Tue·Jan 30, 2024Tuesday·January 30, 2024

1. 01*

   Direct high-precision measurement of the mass difference of ${}^{77}$As-${}^{77}$Se related to neutrino mass determination

   Z. Ge🇫🇮 · T. Eronen🇫🇮 · M. Ramalho🇫🇮 · A. de Roubin🇫🇷 · D. A. Nesterenko🇫🇮 · A. Kankainen🇫🇮 · O. Beliuskina🇫🇮 · R. de Groote🇫🇮 · S. Geldhof🇫🇮 · W. Gins🇫🇮 · M. Hukkanen🇫🇮 · A. Jokinen🇫🇮 and 11 other authors

   The first direct determination of the ground-state-to-ground-state ${\beta }^{-}$-decay $Q$-value of ${}^{77}$As to ${}^{77}$Se was performed by measuring their atomic mass difference utilizing the double Penning trap mass spectrometer, JYFLTRAP. The resulting $Q$-value is 684.463(70) keV, representing a remarkable 24-fold improvement in precision compared to the value reported in the most recent Atomic Mass Evaluation (AME2020). With the significant reduction of the uncertainty of the ground-state-to-ground-state $Q$-value and knowledge of the excitation energies in ${}^{77}$Se from $\gamma$-ray spectroscopy, the ground-state-to-excited-state $Q$-value of the transition ${}^{77}$As (3/2${}^{-}$, ground state) $\to$ ${}^{77}$Se${}^{\ast }$ (5/2${}^{+}$, 680.1035(17) keV) was refined to be 4.360(70) keV. We confirm that this potential low $Q$-value ${\beta }^{-}$-decay transition for neutrino mass determination is energetically allowed at a confidence level of about 60$\sigma$. Nuclear shell-model calculations with two well-established effective Hamiltonians were used to estimate the partial half-life for the low $Q$-value transition. The half-life was found to be of the order of 10${}^9$ years for this first-forbidden non-unique transition, which rules out this candidate a potential source for rare-event experiments searching for the electron antineutrino mass.

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

   On the half life of ${}^{71}$Ge and the Gallium Anomaly

   E. B. Norman🇺🇸 · A. Drobizhev🇺🇸 · N. Gharibyan🇺🇸 · K. E. Gregorich🇺🇸 · Yu. G. Kolomensky🇺🇸 · B. N. Sammis🇺🇸 · N. D. Scielzo🇺🇸 · J. A. Shusterman🇺🇸 · K. J. Thomas🇺🇸

   Recent discussions about the origin of the Gallium Anomaly have motivated a remeasurement of the half life of ${}^{71}$Ge. We have conducted three separate measurements using dedicated planar Ge detectors: one with ${}^{55}$Fe as a standard, one with ${}^{57}$Co as a standard, and one stand alone 71Ge measurement. Our results yield a half life of 11.468 +- 0.008 days, which is consistent with but significantly more precise than the currently accepted value. With this experiment, the potential explanation of the Gallium Anomaly being due to an unexpectedly long ${}^{71}$Ge half life has been ruled out, leaving the origin of the anomaly as an open question.

   nucl-exPRC(2024)·13 citations
3. 03*

   Simultaneous Measurement of Half-Life and Spectral Shape of ${}^{115}$In $\beta$-decay with an Indium Iodide Cryogenic Calorimeter

   L. Pagnanini🇮🇹 · G. Benato🇮🇹 · P. Carniti🇮🇹 · E. Celi🇮🇹 · D. Chiesa🇮🇹 · J. Corbett🇨🇦 · I. Dafinei🇮🇹 · S. Di Domizio🇮🇹 · P. Di Stefano🇨🇦 · S. Ghislandi🇮🇹 · C. Gotti🇮🇹 · D. L. Helis🇮🇹 and 12 other authors

   Current bounds on neutrino Majorana mass are affected by significant uncertainties in the nuclear calculations for neutrinoless double-beta decay. A key issue for a data-driven improvement of the nuclear theory is the actual value of the axial coupling constant $g_A$, which can be investigated through forbidden $\beta$-decays. We present the first measurement of 4${}^{th}$-forbidden $\beta$-decay of ${}^{115}$In with a cryogenic calorimeter based on Indium Iodide. Exploiting the enhanced spectral shape method for the first time to this isotope, our study accurately determines simultaneously spectral shape, $g_A$, and half-life. The Interacting Shell Model, which best fits our data, indicates a half-life for this decay at $T_{1/2}=(5.26\pm 0.06)\times 10^{14}$,yr.

   nucl-exnucl-thPRL(2024)·14 citations
4. 04*

   The Jefferson Lab positron physics program

   Eric Voutier🇫🇷

   The Ce${}^{+}$BAF project at the Thomas Jefferson National Accelerator Facility intends to develop over the coming years a high-duty cycle, high intensity, and high polarization positron beam to serve a unique Nuclear Physics experimental program. It generically comprises the study of the effects of the two- and multi-photon exchange mechanisms, the investigation of the nuclear structure at the nucleonic and partonic scales, and tests of the standard model of particle physics and interactions. This proceedings illustrates this physics program through specific examples and presents the Ce${}^{+}$BAF positron injector concept.

   nucl-exhep-exEPJ Web Conf.(2024)·3 citations
5. 05*

   Anisotropic flow, flow fluctuation and flow decorrelation in relativistic heavy-ion collisions: the roles of sub-nucleon structure and shear viscosity

   Jie Zhu🇨🇳 · Xiang-Yu Wu🇨🇦 · Guang-You Qin🇨🇳

   We study the transverse momentum ($p_T$) differential anisotropic flow and flow fluctuation in Pb+Pb collisions at $\sqrt{s_{NN}}$=5.02 TeV at the LHC. A (3+1)-dimensional CLVisc hydrodynamics framework with fluctuating TRENTO (or AMPT) initial conditions is utilized to simulate the space-time evolution of the quark-gluon plasma (QGP) medium. The effects of shear viscosity and the sub-nucleon structure on anisotropic flow and flow fluctuation are analyzed. Our result shows that shear viscosity tends to suppress both flow coefficients ($v_2\{2\}$, $v_2\{4\}$, $⟨v_2⟩$) and flow fluctuation (${\sigma }_{v_2}$) due to its smearing effect on local density fluctuation. The flow coefficients appear to be insensitive to the sub-nucleon structure, whereas for flow fluctuation ${\sigma }_{v_2}$, it tends to be suppressed by the sub-nucleon structure in central collisions but enhanced in peripheral collisions. After taking into account the sub-nucleon structure effect, our numerical result can quantitatively describe the relative flow fluctuations ($v_2\{4\}/v_2\{2\}$, $F(v_2)$) measured by the ALICE Collaboration at the LHC. We further investigate the effects of shear viscosity, sub-nucleon structure and initial condition model on the flow angle and flow magnitude decorrelations ($A_2^f$, $M_2^f$) using the four-particle correlation method. We find that the flow decorrelation effect is typically stronger in central collisions than in peripheral collisions. The flow angle decorrelation is found to be insensitive to the shear viscosity and sub-nucleon structure, whereas the flow magnitude decorrelation shows quite different behavior when using TRENTO or AMPT initial condition model. Our study sheds light on the anisotropic flow, transport properties and initial structure of the QGP created in high-energy nuclear collisions.

   ↳ hep-phnucl-exnucl-thCPC(2025)·13 citations
6. 06*

   Using the Transition-Density Formalism in the First Computation of 4He Compton Scattering

   Harald W. Griesshammer (George Washington U.)🇺🇸 · Junjie Liao (George Washington U.)🇺🇸 · Judith A. McGovern (U. of Manchester)🇬🇧 · Andreas Nogga (FZ Jülich)🇩🇪 · Daniel R. Phillips (Ohio U.)🇺🇸

   The method and results of the first theory description of 4He Compton scattering at nuclear energies is presented, with a focus on figures. An upcoming publication [1] contains details and a comprehensive list of references.

   ↳ nucl-thnucl-exEPJ Web Conf.(2024)·1 citation
7. 07*

   Exploring the compactness of $\alpha$ cluster in ${}^{16}$O nuclei with relativistic ${}^{16}$O+${}^{16}$O collisions

   Yuanyuan Wang · Shujun Zhao🇨🇳 · Boxing Cao · Hao-jie Xu🇨🇳 · Huichao Song🇨🇳

   Probing the $\alpha$ cluster of ${}^{16}$O with the relativistic ${}^{16}$O+${}^{16}$O collisions has raised great interest in the heavy ion community. However, the effects of the $\alpha$ cluster on the soft hadron observables vary largely among different studies. In this paper, we explain the differences by the compactness of the $\alpha$ cluster in oxygen, using iEBE-VISHNU hydrodynamic simulations with different initial state $\alpha$ cluster configurations. We also find several observables, such as the intensive skewness of the $[p_{\mathrm{T}}]$ correlator ${\Gamma }_{p_{\mathrm{T}}}$, the harmonic flows $v_2\{2\}$, $v_2\{4\}$, $v_3\{2\}$, and the $v_n^2-\delta [p_{\mathrm{T}}]$ correlations $\rho (v_2^2,[p_{\mathrm{T}}])$, $\rho (v_3^2,[p_{\mathrm{T}}])$ in ${}^{16}$O+${}^{16}$O collisions are sensitive to the compactness of the $\alpha$ cluster in the colliding nuclei, which can be used to constrain the configurations of ${}^{16}$O in the future. Our study serves as an important step toward the quantitative exploration of the $\alpha$ cluster configuration in the light nuclei with relativistic heavy ion collisions.

   ↳ nucl-thnucl-exPRC(2024)·45 citations
8. 08*

   Photoproduction of the $X(3872)$ beyond vector meson dominance: the open-charm coupled-channel mechanism

   Xiong-Hui Cao🇨🇳 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳

   Hidden-charm exotic hadrons will be searched for and investigated at future electron-ion colliders. For instance, the $X(3872)$ can be produced through the exclusive process $\gamma p\to X(3872)p$. The vector meson dominance model has been commonly employed in estimating the cross sections of such processes. However, the coupled-channel production mechanism through open-charm meson-baryon intermediate states may play a crucial role. To assess the significance of such contributions, we estimate the cross section of the $\gamma p\to X(3872)p$ reaction assuming the coupled-channel mechanism. For energies near the threshold, the total cross section is predicted to be of tens of nanobarns for $\gamma p\to X(3872)p$, which can be measured at future experimental facilities. Furthermore, the open-charm coupled-channel mechanism leads to a distinct line shape of the total cross section that can be utilized to reveal the production dynamics.

   ↳ hep-phhep-exnucl-exnucl-thJ.Phys.G(2024)·10 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.