121508600
Reggeon phases and the dual bootstrap program
Abstract Analyticity requirements lead to complex Regge vertices in multiparticle production amplitudes. Their effect is discussed within a dual, unitary and exchange-degenerate multi-Regge model. A resulting complex Regge vertex is incorporated in fixed-t model calculations of the reggeon bootstrap and the topological pomeron. The bootstrap condition for particle-particle scattering is unaffected but new j-plane singularities appear in Regge-Regge scattering amplitudes. The pomeron and reggeon intercepts determine the two parameters of our Regge vertex and admit two possible solutions: one is close to the naive phase rule (real vertex) and the other is complex and leads to a high lying non-leading pole in the pomeron channel.
122621587
MESON AND BARYON RESONANCES IN RELATIVISTIC SU(6)
43381389
Glueball calculations with the t expansion.
We discuss the way glueball states can be calculated using the t-expansion technique for the SU(3) lattice gauge theory in 3+1 space-time dimensions. Starting with strong-coupling wave functions we specify the simplest glueball structures that can be analyzed. They are described in a general group-theoretical language. We also present an alternative construction in terms of electric and magnetic fields. We then explain the use of the connected matrix formalism for this problem and discuss the results for the ${0}^{++}$ and ${1}^{+\mathrm{\ensuremath{-}}}$ glueballs that have been analyzed before. We present new results for ${0}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{-}}}$, ${1}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{-}}}$, and ${2}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{-}}}$ glueballs, for which we calculated the t expansion to order ${t}^{6}$. They exhibit a scaling behavior leading to masses which are of the order of twice that of the scalar glueball.
6547578
The t expansion and SU(3) lattice gauge theory.
This paper presents the first results obtained by applying the t expansion to the case of an SU(3) lattice gauge theory in 3+1 space-time dimensions. We apply to this problem the same techniques which have been successfully used in the analysis of the SU(2) theory. We test their effectiveness first on the one-plaquette SU(3) problem, and conclude that even a moderate series in t suffices to reach the weak-coupling domain. We then compute the t expansion of the vacuum energy density to order t/sup 8/ and find from our analysis the behavior of this quantity as a function of the coupling constant. From the same series we obtain the mass M of the lowest-lying 0/sup + +/ glueball to order t/sup 6/. Evaluating the string tension sigma to the same order we construct the ratio R = M/sup 2//sigma which allows us to obtain a dimensional result for M which is consistent with Monte Carlo analyses.
39663223
Frustrated spin Hamiltonians with binary input vectors.
Structures of composite spin operators are analyzed which appear in models of neural networks of the type which Amit et al. have recently investigated. A binary basis of size N${=2}^{M}$ is introduced to study a problem of N quantum-mechanical spin operators. The [Z${(2)]}^{M}$ group structure of the binary basis allows for many decompositions of the [SU(2)${]}^{\mathrm{N}}$ spin algebra. These become useful in studying and solving generalized frustrated Heisenberg as well as Ising models. Using these techniques for quantum-mechanical generalized spin operators, we derive an explicit representation of the partition function of classical statistical-mechanics models, in terms of a series summation over components of collective spin variables.
119442708
Gauge-invariant variational methods for Hamiltonian lattice gauge theories
This paper develops variational methods for calculating the ground-state and excited-state spectrum of Hamiltonian lattice gauge theories defined in the A/sub 0/ = 0 gauge. The scheme introduced in this paper has the advantage of allowing one to convert more familiar tools such as mean-field, Hartree-Fock, and real-space renormalization-group approximation, which are by their very nature gauge-noninvariant methods, into fully gauge-invariant techniques. We show that these methods apply in the same way to both Abelian and non-Abelian theories, and that they are at least powerful enough to describe correctly the physics of periodic quantum electrodynamics (PQED) in (2+1) and (3+1) space-time dimensions. This paper formulates the problem for both Abelian and non-Abelian theories and shows how to reduce the Rayleigh-Ritz problem to that of computing the partition function of a classical spin system. We discuss the evaluation of the effective spin problem which one derives the PQED and then discuss ways of carrying out the evaluation of the partition function for the system equivalent to a non-Abelian theory. The explicit form of the effective partition function for the non-Abelian theory is derived, but because the evaluation of this function is considerably more complicated than the one derived in the Abelianmore » theory no explicit evaluation of this function is presented. However, by comparing the gauge-projected Hartree-Fock wave function for PQED with that of the pure SU(2) gauge theory, we are able to show that extremely interesting differences emerge between these theories even at this simple level. We close with a discussion of fermions and a discussion of how one can extend these ideas to allow the computation of the glueball and hadron spectrum.« less
125542777
Measurement of the Exclusive and Inclusive Branching Fractions of $B^{0}_{s} \to D^{(*)+}_{s}D^{(*)-}_{s}$ Decays at CDF and its Implications on the Decay Width Difference in the $B^{0}_{s}-B^{-0}_{s}$ Meson System
118159758
Study of $B^{0}_{s} \rightarrow D_s^{(*)+}D_s^{(*)-}$ and $B^{0}_{s} \rightarrow \phi\phi$ Decays at CDF
Under certain theoretical assumptions, the branching fraction of B{sub s}{sup 0} {yields} D{sub s}{sup (*)+}D{sub s}{sup (*)-} is directly sensitive to the relative decay width difference {Delta}{Lambda}{sub s}{sup CP}/{Lambda}{sub s} in the B{sub s}{sup 0} system, which is predicted to be sizable in the standard model. Using approximately 4 fb{sup -1} of data collected by the CDF II detector at the Tevatron p{bar p} collider, the CDF collaboration is currently performing an exclusive selection of B{sub s}{sup 0} {yields} D{sub s}{sup (*)+}D{sub s}{sup (*)-} signal candidates in several hadronic modes in order to provide a new branching fraction measurement. In contrast to former analyses, we start to have sensitivity in disentangling D{sub s}{sup (*)+}D{sub s}{sup (*)-}, enabling us to measure the branching fractions of B{sub s}{sup 0} {yields} D{sub s}{sup +}D{sub s}{sup -}, B{sub s}{sup 0} {yields} D{sub s}{sup (*)+}D{sub s}{sup -} and B{sub s}{sup 0} {yields} D{sub s}{sup (*)+}D{sub s}{sup (*)-} separately. Yet another interesting mode is the decay of the B{sub s}{sup 0} into a {phi} pair. This is a vector-vector decay dominated by the b {yields} s{ovr ss} penguin transition, which is a sensitive probe for possible new physics effects. Here we present a new measurement ofmore » the branching fraction based on a clean sample of about 300 B{sub s}{sup 0} {yields} {phi}{phi} signal events in a dataset with an integrated luminosity of 2.9 fb{sup -1}.« less