NONPERTURBATIVE EFFECTS IN OPERATOR PRODUCT EXPANSION AS THE ORIGIN OF THE ENHANCEMENT FACTORS IN THE ρ-MESON QCD SUM RULE

title: AN IMPROVED EFFECTIVE POTENTIAL APPROACH TO DYNAMICAL SYMMETRY BREAKING
abstract: We have developed, in this paper, a method for evaluating effective potential for local composite fields based on loop expansion by first renormalizing the generating functional of connected Green's functions and then making the Legendre transformation. A consistency condition reflecting the fact that no condensate effect occurs at tree level is proposed, which plays an important role in this method. The method is illustrated through the Gross-Neveu model. This method can be applied to a wider class of models than can the auxiliary field method.

title: Longitudinal/Goldstone boson equivalence and phenomenology of probing the electroweak symmetry breaking
abstract: We formulate the equivalence between the longitudinal weak-boson and the Goldstone boson as a criterion for sensitively probing the electroweak symmetry breaking mechanism and develop a precise power counting rule for chiral Lagrangian formulated electroweak theories. With these we semi-quatitatively analyze the sensitivities to various effective operators related to electrowaeak symmetry breaking via weak-boson scatterings at the CERN Large Hadron Collider (LHC).

title: Derivation of the Gasser-Leutwyler Lagrangian from QCD
abstract: The normal part of the Gasser-Leutwyler formulation of the chiral Lagrangian is formally derived from the first principles of QCD without taking approximations. All the coefficients are expressed in terms of certain Green's functions in QCD, which can be regarded as the general QCD definitions of the normal part of the coefficients. The approximate values of the coefficients are also presented.

title: FORMAL DERIVATION OF THE CHIRAL LAGRANGIAN FOR PSEUDOSCALAR MESONS FROM QUANTUM CHROMODYNAMICS

title: Dynamical breakdown of supersymmetry and chiral symmetry in 1+1 dimensions
abstract: Dynamical breakdown of supersymmetry and chiral symmetry is studied through a 1+1 dimensional field theoretical model in the large-N limit in 1/N expansion. The study is based on the calculation of bilinear field condensates in an effective potential approach. It is shown that the condition for supersymmetry breaking is related to the values of the parameters in the model and chiral symmetry breaking exists in most cases.

title: Search for the presence of H particles in a neutral beam
abstract: A search was made to detect the presence of long-lived H particles in a neutral beam by diffractive dissociation into two lambda particles. Preliminary results are presented.

title: A compact beam stop for a rare kaon decay experiment
abstract: We describe the development and testing of a novel beam stop for use in a rare kaon decay experiment at the Brookhaven Alternating Gradient Synchrotron. The beam stop is located inside a dipole spectrometer magnet in close proximity to straw drift chambers and intercepts a high-intensity neutral hadron beam. The design process, involving both Monte Carlo simulations and beam tests of alternative beam-stop shielding arrangements, had the goal of minimizing the leakage of particles from the beam stop and the resulting hit rates in detectors, while preserving maximum acceptance for events of interest. The beam tests consisted of measurements of rates in drift chambers, scintillation counter hodoscopes, a gas threshold Cherenkov counter, and a lead glass array. Measurements were also made with a set of specialized detectors which were sensitive to low-energy neutrons, photons, and charged particles. Comparisons are made between these measurements and a detailed Monte Carlo simulation.

title: A straw drift chamber spectrometer for studies of rare kaon decays
abstract: We describe the design, construction, readout, tests, and performance of planar drift chambers, based on 5-mm-diameter copperized Mylar and Kapton straws, used in an experimental search for rare kaon decays. The experiment took place in the high-intensity neutral beam at the Alternating Gradient Synchrotron of Brookhaven National Laboratory, using a neutral beam stop, two analyzing dipoles, and redundant particle identification to remove backgrounds.

title: First observation of the rare decay mode K0(L) ---> e+ e-
abstract: In an experiment designed to search for and study very rare two-body decay modes of the K-long, we have observed four examples of the decay K-long -> e+ e-, where the expected background is 0.17+-0.10 events. This observation translates into a branching fraction of 8.7^{+5.7}_{-4.1} X 10^{-12}, consistent with recent theoretical predictions. This result represents by far the smallest branching fraction yet measured in particle physics.

title: Higher statistics measurement of the branching ratio for the decay K0(L) ---> mu mu