Tue·Jul 30, 2024Tuesday·July 30, 2024

1. 01*

   Magicity versus superfluidity around ${}^{28}$O viewed from the study of ${}^{30}$F

   J. Kahlbow🇩🇪 · T. Aumann🇩🇪 · O. Sorlin🇫🇷 · Y. Kondo🇯🇵 · T. Nakamura🇯🇵 · F. Nowacki🇫🇷 · A. Revel🇫🇷 · N. L. Achouri🇫🇷 · H. Al Falou🇱🇧 · L. Atar🇰🇷 · H. Baba🇯🇵 · K. Boretzky🇩🇪 and 75 other authors

   The neutron-rich unbound fluorine isotope ${}^{30}$F${}_{21}$ has been observed for the first time by measuring its neutron decay at the SAMURAI spectrometer (RIBF, RIKEN) in the quasi-free proton knockout reaction of ${}^{31}$Ne nuclei at 235 MeV/nucleon. The mass and thus one-neutron-separation energy of ${}^{30}$F has been determined to be $S_n=-472\pm 58(stat.)\pm 33(sys.)$ keV from the measurement of its invariant-mass spectrum. The absence of a sharp drop in $S_n$(${}^{30}$F) shows that the ``magic'' $N=20$ shell gap is not restored close to ${}^{28}$O, which is in agreement with our shell-model calculations that predict a near degeneracy between the neutron $d$ and $fp$ orbitals, with the $1p_{3/2}$ and $1p_{1/2}$ orbitals becoming more bound than the $0f_{7/2}$ one. This degeneracy and reordering of orbitals has two potential consequences: ${}^{28}$O behaves like a strongly superfluid nucleus with neutron pairs scattering across shells, and both ${}^{29,31}$F appear to be good two-neutron halo-nucleus candidates.

   nucl-exnucl-thPRL(2024)·11 citations
2. 02*

   Measurement of the Sequential $3\alpha$ Process in the Photodissociation of ${}^{12}\mathrm{C}$

   Resmi K.Bharathan · Midhun C.V · M.M Musthafa · Sreena M🇮🇳 · Silpa Ajaykumar · Farhana Thesni M.P · Swapna B · Vafiya Thaslim T.T · Shaima A🇯🇵 · Nived K · Akhil R · Anagha P.K and 5 other authors

   The cross sections for the ${}^{12}\mathrm{C}(\gamma ,\alpha {)}^8\mathrm{Be}\to 3\alpha$ reaction have been successfully measured using exclusive coincidence between three $\alpha$ particles, minimizing Compton background. Sequential breakup kinematics are evident, and the cross sections are presented as locally averaged histogram values. Theoretical \textsc{Fresco} CDCC-CRC calculations reproduce the experimental data, showing that the process involves electromagnetic coupling to both ${}^8{\mathrm{Be}}^{0^{+}}$ and ${}^8{\mathrm{Be}}^{2^{+}}$ states. This study confirms that the ${}^{12}\mathrm{C}(\gamma ,\alpha {)}^8\mathrm{Be}\to 3\alpha$ reaction proceeds via a sequential mechanism, crucial for understanding its significance in radiotherapy dosimetry.

   nucl-exPRC(2025)·0 citations
3. 03*

   Study of one-step and two-step neutron transfer in the reaction ${}^6$Li + ${}^9$Be

   Azhibekov Aidos · Lukyanov Sergey · Penionzhkevich Yuri · Urazbekov Bakytzhan · Naumenko Mikhail · Samarin Vyacheslav · Issatayev Talgat · Maslov Vladimir · Mendibayev Kayrat · Aznabayev Dauren · Temirzhanov Alisher

   The paper presents the results of experiments on measuring the cross sections for elastic scattering and nucleon transfer channels in the ${}^6$Li + ${}^9$Be reaction at an incident energy of 68 MeV: ${}^9$Be(${}^6$Li,${}^6$Li)${}^9$Be, ${}^9$Be(${}^6$Li,${}^7$Li)${}^8$Be, ${}^9$Be(${}^6$Li,${}^7$Li)${}^8$Be${}_{2+}$, ${}^9$Be(${}^6$Li,${}^8$Li)${}^7$Be, ${}^9$Be(${}^6$Li,${}^7$Be)${}^8$Li. The aim is to reveal the manifestation of the cluster structure of ${}^9$Be. Theoretical analysis of the contributions of one-step and two-step neutron transfer mechanisms is performed using the distorted wave Born approximation method with the Fresco code. Good agreement between the calculations and the experimental data was obtained for the channels of elastic scattering ${}^9$Be(${}^6$Li,${}^6$Li)${}^9$Be, neutron ${}^9$Be(${}^6$Li,${}^7$Li)${}^8$Be and proton transfer ${}^9$Be(${}^6$Li,${}^7$Be)${}^8$Li, as well as the transfer of two neutrons ${}^9$Be(${}^6$Li,${}^8$Li)${}^7$Be. It is shown that the dineutron cluster transfer mechanism makes a dominant contribution to the ${}^9$Be(${}^6$Li,${}^8$Li)${}^7$Be reaction channel at forward angles.

   nucl-exnucl-thCPC(2024)·3 citations
4. 04*

   Comparative studies of plastic scintillator strips with high technical attenuation length for the total-body J-PET scanner

   L. Kaplon🇵🇱 · J. Baran · N. Chug🇵🇱 · A. Coussat🇵🇱 · C. Curceanu🇮🇹 · E. Czerwinski🇵🇱 · M. Dadgar🇵🇱 · K. Dulski🇮🇹 · J. Gajewski · A. Gajos🇵🇱 · B. Hiesmayr🇦🇹 · E. Kavya Valsan and 22 other authors

   Plastic scintillator strips are considered as one of the promising solutions for the cost-effective construction of total-body positron emission tomography, (PET) system. The purpose of the performed measurements is to compare the transparency of long plastic scintillators with dimensions 6 mm x 24 mm x 1000 mm and with all surfaces polished. Six different types of commercial, general purpose, blue-emitting plastic scintillators with low attenuation of visible light were tested, namely: polyvinyl toluene-based BC-408, EJ-200, RP-408, and polystyrene-based Epic, SP32 and UPS-923A. For determination of the best type of plastic scintillator for totalbody Jagiellonian positron emission tomograph (TB-J-PET) construction, emission and transmission spectra, and technical attenuation length (TAL) of blue light-emitting by the scintillators were measured and compared. The TAL values were determined with the use of UV lamp as excitation source, and photodiode as light detector. Emission spectra of investigated scintillators have maxima in the range from 420 nm to 429 nm. The BC-408 and EJ-200 have the highest transmittance values of about 90% at the maximum emission wavelength measured through a 6 mm thick scintillator strip and the highest technical attenuation length reaching about 2000 mm, allowing assembly of long detection modules for time-of-flight (TOF) J-PET scanners. Influence of the 6 mm x 6 mm, 12 mm x 6 mm, 24 mm x 6 mm cross-sections of the 1000 mm long EJ-200 plastic scintillator on the TAL and signal intensity was measured. The highest TAL value was determined for samples with 24 mm x 6 mm cross-section.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·11 citations
5. 05*

   Investigation of kaonic atom optical potential by the high precision data of kaonic ${}^3$He and ${}^4$He atoms

   J. Yamagata-Sekihara (Kyoto Sangyo U.)🇯🇵 · Y. Iizawa (Tokyo Inst. Tech.)🇯🇵 · D. Jido (Tokyo Inst. Tech.)🇯🇵 · N. Ikeno (Tottori U.)🇯🇵 · T. Hashimoto (Nishina Car., RIKEN and RIKEN)🇯🇵 · S. Okada (Chubu U. and RIKEN)🇯🇵 · S. Hirenzaki (Nara Women's U.)🇯🇵

   We theoretically investigate kaonic atom states based on the latest high precision data of the $2p$ states of the kaonic atoms in ${}^3$He and ${}^4$He (J-PARC E62). We consider the phenomenological form for the optical potential proportional to the nuclear density distributions and determine the potential parameters by the latest data. We find two sets of potential parameters for each of $K^{-}{-}^3$He and $K^{-}{-}^4$He that reproduce the data. We then extract the potential parameters consistent with the data of ${}^3$He and ${}^4$He atoms simultaneously. Using the potential, we investigate the structure of the kaonic atoms and kaonic nuclei for various nuclei up to Sn. We also report the optical potential parameters suited for the global description of the atomic data, the possible strong isospin dependence of the potential, and the different strength of the data of $K^{-}{-}^3$He and $K^{-}{-}^4$He in the restrictions on the potential parameters. In addition, we find that the study of the $1s$ states of the kaonic helium atom is very interesting as a next step, and the determination of the orbital angular momenta of the kaonic nuclear states is helpful for the unified understandings of the atomic and nuclear bound states of kaon because of the mutual influence between the atomic and the nuclear states of kaon with the same orbital angular momentum.

   ↳ nucl-thhep-exhep-phnucl-exPTEP(2025)·5 citations
6. 06*

   Likely existence of bound states and the Efimov effect in the triple-$J/\psi$ system

   Ya-Wen Pan🇨🇳 · Zhi-Wei Liu🇨🇳 · Li-Sheng Geng🇨🇳 · Atsushi Hosaka🇯🇵 · Xiang Liu🇨🇳

   The ground-breaking discovery of the first fully charmed tetraquark state $X(6900)$ in the $J/\psi J/\psi$ invariant mass distribution by the LHCb collaboration has inspired intensive theoretical studies. Various interpretations, such as molecular states, compact tetraquark states, and coupled-channel effects, have been proposed for these states. Of particular interest is the ongoing search for the triple-$J/\psi$ state--a fully-charmed hexaquark state. To deepen our understanding of the triple-$J/\psi$ state and to guide future experimental searches, we study the triple-$J/\psi$ system in this work employing the Gaussian expansion method and the $J/\psi J/\psi$ potential parameterized to yield a shallow bound state, as suggested in several theoretical works. Our results support a triple-$J/\psi$ bound state, even in cases where the attractive interaction between the two $J/\psi$ mesons is very weak. Moreover, our analysis implies the Efimov effect in the triple-$J/\psi$ system. In addition, we extend our investigation to the triple-${\rm Y}(1S)$ system and obtain results similar to those for the triple-$J/\psi$ system.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2024)·3 citations
7. 07*

   Particle production as a function of charged-particle flattenicity in pp collisions at $\sqrt{s}$ = 13 TeV

   ALICE Collaboration

   This paper reports the first measurement of the transverse momentum ($p_{\mathrm{T}}$) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at $\sqrt{s}=13$ TeV. Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by the V0 detector, $2.8<\eta <5.1$ and $-3.7<\eta <-1.7$. According to QCD-inspired phenomenological models, it shows sensitivity to multiparton interactions and is less affected by biases toward larger $p_{\mathrm{T}}$ due to local multiplicity fluctuations in the V0 acceptance than multiplicity. The analysis is performed in minimum-bias (MB) as well as in high-multiplicity events up to $p_{\mathrm{T}}=20$ GeV/$c$. The event selection requires at least one charged particle produced in the pseudorapidity interval $|\eta |<1$. The measured $p_{\mathrm{T}}$ distributions, average $p_{\mathrm{T}}$, kaon-to-pion and proton-to-pion particle ratios, presented in this paper, are compared to model calculations using PYTHIA 8 based on color strings and EPOS LHC. The modification of the $p_{\mathrm{T}}$-spectral shapes in low-flattenicity events that have large event activity with respect to those measured in MB events develops a pronounced peak at intermediate $p_{\mathrm{T}}$ ($2<p_{\mathrm{T}}<8$ GeV/$c$), and approaches the vicinity of unity at higher $p_{\mathrm{T}}$. The results are qualitatively described by PYTHIA, and they show different behavior than those measured as a function of charged-particle multiplicity based on the V0M estimator.

   ↳ hep-exnucl-exPRD(2025)·14 citations
8. 08*

   Comment on "Final CONUS results on coherent elastic neutrino nucleus scattering at the Brokdorf reactor"

   J.I. Collar🇺🇸 · C.M. Lewis🇺🇸

   We describe several omissions and deficiencies in the arguments presented by Ackermann et al. (arXiv:2401.07684), pointing at missing information necessary to back up its conclusions.

   ↳ hep-exhep-phnucl-exphysics.ins-det1 citation

* 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.