Mon·Dec 15, 2025Monday·December 15, 2025

1. 01*

   Characterization of CRYO ASIC for charge readout in the nEXO experiment

   Z. Li🇺🇸 · M. Yu🇺🇸 · E. Angelico🇺🇸 · A. Atencio🇺🇸 · A. Gupta🇺🇸 · P. Knauss🇺🇸 · A. Pena-Perez🇺🇸 · B. G. Lenardo🇺🇸 · P. Acharya🇺🇸 · A. Amy🇫🇷 · A. Anker🇺🇸 · I. J. Arnquist🇺🇸 and 132 other authors

   nEXO is a proposed next-generation experiment searching for the neutrinoless double beta decay of ${}^{136}$Xe using a tonne-scale liquid xenon (LXe) time projection chamber (TPC). To image the ionization signals from events in the liquid xenon, the detector will employ metallized fused-silica charge collection tiles instrumented with cryogenic application-specific integrated circuits (ASICs), referred to as CRYO ASIC, which are designed to operate directly in LXe to minimize input capacitance and pick-up noise. Here we present the performance of the CRYO ASIC mounted on an auxiliary printed circuit board and evaluated both in a cryogenic environmental chamber and in a dedicated LXe test stand. We demonstrate that the ASICs achieve the desired performance at liquid xenon temperatures, showing a gain stability better than 0.2% over 24-hour operation and reliable in-situ calibration using an on-chip pulser. In the LXe test stand, we show that boiling caused by the chip heat dissipation can be mitigated by operating the system above ~0.1 MPa. The in-LXe noise measured agrees with simulation, which indicates it the $150e^{-}$ design requirement can be satisfied. These results establish CRYO ASIC as a viable low-noise in-LXe charge readout solution for nEXO.

   ↳ physics.ins-detnucl-ex0 citations
2. 02*

   The $B(E2)$ anomaly: Evidence for a low-lying mixed-symmetry collective excitation mode

   Bo Cederwall🇸🇪 · Chong Qi🇸🇪

   Exceptionally low values of the ratio of electric quadrupole transition rates, $B_{4/2}\equiv B(E2;4_1^{+}\to 2_1^{+})/B(E2;2_1^{+}\to 0_{\mathrm{gs}}^{+})<1$, have been observed in neutron-deficient nuclei near $N\approx 94$ (W, Os, Pt) and $N\approx 62$ (Te, Xe) with few and comparable numbers of valence nucleons outside closed shells. Remarkably, the suppressed $B_{4/2}$ ratios coincide with low-lying energy level patterns characteristic of collective motion. Standard approaches, including large-scale shell model, collective models, and density functional theory, fail to reproduce this behavior, commonly referred to as the $B4/2$ (or $B(E2)$) anomaly. Recent work has reproduced the effect in selected Pt and Os isotopes via mapping a triaxial rotor Hamiltonian onto the interacting boson model (IBM), attributing it to triaxial rotational motion. However, this interpretation is unexpected as collectivity typically emerges first through vibrational modes with increasing valence nucleon number along isotopic chains. Here, we address this discrepancy using an extended IBM Hamiltonian across nuclei exhibiting the anomaly, benchmarked against large-scale shell model calculations, and propose that the $B(E2)$ anomaly arises from a low-lying mixed-symmetry collective mode that bridges single-particle and collective dynamics.

   ↳ nucl-thnucl-exEPJA(2026)·0 citations
3. 03*

   From DGLAP to Sudakov: Precision Predictions for Energy-Energy Correlators

   Max Jaarsma🇳🇱 · Yibei Li🇩🇪 · Ian Moult🇺🇸 · Wouter J. Waalewijn🇳🇱 · Hua Xing Zhu🇨🇳

   Correlations in the distribution of energy produced in collider experiments provide a snapshot of the microscopic dynamics of QCD, and its evolution from asymptotically free quarks and gluons, to confined hadrons. There has recently been considerable progress in the interpretation and precision calculation of these correlations, using a specific class of observables called energy correlators (EECs). These observables are most cleanly studied in $e^{+}{e}^{-}$ collisions, where they can be measured over their full angular range. Of particular interest are kinematic limits of the correlator, both collinear, and back-to-back, where the correlator exhibits scaling behaviors governed by specific operators in QCD. Resolving these scalings requires measurements with exceptional angular resolution, which can be achieved by performing measurements on tracks (charged particles). In this paper we perform the first calculation of the track-based EEC over its entire kinematic range, achieving a record precision of of NNLL (collinear) + NNLO (fixed order) + NNNNLL (back-to-back) for the track-based EEC, and additionally incorporate the leading non-perturbative corrections and their resummation, including the Collins-Soper kernel computed using lattice QCD. We describe the breadth of physics probed by this observable, and highlight the impact of different components of our factorization theorem on the final distribution. Combined with recent measurements of the track-based EEC with archival LEP data, our calculation initiates the precision study of track-based observables at LEP, which will lead to new insights into the dynamics of QCD, and the precision extraction of its underlying parameters.

   ↳ hep-phhep-exhep-thnucl-ex+124 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.