Fri·Jan 22, 2021Friday·January 22, 2021

1. 01*

   Photoneutron reactions on ${}^{\text{93}}$Nb at $E_{\gamma \text{max}}$=33-93 MeV

   A. N. Vodin (1)🇺🇦 · O. S. Deiev (1)🇺🇦 · V. Yu. Korda (2)🇺🇦 · I. S. Timchenko (1)🇺🇦 · S. N. Olejnik (1)🇺🇦 · N. I. Aizatsky (1)🇺🇦 · A. S. Kachan (1)🇺🇦 · L. P. Korda (1)🇺🇦 · E. L. Kuplennikov (1)🇺🇦 · V. A. Kushnir (1)🇺🇦 · V. V. Mitrochenko (1)🇺🇦 · S. A. Perezhogin (1) ((1) NSC Kharkov Institute of Physics and Technology, National Academy of Sciences of Ukraine, Kharkov, Ukraine, (2) Institute of Electrophysics and Radiation Technologies, National Academy of Sciences of Ukraine, Kharkov, Ukraine)🇺🇦

   The bremsstrahlung flux-averaged cross sections for the photoneutron reactions ${}^{\text{93}}$Nb($\gamma$,xn;x=1-5)${}^{\text{(93-x)m,g}}$Nb were measured in the range of boundary energies of bremsstrahlung $\gamma$-quanta $E_{\gamma \text{max}}$=33-93 MeV with a step $\Delta E_{\gamma \text{max}}\approx$ 2 MeV. The isomeric ratios of the average cross-sections of the products of the reactions ${}^{\text{93}}$Nb ($\gamma$ ,4n)${}^{\text{89m,g}}$Nb and ${}^{\text{93}}$Nb($\gamma$,5n)${}^{\text{88m,g}}$ Nb were determined in the energy ranges $E_{\gamma \text{max}}$ = 50-93 and 70-93 MeV, respectively. The experiments were carried out on the beam of the linear electron accelerator LU-40 of the Science and Research Establishment (SRE) "Accelerator" at National Science Center Kharkov Institute of Physics and Technology (NSC KIPT) using the method of induced activity. Calculations of the cross sections, average cross sections, and isomeric ratios of the reaction products were performed using the TALYS 1.9 code with default parameters and the GEANT4 code. The tendency of a more successful description of the average cross sections of photoneutron reactions with the formation of final odd-even Nb nuclei than odd-odd Nb nuclei is revealed. The experimental average cross sections for the reactions ($\gamma$,2n) and ($\gamma$,4n) are in good agreement with theory, while in the case of reactions ($\gamma$,n), ($\gamma$,3n), and ($\gamma$,5n), some discrepancies are observed. The results obtained for the reactions ($\gamma$,n), ($\gamma$,3n) and ($\gamma$,4n) are in satisfactory agreement with the known literature data. The average cross sections for the reactions ($\gamma$,2n) and ($\gamma$,5n) and the isomeric ratios of the reaction products ${}^{\text{93}}$Nb($\gamma$,5n)${}^{\text{88m,g}}$Nb were measured for the first time.

   nucl-exNPA(2021)·24 citations
2. 02*

   Lifetime Measurements in the Even-Even ${}^{102-108}$Cd Isotopes

   M. Siciliano🇫🇷 · J.J. Valiente-Dobón🇮🇹 · A. Goasduff🇮🇹 · T.R. Rodríguez🇪🇸 · D. Bazzacco🇮🇹 · G. Benzoni🇮🇹 · T. Braunroth🇩🇪 · N. Cieplicka-Oryńczak🇮🇹 · E. Clément🇫🇷 · F.C.L. Crespi · G. de France🇫🇷 · M. Doncel🇪🇸 and 25 other authors

   The heaviest N=Z doubly-magic nucleus, ${}^{100}$Sn, and the neighboring nuclei offer unique opportunities to investigate the properties of nuclear interaction in extreme conditions. In particular, the Cd isotopes are expected to present features similar to those found in the Sn isotopic chain, since they have only two proton holes in the Z=50 shell. In this manuscript, the lifetime measurements of low-lying states in the even-mass ${}^{102-108}$Cd is presented. Thanks to the powerful detection capabilities of AGATA array and VAMOS++ spectrometer, the unusual employment of multi-nucleon transfer reactions permitted to investigate the first 2${}^{+}$ and 4${}^{+}$ states in all these nuclei, together with various deformed bands in ${}^{106}$Cd. The results were interpreted in the context of new state-of-the-art beyond-mean-field calculations, using the symmetry-conserving configuration-mixing approach. Despite the similarities in the electromagnetic properties of the low-lying states, there is a fundamental structural difference between the ground-state bands in the Z=48 and Z=50 isotopes. The comparison between experimental and theoretical results revealed a rotational character of the Cd nuclei, which have prolate-deformed ground states with ${\beta }_2\approx 0.2$. At this deformation Z=48 becomes a closed-shell configuration, which is favored with respect to the spherical one.

   nucl-exPRC(2021)·21 citations
3. 03*

   On Mass and Matter

   Craig D. Roberts🇨🇳

   The visible Universe is largely characterised by a single mass-scale; namely, the proton mass, $m_p$. Contemporary theory suggests that $m_p$ emerges as a consequence of gluon self-interactions, which are a defining characteristic of quantum chromodynamics (QCD), the theory of strong interactions in the Standard Model. However, the proton is not elementary. Its mass appears as a corollary of other, more basic emergent phenomena latent in the QCD Lagrangian, e.g. generation of nuclear-size gluon and quark mass-scales, and a unique effective charge that may describe QCD interactions at all accessible momentum scales. These remarks are explained herein; and focusing on the distribution amplitudes and functions of $\pi$ and $K$ mesons, promising paths for their empirical verification are elucidated. Connected therewith, in anticipation that production of $J/\psi$-mesons using $\pi$ and $K$ beams can provide access to the gluon distributions in these pseudo-Nambu-Goldstone modes, predictions for all $\pi$ and $K$ distribution functions are provided at the scale $\zeta =m_{J/\psi }$.

   ↳ hep-phhep-exhep-latnucl-ex+1AAPPS Bull.(2021)·51 citations
4. 04*

   The design of the n2EDM experiment

   N. J. Ayres (1) · G. Ban (2) · L. Bienstman (3) · G. Bison (4) · K. Bodek (5) · V. Bondar (1) · T. Bouillaud (6) · E. Chanel (7) · J. Chen (2) · P.-J. Chiu (1,4) · B. Clément (6) · C. Crawford (8) and 49 other authors

   We present the design of a next-generation experiment, n2EDM, currently under construction at the ultracold neutron source at the Paul Scherrer Institute (PSI) with the aim of carrying out a high-precision search for an electric dipole moment of the neutron. The project builds on experience gained with the previous apparatus operated at PSI until 2017, and is expected to deliver an order of magnitude better sensitivity with provision for further substantial improvements. An overview is given of the experimental method and setup, the sensitivity requirements for the apparatus are derived, and its technical design is described.

   ↳ physics.ins-detnucl-exEPJC(2021)·92 citations
5. 05*

   Physics reach of a low threshold scintillating argon bubble chamber in coherent elastic neutrino-nucleus scattering reactor experiments

   L. J. Flores🇲🇽 · Eduardo Peinado🇲🇽 · E. Alfonso-Pita🇲🇽 · K. Allen🇺🇸 · M. Baker🇺🇸 · E. Behnke🇺🇸 · M. Bressler🇺🇸 · K. Clark🇨🇦 · R. Coppejans🇺🇸 · C. Cripe🇺🇸 · M. Crisler🇺🇸 · C. E. Dahl🇺🇸 and 22 other authors

   The physics reach of a low threshold (100 eV) scintillating argon bubble chamber sensitive to Coherent Elastic neutrino-Nucleus Scattering (CE$\nu$NS) from reactor neutrinos is studied. The sensitivity to the weak mixing angle, neutrino magnetic moment, and a light $Z^{\prime }$ gauge boson mediator are analyzed. A Monte Carlo simulation of the backgrounds is performed to assess their contribution to the signal. The analysis shows that world-leading sensitivities are achieved with a one-year exposure for a 10 kg chamber at 3 m from a 1 MW${}_{th}$ research reactor or a 100 kg chamber at 30 m from a 2000 MW${}_{th}$ power reactor. Such a detector has the potential to become the leading technology to study CE$\nu$NS using nuclear reactors.

   ↳ hep-exhep-phnucl-exphysics.ins-detPRD(2021)·59 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.