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We present a prescription for computing the tree-level two-point amplitude of closed strings in the pure spinor superstring formalism, thereby completing the analysis of such superstring amplitudes. The construction relies on fixing the…

High Energy Physics - Theory · Physics 2025-12-30 Sitender Pratap Kashyap

We use Pure Spinor String Theory to construct suitable building blocks to arrange the structure of supergravity amplitudes with n-points and at higher loops in a very convenient way. Following Mafra et al. proposal for N=4 super Yang-Mills…

High Energy Physics - Theory · Physics 2011-07-21 P. A. Grassi , L. Sommovigo

In the Type II superstring the 4-point function for massless NS-NS bosons at one-loop is well known [1][14]. The overall constant factor in this amplitude is very important because it needs to satisfy the unitarity and S-duality conditions…

High Energy Physics - Theory · Physics 2010-02-04 Humberto Gomez

We find a direct map that determines moduli-space integrands for one-loop superstring amplitudes in terms of field-theory loop integrands in the BCJ form. The latter can be computed using efficient unitarity methods, so our map provides an…

High Energy Physics - Theory · Physics 2025-02-05 Yvonne Geyer , Jiachen Guo , Ricardo Monteiro , Lecheng Ren

Multiloop superstring amplitudes are calculated in the explicit form by the solution of Ward identities. A naive generalization of Belavin-Knizhnik theorem to the superstring is found to be incorrect since the period matrix turns out to be…

High Energy Physics - Theory · Physics 2007-05-23 G. S. Danilov

We study celestial amplitudes in (super) Yang-Mills theory using a parameterisation of the spinor helicity variables where their overall phase is not fixed by the little group action. In this approach the spin constraint $h-\bar{h}=J$ for…

High Energy Physics - Theory · Physics 2021-10-26 Andreas Brandhuber , Graham R. Brown , Joshua Gowdy , Bill Spence , Gabriele Travaglini

We compute the massless five-point amplitude of open superstrings using the non-minimal pure spinor formalism and obtain a simple kinematic factor in pure spinor superspace, which can be viewed as the natural extension of the kinematic…

High Energy Physics - Theory · Physics 2009-04-13 Carlos R. Mafra , Christian Stahn

In this paper the pure spinor formalism is used to obtain a compact expression for the superstring N-point disk amplitude. The color ordered string amplitude is given by a sum over (N-3)! super Yang-Mills subamplitudes multiplied by…

High Energy Physics - Theory · Physics 2011-06-15 Carlos R. Mafra , Oliver Schlotterer , Stephan Stieberger

The full two-loop amplitudes for five massless states in Type~II and Heterotic superstrings are constructed in terms of convergent integrals over the genus-two moduli space of compact Riemann surfaces and integrals of Green functions and…

High Energy Physics - Theory · Physics 2020-07-06 Eric D'Hoker , Carlos R. Mafra , Boris Pioline , Oliver Schlotterer

Using the pure spinor formalism in part I [1] we compute the complete tree-level amplitude of N massless open strings and find a striking simple and compact form in terms of minimal building blocks: the full N-point amplitude is expressed…

High Energy Physics - Theory · Physics 2011-06-15 Carlos R. Mafra , Oliver Schlotterer , Stephan Stieberger

A chiral string can be seen as an ordinary string in a singular gauge for the worldsheet metric and has the ambitwistor string as its tensionless limit. As proposed by Siegel, there is a one-parameter ($\beta$) gauge family interpolating…

High Energy Physics - Theory · Physics 2019-12-20 Renann Lipinski Jusinskas

The contribution from even spin structures to the genus-two amplitude for five massless external NS states in Type II and Heterotic superstrings is evaluated from first principles in the RNS formulation. Using chiral splitting with the help…

High Energy Physics - Theory · Physics 2022-07-26 Eric D'Hoker , Oliver Schlotterer

We use massive spinor helicity formalism to study scattering amplitudes in $\mathcal{N}=2^*$ super-Yang-Mills theory in four dimensions. We compute the amplitudes at an arbitrary point in the Coulomb branch of this theory. We compute…

High Energy Physics - Theory · Physics 2022-08-15 Md. Abhishek , Subramanya Hegde , Dileep P. Jatkar , Arnab Priya Saha

We give the amplitude for $\gamma\gamma \rightarrow \pi^+\pi^-\pi^0$ in leading order chiral perturbation theory. For the case of real photons we calculate the total and differential cross section. Furthermore, we give the dependence of the…

High Energy Physics - Phenomenology · Physics 2009-10-28 J. W. Bos , Y. C. Lin , H. H. Shih

We calculate tree level scattering amplitudes for open strings using the NSR formalism. We present a streamlined symmetry-based and pedagogical approach to the computations, which we first develop by checking two-, three-, and four-point…

High Energy Physics - Theory · Physics 2016-08-22 Katrin Becker , Melanie Becker , Ilarion V. Melnikov , Daniel Robbins , Andrew B. Royston

Using the non-minimal version of the pure spinor formalism, manifestly super-Poincare covariant superstring scattering amplitudes can be computed as in topological string theory without the need of picture-changing operators. The only…

High Energy Physics - Theory · Physics 2009-11-11 Nathan Berkovits , Nikita Nekrasov

Very recently, Grushevsky continued D'Hoker and Phong's program of finding the chiral superstring measure from first principles by constructing modular forms satisfying certain factorization constraints. He has proposed an ansatz in genus 4…

High Energy Physics - Theory · Physics 2011-06-21 Riccardo Salvati Manni

In this paper we continue the program pioneered by D'Hoker and Phong, and recently advanced by Cacciatori, Dalla Piazza, and van Geemen, of finding the chiral superstring measure by constructing modular forms satisfying certain…

High Energy Physics - Theory · Physics 2009-03-20 Samuel Grushevsky

Calculational tools are provided allowing to determine general tree-level scattering amplitudes for processes involving bosons and fermions in heterotic and superstring theories in four space-time dimensions. We compute higher-point…

High Energy Physics - Theory · Physics 2011-10-11 D. Haertl , O. Schlotterer , S. Stieberger

We consider the on-shell amplitudes in N=(1,1) SYM in D=6 dimensions within the spinor helicity and on-shell superspace formalism. This leads to an effective and straightforward technique reducing the calculation to a set of scalar master…

High Energy Physics - Theory · Physics 2015-06-16 L. V. Bork , D. I. Kazakov , D. E. Vlasenko