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21 pages, 2748 KiB

Open AccessArticle

Angular Distributions of Emitted Electrons in the Two-Neutrino ββ Decay

by Ovidiu Niţescu, Rastislav Dvornický, Sabin Stoica and Fedor Šimkovic

Universe 2021, 7(5), 147; https://doi.org/10.3390/universe7050147 - 14 May 2021

Cited by 8 | Viewed by 2545

Abstract

The two-neutrino double-beta decay (

2 ν β β

-decay) process is attracting more and more attention of the physics community due to its potential to explain nuclear structure aspects of involved atomic nuclei and to constrain new (beyond the Standard model) physics [...] Read more.

The two-neutrino double-beta decay (

2 ν β β

-decay) process is attracting more and more attention of the physics community due to its potential to explain nuclear structure aspects of involved atomic nuclei and to constrain new (beyond the Standard model) physics scenarios. Topics of interest are energy and angular distributions of the emitted electrons, which might allow the deduction of valuable information about fundamental properties and interactions of neutrinos once a new generation of the double-beta decay experiments will be realized. These tasks require an improved theoretical description of the

2 ν β β

-decay differential decay rates, which is presented. The dependence of the denominators in nuclear matrix elements on lepton energies is taken into account via the Taylor expansion. Both the Fermi and Gamow-Teller matrix elements are considered. For nuclei of experimental interest, relevant phase-space factors are calculated by using exact Dirac wave functions with finite nuclear size and electron screening. The uncertainty of the angular correlation factor on nuclear structure parameters is discussed. It is emphasized that the effective axial-vector coupling constant

g_{A}^{eff}

can be determined more reliably by accurately measuring the angular correlation factor. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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15 pages, 492 KiB

Open AccessArticle

The SuSA Model for Neutrino Oscillation Experiments: From Quasielastic Scattering to the Resonance Region

by Maria B. Barbaro, Arturo De Pace and Luisa Fiume

Universe 2021, 7(5), 140; https://doi.org/10.3390/universe7050140 - 10 May 2021

Cited by 10 | Viewed by 1904

Abstract

High-precision studies of Beyond-Standard-Model physics through accelerator-based neutrino oscillation experiments require a very accurate description of neutrino–nucleus cross-sections in a broad energy region, going from quasielastic scattering up to deep, inelastic scattering. In this work, we focus on the following processes: quasielastic scattering, [...] Read more.

High-precision studies of Beyond-Standard-Model physics through accelerator-based neutrino oscillation experiments require a very accurate description of neutrino–nucleus cross-sections in a broad energy region, going from quasielastic scattering up to deep, inelastic scattering. In this work, we focus on the following processes: quasielastic scattering, two-particle-two-hole excitations, and the excitation of the first (Delta) and second (Roper) resonances of the nucleon. The nuclear model is fully relativistic and includes both one- and two-body currents. We compare our results with recent T2K and MicroBooNE data on carbon and argon targets, and present predictions for DUNE kinematics. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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19 pages, 507 KiB

Open AccessArticle

Nuclear Matrix Elements for Heavy Ion Sequential Double Charge Exchange Reactions

by Horst Lenske, Jessica Bellone, Maria Colonna and Danilo Gambacurta

Universe 2021, 7(4), 98; https://doi.org/10.3390/universe7040098 - 13 Apr 2021

Cited by 24 | Viewed by 1851

Abstract

The theoretical approach to a sequential heavy ion double charge exchange reaction is presented. A brief introduction into the formal theory of second-order nuclear reactions and their application to Double Single Charge Exchange (DSCE) reactions by distorted wave theory is given, thereby completing [...] Read more.

The theoretical approach to a sequential heavy ion double charge exchange reaction is presented. A brief introduction into the formal theory of second-order nuclear reactions and their application to Double Single Charge Exchange (DSCE) reactions by distorted wave theory is given, thereby completing the theoretical background to our recent work. Formally, the DSCE reaction amplitudes are shown to be separable into superpositions of distortion factors, accounting for initial and final state ion–ion interactions, and nuclear matrix elements. A broad space is given to the construction of nuclear DSCE response functions on the basis of polarization propagator theory. The nuclear response tensors resemble the nuclear matrix elements of 2νββ decay in structure but contain in general a considerable more complex multipole and spin structure. The QRPA theory is used to derive explicit expressions for nuclear matrix elements (NMEs). The differences between the NME of the first and the second interaction vertexes in a DSCE reaction is elucidated. Reduction schemes for the transition form factors are discussed by investigating the closure approximation and the momentum structure of form factors. DSCE unit strength cross sections are derived. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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15 pages, 4420 KiB

Open AccessArticle

The NUMEN Project: Toward New Experiments with High-Intensity Beams

by Clementina Agodi, Antonio D. Russo, Luciano Calabretta, Grazia D’Agostino, Francesco Cappuzzello, Manuela Cavallaro, Diana Carbone, Paolo Finocchiaro, Luciano Pandola, Domenico Torresi, Daniela Calvo, Diego Sartirana, Luigi Campajola, Vittoria Capirossi, Felice Iazzi and Federico Pinna

Universe 2021, 7(3), 72; https://doi.org/10.3390/universe7030072 - 22 Mar 2021

Cited by 25 | Viewed by 2730

Abstract

The search for neutrinoless double-beta (0νββ) decay is currently a key topic in physics, due to its possible wide implications for nuclear physics, particle physics, and cosmology. The NUMEN project aims to provide experimental information on the nuclear matrix elements (NMEs) that are [...] Read more.

The search for neutrinoless double-beta (0νββ) decay is currently a key topic in physics, due to its possible wide implications for nuclear physics, particle physics, and cosmology. The NUMEN project aims to provide experimental information on the nuclear matrix elements (NMEs) that are involved in the expression of 0νββ decay half-life by measuring the cross section of nuclear double-charge exchange (DCE) reactions. NUMEN has already demonstrated the feasibility of measuring these tiny cross sections for some nuclei of interest for the 0νββ using the superconducting cyclotron (CS) and the MAGNEX spectrometer at the Laboratori Nazionali del Sud (LNS.) Catania, Italy. However, since the DCE cross sections are very small and need to be measured with high sensitivity, the systematic exploration of all nuclei of interest requires major upgrade of the facility. R&D for technological tools has been completed. The realization of new radiation-tolerant detectors capable of sustaining high rates while preserving the requested resolution and sensitivity is underway, as well as the upgrade of the CS to deliver beams of higher intensity. Strategies to carry out DCE cross-section measurements with high-intensity beams were developed in order to achieve the challenging sensitivity requested to provide experimental constraints to 0νββ NMEs. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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11 pages, 316 KiB

Open AccessArticle

Role of Single-Particle Energies in Microscopic Interacting Boson Model Double Beta Decay Calculations

by Jenni Kotila

Universe 2021, 7(3), 66; https://doi.org/10.3390/universe7030066 - 11 Mar 2021

Viewed by 2442

Abstract

Single-particle level energies form a significant input in nuclear physics calculations where single-particle degrees of freedom are taken into account, including microscopic interacting boson model investigations. The single-particle energies may be treated as input parameters that are fitted to reach an optimal fit [...] Read more.

Single-particle level energies form a significant input in nuclear physics calculations where single-particle degrees of freedom are taken into account, including microscopic interacting boson model investigations. The single-particle energies may be treated as input parameters that are fitted to reach an optimal fit to the data. Alternatively, they can be calculated using a mean field potential, or they can be extracted from available experimental data, as is done in the current study. The role of single-particle level energies in the microscopic interacting boson model calculations is discussed with special emphasis on recent double beta decay calculations. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

16 pages, 512 KiB

Open AccessArticle

Initial State Interaction for the ²⁰Ne + ¹³⁰Te and ¹⁸O + ¹¹⁶Sn Systems at 15.3 AMeV from Elastic and Inelastic Scattering Measurements

by Diana Carbone, Roberto Linares, Paulina Amador-Valenzuela, Salvatore Calabrese, Francesco Cappuzzello, Manuela Cavallaro, Suna Firat, Maria Fisichella, Alessandro Spatafora, Luis Acosta, Clementina Agodi, Ismail Boztosun, Giuseppe A. Brischetto, Daniela Calvo, Efrain R. Chávez Lomelí, Irene Ciraldo, Mauro Cutuli, Franck Delaunay, Nikit Deshmukh, Paolo Finocchiaro, Antonino Foti, Aylin Hacisalihoglu, Felice Iazzi, Laura La Fauci, Gaetano Lanzalone, Nilberto H. Medina, Djalma Mendes, José R. B. Oliveira, Athina Pakou, Luciano Pandola, Horia Petrascu, Federico Pinna, Giuseppe Russo, Onoufrios Sgouros, Selçuk O. Solakci, Vasilis Soukeras, George Souliotis, Domenico Torresi, Salvatore Tudisco, Aydin Yildirim and Vinicius A. B. Zagatto Show full author list Hide full author list

Universe 2021, 7(3), 58; https://doi.org/10.3390/universe7030058 - 5 Mar 2021

Cited by 32 | Viewed by 3058

Abstract

Double charge exchange (DCE) reactions could provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-

β

decay. To achieve this goal, a detailed description of the reaction mechanism is mandatory. This requires the full characterization of [...] Read more.

Double charge exchange (DCE) reactions could provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-

β

decay. To achieve this goal, a detailed description of the reaction mechanism is mandatory. This requires the full characterization of the initial and final-state interactions, which are poorly known for many of the projectile-target systems involved in future DCE studies. Among these, we intend to study the

^{20}

Ne +

^{130}

Te and

^{18}

O +

^{116}

Sn systems at 15.3 AMeV, which are particularly relevant due to their connection with the

^{130}

Te

\to^{130}

Xe and

^{116}

Cd

\to^{116}

Sn double-

β

decays. We measure the elastic and inelastic scattering cross-section angular distributions and compare them with theoretical calculations performed in the optical model, one-step distorted wave Born approximation, and coupled-channel approaches using the São Paulo double-folding optical potential. A good description of the experimental data in the whole explored range of transferred momenta is obtained provided that couplings with the 2

_{1}^{+}

states of the projectile and target are explicitly included within the coupled-channel approach. These results are relevant also in the analysis of other quasi-elastic reaction channels in these systems, in which the same couplings should be included. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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12 pages, 877 KiB

Open AccessArticle

Sensitivity of a Liquid Xenon Detector to Neutrino–Nucleus Coherent Scattering and Neutrino Magnetic Moment from Reactor Neutrinos

by Kaixuan Ni, Jianyang Qi, Evan Shockley and Yuehuan Wei

Universe 2021, 7(3), 54; https://doi.org/10.3390/universe7030054 - 3 Mar 2021

Cited by 8 | Viewed by 2541

Abstract

Liquid xenon is one of the leading targets to search for dark matter via its elastic scattering on nuclei or electrons. Due to their low-threshold and low-background capabilities, liquid xenon detectors can also detect coherent elastic neutrino–nucleus scattering (CE

ν

NS) or neutrino–electron [...] Read more.

Liquid xenon is one of the leading targets to search for dark matter via its elastic scattering on nuclei or electrons. Due to their low-threshold and low-background capabilities, liquid xenon detectors can also detect coherent elastic neutrino–nucleus scattering (CE

ν

NS) or neutrino–electron scattering. In this paper, we investigate the feasibility of a compact and movable liquid xenon detector with an active target mass of O(10∼100) kg and single-electron sensitivity to detect CE

ν

NS from anti-neutrinos from a nuclear reactor. Assuming a single- and few-electron background rate at the level achieved by the XENON10/100 experiments, we expect a 5-

σ

detection of CE

ν

NS with less than 400 kg-days of exposure. We further investigate the sensitivity of such a detector to neutrino magnetic moment with neutrino electron scattering. If an electronic recoil background rate of 0.01∼0.1 events/keV/kg/day above 1 keV can be achieved with adequate shielding, a liquid xenon detector can reach a neutrino magnetic moment sensitivity of

10^{- 11} μ_{B}

, which would improve upon the current most-constraining laboratory limits from the GEMMA and Borexino experiments. Additionally, such a detector would be able to probe the region compatible with a magnetic moment interpretation of the low-energy excess electronic recoil events recently reported by XENON1T. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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29 pages, 6542 KiB

Open AccessArticle

Double Beta Decay to Excited States of Daughter Nuclei

by Pierluigi Belli, Rita Bernabei, Fabio Cappella, Vincenzo Caracciolo, Riccardo Cerulli, Antonella Incicchitti and Vittorio Merlo

Universe 2020, 6(12), 239; https://doi.org/10.3390/universe6120239 - 13 Dec 2020

Cited by 18 | Viewed by 3644

Abstract

In this paper we review results obtained in the searches of double beta decays to excited states of the daughter nuclei and illustrate the related experimental techniques. In particular, we describe in some detail the only two cases in which the transition has [...] Read more.

In this paper we review results obtained in the searches of double beta decays to excited states of the daughter nuclei and illustrate the related experimental techniques. In particular, we describe in some detail the only two cases in which the transition has been observed; that is the

2 β^{-} (0^{+} \to 0_{1}^{+})

decay of

^{100}

Mo and

^{150}

Nd nuclides. Moreover, the most significant results in terms of lower limits on the half-life are also summarized. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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17 pages, 1323 KiB

Open AccessArticle

Neutrino-Mass Sensitivity and Nuclear Matrix Element for Neutrinoless Double Beta Decay

by Hiroyasu Ejiri

Universe 2020, 6(12), 225; https://doi.org/10.3390/universe6120225 - 27 Nov 2020

Cited by 19 | Viewed by 2780

Abstract

Neutrinoless double beta decay (DBD) is a useful probe to study neutrino properties such as the Majorana nature, the absolute neutrino mass, the CP phase and the others, which are beyond the standard model. The nuclear matrix element (NME) for DBD is crucial [...] Read more.

Neutrinoless double beta decay (DBD) is a useful probe to study neutrino properties such as the Majorana nature, the absolute neutrino mass, the CP phase and the others, which are beyond the standard model. The nuclear matrix element (NME) for DBD is crucial to extract the neutrino properties from the experimental transition rate. The neutrino-mass sensitivity, i.e., the minimum neutrino-mass to be measured by the DBD experiment, is very sensitive to the DBD NME. Actually, the NME is one of the key elements for designing the DBD experiment. Theoretical evaluation for the DBD NME, however, is very hard. Recently experimental studies of charge-exchange nuclear and leptonic reactions have shown to be used to get single-

β

NMEs associated with the DBD NME. Critical discussions are made on the neutrino-mass sensitivity and the NME for the DBD neutrino-mass study and on the experimental studies of the single-

β

NMEs and nuclear structures associated with DBD NMEs. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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Review

Jump to: Research

22 pages, 539 KiB

Open AccessReview

What Is Matter According to Particle Physics, and Why Try to Observe Its Creation in a Lab?

by Francesco Vissani

Universe 2021, 7(3), 61; https://doi.org/10.3390/universe7030061 - 9 Mar 2021

Cited by 9 | Viewed by 2653

Abstract

The standard model of elementary interactions has long qualified as a theory of matter, in which the postulated conservation laws (one baryonic and three leptonic) acquire theoretical meaning. However, recent observations of lepton number violations—neutrino oscillations—demonstrate its incompleteness. We discuss why these considerations [...] Read more.

The standard model of elementary interactions has long qualified as a theory of matter, in which the postulated conservation laws (one baryonic and three leptonic) acquire theoretical meaning. However, recent observations of lepton number violations—neutrino oscillations—demonstrate its incompleteness. We discuss why these considerations suggest the correctness of Ettore Majorana’s ideas on the nature of neutrino mass and add further interest to the search for an ultra-rare nuclear process in which two particles of matter (electrons) are created, commonly called neutrinoless double beta decay. The approach of the discussion is mainly historical, and its character is introductory. Some technical considerations, which highlight the usefulness of Majorana’s representation of gamma matrices, are presented in the appendix. Full article

(This article belongs to the Special Issue Nuclear Issues for Neutrino Physics)

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