M. H. Friedman

Fermions in an External SU(2) Magnetic Field

We consider fermions in a constant and uniform external SU(2) magnetic field. We find that the results for the energy levels depend on the choice of gauge. Choosing a Landau-type gauge yields results analagous to those of Abelian theories. On the other hand, using another gauge potential one obtains a different continuous eigenvalue spectrum.

Spin-zero pole dominance in the weak and electromagnetic interactions of the K-meson

SummaryThe assumption of π, η and σ dominance of the weak and electromagnetic decays of the K-meson is examined using the hard-meson current algebra amplitudes for the strong-interaction factors. The K → 3π decay spectrum, the KL0 → 2γ decay and the KL0-KS0 mass difference are calculated and compared with experiment.RiassuntoSi esamina l’ipotesi della predominanza di π, η e σ nei decadimenti deboli ed elettromagnetici del mesone K facendo uso delle ampiezze dell’algebra delle correnti del mesone duro per i fattori dell’interazione forte. Si calcolano lo spettro del decadimento K → 3π, il decadimento KL0 → 2γ e la differenza di massa KL0-KS0 e li si confrontano con i dati sperimentali.РеэюмеИспольэуя амплитуды алгебры токов жестких меэонов для факторов сильных вэаимодействий, исследуется предположение π, η и σ доминантности в слабых и злектромагнитных распадах К меэона. Вычисляются и сравниваются с зкспериментом спектр распада К → 3π, распад КL0 → 2γ и раэность масс КL0-К{S/0}.

A Lagrangian approach to dual pion amplitudes

A simple Lagrangian is constructed, which in the tree approximation produces a ππ scattering amplitude possessing (i) the correct iso-spin structure with no exotic resonances (ii) Regge asymptotic behavior Sαϱ(t) and (iii) duality and satisfies (iv) the Adler condition. The last condition is satisfied without any restriction on the Regge-trajectory intercept. However, if we set αϱ (mπ2) = 12, the present model produces all the terms in the one of Lovelace-Veneziano plus a satellite term of 0(p2mϱ2) where p is the momentum of the off-shell pion. The ratio of I = 0 to I = 2 S-wave scattering lenghts is a00a02 ≈ −2 and thus lies between the Schwinger value of −32 and the Weinberg value of −72.

Compact lattice QED and the Coulomb potential

Abstract The potential energy of a static charge distribution on a lattice is rigorously computed in the standard compact quantum electrodynamic model. The method used follows closely that of Weyl for ordinary quantum electrodynamics in continuous space-time. The potential energy of the static charge distribution is independent of temperature and can be calculated from the lattice version of Poissons equation. It is the usual Coulomb potential.

Soft-giuon corrections to the drell-yan process

SummaryThe 4-momentum distribution,, of the multiple softgluon emission is studied using a Bloch-Nordsieck approach. An asymp totic separability is found:, whereK± =K0±K3. Their effect inΜ pair production is investigated and explicit expressions for the double differential cross-section are obtained. The slope of the mean transverse momentum with total energy is calculated and com pared with data. Our mean scaling curves are also in good agreement with experiment. Further tests are suggested.RiassuntoSi studia la distribuzione del quadrimpulso dell’emissione multipla di gluoni morbidi usando un approccio di Bloch-Nordsieck. Si trova una separabilitá asintotica:, doveK± =K0±K3. Si studia il loro effetto nella produzione di coppie di → e si ottengono espressioni esplicite per la sezione d’urto doppio differenziale. Si calcola la pendenza dell’impulso medio trasversale con l’energia totale e si confronta con i dati. Le curve medie di scala sono in buon accordo con l’espe rimento. Si suggeriscono altri controlli.РЕжУМЕИспОльжУь пОДхОД БлО хА-НОРДсИкА, ИсслЕДУЕтсь РАспРЕД ЕлЕНИЕ ЧЕтыРЕхИМпУл ьсА,, Дль МНОжЕстВЕННОгО ИспУскАНИь МьгкИх гл УОНОВ. ОБНАРУжЕНА АсИМптОтИЧЕскАь РАж ДЕльЕМОсть: гДЕ K±=K0K3. ИсслЕДУЕтсь ВлИьНИЕ ИспУскАНИь МьгкИх гл УОНОВ НА РОжДЕНИЕ МУОННых пАР. пОлУЧАУтсь тОЧНыЕ ВыРАжЕНИь Дль ДВОИНОгО ДИФФЕРЕНцИ АльНОгО пОпЕРЕЧНОгО сЕЧЕНИь. ВыЧИсльЕтсь НАклОН с РЕДНЕгО пОпЕРЕЧНОгО ИМпУльсА с пОлНОИ ЁНЕРгИЕИ. пОлУ ЧЕННыИ РЕжУльтАт сРАВНИВАЕ тсь с ЁкспЕРИМЕНтАль НыМИ ДАННыМИ. НАшИ сРЕДНИЕ кРИВыЕ скЕИлИНгА тАкжЕ хОРО шО сОглАсУУтсь с Ёксп ЕРИМЕНтОМ. пРЕДлАгАУтсь ДОпОлН ИтЕльНыЕ ИсслЕДОВАНИь.

Weak currents in an internal parity model

Abstract The suggestion that there exists an “internal parity” carried by the electron and μ-meson which is multiplicatively conserved is incorporated into a spontaneously broken gauge theory of the weak and electromagnetic interactions. The inclusion of hadrons in the model requires the introduction of additional right handed couplings which accomodata the ΔI = 1 2 enhancement scheme of De Rujula et al. It also requires a “hypercharmed” quark p″ in addition to the customary p, p′, n and λ quarks. Furthermore, a set of right handed heavy charged leptons and their neutrinoes are needed to cancel anomalies.

Currents, colliding beams and the light cone

Abstract Currents of scale dimension 3 of the field-current identity type arise naturally from the principles of broken scale invariance. Applications at intermediate energy to e + + e − annihilation into four charged pions, and at high energy to light cone commutators are given.

On chiral algebra, meson dominance, and the soft-pion evaluation of gϱ☆

Abstract The derivations of g ϱ 2 = 2 F π 2 m ϱ 2 by Kawarabayashi and Suzuki and others are re-examined. It is shown that when the full content of chiral algebra is exploited, the analysis reduces to an identity rather than a determination of g ϱ .