Characterization of cubic Li$$_{2}$$$$^{100}$$MoO$$_4$$ crystals for the CUPID experiment

AbstractThe CUPID Collaboration is designing a tonne-scale, background-free detector to search for double beta decay with sufficient sensitivity to fully explore the parameter space corresponding to the inverted neutrino mass hierarchy scenario. One of the CUPID demonstrators, CUPID-Mo, has proved the potential of enriched Li$$_{2}$$ 2 $$^{100}$$ 100 MoO$$_4$$ 4 crystals as suitable detectors for neutrinoless double beta decay search. In this work, we characterised cubic crystals that, compared to the cylindrical crystals used by CUPID-Mo, are more appealing for the construction of tightly packed arrays. We measured an average energy resolution of ($$6.7\pm 0.6$$ 6.7 ± 0.6 ) keV FWHM in the region of interest, approaching the CUPID target of 5 keV FWHM. We assessed the identification of $$\alpha $$ α particles with and without a reflecting foil that enhances the scintillation light collection efficiency, proving that the baseline design of CUPID already ensures a complete suppression of this $$\alpha $$ α -induced background contribution. We also used the collected data to validate a Monte Carlo simulation modelling the light collection efficiency, which will enable further optimisations of the detector.

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

Communications in Physics ◽

10.15625/0868-3166/25/4/7651 ◽

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.

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GERDA and LEGEND: Probing the Neutrino Nature and Mass at 100 meV and beyond

Universe ◽

10.3390/universe7090314 ◽

2021 ◽

Vol 7 (9) ◽

pp. 314

Author(s):

Carla Maria Cattadori ◽

Francesco Salamida

Keyword(s):

Beta Decay ◽

Neutrino Mass ◽

Phase Ii ◽

Energy Resolution ◽

Average Energy ◽

Double Beta Decay ◽

Mass Hierarchy ◽

Inverted Hierarchy ◽

Sensitivity Experiment ◽

Background Index

The Gerda (GERmanium Detector Array) project, located at Laboratori Nazionali del Gran Sasso (LNGS), was started in 2005, a few years after the claim of evidence for the neutrinoless double beta decay (0νββ) of 76Ge to the ground state of 76Se: it is an ultra-rare process whose detection would directly establish the Majorana nature of the neutrino and provide a measurement of its mass and mass hierarchy. The aim of Gerda was to confirm or disprove the claim by an increased sensitivity experiment. After establishing the new technology of Ge detectors operated bare in liquid Argon and since 2011, Gerda efficiently collected data searching for 0νββ of 76Ge, first deploying the 76Ge-enriched detectors from two former experiments and later new detectors with enhanced signal-to-background rejection, produced from freshly 76Ge-enriched material. Since then, the Gerda setup has been upgraded twice, first in 2013–2015 and later in 2018. The period before 2013 is Phase I and that after 2015 is Phase II. Both the Gerda setup and the analysis tools evolved along the project lifetime, allowing to achieve the remarkable average energy resolution of ∼3.6 and ∼2.6 keV for Coaxial Germanium (Coax) detectors and for Broad Energy Germanium (BEGe), respectively, and the background index of 5.2−1.3+1.6 · 10−4 cts/(keV·kg·yr) in a 230 keV net range centered at Qββ. No evidence of the 0νββ decay at Qββ = 2039.1 keV has been found, hence the limit of 1.8·1026 yr on the half-life (T1/20ν) at 90% C.L. was set with the exposure of 127.2 kg·yr. The corresponding limit range for the effective Majorana neutrino mass mee has been set to 79–180 meV. The Gerda performances in terms of background index, energy resolution and exposure are the best achieved so far by 76Ge double beta decay experiments. In Phase II, Gerda succeeded in operating in a background free regime and set a world record. In 2017, the Legend Collaboration was born from the merging of the Gerda and Majorana Collaborations and resources with the aim to further improve the Gerda sensitivity. First, the Legend200 project, with a mass of up to 200 kg of 76Ge-enriched detectors, aims to further improve the background index down to <0.6 · 10−3 cts/(keV·kg·yr) to explore the Inverted Hierarchy region of the neutrino mass ordering, then the Legend1000 (1 ton of 76Ge-enriched) will probe the Normal Hierarchy. In this paper, we describe the Gerda experiment, its evolution, the data analysis flow, a selection of its results and technological achievements, and finally the design, features and challenges of Legend, the Gerda prosecutor.

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On resolving the dark LMA solution at neutrino oscillation experiments

Journal of High Energy Physics ◽

10.1007/jhep12(2020)133 ◽

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.

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Double-beta decay and its potential to explore beyond standard model physics

International Journal of Modern Physics A ◽

10.1142/s0217751x18450124 ◽

2018 ◽

Vol 33 (34) ◽

pp. 1845012

Author(s):

Sabin Stoica

Keyword(s):

Standard Model ◽

Beta Decay ◽

Axial Vector ◽

Double Beta Decay ◽

Mass Hierarchy ◽

Neutrino Mass Hierarchy ◽

Decay Modes ◽

Precise Calculation ◽

Reliable Computations ◽

Bsm Physics

Double-beta decay (DBD) is a rare nuclear process of great interest due to its potential to provide information about physics beyond the Standard Model (BSM). For example, the discovery of the neutrinoless double-beta [Formula: see text] decay mode could give information about important issues such as possible violations of Lorentz symmetry and lepton number, nature of neutrinos (are they Dirac- or Majorana-like particles?), neutrino absolute masses, neutrino mass hierarchy, existence of heavy (sterile) neutrinos, etc. In the theoretical study of DBD, one needs a precise calculation of the nuclear matrix elements (NMEs) and phase space factors (PSFs) entering the half-lives formulas, for different decay modes, transitions and mechanisms of occurrence. Reliable computations of these quantities may result in reliable predictions of DBD half-lives and constrains of the BSM parameters related to the possible mechanisms that can contribute to the [Formula: see text] decay. In this paper, I briefly review the theoretical challenges in the study of [Formula: see text] decay. I describe the computation of the NMEs and PSFs and present results for a number of selected nuclei. Then, I show the broader potential of this process to provide information about BSM physics and present new upper limits for parameters associated with light neutrino, heavy neutrino and SUSY exchange mechanisms. Finally, I suggest a more consistent approach to calculate the NMEs and PSFs, namely to compute directly their product and discuss some possibilities to reduce the errors related to the uncertain value of the axial-vector constant.

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Searching for Neutrinoless Double-Beta Decay of130Te with CUORE

Advances in High Energy Physics ◽

10.1155/2015/879871 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 78

Author(s):

D. R. Artusa ◽

F. T. Avignone ◽

O. Azzolini ◽

M. Balata ◽

T. I. Banks ◽

...

Keyword(s):

Beta Decay ◽

Energy Resolution ◽

Confidence Level ◽

Half Life ◽

Average Energy ◽

Neutrinoless Double Beta Decay ◽

Lepton Number ◽

Double Beta Decay ◽

Current Status ◽

Upper Limit

Neutrinoless double-beta (0νββ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0νββdecay of130Te using an array of 988 TeO2crystal bolometers operated at 10 mK. The detector will contain 206 kg of130Te and have an average energy resolution of 5 keV; the projected 0νββdecay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1σ(9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

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Current Status and Future Prospects of the SNO+ Experiment

Advances in High Energy Physics ◽

10.1155/2016/6194250 ◽

2016 ◽

Vol 2016 ◽

pp. 1-21 ◽

Cited By ~ 110

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.

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa314 ◽

2020 ◽

Vol 493 (2) ◽

pp. 1640-1661 ◽

Cited By ~ 2

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.

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The NUMEN Heavy Ion Multidetector for a Complementary Approach to the Neutrinoless Double Beta Decay

Universe ◽

10.3390/universe6090129 ◽

2020 ◽

Vol 6 (9) ◽

pp. 129 ◽

Cited By ~ 1

Author(s):

Paolo Finocchiaro ◽

Luis Acosta ◽

Clementina Agodi ◽

Carmen Altana ◽

Paulina Amador-Valenzuela ◽

...

Keyword(s):

Beta Decay ◽

Neutrinoless Double Beta Decay ◽

Heavy Ion ◽

Double Beta Decay ◽

Mass Hierarchy ◽

Reaction Products ◽

Exchange Reactions ◽

Intrinsic Nature ◽

Experimental Apparatus ◽

Double Charge

Neutrinos are so far the most elusive known particles, and in the last decades many sophisticated experiments have been set up in order to clarify several questions about their intrinsic nature, in particular their masses, mass hierarchy, intrinsic nature of Majorana or Dirac particles. Evidence of the Neutrinoless Double-Beta Decay (NDBD) would prove that neutrinos are Majorana particles, thus improving the understanding of the universe itself. Besides the search for several large underground experiments for the direct experimental detection of NDBD, the NUMEN experiment proposes the investigation of a nuclear mechanism strongly linked to this decay: the Double Charge Exchange reactions (DCE). As such reactions share with the NDBD the same initial and final nuclear states, they could shed light on the determination of the Nuclear Matrix Elements (NMEs), which play a relevant role in the decay. The physics of DCE is described elsewhere in this issue, while the focus of this paper will be on the challenging experimental apparatus currently under construction in order to fulfil the requirements of the NUMEN experiment. The overall structure of the technological improvement to the cyclotron, along with the newly developed detection systems required for tracking and identifying the reaction products and their final excitation level are described.

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High Scale Type-II Seesaw, Dominant Double Beta Decay within Cosmological Bound and LFV Decays in SU(‎5)

Advances in High Energy Physics ◽

10.1155/2019/3572862 ◽

2019 ◽

Vol 2019 ◽

pp. 1-19 ◽

Cited By ~ 5

Author(s):

M. K. Parida ◽

Rajesh Satpathy

Keyword(s):

Beta Decay ◽

Neutrino Mass ◽

Double Beta Decay ◽

Type I ◽

Mass Hierarchy ◽

Type Ii ◽

Inverted Hierarchy ◽

Mass Generation ◽

Neutrino Mass Generation ◽

Physical Phenomena

Very recently novel implementation of type-II seesaw mechanism for neutrino mass has been proposed in SU(5) grand unified theory with a number of desirable new physical phenomena beyond the standard model. Introducing heavy right-handed neutrinos and extra fermion singlets, in this work we show how the type-I seesaw cancellation mechanism works in this SU(5) framework. Besides predicting verifiable LFV decays, we further show that the model predicts dominant double beta decay with normal hierarchy or inverted hierarchy of active light neutrino masses in concordance with cosmological bound. In addition a novel right-handed neutrino mass generation mechanism, independent of type-II seesaw predicted mass hierarchy, is suggested in this work.

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Shell Model Studies of Competing Mechanisms to the Neutrinoless Double-Beta Decay in 124Sn, 130Te, and 136Xe

Advances in High Energy Physics ◽

10.1155/2016/1903767 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Andrei Neacsu ◽

Mihai Horoi

Keyword(s):

Beyond Standard Model ◽

Standard Model ◽

Shell Model ◽

Beta Decay ◽

Neutrinoless Double Beta Decay ◽

Mass Scale ◽

Double Beta Decay ◽

Majorana Fermion ◽

Mass Hierarchy ◽

Model Studies

Neutrinoless double-beta decay is a predicted beyond Standard Model process that could clarify some of the not yet known neutrino properties, such as the mass scale, the mass hierarchy, and its nature as a Dirac or Majorana fermion. Should this transition be observed, there are still challenges in understanding the underlying contributing mechanisms. We perform a detailed shell model investigation of several beyond Standard Model mechanisms that consider the existence of right-handed currents. Our analysis presents different venues that can be used to identify the dominant mechanisms for nuclei of experimental interest in the mass A~130 region (124Sn, 130Te, and 136Xe). It requires accurate knowledge of nine nuclear matrix elements that we calculate in addition to the associated energy-dependent phase space factors.

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