abstract

The selection of \(\eta \) mesons with a high efficiency and a high purity can be important in the formation of statistically significant invariant mass spectra in the reconstruction of short-lived particles such as \(\eta ' \rightarrow \pi ^{+} \pi ^{-} \eta \). In this study, a cut-based standard method and a ranking method to reduce combinatorial background in the reconstruction of \(\eta \rightarrow \gamma \gamma \) decays in high multiplicity hadronic events are presented. By using recorded ALEPH data and fully simulated events, the performances of the methods are compared. Results show that the ranking method yields significant improvements in the purity of the selected \(\eta \) meson relative to the standard method.

abstract

Transverse momentum distributions and generalized parton distributions provide a comprehensive framework for the three-dimensional imaging of the nucleon and the nucleus experimentally using deeply virtual semi-exclusive and exclusive processes. The advent of combined high luminosity facilities and large acceptance detector capabilities enables experimental investigation of the partonic structure of hadrons with time-like virtual probes, in complement to the rich on-going space-like virtual probe program. The merits and benefits of the dilepton production channel for nuclear structure studies are discussed within the context of the International Workshop on Nucleon and Nuclear Structure through Dilepton Production taking place at the European Center for Theoretical Studies in Nuclear Physics and Related Areas (ECT\(^{\star }\)) of Trento. Particularly, the double deeply virtual Compton scattering, the time-like Compton scattering, the deeply virtual meson production, and the Drell–Yan processes are reviewed and a strategy for high impact experimental measurements is proposed.

abstract

We present a new method for constructing conformal Yano–Killing tensors in the five-dimensional Anti-de Sitter space-time. The found tensors are represented in two different coordinate systems. We also discuss, in terms of CYK tensors, global charges which are well-defined for asymptotically (five-dimensional) Anti-de Sitter space-time. Additionally, in Appendix A, we present our own derivation of conformal Killing one-forms in four-dimensional Anti-de Sitter space-time as an application of the Theorem 4.