss slight deviations in cross sections for higher missing momenta and their possible origin, namely p-wave contributions and off-shell effects.Comment: 25 pages, 11 figure

Role of 2p-2h MEC excitations in superscaling

Following recent studies of inclusive electron scattering from nuclei at high energies which focused on two-nucleon emission mediated by meson-exchange currents, in this work the superscaling behavior of such contributions is investigated. Comparisons are made with existing data below the quasielastic peak where at high momentum transfers scaling of the second kind is known to be excellent and scaling of the first kind is good, in the proximity of the peak where both 1p-1h and 2p-2h contributions come into play, and above the peak where inelasticity becomes important and one finds scaling violations of the two kinds.Comment: 27 pages, 12 figures; references adde

Meson-exchange currents and quasielastic neutrino cross sections in the SuperScaling Approximation model

We evaluate the quasielastic double differential neutrino cross sections obtained in a phenomenological model based on the superscaling behavior of electron scattering data. We compare our results with the recent experimental data for neutrinos of MiniBooNE and estimate the contribution of the vector meson-exchange currents in the 2p-2h sector.Comment: 6 pages, 4 figure

Glauber theory of initial- and final-state interactions in (p,2p) scattering

We develop the Glauber theory description of initial- and final-state interactions (IFSI) in quasielastic A(p,2p) scattering. We study the IFSI-distortion effects both for the inclusive and exclusive conditions. In inclusive reaction the important new effect is an interaction between the two sets of the trajectories which enter the calculation of IFSI-distorted one-body density matrix for inclusive (p,2p) scattering and are connected with incoherent elastic rescatterings of the initial and final protons on spectator nucleons. We demonstrate that IFSI-distortions of the missing momentum distribution are large over the whole range of missing momentum both for inclusive and exclusive reactions and affect in a crucial way the interpretation of the BNL data on (p,2p) scattering. Our numerical results show that in the region of missing momentum p_{m}\lsim 100-150 MeV/c the incoherent IFSI increase nuclear transparency by 5-10\%. The incoherent IFSI become dominant at p_{m}\gsim 200 MeV/c.Comment: Accepted in Z. Phys.A, Latex, 26 pages, uuencoded 9 figure

Do final state interactions obscure short range correlation effects in quasielastic A(e,e′p)A(e,e'p) scattering?

Are short range correlations in the ground state of the target nucleus (initial state correlations ISC)observable inexperiments on quasielastic $A(e,e'p)$ scattering at large missing momentum $p_{m}$? Will the missing momentum spectrum observed at CEBAF be overwhelmed by final state interactions of the struck proton? Taking the $^{4}He$ nucleus with a realistic model wave function for a testing ground, we present a full calculation of the missing momentum distribution in inclusive $^{4}He(e,e'p)$ scattering. We find a complex interplay and strong quantum-mechanical interference of FSI and ISC contributions to scattering at large $p_{m}$, with drastic change of the interference pattern from the (anti)parallel to transverse kinematics. We show that in all the kinematical conditions, for missing momenta p_{m}\gsim 1\,fm$^{-1}$, quasielastic scattering is dominated by FSI effects and the sensitivity to details of the nuclear ground state is lost. The origin of the FSI dominance is well understood and can be traced back to the anisotropic behaviour of FSI which is long ranged in the longitudinal direction and short ranged in the transverse direction in the opposite to the short ranged ground state correlations