Thu·Mar 24, 2022Thursday·March 24, 2022

1. 01*

   Deuteron analyzing powers $A_y$, $A_{yy}$ and $A_{xx}$ in dp-elastic scattering at large transverse momenta

   V.P.Ladygin🇷🇺 · A.V.Averyanov · E.V.Chernykh · D.Enache · Yu.V.Gurchin · A.Yu.Isupov · M.Janek · J.-T.Karachuk · A.N.Khrenov · D.O.Krivenkov · P.K.Kurilkin🇷🇺 · N.B.Ladygina and 9 other authors

   The results on the the vector $A_y$, $A_{yy}$ and $A_{xx}$ analyzing powers in deuteron-proton elastic scattering at large scattering angles are presented. These data were obtained at internal target at JINR Nuclotron in the energy range 400-1800 MeV using polarized deuteron beam from new polarized ion source. New data on the deuteron analyzing powers in the wide energy range demonstrate the sensitivity to the short-range spin structure of the isoscalar nucleon-nucleon correlations.

   nucl-exJPS Conf.Proc.(2022)·1 citation
2. 02*

   Low-$p_T$ direct-photon production in Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=39$ and 62.4 GeV

   N.J. Abdulameer · U. Acharya · A. Adare · C. Aidala · N.N. Ajitanand · Y. Akiba · R. Akimoto · H. Al-Ta'ani · J. Alexander · M. Alfred · A. Angerami · K. Aoki and 423 other authors

   The measurement of direct photons from Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=39$ and 62.4 GeV in the transverse-momentum range $0.4<p_T<3$ Gev/$c$ is presented by the PHENIX collaboration at the Relativistic Heavy Ion Collider. A significant direct-photon yield is observed in both collision systems. A universal scaling is observed when the direct-photon $p_T$ spectra for different center-of-mass energies and for different centrality selections at $\sqrt{s_{{}_{NN}}}=62.4$ GeV is scaled with $(d{N}_{\mathrm{ch}}/d\eta {)}^{\alpha }$ for $\alpha =1.21\pm 0.04$. This scaling also holds true for direct-photon spectra from Au$+$Au collisions at $\sqrt{s_{{}_{NN}}}=200$ GeV measured earlier by PHENIX, as well as the spectra from Pb$+$Pb at $\sqrt{s_{{}_{NN}}}=2760$ GeV published by ALICE. The scaling power $\alpha$ seems to be independent of $p_T$, center of mass energy, and collision centrality. The spectra from different collision energies have a similar shape up to $p_T$ of 2 GeV/$c$. The spectra have a local inverse slope $T_{\mathrm{eff}}$ increasing with $p_T$ of $0.174\pm 0.018$ GeV/$c$ in the range $0.4<p_T<1.3$ GeV/$c$ and increasing to $0.289\pm 0.024$ GeV/$c$ for $0.9<p_T<2.1$ GeV/$c$. The observed similarity of low-$p_T$ direct-photon production from $\sqrt{s_{{}_{NN}}}=39$ to 2760 GeV suggests a common source of direct photons for the different collision energies and event centrality selections, and suggests a comparable space-time evolution of direct-photon emission.

   nucl-exPRC(2023)·32 citations
3. 03*

   High precision measurement of the half-life of the 391.6 keV metastable level in 239Pu

   A. Barresi🇮🇹 · D. Chiesa🇮🇹 · M. Nastasi🇮🇹 · E. Previtali🇮🇹 · M. Sisti🇮🇹

   Materials selection for rare event physics requires high performance detectors and customized analyses. In this context a novel $\beta$-$\gamma$ detection system, comprised of a liquid scintillator in coincidence with a HPGe, was developed with the main purpose of studying ultra trace contamination of uranium, thorium and potassium in liquid samples. In the search for ${}^{238}\text{U}$ contaminations through neutron activation analysis, since the activation product ${}^{239}\text{Np}$ decays to a relatively long-lived isomeric state of ${}^{239}\text{Pu}$, it is possible to perform a time selection of these events obtaining a strong background suppression. Investigating the time distribution of the coincidences between the ${\beta }^{-}$ decay of ${}^{239}\text{Np}$ and the delayed events following the de-excitation of the ${}^{239}\text{Pu}$ isomeric level at 391.6 keV, a precision measurement of the half-life of this level was conducted. The half-life of the 391.6 keV ${}^{239}\text{Pu}$ level resulted $190.2\pm 0.2$ ns, thus increasing the precision by about a factor of 20 over previous measurements.

   nucl-exPRC(2022)·1 citation
4. 04*

   Composition of low-lying $\mathbf{J}={\frac{3}{2}}^{\pm }\mathbf{\Delta }$-baryons

   Langtian Liu🇨🇳 · Chen Chen🇨🇳 · Ya Lu🇨🇳 · Craig D. Roberts🇨🇳 · Jorge Segovia🇪🇸

   A Poincaré-covariant quark+diquark Faddeev equation is used to develop insights into the structure of the four lightest $(I,J^P=\frac{3}{2},{\frac{3}{2}}^{\pm })$ baryon multiplets. Whilst these systems can contain isovector-axialvector and isovector-vector diquarks, one may neglect the latter and still arrive at a reliable description. The $(\frac{3}{2},{\frac{3}{2}}^{+})$ states are the simpler systems, with features that bear some resemblance to quark model pictures, \emph{e.g}., their most prominent rest-frame orbital angular momentum component is $\mathsf{S}$-wave and the $\Delta (1600){\frac{3}{2}}^{+}$ may reasonably be viewed as a radial excitation of the $\Delta (1232){\frac{3}{2}}^{+}$. The $(\frac{3}{2},{\frac{3}{2}}^{-})$ states are more complex: the $\Delta (1940){\frac{3}{2}}^{-}$ expresses little of the character of a radial excitation of the $\Delta (1700){\frac{3}{2}}^{-}$; and whilst the rest-frame wave function of the latter is predominantly $\mathsf{P}$-wave, the leading piece in the $\Delta (1940){\frac{3}{2}}^{-}$ wave function is $\mathsf{S}$-wave, in conflict with quark model expectations. Experiments that can test these predictions, such as large momentum transfer resonance electroexcitation, may shed light on the nature of emergent hadron mass.

   ↳ hep-phhep-exhep-latnucl-ex+1PRD(2022)·33 citations
5. 05*

   Neutrinoless Double-Beta Decay: A Roadmap for Matching Theory to Experiment

   Vincenzo Cirigliano🇺🇸 · Zohreh Davoudi🇺🇸 · Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Jonathan Engel🇺🇸 · Xu Feng🇨🇳 · Julia Gehrlein🇺🇸 · Michael L. Graesser🇺🇸 · Lukáš Gráf🇺🇸 · Heiko Hergert🇺🇸 · Luchang Jin🇺🇸 · Emanuele Mereghetti🇺🇸 and 7 other authors

   The observation of neutrino oscillations and hence non-zero neutrino masses provided a milestone in the search for physics beyond the Standard Model. But even though we now know that neutrinos are massive, the nature of neutrino masses, i.e., whether they are Dirac or Majorana, remains an open question. A smoking-gun signature of Majorana neutrinos is the observation of neutrinoless double-beta decay, a process that violates the lepton-number conservation of the Standard Model. This white paper focuses on the theoretical aspects of the neutrinoless double-beta decay program and lays out a roadmap for future developments. The roadmap is a multi-scale path starting from high-energy models of neutrinoless double-beta decay all the way to the low-energy nuclear many-body problem that needs to be solved to supplement measurements of the decay rate. The path goes through a systematic effective-field-theory description of the underlying processes at various scales and needs to be supplemented by lattice quantum chromodynamics input. The white paper also discusses the interplay between neutrinoless double-beta decay, experiments at the Large Hadron Collider and results from astrophysics and cosmology in probing simplified models of lepton-number violation at the TeV scale, and the generation of the matter-antimatter asymmetry via leptogenesis. This white paper is prepared for the topical groups TF11 (Theory of Neutrino Physics), TF05 (Lattice Gauge Theory), RF04 (Baryon and Lepton Number Violating Processes), NF03 (Beyond the Standard Model) and NF05 (Neutrino Properties) within the Theory Frontier, Rare Processes and Precision Frontier, and Neutrino Physics Frontier of the U.S. Community Study on the Future of Particle Physics (Snowmass 2021).

   ↳ hep-phhep-exhep-latnucl-ex+196 citations
6. 06*

   Selected topics in diffraction with protons and nuclei: past, present, and future

   L. Frankfurt (Tel Aviv U. and Penn State U.)🇮🇱 · V. Guzey (St. Petersburg, INP)🇷🇺 · A. Stasto (Penn State U.)🇺🇸 · M. Strikman (Penn State U.)🇺🇸

   We review a broad range of phenomena in diffraction in the context of hadron-hadron, hadron-nucleus collisions and deep inelastic lepton-proton/nucleus scattering focusing on the interplay between the perturbative QCD and non-perturbative models. We discuss inclusive diffraction in DIS, phenomenology of dipole models, resummation and parton saturation at low $x$, hard diffractive production of vector mesons, inelastic diffraction in hadron-hadron scattering, formalism of color fluctuations, inclusive coherent and incoherent diffraction as well as soft and hard diffraction phenomena in hadron-hadron/nucleus and photon-nucleus collisions. For each topic we review key results from the past and present experiments including HERA and the LHC. Finally, we identify the remaining open questions, which could be addressed in the continuing experiments, in particular in photon-induced reactions at the LHC and the future Electron-Ion Collider (EIC) in the US, Large Hadron electron Collider (LHeC) and Future Circular Collider (FCC) at CERN.

   ↳ hep-phhep-exnucl-exRept.Prog.Phys.(2022)·40 citations
7. 07*

   Spin Physics Detector at NICA

   V.P.Ladygin (on behalf of the SPD Collaboration)🇷🇺

   The Spin Physics Detector is one of two large setups at the NICA collider under construction at JINR (Dubna). The ultimate goal of the studies at SPD is the measurement of different spin observables in polarized proton-proton and deuteron-deuteron collisions sensitive to the polarized gluon structure of the nucleon at the luminosity up to 10${}^{32}$ $c{m}^{-2}\cdot s^{-1}$ and $\sqrt{s}$ up to 27 GeV. SPD will consist of the superconducting magnetic system, silicon tracker, straw mini-drift tubes tracker, time-of-flight system, electromagnetic "shashlyk"- type calorimeter, muon (range) and local-polarimetry systems. The high performance free-streaming DAQ system will be able to operate at the collision rate up to 4 MHz.

   ↳ hep-exnucl-exJPS Conf.Proc.(2022)·2 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.