Thu·Oct 7, 2021Thursday·October 7, 2021

1. 01*

   First beams at Neutrons For Science

   X. Ledoux🇫🇷 · J.C. Foy🇫🇷 · J.E. Ducret🇫🇷 · A.M. Frelin🇫🇷 · D. Ramos🇫🇷 · J. Mrazek🇨🇿 · E. Simeckova🇨🇿 · R. Behal🇨🇿 · L. Caceres🇫🇷 · V. Glagolev🇨🇿 · B. Jacquot🇫🇷 · A. Lemasson🇫🇷 and 4 other authors

   The neutrons for science facility (NFS), the first operational experimental area of the new GANIL/SPIRAL-2 facility, received its first beams in December 2019. Proton-induced reaction cross-sections as well as neutron beam characteristics were measured during the first commissioning phases. The first results, showing the features of the facility, are presented here and compared with previously published data. The physics cases and the first accepted experiments are presented as well.

   nucl-exphysics.ins-detEPJA(2021)·26 citations
2. 02*

   Properties of the fast fission and the coincident emissions of light charged particles in ${}^{40}$Ar + ${}^{197}$Au reactions at 30 MeV/u

   Xinyue Diao🇨🇳 · Yijie Wang🇨🇳 · Fenhai Guan🇨🇳 · Dawei Si · Qianghua Wu · Yan Huang🇨🇳 · Liming Lyu · Yuhao Qin🇨🇳 · Zhi Qin🇨🇳 · Dong Guo · Yaopeng Zhang🇺🇸 · Xuan Zhao🇺🇸 and 27 other authors

   The experiment of Ar+Au reactions at 30 MeV/u have been performed using the Compact Spectrometer for Heavy IoN Experiments (CSHINE) in phase I. The light-charged particles are measured by the silicon stripe telescopes in coincidence with the fission fragments recorded by the parallel plate avalanche counters. The distribution properties of the azimuth difference $\Delta \varphi$ and the time-of-flight difference $\Delta TOF$ of the fission fragments are presented varying the folding angles which represents the linear momentum transfer from the projectile to the reaction system. The relative abundance of the light charged particles in the fission events to the inclusive events is compared as a function of the laboratory angle ${\theta }_{\mathrm{lab}}$ ranging from $18^{\circ }$ to $60^{\circ }$ in various folding angle windows. The angular evolution of the yield ratios of p/d and t/d in coincidence with fission fragments is investigated. In a relative comparison, tritons are more abundantly emitted at small angles, while protons are more abundant at large angles. The angular evolution of the neutron richness of the light-charged particles is consistent with the results obtained in previous inclusive experiments.

   nucl-ex0 citations
3. 03*

   Performance of BeBe, a proposed dedicated beam-beam monitoring detector for the MPD-NICA experiment at JINR

   Marco Alberto Ayala Torres🇲🇽 · Lucina Gabriela Espinoza Beltrán🇲🇽 · Marcos Aurelio Fontaine Sánchez🇲🇽 · Luis A. Hernández-Cruz🇲🇽 · Luis Manuel Montaño🇲🇽 · Braian Adair Maldonado Luna🇲🇽 · Eduardo Moreno-Barbosa🇲🇽 · Lucio Fidel Rebolledo Herrera🇲🇽 · Mario Rodríguez-Cahuantzi🇲🇽 · Valeria Z. Reyna-Ortiz🇵🇱 · Guillermo Tejeda-Muñoz🇲🇽 · C.H. Zepeda Fernández🇲🇽

   The Multipurpose Detector (MPD) is an experimental array, currently under construction, designed to study the nuclear matter created during the collisions that will be provided by the Nuclotron-based Ion Collider fAcility (NICA) at JINR. The MPD-NICA experiment consists of a typical array of particle detectors as those used to study heavy-ion collisions at LHC and RHIC. To increase the trigger capabilities of MPD for stage 2 of NICA operation, a detector conformed by two arrays of 80 plastic scintillator cells each located symmetrically at opposite sides of the interaction point of MPD is proposed (BeBe). Based on Monte Carlo simulations, a discussion of the potential physics performance of BeBe detector is given for triggering tasks and for the resolution in the determination of the event plane reaction and the centrality of the collisions at NICA. Also, laboratory measurements to estimate the time resolution of individual BeBe cells prototypes are presented. It is shown that a time resolution between 0.65 and 1.48 ns can be reached depending on the number of photosensors employed to collect the scintillation photons. The BeBe detector will be complementary to FFD and FHCAL forward detectors.

   ↳ physics.ins-dethep-exnucl-exJINST(2022)·2 citations
4. 04*

   Understanding the systematic differences in extractions of the proton electric form factors at low-$Q^2$

   Jingyi Zhou🇺🇸 · Vladimir Khachatryan🇺🇸 · Haiyan Gao🇺🇸 · Simon Gorbaty🇺🇸 · Douglas W. Higinbotham🇺🇸

   Systematic differences exist between values of the proton's electric form factors in the low-$Q^2$ region extracted by different experimental and theoretical groups, though they are all making use of basically the same electron-proton scattering data. To try understand the source of these differences, we make use of the analytically well-behaved rational (N=1, M=1) function, a predictive function that can be reasonably used for extrapolations at $Q^2\to 0$. First, we test how well this deceptively simple two-parameter function describes the extremely complex and state-of-the-art dispersively improved chiral effective field theory calculations. Second, we carry out a complete re-analysis of the 34 sets of eletron-proton elastic scattering cross-section data of the Mainz A1 Collaboration with its unconstrained 31 normalization parameters up to $Q^2=0.5(GeV/c{)}^2$. We find that subtle shifts in the normalization parameters can result in relatively large changes in the extracted physical qualities. In conclusion, we show that by simply using a well-behaved analytic function, the apparent discrepancy between recent form-factor extractions can be resolved.

   ↳ hep-phnucl-exnucl-thPRC(2022)·10 citations
5. 05*

   Moat Regimes in QCD and their Signatures in Heavy-Ion Collisions

   Fabian Rennecke🇩🇪 · Robert D. Pisarski🇺🇸

   Dense QCD matter can exhibit spatially modulated regimes. They can be characterized by particles with a moat spectrum, where the minimum of the energy is over a sphere at nonzero momentum. Such a moat regime can either be a precursor for the formation inhomogeneous condensates, or signal a quantum pion liquid. We introduce the quantum pion liquid and discuss the underlying physics of the moat regime based on studies in low-energy models and preliminary results in QCD. Heavy-ion collisions at small beam energies have the potential to reveal the rich phase structure of QCD at low temperature and nonzero density. We show how moat regimes can be discovered through such collisions. Particle production is enhanced at the bottom of the moat, resulting in a peak at nonzero momentum, instead of zero, in the particle spectrum. Particle number correlations can even increase by several orders of magnitude at nonzero momentum in the moat regime.

   ↳ hep-phnucl-exnucl-thPoS(2022)·22 citations
6. 06*

   Recent advancements of the experiment to search for $2K$-capture in ${}^{124}$Xe using a Large Low-background Proportional Counter

   O. D. Petrenko · I. D. Fedorets · A. M. Gangapshev🇷🇺 · Yu. M. Garilyuk · V. V. Kazalov🇷🇺 · V. V. Kuzminov🇷🇺 · S. I. Panasenko🇺🇦 · S. S. Ratkevich🇺🇦

   A new method for correcting the charge signal from the large proportional counter is proposed. The correction method makes it possible to take into account the loss of primary ionization electrons in the presence of weakly increasing micro impurities of electronegative gases during long-term measurements. It allows increasing the efficiency of the selection of useful events and thereby increasing the sensitivity to $2\nu 2K$-decay in ${}^{124}$Xe at the level of $2\times 10^{22}$ from over six years of measurements using a large proportional counter. Analysis of the calibration data, taking into account the new method for correcting the energy release in the detector, made it possible to register events from double $K$ photoionization by a single photon.

   ↳ physics.ins-detnucl-exJ.Phys.Conf.Ser.(2021)·0 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.