10,487 research outputs found

    Twist-three at five loops, Bethe Ansatz and wrapping

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    We present a formula for the five-loop anomalous dimension of N=4 SYM twist-three operators in the sl(2) sector. We obtain its asymptotic part from the Bethe Ansatz and finite volume corrections from the generalized Luescher formalism, considering scattering processes of spin chain magnons with virtual particles that travel along the cylinder. The complete result respects the expected large spin scaling properties and passes non-trivial tests including reciprocity constraints. We analyze the pole structure and find agreement with a conjectured resummation formula. In analogy with the twist-two anomalous dimension at four-loops, wrapping effects are of order log^2 M/M^2 for large values of the spin.Comment: 19 page

    Four loop reciprocity of twist two operators in N=4 SYM

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    The four loop universal anomalous dimension of twist-2 operators in N=4 SYM has been recently conjectured. In this paper, we prove that it obeys a generalized Gribov-Lipatov reciprocity, previously known to hold at the three loop level.Comment: 15 pages, v3: Appendix A.3 added, main body shortened, version accepted in JHE

    New Results on Massive 3-Loop Wilson Coefficients in Deep-Inelastic Scattering

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    We present recent results on newly calculated 2- and 3-loop contributions to the heavy quark parts of the structure functions in deep-inelastic scattering due to charm and bottom.Comment: Contribution to the Proc. of Loops and Legs 2016, PoS, in prin

    Six-loop anomalous dimension of twist-two operators in planar N=4 SYM theory

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    We compute the general form of the six-loop anomalous dimension of twist-two operators with arbitrary spin in planar N=4 SYM theory. First we find the contribution from the asymptotic Bethe ansatz. Then we reconstruct the wrapping terms from the first 35 even spin values of the full six-loop anomalous dimension computed using the quantum spectral curve approach. The obtained anomalous dimension satisfies all known constraints coming from the BFKL equation, the generalised double-logarithmic equation, and the small spin expansion.Comment: 33 pages, 4 ancillary files, minor change

    Anomalous dimensions at twist-3 in the sl(2) sector of N=4 SYM

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    We consider twist-3 operators in the sl(2) sector of N=4 SYM built out of three scalar fields with derivatives. We extract from the Bethe Ansatz equations of this sector the exact lowest anomalous dimension gamma(s) of scaling fields for several values of the operator spin s. We propose compact closed expressions for the spin dependence of gamma(s) up to the four loop level and show that they obey a simple new twist-3 transcendentality principle. As a check, we reproduce the four loop universal cusp anomalous dimension governing the logarithmic large spin limit of gamma(s).Comment: 26 pages, JHEP styl

    Iterated Binomial Sums and their Associated Iterated Integrals

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    We consider finite iterated generalized harmonic sums weighted by the binomial (2kk)\binom{2k}{k} in numerators and denominators. A large class of these functions emerges in the calculation of massive Feynman diagrams with local operator insertions starting at 3-loop order in the coupling constant and extends the classes of the nested harmonic, generalized harmonic and cyclotomic sums. The binomially weighted sums are associated by the Mellin transform to iterated integrals over square-root valued alphabets. The values of the sums for N→∞N \rightarrow \infty and the iterated integrals at x=1x=1 lead to new constants, extending the set of special numbers given by the multiple zeta values, the cyclotomic zeta values and special constants which emerge in the limit N→∞N \rightarrow \infty of generalized harmonic sums. We develop algorithms to obtain the Mellin representations of these sums in a systematic way. They are of importance for the derivation of the asymptotic expansion of these sums and their analytic continuation to N∈CN \in \mathbb{C}. The associated convolution relations are derived for real parameters and can therefore be used in a wider context, as e.g. for multi-scale processes. We also derive algorithms to transform iterated integrals over root-valued alphabets into binomial sums. Using generating functions we study a few aspects of infinite (inverse) binomial sums.Comment: 62 pages Latex, 1 style fil

    Proof of a modular relation between 1-, 2- and 3-loop Feynman diagrams on a torus

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    The coefficients of the higher-derivative terms in the low energy expansion of genus-one graviton Type II superstring scattering amplitudes are determined by integrating sums of non-holomorphic modular functions over the complex structure modulus of a torus. In the case of the four-graviton amplitude, each of these modular functions is a multiple sum associated with a Feynman diagram for a free massless scalar field on the torus. The lines in each diagram join pairs of vertex insertion points and the number of lines defines its weight ww, which corresponds to its order in the low energy expansion. Previous results concerning the low energy expansion of the genus-one four-graviton amplitude led to a number of conjectured relations between modular functions of a given ww, but different numbers of loops ≀w−1\le w-1. In this paper we shall prove the simplest of these conjectured relations, namely the one that arises at weight w=4w=4 and expresses the three-loop modular function D4D_4 in terms of modular functions with one and two loops. As a byproduct, we prove three intriguing new holomorphic modular identities.Comment: 38 pages, 9 figures, in version 2: Appendix D added and corrections made in section
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