Search results for "pole [approximation]"
showing 10 items of 522 documents
Pseudoscalar transition form factors: (g − 2) of the muon, pseudoscalar decays into lepton pairs, and the η – η′ mixing
2015
We present our model-independent and data-driven method to describe pseudoscalar meson transition form factors in the space- and (low-energy) time-like regions. The method is general and conforms a toolkit applicable to any other form factor, of one and two variables, with the potential to include both high- and low-energy QCD constraints altogether. The method makes use of analyticity and unitary properties of form factors, it is simple, systematic and can be improved upon by including new data. In the present discussion, the method is used to show the impact of experimental data for precision calculations in the low-energy sector of the Standard Model. In particular, due to its relevance …
SIMPRE1.2: Considering the hyperfine and quadrupolar couplings and the nuclear spin bath decoherence
2016
SIMPRE is a fortran77code which uses an effective electrostatic model of point charges to predict the magnetic behavior of rare-earth-based mononuclear complexes. In this manuscript, we present SIMPRE1.2, which now takes into account two further phenomena.Firstly, SIMPRE now considers the hyperfine and quadrupolar interactions within the rare-earth ion, resulting in a more complete and realistic set of energy levels and wave functions. Secondly,and in order to widen SIMPRE’s predictive capabilities regarding potential molecular spin qubits, it now includes a routine that calculates an upper-bound estimate of the decoherence time considering only the dipolar coupling between the electron spi…
Improved bounds on heavy quark electric dipole moments
2020
New bounds on the electric dipole moment (EDM) of charm and bottom quarks are derived using the stringent limits on their chromo-EDMs. The new limits, $|d_c|<1.5\times10^{-21}\:e\,\text{cm}$ and $|d_b|< 1.2\times 10^{-20}\:e\,\text{cm}$, improve the previous ones by about three orders of magnitude. These indirect bounds have implications for different models of new physics, including two-Higgs-doublet, leptoquarks, and supersymmetry models.
Highly-spherical Top Data System (HTDS) software for spectrum simulation of octahedral XY6 molecules
2000
Abstract The Spherical Top Data System (STDS) program suite developed in Dijon has been extended into two directions. First, the vibrational extrapolation is now possible for any kind of polyad scheme, this one being fully specified in the input parameters of the programs for hamiltonian and transition moment model calculations. This was not the case of the preceding version which was based on the polyad scheme of methane. Secondly, it is now possible to study any band and polyad of XY 6 molecule for which a complete treatment in the O h group is made. Up to now, only some vibrational levels of these molecules ( F 1u levels in particular) could be studied using equivalences with the T d gro…
top data system ( TDS) software for infrared spectrum simulation of asymmetric molecules: some improvements to the TDS packages
2005
Abstract The spherical top data system (STDS) program suite developed in Dijon has been extended with the aim of studying any rovibrational band or polyad of XY 2 Z 2 ( C 2 v ) asymmetric top molecules. We work in the O ( 3 ) ⊃ T d ⊃ C 2 v chain because these species result from the substitution of two ligands of a corresponding “parent” spherical top and thus are relatively close to tetrahedral symmetry. The choice of this group chain has consequences on the method used to specify the input parameters of the programs for Hamiltonian and transition moment model calculations. One example concerning the ground state of the SO2F2 quasi-spherical molecule is presented. As before, this suite con…
C4v Top Data System (C4v TDS) software for infrared spectrum simulation of XY5Z symmetric molecules
2002
Abstract The Highly spherical Top Data System program suite developed in Dijon has been extended in the aim of studying any rovibrational band or polyad of XY5Z (C4v) symmetric top molecules. We work in the O(3)⊃Oh⊃C4v chain because most of these species result from the substitution of one ligand of the corresponding spherical tops and thus are relatively close to octahedral symmetry. The choice of this group chain has consequences in the way in which it is used to specify the input parameters of the programs for Hamiltonian and transition moment model calculations. One example concerning the ν1/ν8 dyad of the SF 5 35 Cl molecule is presented. As before, this suite consists of a series of F…
Spin-one-Ising model for (CO)1?x (N2) x mixtures: A finite size scaling study of random-field-type critical phenomena
1995
A qualitative model for solid mixtures of diatomic molecules, where one species (called CO, to be specific) carries both a dipole moment and a quadrupole moment, while the other species (calledN 2) has only a quadrupole moment, is studied by Monte Carlo methods. We use spinsS i =±1 to represent the orientations of the CO electric dipole moment, if the lattice sitei is taken by a CO molecule, whileS i =0 if the site is taken by anN 2 molecule. Assuming nearest-neighbor antiferroelectric interactions between CO molecules, and a bilinear dipole-quadrupole coupling between CO andN 2, the randomly quenchedN 2 molecules act like random fields do in the random field Ising model. In previous work i…
Experimental Constraint on Axionlike Particles over Seven Orders of Magnitude in Mass
2021
We use our recent electric dipole moment (EDM) measurement data to constrain the possibility that the HfF+ EDM oscillates in time due to interactions with candidate dark matter axionlike particles (ALPs). We employ a Bayesian analysis method which accounts for both the look-elsewhere effect and the uncertainties associated with stochastic density fluctuations in the ALP field. We find no evidence of an oscillating EDM over a range spanning from 27 nHz to 400 mHz, and we use this result to constrain the ALP-gluon coupling over the mass range 10-22-10-15 eV. This is the first laboratory constraint on the ALP-gluon coupling in the 10-17-10-15 eV range, and the first laboratory constraint to pr…
Magnetic moment of the Roper resonance
2012
The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.
The magnetic moment anomaly of the electron bound in hydrogen-like oxygen16O7
2003
The measurement of the g-factor of the electron bound in a hydrogen-like ion is a high-accuracy test of the theory of quantum electrodynamics (QED) in strong fields. Here we report on the measurement of the g-factor of the bound electron in hydrogen-like oxygen (16O7+). In our experiment a single highly charged ion is stored in a Penning trap. The electronic spin state of the ion is monitored via the continuous Stern?Gerlach effect in a quantum non-demolition measurement. Quantum jumps between the two spin states (spin up and spin down) are induced by a microwave field at the spin precession frequency of the bound electron. The g-factor of the bound electron is obtained by varying the micro…