Ab Initio Study of (νℓ,ℓ−) and (ν¯<

Abstract

We carry out an ab initio calculation of the neutrino flux-folded inclusive cross sections measured on 12 C by the MiniBooNE and T2K Collaborations in the charged-current quasielastic regime. The calculation is based on realistic two-and three-nucleon interactions, and on a realistic nuclear electroweak current with one-and two-nucleon terms that are constructed consistently with these interactions and reproduce lowenergy electroweak transitions. Numerically exact quantum Monte Carlo methods are utilized to compute the nuclear weak response functions, by fully retaining many-body correlations in the initial and final states and interference effects between one-and two-body current contributions. We employ a nucleon axial form factor of the dipole form with Λ A ¼ 1.0 or 1.15 GeV, the latter more in line with a very recent lattice QCD determination. The calculated cross sections are found to be in good agreement with the neutrino data of MiniBooNE and T2K, and antineutrino MiniBooNE data, yielding a consistent picture of nuclei and their electroweak properties across a wide regime of energy and momenta.

Quasielastic electromagnetic scattering cross sections and world data comparisons in the GENIE Monte Carlo event generator

“…where ψ nr ≡ ψ nr (|q|, ω) is a nonrelativistic scaling variable [54,62], R nr α (|q i | ∈ Q, ω) is a known nonrelativistic nuclear response function for a particular component α from a known computed set [3] Note that Ref. [54] shares a common theoretical basis with inputs used in this work [3], and also shows that good scaling behavior persists even with the inclusion of two-body dynamics. When comparing to the originally computed longitudinal nuclear response functions, this method partially removes some endemic contamination of the elastic scattering component, which would otherwise lead to over-estimations of longitudinal response function at low momentum transfers (q 300 MeV).…”

“…(18) appears in discussions within Ref. [54], while previous discussions such as those in Ref. [63] did not take into account this small binding energy shift; removal of this shift does significantly change the scaling behavior.…”

“…Quantum Monte Carlo computational methods [11] have been developed for the past 30 years to exactly solve the many-body nuclear problem of strongly correlated nucleons. Inclusive response functions, induced by both electrons and νs, have been calculated in recent year for nuclei up to 12 C [22,23,[49][50][51][52][53][54]. In particular, one evaluates the Laplace transform of the response [11,22] which results in an imaginary-time response of the type…”

“…Here, we will expound more technically on elements of our interpolation techniques, including the scaling and alignment behavior of our given nuclear response functions [3]. Studies of these properties in the QMC STA response functions can be completed utilizing the nonrelativistic formalisms within [23,54,[62][63][64]68]; this is appropriate, as relativistic effects on such responses (such as a broadening of the QE response distribution) have been shown previously to be rather small [64] in many QE-like kinematic regimes, and because the STA itself is currently conceived within a nonrelativistic framework.…”

Weak Transitions in Light Nuclei

“…For example, calculations of total and partial muon-capture rates and comparisons with the known experimental data will probe our model at intermediate values of momentum transfer and will be the subject of our future work. At higher energies, neutrino-nucleus cross sections calculations [33,34] are the main input to interpret the data from long and short baseline neutrino-oscillation experiments, which use nuclei as active material in the detectors. Specifically, current challenges concern the implementation of microscopic models of nuclear dynamics-that fully capture correlation effects-in neutrino event generators [35] used to simulate the neutrino interaction physics.…”