Tue·May 6, 2025Tuesday·May 6, 2025

1. 01*

   ${}^{28}$Al Half-life Measurement and the negative mirror asymmetry between the ${}^{28}$Al(${\beta }^{-}$)${}^{28m}$Si and ${}^{28}$P(${\beta }^{+}$)${}^{28m}$Si decays

   B. Liu · M. Brodeur🇺🇸 · D.W. Bardayan · F.D. Becchetti · C. Boomershine · D.P. Burdette🇺🇸 · L. Caves · O. Olivas-Gomez · S.L. Henderson · J.J. Kolata🇺🇸 · J. Long🇬🇧 · A.D. Nelson and 3 other authors

   In the past, the mirror asymmetry parameter has been proposed as a probing mechanism for the presence of beyond the Standard Model second-class currents in nuclear beta decay transitions. However, this was hindered by large uncertainties in the required nuclear structure correction terms. Recently, a new calculation of these corrections attempted, but could not fully explain the negative mirror asymmetry between the ${}^{28}$Al(${\beta }^{-}$)${}^{28m}$Si and ${}^{28}$P(${\beta }^{+}$)${}^{28m}$Si decays. To put the mirror asymmetry parameter on a more solid footing, the half-life of ${}^{28}$Al was measured for the first time using a radioactive ion beam at the Nuclear Science Laboratory of the University of Notre Dame. The new result, $t_{1/2}=$134.432(34) s, is consistent with most of the past data except for one highly discrepant measurement. The new mirror asymmetry parameter of -3.5(10)$\%$ obtained still does not agree with nuclear structure calculations.

   nucl-exPRC(2025)·0 citations
2. 02*

   The NA60+ experiment at SPS

   Alexander Milov🇮🇱

   A new apparatus, NA60+, is proposed for measuring muon pairs in the center-of-mass region from 5 to 17 GeV at CERN SPS in various collisional systems from Pb+Pb and down to $p$+Be. The physics scope of the new detector will cover topics from the measurement of thermal radiation coming from the hot and dense medium to chiral symmetry restoration, strangeness, and charm production. The proposed detector consists of a vertex spectrometer based on novel technology, allowing the production of large silicon sensors and a large-acceptance muon spectrometer based on gaseous detectors. With its high beam intensity, the new apparatus provides access to rare observables that have been scarcely studied until now. The new detector will come into operation after the Long Shutdown 3 of the LHC (past 2029) and is aimed at the first data-taking with Pb and proton beams. In this contribution, we review the project and recent R\&D effort, including the technical aspects and the studies of the physics performances for the observables.

   nucl-exphysics.ins-detEPJ Web Conf.(2025)·0 citations
3. 03*

   Uranium and Plutonium antineutrino spectra taken by summation method used to fit experimentally measured reactor antineutrino spectrum

   Valery Sinev🇷🇺 · Pavel Alzhev · Svetlana Ingerman🇷🇺 · Petr Naumov · Artemiy Vlasenko🇷🇺

   Antineutrino spectra of fissile isotopes calculated using summation method being used to fit experimental spectra got in several experiments. Summation method was used with the possibility of changing individual spectrum shape of unknown fragments. Found spectra conform to all experiments and reproduce with the best accuracy measured inverse beta decay cross sections.

   nucl-exhep-ex0 citations
4. 04*

   Pre-study of a Li2MoO4 based bolometer for 100Mo neutrinoless double beta decay experiment in China

   Deyong Duan🇨🇳 · Mingxuan Xue🇨🇳 · Kangkang Zhao🇨🇳 · Taiyuan Liu🇨🇳 · Haiping Peng🇨🇳 · Jiaxuan Cao🇨🇳 · Long Ma🇨🇳 · Liang Chen🇨🇳 · Hui Yuan🇨🇳 · Qing Lin🇨🇳 · Zizong Xua · Xiaolian Wang🇨🇳

   The cryogenic phonon scintillating bolometer is a promising and extremely attractive option to search for the nuclide neutrinoless double beta decay. In this paper, a pre-study of bolometer based on Li2MoO4 (LMO) crystal is presented, in which the properties of the LMO crystal at the low temperature, including scintillation characteristics and specific heat, are investigated in detail. The excitation spectrum and light yield are measured from the room temperature down to 10 K, and heat capacity is measured down to temperature of O(200) mK. Furthermore, a (2 cm)3 cubic LMO based bolometer is manufactured and tested at ultra-low mK-level temperature in a ground-above cryostat platform, and a good energy resolution is achieved. The studies laid a foundation to manufacture the bolometer detector in China and conduct neutrinoless double beta decay research at the China Jinping Underground Laborator

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2026)·1 citation
5. 05*

   Tilted-axis-cranking covariant density functional theory for the high-spin spectroscopy in ${}^{69}$Ga

   Y. P. Wang · Y. K. Wang · P. W. Zhao🇨🇳

   The tilted-axis-cranking covariant density functional theory is applied to investigate the three newly-observed positive-parity bands SI, SII, and SIII in ${}^{69}$Ga. The energy spectra and angular momenta are calculated and compared with the experimental data. For the yrast band SI, pairing correlations play a crucial role for the states with spin $I\le 23/2\hslash$. The bands SII and SIII are suggested to be signature partner bands with positive and negative signatures, respectively. The transition probabilities $B(E2)$ for these bands are predicted, and await further experimental verification. By analyzing the angular momentum alignments microscopicly, it is revealed that the $g_{9/2}$ protons and neutrons play an important role in the description of the collective structure of ${}^{69}$Ga.

   ↳ nucl-thnucl-exCPC(2026)·1 citation
6. 06*

   Probing $\Lambda$ potential via its $v_2$ flow in hypernuclei-induced reaction

   Gao-Chan Yong🇨🇳

   The hyperon potential, particularly its behavior at high densities, is crucial for resolving the ``hyperon puzzle'' in neutron stars and for advancing our understanding of the strong interactions between strange and non-strange particles in high baryon density environments. Using the hadronic transport model AMPT-HC, hypernucleus-nucleus collision is studied. It is found that at beam energies below the threshold for hyperon production, the hyperon elliptic flow exhibits noticeable asymmetry between the positive and negative rapidity regions and is sensitive to the strength of the hyperon potential, especially in the large negative rapidity region. One can extract the hyperon potential approximately twice the saturation density based on the hyperon elliptic flow in the negative rapidity region, and the hyperon potential around the saturation density based on the hyperon elliptic flow in the positive rapidity region.

   ↳ nucl-thnucl-exPLB(2025)·2 citations
7. 07*

   Improving Positron Lifetime Spectra Quality by Suppressing Corrupted Coincidences via Pulse-Height Spectrum Window Adjustments

   Dominik Boras · Danny Petschke · Torsten Staab

   Positron Annihilation Lifetime Spectroscopy (PALS) is a powerful technique for detecting microstructural defects in various material classes. In a commonly used 180{\deg} detector configuration equipped with plastic scintillators, measurement accuracy is mainly affected by simultaneous detection of 1275 keV and 511 keV gamma quanta in the same detector. This study introduces an optimization approach that significantly improves spectra quality without requiring hardware modifications. By systematically adjusting the upper threshold of the start window in the Pulse Height Spectrum (PHS), this method effectively reduces unwanted 1275/511 piled-up events. Experimental validation with high purity aluminium samples demonstrates that lowering this threshold effectively suppresses corrupted coincidences, yielding extracted characteristic lifetimes closer to those from a 90{\deg} configuration. While a reduced upper threshold slightly broadens the instrument response function (IRF) due to an effectively reduced number of scintillation photons, the overall impact on timing resolution remains negligible. This approach enhances the reliability of PALS measurements while still preserving the benefits of a 180{\deg} configuration, i.e. high solid-angle efficiency.

   ↳ physics.ins-detnucl-exJINST(2025)·0 citations
8. 08*

   Transverse momentum fluctuations as a probe of thermalization and collective dynamics of QGP

   Rupam Samanta🇵🇱 · Tribhuban Parida🇮🇳

   We study fluctuations of mean transverse momentum per particle ($[p_T]$) in ultrarelativistic heavy-ion collisions. We show that the steep fall in the variance of transverse momentum fluctuation in ultracentral Pb+Pb collision serves as a natural consequence of the thermalization of the QGP medium. We study the correlation between the spectra and $[p_T]$ which maps these fluctuations differentially and dubbed as $v_0(p_T)$. We highlight the importance of $v_0(p_T)$ showing that it plays similar role as anisotropic flow when probing the collective nature of QGP.

   ↳ nucl-thnucl-exJ.Subatomic Part.Cosmol.(2025)·1 citation
9. 09*

   Dynamical coupled-channel models for hadron dynamics

   Michael Döring🇺🇸 · Johann Haidenbauer🇩🇪 · Maxim Mai🇺🇸 · Toru Sato🇯🇵

   Dynamical coupled-channel (DCC) approaches parametrize the interactions and dynamics of two and more hadrons and their response to different electroweak probes. The inclusion of unitarity, three-body channels, and other properties from scattering theory allows for a reliable extraction of resonance spectra and their properties from data. We review the formalism and application of the ANL-Osaka, the Juelich-Bonn-Washington, and other DCC approaches in the context of light baryon resonances from meson, (virtual) photon, and neutrino-induced reactions, as well as production reactions, strange baryons, light mesons, heavy meson systems, exotics, and baryon-baryon interactions. Finally, we also provide a connection of the formalism to study finite-volume spectra obtained in Lattice QCD, and review applications involving modern statistical and machine learning tools.

   ↳ nucl-thhep-lathep-phnucl-exPPNP(2026)·45 citations
10. 10*

    On Robust $\beta$-Spectra Shape Parameter Extraction

    B. C. Rasco🇺🇸 · T. Gray🇺🇸 · T. Ruland🇺🇸

    Experimental extraction of $\beta$-shape functions, C(W), is challenging. Comparing different experimental $\beta$-shapes to each other and to those predicted by theory in a consistent manner is difficult. This difficulty is compounded when different parameterizations of the $\beta$-shape function are used. Usually some form of a power polynomial of the total electron energy is chosen for this parametrization. This choice results in extracted coefficients that are highly correlated, with their physical meaning and numerical value dependent on the order of polynomial chosen. This is true for both theoretical and experimental coefficients, and leads to challenges when comparing coefficients from polynomials of different orders. Accurately representing the highly correlated uncertainties is difficult and subtle. These issues impact the underlying physical interpretation of shape function parameters. We suggest an alternative approach based on orthogonal polynomials. Orthogonal polynomials offer more stable coefficient extraction which is less dependent on the order of the polynomial, allow for easier comparison between theory and experimental coefficients from polynomials of different orders, and offer some observations on simple physical meaning and on the statistical limits of the extracted coefficients.

    ↳ physics.comp-phnucl-exnucl-thphysics.chem-phPRC(2026)·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.