Search results for "nucl-ex"
showing 10 items of 1009 documents
Study of the magnetic octupole moment of $^{173}$Yb using collinear laser spectroscopy
2020
The hyperfine constants of the $^3$P$^{\circ}_2$ state in neutral Yb have been measured using three different dipole transitions. This state was recently shown to have a comparatively large hyperfine magnetic octupole splitting, and thus a puzzlingly large magnetic octupole moment. The measurement is performed using collinear laser spectroscopy on a fast atomic beam, which provides a straightforward route to probing long-lived metastable atomic states with high resolution. From the combined analysis of all three lines we find no significant evidence for a non-zero octupole moment in $^{173}$Yb.
Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination
2010
Changes in the mean-square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a new laser spectroscopic approach to determine the charge radii of lithium isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8 ms lifetime isotope with production rates on the order of only 10,000 atoms/s. The method was applied to all bound iso…
Sympathetic cooling schemes for separately trapped ions coupled via image currents
2021
Cooling of particles to mK-temperatures is essential for a variety of experiments with trapped charged particles. However, many species of interest lack suitable electronic transitions for direct laser cooling. We study theoretically the remote sympathetic cooling of a single proton with laser-cooled $^9$Be$^+$ in a double-Penning-trap system. We investigate three different cooling schemes and find, based on analytical calculations and numerical simulations, that two of them are capable of achieving proton temperatures of about 10 mK with cooling times on the order of 10 s. In contrast, established methods such as feedback-enhanced resistive cooling with image-current detectors are limited …
Antineutrino induced Λ(1405) production off the proton
2015
We have studied the strangeness-changing antineutrino-induced reactions ${\overline{\ensuremath{\nu}}}_{l}p\ensuremath{\rightarrow}{l}^{+}\ensuremath{\phi}B$, with $\ensuremath{\phi}B={K}^{\ensuremath{-}}p$, ${\overline{K}}^{0}n$, ${\ensuremath{\pi}}^{0}\ensuremath{\Lambda}$, ${\ensuremath{\pi}}^{0}{\ensuremath{\Sigma}}^{0}$, $\ensuremath{\eta}\ensuremath{\Lambda}$, $\ensuremath{\eta}{\ensuremath{\Sigma}}^{0}$, ${\ensuremath{\pi}}^{+}{\ensuremath{\Sigma}}^{\ensuremath{-}}$, ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\Sigma}}^{+}$, ${K}^{+}{\ensuremath{\Xi}}^{\ensuremath{-}}$, and ${K}^{0}{\ensuremath{\Xi}}^{0}$, using a chiral unitary approach. These ten coupled channels are allowed t…
Mass measurements beyond the major r-process waiting point $^{80}$Zn
2008
High-precision mass measurements on neutron-rich zinc isotopes 71m,72-81Zn have been performed with the Penning trap mass spectrometer ISOLTRAP. For the first time the mass of 81Zn has been experimentally determined. This makes 80Zn the first of the few major waiting points along the path of the astrophysical rapid neutron capture process where neutron separation energy and neutron capture Q-value are determined experimentally. As a consequence, the astrophysical conditions required for this waiting point and its associated abundance signatures to occur in r-process models can now be mapped precisely. The measurements also confirm the robustness of the N = 50 shell closure for Z = 30 farthe…
New Measurements of the Beam Normal Spin Asymmetries at Large Backward Angles with Hydrogen and Deuterium Targets
2017
International audience; New measurements of the beam normal single spin asymmetry in the electron elastic and quasielastic scattering on the proton and deuteron, respectively, at large backward angles and at ⟨Q2⟩=0.22 (GeV/c)2 and ⟨Q2⟩=0.35 ( GeV/c)2 are reported. The experimentally observed asymmetries are compared with the theoretical calculation of Pasquini and Vanderhaeghen [Phys. Rev. C 70, 045206 (2004).PRVCAN0556-281310.1103/PhysRevC.70.045206]. The agreement of the measurements with the theoretical calculations shows a dominance of the inelastic intermediate excited states of the nucleon, πN and the Δ resonance. The measurements explore a new, important parameter region of the exc…
Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering
2017
A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality $Q^{2}>1$ (GeV/$c$)$^2$, invariant mass of the hadronic system $W > 5$ GeV/$c^2$, Bjorken scaling variable in the range $0.003 < x < 0.4$, fraction of the virtual photon energy carried by the hadron in the range $0.2 < z < 0.8$, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/$c)^2 < P_{\rm{hT}}^{2} < 3$ (GeV/$c$)$^2$. The multiplicities are pres…
Evidence of a sudden increase in the nuclear size of proton-rich silver-96
2021
Understanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus 100Sn, where the near-equal number of protons (Z) and neutrons (N) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the N = 50 magic neutron number in the silver isotopic chain with th…
Analytic response relativistic coupled-cluster theory: the first application to indium isotope shifts
2019
With increasing demand for accurate calculation of isotope shifts of atomic systems for fundamental and nuclear structure research, an analytic energy derivative approach is presented in the relativistic coupled-cluster theory framework to determine the atomic field shift and mass shift factors. This approach allows the determination of expectation values of atomic operators, overcoming fundamental problems that are present in existing atomic physics methods, i.e. it satisfies the Hellmann-Feynman theorem, does not involve any non-terminating series, and is free from choice of any perturbative parameter. As a proof of concept, the developed analytic response relativistic coupled-cluster the…
Proton-neutron pairing correlations in the self-conjugate nucleus 42Sc
2021
Collinear laser spectroscopy of the N=Z=21 self-conjugate nucleus 42Sc has been performed at the JYFL IGISOL IV facility in order to determine the change in nuclear mean-square charge radius between the Iπ=0+ ground state and the Iπ=7+ isomer via the measurement of the 42g,42mSc isomer shift. New multi-configurational Dirac-Fock calculations for the atomic mass shift and field shift factors have enabled a recalibration of the charge radii of the 42−46Sc isotopes which were measured previously. While consistent with the treatment of proton-neutron, proton-proton and neutron-neutron pairing on an equal footing, the reduction in size for the isomer is observed to be of a significantly larger m…