Tue·May 11, 2021Tuesday·May 11, 2021

1. 01*

   The ${}^6$H states studied in the ${}^2\text{He}{(}^8\text{He}{,}^4\text{He})$ reaction and evidence of extremely correlated character of the ${}^5$H ground state

   E.Yu. Nikolskii🇷🇺 · I.A. Muzalevskii🇷🇺 · A.A. Bezbakh🇷🇺 · V. Chudoba🇷🇺 · S.A. Krupko🇷🇺 · S.G. Belogurov🇷🇺 · D. Biare🇷🇺 · A.S. Fomichev🇷🇺 · E.M. Gazeeva🇷🇺 · A.V. Gorshkov🇺🇸 · L.V. Grigorenko🇷🇺 · G. Kaminski🇷🇺 and 22 other authors

   The extremely neutron-rich system ${}^6$H was studied in the direct ${}^2\text{H}{(}^8\text{He},{}^4\text{He}{)}^6$H transfer reaction with a $26A$ MeV secondary ${}^8$He beam. The measured missing mass spectrum shows a broad bump at $\sim 4-8$ MeV above the ${}^3$H+$3n$ decay threshold. This bump can be interpreted as a broad resonant state in ${}^6$H at $6.8(5)$ MeV. The population cross section of such a presumably $p$-wave state (or may be few overlapping states) in the energy range from 4 to 8 MeV is $d\sigma /d{\Omega }_{\text{c.m.}}\simeq 190_{-80}^{+40}$ $\mu$b/sr in the angular range $5^{\circ }<{\theta }_{\text{c.m.}}<16^{\circ }$. The obtained missing mass spectrum is practically free of the ${}^6$H events below 3.5 MeV ($d\sigma /d{\Omega }_{\text{c.m.}}\lesssim 5$ $\mu$b/sr in the same angular range). The steep rise of the ${}^6$H missing mass spectrum at $\sim 3$ MeV allows to derive the lower limit for the possible resonant-state energy in ${}^6$H to be $4.5(3)$ MeV. According to the paring energy estimates, such a $4.5(3)$ MeV resonance is a realistic candidate for the ${}^6$H ground state (g.s.). The obtained results confirm that the decay mechanism of the ${}^7$H g.s.\ (located at 2.2 MeV above the ${}^3$H+$4n$ threshold) is the "true" (or simultaneous) $4n$ emission. The resonance energy profiles and the momentum distributions of fragments of the sequential ${}^6$H$\to {}^5$H(g.s.)+$n\to {}^3$H+$3n$ decay were analyzed by the theoretically-updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the ${}^3$H fragments in the ${}^6$H rest frame indicate very strong "dineutron-type" correlations in the ${}^5$H ground state decay.

   nucl-exnucl-thPRC(2022)·9 citations
2. 02*

   Practical tests of neutron transmission imaging with a superconducting kinetic-inductance sensor

   The Dang Vu🇯🇵 · Hiroaki Shishido🇯🇵 · Kazuya Aizawa🇯🇵 · Kenji M. Kojima🇨🇦 · Tomio Koyama🇯🇵 · Kenichi Oikawa🇯🇵 · Masahide Harada🇯🇵 · Takayuki Oku🇯🇵 · Kazuhiko Soyama🇯🇵 · Shigeyuki Miyajima🇯🇵 · Mutsuo Hidaka🇯🇵 · Soh Y. Suzuki🇯🇵 and 5 other authors

   Samples were examined using a superconducting (Nb) neutron imaging system employing a delay-line technique which in previous studies was shown to have high spatial resolution. We found excellent correspondence between neutron transmission and scanning electron microscope (SEM) images of Gd islands with sizes between 15 and 130 micrometer which were thermally-sprayed onto a Si substrate. Neutron transmission images could be used to identify tiny voids in a thermally-sprayed continuous Gd2O3 film on a Si substrate which could not be seen in SEM images. We also found that neutron transmission images revealed pattern formations, mosaic features and co-existing dendritic phases in Wood's metal samples with constituent elements Bi, Pb, Sn and Cd. These results demonstrate the merits of the current-biased kinetic inductance detector (CB-KID) system for practical studies in materials science. Moreover, we found that operating the detector at a more optimal temperature (7.9 K) appreciably improved the effective detection efficiency when compared to previous studies conducted at 4 K. This is because the effective size of hot-spots in the superconducting meanderline planes increases with temperature, which makes particle detections more likely.

   ↳ cond-mat.supr-connucl-exNucl.Instrum.Meth.A(2021)·0 citations
3. 03*

   Scale symmetry breaking, quantum anomalous energy and proton mass decomposition

   Xiangdong Ji🇺🇸 · Yizhuang Liu🇵🇱 · Andreas Schäfer🇩🇪

   We study the anomalous scale symmetry breaking effects on the proton mass in QCD due to quantum fluctuations at ultraviolet scales. We confirm that a novel contribution naturally arises as a part of the proton mass, which we call the quantum anomalous energy (QAE). We discuss the QAE origins in both lattice and dimensional regularizations and demonstrate its role as a scheme-and-scale independent component in the mass decomposition. We further argue that QAE role in the proton mass resembles a dynamical Higgs mechanism, in which the anomalous scale symmetry breaking field generates mass scales through its vacuum condensate, as well as its static and dynamical responses to the valence quarks. We demonstrate some of our points in two simpler but closely related quantum field theories, namely the 1+1 dimensional non-linear sigma model in which QAE is non-perturbative and scheme-independent, and QED where the anomalous energy effect is perturbative calculable.

   ↳ hep-phhep-latnucl-exnucl-thNPB(2021)·29 citations
4. 04*

   Measuring neutron skin by grazing isobaric collisions

   Hao-jie Xu🇨🇳 · Hanlin Li🇨🇳 · Ying Zhou🇨🇳 · Xiaobao Wang🇨🇳 · Jie Zhao🇺🇸 · Lie-Wen Chen🇨🇳 · Fuqiang Wang🇺🇸

   Neutron skin thickness ($\Delta r_{\mathrm{np}}$) of nuclei and the inferred nuclear symmetry energy are of critical importance to nuclear physics and astrophysics. It is traditionally measured by nuclear processes with significant theoretical uncertainties. We recently proposed an indirect measurement of the $\Delta r_{\mathrm{np}}$ by charged hadron multiplicities in central isobaric collisions at relativistic energies, which are sensitive to nuclear densities. In this Letter, we propose a direct measurement of the $\Delta r_{\mathrm{np}}$ by using net-charge multiplicities in ultra-peripheral (grazing) collisions of those isobars, under the assumption that they are simple superimposition of nucleon-nucleon interactions. We illustrate this novel approach by the TRENTO and URQMD models.

   ↳ nucl-thnucl-exPRC(2022)·27 citations
5. 05*

   Prospects for diffractive dijet photoproduction at the EIC

   V. Guzey🇷🇺 · M. Klasen🇩🇪

   We discuss the prospects of diffractive dijet photoproduction at the EIC to distinguish different fits of diffractive proton PDFs, different schemes of factorization breaking, to determine diffractive nuclear PDFs and pion PDFs from leading neutron production.

   ↳ hep-phhep-exnucl-exSciPost Phys.Proc.(2022)·0 citations
6. 06*

   Halo effective field theory analysis of one-neutron knockout reactions of ${}^{11}\mathrm{Be}$ and ${}^{15}\mathrm{C}$

   Chloë Hebborn🇺🇸 · Pierre Capel🇧🇪

   Background: One-nucleon knockout reactions provide insightful information on the single-particle structure of nuclei. When applied to one-neutron halo nuclei, they are purely peripheral, suggesting that they could be properly modeled by describing the projectile within a Halo Effective Field Theory (Halo-EFT). Purpose: We reanalyze the one-neutron knockout measurements of ${}^{11}$Be and ${}^{15}$C-both one-neutron halo nuclei-on beryllium at about 60MeV/nucleon. We consider Halo-EFT descriptions of these nuclei which already provide excellent agreement with breakup and transfer data. Method: We include a Halo-EFT description of the projectile within an eikonal-based model of the reaction and compare its outcome to existing data. Results: Excellent agreement with experiment is found for both nuclei. The asymptotic normalization coefficients inferred from this comparison confirm predictions from \emph{ab initio} nuclear-structure calculations and values deduced from transfer data. Conclusions: Halo-EFT can be reliably used to analyze one-neutron knockout reactions measured for halo nuclei and test predictions from state-of-the-art nuclear structure models on these experimental data.

   ↳ nucl-thnucl-exPRC(2021)·21 citations
7. 07*

   Emergence of rotational modes in nuclear fission

   Bency John🇮🇳

   Dinuclear systems that occur in the post-saddle to scission stage in nuclear fission process are special transient formations. The diabatic evolution at this stage is studied using the methods of non-equilibrium thermodynamics. A novel explanation for the emergence of intrinsic rotational modes that occur in such a dinucleus is developed by identifying these modes together as an open subsystem that exchanges matter and energy with its environment. The environment consists of all remaining degrees of freedom of the dinucleus, and a weak coupling of the subsystem to this environment facilitates a diabatic energy exchange. Under appropriate non-equilibrium conditions, the available energy is coupled to the work needed for the emergence of self organizing rotational modes. This comes at the expense of increasing microscopic disorder in the form of intrinsic excitations in the prefragments. A simple formalism is presented such that the magnitudes of relevant energy flow through the subsystem are obtained in terms of entropy production rate, entropy expulsion rate and net rate of change of entropy in sub-units of $MeVz{s}^{-1}{K}^{-1}$.

   ↳ nucl-thnlin.AOnucl-ex0 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.