Tue·Jun 4, 2024Tuesday·June 4, 2024

1. 01*

   A saga on the $\gamma$-decay branching ratio of the Hoyle state

   W. Paulsen🇳🇴 · K. C. W. Li🇿🇦 · S. Siem🇳🇴 · V. W. Ingeberg🇳🇴 · A. C. Larsen🇳🇴 · T. K. Eriksen🇳🇴 · H. C. Berg🇺🇸 · F. L. B. Garrote🇳🇴 · D. Gjestvang · A. Görgen🇳🇴 · M. Markova🇳🇴 · V. Modamio🇳🇴 and 3 other authors

   The radiative branching ratio of the Hoyle state is crucial to estimate the triple-$\alpha$ reaction rate in stellar environments at medium temperatures of $T=0.1$ to 2 GK. Knowledge of the $\gamma$-decay channel is critical as this is the dominant radiative decay channel for the Hoyle state. A recent study by Kibédi et al. [Phys. Rev. Lett. 125, 182701 (2020)] has challenged our understanding of this astrophysically significant branching ratio and its constraints. The main purpose was to perform a new measurement of the $\gamma$-decay branching ratio of the Hoyle state to deduce the radiative branching ratio of the Hoyle state, an additional objective was to independently verify aspects of the measurement conducted by Kibédi et al. For the primary experiment of this work the Hoyle state was populated by the ${}^{12}\text{C}(p,p^{\prime })$ reaction at 10.8 MeV at the Oslo Cyclotron Laboratory. The $\gamma$-decay branching ratio was deduced through triple-coincidence events between a proton populating the Hoyle state and the subsequent $\gamma$-ray cascade. An independent analysis of the 2014 data published by Kibédi et al. has been carried out. From the main experiment of this work, a $\gamma$-decay branching ratio of the Hoyle state was determined as ${\Gamma }_{\gamma }^{7.65}/{\Gamma }^{7.65}=4.0(3)\times 10^{-4}$, yielding a radiative branching ratio of ${\Gamma }_{\text{rad}}/\Gamma =4.1(4)\times 10^{-4}$. The reanalysis of the 2014 experiment in this work yielded ${\Gamma }_{\gamma }^{7.65}/{\Gamma }^{7.65}=4.5(6)\times 10^{-4}$, with a radiative branching ratio of ${\Gamma }_{\text{rad}}/\Gamma =4.6(6)\times 10^{-4}$. The measurements of the radiative branching ratio of the Hoyle state in this work is in excellent agreement with several recent studies, as well as the previously adopted ENSDF average of ${\Gamma }_{\text{rad}}/\Gamma =4.16(11)\times 10^{-4}$.

   nucl-exPRC(2025)·4 citations
2. 02*

   $K^{+}\Lambda (1520)$ photoproduction at forward angles near threshold with the BGOOD experiment

   E.O. Rosanowski🇩🇪 · T.C. Jude🇩🇪 · S. Alef🇩🇪 · A.J. Clara Figueiredo🇩🇪 · D.D Burdeinyi🇺🇦 · P.L. Cole🇺🇸 · R. Di Salvo🇮🇹 · D. Elsner🇩🇪 · A. Fantini🇮🇹 · O. Freyermuth🇩🇪 · F. Frommberger🇩🇪 · V.B Ganenko🇺🇦 and 13 other authors

   The differential cross section for $\gamma p\to K^{+}\Lambda (1520)$ was measured from threshold to a centre-of-mass energy of 2090\,MeV at forward angles at the BGOOD experiment. The high statistical precision and resolution in centre-of-mass energy and angle allows a detailed characterisation of this low-momentum transfer kinematic region. The data agree with a previous LEPS measurement and support effective Lagrangian models that indicate that the contact term dominates the cross section near threshold.

   nucl-exEPJA(2025)·7 citations
3. 03*

   Low energy alpha-nucleus optical potential studied via (a,n) cross section measurements on Te isotopes

   Zs. Mátyus · Gy. Gyürky🇭🇺 · P. Mohr🇺🇸 · A. Angyal · Z. Halász🇭🇺 · G.G. Kiss🇭🇺 · Á Tóth · T. Szücs🇭🇺 · Zs. Fülöp

   In several processes of stellar nucleosynthesis, like the astrophysical gamma-process, nuclear reactions involving alpha particles play an important role. The description of these reactions necessitates the knowledge of the alpha-nucleus optical model potential (AOMP) which is highly ambiguous at low, astrophysical energies. This ambiguity introduces a substantial uncertainty in the stellar models for predicting elemental and isotopic abundances. The experimental study of the AOMP is thus necessary which can be implemented by measuring the cross section of alpha-induced nuclear reactions. At low energies, (a,n) reactions are suitable for such a purpose. Therefore, in the present work, the (a,n) cross sections of four Te isotopes have been measured, mostly for the first time, and compared with theoretical predictions. The (a,n) cross sections of 120,122,124,130Te have been measured in the energy range between about 10 and 17 MeV using the activation method. The detection of the gamma radiation following the decay of the radioactive reaction products were used to determine the cross sections. The measured cross sections are compared with statistical model calculations obtained from the widely used TALYS nuclear reaction simulation code. Predictions using various available AOMPs are investigated. It is found that the recently developed Atomki-V2 AOMP provides the best description for all studied reactions and this potential also reproduces well the total reaction cross sections from elastic scattering experiments, when they are available in literature. We recommend therefore to use the astrophysical reaction rates based on this potential for nucleosynthesis models of heavy elements.

   nucl-exastro-ph.SRnucl-thPRC(2024)·2 citations
4. 04*

   Parton distribution functions and fragmentation functions of spin-1 hadrons

   S. Kumano🇯🇵

   Structure functions of the spin-1 deuteron will be investigated experimentally from the late 2020's at various facilities such as Thomas Jefferson National Accelerator Facility, Fermi National Accelerator Laboratory, nuclotron-based ion collider facility, and electron-ion colliders. We expect that a new high-energy spin-physics field could be created by these projects. In this paper, the current theoretical status is explained for the structure functions of spin-1 hadrons, especially on parton distribution functions, transverse-momentum dependent parton distributions, and fragmentation functions. Related multiparton distribution functions are also shown.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJA(2024)·12 citations
5. 05*

   Development of large-volume ${}^{130}$TeO${}_2$ bolometers for the CROSS $2\beta$ decay search experiment

   F.T. Avignone III🇺🇸 · A.S. Barabash🇷🇺 · V. Berest🇫🇷 · L. Bergé🇫🇷 · J.M. Calvo-Mozota🇪🇸 · P. Carniti🇮🇹 · M. Chapellier🇫🇷 · I. Dafinei🇮🇹 · F.A. Danevich🇮🇹 · L. Dumoulin🇫🇷 · F. Ferella🇮🇹 · F. Ferri🇫🇷 and 27 other authors

   We report on the development of thermal detectors based on large-size tellurium dioxide crystals (45x45x45 mm), containing tellurium enriched in ${}^{130}$Te to about 91%, for the CROSS double-beta decay experiment. A powder used for the crystals growth was additionally purified by the directional solidification method, resulting in the reduction of the concentration of impurities by a factor 10, to a few ppm of the total concentration of residual elements (the main impurity is Fe). The purest part of the ingot (the first ~200 mm, about 80% of the total length of the cylindrical part of the ingot) was determined by scanning segregation profiles of impurities and used for the ${}^{130}$TeO${}_2$ powder production with no evidence of re-contamination. The crystal growth was verified with precursors produced from powder with natural Te isotopic composition, and two small-size (20x20x10 mm) samples were tested at a sea-level laboratory showing high bolometric and spectrometric performance together with acceptable ${}^{210}$Po content (below 10 mBq/kg). This growth method was then applied for the production of six large cubic ${}^{130}$TeO${}_2$ crystals and 4 of them were taken randomly to be characterized at the Canfranc underground laboratory, in the CROSS-dedicated low-background cryogenic facility. Two ${}^{130}$TeO${}_2$ samples were coated with a thin, $O$(100 nm), metal film in form of Al layer (on 4 sides) or AlPd grid (on a single side) to investigate the possibility to tag surface events by pulse-shape discrimination. Similarly to the small natural precursors, large-volume ${}^{130}$TeO${}_2$ bolometers show high performance and even better internal purity (${}^{210}$Po activity $\sim$ 1 mBq/kg, while activities of ${}^{228}$Th and ${}^{226}$Ra are below 0.01 mBq/kg), satisfying requirements for the CROSS and, potentially, next-generation experiments.

   ↳ physics.ins-detnucl-exJINST(2024)·5 citations
6. 06*

   Exploring doubly-heavy tetraquarks in constituent-quark-model based meson-meson coupled-channels approach

   P. G. Ortega🇪🇸 · D. R. Entem🇪🇸 · F. Fernandez🇪🇸 · J. Segovia🇪🇸

   The LHCb Collaboration announced in 2021 the discovery of a new tetraquark-like state, named $T_{cc}^{+}$, with minimum quark content $cc\bar{u}\bar{d}$, close to the $D^0{D}^{\ast +}$ threshold. This has motivated countless theoretical works trying to identify the dynamics which is responsible of the formation of such state; in particular, the one performed by us in Ref. \cite{Ortega:2022efc}, where a $D^0{D}^{\ast +}$ molecular candidate whose mass, width, scattering length and effective ranges are in reasonable agreement with experimental measurements. We explore herein the possibility of having $T_{cc}^{+}$ partners in all doubly-heavy tetraquark sectors, considering doubly represented light antiquarks $u$, $d$ or $s$, and taking into account all possible spin-parity quantum numbers. The computation is done using a constituent-quark-model based meson-meson coupled-channels framework which has been tested many times in the last fifteen years describing conventional heavy mesons and baryons, their coupling with hadron-hadron thresholds but also in exploring its application to compact multiquark structures. The advantage of using an approach with such a relatively large history is that it allows us to make predictions because all the parameters have already been constrained from our previous works. Then, from this perspective, we present a parameter-free model-dependent prediction of doubly-heavy tetraquarks that may be partners of the discovered $T_{cc}^{+}$ state.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2024)·5 citations
7. 07*

   neuSIM4: A comprehensive GEANT4 based neutron simulation code

   J. Park🇰🇷 · F. C. E. Teh🇺🇸 · M. B. Tsang🇺🇸 · K. W. Brown🇺🇸 · Z. Chajecki🇺🇸 · B. Hong🇰🇷 · T. Lokotko🇨🇳 · W. G. Lynch🇺🇸 · J. Wieske · K. Zhu🇺🇸

   A new neutron SIMulation program based on the versatile GEANT4 toolkit, neuSIM4, has been developed to describe interactions of neutrons in the NE213 liquid scintillator from 0.1 to 3000 MeV. neuSIM4 is designed to accommodate complicated modern detector geometry setups with multiple scintillator detectors, each of which can be outfitted with more than one photo-multiplier. To address a broad spectrum of neutron energies, two new neutron interaction physics models, KSCIN and NxQMD, have been implemented in GEANT4. For neutrons with energy below 110 MeV, we incorporate a total of eleven neutron induced reaction channels on hydrogen and carbon nuclei, including nine carbon inelastic reaction channels, into KSCIN. Beyond 110 MeV, we implement a neutron induced reaction model, NxQMD, in GEANT4. We use its results as reference to evaluate other neutron-interaction physics models in GEANT4. We find that results from an existing cascade physics model (INCL) in GEANT4 agree very well with the results from NxQMD, and results from both codes agree with new and existing light response data. To connect KSCIN to NxQMD or INCL, we introduce a transition region where the contribution of neuSIM4 linearly decreases with corresponding increased contributions from NxQMD or INCL. To demonstrate the application of the new code, we simulate the light response and performance of a 2 x 2 m2 neutron detector wall array consisting of 25 2m-long scintillation bars. We are able to compare the predicted light response functions to the shape of the experimental response functions and calculate the efficiency of the neutron detector array for neutron energies up to 200 MeV. These simulation results will be pivotal for understanding the performance of modern neutron arrays with intricate geometries, especially in the measurements of neutron energy spectra in heavy-ion reactions.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2024)·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.