8,817 research outputs found
Limits on Neutron Lorentz Violation from Pulsar Timing
Pulsars are the most accurate naturally occurring clocks, and data about them
can be used to set bounds on neutron-sector Lorentz violations. If SO(3)
rotation symmetry is completely broken for neutrons, then pulsars' rotation
speeds will vary periodically. Pulsar timing data limits the relevant
Lorentz-violating coefficients to be smaller than 1.7 x 10^(-8) at at least 90%
confidence.Comment: 10 pages, version to appear in Phys. Rev.
Lorentz Violation and Faddeev-Popov Ghosts
We consider how Lorentz-violating interactions in the Faddeev-Popov ghost
sector will affect scalar QED. The behavior depends sensitively on whether the
gauge symmetry is spontaneously broken. If the symmetry is not broken, Lorentz
violations in the ghost sector are unphysical, but if there is spontaneous
breaking, radiative corrections will induce Lorentz-violating and
gauge-dependent terms in other sectors of the theory.Comment: 13 page
Eliminating the CPT-Odd f Coefficient from the Lorentz-Violating Standard Model Extension
The fermionic f coefficient in the Lorentz-violating standard model extension
presents a puzzle. Thus far, no observable quantity that depends upon f has
ever been found. We show that this is because f is actually unnecessary. It has
absolutely no effects at leading order and can be completely absorbed into
other coefficients of the theory by a redefinition of the field.Comment: 12 page
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