Fri·Apr 17, 2020Friday·April 17, 2020

1. 01*

   ${}^{12}$C(e,e'pN) Measurements of Short Range Correlations in the Tensor-to-Scalar Interaction Transition Region

   I. Korover · J. R. Pybus · A. Schmidt · F. Hauenstein · M. Duer · O. Hen · E. Piasetzky · L.B. Weinstein · D.W. Higinbotham · the CLAS Collaboration

   High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the ${}^{12}$C$(e,e^{\prime }p)$ and ${}^{12}$C$(e,e^{\prime }pN)$ reactions (where $N$ is either $n$ or $p$), at high-$Q^2$ and $x_B>1.1$. The data span a missing-momentum range of 300--1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon ($NN$) interaction models. This agreement suggests that the measured high missing-momentum protons up to $1000$ MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured ${}^{12}$C$(e,e^{\prime }pN)$ / ${}^{12}$C$(e,e^{\prime }p)$ and ${}^{12}$C$(e,e^{\prime }pp)$ / ${}^{12}$C$(e,e^{\prime }pn)$ cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor $NN$ interaction at $\sim 400$ MeV/c to an isospin-independent scalar interaction at high-momentum around $\sim 800$ MeV/c as predicted by theoretical calculation.

   nucl-exhep-phnucl-thPLB(2021)·48 citations
2. 02*

   Scaling of high-energy elastic scattering and the observation of Odderon

   T. Csörgő🇭🇺 · T. Novák🇭🇺 · R. Pasechnik🇸🇪 · A. Ster🇭🇺 · I. Szanyi🇭🇺

   We provide a statistically significant observation of the elusive Odderon exchange, based on novel and model-independent analysis of the scaling properties of the differential cross sections of elastic $pp$ and $p\bar{p}$ scattering in the TeV energy range. We report the statistical significance of the observed Odderon signal at the level of 6.26$\sigma$.

   ↳ hep-phhep-exnucl-exGribov-90 Memorial Volume, pp. 69-80 (202…·4 citations
3. 03*

   Quantifying uncertainties and correlations in the nuclear-matter equation of state

   C. Drischler🇺🇸 · J. A. Melendez🇺🇸 · R. J. Furnstahl🇺🇸 · D. R. Phillips🇺🇸

   We perform statistically rigorous uncertainty quantification (UQ) for chiral effective field theory ($\chi$EFT) applied to infinite nuclear matter up to twice nuclear saturation density. The equation of state (EOS) is based on high-order many-body perturbation theory calculations with nucleon-nucleon and three-nucleon interactions up to fourth order in the $\chi$EFT expansion. From these calculations our newly developed Bayesian machine-learning approach extracts the size and smoothness properties of the correlated EFT truncation error. We then propose a novel extension that uses multitask machine learning to reveal correlations between the EOS at different proton fractions. The inferred in-medium $\chi$EFT breakdown scale in pure neutron matter and symmetric nuclear matter is consistent with that from free-space nucleon-nucleon scattering. These significant advances allow us to provide posterior distributions for the nuclear saturation point and propagate theoretical uncertainties to derived quantities: the pressure and incompressibility of symmetric nuclear matter, the nuclear symmetry energy, and its derivative. Our results, which are validated by statistical diagnostics, demonstrate that an understanding of truncation-error correlations between different densities and different observables is crucial for reliable UQ. The methods developed here are publicly available as annotated Jupyter notebooks.

   ↳ nucl-thastro-ph.HEhep-phnucl-exPRC(2020)·170 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.