Search results for "neutrinoless double beta"
showing 10 items of 30 documents
Nuclear matrix elements for0νββdecays with light or heavy Majorana-neutrino exchange
2015
We compute the nuclear matrix elements (NMEs) corresponding to the neutrinoless double beta ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) decays of nuclei which attract current experimental interest. We concentrate on ground-state-to-ground-state decay transitions mediated by light (l-NMEs) or heavy (h-NMEs) Majorana neutrinos. The computations are done in realistic single-particle model spaces using the proton-neutron quasiparticle random-phase approximation (pnQRPA) with two-nucleon interactions based on the Bonn one-boson-exchange $G$ matrix. Both the l-NMEs and the h-NMEs include the appropriate short-range correlations, nucleon form factors, and higher-order nucleonic weak …
Role of Single-Particle Energies in Microscopic Interacting Boson Model Double Beta Decay Calculations
2021
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.
Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects
2018
The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector. The extraction of the neutrino mass ordering is a data-driven field expected to evolve very rapidly in the next decade. In this review, we both analyze the present status and describe the physics of subsequent prospects. Firstly, the different current available tools to measure the neutrino mass ordering are described. Namely, reactor, long-baseline (accelerator and atmospheric) neutrino beams, laboratory searches for beta and neutrinol…
Comparative analysis of muon-capture and 0νββ-decay matrix elements
2020
Average matrix elements of ordinary muon capture (OMC) to the intermediate nuclei of neutrinoless double beta (0νββ) decays of current experimental interest are computed and compared with the corresponding energy and multipole decompositions of 0νββ-decay nuclear matrix elements (NMEs). The present OMC computations are performed using the Morita-Fujii formalism by extending the original formalism beyond the leading order. The 0νββ NMEs include the appropriate short-range correlations, nuclear form factors, and higher-order nucleonic weak currents. The nuclear wave functions are obtained in extended no-core single-particle model spaces using the spherical version of the proton-neutron quasip…
Analysis of light neutrino exchange and short-range mechanisms in 0νββ decay
2020
Neutrinoless double beta decay (0νββ) is a crucial test for lepton number violation. Observation of this process would have fundamental implications for neutrino physics, theories beyond the Standard Model and cosmology. Focusing on so-called short-range operators of 0νββ and their potential interplay with the standard light Majorana neutrino exchange, we present the first complete calculation of the relevant nuclear matrix elements, performed within the interacting boson model (IBM-2). Furthermore, we calculate the relevant phase space factors using exact Dirac electron wave functions, taking into account the finite nuclear size and screening by the electron cloud. The obtained numerical r…
Exotic properties of neutrinos using effective Lagrangians and specific models
2013
289 páginas. Tesis Doctoral del Departamento de Física Teórica, de la Universidad de Valencia, y del Instituto de Física Corpuscular (IFIC).
Event reconstruction in NEXT using a ML-EM algorithm
2017
La desintegración doble beta sin neutrinos es un proceso hipotético en el que dos neutrones de un núcleo se transforman en dos protones emitiendo únicamente dos electrones, sin neutrinos. La detección de un proceso así demostraría que los neutrinos son partículas de Majorana y que el número leptónico total no se conserva (las oscilaciones de neutrinos ya han demostrado que el número leptónico por familia no se conserva). La determinación de la naturaleza del neutrino podría responder a varias preguntas de diversa índole dentro de la física de partículas. Primero, podría dar explicación a la escala de masas del neutrino a través de un mecanismo de balancín (see-saw). Por…
The NEXT experiment for neutrinoless double beta decay searches
2015
211 páginas. Tesis Doctoral del Departamento de Física Atómica, Molecular y Nuclear, de la Universidad de Valencia y del Instituto de Física Corpuscular (IFIC).
Muon-capture strength functions in intermediate nuclei of 0νββ decays
2019
Capture rates of ordinary muon capture (OMC) to the intermediate nuclei of neutrinoless double beta (0νββ) decays of current experimental interest are computed. The corresponding OMC (capture-rate) strength functions have been analyzed in terms of multipole decompositions. The computed low-energy OMC-rate distribution to 76 As is compared with the available data of Zinatulina et al. [Phys. Rev. C 99, 024327 (2019)]. The present OMC computations are performed using the Morita-Fujii formalism by extending the original formalism beyond the leading order. The participant nuclear wave functions are obtained in extended no-core single-particle model spaces using the spherical version of proton-ne…