Engineering topics

Deur, Alexandre

Publications and source records attributed to Deur, Alexandre.

3 records

DOE OSTI2024

QCD Running Coupling in the Nonperturbative and Near-Perturbative Regimes

We use analytic continuation to extend the gauge-gravity duality nonperturbative description of the strong force coupling into the transition, near-perturbative, regime where perturbative effects become important. By excluding the unphysical region in coupling space from the flow of singularities in the complex plane, we derive a specific relation between the scales relevant at large and short distances; this relation is uniquely fixed by requiring maximal analyticity. The unified effective coupling model gives an accurate description of the data in the nonperturbative and the near-perturbative regions.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2024

Nucleon Spin Sum Rules and Spin Polarizabilities at low $Q^2$

We report on recently published experimental studies on spin sum rules, namely the generalized Gerasimov-Drell-Hearn, Bjorken, Burkhardt-Cottingham, Schwinger, and generalized spin polarizability sum rules. The data were taken at Jefferson Lab in Halls A and B by experiments E97-110 and EG4, respectively. They covered the very low $Q^2$ domain, down to $Q^2$$\simeq$0.02 GeV$^2$, where Chiral Effective Field Theory ($\chi$EFT) predictions should be valid. While some of the obervables agree with the state-of-the-art $\chi$EFT predictions, others are in tensions, including the Longitudinal-Transverse interference polarizability $\delta_{\rm LT}^n(Q^2)$ for which $\chi$EFT prediction was expected to be robust. This suggests that $\chi$EFT does not yet consistently describes nucleon spin observables, even in the very low $Q^2$ domain covered by the experiments.

Deur, Alexandre↗

DOE OSTI2024

Nature's Strongest Force

The strongest force in the universe is called, aptly, the strong force. We never get to witness its fearsome power because it works only across subatomic distances, where it binds quarks together inside protons and neutrons and joins those nucleons into atomic nuclei. Of the four basic forces of nature, the strong force is by far the most potent—it’s 100 trillion trillion trillion times stronger than the force of gravity. Additionally, it’s also the most mysterious.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗