Spin-2 form factors at three loop in QCD

Ahmed, Taushif; Das, Goutam; Mathews, Prakash; Rana, N. C.; Ravindran, V.

doi:10.1007/jhep12(2015)084

Cited by 20 publications

(22 citation statements)

References 90 publications

(136 reference statements)

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“…In this section, after a brief discussion on how we have performed the computation, we present the unrenormalized form factorsF I,i,(n) and the anomalous dimensions γ IJ up to three loop level. We closely follow the steps used in the derivation of three loop unrenormalized form factors of scalar and vector form factors [23,24], see also [26,27,60]. The relevant Feynman diagrams are generated using QGRAF [61].…”

Section: Computation and Resultsmentioning

confidence: 99%

Three loop form factors of a massive spin-2 particle with nonuniversal coupling

et al. 2017

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We investigate the interaction of spin-2 fields with those of the Standard Model in a model independent framework. We have considered interactions where the spin-2 fields couple to two sets of gauge invariant tensorial operators that are not conserved unlike the energy momentum tensor with different coupling strengths. Such interactions not only change the ultraviolet behaviour of the couplings but also expand the scope of the searches of spin-2 particles at the colliders. We present all the relevant renormalisation constants up to three loop level in QCD and also the form factors that contribute to potential observables. This sets the ground to investigate the phenomenological consequences of these interactions with spin-2 fields through more than one tensorial operator.

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Section: Computation and Resultsmentioning

confidence: 99%

Three loop form factors of a massive spin-2 particle with nonuniversal coupling

et al. 2017

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“…The calculation of the FFs follows closely the steps used in the derivation of the 3-loop spin-2 and pseudo-scalar FFs in QCD [17,18]. In contrast to the most popular method of on-shell unitarity for computing the scattering amplitudes in N = 4 SYM, we use the conventional Feynman diagrammatic approach, which carries its own advantages in light of following the regularization scheme, to accomplish the job.…”

Section: Calculation Of the Form Factorsmentioning

confidence: 99%

Konishi form factor at three loops in N=4 supersymmetric Yang-Mills theory

Ahmed¹,

Banerjee²,

Dhani³

et al. 2017

Phys. Rev. D

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We present the first results on the third order corrections to on-shell form factor (FF) of the Konishi operator in N = 4 supersymmetric Yang-Mills theory using Feynman diagrammatic approach in modified dimensional reduction (DR) scheme. We show that it satisfies KG equation in DR scheme while the result obtained in four dimensional helicity (FDH) scheme needs to be suitably modified not only to satisfy the KG equation but also to get the correct ultraviolet (UV) anomalous dimensions. We find that the cusp, soft and collinear anomalous dimensions obtained to third order are same as those of the FF of the half-BPS operator confirming the universality of the infrared (IR) structures of on-shell form factors. In addition, the highest transcendental terms of the FF of Konishi operator are identical to those of half-BPS operator indicating the probable existence of deeper structure of the on-shell FF. We also confirm the UV anomalous dimensions of Konishi operator up to third order providing a consistency check on the both UV and universal IR structures in N = 4. PACS numbers: 12.38BxThe ability to accomplish the challenging job of calculating quantities is of fundamental importance in any potential mathematical theory. In quantum field theory (QFT), this manifests itself in the quest for computing the multi-loop and multi-leg scattering amplitudes under the glorious framework of age-old perturbation theory. The fundamental quantities to be calculated in any gauge theory are the scattering amplitudes or the correlation functions. Recently, there have been surge of interest to study form factors (FFs) as they connect fully on-shell amplitudes and correlation functions. The FFs are a set of quantities which are constructed out of the scattering amplitudes involving on-shell states consisting of elementary fields and an off-shell state described through a composite operator. These are operator matrix elements of the form p σ1 1 , · · · , p σ l l |O|0 where, O represents a gauge invariant composite operator which generates a multiparticle on-shell state |p σ1 1 , · · · , p σ l l upon operating on the vacuum of the theory. p i are the momenta and σ i encapsulate all the other quantum numbers of the particles. More precisely, FFs are the amplitudes of the processes where classical current or field, coupled through gauge invariant composite operator O, produces some quantum state. Studying these quantities not only help to understand the underlying ultraviolet and infrared structures of the theory, but also enable us to calculate the anomalous dimensions of the associated composite operator.The Sudakov FFs (l = 2) in N = 4 maximally supersymmetric Yang-Mills (SYM) theory [1, 2] were initially considered by van Neerven in [3], almost three decades back, where a half-BPS operator belonging to the stressenergy supermultiplet, that contains the conserved currents of N = 4 SYM, was investigated to 2-loop order:Very recently, this was extended to 3-loop in [4]. We will represent scalar and pseudo-scalar fields by φ a m and χ a m ...

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“…The computation of S Λ,(i) a for a = g, q; Λ = G, J, GJ, JG, i = 0, 1, 2 closely follows the steps used in [67][68][69][70][71][72][73][74]. We briefly describe the main steps involved.…”

Section: Matrix Elementsmentioning

confidence: 99%

Two loop QCD corrections for the process pseudo-scalar Higgs → 3 partons

Banerjee

Dhani

Ravindran

2017

J. High Energ. Phys.

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We present virtual contributions up to two loop level in perturbative Quantum Chromodynamic (QCD) to the decay of pseudo-scalar Higgs boson (A) to three gluons (g) and also to quark (q), anti-quark (q) and a gluon. With appropriate crossing, they are well suited for predicting the differential distribution of A in association with a jet in hadron colliders up to next-to-next-to-leading order (NNLO) in strong coupling constant and also for the subsequent decay of A to hadrons. We use effective field theory approach to integrate out the top quarks in the heavy top limit. The resulting theory involves two pseudo-scalar composite operators describing the interaction of A with gluons as well as with quark and anti-quark. We perform our computation in dimensional regularisation and use minimal subtraction (M S) scheme to renormalise strong coupling constant as well as the composite operators. The ultraviolet (UV) finite amplitudes contain infrared (IR) divergences that are found to be in agreement with the predictions by Catani. For both the amplitudes namely A → ggg and A → qqg, the leading transcendental terms at one and two loops are found to be identical to those in a three point form factor (FF) of the half-BPS operator in N = 4 Supersymmetric Yang Mills (SYM) theory when the QCD color factors are adjusted in a specific way. We present our results in terms of harmonic polylogs well suited for further numerical study.

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Spin-2 form factors at three loop in QCD

Cited by 20 publications

References 90 publications

Three loop form factors of a massive spin-2 particle with nonuniversal coupling

Three loop form factors of a massive spin-2 particle with nonuniversal coupling

Konishi form factor at three loops in N=4 supersymmetric Yang-Mills theory

Two loop QCD corrections for the process pseudo-scalar Higgs → 3 partons

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