Wed·Feb 23, 2022Wednesday·February 23, 2022

1. 01*

   Results on spin sum rules and polarizabilities at low $Q^2$

   Alexandre Deur🇺🇸

   We report on recently published experimental results on spin sum rules, and particularly on the generalized spin polarizabilities ${\gamma }_0(Q^2)$ (for both the proton and neutron) and ${\delta }_{\mathrm{LT}}(Q^2)$ (for the neutron). The data were taken at Jefferson Lab in Hall A by experiment E97110 (neutron) and in Hall B by experiments E03006 and E05111 (proton and deuteron, respectively). The experiments covered the very low $Q^2$ domain, down to $Q^2\simeq 0.02$ GeV${}^2$. This is well into the domain where Chiral Effective Field Theory ($\chi$EFT) predictions should be valid. Some measured observables agree with the state-of-the-art $\chi$EFT predictions but others are in tension, including ${\delta }_{\mathrm{LT}}^n(Q^2)$ which $\chi$EFT prediction was expected to be robust. This suggests that $\chi$EFT does not yet consistently describe nucleon spin observables, even at the very low $Q^2$ covered by the experiments.

   nucl-exPoS(2024)·2 citations
2. 02*

   Implications of the first evidence for coherent elastic scattering of reactor neutrinos

   Jiajun Liao🇨🇳 · Hongkai Liu🇮🇱 · Danny Marfatia🇺🇸

   The recent evidence for coherent elastic neutrino-nucleus scattering (CE$\nu$NS) in the NCC-1701 germanium detector using antineutrinos from the Dresden-II nuclear reactor is in good agreement with standard model expectations. However, we show that a $2\sigma$ improvement in the fit to the data can be achieved if the quenching factor is described by a modified Lindhard model. We also place constraints on the parameter space of a light vector or scalar mediator that couples to neutrinos and quarks, and on a neutrino magnetic moment. We demonstrate that the constraints are quite sensitive to the quenching factor at low recoil energies by comparing constraints for the standard Lindhard model with those by marginalizing over the two parameters of the modified Lindhard model.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2022)·30 citations
3. 03*

   A novel active veto prototype detector with an inner target for improved rare event searches

   M. Chaudhuri🇮🇳 · A. Jastram🇺🇸 · G. Agnolet🇺🇸 · S. Banik🇮🇳 · H. Chen🇺🇸 · V. Iyer🇮🇳 · V. K. S. Kashyap🇮🇳 · A. Kubik🇨🇦 · M. Lee🇺🇸 · R. Mahapatra🇺🇸 · S. Maludze🇺🇸 · N. Mirabolfathi🇺🇸 and 4 other authors

   We report the fabrication and performance of an annular, cryogenic, phonon-mediated veto detector that can host an inner target detector, allowing substantial reduction in radiogenic backgrounds for rare event search experiments. A germanium veto detector of mass $\sim$500 g with an outer diameter of 76 mm and an inner diameter of 28 mm was produced. A 25 mm diameter germanium inner target detector of mass $\sim$10 g was mounted inside the veto detector. The detector was designed using inputs from a GEANT4 based simulation, where it was modeled to be sandwiched between two germanium detectors. The simulation showed that the background rates (dominantly gamma interactions) could be reduced by $>$ 90$\%$, and that such an arrangement is sufficient for aggressive background reduction needed for neutrino and dark matter search experiments. During testing at the experimental site the veto detector prototype achieved a baseline resolution of 1.24 $\pm$ 0.02 keV while hosting a functional inner target detector. The baseline resolution of the inner target detector was 147 $\pm$ 2 eV. The detectors were operated at mK temperatures. The experimental results of an identical detector arrangement are in excellent agreement with the simulation.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2022)·1 citation
4. 04*

   Twist-three cross-sections in deeply virtual Compton scattering

   Yuxun Guo🇺🇸 · Xiangdong Ji🇺🇸 · Brandon Kriesten🇺🇸 · Kyle Shiells🇺🇸

   We study the deeply virtual Compton scattering process with both twist-two and twist-three Compton form factors and present our cross-sections formulas with all polarization configurations. While the twist-three contributions are generally assumed to be negligible in the literature due to the kinematical suppression, we compare them with the twist-two ones at typical JLab 6 GeV and 12 GeV kinematics as well as EIC kinematics and show their kinematical suppression explicitly, justifying the leading-twist approximation made in the literature. In addition, we also estimate the twist-three Compton form factors using Wandzura-Wilczek relations and inputs of twist-two generalized parton distributions based on a reggeized spectator model. With those estimated Compton form factors, we analyze the kinematical behavior of twist-two and twist-three cross-sections in a wide range of kinematics, and discuss the optimal regions for separating the leading-twist effects from the higher-twist ones.

   ↳ hep-phnucl-exnucl-thJHEP(2022)·17 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.