Tue·Aug 22, 2023Tuesday·August 22, 2023

1. 01*

   Final Results of GERDA on the Two-Neutrino Double-$\beta$ Decay Half-Life of ${}^{76}$Ge

   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 106 other authors

   We present the measurement of the two-neutrino double-$\beta$ decay rate of ${}^{76}$Ge performed with the GERDA Phase II experiment. With a subset of the entire GERDA exposure, 11.8 kg$\cdot$yr, the half-life of the process has been determined: $T_{1/2}^{2\nu }=(2.022\pm 0.018_{stat}\pm 0.038_{sys})\times 10^{21}$ yr. This is the most precise determination of the ${}^{76}$Ge two-neutrino double-$\beta$ decay half-life and one of the most precise measurements of a double-$\beta$ decay process. The relevant nuclear matrix element can be extracted: $M_{\text{eff}}^{2\nu }=(0.101\pm 0.001).$

   nucl-exPRL(2023)·40 citations
2. 02*

   Production of ${}^{180\mathrm{m}}$Hf in photoproton reaction ${}^{181}$Ta$(\gamma ,p)$ at energy $E_{\gamma \max }$ = 35-95 MeV

   I.S. Timchenko🇸🇰 · O.S. Deiev🇺🇦 · S.N. Olejnik🇺🇦 · S.M. Potin🇺🇦 · L.P. Korda🇺🇦 · V.A. Kushnir🇺🇦 · V.V. Mytrochenko🇺🇦 · S.A. Perezhogin🇺🇦 · A. Herzáň🇸🇰

   The production of the ${}^{180\mathrm{m}}\mathrm{Hf}$ nuclei in the photoproton reaction ${}^{181}\mathrm{Ta}(\gamma ,p)$ was studied at end-point bremsstrahlung energies $E_{\gamma \max }$ = 35-95 MeV. The experiment was performed at the electron linear accelerator LUE-40 NSC KIPT with the use of the $\gamma$ activation and off-line $\gamma$-ray spectroscopy. The experimental values of the bremsstrahlung flux-averaged cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{m}}$ for the ${}^{181}\mathrm{Ta}(\gamma ,p{)}^{180\mathrm{m}}\mathrm{Hf}$ reaction were determined, and at $E_{\gamma \max }>55$ MeV obtained for the first time. The measured values, also as the literature data, are significantly exceed the theoretical flux-averaged cross-sections $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{th}}$. The $⟨\sigma (E_{\gamma \max }){⟩}_{\mathrm{th}}$ values were calculated using the cross-section $\sigma (E)$ computed with the TALYS1.95 code for six different level density models. A comparative analysis of the calculated total cross-sections for the reactions ${}^{181}\mathrm{Ta}(\gamma ,p{)}^{180}\mathrm{Hf}$ and ${}^{181}\mathrm{Ta}(\gamma ,n{)}^{180}\mathrm{Ta}$ was performed. It was shown that the photoproton $(\gamma ,p)$ to photoneutron $(\gamma ,n)$ strength ratio is consistent with the estimates based on the isospin selection rules and the value from the $(e,e^{\prime }p)$ experiment.

   nucl-exEPJA(2023)·6 citations
3. 03*

   Hadronization mechanisms (via heavy-flavour hadrons): Experiment

   Andrea Rossi🇮🇹

   The formation of hadrons is a fundamental process in nature that can be investigated at particle colliders. Given their large mass, heavy quarks (charm and beauty) are produced only in initial hard-scatterings, prior to hadronisation, which determines instead the relative abundances and the kinematics of the various heavy-flavour hadron species. As several recent findings demonstrate, with \ee collisions as a "vacuum-like" reference at one extreme, and central AA as a dense, extended-size system characterised by flow and local equilibrium at the opposite extreme, different collision systems offer a lever arm that can be exploited to probe with a range of heavy-flavour hadron species the onset of various hadronisation processes. In these proceedings, a selection of the experimental results related to heavy-flavour hadronisation shown for the first time at the Hard Probes 2023 conference is presented together with some of the most important ones of the last years. The focus is on open-heavy flavour measurements. The comparison with model predictions and connections among the results in \ee, proton--proton, proton--nucleus, nucleus--nucleus collisions are discussed.

   ↳ hep-exnucl-exPoS(2024)·4 citations
4. 04*

   Modeling Backward-Angle ($u$-channel) Virtual Compton Scattering at an Electron-Ion Collider

   Zachary Sweger🇺🇸 · Spencer R. Klein🇺🇸 · Yuanjing Ji🇺🇸 · Minjung Kim🇺🇸 · Saeahram Yoo🇺🇸 · Ziyuan Zeng🇨🇳 · Daniel Cebra🇺🇸 · Xin Dong🇺🇸

   High-energy backward ($u$-channel) reactions can involve very large momentum transfers to the target baryons, shifting them by many units of rapidity. These reactions are difficult to understand in conventional models in which baryon number is carried by the valence quarks. Backward Compton scattering is an especially attractive experimental target, because of its simple final state. There is currently limited data on this process, and that data is at low center-of-mass energies. In this paper, we examine the prospects for studying backward Compton scattering at the future Electron-Ion Collider (EIC). We model the cross-section and kinematics using the limited data on backward Compton scattering and backward meson production, and then simulate Compton scattering at EIC energies, in a simple model of the ePIC detector. Generally, the proton is scattered toward mid-rapidity, while the produced photon is in the far-forward region, visible in a Zero Degree Calorimeter (ZDC). We show that the background from backward ${\pi }^0$ production can be rejected using a high-resolution, well-segmented ZDC.

   ↳ hep-phnucl-exnucl-thPRC(2023)·6 citations
5. 05*

   A novel method for calculating Bose-Einstein correlation functions with Coulomb final-state interaction

   Márton Nagy🇭🇺 · Aletta Purzsa🇭🇺 · Máté Csanád🇭🇺 · Dániel Kincses🇭🇺

   Measurements of Bose-Einstein correlations played a crucial role in the discovery and the subsequent detailed exploration of the Quark-Gluon-Plasma (QGP) created in high-energy collisions of heavy nuclei. Such measurements gave rise to femtoscopy, a flourishing sub-field of high-energy physics, and there are important new directions to explore and discoveries to be made in the near future. One of these important current topics is the precise investigation of the shape of the correlation functions utilizing Lévy-stable sources. In this paper, we present a novel method of calculating the shape of the two-particle correlation functions, including the Coulomb final-state interaction. This method relies on an exact calculation of a large part of the necessary integrals of the Coulomb wave function and can be utilized to calculate the correlation function for any source function with an easily accessible Fourier transform. In this way, it is eminently applicable to Lévy-stable source functions. In this particular case, we find that the new method is more robust and allows the investigation of a wider parameter range than the previously utilized techniques. We present an easily applicable software package that is ready to use in experimental studies.

   ↳ nucl-thhep-exhep-phnucl-exEPJC(2023)·17 citations
6. 06*

   Majorana Demonstrator Data Release for AI/ML Applications

   I.J. Arnquist🇺🇸 · F.T. Avignone III🇺🇸 · A.S. Barabash🇷🇺 · C.J. Barton🇺🇸 · K.H. Bhimani🇺🇸 · E. Blalock🇺🇸 · B. Bos🇺🇸 · M. Busch🇺🇸 · M. Buuck🇺🇸 · T.S. Caldwell🇺🇸 · Y.-D. Chan🇺🇸 · C.D. Christofferson🇺🇸 and 48 other authors

   The enclosed data release consists of a subset of the calibration data from the Majorana Demonstrator experiment. Each Majorana event is accompanied by raw Germanium detector waveforms, pulse shape discrimination cuts, and calibrated final energies, all shared in an HDF5 file format along with relevant metadata. This release is specifically designed to support the training and testing of Artificial Intelligence (AI) and Machine Learning (ML) algorithms upon our data. This document is structured as follows. Section I provides an overview of the dataset's content and format; Section II outlines the location of this dataset and the method for accessing it; Section III presents the NPML Machine Learning Challenge associated with this dataset; Section IV contains a disclaimer from the Majorana collaboration regarding the use of this dataset; Appendix A contains technical details of this data release. Please direct questions about the material provided within this release to liaobo77@ucsd.edu (A. Li).

   ↳ cs.LGnucl-exphysics.data-anphysics.ins-det1 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.