Charged-current Neutrino Interactions Research Articles

Measurement of inclusive double-differential νμ charged-current cross section with improved acceptance in the T2K off-axis near detector

We report a measurement of the flux-integrated cross section for inclusive muon neutrino charged-current interactions on carbon. The double differential measurements are given as function of the muon momentum and angle. Relative to our previous publication on this topic, these results have an increased angular acceptance and higher statistics. The data sample presented here corresponds to $5.7 \times 10^{20}$ protons-on-target. The total flux-integrated cross section is measured to be $(6.950 \pm 0.662) \times 10^{-39}$ cm$^2$nucleon$^{-1}$ and is consistent with our simulation.

Final results of the search for \u03bd\u03bc \u2192 \u03bde oscillations with the OPERA detector in the CNGS beam

The OPERA experiment has discovered the tau neutrino appearance in the CNGS muon neutrino beam, in agreement with the 3 neutrino flavour oscillation hypothesis. The OPERA neutrino interaction target, made of Emulsion Cloud Chambers, was particularly efficient in the reconstruction of electromagnetic showers. Moreover, thanks to the very high granularity of the emulsion films, showers induced by electrons can be distinguished from those induced by π0s, thus allowing the detection of charged current interactions of electron neutrinos. In this paper the results of the search for electron neutrino events using the full dataset are reported. An improved method for the electron neutrino energy estimation is exploited. Data are compatible with the 3 neutrino flavour mixing model expectations and are used to set limits on the oscillation parameters of the 3+1 neutrino mixing model, in which an additional mass eigenstate m4 is introduced. At high Δm412 (≳0.1 eV2), an upper limit on sin2 2θμe is set to 0.021 at 90% C.L. and Δm412 ≳ 4 × 10− 3 eV2 is excluded for maximal mixing in appearance mode.

First Measurement of Monoenergetic Muon Neutrino Charged Current Interactions.

We report the first measurement of monoenergetic muon neutrino charged current interactions. MiniBooNE has isolated 236MeV muon neutrino events originating from charged kaon decay at rest (K^{+}→μ^{+}ν_{μ}) at the NuMI beamline absorber. These signal ν_{μ}-carbon events are distinguished from primarily pion decay in flight ν_{μ} and ν[over ¯]_{μ} backgrounds produced at the target station and decay pipe using their arrival time and reconstructed muon energy. The significance of the signal observation is at the 3.9σ level. The muon kinetic energy, neutrino-nucleus energy transfer (ω=E_{ν}-E_{μ}), and total cross section for these events are extracted. This result is the first known-energy, weak-interaction-only probe of the nucleus to yield a measurement of ω using neutrinos, a quantity thus far only accessible through electron scattering.

Publisher’s Note: Measurement of the antineutrino to neutrino charged-current interaction cross section ratio in MINERvA [Phys. Rev. D 95 , 072009 (2017)

Publisher’s Note: Measurement of the antineutrino to neutrino charged-current interaction cross section ratio in MINERvA [Phys. Rev. D <b>95</b> , 072009 (2017)

Study of charged hadron multiplicities in charged-current neutrino\u2013lead interactions in the OPERA detector

The OPERA experiment was designed to search for nu _{mu } rightarrow nu _{tau } oscillations in appearance mode through the direct observation of tau neutrinos in the CNGS neutrino beam. In this paper, we report a study of the multiplicity of charged particles produced in charged-current neutrino interactions in lead. We present charged hadron average multiplicities, their dispersion and investigate the KNO scaling in different kinematical regions. The results are presented in detail in the form of tables that can be used in the validation of Monte Carlo generators of neutrino–lead interactions.

Sensitivities to charged-current nonstandard neutrino interactions at DUNE

We investigate the effects of charged-current (CC) nonstandard neutrino interactions (NSIs) at the source and at the detector in the simulated data for the planned Deep Underground Neutrino Experiment (DUNE). We neglect the neutral-current NSIs at the propagation because several solutions have already been proposed for resolving the degeneracies posed by neutral-current NSIs but no solutions exist for the degeneracies due to the CC NSIs. We study the effects of CC NSIs on the simultaneous measurements of and in DUNE. The analysis reveals that 3σ C.L. measurement of the correct octant of in the standard mixing scenario is spoiled if the CC NSIs are taken into account. Likewise, the CC NSIs can deteriorate the uncertainty of the measurement by a factor of two relative to that in the standard oscillation scenario. We also show that the source and the detector CC NSIs can induce a significant amount of fake CP-violation and the CP-conserving case can be excluded by more than 80% C.L. in the presence of fake CP-violation. We further find DUNE’s potential for constraining the relevant CC NSI parameters from the single parameter fits for both neutrino and antineutrino appearance and disappearance channels at both the near and far detectors. The results show that there could be improvements in the current bounds by at least one order of magnitude at DUNE’s near and far detectors, except for a few parameters which remain weaker at the far detector.

First all-flavor neutrino pointlike source search with the ANTARES neutrino telescope

A search for cosmic neutrino sources using the data collected with the ANTARES neutrino telescope between early 2007 and the end of 2015 is performed. For the first time, all neutrino interactions --charged and neutral current interactions of all flavours-- are considered in a search for point-like sources with the ANTARES detector. In previous analyses, only muon neutrino charged current interactions were used. This is achieved by using a novel reconstruction algorithm for shower-like events in addition to the standard muon track reconstruction. The shower channel contributes about 23\% of all signal events for an $E^{-2}$ energy spectrum. No significant excess over background is found. The most signal-like cluster of events is located at $(\alpha,\delta) = (343.8^\circ, 23.5^\circ)$ with a significance of $1.9\sigma$. The neutrino flux sensitivity of the search is about $E^2 d\varPhi/dE = 6\cdot10^{-9} GeV cm^{-2} s^{-1}$ for declinations from $-90^\circ$ up to $-42^\circ$, and below $10^{-8} GeV cm^{-2} s^{-1}$ for declinations up to $5^{\circ}$. The directions of 106 source candidates and of 13 muon track events from the IceCube HESE sample are investigated for a possible neutrino signal and upper limits on the signal flux are determined.

Neutrino cross-section in ultrahigh energy regime using double asymptotic limit of QCD

Studies on neutrino–nucleon (\({\nu }N\)) cross-sections have regained interest due to increasing importance of precision measurements, as they are needed as an ingredient in all neutrino experiments. In this work, we use the QCD-inspired double asymptotic limit fit of electron–proton structure function \(F_{2}^{ep}\) to low-\( x \) HERA data, to calculate \(\nu \) N cross-section for charged current (CC) and neutral current (NC) neutrino interactions in ultrahigh energy (UHE) neutrino energy (\(E_{\nu }\)) regime (\(10^{9}\, \mathrm {GeV} \le E_{\nu } \le 10^{12}\, \mathrm {GeV} \)). The form \(F_{2}^{ep} \sim x^{-\lambda (Q^{2})}\), used in our analysis, can be conjectured like a dynamic pomeron (DP)-type behaviour. We also find an analytic form of the total cross-sections, \(\sigma _{\mathrm {CC}}^{\nu N}\) and \(\sigma _{\mathrm {NC}}^{\nu N}\), which appear to be of Reggeon exchange type. We also do a comparative analysis of our results with those available in literature. Future measurements will support / confront our predictions.

Astrophysical neutrinos: IceCube highlights

The IceCube Neutrino Observatory features approximately a cubic-kilometer volume of instrumented ice at the geographic South Pole. A high energy astrophysical neutrino flux has been observed, initially in 2013, as an excess of neutrinos above 10 TeV compared to the expectation from an atmospheric neutrino background. This signal, nowadays significant at >6 σ, has been observed both in neutrino interactions starting in the detector volume and in throughgoing muons generated in charged-current muon neutrino interactions outside the detector. No astrophysical objects have yet been identified as the flux source, which is currently consistent with an isotropic expectation. This paper reviews the evidence for the astrophysical flux and the status of the search for its sources. It also presents a discussion of proposed detector extensions being designed to solve the mystery of the astrophysical neutrino origin.

Measurement of the nu _{mu } energy spectrum with IceCube-79

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The nu _mu energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E_nu -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9,sigma in four adjacent bins for neutrino energies E_nu ge 177.8,text {TeV}. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.

Measurements of muon neutrino charged-current interactions by the MicroBooNE experiment

MicroBooNE is a 170 ton Liquid Argon Time Projection Chamber (LArTPC) experiment located at Fermi National Accelerator Laboratory. It has been operating in the Booster neutrino beam since October 2015 and is already demonstrating the superb imaging capabilities of LArTPC detectors. MicroBooNE is the first large LArTPC detector to be exposed to a high-intensity neutrino beam. Among its primary physics goals are precise measurements of muon neutrino charged-current (CC) interactions on argon. In order to analyse its high-statistics data, a suite of fully automated techniques have been developed that reconstruct the LArTPC images and separate muon neutrino CC interactions from their cosmic-ray and neutral current backgrounds. These proceedings will describe the reconstruction and selection of muon neutrino CC event candidates, and present measured distributions of the observed events based on 5e19 protons on target from the first MicroBooNE data-taking period.

Benefits of Gd for High Energy Neutrinos in SuperK-Gd

The SuperK-Gd project is the approved upgrade of the Super-Kamiokande (SK) detector in order to enable it to efficiently (> 80%) detect thermal neutrons by dissolving 0.2% of gadolinium sulphate (Gd2(SO4)3) into its water. This ability has also significant advantages in the analysis of high energy (> 102 MeV) neutrinos in SK, namely atmospheric and long baseline neutrinos from T2K.Here we present the improvements due to the use of the tagged final state neutrons in the separation of the interacting neutrinos and antineutrinos, the distinction between Neutral Current and Charged Current neutrino interactions, and the neutrino energy reconstruction. We study the impact of those features on both, atmospheric and long baseline neutrino oscillation analyses.

Charged-current muon neutrino shape and rate analysis at the T2K off-axis near detector

The experimental evidence that neutrinos can convert from one flavour to another and therefore have non-vanishing mass, has been recently honoured by a Nobel Prize. However, the completeness of the three-neutrino mixing paradigm, parametrised by the PMNS matrix, was challenged in the last two decades. Sterile neutrinos - singlet fermions that contribute to weak interactions only through mixing with active neutrinos - might help to explain some anomalies to the three-neutrino scenario reported by several experiments. However, the existing results are puzzling and the existence of such particles is still an open question.The T2K off-axis near detector (ND280), located at 280m from the proton target, can contribute to the search for sterile neutrinos. Shape and rate measurements for charged-current muon neutrino interactions are studied and tested against the current cross-section model uncertainties to see whether it’s possible to detect short-baseline neutrino oscillations within the 3+1 model.

Charged current neutrino interactions in hot and dense matter

We derive the charged current absorption rate of electron and anti-electron neutrinos in dense matter using a fully relativistic approach valid at arbitrary matter degeneracy. We include mean field energy shifts due to nuclear interactions and the corrections due to weak magnetism. The rates are derived both from the familiar Fermi's Golden Rule, and from the techniques of finite temperature field theory, and shown to be equivalent. In various limits, these results can also be used to calculate neutral current opacities. We find that some pieces of the response have been left out in previous derivations and their contribution at high density can be significant. Useful formulae and detailed derivations are presented and we provide a new open source implementation of these opacities for use in radiation hydrodynamic simulations of core-collapse supernovae and neutron star mergers.

Measurement of the antineutrino to neutrino charged-current interaction cross section ratio in MINERvA

We present measurements of the neutrino and antineutrino total charged-current cross sections on carbon and their ratio using the MINERvA scintillator-tracker. The measurements span the energy range 2-22 GeV and were performed using forward and reversed horn focusing modes of the Fermilab low-energy NuMI beam to obtain large neutrino and antineutrino samples. The flux is obtained using a sub-sample of charged-current events at low hadronic energy transfer along with precise higher energy external neutrino cross section data overlapping with our energy range between 12-22 GeV. We also report on the antineutrino-neutrino cross section ratio, Rcc, which does not rely on external normalization information. Our ratio measurement, obtained within the same experiment using the same technique, benefits from the cancellation of common sample systematic uncertainties and reaches a precision of 5% at low energy. Our results for the antineutrino-nucleus scattering cross section and for Rcc are the most precise to date in the energy range $E_{\nu} <$ 6GeV.

Measurement of nuclear effects in neutrino interactions with minimal dependence on neutrino energy

We present a phenomenological study of nuclear effects in neutrino charged-current interactions, using transverse kinematic imbalances in exclusive measurements. Novel observables with minimal dependence on neutrino energy are proposed to study quasielastic scattering, and especially resonance production. They should be able to provide direct constraints on nuclear effects in neutrino- and antineutrino-nucleus interactions.

Measurement of double-differential muon neutrino charged-current interactions onC8H8without pions in the final state using the T2K off-axis beam

We report the measurement of muon neutrino charged-current interactions on carbon without pions in the final state at the T2K beam energy using 5.734$\times10^{20}$ protons on target. For the first time the measurement is reported as a flux-integrated, double-differential cross-section in muon kinematic variables ($\cos\theta_\mu$, $p_\mu$), without correcting for events where a pion is produced and then absorbed by final state interactions. Two analyses are performed with different selections, background evaluations and cross-section extraction methods to demonstrate the robustness of the results against biases due to model-dependent assumptions. The measurements compare favorably with recent models which include nucleon-nucleon correlations but, given the present precision, the measurement does not solve the degeneracy between different models. The data also agree with Monte Carlo simulations which use effective parameters that are tuned to external data to describe the nuclear effects. The total cross-section in the full phase space is $\sigma = (0.417 \pm 0.047 \text{(syst)} \pm 0.005 \text{(stat)})\times 10^{-38} \text{cm}^2$ $\text{nucleon}^{-1}$ and the cross-section integrated in the region of phase space with largest efficiency and best signal-over-background ratio ($\cos\theta_\mu>0.6$ and $p_\mu > 200$ MeV) is $\sigma = (0.202 \pm 0.0359 \text{(syst)} \pm 0.0026 \text{(stat)}) \times 10^{-38} \text{cm}^2$ $\text{nucleon}^{-1}$.

Analysis of muon and electron neutrino charged current interactions in the T2K near detectors

We present the updated measurement of the muon neutrino interaction rates and spectrum at the T2K near detector complex, ND280, located at the JPARC accelerator facility in Tokai, Japan, 280 meters downstream from the target. The measurements are obtained using all the data collected until 2014. The momentum-angle spectrum of muons from νμ charged current (CC) interactions measured at ND280 off-axis detector constrains the flux and cross-section uncertainties in the T2K oscillation analysis. This spectrum was also used to measure a differential cross-section measurement of muon neutrinos on carbon. Similarly the νe contamination of the T2K beam was measured to verify this intrinsic background for the electron neutrino appearance and provide the first electron neutrino cross-section result since the Gargamelle experiment. The νμ CC inclusive events selected in the on-axis detector (INGRID) at 280 m and originally used for monitoring the T2K beam stability were also used to measure the CC interaction cross sections on carbon and iron. The selections and results for both ND280 and INGRID will be presented in this paper as well as future prospects for both detectors.

Latest results on νμ → ντ oscillations from the OPERA experiment

The OPERA experiment is designed to prove neutrino oscillations in the νμ to ντ channel through the direct observation of the tau lepton in tau neutrino charged current interactions. The experiment has accumulated data for five years, from 2008 to 2012, with the CERN Neutrinos to Gran Sasso (CNGS), an almost pure νμ beam.In the last two years, a very large amount of the data accumulated in the nuclear emulsions has been analyzed. The latest results on oscillations with the increased statistics, which include a fourth tau neutrino candidate event, will be presented. Given the extremely low expected background, this result corresponds to the observation of the oscillation process with a four sigma level significance.

Search for astrophysical tau neutrinos in three years of IceCube data

The IceCube Neutrino Observatory has observed a diffuse flux of TeV-PeV astrophysical neutrinos at 5.7{\sigma} significance from an all-flavor search. The direct detection of tau neutrinos in this flux has yet to occur. Tau neutrinos become distinguishable from other flavors in IceCube at energies above a few hundred TeV, when the cascade from the tau neutrino charged current interaction becomes resolvable from the cascade from the tau lepton decay. This paper presents results from a dedicated search for tau neutrinos with energies between 214 TeV and 72 PeV. The analysis searches for IceCube optical sensors that observe two separate pulses in a single event - one from the tau neutrino interaction, and a second from the tau decay. This is the first IceCube tau neutrino search to be more sensitive to tau neutrinos than to any other neutrino flavor. No candidate events were observed in three years of IceCube data. For the first time, a differential upper limit on astrophysical tau neutrinos is derived around the PeV energy region, which is nearly three orders of magnitude lower in energy than previous limits from dedicated tau neutrino searches.