Fri·Dec 20, 2024Friday·December 20, 2024

1. 01*

   $\beta$-Decay Spectroscopy of ${}^{23}$Al

   Itay Goldberg

   This research explores the beta decay of the proton-rich nucleus 23Al. The nucleus was generated at the National Superconducting Cyclotron Laboratory (NSCL) through projectile fragmentation, utilizing a primary beam of 36Ar ions directed at a 9Be target. Simultaneous measurements of proton emission and gamma rays were conducted using the GADGET detection system. The decay paths were carefully analyzed through beta-gamma , proton-gamma , and gamma -gamma coincidences, leading to the construction of a complete decay scheme for 23Al. The absolute beta branching ratios were determined, and log-ft values were calculated for transitions to 23Mg states. Additionally, proton branching ratios and the most precise half-life measurement of 23Al to date were obtained. The findings include the identification of 19 new gamma rays and the discovery of a new beta-delayed proton transition populating the third excited state of 22Na.

   nucl-ex0 citations
2. 02*

   Probing Solar Heavy Neutrinos with Heliospheric Electrons

   Marco Drewes🇧🇪 · Jan Heisig🇩🇪 · Valentin Weber🇧🇪

   We search for an excess of electrons and positrons in the interplanetary space from the decays of heavy neutrinos produced in nuclear reactions in the Sun. Using measurements of the electron spectra in the MeV range from the Ulysses and SOHO satellites, we report the strongest direct upper bound to date on the mixing between heavy neutral leptons with MeV masses and electron neutrinos, reaching $U_e^2\simeq 10^{-6}$ at $M_N=10$MeV. Our sensitivity is predominantly constrained by the uncertainties in the propagation of electrons and positrons, particularly the diffusion coefficient in the inner Solar System, as well as the uncertainties in the astrophysical background. Enhancing our understanding of either of these factors could lead to a significant improvement in sensitivity.

   ↳ astro-ph.HEastro-ph.SRhep-phnucl-exPRD(2025)·4 citations
3. 03*

   Thermal dilepton polarization and dynamics of the QCD plasma in relativistic heavy-ion collisions

   Xiang-Yu Wu🇨🇦 · Han Gao🇨🇦 · Bailey Forster🇨🇦 · Charles Gale🇨🇦 · Greg Jackson🇫🇷 · Sangyong Jeon🇨🇦

   We present the first theoretical study of the polarization of lepton pairs produced in $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV Pb+Pb collisions at the LHC, using next-to-leading order (NLO) dilepton emission rates. These calculations employ a multi-stage framework to simulate the evolution of relativistic heavy-ion collisions, and to explore the sensitivity of polarization to early times. It is found that the intermediate invariant-mass dileptons are indeed probes of the thermal equilibration process, and go beyond the reach of hadronic observables. We compute the polarization anisotropy coefficient obtained with LO dilepton rates, and show that the LO and NLO results differ radically, both in trend and in magnitude, at low and intermediate lepton pair invariant masses.

   ↳ nucl-thhep-phnucl-exPRL(2025)·14 citations
4. 04*

   Measurement of the energy-energy correlator in the back-to-back limit using the archived ALEPH $e^{+}{e}^{-}$ data at 91.2 GeV

   Hannah Bossi🇺🇸 · Austin Baty🇺🇸 · Yi Chen🇺🇸 · Yu-Chen Chen🇺🇸 · Gian-Michele Innocenti🇺🇸 · Marcello Maggi🇮🇹 · Chris McGinn🇺🇸 · Yen-Jie Lee🇺🇸

   Recently, energy-energy correlators (EECs) have garnered renewed interest for studying hadronic collisions at the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC). EEC measurements within jets provide a clear scale separation, facilitating the study of both perturbative and non-perturbative Quantum Chromodynamics (QCD) in the collinear limit. These proceedings present recent EEC results from the archived ALEPH $e^{+}{e}^{-}$ data taken at LEP at $\sqrt{s}$ = 91.2 GeV. In $e^{+}{e}^{-}$ collisions, perturbative and non-perturbative QCD can be studied with EECs in both the collinear limit using jets and the back-to-back limit using all particles as well as the transition between these two regimes. Comparisons of these results to generators and future extensions of this work will also be discussed.

   ↳ hep-exnucl-exPoS(2025)·11 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.