Thu·Sep 10, 2020Thursday·September 10, 2020

1. 01*

   Charge radii of the nucleon from its flavor dependent Dirac form factors

   H.Atac🇺🇸 · M. Constantinou🇺🇸 · Z.-E. Meziani🇺🇸 · M. Paolone🇺🇸 · N. Sparveris🇺🇸

   We have determined the proton and the neutron charge radii from a global analysis of the proton and the neutron elastic form factors, after first performing a flavor decomposition of these form factors under charge symmetry in the light cone frame formulation. We then extracted the transverse mean-square radii of the flavor dependent quark distributions. In turn, these are related in a model-independent way to the proton and neutron charge radii but allow us to take into account motion effects of the recoiling nucleon for data at finite but high momentum transfer. In the proton case we find $⟨r_p⟩=0.852\pm 0.002_{(stat.)}\pm 0.009_{(syst.)}(\mathrm{fm})$, consistent with the proton charge radius obtained from muonic hydrogen spectroscopy \cite{pohl:2010,antog2013}. The current method improves on the precision of the $⟨r_p⟩$ extraction based on the form factor measurements. Furthermore, we find no discrepancy in the $⟨r_p⟩$ determination among the different electron scattering measurements, all of which, utilizing the current method of extraction, result in a value that is consistent with the smallest $⟨r_p⟩$ extraction from the electron scattering measurements \cite{Xiong:2019umf}. Concerning the neutron case, past results relied solely on the neutron-electron scattering length measurements, which suffer from an underestimation of underlying systematic uncertainties inherent to the extraction technique. Utilizing the present method we have performed the first extraction of the neutron charge radius based on nucleon form factor data, and we find $⟨r_n^2⟩=-0.122\pm 0.004_{(stat.)}\pm 0.010_{(syst.)}({\mathrm{fm}}^2)$.

   nucl-exEPJA(2021)·29 citations
2. 02*

   Empirical Consequences of Emergent Mass

   Craig D. Roberts🇨🇳

   The Lagrangian that defines quantum chromodynamics (QCD), the strong interaction piece of the Standard Model, appears very simple. Nevertheless, it is responsible for an astonishing array of high-level phenomena with enormous apparent complexity, e.g., the existence, number and structure of atomic nuclei. The source of all these things can be traced to emergent mass, which might itself be QCD's self-stabilising mechanism. A background to this perspective is provided, presenting, inter alia, a discussion of the gluon mass and QCD's process-independent effective charge and highlighting an array of observable expressions of emergent mass, ranging from its manifestations in pion parton distributions to those in nucleon electromagnetic form factors.

   ↳ hep-phhep-exhep-latnucl-ex+1Symmetry(2020)·95 citations
3. 03*

   Neutral-current background induced by atmospheric neutrinos at large liquid-scintillator detectors: II. Methodology for in situ measurements

   Jie Cheng🇨🇳 · Yu-Feng Li🇨🇳 · Hao-Qi Lu🇨🇳 · Liang-Jian Wen🇨🇳

   Future large liquid-scintillator (LS) detectors are competitive with and complementary to the water-Cherenkov detectors on the searches for diffuse supernova neutrino background and nucleon decay. In a companion paper, we have performed a systematic calculation of the neutral-current (NC) background induced by atmospheric neutrino interactions on ${}^{12}\mathrm{C}$ nuclei in LS detectors, which are expected to be crucially important for the experimental searches for the diffuse supernova neutrino background and nucleon decay. In this paper, we perform a systematic study on the measurement of the NC background and evaluate the associated uncertainties. We first exploit the characteristics of the NC background, in particular, the multiplicities of neutrons and pions, and the possible association with unstable residual nuclei. It turns out that the neutron multiplicity distribution is very powerful to discriminate among different models. Then, we develop a maximum-likelihood method to allow an {\it in situ} measurement of the NC interactions with a triple-coincidence signature. Finally, a data-driven approach is proposed to evaluate the uncertainty of the NC background in the search for the diffuse supernova neutrino background. We conclude that future large LS experiments like JUNO (Jiangmen Underground Neutrino Observatory) will be able to make a unique contribution to the worldwide data set to improve the prediction of atmospheric neutrino NC interactions on ${}^{12}$C.

   ↳ hep-exastro-ph.HEhep-phnucl-ex+1PRD(2021)·19 citations
4. 04*

   Triaxial projected shell model study of $\gamma$-bands in atomic nuclei

   S. Jehangir · G.H. Bhat🇮🇳 · J.A. Sheikh · S. Frauendorf🇺🇸 · W. Li🇨🇳 · R. Palit🇮🇳

   A systematic study of $\gamma$-bands observed in atomic nuclei is performed using the triaxial projected shell model (TPSM) approach. The staggering phase between the even and odd spin members of the $\gamma$-band for most the nuclei investigated in the present work is found to have even-I-below-odd-I, which in the framework of the collective model is considered as a signature of $\gamma$-softness. It is observed that out of twenty-three systems studied, only four nuclei, namely, ${}^{76}$Ge, ${}^{112}$Ru, ${}^{170}$Er and ${}^{232}$Th depict staggering phase with odd-I-below-even-I, which is regarded as an indication of the static $\gamma$-deformation in the collective model picture. The inclusion of the quasiparticle excitations in the framework of configuration mixing is shown to reverse the staggering phase from odd-I-down to the even-I-down for all the studied nuclei, except for the aforementioned four nuclei. Furthermore, by fitting a collective Bohr Hamiltonian to the TPSM energies, the differences between the two models are delineated through a comparison of the transition probabilities.

   ↳ nucl-thnucl-exEPJA(2021)·41 citations
5. 05*

   Snowmass 2021 LoI: Neutrino-induced Shallow- and Deep-Inelastic Scattering

   L. Alvarez-Ruso🇪🇸 · A. M. Ankowski🇺🇸 · M. Sajjad Athar🇮🇳 · C. Bronner🇯🇵 · L. Cremonesi🇬🇧 · K. Duffy🇺🇸 · S. Dytman🇺🇸 · A. Friedland🇺🇸 · A. P. Furmanski🇺🇸 · K. Gallmeister🇩🇪 · S. Gardiner🇺🇸 · W. T. Giele🇺🇸 and 21 other authors

   In neutrino interactions with nucleons and nuclei, Shallow Inelastic Scattering (SIS) refers to processes, dominated by non-resonant contributions, in the kinematic region where $Q^2$ is small and the invariant mass of the hadronic system, $W$, is above the pion production threshold. The extremely rich science of this complex region, poorly understood both theoretically and experimentally, encompasses the transition from interactions described in terms of hadronic degrees of freedom to interactions with quarks and gluons described by perturbative QCD. Since a large fraction of events in NOvA and DUNE, and in atmospheric neutrino measurements such as IceCube-Upgrade, KM3NeT, Super- and Hyper-Kamiokande, are from this SIS region, there is a definite need to improve our knowledge of this physics. This LoI summarizes the current understandings of the SIS physics and a series of proposals for the path to forward.

   ↳ hep-exnucl-ex7 citations
6. 06*

   Neutron Polarimetry Using a Polarized 3He Cell for the aCORN Experiment

   B. C. Schafer · W. A. Byron🇺🇸 · W. C. Chen · B. Collett🇺🇸 · M. S. Dewey🇺🇸 · T. R. Gentile🇺🇸 · Md. T. Hassan🇺🇸 · G. L. Jones · A. Komives🇺🇸 · F. E. Wietfeldt🇺🇸

   The neutron polarization of the NG-C beamline at the NIST Center for Neutron Research was measured as part of the aCORN neutron beta decay experiment. Neutron transmission through a polarized 3He spin filter cell was recorded while adiabatic fast passage (AFP) nuclear magnetic resonance (NMR) reversed the polarization direction of the 3He in an eight-step sequence to account for drifts. The dependence of the neutron transmission on the spin filter direction was used to calculate the neutron polarization. The time dependent transmission was fit to a model which included the neutron spectrum, and 3He polarization losses from spin relaxation and AFP-NMR. The polarization of the NG-C beamline was found to be $\mid P_{\mathrm{n}}\mid \le 4\times 10^{-4}$ with 90 % confidence.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2021)·3 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.