22,703 research outputs found
Vus and neutron beta decay
We discuss the effect of the recent change of by three standard
deviations on the standard model predictions for neutron beta decay
observables. We also discuss the effect the experimental error bars of have on such predictions. Refined precision tests of the standard model
will be made by a combined effort to improve measurements in neutron beta decay
and in strangeness-changing decays. By itself the former will yield very
precise measurements of and make also very precise predictions for
Finite width induced modification to the electromagnetic form factors of spin-1 particles
The inclusion of the unstable features of a spin-1 particle, without breaking
the electromagnetic gauge invariance, can be properly accomplished by including
higher order contributions as done in the so-called fermion loop scheme (for
the W gauge boson), and the boson loop scheme (for vector mesons). This induces
a non trivial modification to the electromagnetic vertex of the particle, which
must be considered in addition to any other contribution computed as stable
particles. Considering the modified electromagnetic vertex, we obtain general
expressions for the corresponding corrections to the multipoles as a function
of the mass of the particles in the loop. For the W gauge boson no substantial
deviations from the stable case is observed. For the rho and K* mesons the mass
of the particles in the loop makes a significant effect, and can be comparable
with corrections of different nature .Comment: 11 pages, 1 figure. Extended discussion, main equations rewritten to
exhibit limiting behavior. Results for K* meson added. Accepted for
publication in PR
Coherent elastic neutrino-nucleus scattering as a precision test for the Standard Model and beyond: the COHERENT proposal case
Several experimental proposals expect to confirm the recent measurement of
the coherent elastic neutrino-nucleus scattering (CEvNS). Motivated in
particular by the next generation experiments of the COHERENT collaboration, we
study their sensitivity to different tests of the Standard Model and beyond. We
analyze the resolution that can be achieved by each future proposed detector in
the measurement of the weak mixing angle; we also perform similar analysis in
the context of Non-Standard Interaction (NSI) and in the case of an oscillation
into a sterile neutrino state. We show that the future perspectives are
interesting for these types of new physics searches.Comment: 19 pages, 7 figures, to appear in Advances in High Energy Physic
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