Tue·Jul 2, 2024Tuesday·July 2, 2024

1. 01*

   Imaging of single barium atoms in a second matrix site in solid xenon for barium tagging in a ${}^{136}$Xe double beta decay experiment

   M. Yvaine🇺🇸 · D. Fairbank🇺🇸 · J. Soderstrom🇺🇸 · C. Taylor🇺🇸 · J. Stanley🇺🇸 · T. Walton🇺🇸 · C. Chambers🇨🇦 · A. Iverson🇺🇸 · W. Fairbank🇺🇸 · S. Al Kharusi🇨🇦 · A. Amy🇫🇷 · E. Angelico🇺🇸 and 125 other authors

   Neutrinoless double beta decay is one of the most sensitive probes for new physics beyond the Standard Model of particle physics. One of the isotopes under investigation is ${}^{136}$Xe, which would double beta decay into ${}^{136}$Ba. Detecting the single ${}^{136}$Ba daughter provides a sort of ultimate tool in the discrimination against backgrounds. Previous work demonstrated the ability to perform single atom imaging of Ba atoms in a single-vacancy site of a solid xenon matrix. In this paper, the effort to identify signal from individual barium atoms is extended to Ba atoms in a hexa-vacancy site in the matrix and is achieved despite increased photobleaching in this site. Abrupt fluorescence turn-off of a single Ba atom is also observed. Significant recovery of fluorescence signal lost through photobleaching is demonstrated upon annealing of Ba deposits in the Xe ice. Following annealing, it is observed that Ba atoms in the hexa-vacancy site exhibit antibleaching while Ba atoms in the tetra-vacancy site exhibit bleaching. This may be evidence for a matrix site transfer upon laser excitation. Our findings offer a path of continued research toward tagging of Ba daughters in all significant sites in solid xenon.

   ↳ physics.atom-phhep-exnucl-exPRResearch(2024)·3 citations
2. 02*

   Mechanisms of mirror energy difference for states exhibiting Thomas-Ehrman shift: Gamow shell model case studies of ${}^{18}$Ne/${}^{18}$O and ${}^{19}$Na/${}^{19}$O

   J.G. Li · K. H. Li · N. Michel · H. H. Li · W. Zuo

   The mirror energy difference (MED) of the mirror state, especially for states bearing the Thomas-Erhman shift, serves as a sensitive probe of isospin symmetry breaking. We employ the Gamow shell model, which includes the inter-nucleon correlation and continuum coupling, to investigate the MED for $sd$-shell nuclei by taking the ${}^{18}$Ne/${}^{18}$O and ${}^{19}$Na/${}^{19}$O as examples. Our GSM provides good descriptions for the excitation energies and MEDs for the ${}^{18}$Ne/${}^{18}$O and ${}^{19}$Na/${}^{19}$O. Moreover, our calculations also reveal that the large MED of the mirror states is caused by the significant occupation of the weakly bound or unbound $s_{1/2}$ waves, giving the radial density distribution of the state in the proton-rich nucleus more extended than that of mirror states in deeply-bound neutron-rich nuclei. Furthermore, our GSM calculation shows that the contribution of Coulomb is different for the low-lying states in proton-rich nuclei, which significantly contributes to MEDs of mirror states. Moreover, the contributions of the nucleon-nucleon interaction are different for the mirror state, especially for the state of proton-rich nuclei bearing the Thomas-Erhman shift, which also contributes to the significant isospin symmetry breaking with large MED.

   ↳ nucl-thnucl-exNucl.Sci.Tech.(2026)·4 citations
3. 03*

   Applying Deep Learning Technique to Chiral Magnetic Wave Search

   Yuan-Sheng Zhao🇨🇳 · Xu-Guang Huang🇨🇳

   The chiral magnetic wave (CMW) is a collective mode in quark-gluon plasma originated from the chiral magnetic effect (CME) and chiral separation effect. Its detection in heavy-ion collisions is challenging due to significant background contamination. In Ref.[1], we have constructed a neural network which can accurately identify the CME-related signal from the final-state pion spectra. In this paper, we generalize such a neural network to the case of CMW search. We show that, after a updated training, the neural network can effectively recognize the CMW-related signal. Additionally, we assess the performance of the neural network compared to other known methods for CMW search.

   ↳ nucl-thnucl-exCPC(2024)·0 citations
4. 04*

   Measurement of the inclusive isolated-photon production cross section in pp collisions at $\sqrt{s}$ = 13 TeV

   ALICE Collaboration

   The production cross section of inclusive isolated photons has been measured by the ALICE experiment at the CERN LHC in pp collisions at centre-of-momentum energy of $\sqrt{s}=13$ TeV collected during the LHC Run 2 data-taking period. The measurement is performed by combining the measurements of the electromagnetic calorimeter EMCal and the central tracking detectors ITS and TPC, covering a pseudorapidity range of $|{\eta }^{\gamma }|<0.67$ and a transverse momentum range of $7<p_{\mathrm{T}}^{\gamma }<200$ GeV/$c$. The result extends to lower $p_{\mathrm{T}}^{\gamma }$ and $x_{\mathrm{T}}^{\gamma }=2p_{\mathrm{T}}^{\gamma }/\sqrt{s}$ ranges, the lowest $x_{\mathrm{T}}^{\gamma }$ of any isolated photon measurements to date, extending significantly those measured by the ATLAS and CMS experiments towards lower $p_{\mathrm{T}}^{\gamma }$ at the same collision energy with a small overlap between the measurements. The measurement is compared with next-to-leading order perturbative QCD calculations and the results from the ATLAS and CMS experiments as well as with measurements at other collision energies. The measurement and theory prediction are in agreement with each other within the experimental and theoretical uncertainties.

   ↳ hep-exnucl-exEPJC(2025)·9 citations
5. 05*

   Global analysis of fragmentation functions to charged hadrons with high-precision data from the LHC

   Jun Gao🇨🇳 · ChongYang Liu🇨🇳 · XiaoMin Shen🇨🇳 · Hongxi Xing🇨🇳 · Yuxiang Zhao🇨🇳

   Fragmentation functions (FFs) are essential non-perturbative QCD inputs for predicting hadron production cross sections in high energy scatterings. In this study, we present a joint determination of FFs for light charged hadrons through a global analysis at next-to-leading order (NLO) in QCD. Our analysis incorporates a wide range of precision measurements from the LHC, as well as data from electron-positron collisions and semi-inclusive deep inelastic scatterings. By including measurements of jet fragmentation at the LHC in our global analysis, we are able to impose strong constraints on the gluon FFs. A careful selection of hadron kinematics is applied to ensure the validity of factorization and perturbative calculations of QCD. In addition, we introduce several methodological advances in fitting, resulting in a flexible parametrization form and the inclusion of theoretical uncertainties from perturbative calculations. Our best-fit predictions show very good agreement with the global data, with ${\chi }^2/N_{pt}\sim 0.90$. We also generate a large number of Hessian error sets to estimate uncertainties and correlations of the extracted FFs. FFs to charged pions (kaons and protons) are well constrained for momentum fractions down to 0.01 (0.1). Total momentum of partons carried by light charged hadrons are determined precisely. Their values for $u$, $d$ quarks and gluon saturate at about 50\% for a lower cut of the momentum fraction of 0.01. Pulls from individual datasets and impact of various choices of the analysis are also studied in details. Additionally, we present an update of the FMNLO program used for calculating hadron production cross sections. Our FFs, including the error sets (denoted as NPC23), are publicly available in the form of LHAPDF6 grids.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2024)·49 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.