Mon·Nov 21, 2016Monday·November 21, 2016

1. 01*

   Electroweak Decay Studies of Highly Charged Radioactive Ions with TITAN at TRIUMF

   K.G. Leach🇨🇦 · I. Dillmann🇨🇦 · R. Klawitter🇨🇦 · E. Leistenschneider🇨🇦 · A. Lennarz🇨🇦 · T. Brunner🇨🇦 · D. Frekers🇩🇪 · C. Andreiou🇨🇦 · A.A. Kwiatkowski🇨🇦 · J. Dilling🇨🇦

   Several modes of electroweak radioactive decay require an interaction between the nucleus and bound electrons within the constituent atom. Thus, the probabilities of the respective decays are not only influenced by the structure of the initial and final states in the nucleus, but can also depend strongly on the atomic charge. Conditions suitable for the partial or complete ionization of these rare isotopes occur naturally in hot, dense astrophysical environments, but can also be artificially generated in the laboratory to selectively block certain radioactive decay modes. Direct experimental studies on such scenarios are extremely difficult due to the laboratory conditions required to generate and store radioactive ions at high charge states. A new electron-beam ion trap (EBIT) decay setup with the TITAN experiment at TRIUMF has successfully demonstrated such techniques for performing spectroscopy on the radioactive decay of highly charged ions.

   nucl-exphysics.atom-phphysics.ins-det0 citations
2. 02*

   A Common Optical Potential for ${}^4$He+${}^{12}$C at Intermediate Energies

   Li-Yuan Hu🇨🇳 · Yu-Shou Song🇰🇷 · Ying-Wei Hou🇨🇳 · Hui-Lan Liu🇨🇳

   A common optical potential for ${}^4$He+${}^{12}$C at intermediate bombarding energies, which is essential in analyzing exotic nuclei with ${}^4$He clusters, was obtained based on the São Paulo potential (SPP). Among systematic optical potentials for ${}^4$He+${}^{12}$C, this potential has the merit of using a fixed imaginary part of Woods-Saxon form. By optical-model calculations, this potential reproduced the experimental elastic scattering angular distributions of ${}^4$He+${}^{12}$C well within the energy range of 26\,$A$--60\,$A$ MeV. It was also applied successfully in calculations of the breakup reactions of ${}^6$Li+${}^{12}$C and ${}^6$He+${}^{12}$C with a three-body continuum discretized coupled-channels method.

   nucl-exphysics.data-an0 citations
3. 03*

   Nucleon resonance structure in the finite volume of lattice QCD

   Jia-Jun Wu🇦🇺 · H. Kamano🇯🇵 · T.-S. H. Lee🇺🇸 · D. B. Leinweber🇦🇺 · A.W. Thomas🇦🇺

   An approach for relating the nucleon resonances extracted from $\pi N$ reaction data to lattice QCD calculations has been developed by using the finite-volume Hamiltonian method. Within models of $\pi N$ reactions, bare states are introduced to parametrize the intrinsic excitations of the nucleon. We show that the resonance pole positions can be related to the probability $P_{N^{\ast }}(E)$ of finding the bare state, $N^{\ast }$, in the $\pi N$ scattering states in infinite volume. We further demonstrate that the probability $P_{N^{\ast }}^V(E)$ of finding the same bare states in the eigenfunctions of the underlying Hamiltonian in finite volume approaches $P_{N^{\ast }}(E)$ as the volume increases. Our findings suggest that the comparison of $P_{N^{\ast }}(E)$ and $P_{N^{\ast }}^V(E)$ can be used to examine whether the nucleon resonances extracted from the $\pi N$ reaction data within the dynamical models are consistent with lattice QCD calculation. We also discuss the measurement of $P_{N^{\ast }}^V(E)$ directly from lattice QCD. The practical differences between our approach and the approach using the Lüscher formalism to relate LQCD calculations to the nucleon resonance poles embedded in the data are also discussed.

   ↳ hep-lathep-phnucl-exnucl-thPRD(2017)·22 citations
4. 04*

   Two-photon exchange correction to $2S$-$2P$ splitting in muonic helium-3 ions

   Carl E. Carlson🇺🇸 · Mikhail Gorchtein🇩🇪 · Marc Vanderhaeghen🇩🇪

   We calculate the two-photon exchange correction to the Lamb shift in muonic helium-3 ions within the dispersion relations framework. Part of the effort entailed making analytic fits to the electron-${}^3$He quasielastic scattering data set, for purposes of doing the dispersion integrals. Our result is that the energy of the 2$S$ state is shifted downwards by two-photon exchange effects by 15.14(49) meV, in good accord with the result obtained from a potential model and effective field theory calculation.

   ↳ nucl-thhep-phnucl-exPRA(2017)·37 citations
5. 05*

   Limits on uranium and thorium bulk content in GERDA Phase I detectors

   GERDA collaboration · M. Agostini · M. Allardt · A.M. Bakalyarov · M. Balata · I. Barabanov · L. Baudis · C. Bauer · N. Becerici-Schmidt · E. Bellotti · S. Belogurov · S.T. Belyaev and 104 other authors

   Internal contaminations of ${}^{238}$U, ${}^{235}$U and ${}^{232}$Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of ${}^{76}$Ge. The data from GERDA Phase~I have been analyzed for alpha events from the decay chain of these contaminations by looking for full decay chains and for time correlations between successive decays in the same detector. No candidate events for a full chain have been found. Upper limits on the activities in the range of a few nBq/kg for ${}^{226}$Ra, ${}^{227}$Ac and ${}^{228}$Th, the long-lived daughter nuclides of ${}^{238}$U, ${}^{235}$U and ${}^{232}$Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from ${}^{226}$Ra and ${}^{228}$Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.

   ↳ physics.ins-detnucl-exAstropart.Phys.(2017)·20 citations
6. 06*

   $\beta$-particle energy-summing correction for $\beta$-delayed proton emission measurements

   Z. Meisel🇺🇸 · M. del Santo🇺🇸 · H.L. Crawford🇺🇸 · R.H. Cyburt🇺🇸 · G.F. Grinyer🇫🇷 · C. Langer🇩🇪 · F. Montes🇺🇸 · H. Schatz🇺🇸 · K. Smith🇺🇸

   A common approach to studying $\beta$-delayed proton emission is to measure the energy of the emitted proton and corresponding nuclear recoil in a double-sided silicon-strip detector (DSSD) after implanting the $\beta$-delayed proton emitting ($\beta$p) nucleus. However, in order to extract the proton-decay energy, the measured energy must be corrected for the additional energy implanted in the DSSD by the $\beta$-particle emitted from the $\beta$p nucleus, an effect referred to here as $\beta$-summing. We present an approach to determine an accurate correction for $\beta$-summing. Our method relies on the determination of the mean implantation depth of the $\beta$p nucleus within the DSSD by analyzing the shape of the total (proton + recoil + $\beta$) decay energy distribution shape. We validate this approach with other mean implantation depth measurement techniques that take advantage of energy deposition within DSSDs upstream and downstream of the implantation DSSD.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2017)·7 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.