Instanton effects and chiral symmetry breaking in QCD2

We discuss the spontaneous breakdown of chiral symmetry in Quantum Chromodynamics by considering gluonic instanton configurations in the partition function. It is shown that in order to obtain nontrivial fermionic correlators in a two dimensional gauge theory for the strong interactions among quarks, a regular instanton background has to be taken into account. We work over massless quarks in the -fundamental- representation of SU(N_c). For large N_c, massive quarks are also considered.Comment: 4 pages, uses espcrc2.sty (attached), updated reference

CHR as grammar formalism. A first report

Grammars written as Constraint Handling Rules (CHR) can be executed as efficient and robust bottom-up parsers that provide a straightforward, non-backtracking treatment of ambiguity. Abduction with integrity constraints as well as other dynamic hypothesis generation techniques fit naturally into such grammars and are exemplified for anaphora resolution, coordination and text interpretation.Comment: 12 pages. Presented at ERCIM Workshop on Constraints, Prague, Czech Republic, June 18-20, 200

Particle Identification Studies with an ALICE Test TPC

Using a test TPC, consisting of the ALICE TPC field cage prototype in combination with the final ALICE TPC readout and electronics, the energy loss distribution and resolution were measured for identified protons. The measurements were compared to theoretical calculations and good quantitative agreement was found when detector effects were taken into account. The implications for particle identification are discussed.Comment: 6 pages, 4 figures, Quark Matter 06 poster proceedin

Some upper bounds on the number of resonances for manifolds with infinite cylindrical ends

We prove some sharp upper bounds on the number of resonances associated with the Laplacian, or Laplacian plus potential, on a manifold with infinite cylidrical ends

Characterization of a Maximum Likelihood Gamma-Ray Reconstruction Algorithm for VERITAS

We characterize the improved angular and energy resolution of a new likelihood gamma-ray reconstruction for VERITAS. The algorithm uses the average photoelectrons stored in templates that are based on simulations of large numbers of showers as a function of 5 gamma-ray parameters: energy, zenith angle, core location (x,y), and depth of first interaction in the atmosphere. Comparing the template predictions of the average photoelectrons in each pixel to observed photoelectrons allows us to calculate the likelihood. By maximizing the likelihood, we find the optimal gamma-ray parameters. The maximum likelihood reconstruction improves on the standard VERITAS analysis which relies on: 1. the weighted average of the axis of elongation in the images to determine the gamma-ray direction and 2. look-up tables that relate the observed energy deposition of Cherenkov photons to the true gamma-ray energy. Not only is the maximum likelihood method more accurate, but it is also not biased by missing pixel information due to the edge of the camera or pixel cleaning. The drawback is that it takes more CPU time (80 ms/event).Comment: 8 pages, 7 figures, In Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan (South Korea