J. M. Udias

Nuclear isospin mixing and elastic parity-violating electron scattering (2009)

Moreno, Oscar, Sarriguren, Pedro, Moya De Guerra, Elvira, Udias, J.M., Donnelly, T.W., Sick, I.

27 pages, 3 tables, 9 figures.--PACS nrs.: 24.80.+y, 25.30.Bf, 21.60.Jz.-- Available on line on Jul 25, 2009.--ArXiv pre-print available at: http://arxiv.org/abs/0806.0552

Nuclear effects in electron reactions and their impact on neutrino processes (2009)

Barbaro, M. B., Amaro, J. E., Caballero, J. A., Cenni, R., Donnelly, T. W., Molinari, A., ...

We suggest that superscaling in electroweak interactions with nuclei, namely the observation that the reduced electron-nucleus cross sections are to a large degree independent of the momentum...

Neutrino Interactions Importance for Nuclear Physics (2009)

Amaro, J. E., Maieron, C., Valverde, M., Nieves, J., Barbaro, M. B., Caballero, J. A., ...

We review the general interplay between Nuclear Physics and neutrino-nucleus cross sections at intermediate and high energies. The effects of different reaction mechanisms over the neutrino...

Relativistic models for electron and neutrino-nucleus scattering (2009)

Giusti, C., Meucci, A., Pacati, F. D., Caballero, J. A., Udias, J. M.

Relativistic models developed for the exclusive and inclusive quasielastic (QE) electron scattering have been extended to charged-current (CC) and neutral-current (NC) neutrino-nucleus scattering....

Meson-exchange currents and final-state interactions in quasielastic electron scattering at high momentum transfers (2009)

Amaro, J. E., Barbaro, M. B., Caballero, J. A., Donnelly, T. W., Maieron, C., Udias, J. M.

The effects of meson-exchange currents (MEC) are computed for the one-particle one-hole transverse response function for finite nuclei at high momentum transfers $q$ in the region of the quasielastic...

Relativistic descriptions of inclusive quasielastic electron scattering: application to scaling and superscaling ideas (2009)

Meucci, Andrea, Caballero, J. A., Giusti, C., Pacati, F. D., Udias, J. M.

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...

Nuclear isospin mixing and elastic parity-violating electron scattering (2008)

Moreno, O., Sarriguren, P., De Guerra, E. Moya, Udias, J. M., Donnelly, T. W., Sick, I.

The influence of nuclear isospin mixing on parity-violating elastic electron scattering is studied for the even-even, N=Z nuclei 12C, 24Mg, 28Si, and 32S. Their ground-state wave functions have been...

Properties of Nucleon Resonances by means of a Genetic Algorithm (2008)

Fernandez-Ramirez, C., De Guerra, E. Moya, Udias, A., Udias, J. M.

We present an optimization scheme that employs a Genetic Algorithm (GA) to determine the properties of low-lying nucleon excitations within a realistic photo-pion production model based upon an...

Final-State Interactions in the Superscaling Analysis of Neutral-Current Quasielastic Neutrino Scattering (2008)

Martinez, M. C., Caballero, J. A., Donnelly, T. W., Udias, J. M.

Effects of strong final-state interactions in the superscaling properties of neutral-current quasielastic neutrino cross sections are investigated using the Relativistic Impulse Approximation as...

Spin asymmetry for the 16O(gamma,pi- p) reaction in the Delta(1232) region within an effective Lagrangian approach (2008)

Fernandez-Ramirez, C., Martinez, M. C., Vignote, J. R., Udias, J. M.

The spin asymmetry of the photon in the exclusive A(gamma,pi N)A-1 reaction is computed employing a recently developed fully relativistic model based on elementary pion production amplitudes that...

Superscaling Predictions for Neutral Current Quasielastic Neutrino-Nucleus Scattering (2008)

Martinez, M. C., Caballero, J. A., Donnelly, T. W., Udias, J. M.

The application of superscaling ideas to predict neutral-current (NC) quasielastic (QE) neutrino cross sections is investigated. Results obtained within the relativistic impulse approximation (RIA)...

Crossing symmetry and phenomenological widths in effective Lagrangian models of the pion photoproduction process (2008)

Fernandez-Ramirez, C., De Guerra, E. Moya, Udias, J. M.

We investigate the importance of crossing symmetry in effective field models and the effects of phenomenological nucleon resonance widths on the paradigmatic case of pion photoproduction. We use...

Eta Photoproduction as a Test of the Extended Chiral Symmetry (2007)

Fernandez-Ramirez, C., De Guerra, E. Moya, Udias, J. M.

We analyze the $\gamma p \to \eta p$ process from threshold up to 1.2 GeV, employing an effective Lagrangian approach that allows for a mixing of eta couplings of pseudoscalar and pseudovector...

Scaling and isospin effects in quasielastic lepton-nucleus scattering in the Relativistic Mean Field Approach (2007)

Caballero, J. A., Amaro, J. E., Barbaro, M. B., Donnelly, T. W., Udias, J. M.

The role of isospin in quasielastic electron scattering and charge-changing neutrino reactions is investigated in the relativistic impulse approximation. We analyze proton and neutron scaling...

Final-state interactions and superscaling in the semi-relativistic approach to quasielastic electron and neutrino scattering (2006)

Amaro, J. E., Barbaro, M. B., Caballero, J. A., Donnelly, T. W., Udias, J. M.

The semi-relativistic approach to electron and neutrino quasielastic scattering from nuclei is extended to include final-state interactions. Starting with the usual non-relativistic continuum shell...

Analysis of the quadrupole deformation of $\Delta$(1232) within an effective Lagrangian model for pion photoproduction from the nucleon (2006)

Fernandez-Ramirez, C., De Guerra, E. Moya, Udias, J. M.

We present an extraction of the E2/M1 ratio of the $\Delta$(1232) from experimental data applying an effective Lagrangian model. We compare the result obtained with different nucleonic models and we...

Gamow-Teller strength distributions in Xe isotopes (2006)

Moreno, O., Alvarez-Rodriguez, R., Sarriguren, P., De Guerra, E. Moya, Udias, J. M., Vignote, J. R.

The energy distributions of the Gamow-Teller strength are studied for even-even Xe isotopes with mass numbers from 124 to 142. A self-consistent microscopic formalism is used to generate the single...

Superscaling analysis of inclusive electron scattering and its extension to charge-changing neutrino-nucleus cross sections beyond the relativistic Fermi gas approach (2006)

Antonov, A. N., Ivanov, M. V., Gaidarov, M. K., De Guerra, E. Moya, Caballero, J. A., Barbaro, M. B., ...

Superscaling analyses of inclusive electron scattering from nuclei are extended from the quasielastic processes to the delta excitation region. The calculations of $(e,e^\prime)$ cross sections for...

FIRST: Fast Iterative Reconstruction Software for (PET) tomography (2006)

Herraiz, J. L., Espana, S., Vaquero, J. J., Desco, M., Udias, J. M.

Small animal PET scanners require high spatial resolution and good sensitivity. To reconstruct high-resolution images in 3D-PET, iterative methods, such as OSEM, are superior to analytical...

Erratum: Scaling functions and superscaling in medium and heavy nuclei (2006)

Antonov, A. N., Ivanov, M. V., Gaidarov, M. K., Moya De Guerra, Elvira, Sarriguren, Pedro, Udias, J. M.

1 page.-- PACS nrs.: 25.30.Fj; 21.10.Ft; 21.60.-n; 99.10.Cd.-- Original article published in Physical Review C 73(4): 047302(2006), available at: http://hdl.handle.net/10261/15039

Scaling functions and superscaling in medium and heavy nuclei (2006)

Antonov, A. N., Ivanov, M. V., Gaidarov, M. K., Moya De Guerra, Elvira, Sarriguren, Pedro, Udias, J. M.

4 pages, 1 figure.-- PACS nrs.: 25.30.Fj; 21.60.-n; 21.10.Ft; 21.10.Gv.-- ArXiv pre-print available at: http://arxiv.org/abs/nucl-th/0603048v1

Scaling Functions and Superscaling in Medium and Heavy Nuclei (2006)

Antonov, A. N., Ivanov, M. V., Gaidarov, M. K., De Guerra, E. Moya, Sarriguren, P., Udias, J. M.

The scaling function $f(\psi')$ for medium and heavy nuclei with $Z\neq N$ for which the proton and neutron densities are not similar is constructed within the coherent density fluctuation model...

Hints on the quadrupole deformation of the $\Delta$(1232) (2006)

Fernandez-Ramirez, C., De Guerra, E. Moya, Udias, J. M.

The E2/M1 ratio (EMR) of the $\Delta$(1232) is extracted from the world data in pion photoproduction by means of an Effective Lagrangian Approach (ELA).This quantity has been derived within a...

Charge and matter distributions and form factors of light, medium, and heavy neutron-rich nuclei (2005)

Antonov, A.N., Kadrev, D.N., Gaidarov, M.K., Moya De Guerra, Elvira, Sarriguren, Pedro, Udias, J. M., ...

11 pages, 3 tables, 11 figures.--PACS nrs.: 21.10.Ft; 21.10.Gv; 25.30.Bf; 21.60.−n.--ArXiv pre-print available at: http://arxiv.org/abs/nucl-th/0506056v2

Effective Lagrangian Approach to pion photoproduction from the nucleon (2005)

Fernandez-Ramirez, C., De Guerra, E. Moya, Udias, J. M.

We present a pion photoproduction model on the free nucleon based on an Effective Lagrangian Approach (ELA) which includes the nucleon resonances ($\Delta(1232)$, N(1440), N(1520), N(1535), $\Delta...

Charge and matter distributions and form factors of light, medium and heavy neutron-rich nuclei (2005)

Antonov, A. N., Kadrev, D. N., Gaidarov, M. K., De Guerra, E. Moya, Sarriguren, P., Udias, J. M., ...

Results of charge form factors calculations for several unstable neutron-rich isotopes of light, medium and heavy nuclei (He, Li, Ni, Kr, Sn) are presented and compared to those of stable isotopes in...

Relativistic models for quasi-elastic neutrino scattering (2005)

Martinez, M. C., Lava, P., Jachowicz, N., Ryckebusch, J., Vantournhout, K., Udias, J. M.

We present quasi-elastic neutrino-nucleus cross sections in the energy range from 150 MeV up to 5 GeV for the target nuclei 12C and 56Fe. A relativistic description of the nuclear dynamics and the...

Superscaling in charged current neutrino quasielastic scattering in the relativistic impulse approximation (2005)

Caballero, J. A., Amaro, J. E., Barbaro, M. B., Donnelly, T. W., Maieron, C., Udias, J. M.

Superscaling of the quasielastic cross section in charged current neutrino-nucleus reactions at energies of a few GeV is investigated within the framework of the relativistic impulse approximation....

Superscaling, scaling functions, and nucleon momentum distributions in nuclei (2005)

Antonov, A.N., Gaidarov, M.K., Ivanov, M.V., Kadrev, D.N., Moya De Guerra, Elvira, Sarriguren, Pedro, ...

11 pages, 4 figures.--PACS nrs.: 25.30.Fj; 21.60.-n; 21.10.Ft; 24.10.Jv.--ArXiv pre-print available at: http://arxiv.org/abs/nucl-th/0411100v1

Superscaling, Scaling Functions and Nucleon Momentum Distributions in Nuclei (2004)

Antonov, A. N., Gaidarov, M. K., Ivanov, M. V., Kadrev, D. N., De Guerra, E. Moya, Sarriguren, P., ...

The scaling functions $f(\psi')$ and $F(y)$ from the $\psi'$- and $y$-scaling analyses of inclusive electron scattering from nuclei are explored within the coherent density fluctuation model (CDFM)....

A( e→ , e' p→ )B responses: From bare nucleons to complex nuclei (2004)

Vignote, Javier R., Martínez, M.C., Caballero, J.A., Moya De Guerra, Elvira, Udias, J.M.

12 pages, 1 table, 5 figures, 2 appendices.--PACS nrs.: 25.30.Rw; 24.10.Jv; 21.60.Cs.--ArXiv pre-print available at: http://arxiv.org/abs/nucl-th/0312076v2

Measurement of Rlt and Atl in the 4He(e,e'p)3H Reaction at pmiss of 130-300 MeV/c (2004)

Aniol, K. A., Epstein, M. B., Gama, E., Margaziotis, D. J., Bertozzi, W., Chen, J. P., ...

We have measured the 4He(e,e'p)3H reaction at missing momenta of 130-300 MeV/c using the three-spectrometer facility at the Mainz microtron MAMI. Data were taken in perpendicular kinematics to allow...

Final state interaction effects in neutrino-nucleus quasielastic scattering (2004)

Maieron, C., Martinez, M. C., Caballero, J. A., Udias, J. M.

We consider the charged-current quasielastic scattering of muon neutrinos on an Oxygen 16 target, described within a relativistic shell model and, for comparison, the relativistic Fermi gas. Final...

Superscaling in Nuclei: A Search for Scaling Function Beyond the Relativistic Fermi Gas Model (2004)

Antonov, A. N., Gaidarov, M. K., Kadrev, D. N., Ivanov, M. V., De Guerra, E. Moya, Udias, J. M.

We construct a scaling function $f(\psi^{\prime})$ for inclusive electron scattering from nuclei within the Coherent Density Fluctuation Model (CDFM). The latter is a natural extension to finite...

Nuclear transparencies in relativistic A(e,e'p) models (2004)

Lava, P., Martinez, M. C., Ryckebusch, J., Caballero, J. A., Udias, J. M.

Relativistic and unfactorized calculations for the nuclear transparency extracted from exclusive A(e,e'p) reactions for 0.3 \leq Q^2 \leq 10 (GeV/c)^2 are presented for the target nuclei C, Si, Fe...

A$(\vec{e},e'\vec{p})$B responses: from bare nucleons to complex nuclei (2003)

Vignote, Javier R., Martinez, M. C., Caballero, J. A., De Guerra, E. Moya, Udias, J. M.

We study the occurrence of factorization in polarized and unpolarized observables in coincidence quasi-elastic electron scattering. Starting with the relativistic distorted wave impulse...

Polarization transfer in the 4He(e over-right-arrow,e 'p over-right-arrow)3H reaction up to Q2=2.6 (GeV/c)2 (2003)

Strauch, S., Dieterich, S., Aniol, K.A., Annand, J.R.M., Baker, O.K., Bertozzi, W., ...

We have measured the proton recoil polarization in the He-4((e) over right arrow ,e(')(p) over right arrow)H-4 reaction at Q(2)=0.5, 1.0, 1.6, and 2.6 (GeV/c)(2). The measured ratio of polarization...

Recent Developments in relativistic models for exclusive (e,e'p) reactions (2001)

Udias, J. M., Vignote, Javier R., De Guerra, E. Moya, Escuderos, A., Caballero, J. A.

A comparison of impulse approximation calculations for the (e,e'p) reaction, based on the Dirac equation and the Schrodinger one is presented. Trivial (kinematics) differences are indicated, as well...

Polarization transfer in the 4He(e,e'p)3H reaction (2001)

Dieterich, S., Bartsch, P., Baumann, D., Bermuth, J., Bohinc, K., Bohm, R., ...

Polarization transfer in the4He(e,e'p)3H reaction at a Q2 of 0.4 (GeV/c)2 was measured at the Mainz Microtron MAMI. The ratio of the transverse to the longitudinal polarization components of the...

Relativistic mean field approximation to the analysis of 16O(e,e'p)15N data at |Q^2|\leq 0.4 (GeV/c)^2 (2001)

Udias, J. M., Caballero, J. A., De Guerra, E. Moya, Vignote, Javier R., Escuderos, A.

We use the relativistic distorted wave impulse approximation to analyze data on 16O(e,e'p)15N at |Q^2|\leq 0.4 (GeV/c)^2 that were obtained by different groups and seemed controversial. Results for...

Polarization transfer in the $^{4}$He$(\vec{e},e' \vec{p}^{3}$H reaction (2000)

Dieterich, S., Bartsch, P., Baumann, D., Bermuth, J., Bohinc, K., Böhm, R., ...

Polarization transfer in the 4He(e,e'p)3H reaction at a Q^2 of 0.4 (GeV/c)^2 was measured at the Mainz Microtron MAMI. The ratio of the transverse to the longitudinal polarization components of the...

Relativistic nuclear structure effects in (e,e' vec{p}) (2000)

Udias, J. M., Vignote, Javier R.

Results for recoil nucleon induced polarization for $(e,e'\vec{p})$ are presented using various approximations for the relativistic nucleonic current, at the kinematics of a recent experiment at...

Quaiselastic scattering from relativistic bound nucleons: Transverse-Longitudinal response (1999)

Udias, J. M., Caballero, J. A., De Guerra, E. Moya, Amaro, J. E., Donnelly, T. W.

Predictions for electron induced proton knockout from the $p_{1/2}$ and $p_{3/2}$ shells in $^{16}$O are presented using various approximations for the relativistic nucleonic current. Results for the...

Strange form factors of the proton: a new analysis of the neutrino (antineutrino) data of the BNL-734 experiment (1998)

Alberico, W. M., Barbaro, M. B., Bilenky, S. M., Caballero, J. A., Giunti, C., Maieron, C., ...

We consider ratios of elastic neutrino(antineutrino)-proton cross sections measured by the Brookhaven BNL-734 experiment and use them to obtain the neutral current (NC) over charged current (CC)...

Relativistic current densities for bound spin-orbit partners and the longitudinal-transverse response in (e,e'p) processes (1998)

Caballero, J. A., Donnelly, T. W., De Guerra, E. Moya, Udias, J. M.

Scalar, baryon and vector--current densities in coordinate and momentum space are calculated within a relativistic mean--field model. The role of the low components of the bound nucleon wave function...

The ratio of p and n yields in NC neutrino(antineutrino)-nucleus scattering and strange form factors of the nucleon (1997)

Alberico, W. M., Barbaro, M. B., Bilenky, S. M., Caballero, J. A., Giunti, C., Maieron, C., ...

We calculate the ratio of proton and neutron yields in NC induced neutrino(antineutrino)-nucleus inelastic scattering at neutrino energies of about 1 GeV. We show that this ratio depends very weakly...

Analysis of factorization in (e,e'p) reactions: A survey of the relativistic plane wave impulse approximation (1997)

Caballero, J. A., Donnelly, T. W., De Guerra, E. Moya, Udias, J. M.

The issue of factorization within the context of coincidence quasi-elastic electron scattering is reviewed. Using a relativistic formalism for the entire reaction mechanism and restricting ourselves...

Correlations and the Cross Section of Exclusive ($e,e'p$) Reactions for $^{16}$O (1997)

Udias, J. M., Müther, H., Skouras, L. D., Polls, A.

The reduced cross section for exclusive ($e,e'p$) reactions has been studied in DWIA for the example of the nucleus $^{16}$O using a spectral function containing effects of correlations. The spectral...

Inelastic neutrino and antineutrino scattering on nuclei and ``strangeness'' of the nucleon (1997)

Alberico, W. M., Barbaro, M. B., Bilenky, S. M., Caballero, J. A., Giunti, C., Maieron, C., ...

Possibilities to extract information on the strange form factors of the nucleon from neutrino (antineutrino) inelastic scattering on nuclei, in an energy range from 200 MeV to 1 GeV and more, are...

Relativistic analysis of the 208Pb(e,e'p)207Tl reaction at high momentum (1996)

Udias, J. M., Sarriguren, P., De Guerra, E. Moya, Caballero, J. A.

The recent 208Pb(e,e'p)207Tl data from NIKHEF-K at high missing momentum (p_m>300 MeV/c) are compared to theoretical results obtained with a fully relativistic formalism previously applied to analyze...

Exchange Current Corrections to Neutrino-Nucleus Scattering. I. Nuclear Matter (1996)

Umino, Y., Udias, J. M.

Relativistic exchange current corrections to the impulse approximation in low and intermediate energy neutrino--nucleus scattering are presented assuming non--vanishing strange quark form factors for...

Parity violation in quasielastic electron scattering from closed-shell nuclei (1995)

Amaro, J. E., Caballero, J. A., Donnelly, T. W., Lallena, A. M., De Guerra, E. Moya, Udias, J. M.

The electromagnetic and weak neutral current matrix elements that enter in the analysis of parity-violating quasielastic electron scattering are calculated using a continuum nuclear shell model. New...

Exchange Current Corrections to Neutrino--Nucleus Scattering (1995)

Umino, Y., Udias, J. M., Mulders, P. J.

Relativistic exchange current corrections to neutrino--nucleus cross sections are presented assuming non--vanishing strange quark form factors for the constituent nucleons. For charged current...

Probing Deformed Orbitals with \vec{A}(\vec{e}, e' N)B reactions (1994)

Garrido, E., Caballero, J. A., De Guerra, E. Moya, Sarriguren, P., Udias, J. M.

We present results for response functions and asymmetries in the nuclear reactions 37\vec{Ar}(\vec{e},e'n)36Ar and 37\vec{K}(\vec{e},e' p)36Ar at quasifree kinematics. We compare PWIA results...

Spin dependent Momentum Distributions in Deformed Nuclei (1994)

Caballero, J. A., Garrido, E., De Guerra, E. Moya, Sarriguren, P., Udias, J. M.

We study the properties of the spin dependent one body density in momentum space for odd--A polarized deformed nuclei within the mean field approximation. We derive analytic expressions connecting...

Exchange current corrections to neutrino-nucleus scattering (1994)

Umino, Y, Udias, J M, Mulders, P J

Relativistic exchange current corrections to neutrino--nucleus cross sections are presented assuming non--vanishing strange quark form factors for the constituent nucleons. For charged current...

Relativistic versus Nonrelativistic Optical Potentials in A(e,e'p)B Reactions (1993)

Udias, J. M., Sarriguren, P., De Guerra, E. Moya, Garrido, E., Caballero, J. A.

We investigate the role of relativistic and nonrelativistic optical potentials used in the analysis of ($e,e'p$) data. We find that the relativistic calculations produce smaller ($e,e'p$) cross...

Spectroscopic Factors in $^{40}$Ca and $^{208}$Pb from $(e,e'p)$: Fully Relativistic Analysis (1993)

Udias, J. M., Sarriguren, P., De Guerra, E. Moya, Garrido, E., Caballero, J. A.

We present results for spectroscopic factors of the outermost shells in $^{40}$Ca and $^{208}$Pb, which have been derived from the comparison between the available quasielastic ($e,e'p$) data from...

Polarization transfer in the 4He(e,e'p)3H reaction

Dieterich, S., Bartsch, P., Baumann, D., Bermuth, J., Bohinc, K., Bohm, R., ...

Polarization transfer in the4He(e,e'p)3H reaction at a Q2 of 0.4 (GeV/c)2 was measured at the Mainz Microtron MAMI. The ratio of the transverse to the longitudinal polarization components of the...

Polarization transfer in the 4He(e over-right-arrow,e 'p over-right-arrow)3H reaction up to Q2=2.6 (GeV/c)2

Strauch, S., Dieterich, S., Aniol, K.A., Annand, J.R.M., Baker, O.K., Bertozzi, W., ...

We have measured the proton recoil polarization in the He-4((e) over right arrow ,e(')(p) over right arrow)H-4 reaction at Q(2)=0.5, 1.0, 1.6, and 2.6 (GeV/c)(2). The measured ratio of polarization...

Polarization transfer in the 4He(e,e'p)3H reaction

Dieterich, S., Bartsch, P., Baumann, D., Bermuth, J., Bohinc, K., Bohm, R., ...

Polarization transfer in the4He(e,e'p)3H reaction at a Q2 of 0.4 (GeV/c)2 was measured at the Mainz Microtron MAMI. The ratio of the transverse to the longitudinal polarization components of the...

Polarization transfer in the 4He(e over-right-arrow,e 'p over-right-arrow)3H reaction up to Q2=2.6 (GeV/c)2

Strauch, S., Dieterich, S., Aniol, K.A., Annand, J.R.M., Baker, O.K., Bertozzi, W., ...

We have measured the proton recoil polarization in the He-4((e) over right arrow ,e(')(p) over right arrow)H-4 reaction at Q(2)=0.5, 1.0, 1.6, and 2.6 (GeV/c)(2). The measured ratio of polarization...