Mon·Dec 11, 2023Monday·December 11, 2023

1. 01*

   Measurement of yields and angular distributions of $\gamma$-quanta from the interaction of $14.1$ MeV neutrons with oxygen, phosphorus and sulfur

   D.N. Grozdanov · N.A. Fedorov🇷🇺 · S.B. Dabylova · Yu.N. Kopatch · I.N. Ruskov · V.R. Skoy · T.Yu. Tretyakova · C. Hramco · P.I. Kharlamov · G.V. Pampushik · P.G. Filonchik · A.V. Andreev🇷🇺

   A study of the inelastic scattering of neutrons with an energy of $14.1$~MeV on the nuclei of oxygen, phosphorus and sulfur was carried out at the TANGRA facility at JINR (Dubna). The purpose of the experiment was to refine existing and obtain new data on the yields and angular distributions of $\gamma$-quanta emitted by the studied nuclei as a result of neutron-induced nuclear reactions using the tagged neutron method. Two types of detector systems were used to register $\gamma$-quanta. The $\gamma$-ray yields were measured using a high-purity germanium (HPGe) detector. The angular distributions of $\gamma$-rays were obtained using a system of 18 scintillation detectors based on bismuth germanite Bi${}_4$Ge${}_3$O${}_{12}$ (BGO) located around the sample. As a result of the studies carried out, the yields of two transitions for the reaction of tagged neutrons with ${}^{16}$O, nine transitions for the reaction with ${}^{31}$P, and nine transitions for the reaction with ${}^{32}$S were measured for the first time. The angular anisotropy of the $\gamma$-radiation accompanying the inelastic scattering of neutrons with an energy of $14.1$~MeV on ${}^{31}$P nuclei was also measured for the first time.

   nucl-exnucl-thCPC(2024)·6 citations
2. 02*

   Understanding oscillating features of the timelike nucleon electromagnetic form factors within the extending vector meson dominance model

   Bing Yan🇨🇳 · Cheng Chen🇨🇳 · Xia Li🇨🇳 · Ju-Jun Xie🇨🇳

   We investigate the nonmonotonic behavior observed in the time-like nucleon electromagnetic form factors. Using a phenomenological extending vector meson dominance model, where the ground states $\rho$ and $\omega$ and their excited states $\rho (2D)$, $\omega (3D)$, and $\omega (5S)$ are taken into account, we have successfully reproduced the cross sections of $e^{+}{e}^{-}\to p\bar{p}$ and $e^{+}{e}^{-}\to n\bar{n}$ reactions. Furthermore, we have derived the nucleon electromagnetic form factors in the time-like region, and it is found that the so-called periodic behaviour of the nucleon effective form factors is not confirmed. However, there are indeed nonmonotonic structures in the line shape of nucleon effective form factors, which can be naturally reproduced by considering the contributions from the low-lying excited vector states.

   ↳ nucl-thhep-exhep-phnucl-exPRD(2024)·12 citations
3. 03*

   Improved description of nuclear charge radii: Global trends beyond $N=28$ shell closure

   Rong An🇨🇳 · Xiang Jiang🇺🇸 · Na Tang · Li-Gang Cao · Feng-Shou Zhang🇨🇳

   Charge radii measured with high accuracy provide a stringent benchmark for characterizing nuclear structure phenomena. In this work, the systematic evolution of charge radii for nuclei with $Z=19$-$29$ is investigated through relativistic mean field theory with effective forces NL3, PK1, and NL3${}^{\ast }$. The neutron-proton ($np$) correlation around Fermi surface originated from the unpaired neutron and proton has been taken into account tentatively in order to reduce the overestimated odd-even staggering of charge radii. This improved method can give an available description of charge radii across $N=28$ shell closure. A remarkable observation is that the charge radii beyond $N=28$ shell closure follow the similarly steep increasing trend, namely irrespective of the number of protons in the nucleus. Especially, the latest results of charge radii for nickel and copper isotopes can be reproduced remarkably well. Along $N=28$ isotonic chain, the sudden increase of charge radii is weakened across $Z=20$, but presented evidently across $Z=28$ closed shell. The abrupt changes of charge radii across $Z=22$ are also shown along $N=32$ and $34$ isotones, but the latter with a less slope. This seems to provide a sensitive indicator to identify the new magicity of a nucleus with universal trend of charge radii.

   ↳ nucl-thnucl-exPRC(2024)·17 citations
4. 04*

   Role of initial transverse momentum in a hybrid approach

   Niklas Götz🇩🇪 · Lucas Constantin🇩🇪 · Hannah Elfner🇩🇪

   The purpose of this work is to study the effect of exchanging initial condition models in a modular hybrid approach. The focus lies on the event-by-event correlations of elliptic and triangular flow. This study is performed in the hybrid approach SMASH-vHLLE, composed of the hadronic transport approach SMASH and the (3+1)d viscous hydrodynamic code vHLLE. The initial condition models investigated are SMASH IC, Trento and IP-Glasma. Correlations are calculated on an event-by-event basis between the eccentricities and momentum anisotropies of the initial state as well as the momentum anisotropies in the final state, both for ultra-central and off-central collisions for AuAu collisions at $\sqrt{s_{NN}}=200$ GeV. This work demonstrates that, although averaged values for the eccentricities of these models are very similar, substantial differences exist both in the distributions of eccentricities, the correlations amongst the initial state properties as well as in the correlations between initial state and final state properties. Notably, whereas initial state momentum anisotropy is shown to not affect the final state flow, the presence of radial flow affects the emergence of final state momentum anisotropies. Inclusion of radial flow in the linear fit improves the prediction of final state flow from initial state properties. The presence of momentum in the initial state has an effect on the emergence of flow and is therefore a relevant part of initial state models, challenging the common understanding of final state momentum anisotropies being a linear response to initial state eccentricity only.

   ↳ nucl-thhep-phnucl-exPRC(2024)·5 citations
5. 05*

   First Detailed Study of the Quantum Decoherence of Entangled Gamma Photons

   Julien Bordes · James R. Brown · Daniel P. Watts · Mikail Bashkanov · Ruth Newton · Nicholas Zachariou

   Constraints on the quantum decoherence of entangled $\gamma$ quanta at the mega-electron-volt scale, such as those produced following positron annihilation, have remained elusive for many decades. We present the first statistically and kinematically precise experimental data for triple Compton scattering of such entangled $\gamma$. An entanglement witness ($R$), relating to the enhancement of the azimuthal correlation between the final scattering planes, is obtained where one of the $\gamma$ underwent intermediate Compton scattering. The measured $R$, deconvolved from multiple scattering backgrounds, are found to exceed the classical limit for intermediate scatter angles up to $\sim$60${}^{\circ }$ and diminish at larger angles. The data are consistent with predictions from a first quantum theory of entangled triple Compton scattering as well as a simple model based approach. The results are crucial to future study and utilisation of entangled mega-electron-volt $\gamma$ in fundamental physics and PET imaging.

   ↳ quant-phnucl-exPRL(2024)·14 citations
6. 06*

   Long-range near-side correlation in $e^{+}{e}^{-}$ Collisions at 183-209 GeV with ALEPH Archived Data

   Yu-Chen Chen (1)🇺🇸 · Yi Chen (1)🇺🇸 · Anthony Badea (2)🇺🇸 · Austin Baty (3)🇺🇸 · Gian Michele Innocenti (4)🇨🇭 · Marcello Maggi (5)🇮🇹 · Christopher McGinn (1)🇺🇸 · Michael Peters (1)🇺🇸 · Tzu-An Sheng (1)🇺🇸 · Jesse Thaler (1)🇺🇸 · Yen-Jie Lee (1) ((1) Massachusetts Institute of Technology, Cambridge, Massachusetts, USA, (2) University of Chicago, Chicago, Illinois, USA, (3) University Illinois Chicago, Chicago, Illinois, USA, (4) CERN, Geneva, Switzerland, (5) INFN Sezione di Bari, Bari, Italy)🇺🇸

   The first measurement of two-particle angular correlations for charged particles with LEP-II data is presented. The study is performed using archived hadronic $e^{+}{e}^{-}$ data collected by ALEPH at center-of-mass energies up to 209 GeV, above the $W^{+}{W}^{-}$ production threshold, which provide access to unprecedented charged-particle multiplicities and more complex color-string configurations if compared to previous measurements at LEP-I energies. An intriguing long-range near-side excess is observed in the correlation function measured with respect to the thrust axis in the highest multiplicity interval $N_{\mathrm{trk}}\ge 50$. Such a structure is not predicted by the Monte-Carlo simulation. The harmonic anisotropy coefficients $v_n$, which result from the Fourier expansion of the two-particle correlation functions, were also measured for the first time in $e^{+}{e}^{-}$ data, and compared to PYTHIA6 predictions and to the results obtained in proton-proton collisions. The results presented in the Letter provide novel experimental constraints on the formation of collective phenomena in point-like $e^{+}{e}^{-}$ collisions.

   ↳ hep-exnucl-exPLB(2024)·47 citations
7. 07*

   Sympathetic cooling of trapped Th3+ alpha-recoil ions for laser spectroscopy

   G. Zitzer🇩🇪 · J. Tiedau🇩🇪 · M. V. Okhapkin🇩🇪 · K. Zhang🇩🇪 · C. Mokry🇩🇪 · J. Runke🇩🇪 · Ch. E. Düllmann🇩🇪 · E. Peik🇩🇪

   Sympathetic cooling of Th${}^{3+}$ ions is demonstrated in an experiment where ${}^{229}$Th and ${}^{230}$Th are extracted from uranium recoil ion sources and are confined in a linear Paul trap together with laser-cooled ${}^{88}$Sr${}^{+}$ ions. Because of their similar charge-to-mass ratios the ions are closely coupled and arrange themselves in two-species Coulomb crystals, containing up to a few tens of Th${}^{3+}$ ions. To show the suitability of the sympathetically cooled Th${}^{3+}$ ions for high-resolution laser spectroscopy, the absolute frequencies and isotope shifts of 5F${}_{5/2}$\,$\to$\,6D${}_{5/2}$ and 5F${}_{7/2}$\,$\to$\,6D${}_{5/2}$ transitions of ${}^{230}$Th${}^{3+}$ have been measured. The system is developed for hyperfine spectroscopy of electronic transitions of nuclear ground and isomeric states in ${}^{229}$Th${}^{3+}$.

   ↳ physics.atom-phnucl-exPRA(2024)·7 citations
8. 08*

   Evolution and fluctuations of chiral chemical potential in heavy ion collisions

   Vladimir Kovalenko🇷🇺

   The possible appearance of the effects of local parity breaking in the QCD medium formed in heavy ion collisions due to violation of chiral symmetry can be quantified by corresponding chiral chemical potential ${\mu }_5$. The experimental observables sensitive to the effects of local parity violation in strong interaction include search for polarisation splitting of the ${\rho }_0$ and ${\omega }_0$ mesons via angular dependence of spectral functions in their decay to leptons. In this paper we study the space-time evolution and fluctuations of ${\mu }_5$ using relativistic hydrodynamics and estimate their effect on the light vector meson polarization splitting in Pb-Pb collisions at LHC energy.

   ↳ hep-phnucl-exIJMPE(2024)·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.