37 research outputs found
Quasielastic electroweak scattering cross sections in kinematics relevant for accelerator-based neutrino-oscillation experiments
Low-energy neutrino-nucleus interactions and beta-beam neutrino
We present an overview of neutrino-nucleus scattering at low energies with cross sections obtained within a continuum random phase approximation (CRPA) formalism. We highlight potential applications of beta-beam neutrino experiments for neutrino astrophysics. Our calculations are compared with MiniBooNe data at intermediate energies
-dependence of quasielastic charged-current neutrino-nucleus cross sections
Background: 12C has been and is still widely used in neutrino-nucleus
scattering and oscillation experiments. More recently, 40Ar has emerged as an
important nuclear target for current and future experiments. Liquid argon time
projection chambers (LArTPCs) possess various advantages in measuring
electroweak neutrino-nucleus cross sections. Concurrent theoretical research is
an evident necessity. Purpose: 40Ar is larger than 12C, and one expects nuclear
effects to play a bigger role in reactions. We present inclusive differential
and total cross section results for charged-current neutrino scattering on 40Ar
and perform a comparison with 12C, 16O and 56Fe targets, to find out about the
A-dependent behavior of model predictions. Method: Our model starts off with a
Hartree-Fock description of the nucleus, with the nucleons interacting through
a mean field generated by an effective Skyrme force. Long-range correlations
are introduced by means of a continuum random phase approximation (CRPA)
approach. Further methods to improve the accuracy of model predictions are also
incorporated in the calculations. Results: We present calculations for 12C,
16O, 40Ar and 56Fe, showcasing differential cross sections over a broad range
of kinematic values in the quasielastic regime. We furthermore show flux-folded
results for 40Ar and we discuss the differences between nuclear responses.
Conclusions: At low incoming energies and forward scattering we identify an
enhancement in the 40Ar cross section compared to 12C, as well as in the high
(low ) region across the entire studied range. The
contribution to the folded cross section of the reaction strength at values of
lower than 50 MeV for forward scattering is sizeable.Comment: 9 pages, 8 figures ; complete revision of calculations with updated
discussion of results, Fig. 4 replaced, updated reference list, minor
typographical correction
Flavor-Dependent Radiative Corrections in Coherent Elastic Neutrino-Nucleus Scattering
We calculate coherent elastic neutrino-nucleus scattering cross sections on spin-0 nuclei (e.g. 40Ar and 28Si) at energies below 100 MeV within the Standard Model and account for all effects of permille size. We provide a complete error budget including uncertainties at nuclear, nucleon, hadronic, and quark levels separately as well as perturbative error. Our calculation starts from the four-fermion effective field theory to explicitly separate heavy-particle mediated corrections (which are absorbed by Wilson coefficients) from light-particle contributions. Electrons and muons running in loops introduce a non- trivial dependence on the momentum transfer due to their relatively light masses. These same loops, and those mediated by tau leptons, break the flavor universality because of mass-dependent electromagnetic radiative corrections. Nuclear physics uncertainties significantly cancel in flavor asymmetries resulting in subpercent relative errors. We find that for low neutrino energies, the cross section can be predicted with a relative precision that is competitive with neutrino-electron scattering. We highlight potentially useful applications of such a precise cross section prediction ranging from precision tests of the Standard Model, to searches for new physics and to the monitoring of nuclear reactors
CRPA calculations for neutrino-nucleus scattering : from very low energies to the quasielastic peak
International audienceWe present continuum random phase approximation calculations (CRPA) for neutrino-induced quasielastic scattering off atomic nuclei. The validity of our formalism is checked by a careful confrontation of its results with semi-inclusive double-differential electron scattering data. We pay special attention to excitations in the giant resonance region. The CRPA is well-suited for the description of interactions in this energy range. We aim at providing a uniform description of one-nucleon knockout processes over the whole energy range from threshold to the quasielastic peak. Our calculations point to the fact that low-energy and giant-resonance excitations provide a non-negligible contribution to the interaction strength, especially at forward lepton-scattering angles
Modeling quasielastic interactions of monoenergetic kaon decay-at-rest neutrinos
Monoenergetic muon neutrinos at 236 MeV are readily produced in intense
medium-energy proton facilities (2-3~GeV) when a positive kaon decays
at rest (KDAR; ). These neutrinos provide a
unique opportunity to both study the neutrino interaction and probe the nucleus
with a monoenergetic weak-interaction-only tool. We present cross section
calculations for quasielastic scattering of these 236~MeV neutrinos off
C and Ar, paying special attention to low-energy aspects of the
scattering process. Our model takes the description of the nucleus in a
mean-field (MF) approach as the starting point, where we solve Hartree-Fock
(HF) equations using a Skyrme type nucleon-nucleon interaction. Thereby, we
introduce long-range nuclear correlations by means of a continuum random phase
approximation (CRPA) framework where we solve the CRPA equations using a
Green's function method. The model successfully describes () data on
C and Ca in the kinematic region that overlaps with the KDAR
phase space. In addition to these results, we present future
prospects for precision KDAR cross section measurements and applications of our
calculations in current and future experiments that will utilize these
neutrinos
Correlations in neutrino-nucleus scattering
We present a detailed study of charged-current quasielastic neutrino-nucleus
scattering and of the influence of correlations on one- and two-nucleon
knockout processes. The quasielastic neutrino-nucleus scattering cross
sections, including the influence of long-range correlations, are evaluated
within a continuum random phase approximation approach. The short-range
correlation formalism is implemented in the impulse approximation by shifting
the complexity induced by the correlations from the wave functions to the
operators. The model is validated by confronting cross-section
predictions with electron scattering data in the kinematic region where the
quasielastic channel is expected to dominate. Further, the
C experiments are studied. Double differential cross
sections relevant for neutrino-oscillation C cross
sections, accounting for long- and short-range correlations in the one-particle
emission channel and short-range correlations in the two-particle two-hole
channel, are presented for kinematics relevant for recent neutrino-nucleus
scattering measurements.Comment: 10 pages, 4 figures. Contribution to the proceedings of the 17th
International Workshop on Neutrino Factories and Future Neutrino Beam
Facilities (NUFACT-2015
Influence of short-range correlations in neutrino-nucleus scattering
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 C target
at energies relevant for contemporary measurements. Method: The model adopted
in this work, corrects the impulse approximation for SRCs by shifting the com-
plexity induced by the SRCs from the wave functions to the operators. Due to
the local character of the SRCs, it is argued that the expansion of these
operators can be truncated at a low order. Results: The model is compared with
electron-scattering data, and two-particle two-hole responses are presented for
neutrino scattering. The contributions from the vector and axial-vector parts
of the nuclear current as well as the central, tensor and spin-isospin part of
the SRCs are studied. Conclusions: Nuclear SRCs affect the 1N knockout channel
and give rise to 2N knockout. The exclusive neutrino-induced 2N knockout cross
section of SRC pairs is shown and the 2N knockout contribution to the QE signal
is calculated. The strength occurs as a broad background which extends into the
dip region.Comment: 16 pages, 10 figures. Version published in Physical Review
Electron versus muon neutrino induced cross sections in charged current quasi-elastic processes
Differences between and quasielastic cross sections are
essential in neutrino oscillation analyses and CP violation searches for
experiments such as DUNE and T2HK. The ratio of these is however poorly known
experimentally and for certain kinematic regions theoretical models give
contradictory answers. We use two independent mean-field based models to
investigate this ratio using Ar and C targets. We demonstrate
that a proper treatment of the final nucleon's wave function confirms the
dominance of over induced cross sections at forward lepton
scattering.Comment: Updated Fig. 2, minor changes to text, accepted for publication in
Phys. Rev. Letter