We present results of an updated calculation of the 2p2h (two particle two hole) contribution to the neutrino-induced charge-current cross section. We provide also some exclusive observables, interesting from the point of view of experimental studies, e.g. distributions of momenta of the outgoing nucleons and of available energy, which we compare with the results obtained within the NEUT generator. We also compute, and separate from the total, the contributions of 3p3h mechanisms. Finally, we discuss the differences between the present results and previous implementations of the model in MC event-generators, done at the level of inclusive cross sections, which might significantly influence the experimental analyses, particularly in the cases where the hadronic observables are considered.
Whereas a nonrelativistic distorted wave model fails to quantitatively describe analyzing power data for exclusive proton-induced proton-knockout from the 3s_{1/2} state in Pb-208 at 202 MeV, the corresponding relativistic prediction provides a perfect description, thus suggesting that the Dirac equation is the more appropriate underlying dynamical equation. We check the consistency of this rsult by comparing predictions for both dynamical models to new high resolution data for 3s_{1/2} knockout in Pb-208 at a higher incident energy of 392 MeV.
Within the framework of the relativistic distorted wave impulse approximation (DWIA), we investigate the sensitivity of complete sets of polarization transfer observables for exclusive proton knockout from the 3s$_{1/2}$, 2d$_{3/2}$ and 2d$_{5/2}$ states in $^{208}$Pb, at an incident laboratory kinetic energy of 202 MeV, and for coincident coplanar scattering angles ($28.0^{\circ}$, $-54.6^{\circ}$), to different distorting optical potentials, finite-range (FR) versus zero-range (ZR) approximations to the DWIA, as well as medium-modified meson-nucleon coupling constants and meson masses. Resul…
The triple differential cross section (TDX) for the 12C(p,2p) proton knockout reaction from the 1p3/2 single-particle state measured at 392 MeV is investigated by nonrelativistic distorted wave impulse approximation (DWIA) with accurate treatment of the kinematics of the colliding two protons and effects of in-medium modification to the matrix elements of the proton-proton (pp) effective interaction. Some simplifying approximations made in previous studies with DWIA are examined. The off-the-energy-shell matrix elements of the pp effective interaction are shown to play an essential role in des…
Within the framework of the relativistic plane wave impulse approximation, we study the observable consequences of employing a complete Lorentz invariant representation of the NN scattering matrix in terms of 44 independent amplitudes, as opposed to the previously-employed, but ambiguous, five-term Lorentz invariant parametrization of the NN scattering matrix, for the prediction of complete sets of exclusive ($\vec{p},2 \vec{p} $) polarization transfer observables. Two kinematic conditions are considered, namely proton knockout from the $3s_{1/2}$ state of $^{208}$Pb at an incident energy of 2…
Cross sections and photon asymmetries of the exclusive 16O(γ,pn)14N and 16O(γ,pp)14C knockout reactions are calculated for transitions to the low-lying discrete final states of the residual nucleus in the photon-energy range between 100 and 400 MeV. Exclusive reactions may represent a test of reaction mechanisms and a promising tool for investigating the dynamics of nucleon pairs in different states. Cross sections and asymmetries for both (γ,pn) and (γ,pp) turn out to be only slightly affected by short-range correlations and dominated by two-body currents. Therefore, two-nucleon knockout reac…
We investigate the factorization properties of the exclusive electroinduced two-nucleon knockout reaction $A(e,e'pN)$. A factorized expression for the cross section is derived and the conditions for factorization are studied. The $A(e,e'pN)$ cross section is shown to be proportional to the conditional center-of-mass (c.m.) momentum distribution for close-proximity pairs in a state with zero relative orbital momentum and zero radial quantum number. The width of this conditional c.m. momentum distribution is larger than the one corresponding with the full c.m. momentum distribution. It is shown …
Background: Nuclear short-range correlations (SRCs) are corrections to mean-field wave functions connected with the short-distance behavior of the nucleon-nucleon interaction. These SRCs provide corrections to lepton- nucleus cross sections as computed in the impulse approximation (IA). Purpose: We want to investigate the influence of SRCs on the one-nucleon (1N) and two-nucleon (2N) knockout channel for muon-neutrino induced processes on a $^{12}$C target at energies relevant for contemporary measurements. Method: The model adopted in this work, corrects the impulse approximation for SRCs by …
The attempts to investigate correlations in electromagnetically induced one- and two-nucleon knockout are reviewed. The theoretical framework for cross section calculations is outlined and some results are presented for the exclusive $^{16}$O($e,e'p)^{15}$N and $^{16}$O($e,e'pp)^{14}$C reactions. For the ($e,e'p$) reaction attention is focussed on extracting the spectroscopic factors. For the ($e,e'pp$) reaction the possibility of obtaining direct and clear information on short-range correlations is discussed.
We consider high-energy quasifree single- and two-proton knockout reactions induced by electrons and protons and address the question what target-nucleus densities can be effectively probed after correcting for nuclear attenuation (initial- and final-state interactions). Our calculations refer to ejected proton kinetic energies of 1.5 GeV, the reactions (e,e'p), (γ,pp) and (p,2p) and a carbon target. It is shown that each of the three reactions is characterized by a distinctive sensitivity to the density of the target nucleus. The bulk of the (γ,pp) strength stems from the high-density regions…
We present a model to calculate cross sections for electroinduced two-nucleon emission from finite nuclei. Short-range correlations in the wave functions and meson-exchange contributions to the photoabsorption process are implemented. Effects of the short-range correlations are studied with the aid of a perturbation expansion method with various choices of the Jastrow correlation function. The model is used to investigate the relative importance of the different reaction mechanisms contributing to the A(e,e$'$pn) and A(e,e$'$pp) process. Representative examples for the target nuclei $^{12}$C a…
We have extended our model for charged current neutrino-nucleus interactions to neutral current reactions. For the elementary neutrino-nucleon interaction, we take into account quasielastic scattering, Delta excitation and the excitation of the resonances in the second resonance region. Our model for the neutrino-nucleus collisions includes in-medium effects such as Fermi motion, Pauli blocking, nuclear binding, and final-state interactions. They are implemented by means of the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) coupled-channel transport model. This allows us to study exclusive channe…
The nonlinear model of pionic condensate in nuclei by G. Preparata can be efficiently verified by investigation of the quasielastic knockout process of pions out of nuclei by high energy electrons. First, a momentum distribution (MD) of the collective pions has a bright maximum at q=0.3 Gev.Second the excitation spectrum of a recoil nucleus is concentrated at low energies E lesser than 1MeV. The results for the pion knockout from mesonic clouds of individual nucleons are absolutely different. The latter results are presented both for pion and rho-meson clouds localized on nucleons.
The treatment of the $Δ$-current and its contribution in the exclusive $^{16}$O$(e,e'pp)^{14}$C and $^{16}$O$(γ,pp)^{14}$C knockout reactions are investigated in combination with the effects of correlations. Different parametrizations of the effective $Δ$-current and different treatments of correlations in the two-nucleon overlap function are considered. The results are presented and discussed for a suitable choice of kinematics. It is found that the investigation of different mutually supplementing kinematics is necessary to resolve the uncertainties in the theoretical ingredients and extract…
[Background] The neutrino-nucleus ($νA$) cross section is a major source of systematic uncertainty in neutrino-oscillation studies. A precise $νA$ scattering model, in which multinucleon effects are incorporated, is pivotal for an accurate interpretation of the data. [Purpose] In $νA$ interactions, meson-exchange currents (MECs) can induce two-nucleon ($2N$) knockout from the target nucleus, resulting in a two-particle two-hole (2p2h) final state. They also affect single nucleon ($1N$) knockout reactions, yielding a one-particle one-hole (1p1h) final state. Both channels affect the inclusive s…
Developed earlier concept of quasielastic knock out of pions from nucleons by high-energy electrons is propounded as a tool for checking microscopical model ($^3P_0$ - fluctuation) for decay of N to different channels $π+B$ and Preparata model of nucleus structure.
Background: Exclusive two-nucleon knockout after electroexcitation of nuclei ($A(e,e'NN)$ in brief) is considered to be a primary source of information about short-range correlations (SRC) in nuclei. For a proper interpretation of the data, final-state interactions (FSI) need to be theoretically controlled. Purpose: Our goal is to quantify the role of FSI effects in exclusive $A(e,e'pN)$ reactions for four target nuclei representative for the whole mass region. Our focus is on processes that are SRC driven. We investigate the role of FSI for two characteristic detector setups corresponding wit…
The cross section for exclusive $π^+π^-$ and $π^0π^0$ meson pairs production in peripheral ultrarelativistic heavy-ion collisions is calculated at the energy available at the CERN Large Hadron Collider, i.e., $\sqrt{s_{NN}}=3.5$ TeV. The cross section for elementary $γγ\toππ$ process is calculated with the help of the pQCD Brodsky-Lepage approach with the distribution amplitude used recently to describe the pion transition form factor measured by the BaBar Collaboration.
The contributions from $^{12}$C$(e,e'pn)$ and $^{12}$C$(e,e'pp)$ to the semi-exclusive $^{12}$C$(e,e'p)$ cross section have been calculated in an unfactorized model for two-nucleon emission. We assume direct two-nucleon knockout after virtual photon coupling with the two-body pion-exchange currents in the target nucleus. Results are presented at several kinematical conditions in the dip and $Δ$(1232) regions. The calculated two-nucleon knockout strength is observed to account for a large fraction of the measured $(e,e'p)$ strength above the two-nucleon emission threshold.
Knockout nuclear reactions, in which a nucleon is removed from a nucleus as a result of the collision with another nucleus, have been widely used as an experimental tool, both to populate isotopes further removed from stability, and to obtain information about the single-particle nature of the nuclear spectrum. In order to fully exploit the experimental information, theory is needed for the description of both the structure of the nuclei involved, and the dynamics associated with the nucleon removal mechanisms. The standard approach, using theoretical shell-model spectroscopic factors for the …
The role of center-of mass (CM) effects in the one-body nuclear current in the description of electromagnetically induced two-nucleon knockout reactions is discussed in connection with the problem of the lack of orthogonality between initial bound states and final scattering states obtained by the use of an energy-dependent optical model potential. Results for the cross sections of the exclusive $^{16}$O(e,e$'$pp)$^{14}$C and $^{16}$O($γ$,pp)$^{14}$C knockout reactions in different kinematics are presented and discussed. In super-parallel kinematics CM effects produce a strong enhancement of t…
The analysis of the sample of charged current quasi elastic events collected by the MiniBooNE Collaboration suggests that the scheme successfully employed to describe electron-nucleus scattering fails to explain neutrino-nucleus cross sections. I argue that, due to flux average, the double differential neutrino-nucleus cross section does not allow for a clearcut determination of the dominant reaction mechanism. A systematic study of the large body of electron scattering data may help to identify the processes, other than single nucleon knockout, contributing to the observed neutrino cross sect…
Background. Knockout reactions with proton targets provide an invaluable tool to access the properties of two-neutron halo nuclei. Recently, experimental results for the average opening angle as a function of the intrinsic neutron momentum in 11Li have shown a localization of dineutron correlations on the nucleus surface. Purpose. Study the model dependence and the effect of distortion and absorption on the opening angle distributions to assess the reliability of this observable to extract properties of Borromean two-neutron halo nuclei. Method. A quasifree sudden model is used to describe the…
Results of relativistic calculations of the direct knockout (DKO) mechanism for the photon induced removal of a proton from a target nucleus over a wide range of energies and nuclei are presented. Spectroscopic factors used in the calculations are fixed from consistent analyses of the quasifree electron scattering process (e,e'p). The results indicate that within the uncertainties of the model, the knockout contributions are generally close to the experimental data for missing momenta below approximately 500 MeV/c. This is in disagreement with nonrelativistic analyses which often find that the…
The cross sections of the ($e,e'N$) and ($γ,p$) reactions on $^{16}$O are calculated, for the transitions to the $1/2^{-}$ ground state and the first $3/2^{-}$ excited state of the residual nucleus, using single-particle overlap functions obtained on the basis of one-body density matrices within different correlation methods. The electron-induced one-nucleon knockout reaction is treated within a nonrelativistic DWIA framework. The theoretical treatment of the ($γ,p$) reaction includes both contributions of the direct knockout mechanism and of meson-exchange currents. The results are sensitive …
We show that gluon saturation gives rise to a strong modification of the scaling in both the nuclear mass number $A$ and the virtuality $Q^2$ of the vector meson production cross-section in exclusive deep-inelastic scattering off nuclei. We present qualitative analytic expressions for how the scaling exponents are modified as well as quantitative predictions that can be tested at an Electron-Ion Collider.
Electro-production of pions and kaons at the kinematics of quasi-elastic knockout (which is well known in the physics of atomic nucleus and corresponds to the $t$-pole diagram) is proposed for obtaining their momentum distribution (MD) in various channels of virtual decay $N \to B+π$, $B=N$, $Δ$, $N^*$, $N^{**}$, and $N \to Y+K$, $Y=Λ$, $Σ$. It is a powerful tool for investigation of a quark microscopic picture of the meson cloud in the nucleon. A model of scalar $q \bar{q}$ ($^3P_0$) fluctuation in the non-trivial QCD vacuum is used to calculate pion and kaon momentum distributions (MD) in th…
The cross sections for exclusive muon pair production in nucleus - nucleus collisions are calculated and several differential distributions are shown. Realistic (Fourier transform of charge density) charge form factors of nuclei are used and the corresponding results are compared with the cross sections calculated with monopole form factor often used in the literature and discussed recently in the context of higher-order QED corrections. Absorption effects are discussed and quantified. The cross sections obtained with realistic form factors are significantly smaller than those obtained with th…
The general formalism of nucleon recoil polarization in the (${\vec e},e'{\vec N}N$) reaction is given. Numerical predictions are presented for the components of the outgoing proton polarization and of the polarization transfer coefficient in the specific case of the exclusive $^{16}$O(${\vec e},e'{\vec p}p$)$^{14}$C knockout reaction leading to discrete states in the residual nucleus. Reaction calculations are performed in a direct knockout framework where final-state interactions and one-body and two-body currents are included. The two-nucleon overlap integrals are obtained from a calculatio…
Heavy nuclei at collider energies are a source of high energy Weizsaecker-Williams photons. This photon flux may be utilized to study high energy photon-nucleus interactions. Here we concentrate on the coherent diffractive production of heavy vector mesons on nuclear targets and show how it probes the unintegrated glue of the nucleus in the saturation domain. We present predictions for rapidity distributions of exclusive coherent J/Psi and Upsilon mesons which can be measured by the ALICE experiment at the LHC.
Results for the cross sections of the exclusive 16O(e,e'pn)14N and 16O(gamma,pn)14N knockout reactions are presented and discussed in different kinematics. In comparison with earlier work, a complete treatment of the center-of-mass (CM) effects in the nuclear one-body current is considered in connection with the problem of the lack of orthogonality between initial bound and final scattering states. The effects due to CM and orthogonalization are investigated in combination with different treatments of correlations in the two-nucleon overlap function and for different parametrizations of the tw…
The contribution of the $Δ$(1232) isobar to the electromagnetic current of the two-nucleon system and its role in ($γ$,NN) processes is investigated. The difference between the genuine $Δ$-excitation current and that part of the current connected to the deexcitation of a preformed $Δ$ in the target nucleus is stressed. The latter cannot lead to a resonant behaviour of matrix elements for energies in the $Δ$ region. The reaction $^{16}O(γ,pp)^{14}C$, where the $Δ$ contribution is dominant at intermediate energies, is considered. The large variations found in the cross sections for different tre…
Reactions that involve the direct and sudden removal of a pair of like or unlike nucleons from a fast projectile beam by a light target nucleus are considered. Specifically, we study the three two-nucleon removal channels from $^{12}${C} that populate final states in the $^{10}${Be}, $^{10}${B} and $^{10}${C} reaction residues. The calculated two-nucleon removal cross sections and the residue momentum distributions are compared with available high energy data at 250, 1050 and 2010 MeV per nucleon, data that are inclusive with respect to the bound final-states of the residues. The measured $np$…
We present the current status of the research activities of the Ghent group on neutrino-nucleus interactions. These consist in the modeling of some of the relevant neutrino-nucleus reaction channels at intermediate energies: low-energy nuclear excitations, quasielastic scattering, two-nucleon knockout processes and single-pion production. The low-energy nuclear excitations and the quasielastic peak are described using a Hartree-Fock-CRPA (continuum random phase approximation) model that takes into account nuclear long-range correlations as well as the distortion of the outgoing nucleon wave fu…
We present a full kinematic analysis of neutrino-nucleus charged current quasielastic interactions based on the Local Fermi Gas model and the Random PhaseApproximation. The model was implemented in the NEUT Monte Carlo framework, which allows us to investigate potentially measurable observables, including hadron distributions. We compare the predictions simultaneously to the most recent T2K and MINERvA charged current (CC) inclusive, CC0$π$ and transverse kinematic-imbalance variable results. We pursuit a microscopic interpretation of the relevant reaction mechanisms, with the aim of achieving…
Understanding of inclusive one-nucleon knockout reactions for long-lived fission fragments (LLFPs) is crucial for nuclear transmutation studies. However, the particle and heavy ion transport code system (PHITS) severely overshoots the inclusive one-nucleon knockout cross sections sigma_-1N. Therefore development of a reaction model for describing the inclusive one-nucleon knockout processes is necessary. A key is specification of the position and the momentum of a nucleon inside a nucleus to be struck by the incident nucleon. In this paper the semiclassical distorted wave model incorporating t…
The cross sections for the glueball candidates production in quasi-real photon-photon collisions and on central diffraction processes, i.e. double Pomeron exchange, in heavy ion interactions at RHIC and LHC are computed. The rates for these distinct production channels are compared and they may be a fruitful approach to the investigation of glueballs.
The exclusive $K^+$ meson production in a proton-nucleus collision, leading to two body final states, is investigated in a fully covariant two-nucleon model based on the effective Lagrangian picture. The explicit kaon production vertex is described via creation, propagation and decay into relevant channel of $N^*$(1650), $N^*$(1710) and $N^*$(1720) intermediate baryonic states in the initial collision of the projectile nucleon with one of its target counterparts which is modeled by the one-pion exchange process. The calculated cross sections show strong sensitivity to the medium effects on pio…
The nuclear structure dependence of direct reactions that remove a pair of like or unlike nucleons from a fast $^{12}$C projectile beam are considered. Specifically, we study the differences in the two-nucleon correlations present and the predicted removal cross sections when using $p$-shell shell-model and multi-$\hbarω$ no-core shell-model (NCSM) descriptions of the two-nucleon overlaps for the transitions to the mass $A$=10 projectile residues. The NCSM calculations use modern chiral two-nucleon and three-nucleon (NN+3N) interactions. The $np$-removal cross sections to low-lying $T$=0, $^{1…
The nucleon final-state interaction in inclusive electron-nucleus quasielastic scattering is studied. Based on the unitarity equation satisfied by the scattering-wave operators, a doorway model is developed to take into account the final-state interaction including the Pauli blocking of nucleon knockout. The model uses only experimental form factors as the input and can be readily applied to light- and medium-mass nuclei. Pauli blocking effects in these latter nuclei are illustrated with the case of the Coulomb interaction. Significant effects are noted for beam energies below ~ 350 MeV and fo…
We present a model for weak CC induced nuclear reactions at energies of interest for current and future neutrino oscillation experiments. This model is a natural extension of the work of Refs.[1,2], where the QE 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 …
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 attention to nuclear corrections besides Pauli blocking: Long and Short range nuclear correlations (RPA and SRC) and particle and hole Spectral Functions (SF). We also critically review the use of the Plane and Distorted Wave Impulse approximations (PWIA and DWIA) to describe inclusive one nucleon knockout reactions off nuclei. In this context, we present results from a Monte Carlo cascade method to acco…
Detecting neutrinos and extracting the information they bring along is an ambitions task that requires a detailed understanding of neutrino-nucleus interactions over a broad energy range. We present calculations for quasi-elastic neutrino-induced nucleon knockout reactions on atomic nuclei and neutrino-induced pion production reactions. In our models, final-state interactions are introduced using a relativistic multiple-scattering Glauber approximation (RMSGA) approach. For interactions at low incoming neutrino energies, long-range correlations are implemented by means of a continuum random ph…
We present our recent progress in the description of neutrino-nucleus interaction in the GeV region, of interest for ongoing and future oscillation experiments. In particular, we discuss the weak excitation of two-particle-two-hole states induced by meson exchange currents in a fully relativistic framework. We compare the results of our model with recent measurements of neutrino scattering cross sections, showing the crucial role played by two-nucleon knockout in the interpretation of the data.
The formalism describing (anti)neutrino-nucleus reaction cross-sections in neutral- and charged-current processes is improved. Compact formulae for the single-particle transition matrix elements, based on the multipole expansion treatment of the relevant hadronic currents and the use of harmonic oscillator basis, are presented. As an application, the nucleus $^{127}I$, a promising target for detection of solar- and supernova-neutrinos as well as of cold dark matter candidates, is considered. Our matrix elements refer to exclusive processes of the charge-changing $^{127}I(ν_l,l^-)^{127}Xe^{\sta…
The formalism to describe electron scattering reactions on two-neutron halo nuclei is developed. The halo nucleus is described as a three-body system (core+n+n), and the wave function is obtained by solving the Faddeev equations in coordinate space. We discuss elastic and quasielastic scattering using the impulse approximation to describe the reaction mechanism. We apply the method to investigate the case of electron scattering on $^6$He. Spectral functions, response functions, and differential cross sections are calculated for both neutron knockout and $α$ knockout by the electron.
We have studied a method to extract neutrino flux from the data of neutrino-nucleus reaction by using maximum entropy method. We demonstrate a promising example to extract neutrino flux from the inclusive cross section of muon production without selecting a particular reaction process such as quasi-elastic nucleon knockout.
Impact of Two-Body Currents on Semi-Exclusive Lepton-Nucleus Reactions
Fermilab（费米国家加速器实验室）；Instituto de Física Corpuscular (IFIC), CSIC‐Universitat de València（粒子物理研究所（IFIC），西班牙瓦伦西亚大学与西班牙高等科学研究理事会联合）；Argonne National Laboratory（阿贡国家实验室）
We address the issue of nuclear attenuation in nucleon and pion knockout reactions. A selection of results from a model based on a relativistic multiple-scattering approximation is presented. We show transparency calculations for pion electroproduction on several nuclei, where data are in very good agreement with calculations including color transparency. Secondly, we discuss the density dependence of reactions involving one or double proton knockout. The latter reaction succeeds in probing the high density regions in the deep interior of the nucleus.
The cross sections for exclusive $D^+D^-$ and $D^0 \bar {D^0}$ meson pair production in peripheral nucleus - nucleus collisions are calculated and several differential distributions are presented. The calculation of the elementary $γγ\to D \bar D$ cross section is done within the heavy-quark approximation and in the Brodsky- Lapage formalism with distribution amplitudes describing recent CLEO data on leptonic $D^+$ decay. Realistic (Fourier transform of charge density) charge form factors of nuclei are used to generate photon flux factors. Absorption effects are discussed and quantified. The c…
We study the impact of the description of the knockout nucleon wave function on electron- and neutrino-induced quasielastic and single-pion production cross sections. We work in a fully relativistic and quantum mechanical framework, where the relativistic mean-field model is used to describe the target nucleus. The focus is on Pauli blocking and the distortion of the final nucleon, these two nuclear effects are separated and analyzed in detail. We find that a proper quantum mechanical treatment of these effects is crucial to provide the correct magnitude and shape of the inclusive cross sectio…
New experimental data obtained from $γ$-ray tagged one-neutron and one-proton knockout from $^{55}$Co is presented. A candidate for the sought-after $T=1, T_z = 0, J^π = 6^+$ state in $^{54}$Co is proposed based on a comparison to the new data on $^{54}$Fe, the corresponding observables predicted by large-scale-shell-model (LSSM) calculations in the full $fp$-model space employing charge-dependent contributions, and isospin-symmetry arguments. Furthermore, possible isospin-symmetry breaking in the $A=54$, $T=1$ triplet is studied by calculating the experimental $c$ coefficients of the isobaric…
We investigate the helicity properties of the ejectile in quasi-elastic neutrino-induced nucleon-knockout reactions and consider the 12C target as a test case. A formalism based on a relativistic mean-field model is adopted. The influence of final-state interactions is evaluated within a relativistic multiple-scattering Glauber approximation (RMSGA) model. Our calculations reveal that the helicity asymmetries A_l in A(\overlineν,\overlineν'N) processes are extremely sensitive to strange-quark contributions to the weak vector form-factors. Thereby, nuclear corrections, such as final-state inter…
