Joan Soto

Heavy quarkonium physics

This report is the result of the collaboration and research effort of the Quarkonium Working Group over the last three years. It provides a comprehensive overview of the state of the art in heavy-quarkonium theory and experiment, covering quarkonium spectroscopy, decay, and production, the determination of QCD parameters from quarkonium observables, quarkonia in media, and the effects on quarkonia of physics beyond the Standard Model. An introduction to common theoretical and experimental tools is included. Future opportunities for research in quarkonium physics are also discussed.

Physics at BES-III

We give a detailed review of the construction of gauge invariant Lagrangians for free and interacting higher spin fields using the BRST approach developed over the past few years.This physics book provides detailed discussions on important topics in

Effective field theory for ultrasoft momenta in NRQCD and NRQED

\tau

Infrared behavior of the static potential in perturbative QCD

-charm physics that will be explored during the next few years at \bes3 . Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and \DzDzb-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.

Potential NRQED: The positronium case

Abstract We propose an effective field theory for heavy quark-antiquark bound states once the soft gluons have been integrated out. We also new results for the matching between QCD (QED) and NRQCD (NRQED).

Heavy quarkonium in a weakly-coupled quark-gluon plasma below the melting temperature

The definition of the quark-antiquark static potential is given within an effective field theory framework. The leading infrared divergences of the static singlet potential in perturbation theory are explicitly calculated.

Nonrelativistic bound states at finite temperature : The hydrogen atom

We discuss in detail potential NRQED (pNRQED), a previously proposed effective field theory for ultrasoft photons. The pNRQED lagrangian for the equal mass case is presented and it is shown that it correctly reproduces the positronium spectrum at order

The Lamb Shift in Dimensional Regularisation

m\alpha^5

Determination of

. The pNRQED lagrangian for the unequal mass case is also presented at the same order. Dimensional regularization is used throughout.

\alpha_s

We calculate the heavy quarkonium energy levels and decay widths in a quark-gluon plasma, whose temperature T and screening mass mDsatisfy the hierarchy mαs ≫ T ≫ mαs2 ≫mD (m being the heavy-quark mass), at order mαs5 . We first sequentially integrate out the scales m, mαs and T, and, next, we carry out the calculations in the resulting effective theory using techniques of integration by regions. A collinear region is identified, which contributes at this order. We also discuss the implications of our results concerning heavy quarkonium suppression in heavy ion collisions.