Tue·Mar 19, 2024Tuesday·March 19, 2024

1. 01*

   Evolution of chirality from transverse wobbling in ${}^{135}$Pr

   N. Sensharma🇺🇸 · U. Garg🇺🇸 · Q. B. Chen🇨🇳 · S. Frauendorf · S. Zhu🇨🇳 · J. Arroyo · A. D. Ayangeakaa🇺🇸 · D. P. Burdette🇺🇸 · M. P. Carpenter🇺🇸 · P. Copp · J. L. Cozzi · S. S. Ghugre🇮🇳 and 11 other authors

   Chirality is a distinct signature that characterizes triaxial shapes in nuclei. We report the first observation of chirality in the nucleus ${}^{135}$Pr using a high-statistics Gammasphere experiment with the ${}^{123}$Sb(${}^{16}$O,4n)${}^{135}$Pr reaction. Two chiral-partner bands with the configuration $\pi (1h_{11/2}{)}^1\otimes \nu (1h_{11/2}{)}^{-2}$ have been identified in this nucleus. Angular distribution analyses of the $\Delta I=1$ transitions connecting the two bands reveal a dominant dipole character, and quasiparticle triaxial rotor model calculations show good agreement with the data. Since the simultaneous observation of chirality and transverse wobbling in ${}^{135}$Pr relies critically on these angular distribution results, we also address and refute the experimental and theoretical criticisms raised in a recent work by Lv et al., presenting additional evidence that further strengthens our interpretation. This marks the first observation of both hallmarks of triaxiality-chirality and wobbling-in the same nucleus.

   nucl-exnucl-thPRC(2026)·2 citations
2. 02*

   Revisiting the excitation of the low-lying ${}^{181\text{m}}$Ta isomer in optical laser-generated plasma

   Simone Gargiulo · Ivan Madan · Benoit Truc · Paolo Usai · Kjeld Beeks🇨🇭 · Veronica Leccese · Giovanni Maria Vanacore · Fabrizio Carbone

   The excitation of the ${}^{181\text{m}}$Ta isomer in the laser-plasma scenario was claimed to have been observed more than two decades ago. However, the reported experimental findings - and the respective high excitation rate - were later questioned as they could not be reproduced theoretically. The controversy has remained open ever since. In this work, we reinvestigate both theoretically and experimentally the ${}^{181\text{m}}$Ta nuclear excitation in an optical laser-generated plasma. Experimentally we have found no evidence for such an excitation process as consistently predicted by previous and our theoretical models.

   nucl-exnucl-thPRL(2024)·4 citations
3. 03*

   Photoneutron cross section measurements on ${}^{208}$Pb in the Giant Dipole Resonance region

   I. Gheorghe · S. Goriely🇧🇪 · N. Wagner · T. Aumann🇩🇪 · M. Baumann · P. van Beek · P. Kuchenbrod · H. Scheit🇩🇪 · D. Symochko🇩🇪 · T. Ari-izumi · F.L. Bello Garrote🇳🇴 · T. Eriksen🇳🇴 and 7 other authors

   Photoneutron reactions on ${}^{208}$Pb in the Giant Dipole Resonance energy region have been investigated at the $\gamma$-ray beam line of the NewSUBARU facility in Japan. The measurements made use of quasi-monochromatic laser Compton backscattering $\gamma$-ray beams in a broad energy range, from the neutron threshold up to 38 MeV, and of a flat-efficiency moderated ${}^3$He neutron detection system along with associated neutron-multiplicity sorting methods. We report absolute cross sections and mean photoneutron energies for the ${}^{208}$Pb$(\gamma ,inX)$ reactions with $i$~=~1 to 4. The fine structure present in the ${}^{208}$Pb$(\gamma ,n)$ cross sections at incident energies lower than 13~MeV has been observed. The photoabsorption cross section has been obtained as the sum of the $(\gamma ,inX)$ reaction cross sections. By reproducing the measured ring-ratio values at excitation energies below the two neutron separation energy, we were able to extract estimations on the ${}^{208}$Pb$(\gamma ,n)$ photoneutron energy spectra and on the partial photoneutron cross sections for leaving the residual ${}^{207}$Pb in its ground and first two excited states. The present results are compared with data from the literature and statistical model calculations.

   nucl-exPRC(2024)·11 citations
4. 04*

   New insights on fission of ${}^{235}$U induced by high energy neutrons from a new measurement at CERN n\_TOF

   Alice Manna · Elisa Pirovano · the n\_TOF Collaboration

   The ${}^{235}$U(n,f) reaction cross section was measured relative to neutron-proton elastic scattering for the first time in the energy region from 10 MeV to 440 MeV at the CERN n\_TOF facility, extending the upper limit of the only previous measurement in the literature by more than 200 MeV. Two independent detection systems were used simultaneously to extract the fission cross section. For neutron energies below 200 MeV, the present results agree within one standard deviation with the data available in literature and are well reproduced by the IAEA evaluation. Above 200 MeV, the comparison of model calculations to the present data indicates the need to introduce a transient time in the description of the neutron-induced fission process in order to allow the simultaneous description of (n,f) and (p,f) reactions.

   nucl-exPLB(2025)·4 citations
5. 05*

   Systematic shell-model study of structure and isomeric states in ${}^{204-213}$Bi isotopes

   Sakshi Shukla🇮🇳 · Praveen C. Srivastava🇮🇳 · Deepak Patel🇮🇳

   In this work, we have performed systematic shell-model calculations for Bi isotopes with $A=$ 204-213 using KHH7B and KHM3Y effective interactions. We have reported yrast and non-yrast shell-model states corresponding to the available experimental data. From the comparison with the experimental data, we could assign spin and parity of several unconfirmed states. We have also calculated electromagnetic properties and compared them with the available experimental data and predicted where experimental data are not available. This study also includes a detailed discussion of multiple isomeric states based on computed shell-model configurations and their respective half-lives.

   ↳ nucl-thnucl-exJ.Phys.G(2024)·4 citations
6. 06*

   Development of neutron beamline for laser-driven neutron resonance spectroscopy

   Zechen Lan · Yasunobu Arikawa · Alessio Morace · Yuki Abe🇯🇵 · S. Reza Mirfayzi🇬🇧 · Tianyun Wei · Takehito Hayakawa🇯🇵 · Akifumi Yogo

   Recent progress of laser science provides laser-driven neutron source (LDNS), which has remarkable features such as the short pulse width. One of the key techniques to be developed for more efficient use of the LDNS is neutron collimation tubes to increase the number of neutrons arriving at a detector in the time-of-flight method. However, when a tube with a thick wall is used as a collimator the neutron collection efficiency at the detector increases but the time resolution becomes wider because of multiple scattering inside of the tube. In the present study, we have developed a collimation tube made of Ni-0, which is optimized for the increased neutron collection efficiency and a reasonable time resolution. This collimator has been demonstrated experimentally using neutron resonance spectroscopy with neutrons provided from LFEX laser.

   ↳ physics.ins-dethep-exnucl-exphysics.plasm-ph0 citations
7. 07*

   Mixed Species Charge and Baryon Balance Functions Studies with PYTHIA

   Claude Pruneau🇺🇸 · Sumit Basu🇸🇪 · Victor Gonzalez🇺🇸 · Brian Hanley🇺🇸 · Ana Marin🇩🇪 · Alexandru F. Dobrin🇷🇴 · Alexandru Manea🇷🇴

   Mixed species charge and baryon balance functions are computed based on proton--proton (pp) collisions simulated with the PYTHIA8 model. Simulations are performed with selected values of the collision energy $\sqrt{s}$ and the Monash tune and the Ropes and Shoving modes of PYTHIA8 to explore whether such measurements provide useful new information and constraints on mechanisms of particle production in pp collisions. Charge balance functions are studied based on mixed pairs of pions, kaons, and protons, whereas baryon balance functions are computed for mixed low mass strange and non-strange baryons. Both charge and baryon balance functions of mixed particle pairs feature shapes and amplitudes that sensitively depend on the particle considered owing largely to the particle production mechanisms implemented in PYTHIA. The evolution of balance functions integrals with the longitudinal width of the acceptance are presented and one finds that sums of such integrals for a given reference particle obey expected sum rules for both charge and baryon balance functions. Additionally, both types of balance functions are found to evolve in shape and amplitude with increasing collision energy $\sqrt{s}$ and the PYTHIA tunes considered.

   ↳ hep-phhep-exnucl-exnucl-thPRC(2024)·4 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.