The three-flavor neutrino oscillation paradigm is well established in particle physics thanks to the crucial contribution of accelerator neutrino beam experiments. In this paper we review the most important contributions of these experiments to the physics of massive neutrinos after the discovery of $θ_{13}$ and future perspectives in such a lively field of research. Special emphasis is given to the technical challenges of high power beams and the oscillation results of T2K, OPERA, ICARUS and NO$ν$A. We discuss in details the role of accelerator neutrino experiments in the precision era of neutrino physics in view of DUNE and Hyper-Kamiokande, the programme of systematic uncertainty reduction and the development of new beam facilities.
If a sterile neutrino nu_s with an eV-scale mass and a sizeable mixing to the electron neutrino exists, as indicated by the reactor and gallium neutrino anomalies, a strong resonance enhancement of nu_e-nu_s oscillations of atmospheric neutrinos should occur in the TeV energy range. At these energies neutrino flavour transitions in the 3+1 scheme depend on just one neutrino mass squared difference and are fully described within a 3-flavour oscillation framework. We demonstrate that the flavour transitions of atmospheric nu_e can actually be very accurately described in a 2-flavour framework, w…
In this contribution, we summarise the determination of neutrino masses and mixing arising from global analysis of data from atmospheric, solar, reactor, and accelerator neutrino experiments performed in the framework of three-neutrino mixing and obtained in the context of the NuFIT collaboration. Apart from presenting the latest status as of autumn 2021, we discuss the evolution of global-fit results over the last 10 years, and mention various pending issues (and their resolution) that occurred during that period in the global analyses.
The neutrino oscillation probabilities at the long-baseline accelerator neutrino experiments are expected to be modified by matter effects. We search for evidence of such modification in the data of T2K and NO$ν$A, by fitting the data to the hypothesis of (a) matter modified oscillations and (b) vacuum oscillations. We find that vacuum oscillations provide as good a fit to the data as matter modified oscillations. Even extended runs of T2K and NO$ν$A, with 5 years in neutrino mode $(5 ν)$ and five years in anti-neutrino mode $(5 \barν)$, can {\bf not} make a $3~σ$ distinction between vacuum an…
We consider the interplay of fundamental and matter-induced T violation effects in neutrino oscillations in matter. After discussing the general features of these effects we derive a simple approximate analytic expression for the T-violating probability asymmetry ΔP^T_{ab} for three-flavour neutrino oscillations in a matter with an arbitrary density profile in terms of the two-flavour neutrino amplitudes. Explicit examples are given for the cases of a two-layer medium and for the adiabatic limit in the general case. We then discuss implications of the obtained results for long baseline experim…
A brief overview of selected topics in the theory and phenomenology of neutrino oscillations is given. These include: oscillations in vacuum and in matter; phenomenology of 3-flavour neutrino oscillations and effective 2-flavour approximations; CP and T violation in neutrino oscillations in vacuum and in matter; matter effects on ν_μ\leftrightarrow ν_τoscillations; parametric resonance in neutrino oscillations inside the earth; oscillations below and above the MSW resonance; unsettled issues in the theory of neutrino oscillations.
In this paper, we have analysed the latest data from NO$ν$A and T2K with the Lorentz invariance violation along with the standard oscillation hypothesis. We have found that the NO$ν$A data cannot distinguish between the two hypotheses at $1\, σ$ confidence level. T2K data and the combined data analysis excluded standard oscillation at $1\, σ$. All three cases do not have any hierarchy sensitivity when analysed with LIV. There is a mild tension between the two experiments, when analysed with LIV, as $θ_{23}$ at \nova best-fit is at higher octant but the same for T2K is at lower octant. NO$ν$A h…
A new experimental technique to study the decays of $B^0_s$ mesons into final states involving unreconstructable particles is proposed. The method uses a characteristic feature of fast flavour oscillations of $B^0_s$ mesons. Analysis of the oscillation-frequency spectrum of partially reconstructed flavour-tagged $B^0_s$ decays provides information about the mass spectrum of unreconstructed decay products and suppresses any background that does not come from the decays of $B^0_s$ mesons.
CP-violation or Nuclear Excitation: Reviewing the Role of Neutrino Interaction Model Uncertainties on Accelerator-Based Neutrino Oscillation Measurements
Given an accelerator-based neutrino experiment with the beam energy E \lesssim 1 GeV, we expand the probabilities of ν_μ\to ν_e and \overline ν_μ\to \overline ν_e oscillations in matter in terms of two small quantities Δ_{21}/Δ_{31} and A/Δ_{31}, where Δ_{21} \equiv m^2_2 - m^2_1 and Δ_{31} \equiv m^2_3 - m^2_1 are the neutrino mass-squared differences, and A measures the strength of terrestrial matter effects. Our analytical approximations are numerically more accurate than those made by Freund in this energy region, and thus they are particularly applicable for the study of leptonic CP viola…
This paper summarises a few selected topics discussed during Working Group 5 of the Deep Inelastic Scattering 2017 conference, Physics with Heavy Flavours, related to the study of charm, bottom, and top quark physics. While the programme of this Working Group was structured by thematic areas, this conference was the occasion for intense cross-pollination between traditionally disjoint research lines. The four LHC experiments all contribute to heavy-flavour physics, with some degree of overlap in most areas, while experiments at other accelerators provide vital input in complimentary kinematic …
We present the results of a global analysis of the neutrino oscillation data available as of fall 2018 in the framework of three massive mixed neutrinos with the goal at determining the ranges of allowed values for the six relevant parameters. We describe the complementarity and quantify the tensions among the results of the different data samples contributing to the determination of each parameter. We also show how those vary when combining our global likelihood with the chi^2 map provided by Super-Kamiokande for their atmospheric neutrino data analysis in the same framework. The best fit of …
European facilities for accelerator neutrino physics: perspectives for the decade to come
很快，新一代的反应堆和加速器中微子振荡实验--双中微子、大亚湾、里诺和T2 K--将寻找由混合参数θ_13产生的振荡信号。这个角度的知识是一个基本的里程碑，以优化进一步的实验，旨在检测CP破坏的中微子部门。轻子CP破坏是一个在粒子物理学和宇宙学中具有深远意义的关键现象，但它显然是上述实验无法达到的。90年代末以来，世界范围内的一项活动正在进行中，即设计能够探测中微子振荡中CP破坏的装置，并对Cabibbo-Kobayashi-Maskawa矩阵的轻子对应物进行高精度测量。本文将总结这些研究的现状，重点是最适合利用现有欧洲设施（首先是CERN和INFN Gran Sasso实验室）或欧洲拥有世界领先地位的技术的选择。类似的考虑将在更奇异的场景中发展-超出三个活跃中微子之间的味道振荡的标准框架-这可能在MiniBooNE实验或CNGS后出现异常结果时似乎是合理的。
We perform a combined fit to global neutrino oscillation data available as of fall 2016 in the scenario of three-neutrino oscillations and present updated allowed ranges of the six oscillation parameters. We discuss the differences arising between the consistent combination of the data samples from accelerator and reactor experiments compared to partial combinations. We quantify the confidence in the determination of the less precisely known parameters $θ_{23}$, $δ_\text{CP}$, and the neutrino mass ordering by performing a Monte Carlo study of the long baseline accelerator and reactor data. We…
The T2K experiment is a long-baseline accelerator neutrino experiment using a near detector complex ND280 and a far detector, Super-Kamiokande. Neutrino interactions are detected by Cherenkov light in Super-Kamiokande in order to measure neutrino oscillation parameters. The accuracy of the oscillation parameter measurements depends on our knowledge of neutrino interactions, the neutrino flux and the detector response. ND280 is composed of a tracker and several sub-detectors designed to characterise the neutrino beam before oscillation, which allow us to constrain the uncertainties on the neutr…
