Related papers: Multi-gluon helicity amplitudes with one off-shell…
In this work we report on recent progress in the calculation of open superstring scattering amplitudes, at tree level, with more than four external massless states. We also report on the corresponding terms in the low energy effective…
The one-loop diffractive amplitude for emission of two real gluons with widely different rapidities is studied in the Lipatov effective action formalism. It is shown that after integration over longitudinal momenta in the loop the resulting…
In planar N=4 SYM we study a particular class of helicity preserving amplitudes. These are scalar amplitudes whose flavor configuration is chosen in such a way that only a limited number of diagrams is allowed, which exhibit an iterative…
We employ a geometric framework to compute the leading high-energy behaviour of tree-level scattering amplitudes in theories containing $N$ Nambu-Goldstone bosons and a single Higgs-like scalar with an arbitrary potential $V$. Using these…
Recent progress in our understanding of infrared singularities of multi-parton amplitudes has shown that the simplest form of Regge factorization for high-energy gauge-theory amplitudes fails starting at next-to-next-to-leading logarithmic…
We discuss a new classical action that enables efficient computation of the gluonic tree amplitudes but does not contain any triple point vertices. This new formulation is obtained via a canonical transformation of the light-cone Yang-Mills…
Results for four-, five-, and six-parton tree amplitudes for massive quark-antiquark scattering with gluons are calculated using the recursion relations of Britto, Cachazo, Feng, and Witten. The required diagrams are generated using shifts…
In AdS/CFT, we introduce a robust method for computing $n$-point gluon Mellin amplitudes, applicable in various spacetime dimensions. Using the Mellin transform and a recursive algorithm, we efficiently calculate tree-level gluon…
We consider a Higgs boson coupled to gluons via the five-dimensional effective operator H tr G_{\mu\nu}G^{\mu\nu}. We treat H as the real part of a complex field phi that couples to the selfdual gluon field strengths and compute the…
Using cutting techniques we obtain the two-loop N=4 super-Yang-Mills helicity amplitudes for four-gluon scattering in terms of scalar integral functions. The N=4 amplitudes are considerably simpler than corresponding QCD amplitudes and…
We explicitly compute the (NS) sector conventional type-I superstring tree-level amplitudes at five points after compactifying to 4-D, express the QFT building block in the helicity basis, and give several attempts towards arbitrary $n$…
We present a calculation of the helicity amplitudes for the process $gg\to\gamma\gamma$ in three-loop massless QCD. We employ a recently proposed method to calculate scattering amplitudes in the 't Hooft-Veltman scheme that reduces the…
We describe techniques that simplify the calculation of one-loop QCD amplitudes with many external legs, which are needed for next-to-leading-order (NLO) corrections to multi-jet processes. The constraints imposed by perturbative unitarity,…
We present analytic forms of three-loop four-gluon planar amplitudes in pure Yang-Mills theory in this letter. Gauge invariant bases and a set of proper master integrals are chosen such that the amplitudes are explicitly invariant under…
Any gravitational scattering amplitude takes a remarkably simple factorized form at tree level in multi-Regge kinematics (MRK), where the produced particles are strongly ordered in rapidity. Very recently, it was shown that also the…
We analyze the off-shell scattering amplitudes in the framework of the light-front perturbation theory. It is shown that the previously derived recursion relation between tree level off-shell amplitudes in this formalism actually resums…
The helicity amplitudes for the transitions $N-S_{11}$ and $N-S_{31}$ are presented. The amplitudes have been obtained within our front-form CQM model, based on hadron eigenstates of a relativistic mass operator and CQ current with Dirac…
Tree amplitudes of any gauge theory and gravity can be factorized into primitive three-particle amplitudes by the BCFW recursion relations. We show that the amplitudes at any perturbation order are given by tree amplitudes with additional…
In the 5-component representation of weak bosons, the first four components make a Lorentz four vector, representing the transverse and longitudinal polarizations excluding the scalar component of the weak bosons, whereas its fifth…
We calculate the independent helicity amplitudes in the decays B --> K^* ell^+ ell^- and B --> rho ell nu_ell in the so-called Large-Energy-Effective-Theory (LEET). Taking into account the dominant O(alpha_s) and SU(3) symmetry-breaking…