11337046
D-branes in Landau-Ginzburg models and algebraic geometry
We study topological D-branes of type B in N = 2 Landau-Ginzburg models, focusing on the case where all vacua have a mass gap. In general, tree-level topological string theory in the presence of topological D-branes is described mathematically in terms of a triangulated category. For example, it has been argued that B-branes for an N = 2 sigma-model with a Calabi-Yau target space are described by the derived category of coherent sheaves on this space. M. Kontsevich previously proposed a candidate category for B-branes in N = 2 Landau-Ginzburg models, and our computations confirm this proposal. We also give a heuristic physical derivation of the proposal. Assuming its validity, we can completely describe the category of B-branes in an arbitrary massive Landau-Ginzburg model in terms of modules over a Clifford algebra. Assuming in addition Homological Mirror Symmetry, our results enable one to compute the Fukaya category for a large class of Fano varieties. We also provide a (somewhat trivial) counter-example to the hypothesis that given a closed string background there is a unique set of D-branes consistent with it.
115635245
Topological sigma models and generalized geometries
We study the relation between topological sigma models and generalized geometries. The existence conditions for the most general type of topological sigma models obtained from twisting the N=(2,2) supersymmetric sigma model are investigated, and are found to be related to twisted generalized Calabi-Yau structures. The properties of these topological sigma models are analyzed in detail. The observables are shown to be described by the cohomology of a Lie algebroid, which is intrinsically associated with the twisted generalized Calabi-Yau structure. The Frobenius structure on the space of states and the effects of instantons are analyzed. We also study D-branes in these topological sigma models, and demonstrate that they also admit descriptions in terms of generalized geometries.
18559665
Topological sigma-models with H-flux and twisted generalized complex manifolds
We study the topological sector of N = 2 sigma-models with HH-flux. It has been known for a long time that the target-space geometry of these theories is not Kahler and can be described in terms of a pair of complex structures, which do not commute, in general, and are parallel with respect to two different connections with torsion. Recently an alternative description of this geometry was found, which involves a pair of commuting twisted generalized complex structures on the target space. In this paper, we define and study the analogs of A and B-models for N = 2 sigma-models with HH-flux and show that the results are naturally expressed in the language of twisted generalized complex geometry. For example, the space of topological observables is given by the cohomology of a Lie algebroid associated to one of the two twisted generalized complex structures. We determine the topological scalar product, which endows the algebra of observables with the structure of a Frobenius algebra. We also discuss mirror symmetry for twisted generalized Calabi-Yau manifolds.
123491963
Noncoplanarity in proton-proton bremsstrahlung
Using the soft-photon approximation, we address the issue of the importance of noncoplanarity effects in proton-proton bremsstrahlung, We investigate the noncoplanar cross section as a function of the noncoplanarity angle (φ) over bar for the entire range of the photon polar angle psi(gamma). The (φ) over bar dependence is shown to provide a significant variation in the cross section, for a given psi(gamma). Thus, there can be some uncertainty in determining experimental coplanar cross sections. To avoid the phase-space singularities of spherical geometry. we utilize the Harvard noncoplanar geometry. A detailed explication of the Harvard geometry is provided, Comparison of our calculations with experimental data is included.
13345134
D-branes in topological minimal models: the Landau–Ginzburg approach
We study D-branes in topologically twisted N = 2 minimal models using the Landau-Ginzburg realization. In the cases of A and D-type minimal models we provide what we believe is an exhaustive list of topological branes and compute the corresponding boundary OPE algebras as well as all disk correlators. We also construct examples of topological branes in E-type minimal models. We compare our results with the boundary state formalism, where possible, and find agreement.
123079556
Reply to "Comment on 'Noncoplanarity effects in proton-proton bremsstrahlung' "
We respond to the Comment by Huisman and Kalantar-Nayestanaki [Phys. Rev. C 64, 029801 (2001)]. In particular, we point out that the proposal to present noncoplanar proton-proton bremsstrahlung data as squared matrix elements involves unresolved theoretical problems.
123193403
The rate of the sphaleron transition in the (1 + 1)-dimensional Abelian Higgs model on a circle
Abstract The rate of fermion number non-conservation at finite temperatures is discussed in the (1 + 1)-dimensional Abelian Higgs model on a circle. An effective potential is used to estimate the one-loop correction to the effective action remaining after the treatment of zero modes. With this method it is not necessary to know all the normal modes of the sphaleron. The expression of the rate is given for the case of M W ⪡ M H .
58938119
Exclusive soft function for Drell-Yan at next-to-next-to-leading order
We present next-to-next-to-leading-order (NNLO) results for an exclusive soft function that appears in a recently developed factorization theorem for transverse momentum distributions. The factorization theorem, derived using the Soft Collinear Effective Theory, involves both a soft function and unintegrated nucleon distribution functions fully differential in momentum coordinates. The soft function is given by the vacuum matrix element of soft Wilson lines and is also fully differential in all components. We give results and relevant technical details for the NNLO calculation of the soft function, including finite parts, and derive the corresponding anomalous dimension. These results are necessary for achieving low transverse momentum resummation at next-to-next-to-leading-logarithmic accuracy in this effective field theory approach with unintegrated distribution functions.
7025505
Exact Analysis of Scaling and Dominant Attractors Beyond the Exponential Potential
By considering the potential parameter Γ as a function of another potential parameter λ (Zhou et al 2008 Phys. Lett. B 660 7–12), we successfully extend the analysis of a two-dimensional autonomous dynamical system of a quintessence scalar field model to the analysis of a three-dimensional system, which enables us to study the critical points of a large number of potentials beyond the exponential potential exactly. We find that there are ten critical points in all, three points P3,5,6 are general points which are possessed by all quintessence models regardless of the form of potentials and the rest of the points are closely connected to the concrete potentials. It is quite surprising that, apart from the exponential potential, there are a large number of potentials which can give a scaling solution when the function f(λ)(=Γ(λ) − 1) equals zero for one or some values of λ and if the parameter λ also satisfies condition (16) or (17) at the same time. We give the differential equations to derive these potentials V() from f(λ). We also find that, if some conditions are satisfied, the de-Sitter-like dominant point P4 and the scaling solution point P9 (or P10) can be stable simultaneously unlike P9 and P10. Although we survey scaling solutions beyond the exponential potential for ordinary quintessence models in standard general relativity, this method can be applied to other extensively scaling solution models studied in the literature (Copeland et al 2006 Int. J. Mod. Phys. D 15 1753) including coupled quintessence, (coupled-)phantom scalar field, k-essence and even beyond the general relativity case H2 ∝ ρnT. We also discuss the disadvantage of our approach.
119023320
Sum rules and spin-dependent polarizabilities of the deuteron in effective field theory
We construct sum rules for the forward vector and tensor polarizabilities for any spin-S target and apply them to the spin-1 deuteron. We calculate these polarizabilities of the deuteron to the next-to-leading order in the pionless effective field theory.
119211752
Single soft gluon emission at two loops
A bstractWe study the single soft-gluon current at two loops with two energetic partons in massless perturbative QCD, which describes, for example, the soft limit of the two-loop amplitude for gg → Hg. The results are presented as Laurent expansions in ϵ in D = 4 − 2ϵ spacetime dimension. We calculate the expansion to order ϵ2 analytically, which is a necessary ingredient for Higgs production at hadron colliders at next-to-next-to-next-to-leading order in the soft-virtual approximation. We also give two-loop results of the single soft-gluon current in $ \mathcal{N}=4 $ Super-Yang-Mills theory, and find that it has uniform transcendentality. By iteration relation of splitting amplitudes, our calculations can determine the three-loop single soft-gluon current to order ϵ0 in $ \mathcal{N}=4 $ Super-Yang-Mills theory in the limit of large Nc.