scholarly journals Towards determining the neutrino mass hierarchy: weak lensing and galaxy clustering forecasts with baryons and intrinsic alignments

2020 ◽  
Vol 493 (2) ◽  
pp. 1640-1661 ◽  
Author(s):  
David Copeland ◽  
Andy Taylor ◽  
Alex Hall
Keyword(s):  
Neutrino Mass ◽  
Stage Iv ◽  
Double Beta Decay ◽  
Weak Lensing ◽  
Small Scale ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Galaxy Clustering ◽  
The Impact ◽  
Adiabatic Contraction

ABSTRACT The capacity of Stage IV lensing surveys to measure the neutrino mass sum and differentiate between the normal and inverted mass hierarchies depends on the impact of nuisance parameters describing small-scale baryonic astrophysics and intrinsic alignments. For a Euclid-like survey, we perform the first combined weak lensing and galaxy clustering Fisher analysis with baryons, intrinsic alignments, and massive neutrinos for both hierarchies. We use a matter power spectrum generated from a halo model that captures the impact of baryonic feedback and adiabatic contraction. For weak lensing, we find that baryons cause severe degradation to forecasts of the neutrino mass sum, Σ, approximately doubling σΣ. We show that including galaxy clustering constraints from Euclid and BOSS, and cosmic microwave background (CMB) Planck priors, can reduce this degradation to σΣ to 9 per cent and 16 per cent for the normal and inverted hierarchies, respectively. The combined forecasts, $\sigma _{\Sigma _{\rm {NH}}}=0.034\, \rm {eV}$ and $\sigma _{\Sigma _{\rm {IH}}}=0.034\, \rm {eV}$, preclude a meaningful distinction of the hierarchies but could be improved upon with future CMB priors on ns and information from neutrinoless double beta decay to achieve a 2σ distinction. The effect of intrinsic alignments on forecasts is shown to be minimal, with σΣ even experiencing mild improvements due to information from the intrinsic alignment signal. We find that while adiabatic contraction and intrinsic alignments will require careful calibration to prevent significant biasing of Σ, there is less risk presented by feedback from energetic events like AGN and supernovae.

scholarly journals Current Status and Future Prospects of the SNO+ Experiment

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
S. Andringa ◽  
E. Arushanova ◽  
S. Asahi ◽  
M. Askins ◽  
D. J. Auty ◽  
...  
Keyword(s):  
Phase I ◽  
Neutrino Mass ◽  
Liquid Scintillator ◽  
Solar Neutrinos ◽  
Double Beta Decay ◽  
Current Status ◽  
Pure Liquid ◽  
Neutrino Experiment ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy

SNO+ is a large liquid scintillator-based experiment located 2 km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12 m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0νββ) of130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55–133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The0νββPhase I is foreseen for 2017.

scholarly journals Inverted neutrino mass hierarchy and mixing in the Zee-Babu model

2016 ◽  
Vol 25 (4) ◽  
pp. 291
Author(s):  
Vo Van Vien ◽  
Hoang Ngoc Long ◽  
Phan Ngoc Thu
Keyword(s):  
Cp Violation ◽  
Effective Mass ◽  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Double Beta Decay ◽  
Recent Analysis ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy

We show that the neutrino mass matrix of the Zee-Babu model isable to fit the recent data on neutrino masses and mixingwith non-zero $\theta_{13}$ in the inverted neutrino mass hierarchy. The results show that the Majorana  phases are equal to zero and the Dirac phase ($\de$) ispredicted to either $0$ or $\pi$, i. e, there is no CP violation in the Zee-Babu model at the two loop level. The effective mass governingneutrinoless double beta decay and the sum of neutrino masses areconsistent with the recent analysis.

scholarly journals On resolving the dark LMA solution at neutrino oscillation experiments

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Sandhya Choubey ◽  
Dipyaman Pramanik
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Double Beta Decay ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Mixing Angle ◽  
Long Baseline ◽  
Combine Information ◽  
Oscillation Experiment

Abstract In presence of non standard interactions (NSI), the solar neutrino data is consistent with two solutions, one close to the standard LMA solution with sin2θ12 ≃ 0.31 and another with $$ {\sin}^2{\theta}_{12}^D\simeq 0.69\left(=1-{\sin}^2{\theta}_{12}\right) $$ sin 2 θ 12 D ≃ 0.69 = 1 − sin 2 θ 12 . The latter has been called the Dark LMA (DLMA) solution in the literature and essentially brings an octant degeneracy in the measurement of the mixing angle θ12. This θ12 octant degeneracy is hard to resolve via oscillations because of the existence of the so-called “generalised mass hierarchy degeneracy” of the neutrino mass matrix in presence of NSI. One might think that if the mass hierarchy is independently determined in a non-oscillation experiment such as neutrino-less double beta decay, one might be able to break the θ12 octant degeneracy. In this paper we study this in detail in the context of long-baseline experiments (Pμμ channel) as well as reactor experiments (Pee channel) and show that if we combine information from both long-baseline and reactor experiments we can find the correct octant and hence value of θ12. We elaborate the reasons for it and study the prospects of determining the θ12 octant using T2HK, DUNE and JUNO experiments. Of course, one would need information on the neutrino mass hierarchy as well.

scholarly journals A Phenomenological Model of Effectively Oscillating Massless Neutrinos and Its Implications

2020 ◽  
Vol 240 ◽  
pp. 02002
Author(s):  
Jianlong Lu ◽  
Aik Hui Chan ◽  
Choo Hiap Oh
Keyword(s):  
Neutrino Oscillation ◽  
Neutrino Mass ◽  
Phenomenological Model ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Mass Hierarchy ◽  
Neutrino Mixing ◽  
Open Problems ◽  
Neutrino Mass Hierarchy ◽  
Flavor Changing

We discuss an alternative picture of neutrino oscillation. In this phenomenological model, the flavor-changing phenomena of massless neutrinos arise from scattering processes between neutrinos and four types of undetected spin-0 massive particles pervading throughout the Universe, instead of neutrinos’ own nature. These scattering processes are kinematically similar to Compton scattering. One type of left-handed massless sterile neutrino is needed in order to reproduce the neutrino oscillation modes predicted in the theory of neutrino mixing. Implications of our model include the existence of sterile neu- trinos, the nonconservation of active neutrinos, the possible mismatch among three neutrino mass squared differences ∆m2ij interpreted in the theory of neutrino mixing, the spacetime dependence of neutrino oscillation, and the impossibility of neutrinoless double beta decay. Several important open problems in neutrino physics become trivial or less severe in our model, such as the smallness of neutrino masses, neutrino mass hierarchy, the mechanism responsible for neutrino masses, and the Dirac/Majorana nature of neutrinos.

Majorana phases and neutrino–antineutrino oscillations

2014 ◽  
Vol 29 (21) ◽  
pp. 1444003 ◽  
Author(s):  
Zhi-Zhong Xing
Keyword(s):  
Neutrino Mass ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Special Cases ◽  
The Future ◽  
Massive Neutrinos ◽  
Neutrino Experiments ◽  
Majorana Phases

If massive neutrinos are the Majorana particles, how to pin down the Majorana CP-violating phases will eventually become an unavoidable question relevant to the future neutrino experiments. I argue that a study of neutrino–antineutrino oscillations will greatly help in this regard, although the issue remains purely academic at present. In this talk I first derive the probabilities and CP-violating asymmetries of neutrino–antineutrino oscillations in the three-flavor framework, and then illustrate their properties in two special cases: the normal neutrino mass hierarchy with m1 = 0 and the inverted neutrino mass hierarchy with m3 = 0. I demonstrate the significant contributions of the Majorana phases to the CP-violating asymmetries, even in the absence of the Dirac phase.

A Basic Study on the Neutrino Mass Hierarchy With Reactor Antineutrinos

2014 ◽  
Vol 64 (8) ◽  
pp. 806-810
Author(s):  
Myoung Youl PAC* ◽  
June Ho CHOI
Keyword(s):  
Neutrino Mass ◽  
Mass Hierarchy ◽  
Basic Study ◽  
Neutrino Mass Hierarchy

scholarly journals Supernova 1987A did not test the neutrino mass hierarchy

2002 ◽  
Vol 532 (1-2) ◽  
pp. 19-28 ◽  
Author(s):  
V. Barger ◽  
D. Marfatia ◽  
B.P. Wood
Keyword(s):  
Neutrino Mass ◽  
Mass Hierarchy ◽  
Neutrino Mass Hierarchy ◽  
Supernova 1987A
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