Search results for "Signal processing"

2019

The atomic spectrum of neutral promethium has been studied extensively by laser resonance ionization spectroscopy. We report on more than 1000 atomic transitions in the blue and near infrared spectral ranges, most of them between high excited energy levels. As Rydberg convergences could not be assigned unambiguously in the dense spectrum at high excitation energies, the first ionization potential (IP) was determined via field ionization of weakly bound states within a static electric field. By applying the saddle-point model, a value of ${\mathrm{IP}}_{(\mathrm{Pm})}=45\phantom{\rule{0.16em}{0ex}}020.8(3)\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1} [5.58188(4)\phantom{\rule{0.16…

Electronic structure of Rf+ (Z=104) from ab initio calculations

2021

We report calculation of the energy spectrum and the spectroscopic properties of the superheavy element ion: ${\mathrm{Rf}}^{+}$. We use the four-component relativistic Dirac-Coulomb Hamiltonian and the multireference configuration interaction model to tackle the complex electronic structure problem that combines strong relativistic effects and electron correlation. We determine the energies of the ground and the low-lying excited states of ${\mathrm{Rf}}^{+}$, which originate from the $7{s}^{2}6{d}^{1},\phantom{\rule{0.28em}{0ex}}7{s}^{1}6{d}^{2},\phantom{\rule{0.28em}{0ex}}7{s}^{2}7{p}^{1}$, and $7{s}^{1}6{d}^{1}7{p}^{1}$ configurations. The results are discussed vis-\`a-vis the lighter h…

Resonance State inH7

2007

The existence of the $^{7}\mathrm{H}$ nuclear system was investigated via a one-proton transfer reaction with a $^{8}\mathrm{He}$ beam at $15.4\mathrm{A}\text{ }\text{ }\mathrm{MeV}$ and a $^{12}\mathrm{C}$ gas target. The experimental setup was based on the active-target MAYA which allowed a complete reconstruction of the reaction kinematics. The existence of the $^{7}\mathrm{H}$ was confirmed with the identification of seven events where the system was formed with a resonance energy of ${0.57}_{\ensuremath{-}0.21}^{+0.42}\text{ }\text{ }\mathrm{MeV}$ above the $^{3}\mathrm{H}+4n$ threshold and a resonance width of ${0.09}_{\ensuremath{-}0.06}^{+0.94}\text{ }\text{ }\mathrm{MeV}$. This stu…

Neutron polarizabilities investigated by quasi-free Compton scattering from the deuteron

2002

Measuring Compton scattered photons and recoil neutrons in coincidence, quasifree Compton scattering by the neutron has been investigated at MAMI (Mainz) at ${\ensuremath{\theta}}_{\ensuremath{\gamma}}^{\mathrm{lab}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}136\ifmmode^\circ\else\textdegree\fi{}$ in an energy range from 200 to 400 MeV. From the data a polarizability difference of ${\ensuremath{\alpha}}_{n}\ensuremath{-}{\ensuremath{\beta}}_{n}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}9.8\ifmmode\pm\else\textpm\fi{}3.6(\mathrm{stat}{)}_{\ensuremath{-}1.1}^{+2.1}(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}2.2(\mathrm{model})$ in units of ${10}^{\ensuremath{-}4}{\mathrm{fm}}^{…

C15 : From halo effective field theory structure to the study of transfer, breakup, and radiative-capture reactions

2019

Background: Aside from being a one-neutron halo nucleus, $^{15}\mathrm{C}$ is interesting because it is involved in reactions of relevance for several nucleosynthesis scenarios.Purpose: The aim of this work is to analyze various reactions involving $^{15}\mathrm{C}$, using a single structure model based on halo effective field theory (halo EFT) following the excellent results obtained in [P. Capel et al., Phys. Rev. C 98, 034610 (2018)].Method: To develop a halo-EFT model of $^{15}\mathrm{C}$ at next to leading order (NLO), we first extract the asymptotic normalization coefficient (ANC) of its ground state by analyzing $^{14}\mathrm{C}(d,p)^{15}\mathrm{C}$ transfer data at low energy using …

α -decay spectroscopy of the N=130 isotones Ra218 and Th220 : Mitigation of α -particle energy summing with implanted nuclei

2019

© 2019 American Physical Society. An analysis technique has been developed in order to mitigate energy summing due to sequential short-lived α decays from nuclei implanted into a silicon detector. Using this technique, α-decay spectroscopy of the N=130 isotones Ra218 (Z=88) and Th220 (Z=90) has been performed. The energies of the α particles emitted in the Ra218→Rn214 and Th220→Ra216 ground-state-to-ground-state decays have been measured to be 8381(4) keV and 8818(13) keV, respectively. The half-lives of the ground states of Ra218 and Th220 have been measured to be 25.99(10) μs and 10.4(4) μs, respectively. The half-lives of the ground states of the α-decay daughters, Rn214 and Ra216, have …

Observation of e+e−→ϕχc1 and ϕχc2 at s=4.600  GeV

2018

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of root s = 4.600 GeV, we search for the production of e(+)e(-) -> phi chi( ...

Observation of the Bottomonium Ground State in the Decay Υ(3S)→γηb

2008

The authors report the results of a search for the bottomonium ground state {eta}{sub b}(1S) in the photon energy spectrum with a sample of (109 {+-} 1) million of {Upsilon}(3S) recorded at the {Upsilon}(3S) recorded at the {Upsilon}(3S) energy with the BABAR detector at the PEP-II B factory at SLAC. They observe a peak in the photon energy spectrum at E{sub {gamma}} = 921.2{sub -2.8}{sup +2.1}(stat) {+-} 2.4(syst) MeV with a significance of 10 standard deviations. They interpret the observed peak as being due to monochromatic photons from the radiative transition {Upsilon}(3S) {yields} {gamma} {eta}{sub b}(1S). This photon energy corresponds to an {eta}{sub b}(1S) mass of 9388.9{sub -2.3}{…

Second-forbidden nonunique β− decays of Na24 and Cl36 assessed by the nuclear shell model

2020

We have performed a systematic study of the $logft$ values, shape factors, and electron spectra for the second-forbidden nonunique ${\ensuremath{\beta}}^{\ensuremath{-}}$ decays of $^{24}\mathrm{Na}({4}^{+})\ensuremath{\rightarrow}^{24}\mathrm{Mg}({2}^{+})$ and $^{36}\mathrm{Cl}({2}^{+}){\ensuremath{\rightarrow}}^{36}\mathrm{Ar}({0}^{+})$ transitions under the framework of the nuclear shell model. We have performed the shell model calculations in the $sd$ model space, using more recent microscopic effective interactions such as Daejeon16, chiral N3LO, and JISP16. These interactions are derived from the no-core shell model wave functions using Okubo-Lee-Suzuki transformation. For comparison,…

Radiative decays in bottomonium beyond the long wavelength approximation

2019

We revisit the nonrelativistic quark model description of electromagnetic radiative decays in bottomonium. We show that even for the simplest spectroscopic quark model the calculated widths can be in good agreement with data once the experimental masses of bottomonium states and the photon energy are properly implemented in the calculation. For transitions involving the lower lying spectral states this implementation can be easily done via the Long Wave Length approximation. For transitions where this approximation does not apply we develop a new method of implementing the experimental energy dependencies.