47,818 research outputs found
Parity-Violating Nuclear Force as derived from QCD Sum Rules
Parity-violating nuclear force, as may be accessed from parity violation
studies in nuclear systems, represents an area of nonleptonic weak interactions
which has been the subject of experimental investigations for several decades.
In the simple meson-exchange picture, parity-violating nuclear force may be
parameterized as arising from exchange of \pi, \rho, \omega, or other meson(s)
with strong meson-nucleon coupling at one vertex and weak parity-violating
meson-nucleon coupling at the other vertex. The QCD sum rule method allows for
a fairly complicated, but nevertheless straightforward, leading-order
loop-contribution determination of the various parity-violating MNN couplings
starting from QCD (with the nontrivial vacuum) and Glashow-Salam-Weinberg
electroweak theory. We continue our earlier investigation of parity-violating
\pi NN coupling (by Henley, Hwang, and Kisslinger) to other parity-violating
couplings. Our predictions are in reasonable overall agreement with the results
estimated on phenomenological grounds, such as in the now classic paper of
Desplanques, Donoghue, and Holstein (DDH), in the global experimental fit of
Adelberger and Haxton (AH), or the effective field theory (EFT) thinking of
Ramsey-Musolf and Page (RP).Comment: 17 pages, 5 figure
Continuous topological phase transitions between clean quantum Hall states
Continuous transitions between states with the {\em same} symmetry but
different topological orders are studied. Clean quantum Hall (QH) liquids with
neutral quasiparticles are shown to have such transitions. For clean bilayer
(nnm) states, a continous transition to other QH states (including non-Abelian
states) can be driven by increasing interlayer repulsion/tunneling. The
effective theories describing the critical points at some transitions are
derived.Comment: 4 pages, RevTeX, 2 eps figure
Polarizing primordial gravitational waves by parity violation
We study primordial gravitational waves (PGWs) in the Horava-Lifshitz (HL)
theory of quantum gravity, in which high-order spatial derivative operators,
including the ones violating parity, generically appear in order for the theory
to be power-counting renormalizable and ultraviolet (UV) complete. Because of
both parity violation and non-adiabatic evolution of the modes due to a
modified dispersion relationship, a large polarization of PGWs becomes
possible, and it could be well within the range of detection of the BB, TB and
EB power spectra of the forthcoming cosmic microwave background (CMB)
observations.Comment: revtex4, 3 figures. Phys. Rev. D87, 103512 (2013
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