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Understanding the degeneracies in NOvA data

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Autor(es):
Bharti, Suman ; Prakash, Suprabh ; Rahaman, Ushak ; Sankar, S. Uma
Número total de Autores: 4
Tipo de documento: Artigo Científico
Fonte: Journal of High Energy Physics; v. N/A, n. 9, p. 17-pg., 2018-09-07.
Resumo

The combined analysis of v(mu) disappearance and v(e) appearance data of NOvA experiment leads to three nearly degenerate solutions. This degeneracy can be understood in terms of deviations in ve appearance signal, caused by unknown effects, with respect to the signal expected for a reference set of oscillations parameters. We define the reference set to be vacuum oscillations in the limit of maximal 023 and no CP-violation. We then calculate the deviations induced in the ve appearance signal event rate by three unknown effects: (a) matter effects, due to normal or inverted hierarchy (b) octant effects, due to 023 being in higher or lower octant and (c) CP-violation, whether delta(CP) 77/2 or (delta(CP) similar to pi/2. We find that the deviation caused by each of these effects is the same for NOvA. The observed number of ve events in NOvA is equivalent to the increase caused by one of the effects. Therefore, the observed number of ve appearance events of NOvA is the net result of the increase caused by two of the unknown effects and the decrease caused by the third. Thus we get the three degenerate solutions. We also find that further data by NOvA can not distinguish between these degenerate solutions but addition of one year of neutrino run of DUNE can make a distinction between all three solutions. The distinction between the two NH solutions and the IH solution becomes possible because of the larger matter effect in DUNE. The distinction between the two NH solutions with different octants is a result of the synergy between the anti-neutrino data of NOvA and the neutrino data of DUNE. (AU)

Processo FAPESP: 14/19164-6 - Desafios para o século XXI em física e astrofísica de neutrinos
Beneficiário:Orlando Luis Goulart Peres
Modalidade de apoio: Auxílio à Pesquisa - Projetos Especiais
Processo FAPESP: 17/02361-1 - À procura de nova física em experimentos de neutrinos
Beneficiário:Suprabh Prakash
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado