Amaro, J. E., Hernández, E., Nieves, J., Valverde, M.
We have developed a model for neutrino-induced coherent pion production off nuclei in the energy regime of interest for present and forthcoming neutrino oscillation experiments. It is based on a...
Theoretical update on low energy neutrino-nucleus reactions (2008)
Nieves, J., Vicente-Vacas, M. J., Amaro, J. E., Valverde, M., Hernandez, E.
We review Quasielastic (QE) inclusive and semi--inclusive neutrino/antineutrino Charged Current (CC) and Neutral Current (NC) induced nuclear reactions at intermediate energies. We pay special...
Garcia-Recio, C., Magas, V. K., Mizutani, T., Nieves, J., Ramos, A., Salcedo, L. L.
We study charmed baryon resonances which are generated dynamically within a unitary meson-baryon coupled channel model that treats the heavy pseudoscalar and vector mesons on equal footing as...
Test of the heavy quark-light diquark approximation for baryons with a heavy quark (2008)
Hernández, E., Nieves, J., Verde-Velasco, J. M.
We check a commonly used approximation in which a baryon with a heavy quark is described as a heavy quark-light diquark system. The heavy quark influences the diquark internal motion reducing the...
Chiral SU(3) Bethe Salpeter Model: Extension to SU(6) and SU(8) Spin-Flavor Symmetries (2008)
Nieves, J., Garcia-Recio, C., Salcedo, L. L., Magas, V., Ramos, A., Mizutani, T., ...
Consistent SU(6) and SU(8) spin-flavor extensions of the SU(3) flavor Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian are constructed, which incorporate vector meson degrees of freedom. In the...
Neutrino induced weak pion production off the nucleon (2008)
Hernandez, E., Nieves, J., Valverde, M.
We study neutrino induced one-pion production off the nucleon in and around the Delta resonance region. Apart from the Delta-pole mechanism we include background terms required by chiral symmetry....
Production of Two Pions Induced by Neutrinos (2008)
Valverde, M., Nieves, J., Hernández, E., Singh, S. K., Vacas, M. J. Vicente
We study the threshold production of two pions induced by neutrinos in nucleon targets. The contribution of nucleon pole, pion and contact terms is calculated using a chiral Lagrangian. The...
Nuclear effects in neutrino induced reactions (2008)
Vacas, M. J. Vicente, Alvarez-Ruso, L., Geng, L. S., Nieves, J., Valverde, M., Hirenzaki, S.
We discuss the relevance of nuclear medium effects in the analysis of some low and medium energy neutrino reactions of current interest. In particular, we study the Quasi-Elastic (QE) process, where...
Omnes dispersion relations make a connection between form factors for exclusive semileptonic decays and phase shifts in the corresponding elastic scattering channels. We describe two applications. In...
Neutrino Interaction Calculations from MeV to GeV Region (2007)
Amaro, J. E., Nieves, J., Valverde, M., Vicente-Vacas, M. J.
The Quasi-Elastic (QE) contribution of the nuclear inclusive electron model developed in Nucl. Phys. A627 543 (1997) is extended to the study of neutrino/antineutrino Charged Current (CC) and Neutral...
Chiral Symmetry and Neutrino Pion Production off the Nucleon (2007)
Hernandez, E., Nieves, J., Valverde, M.
The neutrino pion production off the nucleon is traditionally described in the literature by means of the weak excitation of the Delta(1232) resonance and its subsequent decay into N pi. Here, we...
Neutrino induced threshold production of two pions and N^*(1440) electroweak form factors (2007)
Hernandez, E., Nieves, J., Singh, S. K., Valverde, M., Vicente-Vacas, M. J.
We study the threshold production of two pions induced by neutrinos in nucleon targets. The contribution of nucleon, pion and contact terms are calculated using a chiral Lagrangian. The contribution...
Static and dynamic properties of hadronic systems with heavy quarks b and c (2007)
Verde-Velasco, J M, Hernández, E, Nieves, J
This thesis has been devoted to the study of different properties of hadrons with one and two heavy quarks $c$ and/or $b$. All calculations have been done in the framework of a nonrelativistic...
Hernandez, E., Nieves, J., Verde-Velasco, J. M.
We show how heavy quark symmetry constraints on doubly heavy baryon semileptonic decay widths can be used to test the validity of different quark model calculations. The large discrepancies in the...
Pion Production in Neutrino-Nucleon Reactions (2007)
Hernandez, E., Nieves, J., Valverde, M.
We construct a model for the weak pion production off the nucleon, which in addition to the weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$, it includes also some...
Masses and semileptonic decays of doubly heavy baryons in a nonrelativistic quark model (2007)
Albertus, C., Hernández, E., Nieves, J., Verde-Velasco, J. M.
We evaluate masses and semileptonic decay widths for the ground state of doubly heavy $\Xi$ and $\Omega$ baryons in the framework of a nonrelativistic quark model. We solve the three-body problem by...
Weak Pion Production off the Nucleon (2007)
Hernandez, E., Nieves, J., Valverde, M.
We develop a model for the weak pion production off the nucleon, which besides the Delta pole mechanism (weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$),...
Study of the semileptonic decays B->pi, D->pi and D->K (2007)
Albertus, C., Flynn, J. M., Hernandez, E., Nieves, J., Verde-Velasco, J.M.
The semileptonic decay B->pi is studied starting from a simple quark model that takes into account the effect of the B* resonance. A novel, multiply subtracted, Omnes dispersion relation has been...
Meson-Baryon s-wave Resonances with Strangeness -3 (2006)
Garcia-Recio, C., Nieves, J., Salcedo, L. L.
Starting from a consistent SU(6) extension of the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian (Phys. Rev. D74 (2006) 034025), we study the s-wave meson-baryon resonances in the strangeness...
Quark model study of the semileptonic B -> pi decay (2006)
Albertus, C., Flynn, J. M., Hernandez, E., Nieves, J.
The semileptonic decay B->pi is studied starting from a simple quark model and taking into account the effect of the B* resonance. A novel, multiply subtracted, Omn\`es dispersion relation has been...
Large $N$ Weinberg-Tomozawa interaction and spin-flavor symmetry (2006)
Garcia-Recio, C., Nieves, J., Salcedo, L. L.
The construction of an extended version of the Weinberg-Tomozawa Lagrangian, in which baryons and mesons form spin-flavor multiplets, is reviewed and some of its properties discussed, for an...
Study of semileptonic and nonleptonic decays of the $B_c^-$ meson (2006)
Hernandez, E., Nieves, J., Verde-Velasco, J. M.
We evaluate semileptonic and two--meson nonleptonic decays of the $B_c^-$ meson in the framework of a nonrelativistic quark model. The former are done in spectator approximation using one--body...
Doubly heavy quark baryon spectroscopy and semileptonic decay (2006)
Albertus, C., Hernandez, E., Nieves, J., Verde-Velasco, J. M.
Working in the framework of a nonrelativistic quark model we evaluate the spectra and semileptonic decay widths for the ground state of doubly heavy $\Xi$ and $\Omega$ baryons. We solve the...
Resonances and the Weinberg--Tomozawa 56-baryon --35-meson interaction (2006)
Garcia-Recio, C., Nieves, J., Salcedo, L. L.
Vector meson degrees of freedom are incorporated into the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian by using a scheme which relies on spin--flavor SU(6) symmetry. The corresponding...
Study of the semileptonic decays B->pi, D->pi and D->K (2006)
Albertus, C., Flynn, J. M., Hernandez, E., Nieves, J., Verde-Velasco, J. M.
The semileptonic decay B->pi is studied starting from a simple quark model that takes into account the effect of the B* resonance. A novel, multiply subtracted, Omnes dispersion relation has been...
Strong one-pion decay of $\Sigma_c$, $\Sigma_c^*$ and $\Xi_c^*$ (2006)
Albertus, C., Hernandez, E., Nieves, J., Verde-Velasco, J. M.
Working in the framework of a nonrelativistic quark model we evaluate the widths for the strong one-pion decays $\Sigma_c\to\Lambda_c \pi$, $\Sigma_c^*\to\Lambda_c \pi$ and $\Xi_c^{*}\to\Xi_c \pi$....
Albertus, C., Hernandez, E., Nieves, J., Verde-Velasco, J. M.
We evaluate static properties and semileptonic decays for the ground state of doubly heavy $\Xi, \Xi', \Xi^*$ and $\Omega, \Omega', \Omega^*$ baryons. Working in the framework of a nonrelativistic...
Hernandez, E., Nieves, J., Valverde, M.
A potential way to distinguish tau-neutrinos from antineutrinos, below the tau-production threshold, but above the pion production one, is presented. It is based on the different behavior of the...
Hernandez, E., Nieves, J., Verde-Velasco, J. M.
We present results for different observables measured in semileptonic and non-leptonic decays of the $B_c^-$ meson. The calculations have been done within the framework of a nonrelativistic...
Nuclear effects on lepton polarization in charged-current quasielastic neutrino scattering (2006)
Valverde, M., Amaro, J. E., Nieves, J., Maieron, C.
We use a correlated local Fermi gas (LFG) model, which accounts also for long distance corrections of the RPA type and final-state interactions, to compute the polarization of the final lepton in...
Charged and Neutral Current Neutrino Induced Nucleon Emission Reactions (2006)
Nieves, J., Valverde, M., Vacas, M. J. Vicente
By means of a Monte Carlo cascade method, to account for the rescattering of the outgoing nucleon, we study the charged and neutral current inclusive one nucleon knockout reactions off nuclei induced...
Local Fermi gas in inclusive muon capture from nuclei (2006)
Amaro, J. E., Nieves, J., Valverde, M., Maieron, C.
We compare local Fermi gas and shell model in muon capture in nuclei in order to estimate the effect of finite nuclear size in low energy weak reactions.
Large Nc Weinberg-Tomozawa interaction and negative parity s--wave baryon resonances (2006)
Garcia-Recio, C., Nieves, J., Salcedo, L. L.
It is shown that in the 70 and 700 SU(6) irreducible spaces, the SU(6) extension of the Weinberg-Tomozawa (WT) s-wave meson-baryon interaction incorporating vector mesons ({\it hep-ph/0505233})...
Theoretical uncertainties on quasielastic charged-current neutrino-nucleus cross sections (2006)
Valverde, M., Amaro, J. E., Nieves, J.
We estimate the theoretical uncertainties of the model developed in Phys. Rev. C70 055503 for inclusive quasielastic charged-current neutrino-nucleus reactions at intermediate energies. Besides we...
Quasi-Elastic Neutrino-Nucleus Reactions (2006)
Valverde, M., Nieves, J., Amaro, J. E.
The quasi-elastic contribution of the nuclear inclusive electron scattering model developed in A. Gil, J. Nieves, and E. Oset: Nucl. Phys. A 627 (1997) 543; is extended to the study of electroweak...
Quark model study of the semileptonic B -> pi decay (2006)
Albertus, C., Flynn, J. M., Hernandez, E., Nieves, J., Verde-Velasco, J.M.
The semileptonic decay B->pi is studied starting from a simple quark model and taking into account the effect of the B* resonance. A novel, multiply subtracted, Omn\`es dispersion relation has been...
Strong one-pion decay of ground state charmed baryons (2005)
Albertus, C., Hernandez, E., Nieves, J., Verde-Velasco, J. M.
We evaluate the widths for the strong decays $\Sigma_c\to\Lambda_c \pi$, $\Sigma_c^*\to\Lambda_c \pi$ and $\Xi_c^{*}\to\Xi_c \pi$. The calculations have been done within a nonrelativistic constituent...
Inclusive Nucleon Emission Induced by Quasi--Elastic Neutrino--Nucleus Interactions (2005)
Nieves, J., Valverde, M., Vacas, M. J. Vicente
We study the quasi--elastic contribution to the inclusive $(\nu_l,\nu_l N)$, $(\nu_l,l^- N)$, $({\bar \nu}_l,{\bar \nu}_l N)$ and $({\bar \nu}_l,l^+ N)$ reactions in nuclei using a Monte Carlo...
Inclusive nucleon emission induced by quasi-elastic neutrino-nucleus interactions (2005)
Nieves, J., Valverde, M., Vicente-Vacas, M. J.
A previous model on inclusive charged-current quasi-elastic nuclear reactions is extended to include neutral- and charged-current nucleon emission reactions. The problem of outgoing nucleon...
Semileptonic B -> pi decays from an Omnes improved nonrelativistic constituent quark model (2005)
Albertus, C., Flynn, J. M., Hernandez, E., Nieves, J., Verde-Velasco, J.M.
The semileptonic B{yields}{pi}l{sup +}{nu}{sub l} decay is studied starting from a simple quark model which includes the influence of the B* pole. To extend the predictions of a nonrelativistic...
Albertus, C., Hernandez, E., Nieves, J., Verde-Velasco, J. M.
We present results for the strong widths corresponding to the $\Sigma_c\to \Lambda_c \pi$, $\Sigma_c^{*}\to \Lambda_c \pi$ and $\Xi_c^{*}\to \Xi_c \pi$ decays. The calculations have been done in a...
Albertus, C., Flynn, J. M., Hernández, E., Nieves, J.
The semileptonic $B\to \pi l^+ \nu_l$ decay is studied starting from a simple quark model which includes the influence of the $B^*$ pole. To extend the predictions of a nonrelativistic constituent...
SU(6) Extension of the Weinberg-Tomozawa Meson-Baryon Lagrangian (2005)
Garcia-Recio, C., Nieves, J., Salcedo, L. L.
A consistent SU(6) extension of the Weinberg-Tomozawa meson-baryon chiral Lagrangian is constructed which incorporates vector meson and baryon decuplet degrees of freedom. The corresponding...
Inclusive Quasi-Elastic Neutrino Reactions (2005)
Nieves, J., Amaro, J. E., Valverde, M., Oset, E.
The Quasi-Elastic contribution of the nuclear inclusive electron scattering model developed in Nucl. Phys. A 627 (1997) 543 is extended to the study of electroweak Charged Current induced nuclear...
Albertus, C, Hernández, E, Nieves, J, Verde-Velasco, J M
We present results for different observables in weak decays of pseudoscalar and vector mesons with a heavy $c$ or $b$ quark. The calculations are done in a nonrelativistic constituent quark model...
Albertus, C., Hernández, E., Nieves, J., Verde-Velasco, J. M.
We present results for different observables in weak decays of pseudoscalar and vector mesons with a heavy $c$ or $b$ quark. The calculations are done in a nonrelativistic constituent quark model...
Chiral dynamics of hadrons in nuclei (2005)
Oset, E., Cabrera, D., Magas, V. K., Roca, L., Vacas, M. J. Vicente, Ramos, A., ...
In this talk I report on selected topics of hadron modification in the nuclear medium using the chiral unitary approach to describe the dynamics of the problems. I shall mention how antikaons,...
A Heavy Quark Symmetry Approach to Baryons (2005)
Albertus, C., Amaro, J. E., Hernandez, E., Nieves, J.
We evaluate different properties of baryons with a heavy c or b quark. The use of Heavy Quark Symmetry (HQS) provides with an important simplification of the non relativistic three body problem which...
Albertus, C., Hernandez, E., Nieves, J.
We present the results of a nonrelativistic constituent quark model study of the semileptonic decays $\Lambda_b^0 \to \Lambda_c^+ l^- {\bar \nu}_l$ and $\Xi_b^0 \to \Xi_c^+ l^- {\bar \nu}_l$. We work...
Equivalence between local Fermi gas and shell models in inclusive muon capture from nuclei (2004)
Amaro, J. E., Maieron, C., Nieves, J., Valverde, M.
Motivated by recent studies of inclusive neutrino nucleus processes and muon capture within a correlated local Fermi gas model (LFG), we discuss the relevance of nuclear finite size effects in these...
Study of the semileptonic decay \Lambda_b^0 \to \Lambda_c^+ l^- \bar{\nu}_l (2004)
Albertus, C., Hernandez, E., Nieves, J.
Within the framework of a nonrelativistic quark model we evaluate the six form factors associated to the \Lambda_b^0 \to \Lambda_c^+ l^- \bar{\nu}_l semileptonic decay. The baryon wave functions were...
Nuclear Many-Body Theory of Electroweak Interactions with Nuclei at Intermediate Energies (2004)
Nieves, J., Amaro, J. E., Valverde, M.
The Quasi-Elastic (QE) contribution of the nuclear inclusive electron model developed in reference \cite{GNO97} is extended to the study of electroweak Charged Current (CC) induced nuclear reactions...
Inclusive Quasi-Elastic Charged-Current Neutrino-Nucleus Reactions (2004)
Nieves, J., Amaro, J. E., Valverde, M.
The Quasi-Elastic (QE) contribution of the nuclear inclusive electron scattering model developed in Nucl. Phys. A627 (1997) 543 is extended to the study of electroweak Charged Current (CC) induced...
Quark-mass dependence of baryon resonances (2004)
Lutz, M. F. M., García-Recio, C., Kolomeitsev, E. E., Nieves, J.
We study the quark-mass dependence of J^P = \frac12^- s-wave and J^P = \frac32^- d-wave baryon resonances. Parameter-free results are obtained in terms of the leading order chiral Lagrangian. In the...
Nicola, A. Gomez, Nieves, J., Pelaez, J. R., Arriola, E. Ruiz
We extend our previous analysis of the unitarized pion-nucleon scattering amplitude including up to fourth order terms in Heavy Baryon Chiral Perturbation Theory. We pay special attention to the...
Charmed and Bottom Baryons: a Variational Approach based on Heavy Quark Symmetry (2003)
Albertus, C., Amaro, J. E., Hernandez, E., Nieves, J.
The use of Heavy Quark Symmetry to study bottom and charmed baryons leads to important simplifications of the non-relativistic three body problem, which turns out to be easily solved by a simple...
Charm- and Bottom- Baryons: A Variational Approach Using Heavy Quark Symmetry (2003)
Albertus, C., Amaro, J. E., Hernandez, E., Nieves, J.
We evaluate masses of bottom and charmed baryons using several non-relativistic quark potentials which parameters have been adjusted to the meson spectra. Heavy Quark Symmetry leads to important...
Quark mass dependence of s-wave baryon resonances (2003)
Garcia-Recio, C., Lutz, M. F. M., Nieves, J.
We study the quark mass dependence of $J^P = \frac12^-$ s-wave baryon resonances. Parameter free results are obtained in terms of the leading order chiral Lagrangian. In the 'heavy' SU(3) limit with...
Chiral Symmetry and s-wave Low-Lying Meson-Baryon Resonances (2003)
Nieves, J., Garcia-Recio, C., Arriola, E. Ruiz, Vacas, M. J. Vicente
The $s-$wave meson-baryon scattering is analyzed for the isospin-strangeness $I=1/2, S=0$ and $I=0,S=-1$ sectors, in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. For both...
We use standard distorted wave theory techniques and dimensional regularization to find out solutions of the nucleon-nucleon Lippman--Schwinger equation with a kernel determined by the Weinberg's...
Meson-Baryon Interactions in Unitarized Chiral Perturbation Theory (2002)
Garcia-Recio, C., Nieves, J., Arriola, E. Ruiz, Vacas, M. Vicente
Meson-Baryon Interactions can be successfully described using both Chiral Symmetry and Unitarity. The $s-$wave meson-baryon scattering amplitude is analyzed in a Bethe-Salpeter coupled channel...
Garcia-Recio, C., Nieves, J., Arriola, E. Ruiz, Vacas, M. J. Vicente
The $s-$wave meson-baryon scattering is analyzed for the strangeness $S=-1$ and isospin I=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four channels have been...
$K^-$-Nucleus Scattering at Low and Intermediate Energies (2002)
Garcia-Recio, C., Melgarejo, A. J., Nieves, J.
We calculate $K^-$-nucleus elastic differential, reaction and total cross sections for different nuclei ($^{12}$C,$^{40}$Ca and $^{208}$Pb) at several laboratory antikaon momenta, ranging from 127...
Pionic decay of Lambda Hypernuclei in a Continuum Shell Model (2002)
Albertus, C., Amaro, J. E., Nieves, J.
We evaluate pionic decay widths of Lambda hypernuclei using a shell model for, both the nuclear bound and the continuum nucleon wave functions in the final state, and distorted waves for the outgoing...
S=--1 Meson-Baryon Scattering in Coupled Channel Unitarized Chiral Perturbation Theory (2002)
Garcia-Recio, C., Nieves, J., Arriola, E. Ruiz, Vacas, M. Vicente
The $s-$wave meson-baryon scattering amplitude is analyzed for the strangeness $S=-1$ and isospin I=0 sector in a Bethe-Salpeter coupled channel formalism incorporating Chiral Symmetry. Four two-body...
$\eta$ bound states in nuclei (2002)
Nieves, J., Inoue, T., Oset, E.
The energies and widths of bound states of the $\eta$ meson in different nuclei are obtained using the results for its selfenergy in a nuclear medium, which is evaluated in a selfconsistent manner...
Chiral restoration from pionic atoms? (2002)
Garcia-Recio, C., Nieves, J., Oset, E.
We evaluate widths and shifts of pionic atoms using a theoretical microscopical potential in which the pion decay constant $f_\pi$ is changed by an in--medium density dependent one ($f_\pi(\rho)$),...
What Does Free Space Lambda-Lambda Interaction Predict for Lambda-Lambda Hypernuclei? (2001)
Albertus, C., Amaro, J. E., Nieves, J.
Data on Lambda-Lambda hypernuclei provide a unique method to learn details on the strangeness S =-2 sector of the baryon-baryon interaction. From the free space Bonn-Julich potentials, determined...
Optical Potentials in Kaonic Atoms (2001)
Garcia-Recio, C., Nieves, J., Oset, E., Ramos, A.
A microscopic optical potential based on a chiral model is used as a starting point for studying kaonic atoms levels. We add to this potential a phenomenological part fitted to the experimentally...
Nieves, J., Valderrama, M. Pavon, Arriola, E. Ruiz
The inverse amplitude method is used to unitarize the two loop $\pi\pi$ scattering amplitudes of SU(2) Chiral Perturbation Theory in the $I=0,J=0$, $I=1,J=1$ and $I=2,J=0$ channels. An error analysis...
Chiral unitary theory: application to nuclear problems (2001)
Oset, E., Cabrera, D., Chiang, H. C., Recio, C. Garcia, Hirenzaki, S., Kamalov, S. S., ...
In this talk we briefly describe some basic elements of chiral perturbation theory, $\chi PT$, and how the implementation of unitarity and other novel elements lead to a better expansion of the $T$...
Non-localities and Fermi motion corrections in $K^-$ atoms (2000)
Garcia-Recio, C., Nieves, J., Oset, E., Ramos, A.
We evaluate the p-wave $K^-N$ amplitudes from the chiral Lagrangians and from there construct the p-wave part of the $K^-$ nucleus optical potential plus a small s-wave part induced from the...
Chiral Perturbation Theory and Unitarization (2000)
Arriola, E. Ruiz, Nicola, A. Gómez, Nieves, J., Peláez, J. R.
We review our recent work on unitarization and chiral perturbation theory both in the $\pi\pi$ and the $\pi N$ sectors. We pay particular attention to the Bethe-Salpeter and Inverse Amplitude...