Nonlinear Phenomena in Complex Systems, 2021, Vol.25, No.3, pp.297

NONLINEAR PHENOMENA IN COMPLEX SYSTEMS
An Interdisciplinary Journal

2022, Vol.25, No.3, pp.297 - 305

Nonperturbative Corrections to Adler Function and Hypothesis of Vacuum Dominance

Marina Kozhevnikova, Armen Oganesian, Oleg Teryaev, and Olga Solovtsova

We check the range of values of four-quark condensate, relying on the processing of experimental data on e⁺e⁻ annihilation into even number of pions (BaBar, CMD-2, OLYA) and extracting from them the values of the nonperturbative corrections. According to the hypothesis of vacuum dominance, the vacuum average of the four-quark condensate is expressed in terms of quark condensate while only vacuum intermediate states contribution is taken into account. However, assuming a possible non-zero effect of non-vacuum intermediate states, we check its influence on the four-quark condensate, or coefficient C₆ in operator product expansion. Moreover, we explore how other nonperturbative corrections, C₂ (operator with dimension 2), and C₄ (which includes gluon condensate), are changed when assuming this effect. It is shown that values of four-quark condensate, or coefficient C₆, can vary not more than 15-20%. Other parameters (C₂ and C₄) take values close to the currently available ones.

Key words: quantum chromodynamics, OPE, sum rules, confinement

DOI: https://doi.org/10.33581/1561-4085-2022-25-3-297-305

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