Ninth Workshop on Non-Perturbative Quantum Chromodynamics

Arotisenet, Pierre: “Heavy Quarkonium Production in Hadron Collisions” In this talk, I will discuss heavy quarkonium production in the framework of Non-Relativistic Quantum ChromoDynamics. I will briefly describe the main features of this theory, highlighting both the successes and the current open questions in quarkonium production in collider experiments. I will next move on to an updated analysis of J/psi production at Tevatron, considering the recently calculated NLO contributions to heavy quarkonium production via color singlet transitions. Finally I will comment on the implications of the current data on the non-perturbative dynamics in heavy quarkonium production. Balitsky, Ian: “Small-x Evolution of Color Dipoles in the Next-to-Leading Order” The small-x deep inelastic scattering in the saturation region is governed by the non-linear evolution equation for Wilson-lines operators. In the leading logarithm approximation it is given by the BK equation for the evolution of color dipoles. I present the results of the next-to-leading order calculation and discuss the argument of the coupling constant in the BK equation. Bender, Carl: “Faster than Hermitian Quantum Mechanics” Given initial and final quantum states |I > and |F >, there exist Hamiltonians H under which evolves into |F >. The quantum brachistochrone problem is to find the Hamiltonian that achieves this transformation in the least time τ , subject to the constraint that the difference between the largest and smallest eigenvalues of H is held fixed. For Hermitian Hamiltonians τ has a nonzero lower bound. However, for non-Hermitian PT-symmetric Hamiltonians satisfying the same energy constraint, τ can be made arbitrarily small. This does not violate the time-energy uncertainty principle because for such Hamiltonians the path from |I > to |F > can be made short. The mechanism is similar to that in general relativity in which the distance between two space-time points can be made small if they are connected by a wormhole. This result may have applications in quantum computing. Brandhuber, Andreas: “Refining MHV Diagrams” It has been known for some time that the standard MHV diagram formulation of perturbative Yang-Mills theory is incomplete, as it misses rational terms in one-loop scattering amplitudes of non-supersymmetric Yang-Mills. In this talk we review recent ideas that circumvent this limitation. In particular, we propose that certain Lorentz violating counterterms, when expressed in the field variables which give rise to standard MHV vertices, produce precisely these missing terms. These counterterms appear when Yang-Mills is treated with a regulator, introduced by Thorn and collaborators. As an illustration we show that a simple one-loop, two-point counterterm is the generating function for the infinite sequence of one-loop, all-plus helicity amplitudes in pure Yang-Mills, in complete agreement with known expressions. Brower, Richard: “AdS Graviton Exchange at High Energies”