511 research outputs found
The Role of the QCD Vacuum in the Heavy-Quark Bound State Dynamics
The effective field theory approach allows a rigorous disentangling of high
and low energy effects in the heavy quarkonium dynamics. Focusing in particular
on the spectrum, we describe the nature of the non-perturbative effects and
discuss our present knowledge of them.Comment: Invited talk presented at the Fifth Workshop on Quantum
Chromodynamics, Villefranche-sur-Mer, France, 3-7 January 2000; 9 pages,
sprocl.st
The three-quark static potential in perturbation theory
We study the three-quark static potential in perturbation theory in QCD. A
complete next-to-leading order calculation is performed in the singlet, octets
and decuplet channels and the potential exponentiation is demonstrated. The
mixing of the octet representations is calculated. At next-to-next-to-leading
order, the subset of diagrams producing three-body forces is identified in
Coulomb gauge and its contribution to the potential calculated. Combining it
with the contribution of the two-body forces, which may be extracted from the
quark-antiquark static potential, we obtain the complete
next-to-next-to-leading order three-quark static potential in the
colour-singlet channel.Comment: 36 pages, 11 figures, version published in Phys.Rev.
The organization and on-site follow-up of the electrical installation work for the LHC
The activity of the EL-WO section has two main purposes: manage the on-site installation works and carry out complete commissioning tests for all the new electrical installations, including those for the LHC accelerator. The management of installation works covers several aspects as: logistic, safety, coordination with other non-electrical works, follow-up of the planning. The testing of all the installation before the commissioning involves a close collaboration with the exploitation service and with the project leaders. This document describes the way of operating of the section and how these activities are carried out within the mainframe of the global ST division organization. It also describes the interfaces to the others actors of the LHC installation, such as: the contractors, the LHC installation working group, the ST/EL project leaders and the exploitation service of the electrical network
Perturbative evaluation of the eigenvalues of the Herbst Hamiltonian
We reconsider the well-known and long-debated problem of the calculation of
the eigenvalues of the Herbst Hamiltonian 2\sqrt{p^2 +m^2} - \kappa/r. We give
a formulation of the problem that allows, for the first time, a perturbative
evaluation of the eigenvalues for any n and l, and in principle up to any order
in \kappa via standard Kato perturbation theory. We present the evaluation of
the energy of the n=1 and n=2 states up to \kappa^6, confirming the result
previously obtained by Le Yaouanc et al. with a completely different technique.
Moreover we give the n=2, l=1 level, which is new. Discussion of the results
and comparison with previous findings are given at the end.Comment: 14 pages, Eq. (19) and (22) are corrected; as a consequence the
result of Eq. (26) has changed at order alpha^
The 1P quarkonium fine splittings at NLO
We calculate the 1P heavy quarkonium fine splittings at NLO and discuss the
impact of the calculation on the chi_b(1P) splittings.Comment: 10 pages, 3 figure
Heavy Quarkonium Physics-Theoretical Status
We briefly review the theoretical status and the open theoretical challenges
in the physics of heavy quarkonium.Comment: To be published in Acta Physica Polonica, based on the invited talk
given at 31st International Conference of Theoretical Physics: Matter to the
Deepest: Recent Development in Physics of Fundamental Interactions, Ustron,
Katowice, Poland, 5-11 Sep 2007. References adde
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