Search results for "Charge radius"
showing 10 items of 92 documents
Laser spectroscopy of niobium fission fragments: first use of optical pumping in an ion beam cooler buncher.
2009
A new method of optical pumping in an ion beam cooler buncher has been developed to selectively enhance ionic metastable state populations. The technique permits the study of elements previously inaccessible to laser spectroscopy and has been applied here to the study of Nb. Model independent mean-square charge radii and nuclear moments have been studied for $^{90,90\text{ }\mathrm{m},91,91\text{ }\mathrm{m},92,93,99,101,103}\mathrm{Nb}$ to cover the region of the $N=50$ shell closure and $N\ensuremath{\approx}60$ sudden onset of deformation. The increase in mean-square charge radius is observed to be less than that for Y, with a substantial degree of $\ensuremath{\beta}$ softness observed …
Sensitivities to neutrino electromagnetic properties at the TEXONO experiment
2015
18 pages.- 4 figures.- 1 table
Model-independent determination of the nucleon charge radius from lattice QCD
2020
Lattice QCD calculations of nucleon form factors are restricted to discrete values of the Euclidean four-momentum transfer. Therefore, the extraction of radii typically relies on parametrizing and fitting the lattice QCD data to obtain its slope close to zero momentum transfer. We investigate a new method, which allows to compute the nucleon radius directly from existing lattice QCD data, without assuming a functional form for the momentum dependence of the underlying form factor. The method is illustrated for the case of the isovector mean square charge radius of the nucleon $\langle r^2_\mathrm{isov} \rangle$ and the quark-connected contributions to $\langle r^2_p\rangle$ and $\langle r^2…
Laser Spectroscopy of Neutron-Rich Tin Isotopes: A Discontinuity in Charge Radii across the N=82 Shell Closure
2019
Physical review letters 122(19), 192502 (2019). doi:10.1103/PhysRevLett.122.192502
Nuclear Charge Radius ofBe12
2012
The nuclear charge radius of $^{12}\mathrm{Be}$ was precisely determined using the technique of collinear laser spectroscopy on the $2{s}_{1/2}\ensuremath{\rightarrow}2{p}_{1/2,3/2}$ transition in the ${\mathrm{Be}}^{+}$ ion. The mean square charge radius increases from $^{10}\mathrm{Be}$ to $^{12}\mathrm{Be}$ by $\ensuremath{\delta}⟨{r}_{c}^{2}{⟩}^{10,12}=0.69(5)\text{ }\text{ }{\mathrm{fm}}^{2}$ compared to $\ensuremath{\delta}⟨{r}_{c}^{2}{⟩}^{10,11}=0.49(5)\text{ }\text{ }{\mathrm{fm}}^{2}$ for the one-neutron halo isotope $^{11}\mathrm{Be}$. Calculations in the fermionic molecular dynamics approach show a strong sensitivity of the charge radius to the structure of $^{12}\mathrm{Be}$. Th…
On the definition and observability of the neutrino charge radius
2002
We present a brief summary of recent results concerning the unambiguous definition and experimental extraction of the gauge-invariant and process-independent neutrino charge radius.
The neutrino charge radius is a physical observable
2004
We present a method which allows, at least in principle, the direct extraction of the gauge-invariant and process-independent neutrino charge radius (NCR) from experiments. Under special kinematic conditions, the judicious combination of neutrino and anti-neutrino forward differential cross-sections allows the exclusion of all target-dependent contributions, such as gauge-independent box-graphs, not related to the NCR. We show that the remaining contributions contain universal, renormalization group invariant combinations, such as the electroweak effective charge and the running mixing angle, which must be also separated out. By considering the appropriate number of independent experiments …
The effective neutrino charge radius
2003
It is shown that at one-loop order a neutrino charge radius (NCR) may be defined, which is ultraviolet finite, does not depend on the gauge-fixing parameter, nor on properties of the target other than its electric charge. This is accomplished through the systematic decomposition of physical amplitudes into effective self-energies, vertices, and boxes, which separately respect electroweak gauge invariance. In this way the NCR stems solely from an effective proper photon-neutrino one-loop vertex, which satisfies a naive, QED-like Ward identity. The NCR so defined may be extracted from experiment, at least in principle, by expressing a set of experimental electron-neutrino cross-sections in te…
Systematic study of octet-baryon electromagnetic form factors in covariant chiral perturbation theory
2017
We perform a complete and systematic calculation of the octet-baryon form factors within the fully covariant approach of SU(3) chiral perturbation theory at O(p^3). We use the extended on-mass shell renormalization scheme, and include explicitly the vector mesons and the spin-3/2 decuplet intermediate states. Comparing these predictions with data including magnetic moments, charges, and magnetic radii, we determine the unknown low-energy constants, and give predictions for yet unmeasured observables, such as the magnetic moment of the Sigma^0, and the charge and magnetic radii of the hyperons.
Proton polarizabilities: status, relevance, prospects
2013
This is a brief review of the status of understanding the proton polarizabilities in chiral perturbation theory and of their relevance to the `proton charge radius puzzle'.