Search Results (24)

This paper aims to explore the implications of $U{\left(1\right)}_{L_e-L_{\alpha }}$ gauge symmetries, where $\alpha =\tau ,\mu$, in the neutrino sector through type-(I+II) seesaw mechanisms. To achieve such a hybrid framework, we include a scalar triplet and three right-handed neutrinos. The model can successfully account for the active neutrino masses, mixing angles, mass squared differences, and the CP-violating phase within the $3\sigma$ bounds of NuFit v5.2 neutrino oscillation data. The presence of a new gauge boson at the MeV scale provides an explanation for the muon and electron $(g-2)$ within the confines of their experimental limits. Furthermore, we scrutinize the proposed models in the context of upcoming long-baseline neutrino experiments such as DUNE, P2SO, T2HK, and T2HKK. The findings reveal that P2SO and T2HK have the ability to probe both models in their $5\sigma$-allowed oscillation parameter region, whereas DUNE and T2HKK can conclusively test only the model with $U{\left(1\right)}_{L_e-L_{\mu }}$-symmetry within the $5\sigma$ parameter space if the true values of the oscillation parameters remain consistent with NuFit v5.2. Full article

DUNE is a next-generation long-baseline neutrino oscillation experiment. It is expected to measure, with unprecedented precision, the atmospheric oscillation parameters, including the CP-violating phase ${\delta }_{CP}$. Moreover, several studies have suggested that its unique features should allow DUNE to probe several new physics scenarios. In this work, we explore the performances of the DUNE far detector in constraining new physics if a high-energy neutrino flux is employed (HE-DUNE). We take into account three different scenarios: Lorentz Invariance Violation (LIV), Long-Range Forces (LRFs) and Large Extra Dimensions (LEDs). Our results show that HE-DUNE should be able to set bounds competitive to the current ones and, in particular, it can outperform the standard DUNE capabilities in constraining CPT-even LIV parameters and the compactification radius $R_{ED}$ of the LED model. Full article

Long-baseline neutrino experiments represent the optimal platforms for probing the lepton Yukawa sector of the Standard Model, and significant experiments are either under construction or in the planning stages. This review delves into the scientific motivations behind these facilities, which stem from the pivotal 2012 discovery of the ${\theta }_{13}$ mixing angle. We provide an overview of the two ongoing projects, DUNE and HyperKamiokande, detailing their physics potential and the technical hurdles they face. Furthermore, we briefly examine proposals for forthcoming endeavors and innovative concepts that could push beyond conventional Superbeam technology. Full article

This paper presents a combined analysis of muon neutrino and antineutrino charged-current cross sections at kinematics of relevance for the T2K, MINERvA and MicroBooNE experiments. We analyze the sum, difference and asymmetry of neutrino versus antineutrino cross sections in order to get a better understanding of the nuclear effects involved in these processes. Nuclear models based on the superscaling behavior and the relativistic mean field theory are applied, covering a wide range of kinematics, from hundreds of MeV to several GeV, and the relevant nuclear regimes, i.e., from quasileastic reactions to deep inelastic scattering processes. The NEUT neutrino-interaction event generator, used in neutrino oscillation experiments, is also applied to the analysis of the quasielastic channel via local Fermi gas and spectral function approaches. Full article

The existence of a violation of the Charge-Parity (CP) symmetry in the laws of physics is one of the cornerstone conditions for the generation of a matter–antimatter imbalance necessary to the creation of a matter-dominated universe. The first experimental evidence of the fact that this symmetry is broken in nature was obtained in 1964 in the observations of the decays of neutral kaon mesons. The magnitude of CP violation in the quark sector was measured with an increasing precision exploring also decays of other mesons. However, CP violation in the quark sector alone is not sufficient to explain the formation of matter-dominated universe, and additional sources are required. One such potential source is the lepton sector, where the CP violation could be observed by studying neutrino oscillations with neutrino beams generated by particle accelerators. This article reviews the present efforts in this direction. The results obtained in the ongoing experiments, T2K in Japan and NOvA in USA, are discussed. Additionally, the search for leptonic CP violation is one of the key goals in the programs of future experiments, DUNE in USA and Hyper-Kamiokande in Japan. These experiments and their prospects for its discovery are also presented. Full article

We present compact analytic expressions for neutrino propagation probabilities in matter, with effects from the invisible decay of the ${\nu }_3$ mass eigenstate included. These will be directly relevant for long-baseline experiments. The inclusion of decay leads to a non-Hermitian effective Hamiltonian, with the Hermitian part corresponding to oscillation, and the anti-Hermitian part representing the decay. In the presence of matter, the two components invariably become non-commuting. We employ the Cayley–Hamilton theorem to calculate the neutrino oscillation probabilities in constant density matter. The analytic results obtained provide a physical understanding of the possible effects of neutrino decay on these probabilities. Certain non-intuitive features like an increase in the survival probability $P({\nu }_{\mu }\to {\nu }_{\mu })$ at its oscillation dips may be explained using our analytic expressions. Full article

In the search for the CP violation (CPV) in the leptonic sector, crucial information was obtained a decade ago from reactor and accelerator experiments. The discovery and measurement of the third neutrino mixing angle, ${\theta }_{13}$, with a value ∼9${}^{\circ }$, allow for the possibility to discover the leptonic Dirac CP-violating angle, ${\delta }_{CP}$, with long baseline neutrino Super Beams. ESS$\nu$SB is a long-baseline neutrino project that will be able to measure the CPV in the leptonic sector at the second oscillation maximum, where the sensitivity of the experiment is higher compared to that at the first oscillation maximum. The extension project, ESS$\nu$SB+, aims to address a very challenging task on measuring the neutrino–nucleon cross-section, which is the dominant term of the systematic uncertainty, in the energy range 0.2–0.6 GeV, using a Low-Energy nuSTORM (LEnuSTORM) and an ENUBET-like Low-Energy Monitored Neutrino Beam (LEMNB) facilities. The target station plays the main role in generating a well defined and focused pion, and hence muon, beam. Full article

T2K (Tokai to Kamioka) is a long baseline neutrino experiment that exploits a neutrino and antineutrino beam produced at the Japan Particle Accelerator Research Centre (J-PARC) to provide world-leading measurements of the parameters governing neutrino oscillation. Neutrino oscillations are analyzed by tuning the neutrino rates and spectra at a near detector complex, located at J-PARC, and extrapolating them to the water Cherenkov far detector, Super-Kamiokande, located 295 km away, where oscillations are observed. The latest T2K results include multiple analysis improvements, in particular, a new sample is added for the far detector analysis, requiring the presence of a pion in muon-neutrino interactions. This is the first time that a pion sample has been included in the study of neutrino disappearance at T2K and the first time a sample with more than one Cherenkov ring has been included in the T2K oscillation analysis, opening a road for further samples with charged and neutral pion tagging. The inclusion of such a sample enables proper control of the oscillated spectrum in a larger neutrino energy range and on subleading neutrino interaction processes. Finally, T2K is engaged with the Super-Kamiokande collaboration to combine T2K neutrino beam data and Super-Kamiokande atmospheric data to perform a joint fit of the oscillation parameters. Such a combination allows the degeneracies between the measurement of the CP-violating phase ${\delta }_{\mathrm{CP}}$ and the measurement of the ordering of the neutrino mass eigenstates to be lifted. A precise evaluation of the enhanced sensitivity of this joint fit will be presented. Full article

The High-Angle Time Projection Chambers (HA-TPCs) are a new set of detectors that will equip the off-axis near detector (ND280) of the T2K long-baseline neutrino oscillation experiment. A prototype of the Field Cage instrumented with one ERAM detector has been recently exposed to a DESY electron beam. In order to ensure that the HA-TPCs satisfy the required performances for the ND280 Upgrade (space point resolution better than 600 µm and dE/dx resolution smaller than 10%), the ERAM detectors have been characterized with X-ray sources and by exposing them to the DESY electron beam. In addition, a detailed simulation of the charge spreading phenomenon and of the electronic response is reported. Full article

The NuMI target facility at Fermilab produces an intense muon neutrino beam for the NOvA (NuMI Off-axis ${\nu }_e$ Appearance) long baseline neutrino experiment. Three arrays of muon monitors located downstream of the hadron absorber in the NuMI beamline provide the measurements of the primary beam and horn current quality. We have studied the response of muon monitors with the proton beam profile changes and focusing horn current variations. The responses of muon monitors are used to develop machine learning (ML) algorithms to monitor the beam quality. We present the development of the machine learning applications and future plans. This effort is important for future applications such as beam quality assurance, anomaly detection, and neutrino beam systematics studies. Our results demonstrate the advantages of developing useful ML applications that can be leveraged for future beamlines such as LBNF. Full article

The T2K experiment is a long baseline neutrino oscillation experiment conducted in Japan. It aims to precisely measure the neutrino oscillation parameters by measuring the muon neutrino beam produced at the J-PARC accelerator complex at both near and far detectors. The magnetized T2K near detector complex ND280 plays an important role in measuring the neutrino interactions before the oscillations and constraining the systematic uncertainties in the measurements of neutrino oscillation parameters. The physics goals of T2K are to test Charge-Parity (CP) symmetry in the lepton sector, to precisely measure the neutrino oscillation parameters ${\theta }_{23}$ and $\Delta m_{32}^2$, and to determine the neutrino mass ordering and the octant of ${\theta }_{23}$. T2K has disfavored CP conservation with a significance level of $2\sigma$, and the higher significance level can be achieved by increasing the statistics and reducing the systematic uncertainties. Thus, the T2K collaboration proposed upgrading ND280 by replacing the P0D detector with a new fine-grained scintillator detector SuperFGD and two Time-Projection Chambers (TPCs). In addition, these new detectors will be covered by six Time Of Flight (TOF) planes. The performances of these upgrade detectors have been tested and confirmed to satisfy the requirements of the ND280 upgrade program. The physics performances of the upgraded ND280 have also been studied and they show promising improvements in neutrino interaction measurements by introducing transverse kinematics variables. Full article

Long-baseline neutrino oscillation experiments rely on detailed models of neutrino interactions on nuclei. These models constitute an important source of systematic uncertainty, partially because detectors to date have been unable to detect final state neutrons. A novel three-dimensional projection scintillator tracker will be a component of the upgraded off-axis near detector of the T2K experiment. Due to the good timing resolution and fine granularity, this technology is capable of measuring neutron kinematics in neutrino interactions on an event-by-event basis and will provide valuable data for refining neutrino interaction models. A prototype is exposed to the neutron beamline at Los Alamos National Laboratory with neutron energies between 0 and 800 MeV. In order to demonstrate the capability to measure neutron kinematics, the total neutron–scintillator cross section as a function of the neutron kinetic energy is measured. Full article

The Jiangmen Underground Neutrino Observatory (JUNO) is a neutrino experiment under construction in an underground laboratory with a 650 m rock overburden near Jiangmen in southern China. The detector’s main component will be 20 kton of liquid scintillator held in a spherical acrylic vessel. The experiment is designed for the determination of neutrino mass ordering, one of the key open questions in neutrino physics. This measurement will be based on observations of the vacuum oscillation pattern of antineutrinos from two nuclear power plants at a baseline of 53 km. The estimated sensitivity is 3$\sigma$ in about six years with 26.6 GW${}_{\mathrm{th}}$ of reactor power. A key ingredient for the success is an excellent and extremely challenging energy resolution of 3% at 1 MeV. The light produced by the scintillator will be seen by 17,612 large twenty-inch PMTs and 25,600 small three-inch PMTs. The OSIRIS detector will monitor the radio purity of the liquid scintillator during the months-long filling process of the main detector. The unoscillated antineutrino spectrum from one reactor core will be measured with unprecedented precision by the Taishan Antineutrino Observatory (TAO), located at a baseline of about 30 m. JUNO is expected to substantially improve the precision of ${sin}^{2}2{\theta }_{12}$, $\Delta m_{21}^2$, and $\Delta m_{31}^2$ neutrino oscillation parameters. Astrophysical measurements of solar, geo-, supernova, DSNB, and atmospheric neutrinos, as well as searching for proton decay and dark matter, are integral parts of the vast JUNO physics program. This contribution reviews the physics goals and current status of the JUNO project. Full article

A detailed understanding of neutrino–nucleus interactions is essential for the precise measurement of neutrino oscillations at long baseline experiments, such as T2K. The T2K near detector complex, designed to constrain the T2K flux and cross-section models, also provides a complementary program of neutrino interaction cross-section measurements. Through the use of multiple target materials (carbon, water, lead, iron), and the ability to sample different neutrino spectra (with detectors located on- and off-axis with respect to the beam direction), T2K is able to investigate atomic number and energy dependence of interaction cross-sections in a single experiment. In particular, T2K has recently performed the first joint on-/off-axis measurement of the charged current channel without pion in the final state. Furthermore, dedicated efforts are devoted to investigating rare or poorly studied interaction channels. Indeed, an improved analysis of the coherent pion production cross-section was recently accomplished, including an anti-neutrino sample for the first time. Those results, together with an overview of the T2K measurement strategy, adopted to reduce the model dependence, will be presented in these proceedings. Full article

The neutrino mass ordering (NMO) is one of the last undetermined properties in the three-neutrino paradigm. NMO studies aim to answer the question of whether the neutrino mass ordering is normal ($m_3>m_2>m_1$) or inverted ($m_2>m_1>m_3$). We conduct a study of the NMO sensitivity with atmospheric neutrinos using 9.3 years of IceCube DeepCore data, where a new event selection, reconstruction method, particle identification, and systematic uncertainty modeling are used. The goals of this analysis consist of: (1) probing the NMO at neutrino baselines that are not accessible to long-baseline accelerator experiments, (2) contributing to NMO global fit studies in an important and unique way, (3) serving as a detailed study on the NMO in preparation for the upcoming IceCube Upgrade, which should significantly improve the DeepCore NMO sensitivity. Full article