Search results for "Malo"

The g-factor of the Electron Bound in Hydrogen-like Ions

1999

The experimental determination of the magnetic moment (g-factor) of the electron bound in hydrogen-like ions represents a clean test of Quantum Electrodynamics, because it is not very sensitive to nuclear structure effects. Experimental data on the g-factor of the bound electron are available only for the hydrogen atom and the 4He+-ion. In this paper we present the first result for the g-factor of hydrogen-like carbon (12C5+). The experimental accuracy is high enough to verify the relativistic contribution to the g-factor on the 10-3 level.

Fits of the baryon magnetic moments

1981

Independent friction-restitution approach to analyze anomalies in normal kinematic restitution in oblique impact

2021

Abstract Oblique impact between rigid bodies is usually described in terms of the coefficients of normal and tangential restitution. When the contact between bodies occurs under elasto-plastic conditions, the normal coefficient of restitution can be ordinarily taken as essentially constant. Several anomalous results reported by Louge and Adams (Anomalous behavior of normal kinematic restitution in the oblique impacts of a hard sphere on an elasto-plastic plate. Phys. Rev. E 65 (2002) 021303), however denoted a significant variation of this coefficient with the incidence angle under certain conditions. This anomalous behavior is interpreted here within the independent friction and restitutio…

Pion Photoproduction on the Nucleon and Light Nuclei

1994

Photo- and electroproduction of mesons are well suited tools to investigate the structure of hadrons. With the advent of electron accelerators with high current and large duty-factor, new classes of experiments including polarization degrees of freedom have become possible. Such investigations range from threshold production of mesons to detailed studies of nucleon resonances. In addition, there is the large field of meson production and propagation in the nuclear medium.

Study of the anomalous magnetic moment of the muon computed from the Adler function

2014

We compute the Adler function on the lattice from vacuum polarization data with twisted boundary conditions using numerical derivatives. The study is based on CLS ensembles with two flavours of $O(a)$ improved Wilson fermions. We extrapolate the lattice data for the Adler function to the continuum limit and to the physical pion mass and analyze its dependence on the momentum transfer. We discuss the application of this method to the extraction of the $u,d$ contribution to $a_\mu^{\mathrm{HLO}}$.

The muon magnetic moment

1981

Muon mass and muon magnetic moment are not calculabIe within the theory of Quantum Eiectrodynamics; they rather define the reference acaie in which masses and energies should be determined when muons are used to test QED or to search for anomalous muon coupiings which couid provide the "raison d'@tre" for the muon. Oniy the anomaious part of the muon magnetic moment experimentaily determined with remarkable precision I), can be oaIculated 2~" Theory and experiment agree preciseiy once corrections being appiied for hadronic and weak processes which poiiute the immaculated fieid of QED at high momentum transfers. Muon mass and muon magnetic moment are, in particular, needed for the interpreta…

Electron dynamical response in InP semiconductors driven by fluctuating electric fields

2015

Abstract The complexity of electron dynamics in low-doped n-type InP crystals operating under fluctuating electric fields is deeply explored and discussed. In this study, we employ a multi-particle Monte Carlo approach to simulate the non-linear transport of electrons inside the semiconductor bulk. All possible scattering events of hot electrons in the medium, the main details of the band structure, as well as the heating effects, are taken into account. The results presented in this study derive from numerical simulations of the electron dynamical response to the application of a sub-Thz electric field, fluctuating for the superimposition of an external source of Gaussian correlated noise.…

The Drell-Hearn-Gerasimov Sum Rule

1994

The Drell-Hearn-Gerasimov (DHG) sum rule relates the helicity structure of the photoabsorption cross section to the anomalous magnetic moment of the nucleon. It is based on Lorentz and gauge invariance, crossing symmetry, causality and unitarity. A generalized DHG sum rule my be derived for virtual photons. At low momentum transfer this generalized sum rule is saturated by the resonance region, at high momentum transfer it may be expressed by the parton spin distributions measured in deep inelastic scattering. The longitudinal-transverse interference determines the Cottingham sum rule, which is related to the electric and magnetic form factors over the whole range of momentum transfer.

Towards electronic g-factor measurements in medium-heavy hydrogen-like and lithium-like ions

2005

Abstract Measurements of the anomalous magnetic moment of the electron bound in hydrogen-like ions with spinless nuclei have proven to be highly sensitive tests of corresponding calculations based on bound-state quantum electrodynamics. Measurements performed on H-like carbon 12C5+ and oxygen 16O7+ together with bound-state QED calculations on the same level of accuracy have achieved sensitivities around 0.25% of the QED bound state contributions to the calculated electronic g-factors of these ions. Currently, a similar experiment on hydrogen-like calcium 40Ca19+, lithium-like calcium 40Ca17+ and other medium-heavy ions is being prepared, which is capable of increasing this sensitivity on t…

The hadronic light-by-light contribution to the muon's anomalous magnetic moment

2019

In view of the current 3 - 4 $\sigma$ deviation between theoretical and experimental values for the muon's anomalous magnetic moment, we review the ongoing efforts in constraining the hadronic light-by-light contribution to $a_\mu$ by using dispersive techniques combined with a dedicated experimental program to obtain the required hadronic input.