J. Nieves

Neutrino-nucleus quasi-elastic and 2p2h interactions up to 10 GeV

We wish to thank Boris Popov for discussions and interpretation of details of the NOMAD analysis, and Panos Stamoulis and Kevin McFarland for discussions of how these results apply to T2K and MINERvA. This work has been produced with the support of the Spanish Ministerio de Economia y Competitividad and European FEDER funds under the Contract Nos. FIS2011-28853-C02-01, FIS2011-28853-C02-02, FPA2011-29823-C02-02, Consolider-Ingenio 2010 Programme CPAN (CSD2007-0042) and the Severo Ochoa program excellence SEV-2012-0234, the Generalitat Valenciana under Contract No. PROMETEO/2009/0090 and the E.U. HadronPhysics2 project, Grant Agreement No. 283286, and the U.S. National Science Foundation under Grants No. 0970111 and No. 1306944.

Hidden charm N and Delta resonances with heavy-quark symmetry

c and one c quarks). We analyze several possible sectors and, for the sector with zero net charm, we write down the most general Lagrangian consistent with SU(3) and heavy quark spin symmetry. We explicitly study theN andstates, which are produced from theS-wave interaction of pseudoscalar and vector mesons with 1/2 + and 3/2 + baryons within the charmless and strangeless hidden charm sector. We predict seven odd parityN-like and five �-like states with masses around 4GeV, most of them as bound states. These states form heavy-quark spin multiplets, which are almost degenerate in mass. The predicted new resonances definitely cannot be accommodated by quark models with three constituent quarks and they might be looked for in the forthcomingexperiment at the future FAIR facility.

Couplings in coupled channels versus wave functions in the case of resonances: application to the two

In this paper 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 {Lambda}(1405) states in the {pi}{Sigma}, KN, and other coupled channels. It also offers a practical way to study three-body systems when two of them cluster into a resonance.

\Lambda(1405)

Neutrinos can polarize a medium due to their weak interaction. This can manifest itself as an effective induced charge of the neutrino. We show how it is related to the Debye screening length in a plasma, first using the results of the one-loop calculation of the neutrino electromagnetic vertex and then in general to all orders in [ital e] and to leading order in the Fermi coupling. We also discuss how the results are modified if the neutrinos have mass---either Dirac- or Majorana-type.

states

We show that because of the multinucleon mechanism effects, the algorithm used to reconstruct the neutrino energy is not adequate when dealing with quasielastic-like events, and a distortion of the total flux-unfolded cross-section shape is produced. This amounts to a redistribution of strength from high to low energies, which gives rise to a sizable excess (deficit) of low (high) energy neutrinos. This distortion of the shape leads to a good description of the MiniBooNE unfolded charged current quasielastic-like cross sections published by A. A. Aguilar-Arevalo et al. [(MiniBooNE Collaboration), Phys. Rev. D 81, 092005 (2010)]. However, these changes in the shape are artifacts of the unfolding process that ignores multinucleon mechanisms.

Induced charge of neutrinos in a medium

We analyze the dependence of the squared amplitudes on the rephasing-invariant CP-violating parameters of the lepton sector, involving Majorana neutrinos, for various lepton-conserving and lepton-violating processes. We analyze the conditions under which the CP-violating effects in such processes vanish, in terms of the minimal set of rephasing invariants, giving special attention to the dependence on the extra CP-violating parameters that are due to the Majorana nature of the neutrinos.

Neutrino Energy Reconstruction and the Shape of the CCQE-like Total Cross Section

We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian within a coupled channel unitary approach in order to calculate the T-matrix for meson-baryon scattering in s-wave. The building blocks of the scheme are the pion and nucleon octets, the rho nonet and the Delta decuplet. We identify poles in this unitary T-matrix and interpret them as resonances. We study here the non exotic sectors with strangeness S=0,-1,-2,-3 and spin J=1/2, 3/2 and 5/2. Many of the poles generated can be associated with known N, Delta, Sigma, Lambda and Xi resonances with negative parity. We show that most of the low-lying three and four star odd parity baryon resonances with spin 1/2 and 3/2 can be related to multiplets of the spin-flavor symmetry group SU(6). This study allows us to predict the spin-parity of the Xi(1620), Xi(1690), Xi(1950), Xi(2250), Omega(2250) and Omega(2380) resonances, which have not been determined experimentally yet.

Rephasing-invariant CP violating parameters with Majorana neutrinos

In addition to the dielectric and magnetic permeability constants, another constant is generally needed to describe the electrodynamic properties of a linear isotropic medium. We discuss why the need for the third constant arises and what sort of physical situations can give rise to a nonzero value for it. This additional constant, which we call the ‘‘activity constant’’ and denote by ζ, can explain optical activity and other phenomena from a purely macroscopic and phenomenological point of view.

Odd-parity light baryon resonances

Abstract We have evaluated the cross section for coherent pion production in the 3 He + 12 C → t + 12 C + π + reaction. The Δ peak of the energy distribution is considerably shifted with respect to the peak in the p( 3 He ,t)Δ ++ reaction. The coherent pions represent a sizable fraction of all pions produced and are a major ingredient in the interpretation of the shift of the Δ peak in the inclusive ( 3 He,t ) reaction in nuclei. The coherent production process qualifies as production of virtual pions followed by elastic scattering of the virtual pions with the nucleus and the investigation of this channel will offer information about pion nucleus interaction complementary to the one obtained from scattering of real pions.

Third electromagnetic constant of an isotropic medium

The energies and widths of several D(0) meson bound states for different nuclei are obtained using a D-meson selfenergy in the nuclear medium, which is evaluated in a selfconsistent manner using techniques of unitarized coupled-channel theory. The kernel of the meson-baryon interaction is based on a model that treats heavy pseudoscalar and heavy vector mesons on equal footing, as required by heavy quark symmetry. We find D(0) bound states in all studied nuclei, from (12)C up to (208)Pb. The inclusion of vector mesons is the keystone for obtaining an attractive D-nucleus interaction that leads to the existence of D(0)-nucleus bound states, as compared to previous studies based on SU(4) flavor symmetry. In some cases, the half widths are smaller than the separation of the levels, what makes possible their experimental observation by means of a nuclear reaction. This can be of particular interest for the future PANDA@FAIR physics program. We also find a D(+) bound state in (12)C, but it is too broad and will have a significant overlap with the energies of the continuum