相关论文: Dirac Neutrinos and Primordial Magnetic Fields
If massive neutrinos possess magnetic moments, they can undergo spin flip in a magnetic field. The magnetic fields needed for a meaningful measurement of neutrino moments could be very high and may occur in astronomical objects such as some…
The phenomena of neutrino spin flavour precession in the presence of an extraneous magnetic field is a repercussion of neutrino magnetic moment which is consociated with the physics beyond the standard model of electroweak interactions.…
Neutrinos with a magnetic moment $\mu$ change their helicity when interacting with an electromagnetic field. Various aspects of this effect have been described as spin precession, spin-flip scattering, and magnetic Cherenkov radiation.…
Electromagnetic properties of neutrinos, if ever observed, could help to decide the Dirac versus Majorana nature of neutrinos. We show that the magnetic moments of Majorana neutrinos have to fulfill triangle inequalities,…
The equilibration of the right-helicity states $\nu_+$ of light Dirac-neutrinos is discussed. I point out that the $\nu_+$ production rate is enhanced by weak gauge boson pole effects so that the right-helicity component of $\nu_\tau$ is…
Several new and interesting aspects of neutrino oscillations in a magnetic field are considered: 1) We develop a standard usually used approach to the neutrino spin oscillations in the neutrino mass basis and obtain the effective neutrino…
We study oscillations of Dirac neutrinos in background matter and a plane electromagnetic wave. First, we find the new exact solution of the Dirac-Pauli equation for a massive neutrino with the anomalous magnetic moment electroweakly…
The process of the two-step conversion of the neutrino helicity, $\nu_L \to \nu_R \to \nu_L$, is analysed in the supernova conditions, where the first stage is realized due to the interaction of the neutrino magnetic moment with the plasma…
Experimental limits on neutrino magnetic moments remain several orders of magnitude above the predictions of the Standard Model; therefore, any future detection would provide unambiguous evidence for new physics. In models with Dirac…
The main features of the observables in the SNO and Super-Kamiokande solar neutrino experiments in the case of neutrino spin and/or spin-flavour precession in the magnetic field of the sun are discussed. It is shown without any model…
Basic theoretical and experimental aspects of neutrino magnetic moments are reviewed, including the present best upper bounds from reactor experiments and astrophysics. An interesting effect of neutrino spin precession and oscillations…
We use the constraints arising from primordial nucleosynthesis to bound the strength $F$ of non-standard neutrino-neutrino interactions, when the right-handed neutrinos participate in the interaction. We find $F < 3 \times 10^{-3}\ G_F$,…
If cosmic background neutrinos interact very weakly with each other, through spin-spin interactions, then they may have experienced a phase transition, leading to a ferromagnetic ordering. The small magnetic field resulting from…
We investigate the effect of resonant spin conversion of the neutrinos induced by the geometrical phase in a twisting magnetic field. We find that the geometrical phase originating from the rotation of the transverse magnetic field along…
It is known that if neutrino is a Dirac fermion with magnetic moment, then \nu_L -> \nu_R -> \nu_L transition of supernova neutrinos may occur. The first stage of such transition is due to the neutrino spin flip inside the hot dense…
In this review we discuss the main theoretical aspects and experimental effects of neutrino electromagnetic properties. We start with a general description of the electromagnetic form factors of Dirac and Majorana neutrinos. Then, we…
Oscillations of neutrinos $\nu_L \leftrightarrow \nu_R$ in presence of an arbitrary electromagnetic field are considered. We introduce the Hamiltonian for the neutrino spin evolution equation that accounts for possible effects of…
Using the primordial helium abundance, an upper limit to the magnetic moments for Dirac neutrinos had been provided by imposing restrictions on the number of the additional helicity states. Considering non-thermal photons produced in the…
We obtain a relativistically covariant wave equation for neutrinos in dense matter and electromagnetic field, which describes both flavor oscillations and neutrino spin rotation. Using this equation we construct a quasi-classical theory of…
Massive neutrinos can have helicity $s_{\parallel}\neq -1$. Neutrino helicity changes when the neutrino interacts with an external magnetic field and it is possible that the left-handed neutrinos born inside the Sun or a supernova could…