Wed·May 15, 2019Wednesday·May 15, 2019

1. 01*

   Hyperon I: Study of the $\Lambda (1405)$

   A.V. Anisovich🇩🇪 · A.V. Sarantsev🇩🇪 · V.A. Nikonov🇩🇪 · V. Burkert🇺🇸 · R.A. Schumacher🇺🇸 · U. Thoma🇩🇪 · E. Klempt🇩🇪

   Low-energy data on the three charge states in $\gamma p\to K^{+}(\Sigma \pi )$ from CLAS at JLab, on $K^{-}p\to {\pi }^0{\pi }^0\Lambda$ and ${\pi }^0{\pi }^0\Sigma$ from the Crystal Ball at BNL, bubble chamber data on $K^{-}p\to {\pi }^{-}{\pi }^{+}{\pi }^{\pm }{\Sigma }^{\mp }$, low-energy total cross sections on $K^{-}$ induced reactions, and data on the $K^{-}p$ atom are fitted with the BnGa partial-wave-analysis program. We find that the data can be fitted well with just one isoscalar spin-1/2 negative-parity pole, the $\Lambda (1405)$, and background contributions.

   nucl-exnucl-th8 citations
2. 02*

   Direct decay-energy measurement as a route to the neutrino mass

   Jonas Karthein🇨🇭 · Dinko Atanasov🇩🇪 · Klaus Blaum🇩🇪 · Sergey Eliseev🇩🇪 · Pavel Filianin🇩🇪 · David Lunney🇫🇷 · Vladimir Manea🇨🇭 · Maxime Mougeot🇫🇷 · Dennis Neidherr🇩🇪 · Yuri Novikov🇷🇺 · Lutz Schweikhard🇩🇪 · Andree Welker🇨🇭 · Frank Wienholtz🇨🇭 · Kai Zuber🇩🇪

   A high-precision measurement of the ${}^{131}$Cs${\to }^{131}$Xe ground-to-ground-state electron-capture $Q_{\text{EC}}$-value was performed using the ISOLTRAP mass spectrometer at ISOLDE/CERN. The novel PI-ICR technique allowed to reach a relative mass precision $\delta m/m$ of $1.4\cdot 10^{-9}$. A mass resolving power $m/\Delta m$ exceeding $1\cdot 10^7$ was obtained in only $1$s trapping time. Allowed electron-capture transitions with sub-keV or lower decay energies are of high interest for the direct determination of the ${\nu }_e$ mass. The new measurement improves the uncertainty on the ground-to-ground-state $Q_{\text{EC}}$-value by a factor 25 precluding the ${}^{131}$Cs${\to }^{131}$Xe pair as a feasible candidate for the direct determination of the ${\nu }_e$ mass.

   nucl-exHyperfine Interact.(2019)·20 citations
3. 03*

   Quadrupole Moments of 29Mg and 33Mg

   Deyan Todorov Yordanov🇫🇷 · Magdalena Kowalska🇨🇭 · Klaus Blaum🇩🇪 · Marieke De Rydt🇧🇪 · Kieran T. Flanagan🇬🇧 · Pieter Himpe🇧🇪 · Peter Lievens🇧🇪 · Stephen Mallion🇧🇪 · Rainer Neugart🇩🇪 · Gerda Neyens🇧🇪 · Nele Vermeulen🇧🇪 · Henry Stroke🇺🇸

   The quadrupole moments of 29Mg and 33Mg have been constrained by collinear laser spectroscopy at CERN-ISOLDE. The values are consistent with shell-model predictions, thus supporting the current understanding of light nuclei associated with the "island of inversion".

   nucl-exHyperfine Interact.(2019)·5 citations
4. 04*

   Quasi-elastic polarization-transfer measurements on the deuteron in anti-parallel kinematics

   Sebouh J. Paul🇩🇪 · David Izraeli🇮🇱 · Tilen Brecelj🇸🇮 · Israel Yaron🇮🇱 · Patrick Achenbach🇩🇪 · Hartmuth Arenhövel🇩🇪 · Adi Ashkenazi🇺🇸 · Jure Beričič🇺🇸 · Ralph Böhm🇩🇪 · Damir Bosnar🇭🇷 · Ethan Cline🇺🇸 · Erez O. Cohen🇮🇱 and 32 other authors

   We present measurements of the polarization-transfer components in the ${}^2$H$(\vec{e},e^{\prime }\vec{p})$ reaction, covering a previously unexplored kinematic region with large positive (anti-parallel) missing momentum, $p_{\mathrm{miss}}$, up to 220 MeV$/c$, and $Q^2=0.65$ $(\mathrm{GeV}/c{)}^2$. These measurements, performed at the Mainz Microtron (MAMI), were motivated by theoretical calculations which predict small final-state interaction (FSI) effects in these kinematics, making them favorable for searching for medium modifications of bound nucleons in nuclei. We find in this kinematic region that the measured polarization-transfer components $P_x$ and $P_z$ and their ratio agree with the theoretical calculations, which use free-proton form factors. Using this, we establish upper limits on possible medium effects that modify the bound proton's form factor ratio $G_E/G_M$ at the level of a few percent. We also compare the measured polarization-transfer components and their ratio for ${}^2$H to those of a free (moving) proton. We find that the universal behavior of ${}^2$H, ${}^4$He and ${}^{12}$C in the double ratio $\frac{(P_x/P_z{)}^A}{(P_x/P_z{)}^{{}^1\mathrm{H}}}$ is maintained in the positive missing-momentum region.

   nucl-exPLB(2019)·6 citations
5. 05*

   Extracting free-space observables from trapped interacting clusters

   Xilin Zhang🇺🇸

   The energy spectrum of two short-range interacting particles in a harmonic potential trap has previously been related to free-space scattering phase shifts. But the existing formula for this purpose is exact only in the limit of an infinitely shallow trap. Here we provide a systematically improved formula---describing the low-energy dynamics---that enables the use of finite traps. This paves the way for extracting nuclear scattering phase shifts from {\it ab initio} nuclear many-body structure calculations, a long-sought goal in nuclear physics. The derivation establishes effective field theory as a powerful framework for studying the connection between structure information of a trapped system (with two or more sub-clusters) and continuum physics in the fields of both nuclear and condensed-matter physics.

   ↳ nucl-thcond-mat.quant-gasnucl-exPRC(2020)·31 citations
6. 06*

   Compton Scattering off Pions and Electromagnetic Polarizabilities

   Murray Moinester🇮🇱 · Stefan Scherer🇩🇪

   The electric (${\alpha }_{\pi }$) and magnetic (${\beta }_{\pi }$) Compton polarizabilities of both the charged and the neutral pion are of fundamental interest in the low-energy sector of quantum chromodynamics (QCD). Pion polarizabilities affect the shape of the $\gamma \pi \to \gamma \pi$ Compton scattering angular distribution at back scattering angles and $\gamma \gamma \to \pi \pi$ absolute cross sections. Theory derivations are given of the $\gamma \pi \to \gamma \pi$ Compton scattering differential cross section, dispersion relations, and sum rules in terms of the polarizabilities. We review experimental charged and neutral polarizability studies and theoretical predictions. The ${\pi }^0$ polarizabilities were deduced from DESY Crystal Ball $\gamma \gamma \to {\pi }^0{\pi }^0$ data, but with large uncertainties. The charged pion polarizabilities were deduced most recently from (1) radiative pion Primakoff scattering ${\pi }^{-}Z\to {\pi }^{-}Z\gamma$ at CERN COMPASS, (2) two-photon pion pair production $\gamma \gamma \to {\pi }^{+}{\pi }^{-}$ at SLAC Mark II, and (3) radiative pion photoproduction $\gamma p\to \gamma {\pi }^{+}n$ from the proton at MAMI in Mainz. A stringent test of chiral perturbation theory (ChPT) is possible based on comparisons of precision experimental charged pion polarizabilities with ChPT predictions. Only the CERN COMPASS charged pion polarizability measurement has acceptably small uncertainties. Its value ${\alpha }_{{\pi }^{\pm }}-{\beta }_{{\pi }^{\pm }}=(4.0\pm 1.8)\times 10^{-4}{\text{fm}}^3$ agrees well with the two-loop ChPT prediction ${\alpha }_{{\pi }^{\pm }}-{\beta }_{{\pi }^{\pm }}=(5.7\pm 1.0)\times 10^{-4}{\text{fm}}^3$, strengthening the identification of the pion with the Goldstone boson of chiral symmetry breaking in QCD.

   ↳ hep-phhep-exnucl-exnucl-thInt.J.Mod.Phys.A(2019)·24 citations
7. 07*

   Position sensitive resonant Schottky cavities for heavy ion storage rings

   D. Dmytriiev · M. S. Sanjari🇩🇪 · Yu. A. Litvinov🇩🇪 · Th. Stöhlker🇩🇪

   Studying the rapid neutron capture process (r-process) in stellar environments, that leads to the creation of elements heavier than 56-Fe, remains one of the fundamental questions of modern physics and therefore an active field of research within nuclear astrophysics. Exotic nuclides which participate in the r-process due to their low production yield and short half-life can be efficiently investigated in storage rings. In such facilities non-destructive methods of particle detection are often used for in-flight measurements based on frequency analysis. Due to the low signal level the detectors should be very sensitive and fast because of short lifetime of the particles. Resonant Schottky cavity pickups fulfill such requirement. Apart from their applications in the measurements of beam parameters, they can be used in non-destructive in-ring decay studies of radioactive ion beams. In addition, position sensitive Schottky pick-up cavities can enhance precision in the isochronous mass measurement technique. The goal of this work is to design such a position sensitive resonant Schottky cavity pickup based on theoretical calculations and simulations.

   ↳ physics.ins-detastro-ph.IMnucl-exphysics.acc-phNucl.Instrum.Meth.B(2020)·8 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.