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We improve the model of Phys. Rev. D 76, 033005 (2007) for single pion production by neutrinos off the nucleon by partially restoring unitarity. To that end we impose Watson's theorem on the dominant vector and axial multipoles. As a result a larger CA5(0) value, in better agreement with the one obtained from the off-diagonal Goldberger-Treiman relation, is now needed in order to describe the experimental data. [ABSTRACT FROM AUTHOR]

We have studied quasielastic charged current hyperon production induced by νμ on free nucleon and the nucleons bound inside the nucleus and the results are presented for several nuclear targets like 40Ar, 56Fe and 208Pb. The hyperonnucleon transition form factors are determined from neutrino-nucleon scattering and semileptonic decays of neutron and hyperons using SU(3) symmetry. The nuclear medium effects(NME) due to Fermi motion and final state interaction(FSI) effect due to hyperon-nucleon scattering have been taken into account. Also we have studied two pion production at threshold induced by neutrinos off nucleon targets. The contribution of nucleon, pion, and contact terms are calculated using Lagrangian given by nonlinear σ model. The contribution of the Roper resonance has also been taken into account. The numerical results for the cross sections are presented and compared with the experimental results from ANL and BNL. [ABSTRACT FROM AUTHOR]

We investigate the Λ(1520) photoproduction in the γp→K+Λ (1520) reaction within the effective Lagrangian method near threshold. In addition to the "background" contributions from the contact, t-channel K exchange, and s-channel nucleon pole terms, which were already considered in previous works, the contribution from the nucleon resonance N* (2080) (spin-parity JP = 3/2-) is also considered. We show that the inclusion of the nucleon resonance N* (2080) leads to a fairly good description of the new LEPS differential cross-section data, and that these measurements can be used to determine some of the properties of this latter resonance. [ABSTRACT FROM AUTHOR]

In this work we develop a formalism to evaluate wave functions in momentum and coordinate space for the resonant states dynamically generated in a unitary coupled channel approach. The on shell approach for the scattering matrix, commonly used, is also obtained in Quantum Mechanics with a separable potential, which allows one to write wave functions in a trivial way. We develop useful relationships among the couplings of the dynamically generated resonances to the different channels and the wave functions at the origin. The formalism provides an intuitive picture of the resonances in the coupled channel approach, as bound states of one bound channel, which decays into open ones. It also provides an insight and practical rules for evaluating couplings of the resonances to external sources and how to deal with final state interaction in production processes. As an application of the formalism we evaluate the wave functions of the two Λ(1405) states in the πΣ, KN and other coupled channels. It also offers a practical way to study three body systems when two of them cluster into a resonance. [ABSTRACT FROM AUTHOR]

We analyze the effects of hyperfine mixing in b→c semileptonic and electromagnetic decays of doubly heavy baryons. [ABSTRACT FROM AUTHOR]

We follow a model based on the SU(8) symmetry for the interaction of mesons with baryons. The model treats on an equal footing the pseudo-scalars and the vector mesons, as required by heavy quark symmetry. The T-matrix calculated within an unitary scheme in coupled channels has poles which are interpreted as baryonic resonances. [ABSTRACT FROM AUTHOR]

We review the main nuclear effects that affect neutrino-nucleus cross sections. We discuss how the different models in the literature try to describe these different effects, and thus try to compare between them. We focus on the quasi-elastic reaction in the neutrino energy region of around 1 GeV, where recent data from MiniBooNE are available. Among the issues discussed are the different treatment of medium corrections to initial and final state nucleon wave functions and the problem of the rescattering of ejected nucleons. [ABSTRACT FROM AUTHOR]

We discuss different parameterizations of the C5A(q2) NΔ form factor, fitted to the old Argonne bubble chamber data for pion production by neutrinos, and we use coherent pion production to test their low q2 behavior. We find moderate effects that will be difficult to observe with the accuracy of present experiments. We also discuss the use of the Rein-Sehgal model for low energy coherent pion production. By comparison to a microscopic calculation, we show the weaknesses some of the approximations in that model that lead to very large cross sections as well as to the wrong shapes for differential ones. Finally we show that models based on the partial conservation of the axial current hypothesis are not fully reliable for differential cross sections that depend on the angle formed by the pion and the incident neutrino. [ABSTRACT FROM AUTHOR]

We present a microscopic model for neutrino induced one-pion production off the nucleon and its implementation for the purpose of calculating coherent pion production in nuclei. We further criticize the use of the Rein-Sehgal model for coherent pion production by low energy neutrinos. In particular, we show how the approximations in that model give rise to a much flatter differential cross section in the η = Eπ(1-cos θπ) variable. We discuss the limitations intrinsic to any approach based on the partial conservation of the axial current hypothesis and the inability of such models to properly determine the angular distribution of the outgoing pion with respect to the direction of the incoming neutrino. We show the effects of those limitation for the case of the dσdη differential cross section. [ABSTRACT FROM AUTHOR]

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 observables are illustrated with examples in calculations using several nuclear models and ingredients. [ABSTRACT FROM AUTHOR]

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 simplifications of the three body problem, which turns out to be easily solved by a simple variational ansatz. The wave functions obtained can be readily used to compute further observables as mass densities or form factors. The quark-quark potentials explored so far, show an overall good agreement with the experimental masses. [ABSTRACT FROM AUTHOR]

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 formalism incorporating Chiral Symmetry in the potential. Two body coupled channel unitarity is exactly preserved. The needed two particle irreducible matrix amplitude is taken from lowest order Chiral Perturbation Theory in a relativistic formalism. Off-shell behavior is parameterized in terms of low energy constants. The relation to the heavy baryon limit is discussed. The position of the complex poles in the second Riemann sheet of the scattering amplitude determine masses and widths baryonic resonances of the N(1535), N(1670), Λ(1405) and Λ(1670) resonances which compare well with accepted numbers. [ABSTRACT FROM AUTHOR]

We consider the role played by hyperfine mixing in electromagnetic and semileptonic decays of doubly heavy baryons, which give rise to large corrections to the decay widths in both cases. Our results qualitatively agree with other calculations. [ABSTRACT FROM AUTHOR]

Working in the framework of a nonrelativistic quark model we evaluate the widths for the strong one-pion decays Σc → Λc π, Σc* → Λc π and [cap_xi]c* → [cap_xi]c π. We take advantage of the constraints imposed by heavy quark symmetry to solve the three-body problem by means of a simple variational ansatz. We use partial conservation of the axial current hypothesis to get the strong vertices from weak axial current matrix elements. Our results are in good agreement with experimental data. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

We evaluate the widths for the strong decays Σc → Λc π, Σc* → Λc π and [cap_xi]c* → [cap_xi]c π. The calculations have been done within a nonrelativistic constituent quark model with wave functions that take advantage of the constraints imposed by heavy quark symmetry. Partial conservation of axial current hypothesis allows us to determine the strong vertices from an analysis of the weak axial current matrix elements. Our results are in good agreement with experimental data. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Working in the framework of a nonrelativistic quark model we evaluate the widths for the strong one-pion decays Σc → Λc π, Σc* → Λc π and [cap_xi]c* → [cap_xi]c π. We take advantage of the constraints imposed by heavy quark symmetry to solve the three-body problem by means of a simple variational ansatz. We use partial conservation of the axial current hypothesis to get the strong vertices from weak axial current matrix elements. Our results are in good agreement with experimental data. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]