Wed·Jun 9, 2021Wednesday·June 9, 2021

1. 01*

   Measurement and Modeling of Proton-Induced Reactions on Arsenic from 35 to 200 MeV

   Morgan B. Fox🇺🇸 · Andrew S. Voyles🇺🇸 · Jonathan T. Morrell🇺🇸 · Lee A. Bernstein🇺🇸 · Jon C. Batchelder🇺🇸 · Eva R. Birnbaum🇺🇸 · Cathy S. Cutler🇺🇸 · Arjan J. Koning🇦🇹 · Amanda M. Lewis🇺🇸 · Dmitri G. Medvedev🇺🇸 · Francois M. Nortier🇺🇸 · Ellen M. O'Brien🇺🇸 · Christiaan Vermeulen🇺🇸

   ${}^{72}$As is a promising positron emitter for diagnostic imaging that can be employed locally using a ${}^{72}$Se generator. However, current reaction pathways to ${}^{72}$Se have insufficient nuclear data for efficient production using regional 100-200 MeV high-intensity proton accelerators. In order to address this deficiency, stacked-target irradiations were performed at LBNL, LANL, and BNL to measure the production of the ${}^{72}$Se/${}^{72}$As PET generator system via ${}^{75}$As(p,x) between 35 and 200 MeV. This work provides the most well-characterized excitation function for ${}^{75}$As(p,4n)${}^{72}$Se starting from threshold. Additional focus was given to report the first measurements of ${}^{75}$As(p,x)${}^{68}$Ge and bolster an already robust production capability for the highly valuable ${}^{68}$Ge/${}^{68}$Ga PET generator. Thick target yield comparisons with prior established formation routes to both generators are made. In total, high-energy proton-induced cross sections are reported for 55 measured residual products from ${}^{75}$As, Cu, and Ti targets, where the latter two materials were present as monitor foils. These results were compared with literature data as well as the default theoretical calculations of the nuclear model codes TALYS, CoH, EMPIRE, and ALICE. Reaction modeling at these energies is typically unsatisfactory due to few prior published data and many interacting physics models. Therefore, a detailed assessment of the TALYS code was performed with simultaneous parameter adjustments applied according to a standardized procedure. Particular attention was paid to the formulation of the two-component exciton model in the transition between the compound and pre-equilibrium regions, with a linked investigation of level density models for nuclei off of stability and their impact on modeling predictive power.

   nucl-exnucl-thPRC(2021)·13 citations
2. 02*

   Optical calibration of the SNO+ detector in the water phase with deployed sources

   SNO+ Collaboration: M. R. Anderson🇨🇦 · S. Andringa🇵🇹 · M. Askins🇺🇸 · D. J. Auty🇨🇦 · F. Barão🇵🇹 · N. Barros🇵🇹 · R. Bayes🇨🇦 · E. W. Beier🇺🇸 · A. Bialek🇨🇦 · S. D. Biller🇬🇧 · E. Blucher🇺🇸 · M. Boulay🇨🇦 and 109 other authors

   SNO+ is a large-scale liquid scintillator experiment with the primary goal of searching for neutrinoless double beta decay, and is located approximately 2 km underground in SNOLAB, Sudbury, Canada. The detector acquired data for two years as a pure water Cherenkov detector, starting in May 2017. During this period, the optical properties of the detector were measured in situ using a deployed light diffusing sphere, with the goal of improving the detector model and the energy response systematic uncertainties. The measured parameters included the water attenuation coefficients, effective attenuation coefficients for the acrylic vessel, and the angular response of the photomultiplier tubes and their surrounding light concentrators, all across different wavelengths. The calibrated detector model was validated using a deployed tagged gamma source, which showed a 0.6% variation in energy scale across the primary target volume.

   ↳ physics.ins-dethep-exnucl-exJINST(2021)·23 citations
3. 03*

   Evolution of octupole deformation and collectivity in neutron-rich lanthanides

   K. Nomura🇭🇷 · R. Rodríguez-Guzmán🇰🇼 · L. M. Robledo🇪🇸 · J. E. García-Ramos · N. C. Hernández

   The onset of octupole deformation and its impact on related spectroscopic properties is studied in even-even neutron-rich lanthanide isotopes Xe, Ba, Ce, and Nd with neutron number $86⩽N⩽94$. Microscopic input comes from the Hartree-Fock-Bogoliubov approximation with constrains on the axially symmetric quadrupole and octupole operators using the Gogny-D1M interaction. At the mean-field level, reflection asymmetric ground states are predicted for isotopes with neutron number around $N=88$. Spectroscopic properties are studied by diagonalizing the interacting boson model Hamiltonian, with the parameters obtained via the mapping of the mean-field potential energy surface onto the expectation value of the Hamiltonian in the $s$, $d$, and $f$ boson condensate state. The results obtained for low-energy positive- and negative-parity excitation spectra as well as the electric dipole, quadrupole, and octupole transition probabilities indicate the onset of pronounced octupolarity for $Z\approx 56$ and $N\approx 88$ nuclei.

   ↳ nucl-thnucl-exPRC(2021)·34 citations
4. 04*

   ${}^{12}\mathbf{C}+{}^{12}\mathbf{C}$ Fusion ${\mathbf{S}}^{\ast }$-factor from a Full-microscopic Nuclear Model

   Yasutaka Taniguchi🇯🇵 · Masaaki Kimura🇯🇵

   The ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion reaction plays a vital role in the explosive phenomena of the universe. The resonances in the Gamow window rule its reaction rate and products. Hence, the determination of the resonance parameters by nuclear models is indispensable as the direct measurement is not feasible. Here, for the first time, we report the resonances in the ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}$ fusion reaction described by a full-microscopic nuclear model. The model plausibly reproduces the measured low-energy astrophysical $S$-factors and predicts the resonances in the Gamow window. Contradictory to the hindrance model, we conclude that there is no low-energy suppression of the $S$-factor.

   ↳ nucl-thnucl-exPLB(2021)·30 citations
5. 05*

   Ground State Properties of Charmed Hypernuclei with Mean Field Approach

   H. Güven🇫🇷 · K. Bozkurt🇫🇷 · E. Khan🇫🇷 · J. Margueron🇫🇷

   Closed shell charmed hypernuclei ${}_{{\Lambda }_c}^5$Li, ${}_{{\Lambda }_c}^{17}$F, ${}_{{\Lambda }_c}^{41}$Sc, ${}_{{\Lambda }_c}^{57}$Cu, ${}_{{\Lambda }_c}^{133}$Sb and ${}_{{\Lambda }_c}^{209}$Bi are calculated within Hartree-Fock approach by using three different force sets derived from microscopic Brueckner-Hartree-Fock calculations of $\Lambda$ hypernuclei. Ground state properties (binding energies, ${\Lambda }_c$ separation energies, ${\Lambda }_c$ single particle energies and ${\Lambda }_c$ densities) of charmed nuclei are examined. Due to the Coulomb repulsion between protons and the ${\Lambda }_c$ baryon, charmed hypernuclei are most bound for $16\le$A$\le 41$, where ${}_{{\Lambda }_c}^{17}$F can be considered as an excellent candidate to measure charmed hypernuclei. The competition between the attractive nucleon-${\Lambda }_c$ interaction and the Coulomb repulsion is discussed, and we compare $\Lambda$ and ${\Lambda }_c$ hypernuclei properties.

   ↳ nucl-thhep-phnucl-exPRC(2021)·5 citations
6. 06*

   The soft drop momentum sharing fraction $z_g$ beyond leading-logarithmic accuracy

   Pedro Cal🇳🇱 · Kyle Lee🇺🇸 · Felix Ringer🇺🇸 · Wouter J. Waalewijn🇳🇱

   Grooming techniques, such as soft drop, play a central role in reducing sensitivity of jets to e.g. underlying event and hadronization at current collider experiments. The momentum sharing fraction $z_g$, of the two branches in a jet that pass the soft drop condition, is one of the most important observables characterizing a collinear splitting inside the jet, and directly probes the QCD splitting functions. In this work, we present a factorization framework that enables a systematic calculation of the corresponding cross section beyond leading-logarithmic (LL) accuracy, showing that this measurement is not only sensitive to the QCD charge but also the spin of the parton that initiates the jet. Our results at next-to-leading logarithmic (NLL${}^{\prime }$) accuracy include non-global logarithms, and provide a first meaningful assessment of the perturbative uncertainty. We present a comparison to the available experimental data from ALICE, ATLAS, and STAR and find excellent agreement.

   ↳ hep-phhep-exnucl-exnucl-thPLB(2022)·29 citations
7. 07*

   Measurement of prompt D${}^0$, ${\Lambda }_c^{+}$, and ${\Sigma }_c^{0,++}$(2455) production in pp collisions at $\sqrt{s}=13$ TeV

   ALICE Collaboration

   The $p_{\mathrm{T}}$-differential production cross sections of prompt D${}^0$, ${\Lambda }_{\mathrm{c}}^{+}$, and ${\Sigma }_{\mathrm{c}}^{0,++}(2455)$ charmed hadrons are measured at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}=13$ TeV. This is the first measurement of ${\Sigma }_{\mathrm{c}}^{0,++}$ production in hadronic collisions. Assuming the same production yield for the three ${\Sigma }_{\mathrm{c}}^{0,+,++}$ isospin states, the baryon-to-meson cross section ratios ${\Sigma }_{\mathrm{c}}^{0,+,++}/{\mathrm{D}}^0$ and ${\Lambda }_{\mathrm{c}}^{+}/{\mathrm{D}}^0$ are calculated in the transverse momentum ($p_{\mathrm{T}}$) intervals $2<p_{\mathrm{T}}<12$ GeV/$c$ and $1<p_{\mathrm{T}}<24$ GeV/$c$. Values significantly larger than in e${}^{+}$e${}^{-}$ collisions are observed, indicating for the first time that baryon enhancement in hadronic collisions also extends to the ${\Sigma }_{\mathrm{c}}$. The feed-down contribution to ${\Lambda }_{\mathrm{c}}^{+}$ production from ${\Sigma }_{\mathrm{c}}^{0,+,++}$ is also reported and is found to be larger than in e${}^{+}$e${}^{-}$ collisions. The data are compared with predictions from event generators and other phenomenological models, providing a sensitive test of the different charm-hadronisation mechanisms implemented in the models.

   ↳ hep-exnucl-exPRL(2022)·116 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.