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Sajjad Athar, M., Ruiz Simo, I., & Vicente Vacas, M. J. (2011). Nuclear medium modification of the F2(x, Q^2) structure function. Nucl. Phys. A, 857(1), 29–41.
Abstract: We study the nuclear effects in the electromagnetic structure function F-2(x, Q(2)) in the deep inelastic lepton nucleus scattering process by taking into account Fermi motion, binding, pion and rho meson cloud contributions. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations. The ratios R-F2(A) (x, Q(2)) = 2F(2)(A)(x, Q(2))/AF(2)(D)(x, Q(2)) are obtained and compared with recent JLab results for light nuclei with special attention to the slope of the x distributions. This magnitude shows a non-trivial A dependence and it is insensitive to possible normalization uncertainties. The results have also been compared with some of the older experiments using intermediate mass nuclei.
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Nieves, J., Ruiz Simo, I., & Vicente Vacas, M. J. (2011). Inclusive charged-current neutrino-nucleus reactions. Phys. Rev. C, 83(4), 045501–19pp.
Abstract: We present a model for weak charged-current induced nuclear reactions at energies of interest for current and future neutrino oscillation experiments. This model is a natural extension of the work in Refs. [1,2], where the quasielastic contribution to the inclusive electron and neutrino scattering on nuclei was analyzed. The model is based on a systematic many-body expansion of the gauge boson absorption modes that includes one, two, and even three-body mechanisms, as well as the excitation of Delta isobars. The whole scheme has no free parameters, besides those previously adjusted to the weak pion production off the nucleon cross sections in the deuteron, since all nuclear effects were set up in previous studies of photon, electron, and pion interactions with nuclei. We have discussed at length the recent charged-current quasielastic MiniBooNE cross section data, and showed that two-nucleon knockout mechanisms are essential to describing these measurements.
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Haider, H., Ruiz Simo, I., Sajjad Athar, M., & Vicente Vacas, M. J. (2011). Nuclear medium effects in nu(nu)-nucleus deep inelastic scattering. Phys. Rev. C, 84(5), 054610–13pp.
Abstract: We study nuclear medium effects in the weak structure functions F(2)(x, Q(2)) and F(3)(x, Q(2)) in the deep inelastic neutrino and antineutrino induced reactions in nuclei. We use a theoretical model for the nuclear spectral functions which incorporates the conventional nuclear effects, such as Fermi motion, binding, and nucleon correlations. We also consider the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. The calculations have been performed using relativistic nuclear spectral functions. Our results are compared with the experimental data of the NuTeV and the CERN Dortmund Heidelberg Saclay Warsaw (CDHSW) collaborations.
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Haider, H., Ruiz Simo, I., & Sajjad Athar, M. (2012). nu((nu)over-bar)-Pb-208 deep-inelastic scattering. Phys. Rev. C, 85(5), 055201–11pp.
Abstract: Nuclear-medium effects on the weak structure functions F-2(x, Q(2)) and F-3(x, Q(2)) in charged-current neutrino and antineutrino induced deep-inelastic reactions in Pb-208 have been studied. The calculations have been performed in a theoretical model using relativistic nuclear spectral functions which incorporate Fermi motion, binding, and nucleon correlations. We have also included the pion and rho meson cloud contributions calculated from a microscopic model for meson-nucleus self-energies. Using these structure functions, differential scattering cross sections have been obtained and compared with the CERN Hybrid Oscillation Research Apparatus (CHORUS) data. The results for the ratios 2F(i)(Pb)/208F(i)(D), 4F(i)(Pb)/208F(i)(He), 12F(i)(Pb)/208F(i)(C), 16F(i)(Pb)/208F(i)(O), and 56F(i)(Pb)/208F(i)(Fe) (i = 2, 3) have also been obtained and compared with some of the phenomenological fits.
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Alvarez-Ruso, L., Nieves, J., Ruiz Simo, I., Valverde, M., & Vicente Vacas, M. J. (2013). Charged kaon production by coherent scattering of neutrinos and antineutrinos on nuclei. Phys. Rev. C, 87(1), 015503–11pp.
Abstract: With the aim of achieving a better and more complete understanding of neutrino interactions with nuclear targets, the coherent production of charged kaons induced by neutrinos and antineutrinos is investigated in the energy range of some of the current neutrino experiments. We follow a microscopic approach which, at the nucleon level, incorporates the most important mechanisms allowed by the chiral-symmetry-breaking pattern of QCD. The distortion of the outgoing K ((K) over bar) is taken into account by solving the Klein-Gordon equation with realistic optical potentials. Angular and momentum distributions, as well as the energy and nuclear dependence of the total cross section, are studied.
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Rafi Alam, M., Ruiz Simo, I., Sajjad Athar, M., & Vicente Vacas, M. J. (2010). Weak kaon production off the nucleon. Phys. Rev. D, 82(3), 033001–8pp.
Abstract: The weak kaon production off the nucleon induced by neutrinos is studied at the low and intermediate energies of interest for some ongoing and future neutrino oscillation experiments. This process is also potentially important for the analysis of proton decay experiments. We develop a microscopical model based on the SU(3) chiral Lagrangians. The basic parameters of the model are f pi, the pion decay constant, Cabibbo's angle, the proton and neutron magnetic moments, and the axial vector coupling constants for the baryons octet, D and F, that are obtained from the analysis of the semileptonic decays of neutron and hyperons. The studied mechanisms are the main source of kaon production for neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross sections are large enough to be amenable to be measured by experiments such as Minerva and T2K.
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Rafi Alam, M., Ruiz Simo, I., Sajjad Athar, M., & Vicente Vacas, M. J. (2012). Antineutrino induced antikaon production off the nucleon. Phys. Rev. D, 85(1), 013014–8pp.
Abstract: The charged-current antikaon production off nucleons induced by antineutrinos is studied at low and intermediate energies. We extend here our previous calculation on kaon production induced by neutrinos. We have developed a microscopic model that starts from the SU(3) chiral Lagrangians and includes background terms and the resonant mechanisms associated to the lowest lying resonance in the channel, namely, the Sigma*(1385). Our results could be of interest for the background estimation of various neutrino oscillation experiments like MiniBooNE and SuperK. They can also be helpful for the planned (nu) over bar experiments like MINER nu A, NO nu A, and T2K phase II, and for beta-beam experiments with antineutrino energies around 1 GeV.
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Nieves, J., Sanchez, F., Ruiz Simo, I., & Vicente Vacas, M. J. (2012). Neutrino energy reconstruction and the shape of the charged current quasielastic-like total cross section. Phys. Rev. D, 85(11), 113008–9pp.
Abstract: 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.
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Rafi Alam, M., Ruiz Simo, I., Sajjad Athar, M., & Vicente Vacas, M. J. (2013). Charged lepton induced one kaon production off the nucleon. Phys. Rev. D, 87(5), 053008–7pp.
Abstract: We study single kaon production off the nucleon induced by electrons (positrons) i.e., e(-) (e(+)) + N -> v(e) ((v) over bar (e)) + (K) over bar (K) + N' at low energies. The possibility of observing these processes with the high luminosity beams available at TJNAF and Mainz is discussed, taking into account that the strangeness conserving electromagnetic reactions have a higher energy threshold for (K) over bar (K) production. The calculations are done using a microscopic model that starts from the SU(3) chiral Lagrangians and includes background terms and the resonant mechanisms associated to the lowest lying resonance Sigma*(1385)
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Rafi Alam, M., & Ruiz Simo, I. (2019). Weak production of strange Xi baryons off the nucleon. Phys. Rev. D, 100(3), 033001–10pp.
Abstract: The charged current Cabibbo-suppressed associated K Xi production off the nucleon induced by antineutrinos is studied at low and intermediate energies. The nonresonant terms are obtained using a microscopical model based on the SU( 3) chiral Lagrangian. The basic parameters of the model are f(pi), the pion decay constant, Cabibbo's angle, the proton and neutron magnetic moments, and the axial vector coupling constants for the baryons octet, D and F, that are obtained from the analysis of the semileptonic decays of neutron and hyperons. In addition, we also consider Sigma(*)(1385) resonance, which can decay in K Xi final state when this channel is open. The studied mechanism is the prime source of Xi production at antineutrino energies around 2 GeV and the calculated cross sections at these energies can be measured at the current and future neutrino experiments.
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