arXiv subjects

Oleg Teryaev

Publications and source records attributed to Oleg Teryaev.

At least 37 records · Page 2Linked to original sources

arXiv2017

Anomalous current from covariant Wigner functions

We consider accelerated and rotating media of weakly interacting fermions in local thermodynamic equilibrium. Kinetic properties of this media are described by covariant Wigner function calculated on the basis of relativistic distribution function of particles with spin. We obtain the formulae for axial current beyond the approximation of smallness of thermal vorticity tensor and chemical potential and calculate its divergence. In the massless limit higher order terms in vorticity and chemical potential compensate each other with only the low-order contributions surviving. It is shown, that axial current gets a topological component along the 4-acceleration vector. The similarity between different approaches to baryon polarisation is established.

hep-th↗

arXiv2017

Mirror QCD and Cosmological Constant

An analog of Quantum Chromo Dynamics (QCD) sector known as mirror QCD (mQCD) can affect the cosmological evolution due to a non-trivial contribution to the Cosmological Constant analogous to that induced by the ground state in non-perturbative QCD. In this work, we explore a plausible hypothesis for trace anomalies cancellation between the usual QCD and mQCD. Such an anomaly cancellation between the two gauge theories, if exists in Nature, would lead to a suppression or even elimination of their contributions to the Cosmological Constant. The trace anomaly compensation condition and the form of the non-perturbative mQCD coupling constant in the infrared limit have been proposed by analysing a partial non-perturbative solution of the Einstein--Yang-Mills equations of motion.

hep-ph↗

arXiv2016

Search for short strings in~$e^+e^-$-annihilation

In this work the behavior of power corrections to Adler finction in operator product expansion (OPE) is studied, in particular the possible contribution of operator of dimension 2. The OPE terms of dimension 4 and 6 are taken into account. Various experimental data on reactions of $e^+e^-$-annihilation to pion channels ($π^+π^-$, $2π^+2π^-$, $π^+π^-2π^0$, $3π^+3π^-$, $2π^+2π^-2π^0$) are used. The high-precision fits of the experimental data are obtained and used. The method based on Borel transform of Adler function is applied. It is shown that the contribution of operator of dimension 2 is negative being compatible to zero at three standard deviations level. The strong (anti)corellation between short string and local gluon condensate is found.

hep-ph↗

arXiv2016

Interpretation of Angular Distributions of $Z$-boson Production at Colliders

High precision data of dilepton angular distributions in $γ^*/Z$ production were reported recently by the CMS Collaboration covering a broad range of the dilepton transverse momentum, $q_T$, up to $\sim 300$ GeV. Pronounced $q_T$ dependencies of the $λ$ and $ν$ parameters, characterizing the $\cos^2θ$ and $\cos 2ϕ$ angular distributions, were found. Violation of the Lam-Tung relation was also clearly observed. We show that the $q_T$ dependence of $λ$ allows a determination of the relative contributions of the $q \bar q$ annihilation versus the $qG$ Compton process. The violation of the Lam-Tung relation is attributed to the presence of a non-zero component of the $q - \bar q$ axis in the direction normal to the "hadron plane" formed by the colliding hadrons. The magnitude of the violation of the Lam-Tung relation is shown to reflect the amount of this `non-coplanarity". The observed $q_T$ dependencies of $λ$ and $ν$ from the CMS and the earlier CDF data can be well described using this approach.

hep-ph↗

arXiv2013

Axial anomaly and vector meson dominance model

The dispersive representation of axial anomaly leads to the anomaly sum rules (ASRs), exact nonperturbative relations in QCD. The analytical continuation of the ASRs to the time-like region is performed. The transition form factors of $π^0$, $η$ and $η'$ mesons in this region are calculated. A good agreement with the available experimental data is found. Based on the ASRs, we have provided the foundations for the vector meson dominance model in these processes.

hep-ph↗

arXiv2013

Analyticity and higher twists

The representation for infinite sum of higher twists (HT) tower in DIS implied by analyticity of virtual Compton amplitude is suggested. Its simplest realization allows to describe the Bjorken sum rule at all momentum transfers. It is stressed that TMDs accommodate the infinite tower of HT similar to non-local vacuum condensates for the case of vacuum matrix element. The D-term in hadronic GPDs bears some similarity to vacuum cosmological constant. The negative sign of D-term may be understood as a similarity between inflation and annihilation via the graviton exchange.

hep-ph↗

arXiv2013

Transition form factors of $π^0$, $η$ and $η'$ mesons: What can be learned from anomaly sum rule?

We have studied the applications of the anomaly sum rule to the transition form factors of light pseudoscalar mesons: $π^0$, $η$ and $η'$. This nonperturbative QCD approach can be used even if the QCD factorization is broken. The possibility of small non-OPE corrections to the spectral density in view of the recent BaBar and Belle data is explored. The accuracy of the applied method and the role of the quark mass contributions are discussed.

hep-ph↗

arXiv2013

Transition Form Factors and Mixing of Pseudoscalar Mesons from Anomaly Sum Rule

Transition form factors of pi^0, eta, eta' mesons are investigated by means of the anomaly sum rule -- an exact nonperturbative relation which follows from the dispersive representation of the axial anomaly. Considering the problem of contributions of operators originated from a non-(local) operator product expansion, we found that they are required by the available set of experimental data, including the most recent data from the Belle Collaboration (which, if taken alone, can be described without such contributions, although are compatible with them). In this approach we analyzed the experimental data on eta and eta' meson transition form factors and obtained the constraints on the decay constants and mixing parameters.

hep-ph↗

arXiv2013

Axial Anomaly and Light Cone Distributions

Axial anomaly leads to exact sum rules for transition form factors providing the important constraints to respective distribution amplitudes. This rigorous NPQCD approach is valid even if QCD factorization is broken. The status of possible small non-OPE corrections to continuum in comparison to BABAR and BELLE data is discussed.

hep-ph↗

arXiv2013

Helicity separation in Heavy-Ion Collisions

We study the P-odd effects related to the vorticity of the medium formed in noncentral heavy ion collisions. Using the kinetic Quark-Gluon Strings Model we perform the numerical simulations of the vorticity and hydrodynamical helicity for the various atomic numbers, energies and centralities. We observed the vortical structures typically occupying the relatively small fraction of the fireball volume. In the course of numerical simulations the noticeable hydrodanamical helicity was observed manifesting the specific mirror behaviour with respect to the reaction plane. The effect is maximal at the NICA and FAIR energy range.

nucl-th↗

arXiv2012

Quark-hadron duality, axial anomaly and mixing

Interplay between axial anomaly and quark-hadron duality in the presence of strong mixing is considered. The anomaly sum rule for meson transition form factors based on the dispersive representation of axial anomaly and quark-hadron duality in octet channel is analyzed. The comparison of this sum rule to the experimental data on $η$ and $η'$ mesons transition form factors shows that the interval of duality in this channel is rather small, contradicting the usual understanding of quark-hadron duality. The same values of interval of duality are supported by considering the two-point correlator in the local duality limit. This contradiction may be resolved by introducing of some nonperturbative non-OPE correction to the relevant spectral density. The form and value of this correction are discussed.

hep-ph↗

arXiv2010

Axial Anomaly and Transition Formfactors

We study photon-meson transition formfactors of light mesons in the kinematics, where one photon is real and other is virtual. Dispersive approach to axial anomaly leads to the anomaly sum rule. The absence of corrections to it allows us to get the relation between possible corrections to continuum and to lower states within QCD method which does not rely on factorization hypothesis. We show, relying on the recent data of the BaBar Collaboration, that the relative correction to continuum is quite small, and small correction to continuum can dramatically change the pion formfactor. The same effect for η meson is shown to be less pronounced.

hep-ph↗

arXiv2010

Polarisation effects in the central exclusive $χ_c$ production and the $J/ψ$ angular distributions

We discuss exclusive elastic double diffractive axial-vector $χ_c(1^+)$ and tensor $χ_c(2^+)$ mesons production for different meson polarisations in proton-(anti)proton collisions at the Tevatron energy. The amplitude for the process is derived within the $k_t$-factorisation approach using unintegrated gluon distributions (UGDFs). Differential cross sections for different $χ_c$ polarisations are calculated. Angular distributions of $J/ψ$ meson from the radiative $χ_c(1^+,2^+)$ decays are derived. Prospects for experimental selection of different spin states of $χ_c$ mesons are discussed.

hep-ph↗

arXiv2010

Spin effects in diffractive charmonia production

We consider exclusive double diffractive production of polarised axial-vector $χ_c(1^+)$ and tensor $χ_c(2^+)$ charmonia in proton-(anti)proton collisions at Tevatron energy. The corresponding amplitudes for these processes are derived within the $k_t$-factorisation approach. Contributions from different polarisation states of axial-vector and tensor charmonia are quantified. Corresponding experimental consequences are discussed.

hep-ph↗

arXiv2010

Chiral vortaic effect and neutron asymmetries at NICA

We study the possibility of testing experimentally signatures of P-odd effects related with the vorticity of the medium. The Chiral Vortaic Effect is generalized to the case of conserved charges different from the electric one. In the case of baryonic charge and chemical potential such effect should manifest itself in neutron asymmetries at the NICA accelerator complex measured by the MPD detector. The required accuracy may be achieved in a few months of accelerator running. We also discuss polarization of the hyperons and P-odd correlations of particle momenta (handedness) as probes of vorticity.

hep-ph↗

arXiv2010

Nucleon spin structure at low momentum transfers

The generalized Gerasimov-Drell-Hearn (GDH) sum rule is known to be very sensitive to QCD radiative and power corrections. We improve the previously developed QCD-inspired model for the $Q^2$-dependence of the GDH sum rule. We take into account higher order radiative and higher twist power corrections extracted from precise Jefferson Lab data on the lowest moment of the spin-dependent proton structure function $Γ_1^{p}(Q^2)$ and on the Bjorken sum rule $Γ_1^{p-n}(Q^2)$. By using the singularity-free analytic perturbation theory we demonstrate that the matching point between chiral-like positive-$Q^2$ expansion and QCD operator product $1/Q^2$-expansion for the nucleon spin sum rules can be shifted down to rather low $Q\simeqΛ_{QCD}$ leading to a good description of recent proton, neutron, deuteron and Bjorken sum rule data at all accessible $Q^2$.

hep-ph↗

arXiv2009

Colour Modification of Factorisation in Single-Spin Asymmetries

We discuss the way in which factorisation is partially maintained but nevertheless modified by process-dependent colour factors in hadronic single-spin asymmetries. We also examine QCD evolution of the twist-three gluonic-pole strength defining an effective T-odd Sivers function in the large-x limit, where evolution of the T-even transverse-spin DIS structure function g2 is known to be multiplicative.

hep-ph↗

arXiv2009

Non-Universality and Evolution of the Sivers Function

We examine the large-x QCD evolution of the twist-three gluonic-pole strength defining an effective T-odd Sivers function, where evolution of the T-even transverse-spin DIS structure function g2 is multiplicative. The result corresponds to a colour-factor modified spin-averaged twist-two evolution.

hep-ph↗