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We use dimensional recurrence relations and analyticity to calculate four-loop propagator-type master integrals in the heavy-quark effective theory. Compared to previous applications of the DRA method, we apply a new technique of fixing homogeneous solutions from pole parts of integrals evaluated in different rational space-time dimension points. The latter were calculated from the integration-by-parts reduction of finite integrals in shifted space-time dimension and/or with increased propagators powers. We provide results for epsilon expansions of master integrals near $d = 4$ and $d = 3$ using constructed alternative sets of integrals with expansion coefficients having conjectural uniform transcendental weight.

We consider the Sudakov form factor in N=4 SYM in the off-shell kinematical regime, which can be achieved by considering the theory on its Coulomb branch. We demonstrate that up two three loops both the infrared-divergent as well as the finite terms do exponentiate, with the coefficient accompanying $\log^2(m^2)$ determined by the octagon anomalous dimension $\Gamma_{oct}$. This behaviour is in strike contrast to previous conjectural accounts in the literature. Together with the finite terms we observe that up to three loops the logarithm of the Sudakov form factor is identical to twice the logarithm of the null octagon $\mathbb{O}_0$, which was recently introduced within the context of integrability-based approaches to four point correlation functions with infinitely-large R-charges. The null octagon $\mathbb{O}_0$ is known in a closed form for all values of the 't Hooft coupling constant and kinematical parameters. We conjecture that the relation between $\mathbb{O}_0$ and the off-shell Sudakov form factor will hold to all loop orders., Comment: 5 pages, 2 figures

We calculate the small angle expansion of the four-loop QCD cusp anomalous dimension. As a byproduct of our calculation, we also obtain the four-loop anomalous dimension of the heavy-quark field in HQET. The validity of the calculational setup is cross-checked by the independent calculation of the four-loop QCD beta-function from heavy-quark-gluon vertex renormalization in HQET. We check the obtained results for the cusp anomalous dimension and heavy-quark field anomalous dimension against available analytical and numerical results. Finally, we find that the maximal transcendentality contribution to the QCD Bremsstrahlung function coincides, up to a factor 3/2, with the Bremsstrahlung function in N = 4 supersymmetric Yang-Mills theory, at least, through 4 loops., Comment: ancillary files with results

We calculate the leading Coulomb correction to the energy loss in the electron-nucleus Bremsstrahlung for arbitrary energy of the incoming particle. This correction determines the charge asymmetry, i.e., the difference of electron and positron energy loss. The result is presented in terms of the classical polylogarithms $\mathrm{Li}_2$ and $\mathrm{Li}_3$. We use modern multiloop methods based on the IBP reduction and on the differential equations for master integrals. We provide both the threshold and the high-energy asymptotics of the found asymmetry and compare them with the available results., Comment: 14 pages

We calculate the three- and four-loop corrections to the massless fermion propagator in three-dimensional quenched Quantum Electrodynamics with four-component fermions. The three-loop correction is finite and gauge invariant but the four-loop one has singularities except in the Feynman gauge where it is also finite. Our results explicitly show that, up to four loops, gauge-dependent terms are completely determined by lower order ones in agreement with the Landau-Khalatnikov-Fradkin transformation., Comment: 11+4 pages

We consider the scalar sector of a general renormalizable theory and evaluate the effective potential through three loops analytically. We encounter three-loop vacuum bubble diagrams with up to two masses and six lines, which we solve using differential equations transformed into the favorable $\epsilon$ form of dimensional regularization. The master integrals of the canonical basis thus obtained are expressed in terms of cyclotomic polylogarithms up to weight four. We also introduce an algorithm for the numerical evaluation of cyclotomic polylogarithms with multiple-precision arithmetic, which is implemented in the Mathematica package cyclogpl.m supplied here., Comment: 14 pages, 2 figures, 9 ancillary files, minor changes, matches journal version

We evaluate the three-loop massive vacuum bubble diagrams in terms of polylogarithms up to weight six. We also construct the basis of irrational constants being harmonic polylgarithms of arguments $e^{k i \pi/3}$., Comment: 26 pages, 4 ancillary files, v3: version published in JHEP: minor additions, file with results for massive three-loop form-factor integrals added

We consider electroweak corrections to the relation between the running $\overline{\mathrm{MS}}$ mass $m_b$ of the $b$ quark in the five-flavor QCD$\times$QED effective theory and its counterpart in the Standard Model (SM). As a bridge between the two parameters, we use the pole mass $M_b$ of the $b$ quark, which can be calculated in both models. The running mass is not a fundamental parameter of the SM Lagrangian, but the product of the running Yukawa coupling $y_b$ and the Higgs vacuum expectation value. Since there exist different prescriptions to define the latter, the relations considered in the paper involve a certain amount of freedom. All the definitions can be related to each other in perturbation theory. Nevertheless, we argue in favor of a certain gauge-independent prescription and provide a relation which can be directly used to deduce the value of the Yukawa coupling of the $b$ quark at the electroweak scale from its effective QCD running mass. This approach allows one to resum large logarithms $\ln(m_b/M_t)$ systematically. Numerical analysis shows that, indeed, the corrections to the proposed relation are much smaller than those between $y_b$ and $M_b$., Comment: 19 pages, 4 figures, misprints corrected (thanks to S. Martin), results not affected

In the talk the leading four-loop contribution to the beta-function of the strong coupling in the SM is discussed. Some details of calculation techniques are provided. Special attention is paid to the ambiguity due to utilized $\gamma_5$ treatment and a particular prescription with anticommuting $\gamma_5$ is advocated. As a by-product of our computation the four-loop beta-function in QCD with "gluino" is also obtained., Comment: 6 pages, 2 figures, submitted to Proceedings of 19th International Seminar on High Energy Physics "QUARKS-2016", Pushkin, Russia, May-June, 2016

We present the C++ program library mr that allows us to reliably calculate the values of the running parameters in the Standard Model at high energy scales. The initial conditions are obtained by relating the running parameters in the $\overline{\mathrm{MS}}$ renormalization scheme to observables at lower energies with full two-loop precision. The evolution is then performed in accordance with the renormalization group equations with full three-loop precision. Pure QCD corrections to the matching and running are included through four loops. We also provide a Mathematica interface for this program library., Comment: 29 pages, minor changes, references added, matches journal version, Highlighted Article in Comput. Phys. Commun., featured by Abigail Beall as "A time machine to explore the universe" (http://www.journals.elsevier.com/computer-physics-communications/highlighted-articles/a-time-machine-to-explore-the-universe)

In this letter we present our results for the four-loop beta-function of the strong coupling in the Standard Model of fundamental interactions. We take top-Yukawa and self-Higgs interactions into account, but neglect electroweak gauge couplings., Comment: 9 pages, 2 figures. Final result changed due to different Gamma 5 treatment

We perform a manifestly gauge-independent analysis of the vacuum stability in the Standard Model (SM) including two-loop matching, three-loop renormalization group evolution, and pure QCD corrections through four loops. All these ingredients are exact, except that light-fermion masses are neglected. We in turn apply the criterion of nullifying the $\overline{\mathrm{MS}}$ Higgs self-coupling and its beta function and a recently proposed consistent method for determining the true minimum of the effective Higgs potential that also avoids gauge dependence. Exploiting our knowledge of the Higgs-boson mass, we derive an upper bound on the pole mass of the top quark by requiring that the SM be stable all the way up to the Planck mass scale and conservatively estimate the theoretical uncertainty. This bound is compatible with Monte Carlo mass quoted by the Particle Data Group at the $1.3\sigma$ level., Comment: 5 pages, 2 figures, matches journal version, PRL Editors' Suggestion, featured by Alexander Kusenko as Viewpoint: Are We on the Brink of the Higgs Abyss? in Physics (http://physics.aps.org/articles/v8/108)

We study the relationships between the basic parameters of the on-shell renormalization scheme and their counterparts in the $\overline{\mathrm{MS}}$ scheme at full order ${\cal O}(\alpha^2)$ in the Standard Model. These enter as threshold corrections the renormalization group analyses underlying, e.g., the investigation of the vacuum stability. To ensure the gauge invariance of the parameters, in particular of the $\overline{\mathrm{MS}}$ masses, we work in $R_\xi$ gauge and systematically include tadpole contributions. We also consider the gaugeless-limit approximation and compare it with the full two-loop electroweak calculation., Comment: 33 pages, 1 figure, matches journal publication

We present the extension of our previous results for three-loop Yukawa coupling beta-functions to the case of complex Yukawa matrices describing the flavour structure of the SM. The calculation is carried out in the context of unbroken phase of the SM with the help of the MINCER program in a general linear gauge and cross-checked by means of MATAD/BAMBA codes. In addition, ambiguities in Yukawa matrix beta-functions are studied., Comment: 9 pages, references added, version accepted by PLB

Three-loop renormalization group equations for the Higgs self-coupling and Higgs mass parameter are recalculated in the case of complex Yukawa matrices, which encompass general flavour structure of the Standard Model. In addition, the anomalous dimensions both for the quantum Higgs field and its vacuum expectation value are presented in the $\overline{MS}$-scheme. A numerical study of the latter quantities is carried out for a certain set of initial parameters., Comment: 14 pages, 2 figures, report numbers added, figures redrawn

In this talk the methods and computer tools which were used in our recent calculation of the three-loop Standard Model renormalization group coefficients are discussed. A brief review of the techniques based on special features of dimensional regularization and minimal subtraction schemes is given. Our treatment of gamma5 is presented in some details. In addition, for a reasonable set of initial parameters the numerical estimates of the obtained three-loop contributions are presented., Comment: 8 pages, 5 figures, Talk presented at ACAT 2013. To be submitted to the proceedings of ACAT 2013

We present the results for three-loop beta-function for the Higgs self-coupling calculated within the unbroken phase of the Standard Model. We also provide the expression for three-loop beta-function of the Higgs mass parameter, which is obtained as a by-product of our main calculation. Our results coincide with that of recent paper arXiv:1303.2890. In addition, the expression for the Higgs field anomalous dimension is given., Comment: 15 pages, 1 figure, Mathematica outputs attached. Ancillary files rearranged. arXiv admin note: text overlap with arXiv:1212.6829

We present the results for three-loop beta-functions for Yukawa couplings of heavy Standard Model fermions calculated within the unbroken phase of the model. The calculation is carried out with the help of the MINCER program in a general linear gauge, and the final result is independent of the gauge-fixing parameters. In order to calculate three-point functions, we made use of infrared rearrangement (IRR) trick. Due to the chiral structure of the SM a careful treatment of loops with fermions is required to perform the calculation. It turns out that gauge anomaly cancellation in the SM allows us to obtain the result by means of the semi-naive treatment of gamma5., Comment: 7 pages, 1 figure, discussion about gamma5 extended, numerical estimates changed according to new ancillary files with correct results

We present the results for three-loop gauge field anomalous dimensions in the SM calculated in the background field gauge within the unbroken phase of the model. The results are valid for the general background field gauge parameterized by three independent parameters. Both quantum and background fields are considered. The former are used to find three-loop anomalous dimensions for the gauge-fixing parameters, and the latter allow one to obtain the three-loop SM gauge beta-functions. Independence of beta-functions of gauge-fixing parameters serves as a validity check of our final results., Comment: 23 pages, self-coupling normalization fixed, anc files corrected accordingly

We present the result of the three loop anomalous dimension of non-singlet transversity operator in QCD for the Mellin moment N=16. The obtained result coincides with the prediction from arXiv:1203.1022 and can serve as a confirmation of the correctness of the general expression for three loop anomalous dimension of non-singlet transversity operator in QCD for the arbitrary Mellin moment., Comment: 7 pages, 1 figure, minor changes in the text

The LHC data on the forward heavy flavour hadron production can be a new unique source for estimation of intrinsic charm and bottom contributions to the proton. For example, we analyze the forward heavy baryon production, namely $\Lambda_b$-baryon, within the soft QCD quark gluon string model and present the predictions for observables which could be measured at the LHC. We also present some predictions for the $D$-meson production in $pp$ collisions made within the perturbative QCD including the intrinsic charm in the proton that can be verified at the LHC., Comment: 14 pages, 10 figures