HIGH ENERGY PHYSICS: The 25th Annual MontrealRochesterSyracuseToronto Conference on High Energy Physics MRST 2003: A Tribute to Joe Schechter

Unnatural Acts: Unphysical Consequences of Imposing Boundary Conditions on Quantum Fields
View Description Hide DescriptionI examine the effect of trying to impose a Dirichlet boundary condition on a scalar field by coupling it to a static background. The zero point — or Casimir — energy of the field diverges in the limit that the background forces the field to vanish. This divergence cannot be absorbed into a renormalization of the parameters of the theory. As a result, the Casimir energy of a surface on which a Dirichlet boundary condition is imposed, and other quantities like the surface tension, which are obtained by deforming the surface, depend on the physical cutoffs that characterize the coupling between the field and the matter on the surface. In contrast, the energy density away from the surface and forces between rigid surfaces are finite and independent of these complications.

Lepton‐Hadron Symmetry and Neutrino Masses
View Description Hide DescriptionLepton‐quark symmetry, although badly broken, leads to the conclusion that neutrinos have masses and mixings. These have now been discovered but there is more experimental information needed and a fundamental theory is still lacking.

Neutrino masses twenty‐five years later
View Description Hide DescriptionThe discovery of neutrino mass marks a turning point in elementaary particle physics, with important implications for nuclear and astroparticle physics. Here I give a brief update, where I summarize the current status of three‐neutrino oscillation parameters from current solar, atmospheric, reactor and accelerator neutrino data, discuss the case for sterile neutrinos and LSND, and also the importance of tritium and double beta decay experiments probing the absolute scale of neutrino mass. In this opininated look at the present of neutrino physics, I keep an eye in the future, and a perspective of the past, taking the oportunity to highlight Joe Schechter’s pioneering contribution, which I have had the fortune to share, as his PhD student back in the early eighties.

Construction of Lie Superalgebras from Triple Product Systems
View Description Hide DescriptionAny simple Lie superalgebras over the complex field can be constructed from some triple systems. Examples of Lie superalgebras D(2, 1; α), G(3) and F(4) are given by utilizing a general construction method based upon (−1, −1) balanced Freudenthal‐Kantor triple system.

Yang‐Mills Theory on Loop Space
View Description Hide DescriptionWe will describe some mathematical ideas of K. T. Chen on calculus on loop spaces. They seem useful to understand non‐abelian Yang‐Mills theories.

Chiral Lagrangian Treatment of the Scalar Mesons: an Overview
View Description Hide DescriptionIn this talk a brief overview of the chiral Lagrangian framework for scalar mesons of refs. [1, 2, 3, 4, 5, 6, 7, 8] together with several low energy processes that have been studied in this framework, is presented.

Magnetic Moments of Baryons with a Heavy Quark
View Description Hide DescriptionWe compute magnetic moments of baryons with a heavy quark in the bound state approach for heavy baryons. In this approach the heavy baryon is considered as a heavy meson bound to a light baryon. The latter is represented as a soliton excitation of light meson fields. We obtain the magnetic moments by sandwiching pertinent components of the electromagnetic current operator between the bound state wave‐functions. We extract this current operator from the coupling to the photon field after extending the action to be gauge invariant.

Poles of light resonances from unitarized Chiral perturbation Theory and their large N_{c} behavior
View Description Hide DescriptionWe have recently completed the one loop calculation of meson‐meson scattering within Chiral Perturbation Theory. Once unitarized, these amplitudes provide simultaneously a remarkable description of the resonance region up to 1.2 GeV as well as the low energy region, respecting the chiral symmetry expansion. The position of the poles in these amplitudes is related to the mass and width of the associated resonances that are generated without being explicitly included in the Lagrangian. The spectroscopic nature of these states can then be deduced by studying the behavior of these poles, through the N_{c} dependence of the Chiral Perturbation Theory parameters, which can be obtained from QCD in the large N_{c} limit.

Explaining the
View Description Hide DescriptionThe recently observed meson is explained as a scalar cs̄ system which appears as a bound state pole, below threshold, in the DK scattering amplitude. The standard cs̄ charmed scalar D _{ s0} is found at about 2.9 GeV, with a width of some 150 MeV.

Observation of the D_{sJ} (2463) and Confirmation of the
View Description Hide DescriptionUsing 13.5 fb^{−1} of e^{+}e^{−} annihilation data in the CLEO II detector at CESR, we have observed a new narrow state decaying to , denoted the D_{sJ} (2463)^{+}. A possible interpretation holds that this is a J^{P} = 1^{+} partner to the state recently discovered by the BaBar Collaboration which is consistent with J^{P} = 0^{+}. We have also confirmed the existence of the in its decay to . We have measured the masses of both states, accounting for the cross‐feed background that the two states represent for each other, and have searched for other decay channels for both states. No narrow resonances are seen in or modes.

Multi‐Spin String Solutions and AdS/CFT Correspondence
View Description Hide DescriptionExtension of the AdS/CFT duality to non‐BPS states requires studying classical closed string solutions with several angular momenta in different directions of AdS _{5} and S ^{5}. We find a novel solution describing a circular closed string located at a fixed value of AdS _{5} radius while rotating simultaneously in two planes in AdS _{5} with equal spins S. Similar solution exists for a string rotating in S ^{5}: it is parametrized by the angular momentum J of the center of mass and two equal SO(6) angular momenta J _{2} = J _{3} = J′ in the two rotation planes. We discuss interpolation of the E(J,J′) formula to weak coupling by identifying the gauge theory operator that should be dual to the corresponding semiclassical string state. This opens up a possibility of studying AdS/CFT duality in this new non‐BPS sector.

Edge Currents in Non‐commutative Chern‐Simons Theory
View Description Hide DescriptionIn this paper we report on the formulation of the non‐commutative Chern‐Simons (CS) theory where the spatial slice, an infinite strip, is a manifold with boundaries. Our approach involves the formulation of a new finite‐dimensional matrix model which approximates the CS theory on the non‐commmutative strip. This model has a fuzzy edge which becomes the required sharp edge when size of the matrices approaches infinity. The non‐commutative CS theory on the strip is defined by this limiting procedure. The canonical analysis of the matrix theory reveals that there are edge observables in the theory generating a Lie algebra with properties similar to that of a non‐abelian Kac‐Moody algebra. Using some of the results of this analysis we discuss in detail the limit where this matrix model approximates the CS theory on the infinite strip.

Vector Manifestation in Hot Matter and Violation of Vector Dominance
View Description Hide DescriptionWe summarize main mechanisms to realize the vector manifestation (VM), in which the massless vector meson becomes the chiral partner of pion, at the critical temperature in hot QCD within the framework of the model based on the hidden local symmetry. Then, we show a recent analysis on the direct photon‐π‐π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion: The VM predicts that the VD is largely violated at the critical temperature.

Higgs Mechanism via Bose‐Einstein Condensation
View Description Hide DescriptionRecently the Bose‐Einstein phenomenon has been proposed as possible physical mechanism underlying the spontaneous symmetry breaking in cold gauge theories. The mechanism is natural and we use it to drive the electroweak symmetry breaking. The mechanism can be implemented in different ways while here we review two simple models in which the Bose‐Einstein sector is felt directly or indirectly by all of the standard model fields. The structure of the corrections due to the new mechanism is general and independent on the model used leading to experimental signatures which can be disentangled from other known extensions of the standard model.

Spontaneous CP violation in the U (3) NJL model
View Description Hide DescriptionWith the help of the functional integration method, the formation of scalar, pseudoscalar condensates, and dynamical symmetry breaking in the U (3) four‐fermion model have been investigated. We show the possibility of spontaneous CP symmetry violation in the model under consideration. The bosonization procedures of the model are performed; the propagators of quarks, scalar and pseudoscalar fields are calculated in one loop approximation. The masses of the scalar and pseudoscalar mesons are evaluated.

Anomalies and the Large N Limit
View Description Hide DescriptionOperator algebra aspects of the Large N limit of Bosonic vector models are analyzed. It is shown that the Large N limit is a classical theory, and a general method, based on defromation quatization, for calculating the Poisson algebra of dynamical observables in the limiting classical theory is presented. The Poisson algebra of O(N) invariant observables of Bosonic vector models is constructed in this approach, and is shown to be a central extension of the Symplectic Lie algebra. The relation of the central term to anomalies is discussed. A comparision of the classical theories obtained in the Large N limit and that in the small ℏ limit is also presented.

Consequences of Leading‐Logarithm Summation for the Radiative Breakdown of Standard‐Model Electroweak Symmetry
View Description Hide DescriptionIn the empirically sensible limit in which QCD, t‐quark Yukawa, and scalar‐field‐interaction coupling constants dominate all other Standard‐Model coupling constants, we sum all leading‐logarithm terms within the perturbative expansion for the effective potential that contribute to the extraction of the Higgs boson mass via radiative electroweak symmetry breaking. A Higgs boson mass of 216 GeV emerges from such terms, as well as a scalar‐field‐interaction coupling constant substantially larger than that anticipated from conventional spontaneous symmetry breaking. The sum of the effective potential’s leading logarithms is shown to exhibit a local minimum in the limit φ → 0 if the QCD coupling constant is sufficiently strong, suggesting (in a multiphase scenario) that electroweak physics may provide the mechanism for choosing the asymptotically‐free phase of QCD.

Tau‐Mu Flavor Violation and the Scale of New Physics
View Description Hide DescriptionMotivated by the strong experimental evidence of large v _{μ} ‐ v _{τ} neutrino oscillations, we study existing constraints for related μ ‐ τ flavor violation. Using a general bottom‐up approach, we construct dimension‐6 effective fermionic operators whose coefficients encode the scale of new physics associated with μ ‐ τ flavor violation, which is a piece in the puzzle of the origin of neutrino oscillations. We survey existing experimental bounds on this scale, which arise mostly from τ and B decays. In many cases the new physics scale is constrained to be above a few TeV. We also discuss the operators which are either weakly constrained or, at present, subject to no experimental bounds.

Λ_{ b } decay to Λ and η′
View Description Hide DescriptionThe two‐body hadronic decay of Λ_{ b } baryon to Λ + η′ is investigated. We estimate the nonfactorizable contribution due to the gluon fusion mechanism which could be the possible dominant process in η′ production in hadronic B decays. Our crude estimate, which is made by factorizing weak and strong vertices, point to a significant enhancement of the branching ratio due to the gluon fusion mechanism in this baryonic decay.

Supernovae as particle physics Laboratories
View Description Hide DescriptionThe possibilities of using the neutrino signal of a galactic supernova is briefly reviewed. The concept is then applied to derive bounds on the existence of a light neutralino.