scholarly journals A Comprehensive Study of the Discovery Potential of NOνA, T2K, and T2HK Experiments

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
C. Soumya ◽  
K. N. Deepthi ◽  
R. Mohanta

With the recent measurement of reactor mixing angleθ13the knowledge of neutrino oscillation parameters has improved significantly except the CP violating phaseδCP, mass hierarchy, and the octant of the atmospheric mixing angleθ23. Many dedicated experiments are proposed to determine these parameters which may take at least 10 years from now to become operational. It is therefore very crucial to use the results from the existing experiments to see whether we can get even partial answers to these questions. In this paper we study the discovery potential of the ongoing NOνA and T2K experiments as well as the forthcoming T2HK experiment in addressing these questions. In particular, we evaluate the sensitivity of NOνA to determine neutrino mass hierarchy, octant degeneracy, andδCPafter running for its scheduled period of 3 years in neutrino mode and 3 years in antineutrino mode. We then extend the analysis to understand the discovery potential if the experiments will run for (5ν+5ν¯) years and (7ν+3ν¯) years. We also show how the sensitivity improves when we combine the data from NOνA, T2K, and T2HK experiments with different combinations of run period. The CP violation sensitivity is marginal for T2K and NOνA experiments even for ten-year data taking of NOνA. T2HK has a significance above5σfor a fraction of two-fifths values of theδCPspace. We also find thatδCPcan be determined to be better than 35°, 21°, and 9° for all values ofδCPfor T2K, NOνA, and T2HK respectively.

2013 ◽  
Vol 2013 ◽  
pp. 1-29 ◽  
Author(s):  
Silvia Pascoli ◽  
Thomas Schwetz

Recently the last unknown lepton mixing angleθ13has been determined to be relatively large, not too far from its previous upper bound. This opens exciting possibilities for upcoming neutrino oscillation experiments towards addressing fundamental questions, among them the type of the neutrino mass hierarchy and the search for CP violation in the lepton sector. In this paper we review the phenomenology of neutrino oscillations, focusing on subleading effects, which will be the key towards these goals. Starting from a discussion of the present determination of three-flavour oscillation parameters, we give an outlook on the potential of near-term oscillation physics as well as on the long-term program towards possible future precision oscillation facilities. We discuss accelerator-driven long-baseline experiments as well as nonaccelerator possibilities from atmospheric and reactor neutrinos.


2017 ◽  
Vol 32 (06) ◽  
pp. 1750034 ◽  
Author(s):  
Monojit Ghosh ◽  
Srubabati Goswami ◽  
Sushant K. Raut

The T2K experiment has provided the first hint for the best-fit value for the leptonic CP phase [Formula: see text][Formula: see text][Formula: see text][Formula: see text][Formula: see text] from neutrino data. This is now corroborated by the NO[Formula: see text]A neutrino runs. We study the implications for neutrino mass hierarchy and octant of [Formula: see text] in the context of this data assuming that the true value of [Formula: see text] in nature is [Formula: see text]. Based on simple arguments on degeneracies in the probabilities, we show that a clear signal of [Formula: see text] coming from T2K neutrino (antineutrino) data is only possible if the true hierarchy is normal and the true octant is higher (lower). Thus, if the T2K neutrino and antineutrino data are fitted separately and both give the true value of [Formula: see text], this will imply that nature has chosen the true hierarchy to be normal and [Formula: see text]. However, we find that the combined fit of neutrino and antineutrino data will still point to true hierarchy as normal but the octant of [Formula: see text] will remain undetermined. We do our analysis for both, the current projected exposure ([Formula: see text] pot) and planned extended exposure ([Formula: see text] pot). We also present the CP discovery potential of T2K emphasizing on the role of antineutrinos. We find that one of the main contributions of the antineutrino data is to remove the degenerate solutions with the wrong octant. Thus, the antineutrino run plays a more significant role for those hierarchy-octant combinations for which this degeneracy is present. If this degeneracy is absent, then only neutrino run gives a better result for fixed [Formula: see text]. However, if we marginalize over [Formula: see text] then, sensitivity corresponding to mixed run can be better than pure neutrino run.


2008 ◽  
Vol 23 (21) ◽  
pp. 3388-3394
Author(s):  
HISAKAZU MINAKATA

I discuss why and how powerful is the two-detector setting in neutrino oscillation experiments. I cover three concrete examples: (1) reactor θ13 experiments, (2) T2KK, Tokai-to-Kamioka-Korea two-detector complex for measuring CP violation, determining the neutrino mass hierarchy, and resolving the eight-fold parameter degeneracy, (3) two-detector setting in a neutrino factory at baselines 3000 km and 7000 km for detecting effects of non-standard interactions (NSI) of neutrinos.


Universe ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 41
Author(s):  
Antonio Palazzo

Several anomalies observed in short-baseline neutrino experiments suggest the existence of new light sterile neutrino species. In this review, we describe the potential role of long-baseline experiments in the searches of sterile neutrino properties and, in particular, the new CP-violation phases that appear in the enlarged 3 + 1 scheme. We also assess the impact of light sterile states on the discovery potential of long-baseline experiments of important targets such as the standard 3-flavor CP violation, the neutrino mass hierarchy, and the octant of θ 23 .


2015 ◽  
Vol 30 (07) ◽  
pp. 1550017 ◽  
Author(s):  
Debajyoti Dutta ◽  
Kalpana Bora

In this work, we have explored the possibilities of improving CP violation (CPV) discovery potential of newly planned Long-Baseline Neutrino Experiment (LBNE), USA, by combining with data from reactors. The third mixing angle θ13 is now very precisely measured and this precise measurement of θ13 helps in the measurement of CPV. Here, CPV is studied with and without data from reactors. The impact of placing a neutrino data (ND) is also studied. It is found that CPV discovery potential of LBNE with ND increases when combined with data from reactors. With a far detector of 35 kt, it is possible to obtain 5σ sensitivity of CPV when run for 5 years in ν and 5 years in [Formula: see text] mode. When normal hierarchy is assumed, CPV sensitivity is maximum. CPV discovery is possible by combining 5 years neutrino data from LBNE with 3 years anti-neutrino data from reactors. This study reveals that CPV can also be discovered at 5σ cl in inverted mass hierarchy (IH) mode when appearance measurement of LBNE is combined with reactors.


2014 ◽  
Vol 29 (18) ◽  
pp. 1450095 ◽  
Author(s):  
P. F. Harrison ◽  
R. Krishnan ◽  
W. G. Scott

We present a model of neutrino mixing based on the flavor group Δ(27) in order to account for the observation of a nonzero reactor mixing angle (θ13). The model provides a common flavor structure for the charged-lepton and the neutrino sectors, giving their mass matrices a "circulant-plus-diagonal" form. Mass matrices of this form readily lead to mixing patterns with realistic deviations from tribimaximal mixing, including nonzero θ13. With the parameters constrained by existing measurements, our model predicts an inverted neutrino mass hierarchy. We obtain two distinct sets of solutions in which the atmospheric mixing angle lies in the first and the second octants. The first (second) octant solution predicts the lightest neutrino mass, m3~29 meV (m3~65 meV ) and the CP phase, [Formula: see text], offering the possibility of large observable CP violating effects in future experiments.


2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Gayatri Ghosh

Leptonic CP violating phase δ CP in the light neutrino sector and leptogenesis via present matter-antimatter asymmetry of the Universe entails each other. Probing CP violation in light neutrino oscillation is one of the challenging tasks today. The reactor mixing angle θ 13 measured in reactor experiments, LBL, and DUNE with high precision in neutrino experiments indicates towards the vast dimensions of scope to detect δ CP . The correlation between leptonic Dirac CPV phase δ CP , reactor mixing angle θ 13 , lightest neutrino mass m 1 , and matter-antimatter asymmetry of the Universe within the framework of μ − τ symmetry breaking assuming the type I seesaw dominance is extensively studied here. Here, a SO(10) GUT model with flavor μ − τ symmetry is considered. In this work, the idea is to link baryogenesis through leptogenesis and the hint of CP violation in the neutrino oscillation data to a breaking of the mu-tau symmetry. Small tiny breaking of the μ − τ symmetry allows a large Dirac CP violating phase in neutrino oscillation which in turn is characterized by awareness of measured value of θ 13 and to provide a hint towards a better understanding of the experimentally observed near-maximal value of ν μ − ν τ mixing angle θ 23 ≃ π / 4 . Precise breaking of the μ − τ symmetry is achieved by adding a 120-plet Higgs to the 10 + 1 2 ¯ 6 -dimensional representation of Higgs. The estimated three-dimensional density parameter space of the lightest neutrino mass m 1 , δ CP , and reactor mixing angle θ 13 is constrained here for the requirement of producing the observed value of baryon asymmetry of the Universe through the mechanism of leptogenesis. Carrying out numerical analysis, the allowed parameter space of m 1 , δ CP , and θ 13 is found out which can produce the observed baryon to photon density ratio of the Universe.


2014 ◽  
Vol 2014 ◽  
pp. 1-29 ◽  
Author(s):  
Sanjib Kumar Agarwalla

The discovery of neutrino mixing and oscillations over the past decade provides firm evidence for new physics beyond the Standard Model. Recently,θ13has been determined to be moderately large, quite close to its previous upper bound. This represents a significant milestone in establishing the three-flavor oscillation picture of neutrinos. It has opened up exciting prospects for current and future long-baseline neutrino oscillation experiments towards addressing the remaining fundamental questions, in particular the type of the neutrino mass hierarchy and the possible presence of a CP-violating phase. Another recent and crucial development is the indication of non-maximal 2-3 mixing angle, causing the octant ambiguity ofθ23. In this paper, I will review the phenomenology of long-baseline neutrino oscillations with a special emphasis on sub-leading three-flavor effects, which will play a crucial role in resolving these unknowns. First, I will give a brief description of neutrino oscillation phenomenon. Then, I will discuss our present global understanding of the neutrino mass-mixing parameters and will identify the major unknowns in this sector. After that, I will present the physics reach of current generation long-baseline experiments. Finally, I will conclude with a discussion on the physics capabilities of accelerator-driven possible future long-baseline precision oscillation facilities.


2007 ◽  
Vol 16 (05) ◽  
pp. 1313-1329
Author(s):  
HISAKAZU MINAKATA

I discuss some aspects of future prospects of the experimental exploration of the unknowns in the neutrino mass pattern and the lepton flavor mixing. I start from measuring θ13 by reactors and accelerators as a prerequisite for proceeding to search for leptonic CP violation. I then discuss how CP violation can be uncovered, and how the neutrino mass hierarchy can be determined. I do these by resolving so called the "parameter degeneracy" which is required anyway if one wants to seek precision measurement of the lepton mixing parameters. As a concrete setting for resolving the degeneracy I use the Tokai-to-Kamioka-Korea two detector complex which receives neutrino superbeam from J-PARC, which is sometimes called as "T2KK". It is shown that T2KK is able to resolve all the eight-fold parameter degeneracy in a wide range of the lepton mixing parameters. Some alternative ways of measuring the unknowns are also briefly mentioned.


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