Wed·May 1, 2024Wednesday·May 1, 2024

1. 01*

   Report from the Workshop on Xenon Detector $0\nu \beta \beta$ Searches: Steps Towards the Kilotonne Scale

   A. Anker🇺🇸 · A. Avasthi🇩🇪 · M.Brodeur🇺🇸 · T. Brunner🇨🇦 · N.K. Byrnes🇺🇸 · N.R. Catarineu🇺🇸 · A. Cottle🇬🇧 · P. Englezos🇺🇸 · W. Fairbank🇺🇸 · D. González Díaz🇪🇸 · R. Guenette🇬🇧 · S.J. Haselschwardt🇺🇸 and 26 other authors

   These proceedings summarize the program and discussions of the ``Workshop on Xenon Detector $0\nu \beta \beta$ Searches: Steps Towards the Kilotonne Scale'' held on October 25-27 2023 at SLAC National Accelerator Laboratory. This workshop brought together experts from the communities of neutrinoless double-beta decay and dark matter detection, to discuss paths forward for the realization of monolithic experiments with xenon approaching the kilotonne scale.

   nucl-ex5 citations
2. 02*

   Photoproduction of the {\Sigma}+ hyperon using linearly polarized photons with CLAS

   CLAS Collaboration: L. Clark · B. McKinnon · D.G. Ireland · D.I. Glazier · K. Livingston · D. Rönchen

   Background: Measurements of the polarization observables {\Sigma}, P, T, Ox, Oz for the reaction {\gamma}p {\rightarrow) KS0 {\Sigma}+ using a linearly polarized photon beam of energy 1.1 to 2.1 GeV are reported. Purpose: The measured data provide information on a channel that has not been studied extensively, but is required for a full coupled-channel analysis in the nucleon resonance region. Method: Observables have been simultaneously extracted using likelihood sampling with a Markov-Chain Monte- Carlo process. Results: Angular distributions in bins of photon energy E{\gamma} are produced for each polarization observable. T, Ox and Oz are first time measurements of these observables in this reaction. The extraction of {\Sigma} extends the energy range beyond a previous measurement. The measurement of P, the recoil polarization, is consistent with previous measurements. Conclusions: The measured data are shown to be significant enough to affect the estimation of the nucleon resonance parameters when fitted within a coupled-channels model.

   nucl-exPRC(2025)·7 citations
3. 03*

   CP Violation Problem

   Nicolai Popov (LMU)🇩🇪 · William J. Briscoe (GWU)🇺🇸 · Igor Strakovsky (GWU)🇺🇸

   The strong CP violation problem has a long history emanating from its discovery 60 years ago in the decay of neutral kaons and subsequent experimental and theoretical studies over several decades. We review herein experimental data that observe indirect CP violation of the order of $\sim 10^{-3}$, as well as the discovery of direct CP violation of the order of $\sim 10^{-6}$. Despite improved experimental methods over the past half a century, the original CP violation numbers have remained the same. Verification of the CP violation in the decay of charged kaons was also observed. Data reflecting CP violation in the decays of $B$ and $D$ mesons have become very important and are also discussed in this review. The question of CP violation only with the participation of $s\bar{s}$, $c\bar{c}$, and $b\bar{b}$ quarks in the framework of the Standard Model or beyond it and its small magnitude remains open.

   ↳ hep-phhep-exnucl-exnucl-thBraz.J.Phys.(2025)·0 citations
4. 04*

   Does the Electron EDM Preclude Electroweak Baryogenesis ?

   Yuan-Zhen Li🇨🇳 · Michael J. Ramsey-Musolf🇨🇳 · Jiang-Hao Yu🇨🇳

   Electroweak baryogenesis (EWBG) constitutes a theoretically compelling and experimentally testable mechanism for explaining the origin of the baryon asymmetry of the universe (BAU). New results for the electric dipole moment (EDM) of the electron place significant constraints on the beyond Standard Model CP-violation needed for successful EWBG. Using a specific model illustration, we show how new developments in EWBG quantum transport theory that include CP-violating sources first order in gradients imply more relaxed EDM constraints -- and thereby greater EWBG viability -- than implied by previous approximation formulations. We also illustrate how these developments enable a more realistic treatment of CP-conserving interactions that can also have a decisive impact on the predicted BAU.

   ↳ hep-phhep-exnucl-exnucl-thPhys.Lett.B 140503 (2026)·11 citations
5. 05*

   Dihadron helicity correlation in photon-nucleus collisions

   Zhao-Xuan Chen🇨🇳 · Hui Dong🇨🇳 · Shu-Yi Wei🇨🇳

   The helicity correlation of two back-to-back hadrons is a powerful tool that makes it possible to probe the longitudinal spin transfer, $G_{1L}$, in unpolarized hadronic collisions. In this work, we investigate the helicity correlation of back-to-back dihadrons produced in photon-nucleus collisions with both space-like and quasireal photons and explore its potential in understanding the flavor dependence of spin-dependent fragmentation functions. We present helicity amplitudes of partonic scatterings with both virtual and real photons and make numerical predictions for the dihadron helicity correlations at the future Electron Ion Collider experiment and the current RHIC/LHC ultra-peripheral collision experiment. Future experimental measurements can also illuminate the fragmentation function of circularly polarized gluons.

   ↳ hep-phhep-exnucl-exPRD(2024)·9 citations
6. 06*

   Impact of recent updates to neutrino oscillation parameters on the effective Majorana neutrino mass in 0$\nu \beta \beta$ Decay

   Dongming Mei🇺🇸 · Kunming Dong🇺🇸 · Austin Warren🇺🇸 · Sanjay Bhattarai🇺🇸

   We investigate how recent updates to neutrino oscillation parameters and the sum of neutrino masses influence the sensitivity of neutrinoless double-beta (0$\nu \beta \beta$) decay experiments. Incorporating the latest cosmological constraints on the sum of neutrino masses and laboratory measurements on oscillations, we determine the sum of neutrino masses for both the normal hierarchy (NH) and the inverted hierarchy (IH). Our analysis reveals a narrow range for the sum of neutrino masses, approximately 0.06 eV/c${}^2$ for NH and 0.102 eV/c${}^2$ for IH. Utilizing these constraints, we calculate the effective Majorana masses for both NH and IH scenarios, establishing the corresponding allowed regions. Importantly, we find that the minimum neutrino mass is non-zero, as constrained by the current oscillation parameters. Additionally, we estimate the half-life of 0$\nu \beta \beta$ decay using these effective Majorana masses for both NH and IH. Our results suggest that upcoming ton-scale experiments will comprehensively explore the IH scenario, while 100-ton-scale experiments will effectively probe the parameter space for the NH scenario, provided the background index can achieve 1 event/kton-year in the region of interest.

   ↳ hep-phnucl-exphysics.data-anPRD(2024)·6 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.