Improved description of the 2νββ-decay and a possibility to determine the effective axial-vector coupling constant

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21670%2F18%3A00329996" target="_blank" >RIV/68407700:21670/18:00329996 - isvavai.cz</a>

Výsledek na webu

<a href="http://journals.aps.org/prc/abstract/10.1103/PhysRevC.97.034315" target="_blank" >http://journals.aps.org/prc/abstract/10.1103/PhysRevC.97.034315</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevC.97.034315" target="_blank" >10.1103/PhysRevC.97.034315</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Improved description of the 2νββ-decay and a possibility to determine the effective axial-vector coupling constant

Popis výsledku v původním jazyce

An improved formalism of the two-neutrino double-beta decay (2νββ-decay) rate is presented, which takes into account the dependence of energy denominators on lepton energies via the Taylor expansion. Until now, only the leading term in this expansion has been considered. The revised 2νββ-decay rate and differential characteristics depend on additional phase-space factors weighted by the ratios of 2νββ-decay nuclear matrix elements with different powers of the energy denominator. For nuclei of experimental interest all phase-space factors are calculated by using exact Dirac wave functions with finite nuclear size and electron screening. For isotopes with measured 2νββ-decay half-life the involved nuclear matrix elements are determined within the quasiparticle random-phase approximation with partial isospin restoration. The importance of correction terms to the 2νββ-decay rate due to Taylor expansion is established and the modification of shape of single and summed electron energy distributions is discussed. It is found that the improved calculation of the 2νββ-decay predicts slightly suppressed 2νββ-decay background to the neutrinoless double-beta decay signal. Furthermore, an approach to determine the value of effective weak-coupling constant in nuclear medium g_A^eff is proposed.

Název v anglickém jazyce

Improved description of the 2νββ-decay and a possibility to determine the effective axial-vector coupling constant

Popis výsledku anglicky

An improved formalism of the two-neutrino double-beta decay (2νββ-decay) rate is presented, which takes into account the dependence of energy denominators on lepton energies via the Taylor expansion. Until now, only the leading term in this expansion has been considered. The revised 2νββ-decay rate and differential characteristics depend on additional phase-space factors weighted by the ratios of 2νββ-decay nuclear matrix elements with different powers of the energy denominator. For nuclei of experimental interest all phase-space factors are calculated by using exact Dirac wave functions with finite nuclear size and electron screening. For isotopes with measured 2νββ-decay half-life the involved nuclear matrix elements are determined within the quasiparticle random-phase approximation with partial isospin restoration. The importance of correction terms to the 2νββ-decay rate due to Taylor expansion is established and the modification of shape of single and summed electron energy distributions is discussed. It is found that the improved calculation of the 2νββ-decay predicts slightly suppressed 2νββ-decay background to the neutrinoless double-beta decay signal. Furthermore, an approach to determine the value of effective weak-coupling constant in nuclear medium g_A^eff is proposed.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10304 - Nuclear physics

Projekt

<a href="/cs/project/EF16_013%2F0001733" target="_blank" >EF16_013/0001733: Podzemní laboratoř LSM - česká účast ve výzkumné infrastruktuře evropského významu</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

PHYSICAL REVIEW C

ISSN

2469-9985

e-ISSN

2469-9993

Svazek periodika

97

Číslo periodika v rámci svazku

3

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

11

Strana od-do

—

Kód UT WoS článku

000427314100002

EID výsledku v databázi Scopus

2-s2.0-85044154004