Self-energy operator of a massive neutrino in an external magnetic field
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, PARTICLES, FIELDS, GRAVITATION, AND ASTROPHYSICS
SelfEnergy Operator of a Massive Neutrino in an External Magnetic Field A. A. Dobrynina and N. V. Mikheev Demidov State University, Yaroslavl, 150000 Russia email: [email protected]; [email protected] Received January 22, 2013
Abstract—The effect of the magnetic field on the properties of a massive neutrino is analyzed. A general expression is derived in terms of the selfenergy operator of the neutrino in an external magnetic field of arbi trary strength. This expression is valid for any relationship between the masses of the neutrino, a charged lep ton, and a Wboson. An anomalous magnetic moment of a standard neutrino is investigated. The probability of massive neutrino decay into a Wboson and a charged lepton is calculated for various values of the magnetic field strength. DOI: 10.1134/S1063776114010245
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1. INTRODUCTION
ⱗ (0.3–1.3) eV with a 95% confidence level [10]. All these measurements indicate that the masses of all three light neutrinos are much smaller than the mass of any charged lepton ᐉ = e, μ, τ or quark q = u, d, s, c, b, t. j
The properties of neutrinos have attracted the attention of the researchers worldwide for almost a century. Rapid development and perfection of physi cal experiments have made it possible to detect neutri nos of natural origin [1–3] (atmospheric, solar, space, and geoneutrinos) as well neutrinos produced in nuclear reactors and particlesacceleration experi ments [4]. In addition to the wellknown result obtained on the Large Electron–Positron Collider (LEP) from analysis of “invisible” decays of Zbosons, which indicates that the number of flavors of light neu trinos is Nν = 2.984 ± 0.008 [5] (i.e., less than three), the data on neutrino oscillations reveal that at least two types of neutrinos have a nonzero mass and that mix ing takes place in the lepton sector of the standard model. Analysis of the available experimental data on neutrinos shows that the relations [6] 2
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Neutrinos play a special role in astrophysics. Gamow and Schoenberg noted way back in 1941 [11] that cooling of young neutron stars over approximately the first 100000 years occurs exclusively due to emis sion of neutrinos from the central part. Another (more powerful but relatively shortlived) source of neutrino radiation is the explosion of a supernova with a col lapse in its central part. It was shown [12] that the explosion of a supernova cannot be explained without taking into account the effects of rotation and the presence of a magnetic field. This supernova explosion model was called the magnetorotational model. In this model, a strong magnetic field B ~ 1016 G is formed in the supernova envelope due to magnetorotational instability; it is natural to assume that a strong mag netic field with a slightly lower induction is generated in the supernova remnant as well. The recent discover ies of objects like soft gammaray repeaters (SGRs) and anomalous Xray pulsars (AXPs), for which a strong m
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