B. F. L. Ward

Non-tachyonic ground state for string theory

SummaryStarting from the basic open-string Lagrangian system, we apply the methods of the operator field to the center-of-mass coordinateX0. In this way, we arrive at a quantization of the open string for which the following results hold: 1) The ground state of the open string has energy 0 in the standard conventions of the method of the operator field. 2) There is no tachyon in the physical spectrum of the theory. 3) The lowest single-particle states correspond to a massless-vector state at leveln = 1 and a massive spin-2 particle of massM = 2MPlanck at leveln = 2.

Manifestly covariant, gauge-invariant interacting closed-string field theory

SummaryWe argue that Wittens covariant open-string field theory already implies its covariant closed-string field theory analog. The respective analog closedstring field theory is explicitly exhibited.

Three generations and a large top-quark mass

SummaryWe interpret the recent discovery by MkII at the SLC that the number of massless neutrino generations is 3 to mean that the family symmetry is indeedSU(3), so that our «low energy» symmetry group isSU(2)L×U1×SU(3)c×SU(3)f, where low now means small compared to the Planck mass. A possible model with a large top-quark mass is exhibited. The model is made complete by analogy with the originalSU(3)flavor model of Gell-Mann. In fact, if the latter analogy is pursued literally, it leads tomt≅65.8−8.5+39.7 GeV. Such a value is currently still viable.

On the ground state of string theory

SummaryThe following results are established for the open string: 1) The ground state of the open string has energy 0 in the standard conventions of the method of the operator field. 2) There is no tachyon in the physical spectrum of the theory. 3) The lowest single-particle states correspond to a massless vector state at leveln=1 and a massive spin-2 particle of massM=2MPlanck at leveln=2.

QSGCD: Quantum supergravichromodynamics

SummaryWe extend the methods of ’t Hooft for the planar model of QCD to their natural supersymmetric generalizations for a pure SUSY Yang-Mills theory with gauge group ℐ. We find, to leading order in the infrared and coupling constant expansions in the respective Dyson-Schwinger and Bethe-Salpeter equations, a massless SUSY multiplet of spins (2,3/2). Following Weinberg, Grisaru and Pendleton, and Kugo and Uehara, we identify this multiplet with the graviton and the gravitino in the spirit of the Sudarshan-Flatoet al. interpretation of the Weinberg-Witten theorem. We propose, therefore, that quantum gravity is really the low-energy remnant of a more fundamental theory: a SUSY Yang-Mills theory with scale parameterΛQSGCD∼MP, whereMP is the Planck mass. The true unification of gravity with the strong, weak and electromagnetic interactions occurs at a scaleMSSU⋍1·1021 GeV in anE8 example, whereE8 is the gauge group of the world. Possible connections with the superstring theories of Green and Schwarz and of Grosset al. are discussed.RiassuntoSi estendono i metodi di ’t Hooft per il modello planare di QCD alle loro generalizzazioni naturali supersimmetriche per una teoria pura SUSY di Yang-Mills con gruppo di gauge ℐ. Si trova, nell’ordine principale nell’infrarosso e negli sviluppi della costante di accoppiamento nelle rispettive equazioni di Dyson-Schwinger e di Bethe-Salpeter, un multipletto senza massa SUSY di spin (2, 3/2). Seguendo Weinberg, Grisaru e Pendleton, e Kugo e Uehara, si identifica questo multipletto con il gravitone e il gravitino nello spirito dell’interpretazione di Sudarshan-Flatoet al. del teorema di Weinberg-Witten. Si propone, perciò, che la gravità quantistica sia realmente il rimanente a bassa energia di una teoria piú fondamentale: una teoria SUSY di Yang-Mills con parametro di scalaΛQSGCD∼MP, doveMP è la massa di Planck. La vera unificazione della gravità con le interazioni forti, deboli ed elettromagnetiche avviene a una scalaMSSU⋍1·1021 GeV in un esempioE8, doveE8 è il gruppo di gauge del mondo. Si discutono possibili connessioni con le teorie di superstring di Green e Schwarz e di Grosset al.РеэюмеМы обобшаем методы т’Хуфта для планарной модели квантовой хромодинамики на случай естественных суперсимметричных обобшений для чистой теории SUSY Янга-Миллса с калибровочной группой ℐ. Мы получаем, в старщем порядке в инфракрасном раэложении и в раэложении по константе свяэи в соответствуюших уравнениях Дайсона-Щвингера и Бете-Салпетера, беэмассовый SU-SY мультиплет для спинов (2, 3/2). Следуя Вайнбергу, Грисару и Пендлетону, и Куго и Уехара, мы идентифицируем зтот мультиплет с гравитоном и гравитино в духе интерпретации Сударщана-Флато и др. теоремы Вайнберга-Виттена. Мы предполагаем, что квантовая гравитация в действительности представляет ниэкознергетический остаток более фундаментальной теории: теории SUSY Янга-Миллса с масщтабным параметром λQSGCD ∼ Мр, где Мр есть масса Планка. Истинное общединение гравитации с сильными, слабыми и злектромагнитными вэаимодействиями происходит при рMSSU⋍ 1 · 1021 ГзВ на примере Е8, где Е8 представляет калибровочную группу мира. Обсуждаются воэможные свяэи с суперструнными теориями Грина и Щварца и Гросса и др.

Skyrmionic approach to the quark model: the value ofgA

SummaryWe discuss the value ofgA in a Skyrme-type model for quarks using chiralSU2×SU2 symmetry for simplicity. We speculate, therefore, that constituent quarks may be represented by skyrmions.RiassuntoSi discute il valore digA nel modello di tipo Skyrme per i quark usando una simmetria chiraleSU2×SU2 per semplicitE. Si ipotizza, perciò, che i quark costituenti si possono rappresentare mediante skirmioni.РеэюмеМы обсуждаем величину gл в скормионной модели для кварков. Для простоты испольэуется китальнаяSU2×SU2 симметрия.

F+ decay in SLAC lattice QCD

SummaryWe derive, in the SLAC lattice QCD theory, the relevant large-distance effective interactions for the processes

Lattice contribution to charm photoproduction momentum distributions

c + \bar s \to u + \bar d + G