Wed·Mar 17, 2021Wednesday·March 17, 2021

1. 01*

   Direct measurement of the mass difference of ${}^{72}$As-${}^{72}$Ge rules out ${}^{72}$As as a promising $\beta$-decay candidate to determine the neutrino mass

   Z. Ge🇫🇮 · T. Eronen🇫🇮 · A. de Roubin🇫🇷 · D. A. Nesterenko🇫🇮 · M. Hukkanen🇫🇮 · O. Beliuskina🇫🇮 · R. de Groote🇫🇮 · S. Geldhof🇫🇮 · W. Gins🇫🇮 · A. Kankainen🇫🇮 · Á. Koszorús🇬🇧 · J. Kotila🇫🇮 and 9 other authors

   We report the first direct determination of the ground-state to ground-state electron-capture $Q$-value for the ${}^{72}$As to ${}^{72}$Ge decay by measuring their atomic mass difference utilizing the double Penning trap mass spectrometer, JYFLTRAP. The $Q$-value was measured to be 4343.596(75)~keV, which is more than a 50-fold improvement in precision compared to the value in the most recent Atomic Mass Evaluation 2020. Furthermore, the new $Q$-value was found to be 12.4(40)~keV (3.1 $\sigma$) lower. With the significant reduction of the uncertainty of the ground-state to ground-state $Q$-value value combined with the level scheme of ${}^{72}$Ge from $\gamma$-ray spectroscopy, we confirm that the five potential ultra-low $Q$-value ${\beta }^{+}$-decay or electron capture transitions are energetically forbidden, thus precluding all the transitions as possible candidates for the electron neutrino mass determination. However, the discovery of small negative $Q$-values opens up the possibility to use ${}^{72}$As for the study of virtual $\beta$-$\gamma$ transitions.

   nucl-exPRC(2021)·21 citations
2. 02*

   First observation of a nuclear $s$-state of $\Xi$ hypernucleus, ${}_{\Xi }^{15}\mathrm{C}$

   M. Yoshimoto🇯🇵 · J. K. Ahn🇰🇷 · B. Bassalleck🇺🇸 · H. Ekawa🇯🇵 · Y. Endo🇯🇵 · M. Fujita🇯🇵 · Y. Han🇨🇳 · T. Hashimoto🇯🇵 · S. H. Hayakawa🇯🇵 · K. Hicks🇺🇸 · K. Hoshino🇯🇵 · S. Hoshino🇯🇵 and 37 other authors

   Bound-systems of ${\Xi }^{-}$--${}_{}^{14}\mathrm{N}$ are studied via ${\Xi }^{-}$ capture at rest followed by emission of a twin single-$\Lambda$ hypernucleus in the emulsion detectors. Two events forming extremely deep ${\Xi }^{-}$ bound states were obtained by analysis of a hybrid method in the E07 experiment at J-PARC and reanalysis of the E373 experiment at KEK-PS. The decay mode of one event was assigned as ${\Xi }^{-}{+}_{}^{14}\mathrm{N}{\to }_{\Lambda }^5\mathrm{He}$+${}_{\Lambda }^5\mathrm{He}$+${}_{}^4\mathrm{He}$+n. Since there are no excited states for daughter particles, the binding energy of the ${\Xi }^{-}$ hyperon, $B_{{\Xi }^{-}}$, in ${}_{}^{14}\mathrm{N}$ nucleus was uniquely determined to be 6.27 $\pm$ 0.27 MeV. Another ${\Xi }^{-}$--${}_{}^{14}\mathrm{N}$ system via the decay ${}_{\Lambda }^9\mathrm{Be}$ + ${}_{\Lambda }^5\mathrm{He}$ + n brings a $B_{{\Xi }^{-}}$ value, 8.00 $\pm$ 0.77 MeV or 4.96 $\pm$ 0.77 MeV, where the two possible values of $B_{{\Xi }^{-}}$ correspond to the ground and the excited states of the daughter ${}_{\Lambda }^9\mathrm{Be}$ nucleus, respectively. Because the $B_{{\Xi }^{-}}$ values are larger than those of the previously reported events (KISO and IBUKI), which are both interpreted as the nuclear $1p$ state of the ${\Xi }^{-}$--${}_{}^{14}\mathrm{N}$ system, these new events give the first indication of the nuclear $1s$ state of the $\Xi$ hypernucleus, ${}_{\Xi }^{15}\mathrm{C}$.

   nucl-exnucl-thphysics.ins-detPTEP(2021)·58 citations
3. 03*

   Investigating Globular Cluster Elemental Abundance Anomalies Using ${(}^3\text{He},d)$ Proton Transfer Reactions

   Caleb Marshall🇺🇸

   Globular clusters are dense aggregates of stars that evolve in relative isolation. For the better part of $40$ years these clusters have been known to possess unique chemical signatures called abundance anomalies. Recent observations have found these abundance anomalies to be the result of distinct stellar populations with the youngest population undergoing an unknown enrichment process. Understanding these chemical signatures requires a precise understanding of the thermonuclear reaction rates at relatively low temperatures. At these low temperatures reaction rates suffer from large uncertainties arising from poorly understood resonances in several key reactions. Transfer reactions provide key constrains on nuclear inputs for these resonances. This thesis presents an updated understanding of the sodium and potassium destroying reactions ${}^{23}$Na$(p,\gamma )$ and ${}^{39}$K$(p,\gamma )$, respectively. A reevaluated rate for ${}^{39}$K$(p,\gamma )$ indicates that it is less precisely known than previously thought, and future experimental study is needed to reduce its impact on globular cluster nucleosynthesis. Novel Bayesian techniques assess the uncertainties arising from transfer measurements. These techniques are applied to the transfer reaction ${}^{23}$Na${(}^3\text{He},d)$, which was carried out at Triangle Universities Nuclear Laboratory. Results of this experiment indicate that the energy of an important resonance in ${}^{23}$Na$(p,\gamma )$ is much lower than previously thought at $E_r=132(3)$ keV. The transfer measurement also indicates tension between previous direct studies of the resonance strength and the current transfer measurement. The impact of these uncertainties on the ${}^{23}$Na$(p,\gamma )$ reaction rate is investigated, and it is shown that this rate requires more intensive study to provide the precision needed to constrain nucleosynthesis in globular clusters.

   nucl-ex1 citation
4. 04*

   Inclusive photon production at forward rapidities using PMD in p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV with ALICE

   Mohammad Asif Bhat (for the ALICE Collaboration)🇮🇳

   We report on the performance studies of two correction methods, namely the efficiency-purity method and the Bayesian unfolding method applied to the pseudorapidity distribution of photons. The pseudorapidity distribution of inclusive photons at forward rapidities in the range \mbox{\small $(2.3<\eta <3.9)$} in p\textendash Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV is obtained with the HIJING Monte Carlo event generator. The simulated data samples were obtained from the Photon Multiplicity Detector (PMD) in ALICE.

   nucl-exhep-exSpringer Proc.Phys.(2022)·1 citation
5. 05*

   Mapping of the magnetic field to correct systematic effects in a neutron electric dipole moment experiment

   C. Abel🇬🇧 · N. J. Ayres🇨🇭 · G. Ban🇫🇷 · G. Bison🇨🇭 · K. Bodek🇵🇱 · V. Bondar🇨🇭 · E. Chanel🇨🇭 · P.-J. Chiu🇨🇭 · B. Clément🇫🇷 · C. B. Crawford🇺🇸 · M. Daum🇨🇭 · S. Emmenegger🇨🇭 and 41 other authors

   Experiments dedicated to the measurement of the electric dipole moment of the neutron require outstanding control of the magnetic field uniformity. The neutron electric dipole moment (nEDM) experiment at the Paul Scherrer Institute uses a 199Hg co-magnetometer to precisely monitor magnetic field variations. This co-magnetometer, in the presence of field non-uniformity, is responsible for the largest systematic effect of this measurement. To evaluate and correct that effect, offline measurements of the field non-uniformity were performed during mapping campaigns in 2013, 2014 and 2017. We present the results of these campaigns, and the improvement the correction of this effect brings to the neutron electric dipole moment measurement.

   ↳ physics.ins-dethep-exnucl-exPRA(2022)·9 citations
6. 06*

   Upgrade of Hardware Controls for the STAR Experiment at RHIC

   Jaroslav Adam🇺🇸 · Michael G. Cherney🇺🇸 · Joey D'Alesio🇺🇸 · Emma Dufresne🇺🇸 · Lukáš Holub🇨🇿 · Janet E. Seger🇺🇸 · David Tlustý🇺🇸

   The STAR experiment has been delivering significant physics results for more than 20 years. Stable operation of the experiment was achieved by using a robust controls system based on the Experimental Physics and Industrial Control System (EPICS). Now an object-oriented approach with Python libraries, adapted for EPICS software, is going to replace the procedural-based EPICS C libraries previously used at STAR. Advantages of the new approach include stability of operation, code reduction and straightforward project documentation. The first two sections of this paper introduce the STAR experiment, give an overview of the EPICS architecture, and present the use of Python for controls software. Specific examples, as well as upgrades of user interfaces, are outlined in the following sections.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2021)·2 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.