Mon·Feb 12, 2024Monday·February 12, 2024

1. 01*

   Penning-trap measurement of the $Q$-value of the electron capture in ${}^{163}\mathrm{Ho}$ for the determination of the electron neutrino mass

   Christoph Schweiger🇩🇪 · Martin Braß🇩🇪 · Vincent Debierre🇩🇪 · Menno Door🇩🇪 · Holger Dorrer🇩🇪 · Christoph E. Düllmann🇩🇪 · Christian Enss🇩🇪 · Pavel Filianin🇩🇪 · Loredana Gastaldo🇩🇪 · Zoltán Harman🇩🇪 · Maurits W. Haverkort🇩🇪 · Jost Herkenhoff🇩🇪 and 10 other authors

   The investigation of the absolute scale of the effective neutrino mass remains challenging due to the exclusively weak interaction of neutrinos with all known particles in the standard model of particle physics. Currently, the most precise and least model-dependent upper limit on the electron antineutrino mass is set by the KATRIN experiment from the analysis of the tritium \b{eta}-decay. Another promising approach is the electron capture in ${}^{163}\mathrm{Ho}$, which is under investigation using microcalorimetry within the ECHo and HOLMES collab orations. An independently measured Q-value of this process is vital for the assessment of systematic uncertainties in the neutrino mass determination. Here, we report a direct, independent determination of this $Q$-value by measuring the free-space cyclotron frequency ratio of highly charged ions of ${}^{163}\mathrm{Ho}$ and ${}^{163}\mathrm{Dy}$ in the Penning trap experiment \textsc{Pentatrap}. Combining this ratio with atomic physics calculations of the electronic binding energies yields a $Q$-value of $2863.2(0.6)\mathrm{eV}/c^2$ - a more than 50-fold improvement over the state-of-the-art. This will enable the determination of the electron neutrino mass on a sub-eV level from the analysis of the electron capture in ${}^{163}\mathrm{Ho}$.

   nucl-exNat.Phys.(2024)·15 citations
2. 02*

   Contact interaction study of proton parton distributions

   Yang Yu🇨🇳 · Peng Cheng🇨🇳 · Hui-Yu Xing🇨🇳 · Fei Gao🇨🇳 · Craig D. Roberts🇨🇳

   Using a symmetry-preserving formulation of a vector$\times$vector contact interaction (SCI) and treating the proton as a quark + interacting-diquark bound state, whose structure is obtained by solving a Poincaré-covariant Faddeev equation, we provide a comprehensive, coherent set of predictions for unpolarised and polarised proton parton distribution functions (DFs): valence, glue, and four-flavour separated sea. The results enable many themes to be addressed, including: the asymmetry of antimatter in the proton; the neutron:proton structure function ratio; helicity retention in hard scattering processes; the charm quark momentum fraction; the sign and size of the polarised gluon DF; and the origin of the proton spin. In all cases where sound analyses of data are available, SCI predictions are semiquantitatively in agreement with the results. Those mismatches which exist are typically attributable to the momentum-independence of the underlying interaction. Judiciously interpreted, the SCI delivers a sound and insightful explanation of proton structure as expressed in DFs.

   ↳ hep-phhep-exhep-latnucl-ex+1EPJC(2024)·24 citations
3. 03*

   The $ppp$ correlation function with a screened Coulomb potential

   A. Kievsky🇮🇹 · E. Garrido🇪🇸 · M. Viviani🇮🇹 · M. Gattobigio🇫🇷

   The correlation function is a useful tool to study the interaction between hadrons. The theoretical description of this observable requires the knowledge of the scattering wave function, whose asymptotic part is distorted when two or more particles are charged. For a system of three (or more) particles, with more than two particles asymptotically free and at least two of them charged, the asymptotic part of the wave function is not known in a closed form. In the present study we introduce a screened Coulomb potential and analyze the impact of the screening radius on the correlation function. As we will show, when a sufficiently large screening radius is used, the correlation function results almost unchanged if compared to the case in which the unscreened Coulomb potential is used. This fact allows the use of free asymptotic matching conditions in the solution of the scattering equation simplifying noticeably the calculation of the correlation function. As an illustration we discuss the $pp$ and $ppp$ correlation functions.

   ↳ nucl-thnucl-exFew Body Syst.(2024)·5 citations
4. 04*

   Elliptic flow of deuterons in ultrarelativistic heavy-ion collisions

   Radka Vozabova🇨🇿 · Boris Tomasik🇸🇰

   We calculate the elliptic flow of deuterons in Pb+Pb collisions at 2.76 TeV per colliding nucleon-nucleon pair and show that it can be used to discriminate between direct statistical production and coalescence. The emission from the fireball is parametrized and tuned to reproduce transverse momentum spectra and the elliptic flow of protons and pions. Coalescence leads to higher deuteron elliptic flow than statistical production and agrees better with experimental data. We attribute this observation to the varying size of the nucleon-producing region for the emission in different azimuthal angles.

   ↳ nucl-thnucl-exPRC(2024)·7 citations
5. 05*

   Deuterated Polystyrene -- Synthesis and uses for ultracold neutron bottles and the neutron EDM experiment

   Steve K. Lamoreaux🇺🇸

   The synthesis and application of deuterated polystyrene (dps) films is discussed. Ultracold neutron storage properties and the Fermi potential of dps films is measured with the result that Tstore=700 +/- 200 sec for dps in the bottle used and the Fermi potential is about 165neV. The behavior under application of high electric fields in vacuum is measured; the films are sufficiently stable to use in a neutron EDM bottle. Also, the relaxation rate of nuclear spin polarized 199Hg on dps films is measured giving a wall lifetime of 20 sec/cm mean free path, which should make the development of an Hg volume magnetometer possible.

   ↳ hep-exnucl-ex2 citations
6. 06*

   Multiplicity Based Background Subtraction for Jets in Heavy Ion Collisions

   Tanner Mengel🇺🇸 · Patrick Steffanic🇺🇸 · Charles Hughes🇺🇸 · Antonio Carlos Oliveira Da Silva🇺🇸 · Christine Nattrass🇺🇸

   Jet measurements in heavy ion collisions at low jet momentum can provide constraints on the properties of the quark gluon plasma but are overwhelmed by a significant, fluctuating background. We build upon our previous work which demonstrated the ability of the jet multiplicity method to extend jet measurements into the domain of low jet momentum [1, Mengel:2023]. We extend this method to a wide range of jet resolution parameters. We investigate the over-complexity of non-interpretable machine learning used to tackle the problem of jet background subtraction through network optimization. Finally, we show that the resulting shallow neural network is able to learn the underlying relationship between jet multiplicity and background fluctuations, with a lesser complexity, reinforcing the utility of interpretable methods.

   ↳ hep-exnucl-ex6 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.