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S. A. Larin

Publications and source records attributed to S. A. Larin.

At least 19 recordsLinked to original sources
arXiv2024

A Version of Exclusively Perturbative Quantum Field Theory

We suggest a version of renormalizable Quantum Field Theory which does not contain non-perturbative effects. This is otained by the proper use of the boundary conditions in the functional integral of the generating functional of Green functions. It is well known which boundary conditions are applied to the fields of the functional integral to get correct perturbation theory. We propose that these conditions should be used for all fields integrated in the generating functional integral. It is shown that in this case non-perturbative effects are absent. That is we assume that perturbation theory defines the complete generating functional integral. It allows, in particular, to formulate the generating functional integral in a unique way as an exact compact mathematical formula.

physics.gen-ph↗
arXiv2023

A New Solution to the Strong CP Problem

We suggest a new solution to the strong CP problem. The solution is based on the proper use of the boundary conditions for the QCD generating functional integral. We expand the perturbative boundary conditions to both perturbative and nonperturbative fields integrated in the QCD generating functional integral. It allows to nullify the CP odd term in the QCD Lagrangian and thus to solve the strong CP problem. The presently popular solution to the strong CP problem with introducing axions violates the principle of renormalizability of Quantum Field Theory, which is very successful phenomenologically. Our solution obeys the principle of renormalizability of Quantum Field Theory and does not involve new exotic particles like axions.

hep-ph↗
arXiv2022

Renormalizable and unitary Lorentz invariant model of quantum gravity

We analyze the R + R2 model of quantum gravity where terms quadratic in the curvature tensor are added to the General Relativity action. This model was recently proved to be a self-consistent quantum theory of gravitation, being both renormalizable and unitary. The model can be made practically indistinguishable from General Relativity at astrophysical and cosmological scales by the proper choice of parameters.

hep-th↗
arXiv2020

A possibility of CPT violation in the Standard Model

It is shown that there is a possibility of violation of CPT symmetry in the Standard Model which does not contradict to the famous CPT theorem. To check this possibility experimentally it is necessary to increase the precision of measurements of the proton and antiproton mass difference by an order of magnitude

hep-ph↗
arXiv2017

Higher derivative relativistic quantum gravity

Relativistic quantum gravity with the action including terms quadratic in the curvture tensor is analyzed. We derive new expressions for the corresponding Lagrangian and the graviton propagator within dimensional regularization. We argue that the considered model is a good candidate for the fundamental quantum theory of gravitation.

physics.gen-ph↗
arXiv2014

Quantum Chromodynamics with massive gluons

It is shown that the Lagrangian of Quantum Chromodynamics can be modified by the adding gluon masses. On mass-shell renormalizability of the resulting theory is discussed.

hep-ph↗
arXiv2013

Perturbative series and the 1/N expansion for the QED β-function

A comparison of the perturbative series and the 1/N expansion for the QED renormalization group β-function in the Minimal Subtraction scheme is performed. The good agreement between two expansions is found which proves that the MS β-function is under perfect perturbative control.

hep-ph↗
arXiv2013

The singlet contribution to the Bjorken sum rule for polarized deep inelastic scattering

It is shown that the existing four-loop result for the Bjorken polarized sum rule for deep inelastic electron-nucleon scattering obtained within perturbative Quantum Chromodynamics should be supplemented by the calculation of the diagrams of the so called singlet type. We also give an explanation of the interesting coincidence of two different classes of diagrams, one of the non-singlet and one of the singlet type, contributing the $α_s^4$-approximation to the total cross-section of electron-positron annihilation into hadrons.

hep-ph↗
arXiv2005

Renormalizability of the massive Yang-Mills theory

It is shown that the massive Yang-Mills theory is on mass-shell renormalizable. Thus the Standard Model of electroweak interactions can be modified by removing terms with the scalar field from the Lagrangian in the unitary gauge. The resulting electroweak theory without the Higgs particle is on mass-shell renormalizable and unitary.

hep-ph↗
arXiv2004

Determination of the mass of the LambdaLambda dibaryon by the method of QCD sum rules

The method of QCD sum rules is used to calculate the mass of a hypothetical stable dihyperon H with the quantum numbers of two Lambda hyperons, whose existence was predicted by R.L. Jaffe [Phys. Rev. Lett. 31, 195, 617(E) (1977)] in the framework of the MIT quark-bag model. Within the accuracy of the method of QCD sum rules, which in the present case is 20%, the results obtained here agree with those of Jaffe. However, the method of sum rules does not make it possible to determine whether the mass of the dihyperon H lies above or below the Lambda Lambda threshold (i.e., whether H is stable).

hep-ph↗
arXiv1999

The method of expansion of Feynman integrals

The method of expansion of integrals in external parameters is suggested. It is quite universal and works for Feynman integrals both in Euclidean and Minkowski regions of momenta.

hep-ph↗
arXiv1998

Minimal renormalization without ε-expansion: Three-loop amplitude functions of the O(n) symmetric ϕ^4 model in three dimensions below T_c

We present an analytic three-loop calculation for thermodynamic quantities of the O(n) symmetric ϕ^4 theory below T_c within the minimal subtraction scheme at fixed dimension d=3. Goldstone singularities arising at an intermediate stage in the calculation of O(n) symmetric quantities cancel among themselves leaving a finite result in the limit of zero external field. From the free energy we calculate the three-loop terms of the amplitude functions f_phi, F+ and F- of the order parameter and the specific heat above and below T_c, respectively, without using the ε=4-d expansion. A Borel resummation for the case n=2 yields resummed amplitude functions f_phi and F- that are slightly larger than the one-loop results. Accurate knowledge of these functions is needed for testing the renormalization-group prediction of critical-point universality along the λ-line of superfluid He(4). Combining the three-loop result for F- with a recent five-loop calculation of the additive renormalization constant of the specific heat yields excellent agreement between the calculated and measured universal amplitude ratio A+/A- of the specific heat of He(4). In addition we use our result for f_phi to calculate the universal combination R_C of the amplitudes of the order parameter, the susceptibility and the specific heat for n=2 and n=3. Our Borel-resummed three-loop result for R_C is significantly more accurate than the previous result obtained from the ε-expansion up to O(ε^2).

cond-mat.stat-mech↗
arXiv1998

Revised version of "Five-loop additive renormalization in the phi^4 theory and amplitude functions of the minimally renormalized specific heat in three dimensions"

We present an analytic five-loop calculation for the additive renormalization constant A(u,ε) and the associated renormalization-group function B(u) of the specific heat of the O(n) symmetric ϕ^4 theory within the minimal subtraction scheme. We show that this calculation does not require new five-loop integrations but can be performed on the basis of the previous five-loop calculation of the four-point vertex function combined with an appropriate identification of symmetry factors of vacuum diagrams. We also determine the amplitude function F+(u) of the specific heat in three dimensions for n=1,2,3 above T_c and F-(u) for n=1 below T_c up to five-loop order, without using the ε=4-d expansion. Accurate results are obtained from Borel resummations of B(u) for n=1,2,3 and of the amplitude functions for n=1. Previous conjectures regarding the smallness of the resummed higher-order contributions are confirmed. Combining our results for B(u) and F+(u) for n=1,2,3 with those of a recent three-loop calculation of F-(u) for general n in d=3 dimensions we calculate Borel resummed universal amplitude ratios A+/A- for n=1,2,3. Our result for A+/A- = 1.056 +/- 0.004 for n=2 is significantly more accurate than the previous result obtained from the εexpansion up to O(ε^2) and agrees well with the high-precision experimental result A+/A- = 1.054 +/- 0.001 for He(4) near the superfluid transition obtained from a recent experiment in space.

cond-mat.stat-mech↗
arXiv1997

Five-loop additive renormalization in the phi^4 theory and amplitude functions of the minimally renormalized specific heat in three dimensions

We present an analytic five-loop calculation for the additive renormalization constant A(u,epsilon) and the associated renormalization-group function B(u) of the specific heat of the O(n) symmetric phi^4 theory within the minimal subtraction scheme. We show that this calculation does not require new five-loop integrations but can be performed on the basis of the previous five-loop calculation of the four-point vertex function combined with an appropriate identification of symmetry factors of vacuum diagrams. We also determine the amplitude functions of the specific heat in three dimensions for n=1,2,3 above T_c and for n=1 below T_c up to five-loop order. Accurate results are obtained from Borel resummations of B(u) for n=1,2,3 and of the amplitude functions for n=1. Previous conjectures regarding the smallness of the resummed higher-order contributions are confirmed. Borel resummed universal amplitude ratios A^+/A^- and a_c^+/a_c^- are calculated for n=1.

cond-mat.stat-mech↗
arXiv1997

The Large Quark Mass Expansion of Gamma (Z^0 -> hadrons) and Gamma(tau^- -> nu_tau + hadrons) in the Order alpha_s^3

We present the analytical $α_{s}^3$ correction to the $Z^{0}$ decay rate into hadrons. We calculate this correction up to (and including) terms of the order $(m_Z^2/m_{top}^2)^3$ in the large top quark mass expansion. We rely on the technique of the large mass expansion of individual Feynman diagrams and treat its application in detail. We convert the obtained results of six flavour QCD to the results in the effective theory with five active flavours, checking the decoupling relation of the QCD coupling constant. We also derive the large charm quark mass expansion of the semihadronic $τ$ lepton decay rate in the $α_{s}^3$ approximation.

hep-ph↗