کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1860533 | 1037438 | 2016 | 7 صفحه PDF | دانلود رایگان |
• The helicity of chiral particles coupled minimally is conserved.
• For non-minimal coupling the helicity may not be conserved.
• Motion in electric field provides example when helicity is not conserved.
• When coupled non-minimally the helicity is not boost-invariant.
• When coupled minimally to gravitation, helicity is conserved.
The helicity of a free massless relativistic particle, χo=s⋅p/|p|χo=s⋅p/|p|, is generalized, for a particle in an electromagnetic field, to χ=s⋅p/Eχ=s⋅p/E where EE is energy. Both χoχo and χ coincide and are conserved for minimal coupling (gyromagnetic ratio g=0g=0) but are different and neither of them is conserved when the coupling is non-minimal, g≠0g≠0, generating non-zero effective mass. For a chiral particle with g=2g=2 in a constant electric field both helicities converge asymptotically to the same value. Helicity is also conserved for minimal gravitational coupling.
Journal: Physics Letters A - Volume 380, Issue 20, 29 April 2016, Pages 1677–1683