Weak decays of magnetized charged pions in the symmetric gauge

We consider the decay π-→lνl (l=e-,μ-) in the presence of an arbitrary large uniform magnetic field, using the symmetric gauge. The consequences of the axial symmetry of the problem and the issue of angular momentum conservation are discussed in detail. In particular, we analyze the projection of bo...

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Detalles Bibliográficos
Autores: Coppola, Máximo, Gomez Dumm, Daniel Alberto, Noguera, Santiago, Scoccola, Norberto Nerio
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2020
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/168280
Acceso en línea:http://hdl.handle.net/11336/168280
Access Level:acceso abierto
Palabra clave:Hadronic decays
Leptonic, semileptonic & radiative decays
Nonperturbative effects in field theory
https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
Descripción
Sumario:We consider the decay π-→lνl (l=e-,μ-) in the presence of an arbitrary large uniform magnetic field, using the symmetric gauge. The consequences of the axial symmetry of the problem and the issue of angular momentum conservation are discussed in detail. In particular, we analyze the projection of both the canonical and the mechanical total angular momenta along the direction of the magnetic field. It is found that while the former is conserved in the symmetric gauge, the latter is not conserved in both the symmetric and Landau gauges. We derive an expression for the integrated π-→lνl width that coincides exactly with the one we previously found using the Landau gauge, providing an explicit test of the gauge independence of that result. Such an expression implies that for nonzero magnetic fields the decay width does not vanish in the limit in which the outgoing charged leptons can be considered as massless, i.e., it does not exhibit the helicity suppression found in the case of no external field.