Mon·Jun 15, 2020Monday·June 15, 2020

1. 01*

   High spin states of ${}^{204}$At: isomeric states and shears band structure

   D. Kanjilal · S. K. Dey · S. S. Bhattacharjee · A. Bisoi · M. Das · C. C. Dey · S. Nag · R. Palit · S. Ray · S. Saha · J. Sethi · S. Saha

   High-spin states of neutron deficient Trans-Lead nucleus ${}^{204}$At were populated up to $\sim 8\mathrm{MeV}$ excitation through the ${}^{12}$C + ${}^{197}$Au fusion evaporation reaction. Decay of the associated levels through prompt and delayed $\gamma$-ray emissions were studied to evaluate the underlying nuclear structure. The level scheme, which was partly known, was extended further. An isomeric $16^{+}$ level with observed lifetime $\tau =52\pm 5\mathrm{ns}$, was established from our measurements. Attempts were made to interpret the excited states based on multi quasiparticle and hole structures involving $2f_{5/2}$, $1h_{9/2}$, and $1i_{13/2}$ shell model states, along with moderate core excitation. Magnetic dipole band structure over the spin parity range:~$16^{+}-23^{+}$ was confirmed and evaluated in more detail, including the missing cross-over $E2$ transitions. Band-crossing along the shears band was observed and compared with the evidence of similar phenomena in the neighbouring neutron deficient ${}^{202}$Bi, ${}^{205}$Rn isotones and the ${}^{203}$At isotope. Based on comparison of the measured $B(M1)/B(E2)$ values for transitions along the band with the semiclassical model based estimates, the shears band of ${}^{204}$At was established along with the level scheme.

   nucl-exEPJA(2022)·5 citations
2. 02*

   QCD2019 Workshop Summary

   S.J. Brodsky🇺🇸 · V.D. Burkert🇺🇸 · D.S. Carman🇺🇸 · J.P. Chen🇺🇸 · Z.-F. Cui🇨🇳 · M. Döring🇺🇸 · H.G. Dosch🇩🇪 · J.P. Draayer🇺🇸 · L. Elouadrhiri🇺🇸 · D.I. Glazier🇬🇧 · A.N. Hiller Blin🇺🇸 · T. Horn🇺🇸 and 17 other authors

   The topical workshop {\it Strong QCD from Hadron Structure Experiments} took place at Jefferson Lab from Nov. 6-9, 2019. Impressive progress in relating hadron structure observables to the strong QCD mechanisms has been achieved from the {\it ab initio} QCD description of hadron structure in a diverse array of methods in order to expose emergent phenomena via quasi-particle formation. The wealth of experimental data and the advances in hadron structure theory make it possible to gain insight into strong interaction dynamics in the regime of large quark-gluon coupling (the strong QCD regime), which will address the most challenging problems of the Standard Model on the nature of the dominant part of hadron mass, quark-gluon confinement, and the emergence of the ground and excited state hadrons, as well as atomic nuclei, from QCD. This workshop aimed to develop plans and to facilitate the future synergistic efforts between experimentalists, phenomenologists, and theorists working on studies of hadron spectroscopy and structure with the goal to connect the properties of hadrons and atomic nuclei available from data to the strong QCD dynamics underlying their emergence from QCD. These results pave the way for a future breakthrough extension in the studies of QCD with an Electron-Ion Collider in the U.S.

   ↳ hep-phhep-latnucl-exnucl-thIJMPE(2020)·76 citations
3. 03*

   Constraining gluon density of pions at large $x$ by pion-induced $J/\psi$ production

   Wen-Chen Chang🇹🇼 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇯🇵

   The gluon distributions of the pion obtained from various global fits exhibit large variations among them. Within the framework of the color evaporation model, we show that the existing pion-induced $J/\psi$ production data, usually not included in the global fits, can impose useful additional constraints on the pion parton distribution functions (PDFs). In particular, these data can probe the pion's gluon densities at large $x$. Existing pion-induced $J/\psi$ data covering a broad range of beam momenta are compared with next-to-leading-order QCD calculations using various sets of pion PDFs. It is found that $J/\psi$ data measured at forward rapidity and at sufficiently high beam momentum are sensitive to the large-$x$ gluon distribution of pions. The current $J/\psi$ data favor the Sutton-Martin-Roberts-Stirling and Gluck-Reya-Vogt pion PDFs, containing significant gluon content at large $x$.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·41 citations
4. 04*

   Efficient determination of HPGe {\gamma}-ray efficiencies at high energies with ready-to-use simulation software

   Jan Mayer🇩🇪 · Elena Hoemann · Markus Müllenmeister · Philipp Scholz · Andreas Zilges🇩🇪

   The full-energy-peak efficiency of HPGe detectors at $\gamma$-ray energies around 10 MeV is not easily accessible with experimental methods. Monte-Carlo simulations with Geant4 can provide these efficiencies. G4Horus is a ready-to-use Geant4 application for the HORUS HPGe-detector array. Users can configure the modular parts to match their experiment with minimal knowledge of the simulation software and limited time commitment. In our case, knowing and implementing the geometry with high precision is the biggest challenge. To implement the different target chambers, we transform the existing CAD models to Geant4 geometry with CADMesh. We also found a large discrepancy between experimental and simulated efficiency for some older HPGe detectors, which could be remedied by introducing a large dead region around the inner core. This project is open source and available from https://github.com/janmayer/G4Horus We invite everyone to adapt the project or adopt parts of the code for other projects.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2020)·5 citations
5. 05*

   Design and Implementation of Detector Control System for Muon Forward Tracker at ALICE

   K. Yamakawa🇯🇵 · A. Augustinus🇨🇭 · G. Batigne🇫🇷 · P. Chochula🇨🇭 · M. Oya🇯🇵 · S. Panebianco🇫🇷 · O. Pinazza🇨🇭 · K. Shigaki🇯🇵 · R. Tieulent🇫🇷 · Y. Yamaguchi🇯🇵

   ALICE is the experiment at the CERN LHC devoted to study heavy-ion collisions. An upgrade program of the ALICE detector is ongoing toward the LHC Run 3 starting in 2022 together with the upgrade of the data acquisition system and the detector control system (DCS). One of the main projects of the current ALICE upgrade program is the addition of the muon forward tracker (MFT), a new silicon pixel detector located at forward rapidity. In this paper, we describe the DCS of the MFT detector which is entirely controlled via a finite state machine in a hierarchical system.

   ↳ physics.ins-detnucl-exJINST(2020)·1 citation
6. 06*

   Sensitivity of the NEXT experiment to Xe-124 double electron capture

   G. Martínez-Lema🇪🇸 · M. Martínez-Vara🇪🇸 · M. Sorel🇪🇸 · C. Adams🇺🇸 · V. Alvarez🇪🇸 · L. Arazi🇮🇱 · I.J. Arnquist🇺🇸 · C.D.R Azevedo🇵🇹 · K. Bailey🇺🇸 · F. Ballester🇪🇸 · J.M. Benlloch-Rodríguez🇪🇸 · F.I.G.M. Borges🇵🇹 and 79 other authors

   Double electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture ($2\nu ECEC$) has been predicted for a number of isotopes, but only observed in ${}^{78}$Kr, ${}^{130}$Ba and, recently, ${}^{124}$Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, $0\nu ECEC$. Here we report on the current sensitivity of the NEXT-White detector to ${}^{124}$Xe $2\nu ECEC$ and on the extrapolation to NEXT-100. Using simulated data for the $2\nu ECEC$ signal and real data from NEXT-White operated with ${}^{124}$Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of ${}^{124}$Xe and for a 5-year run, a sensitivity to the $2\nu ECEC$ half-life of $6\times 10^{22}$ y (at 90% confidence level) or better can be reached.

   ↳ hep-exnucl-exphysics.ins-detJHEP(2020)·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.