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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Angular distributions in electroweak pion production off nucleons: Odd parity hadron terms, strong relative phases, and model dependence

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Autor(es):
Sobczyk, J. E. [1] ; Hernandez, E. [2, 3] ; Nakamura, S. X. [4] ; Nieves, J. [1] ; Sato, T. [5]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Valencia, Ctr Mixto CSIC, Inst Fis Corpuscular IFIC, Inst Invest Paterna, Apartado 22085, E-46071 Valencia - Spain
[2] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca - Spain
[3] Univ Salamanca, IUFFyM, E-37008 Salamanca - Spain
[4] Univ Cruzeiro Sul, LFTC, BR-01506000 Sao Paulo, SP - Brazil
[5] Osaka Univ, RCNP, Ibaraki, Osaka 5670047 - Japan
Número total de Afiliações: 5
Tipo de documento: Artigo Científico
Fonte: Physical Review D; v. 98, n. 7 OCT 5 2018.
Citações Web of Science: 7
Resumo

The study of pion production in nuclei is important for signal and background determinations in current and future neutrino oscillation experiments. The first step, however, is to understand the pion production reactions at the free nucleon level. We present an exhaustive study of the charged-current and neutral-current neutrino and antineutrino pion production off nucleons, paying special attention to the angular distributions of the outgoing pion. We show, using general arguments, that parity violation and time-reversal odd correlations in the weak differential cross sections are generated from the interference between different contributions to the hadronic current that are not relatively real. Next, we present a detailed comparison of three state-of-the-art, microscopic models for electroweak pion production off nucleons, and we also confront their predictions with polarized electron data, as a test of the vector content of these models. We also illustrate the importance of carrying out a comprehensive test at the level of outgoing pion angular distributions, going beyond comparisons done for partially integrated cross sections, where model differences cancel to a certain extent. Finally, we observe that all charged and neutral current distributions show sizable anisotropies, and identify channels for which parity-violating effects are clearly visible. Based on the above results, we conclude that the use of isotropic distributions for the pions in the center of mass of the final pion-nucleon system, as assumed by some of the Monte Carlo event generators, needs to be improved by incorporating the findings of microscopic calculations. (AU)

Processo FAPESP: 16/15618-8 - Análise de Tau e pesados méson hadrônicas decaimentos e neutrino-núcleo interações, para estruturas e interações hadron, e física além do modelo padrão
Beneficiário:Kazuo Tsushima
Linha de fomento: Auxílio à Pesquisa - Pesquisador Visitante - Internacional