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Related papers: One Loop Tadpole in Heterotic String Field Theory

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We investigate the quantum structure of Witten's cubic open bosonic string field theory by computing the one-loop contribution to the open string tadpole using both oscillator and conformal field theory methods. We find divergences and a…

High Energy Physics - Theory · Physics 2014-11-18 Ian Ellwood , Jessie Shelton , Washington Taylor

We construct $\mathbb{Z}_N$ orbifolds of the ten-dimensional heterotic string theories appropriate for implementing the stringy replica method for the calculation of quantum entanglement entropy. A novel feature for the heterotic string is…

High Energy Physics - Theory · Physics 2024-12-06 Atish Dabholkar , Upamanyu Moitra

Recently, it has been shown that the holomorphic anomaly of unitarity cuts can be used as a tool in determining the one-loop amplitudes in N=4 super Yang-Mills theory. It is interesting to examine whether this method can be applied to more…

High Energy Physics - Theory · Physics 2010-11-15 Steven J. Bidder , N. E. J. Bjerrum-Bohr , Lance J. Dixon , David C. Dunbar

In this paper we analyze the problem of tadpole cancellation in open topological strings. We prove that the inclusion of unorientable worldsheet diagrams guarantees a consistent decoupling of A and B model for open superstring amplitudes at…

High Energy Physics - Theory · Physics 2009-07-30 Giulio Bonelli , Andrea Prudenziati , Alessandro Tanzini , Jie Yang

Calculation of amplitudes in perturbative quantum field theory involve large loop integrals. The complexity of those integrals, in combination with the large number of Feynman diagrams, make the calculations very difficult. Reduction…

High Energy Physics - Phenomenology · Physics 2015-06-05 Ronald H. P. Kleiss , Ioannis Malamos , Costas G. Papadopoulos , Rob Verheyen

We bootstrap one-loop string corrections to the four-point function of half-BPS operators in a 4d $\mathcal{N}=2$ SCFT with flavour group $SO(8)$, dual to gluon scattering at genus one on AdS$_5\times$S$^3$. We identify an 8-dimensional…

High Energy Physics - Theory · Physics 2024-01-10 Hynek Paul , Michele Santagata

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

A method to define and calculate one-loop amplitudes with an off-shell space-like, or $k_T$-dependent, gluon is presented. It introduces a practical regularization to deal with the divergencies that appear due to linear denominators, and…

High Energy Physics - Phenomenology · Physics 2022-02-01 A. van Hameren

Exact Superstring solutions are constructed moving in 4-D space-time with positive curvature and non-trivial dilaton and antisymmetric tensor fields. The full spectrum of string excitations is derived as a function of moduli fields $T^{i}$…

High Energy Physics - Theory · Physics 2016-09-06 Elias Kiritsis , Costas Kounnas

We study the high-energy limit of $2 \to 2$ one-loop string amplitudes at fixed momentum transfer. For the closed string, the high-energy behaviour of the amplitudes can be determined from Regge theory just like in field theory, as was…

High Energy Physics - Theory · Physics 2025-08-27 Pinaki Banerjee , Lorenz Eberhardt , Sebastian Mizera

We review the recently developed bootstrap method for the computation of high-multiplicity QCD amplitudes at one loop. We illustrate the general algorithm step by step with a six-point example. The method combines (generalized) unitarity…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger

We describe the recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD. The method combines the unitarity method with loop-level on-shell recursion. The unitarity method is used to…

High Energy Physics - Phenomenology · Physics 2008-11-26 Carola F. Berger , Zvi Bern , Lance J. Dixon , Darren Forde , David A. Kosower

Open topological string amplitudes on compact Calabi-Yau threefolds are shown to satisfy an extension of the holomorphic anomaly equation of Bershadsky, Cecotti, Ooguri and Vafa. The total topological charge of the D-brane configuration…

High Energy Physics - Theory · Physics 2010-04-05 Johannes Walcher

We consider the algebraic couplings in the tree level effective action of the heterotic string. We show how these couplings can be computed from closed string field theory. When the light fields we are interested in are charged under an…

High Energy Physics - Theory · Physics 2020-03-18 Harold Erbin , Carlo Maccaferri , Jakub Vošmera

Noncommutative \phi^3 field theory in six dimensions exhibits the logarithmic UV/IR mixing at the two-loop order. We show that open string theory in the presence of constant background NS-NS two-form field yields the same amplitude upon…

High Energy Physics - Theory · Physics 2008-11-26 Youngjai Kiem , Sangmin Lee , Jaemo Park

We present a completely numerical method of calculating one-loop amplitudes. Our approach is built upon two different existing methods: the contour deformation and the extrapolation methods. Taking the best features of each of them, we…

High Energy Physics - Phenomenology · Physics 2017-02-01 Goran Duplancic , Bruno Klajn

Field redefinitions at string 1-loop order are often required by supersymmetry, for instance in order to make the K\"ahler structure of the scalar kinetic terms manifest. We derive the general structure of the field redefinitions and the…

High Energy Physics - Theory · Physics 2018-08-29 Michael Haack , Jin U Kang

The low-energy expansion of one-loop amplitudes in type II string theory generates a series of world-sheet integrals whose integrands can be represented by world-sheet Feynman diagrams. These integrands are modular invariant and…

High Energy Physics - Theory · Physics 2017-10-25 Axel Kleinschmidt , Valentin Verschinin

We present an analytic technique for evaluating single cuts for one-loop integrands, where exactly one propagator is taken to be on shell. Our method extends the double-cut integration formalism of one-loop amplitudes to the single-cut…

High Energy Physics - Theory · Physics 2011-02-03 Ruth Britto , Edoardo Mirabella

In this paper we compute 1-loop corrections to the bispectrum in the decoupling limit of the Effective Field Theory of Inflation (EFToI). We regulate the divergences by employing dimensional regularization and work in $d=3+\delta$…

High Energy Physics - Theory · Physics 2024-10-11 Supritha Bhowmick , Diptimoy Ghosh , Farman Ullah