Tue·May 28, 2024Tuesday·May 28, 2024

1. 01*

   Searches for new physics below twice the electron mass with GERDA

   GERDA Collaboration: M. Agostini🇬🇧 · A. Alexander🇬🇧 · G. R. Araujo🇨🇭 · A. M. Bakalyarov🇷🇺 · M. Balata🇮🇹 · I. Barabanov🇷🇺 · L. Baudis🇨🇭 · C. Bauer🇩🇪 · S. Belogurov🇷🇺 · A. Bettini🇮🇹 · L. Bezrukov🇷🇺 · V. Biancacci🇮🇹 and 98 other authors

   A search for full energy depositions from bosonic keV-scale dark matter candidates of masses between 65 keV and 1021 keV has been performed with data collected during Phase II of the GERmanium Detector Array (GERDA) experiment. Our analysis includes direct dark matter absorption as well as dark Compton scattering. With a total exposure of 105.5 kg yr, no evidence for a signal above the background has been observed. The resulting exclusion limits deduced with either Bayesian or Frequentist statistics are the most stringent direct constraints in the major part of the 140-1021 keV mass range. As an example, at a mass of 150 keV the dimensionless coupling of dark photons and axion-like particles to electrons has been constrained to $\alpha$'/$\alpha$ < 8.7x10${}^{-24}$ and g${}_{ae}$ < 3.3x10${}^{-12}$ at 90% credible interval (CI), respectively. Additionally, a search for peak-like signals from beyond the Standard Model decays of nucleons and electrons is performed. We find for the inclusive decay of a single neutron in ${}^{76}$Ge a lower lifetime limit of ${\tau }_n$ > 1.5x10${}^{24}$ yr and for a proton ${\tau }_p$ > 1.3x10${}^{24}$ yr at 90% CI. For the electron decay e${}^{-}\to {\nu }_e\gamma$ a lower limit of ${\tau }_e$ > 5.4x10${}^{25}$ yr at 90% CI has been determined.

   nucl-exhep-exEPJC(2024)·5 citations
2. 02*

   Monte-Carlo Study Of Higher-Order Cumulants of Net-Particle Distributions in $p+p$ Collisions at $\sqrt{s}$ = 13 TeV

   Abdussamad M🇮🇳 · Rahul Verma🇮🇳 · Nirbhay Kumar Behera🇮🇳 · Sadhana Dash🇮🇳 · Basanta Kumar Nandi🇮🇳

   Measurement of higher order cumulants of the distributions of conserved quantities, like net-charge, net-baryon and net-strangeness in heavy-ion collisions, is proposed as a sensitive tool to determine the freeze-out parameters and the nature of phase transitions at the LHC energies. Baseline measurements for heavy-ion collisions are essential to understand the experimental measurements. Recently, several experimental observations have shown some QGP-like scenarios in small systems (pp collisions). We report the first Monte-Carlo study of the measurements of cumulants and their ratios for net-charge, net-hadron, net-kaon, net-baryon, and net-proton distributions in pp collisions at $\sqrt{s}$=13 TeV using pQCD models like Pythia8 and Herwig. We also discuss the effect of different particle production mechanisms on the higher-order cumulants. This simulation study will serve as a baseline for future measurements at the LHC. Furthermore, it will shed more light on the measurement of cumulants and the connection between small systems and heavy-ion collisions at the LHC.

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

   Jet substructure measurements in heavy-ion collisions

   Robert Vertesi (for the ATLAS, CMS, and ALICE Collaborations)🇭🇺

   Jet substructure in heavy-ion collisions is a rapidly evolving area with lots of intriguing new measurements. This contribution presents a selection of recent jet-substructure measurements from experiments at the LHC, in particular, soft-drop groomed radii of jets and reclustered large-radius jets from ATLAS, jet axis difference and generalized jet angularities from ALICE, as well as dijet shapes and b-jet shapes from the CMS experiment.

   nucl-exhep-phnucl-thInt.J.Mod.Phys.A(2025)·5 citations
4. 04*

   Isoscalar, isovector and orbital contributions in $M1$ transitions from analogous $M1$ and Gamow-Teller transitions in $T=\frac{1}{2}$ mirror nuclei

   Subhrajit Sahoo🇮🇳 · Praveen C. Srivastava🇮🇳

   The isoscalar and isovector components and their contributions to $M1$ transitions are discussed in the odd-$A$, $T=1/2$ mirror nuclei with mass number ranging from $A=23$ to 37. The orbital contributions in various $M1$ transitions and ground state magnetic moments are calculated by comparing analogous $M1$ and Gamow-Teller transitions between mirror pairs. The orbital contributions in different $M1$ transitions are explained on the basis of configurations of the initial and final states involved. In magnetic moments, the orbital contributions are found to be dependent on the deformation and single-particle nature of the states. All the $T=1/2$ mirror pairs are studied using isospin non-conserving interaction. The results are also compared with predictions from \textit{ab initio} effective interaction derived from realistic nuclear forces.

   ↳ nucl-thnucl-exPRC(2024)·1 citation
5. 05*

   Examining LEGEND-1000 cosmogenic neutron backgrounds in Geant4 and MCNP

   C.J. Barton🇺🇸 · W. Xu🇺🇸 · S.R. Elliott🇺🇸 · R. Massarczyk🇺🇸

   For next-generation neutrinoless double beta decay experiments, extremely low backgrounds are necessary. An understanding of in-situ cosmogenic backgrounds is critical to the design effort. In-situ cosmogenic backgrounds impose a depth requirement and especially impact the choice of host laboratory. Often, simulations are used to understand background effects, and these simulations can have large uncertainties. One way to characterize the systematic uncertainties is to compare unalike simulation programs. In this paper, a suite of neutron simulations with identical geometries and starting parameters have been performed with Geant4 and MCNP, using geometries relevant to the LEGEND-1000 experiment. This study is an important step in gauging the uncertainties of simulations-based estimates. To reduce project risks associated with simulation uncertainties, a novel alternative shield of methane-doped liquid argon is considered in this paper for LEGEND-1000, which could achieve large background reduction without requiring significant modification to the baseline design.

   ↳ physics.ins-detnucl-exJINST(2024)·1 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.