arXiv subjects

V. V. Skalozub

Publications and source records attributed to V. V. Skalozub.

At least 19 recordsLinked to original sources

arXiv2020

On plasmon contribution to the hot A_0 condensate

In SU(2) gluodynamics, the Debye gluon contribution W_D(A_0) to the effective action of the temporal gauge field component, A_0 = const, at high temperature is calculated in the background R^{xi} gauge. It is shown that at nonzero A_0 the standard definition k_0 = 0, |k| -> 0 corresponds to long distance correlations for the longitudinal in internal space gluons. The transversal gluons become screened by the A_0 background field. Therefore they give zero contributions and have to be excluded from the correlation corrections. The total effective action accounting for the one-loop, two-loop and correct W_D(A_0) satisfies Nielsen's identity that proves gauge invariance of the A_0 condensation phenomenon.

hep-ph↗

arXiv2013

A high statistics study of the beta-function in the SU(2) lattice thermodynamics

The beta-function is investigated on the lattice in SU(2) gluodynamics. It is determined within a scaling hypothesis while a lattice size fixed to be taken into account. The functions calculated are compared with the ones obtained in the continuum limit. Graphics processing units (GPU) are used as a computing platform that allows gathering a huge amount of statistical data. Numerous beta-functions are analyzed for various lattices. The coincidence of the lattice beta-function and the analytical expression in the region of the phase transition is shown. New method for estimating a critical coupling value is proposed.

hep-lat↗

arXiv2013

Effective mass of W-boson in a magnetic field

Simple representation for the average value of the W-boson one-loop polarization tensor in a magnetic field B=const, calculated in the ground state of the tree-level spectrum, is derived. It corresponds to Demeur's formula for electron in QED. The energy of this state, describing effective particle mass, is computed by solving the Schwinger-Dyson equation. As application, we investigate the effective mass squared at the threshold of the tree-level instability, $B \to B_c = m^2/e$, and show that it is positive. In this way the stability of the W-boson spectrum is established. Some peculiarities of the results obtained and other applications are discussed.

hep-ph↗

arXiv2009

Model independent search for Z'-boson signals

An approach to the model-independent searching for the Z' gauge boson as a virtual state in scattering processes is developed. It accounts for as a basic requirement the renormalizability of underlying unspecified in other respects model. This results in a set of relations between low energy couplings of Z' to fermions that reduces in an essential way the number of parameters to be fitted in experiments. On this ground the observables which uniquely pick out the Z' boson in leptonic processes are introduced and the data of LEP experiments analyzed. The Z' couplings to leptons and quarks are estimated at 95% confidence level. These estimates may serve as a guide for experiments at the Tevatron and/or LHC. A comparison with other approaches and results is given.

hep-ph↗

arXiv2009

Neural network predictions for Z' boson within LEP2 data set of Bhabha process

The neural network approach is applied to search for the Z'-boson within the LEP2 data set for e+ e- -> e+ e- scattering process. In the course of the analysis, the data set is reduced by 20 percent. The axial-vector and vector couplings of the Z' are estimated at 95 percent CL within a two-parameter fit. The mass is determined to be 0.53-1.05 TeV. Comparisons with other results are given.

hep-ph↗

arXiv2006

Z' signal from the LEP2 data

The many-parametric fit of the LEP2 data on e^+e^-\to e^+e^-, μ^+μ^-, τ^+τ^- processes is performed to estimate signals of the Abelian Z'-boson beyond the standard model. The model-independent relations between the Z' couplings to the standard model particles allow to describe the Z' effects in lepton processes by 4 independent parameters. No signal is found by the complete LEP2 data set, and the 1.3σsignal is detected by the fit of the backward bins. The Z' couplings to the vector and axial-vector lepton currents are constrained. The comparisons with the one-parameter fits and with the LEP1 experiments are performed.

hep-ph↗

arXiv2006

Signals of Z' boson in the Bhabha process within the LEP2 data set

The LEP2 data set on the Bhabha process is analyzed with the aim to detect the signals of the heavy virtual Z' gauge bosons. The state interacting with the left-handed standard-model doublets and called the Chiral Z' is investigated. This particle was introduced already as the low-energy state allowed by the renormalizability of the model. The contribution of the Chiral Z' state to the Bhabha process is described by two parameters: the coupling to electrons and the Z-Z' mixing angle. The sign-definite one-parameter observable is proposed to measure the Z' coupling to the electron current. The one-parameter fit of the data shows no signals of the particle. The alternative two-parameter fit of the differential cross-sections is also performed. It also shows no Chiral Z' signals. The comparisons with other fits are discussed.

hep-ph↗

arXiv2005

Pulse Propagation in Resonant Tunneling II

We consider the analytically solvable model of a Gaussian pulse tunneling through a transmission resonance with a general Fano characteristic. It is demonstrated that the transmitted pulse contains enough information to determine uniquely all parameters defining the Fano resonance. This is in contrast to the measurement of the static conductance. Our analytical model is in agreement with numerical data published recently for the limit of a Breit-Wigner resonance. We identify two opposite pulse propagation regimes: if the resonance is broad compared to the energetic width of the incident Gaussian pulse a weakly deformed and slightly delayed transmitted Gaussian pulse is found. In the opposite limit of a narrow resonance the dying out of the transmitted pulse is dominated by the slow exponential decay characteristic of a quasi-bound state with a long life time. In this regime we find characteristic interference oscillations.

cond-mat.mes-hall↗

arXiv2004

Model-independent search for the Abelian Z' boson in the Bhabha process

Model-independent observables to pick out the Abelian Z' signal in the Bhabha process are introduced at energies >= 200 GeV. They measure separately the Z'-induced vector and axial-vector four-fermion contact couplings. The analysis of the LEP2 data constrains the value of the Z'-induced vector four-fermion coupling at the 2-sigma confidence level that corresponds to the Abelian Z' boson with the mass of order 1 TeV.

hep-ph↗

arXiv2004

Pulse Propagation in Resonant Tunneling

We consider the analytically solvable model of a Gaussian pulse tunneling through a transmission resonance with a Breit-Wigner characteristic. The solution allows for the identification of two opposite pulse propagation regimes: if the resonance is broad compared to the energetic width of the incident Gaussian pulse a weakly deformed and slightly delayed transmitted Gaussian pulse is found. In the opposite limit of a narrow resonance the dying out of the transmitted pulse is dominated by the slow exponential decay characteristic of a quasi-bound state with a long life time (decaying state). We discuss the limitation of the achievable pulse transfer rate resulting from the slow decay. Finally, it is demonstrated that for narrow resonances a small second component is superimposed to the exponential decay which leads to characteristic interference oscillations.

cond-mat.mes-hall↗

arXiv2004

The polarization tensor of neutral gluons in external fields at high temperature

The one-loop polarization operator of neutral gluons in the background constant Abelian isotopic, $H_{3}$, and hypercharge, $H_{8}$, chromomagnetic fields combined with $A_0$ electrostatic potential at high temperature is calculated. The case when $A_0=0$ is investigated separately. The proper time method is applied. It is found that neutral gluons do not acquire magnetic masses in the background fields, in contrast to the charged ones. The application of the results are discussed.

hep-ph↗

arXiv2003

On generation of Abelian magnetic fields in SU(3) gluodynamics at high temperature

The vacuum state of SU(3) gluodynamics at high temperature is investigated. A consistent approach including the calculation of either the spontaneously generated constant chromomagnetic isotopic $H_{3}$ and hypercharge $H_{8}$ fields or the polarization operator of charged gluons in this background is applied. It is shown within the effective potential including the one-loop plus daisy diagrams that the specific values of the fields deliver a global minimum to free energy. The spectrum of the transversal charged modes is stable at high temperature due to a gluon magnetic mass accounting for the vacuum fields. This leads to stable chromomagnetic fields in the deconfinement phase of QCD. A comparison with the results of other approaches is done.

hep-ph↗

arXiv2003

Signals of the Abelian Z' boson within the analysis of the LEP2 data

The preliminary LEP data on the e^+e^- -> l^+l^- scattering are analysed to establish a model-independent search for the signals of virtual states of the Abelian Z' boson. The recently introduced observables give a possibility to pick up uniquely the Abelian Z' signals in these processes. The mean values of the observables are in accordance with the Z' existence. However, the accuracy of the experimental data is deficient to detect the signal at more than the 1σconfidence level. The results of other model-independent fits and further prospects are discussed.

hep-ph↗

arXiv2002

The spontaneous generation of magnetic fields at high temperature in a supersymmetric theory

The spontaneous generation of magnetic and chromomagnetic fields at high temperature in the minimal supersymmetric standard model (MSSM) is investigated. The consistent effective potential including the one-loop and the daisy diagrams of all bosons and fermions is calculated and the magnetization of the vacuum is observed. The mixing of the generated fields due to the quark and s-quark loop diagrams and the role of superpartners are studied in detail. It is found that the contribution of these diagrams increases the magnetic and chromomagnetic field strengths as compared with the case of a separate generation of fields. The magnetized vacuum state is found to be stable due to the magnetic masses of gauge fields included in the daisy diagrams. Applications of the results obtained are discussed. A comparison with the standard model case is done.

hep-ph↗

arXiv2002

Signals of the Abelian Z' boson within the model independent analysis of the LEP data

The preliminary LEP data set on the total cross sections and the forward-backward asymmetries of the $e^+e^-\to\bar{f}f$ processes are analysed to establish a model-independent search for the signals of the virtual Abelian Z' boson. The recently introduced observables giving possibility to pick up uniquely the Z' signals in these processes are used. The mean values of the observables are in accordance with the Z' detection at the $1σ$ accuracy. The results of other model-independent fits and further prospects are discussed.

hep-ph↗

arXiv2001

The spontaneous generation of magnetic and chromomagnetic fields at high temperature in the Standard Model

The spontaneous generation of the magnetic and chromomagnetic fields at high temperature is investigated in the Standard Model. The consistent effective potential including the one-loop and the daisy diagrams of all boson and fermion fields is calculated. The mixing of the generated fields due to the quark loop diagram is studied in detail. It is found that the quark contribution increases the magnetic and chromomagnetic field strengths as compared with the separate generation of fields. The magnetized vacuum state is stable due to the magnetic gauge field masses included in the daisy diagrams. Some applications of the results obtained are discussed.

hep-ph↗

arXiv2001

Model-independent search for the Abelian Z' boson and the LEP data

Model-independent search for the Abelian $Z'$ gauge boson virtual state based on the new observable in the processes $e^+ e^- \to l^+ l^-$ is analyzed for the LEP data. The observable is introduced by using following from renormalizability of an underlying theory the correlations between the parameters of the low energy effective Lagrangian and kinematics of the scattering processes. The central values of the observable are in accordance with the $Z'$ existence, although no real signal is found at the $1σ$ level. Lower limits at the 95% confidence level on the corresponding contact interaction scale are derived in the range of 15.6 - 18.6 TeV. Comparisons with other fits are done.

hep-ph↗

arXiv2001

Renormalizability and searching for Z' gauge bosons

New observables for searching for Z' virtual states in processes e^+e^-\to\bar{f}f are proposed. They are based on the relations following due to renormalizability of an underlying theory between the parameters of the low-energy effective Lagrangian. Two types of the Z' interactions are considered. The observables allow to pick up uniquely the signals of both Z' bosons. The search for the Z' at future linear colliders and the treating of the LEP data are discussed.

hep-ph↗