55,627 research outputs found
Compositeness Effects in the Anomalous Weak-Magnetic Moment of Leptons
We investigate the effects induced by excited leptons, at the one-loop level,
in the anomalous magnetic and weak-magnetic form factors of the leptons. Using
a general effective Lagrangian approach to describe the couplings of the
excited leptons, we compute their contributions to the weak-magnetic moment of
the lepton, which can be measured on the peak, and we compare it
with the contributions to , measured at low energies.Comment: Latex File using Rev Tex. 16 pages 5 .eps figure
Neutrino Discovery Limit of Dark Matter Direct Detection Experiments in the Presence of Non-Standard Interactions
The detection of coherent neutrino-nucleus scattering by the COHERENT
collaboration has set on quantitative grounds the existence of an irreducible
neutrino background in direct detection searches of Weakly Interacting Massive
Dark Matter candidates. This background leads to an ultimate discovery limit
for these experiments: a minimum Dark Matter interaction cross section below
which events produced by the coherent neutrino scattering will mimic the Dark
Matter signal, the so-called \emph{neutrino floor}. In this work we study the
modification of such neutrino floor induced by non-standard neutrino
interactions within their presently allowed values by the global analysis of
oscillation and COHERENT data. By using the full likelihood information of such
global analysis we consistently account for the correlated effects of
non-standard neutrino interactions both in the neutrino propagation in matter
and in its interaction in the detector. We quantify their impact on the
neutrino floor for five future experiments: DARWIN (Xe), ARGO (Ar), Super-CDMS
HV (Ge and Si) and CRESST phase III (CaWO). Quantitatively, we find that
non-standard neutrino interactions allowed at the level can result in
an increase of the neutrino floor of up to a factor with respect to
the Standard Model expectations and impact the expected sensitivities of the
ARGO, CRESST phase III and DARWIN experiments.Comment: 21 pages, 4 figures. Matches version published in the JHEP. Corrected
exposure and results for CRESST phase II
Radiatively Induced Lorentz and CPT Violation in Schwinger Constant Field Approximation
The Schwinger proper-time method is an effective calculation method,
explicitly gauge invariant and nonperturbative. We make use of this method to
investigate the radiatively induced Lorentz and CPT-violating effects in
quantum electrodynamics when an axial vector interaction term is introduced in
the fermionic sector. The induced Lorentz and CPT-violating Chern-Simons term
coincides with the one obtained using a covariant derivative expansion but
differs from the result usually obtained in other regularization schemes. A
possible ambiguity in the approach is also discussed.Comment: 11 pages, REVTeX, typos and a few equations corrected, a comment
added to the conclusions, acknowledgments adde
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