Methods to determine neutrino flux at low energies

Abstract

We investigate the "low-ν" method (developed by the CCFR/NUTEV collaborations) to determine the neutrino flux in a wide band neutrino beam at very low energies, a region of interest to neutrino oscillations experiments. Events with low hadronic final state energy ν < ν cut (of 1, 2 and 5 GeV) were used by the MINOS collaboration to determine the neutrino flux in their measurements of neutrino (ν μ ) and antineutrino (ν μ ) total cross sections. The lowest ν μ energy for which the method was used in MINOS is 3.5 GeV, and the lowestν μ energy is 6 GeV. At these energies, the cross sections are dominated by inelastic processes. We investigate the application of the method to determine the neutrino flux for ν μ ,ν μ energies as low as 0.7 GeV where the cross sections are dominated by quasielastic scattering and Δ(1232) resonance production. We find that the method can be extended to low energies by using ν cut values of 0.25 and 0.50 GeV, which are feasible in fully active neutrino detectors such as MINERvA.

Using Drell–Yan forward–backward asymmetry to reduce PDF uncertainties in the measurement of electroweak parameters

“…In addition, there are new techniques that can be used [16,17] to greatly reduce the experimental systematic uncertainty in asymmetry measurements.…”

Measurements of the inclusive neutrino and antineutrino charged current cross sections in MINERvA using the low- ν flux method

“…If one limits the final-state phase space to events with ν less than some cutoff ν 0 (where ν 0 ≪ E ν ) the terms proportional to ν=E ν , ν=E 2 ν , and ν 2 =E 2 ν are small, yielding a cross section that is approximately constant as a function of neutrino energy. The low-ν restricted cross section deviates from a constant value both due to the finite value of ν 0 in practical applications and due to the small Q 2 dependence (Bjorken scaling violation) of the structure functions [19]. While the formulation in Eq.…”

Extraction of neutrino flux with the low ν method at MiniBooNE energies

“…If nuclear transverse enhancement in the vector form factors is accounted for, the data are best fit with a modified dipole form factor with M A = 1.10 ± 0.03 GeV. In a previous communication [1] we present the application of the 'low-ν' method to the extraction of neutrino (ν µ ) flux for energies (E ν ) as low as 0.7 GeV. In this paper we extend the technique to E ν as low as 0.4 GeV and extract the relative energy dependence of the ν µ flux for the MiniBooNE experiment as an example.…”

“…At low-ν, if we integrate the cross section from ν min ≈ 0 up to ν= ν cut (where ν cut is small), we can write the 'low-ν' cross section [1] in terms of an energy independent term which is proportional to the structure function W 2 , and small energy dependent corrections which are proportional to ν/E, or m 2 µ /E 2 where m − µ is the mass of the muon.…”

“…where σ 4 and σ 5 are negligible [1], and M is the nucleon mass. The uncertainties in the modeling of the small energy dependent correction terms are small, thus we can extract the relative ν µ flux from the number of low-ν events at each E ν bin.…”