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M. A. Trusov

Publications and source records attributed to M. A. Trusov.

At least 19 recordsLinked to original sources
arXiv2015

Confinement and $α_s$ in a strong magnetic field

Hadron decay widths are shown to increase in strong magnetic fields as $Γ(eB) \sim \frac{eB}κ Γ(0)$. The same mechanism is shown to be present in the production of the sea quark pair inside the confining string, which decreases the string tension with the growing $eB$ parallel to the string . On the other hand, the average energy of the $q\bar q$ holes in the string world sheet increases, when the direction of $\mathbf{B}$ is perpendicular to the sheet. These two effects stipulate the spectacular picture of the $\mathbf{B}$ dependent confinement and $α_s$, discovered on the lattice.

hep-ph↗
arXiv2014

Magnetic Moments of Negative Parity Baryons from Effective Hamiltonian Approach to QCD

Magnetic moments of $S_{11}(1535)$ and $S_{11}(1650)$ baryons are studied in the framework of the relativistic three-quark Hamiltonian derived in the Field Correlation Method. The baryon magnetic moments are expressed via the average current quark energies which are defined by the fundamental QCD parameters: the string tension $σ$, the quark masses, and the strong coupling constant $α_s$. For the $J^P=1/2^+$ baryon octet the approach was shown to give a good first approximation to the experimental moments. Resulting magnetic moments for the $J^P=1/2^-$ nucleons are compared both to model calculations and to those from lattice QCD.

hep-ph↗
arXiv2010

Nuclear matter at high density: Phase transitions, multiquark states, and supernova outbursts

Phase transition from hadronic matter to quark-gluon matter is discussed for various regimes of temperature and baryon number density. For small and medium densities, the phase transition is accurately described in the framework of the Field Correlation Method, whereas at high density predictions are less certain and leave room for the phenomenological models. We study formation of multiquark states (MQS) at zero temperature and high density. Relevant MQS components of the nuclear matter can be described using a previously developed formalism of the quark compound bags (QCB). Partial-wave analysis of nucleon-nucleon scattering indicates the existence of 6QS which manifest themselves as poles of $P$-matrix. In the framework of the QCB model, we formulate a self-consistent system of coupled equations for the nucleon and 6QS propagators in nuclear matter and the G-matrix. The approach provides a link between high-density nuclear matter with the MQS components and the cumulative effect observed in reactions on the nuclei, which requires the admixture of MQS in the wave functions of nuclei kinematically. 6QS determine the natural scale of the density for a possible phase transition into the MQS phase of nuclear matter. Such a phase transition can lead to dynamic instability of newly born protoneutron stars and dramatically affect the dynamics of supernovae. Numerical simulations show that the phase transition may be a good remedy for the triggering supernova explosions in the spherically symmetric supernova models. A specific signature of the phase transition is an additional neutrino peak in the neutrino light curve. For a Galactic core-collapse supernova, such a peak could be resolved by the present neutrino detectors. The possibility of extracting the parameters of the phase of transition from observation of the neutrino signal is discussed also.

hep-ph↗
arXiv2009

Quarks and baryons in QCD at finite density

The mechanism of string creation for light quarks developed earlier is considered for nonzero quark chemical potential. A strong modification of the confining string due to finite quark density (chemical quark potential $μ$) is observed. As a surprising result in a multiquark system with a common string junction an attractive well appears of radius $μ/σ$ and of an average depth equal to $μ$, which induces formation of multiquark hadrons. Preliminary estimates predict a new phase transition to multiquark hadron phase at rather high densities (in heavy ion collisions or in neutron stars) when neutron matter is compressed to 3-4 normal nuclear densities.

hep-ph↗
arXiv2009

Deconfinement and quark-gluon plasma

The theory of confinement and deconfinement is discussed as based on the properties of the QCD vacuum. The latter are described by field correlators of colour-electric and colour-magnetic fields in the vacuum, which can be calculated analytically and on the lattice. As a result one obtains a self-consistent theory of the confined region in the (mu,T) plane with realistic hadron properties. At the boundary of the confining region, the colour-electric confining correlator vanishes, and the remaining correlators describe strong nonperturbative dynamics in the deconfined region with (weakly) bound states. Resulting equation of state for mu=0, p(T), (epsilon-3P)/T are in good agreement with lattice data. Phase transition occurs due to evaporation of a part of the colour-electric gluon condensate, and the resulting critical temperatures T_c(mu) for different n_f are in good correspondence with available data.

hep-ph↗
arXiv2008

The coupled-channel analysis of $D_s$ and $B_s$ mesons

In the framework of the coupled channel model the mass shifts of the $P$--wave excitations of $D_s$ and $B_s$ mesons have been calculated. The corresponding coupling to $DK$ and $BK$ channels is provided by the effective chiral Lagrangian which is deduced from QCD and does not contain fitting parameters. The strong mass shifts down for $0^+$ and ${1^+}'$ states have been obtained, while ${1^+}"$ and $2^+$ states remain almost at rest. Two factors are essential for large mass shifts: strong coupling of the $0^+$ and $1^{+'}$ states to the $S$-wave decay channel, containing a Nambu-Goldstone meson, and the chiral flip transitions due to the bispinor structure of both heavy-light mesons. The masses $M(B^*_s(0^+))=5710(15)$ MeV and $M(B_s(1^{+'}))=5730(15)$ MeV are predicted. Experimental limit on the width $Γ(D_{s1}(2536))<2.3$ MeV puts strong restrictions on admittable mixing angle between the $1^+$ and $1^{+'}$ states.

hep-ph↗
arXiv2008

Chiral shifts in heavy-light mesons

The mass shifts of the $P$-wave $D_s$ and $B_s$ mesons due to coupling to $DK$ and $BK$ channels are calculated in the coupling channel model without fitting parameters. The strong mass shifts down for $0^+$ and ${1^+}'$ states have been obtained, while ${1^+}"$ and $2^+$ states remain almost in situ. The masses of $0^+$ and ${1^+}'$ states of $B_s$ mesons have been predicted.

hep-ph↗
arXiv2008

Heavy baryon spectroscopy in the QCD string model

QCD string model formulated in the framework of the Field Correlator Method (FCM) in QCD is employed to calculate the masses of $Σ_c$, $Ξ_c$ and recently observed at Tevatron $Σ_b$, $Ξ_b$ baryons and their orbital excitations. The auxiliary field formalism allows one to write a simple local form of the effective Hamiltonian for the three quark system, which comprises both confinement and relativistic effects, and contains only universal parameters: the string tension $σ$, the strong coupling constant $α_s$, and the bare (current) quark masses $m_i$. We calculate the hyperfine splitting with account of the both perturbative and non--perturbative spin-spin forces between quarks in a baryon. For the orbital excitations we estimate the string correction for the confinement potential - the leading correction to the contribution of the proper inertia of the rotating string. This correction lowers the masses of the P-states by 50 MeV. We find our numerical results to be in good agreement with experimental data.

hep-ph↗
arXiv2008

Feynman disentangling method and group theory

The subject of this work is to apply the modified Feynman disentangling approach to a problem of transitions in a non-quadratic quantum-mechanical system: a singular oscillator with a time-dependent frequency.

quant-ph↗
arXiv2008

Feynman operator calculus and singular quantum oscillator

New applications of Feynman disentangling method in quantum mechanics are studied and the time-dependent singular oscillator problem is solved in this approach. The important role of representation group theory is discussed in this context.

quant-ph↗
arXiv2007

The chiral transitions in heavy-light mesons

The mass shifts of the $P$-wave $D_s$ and $B_s$ mesons due to coupling to $DK$, $D^*K$ and $BK$, $B^*K$ channels are studied using the chiral quark-pion Lagrangian without fitting parameters. The strong mass shifts down $\sim 140$ MeV and $\sim 100$ MeV for $D^*_s(0^+)$ and $D_s(1^{+'})$ and $\sim 100$ MeV for $B^*_s(0^+)$ and $B_s(1^{+'})$ are calculated. Two factors are essential for large mass shifts: strong coupling of the $0^+$ and $1^{+'}$ states to the $S$-wave decay channel, containing a Nambu-Goldstone meson, and the chiral flip transitions due to the bispinor structure of both heavy-light mesons. The masses $M(B^*_s(0^+))=5695(10)$ MeV and $M(B_s(1^{+'}))=5730(15)$ MeV,very close to $M(B(0^+))$ and $M(B(1^{+'}))$, are predicted. Experimental limit on the width $Γ(D_{s1}(2536))<2.3$ MeV puts strong restrictions on admittable mixing angle between the $1^+$ and $1^{+'}$ states, $|ϕ|<6^{\circ}$, which corresponds to the mixing angle $θ$ between the $^3P_1$ and $^1P_1$ states, $29^{\circ}<θ< 41^{\circ}$.

hep-ph↗
arXiv2007

Vacuum phase transition at nonzero baryon density

It is argued that the dominant contribution to the interaction of quark gluon plasma at moderate $T\geq T_c$ is given by the nonperturbative vacuum field correlators. Basing on that nonperturbative equation of state of quark-gluon plasma is computed and in the lowest approximation expressed in terms of absolute values of Polyakov lines for quarks and gluons $L_{fund} (T); L_{adj}(T)=(L_{fund})^{9/4}$known from lattice and analytic calculations. Phase transition at any $μ$ is described as a transition due to vanishing of one of correlators, $ D^E(x)$, which implies the change of gluonic condensate $ΔG_2$. Resulting transition temperature $T_c(μ)$ is calculated in terms of $Δ$$G_2$ and $L_{fund}(T_c)$. The phase curve $T_c(μ)$ is in good agreement with lattice data. In particular $T_c(0)=0.27; 0.19; 0.17$ GeV for $n_f=0,2,3$ and fixed $ΔG_2=0.0035$ GeV$^4$.

hep-ph↗
arXiv2007

Deconfinement transition for nonzero baryon density in the Field Correlator Method

Deconfinement phase transition due to disappearance of confining colorelectric field correlators is described using nonperturbative equation of state. The resulting transition temperature $T_c(μ)$ at any chemical potential $μ$ is expressed in terms of the change of gluonic condensate $ΔG_2$ and absolute value of Polyakov loop $L_{fund} (T_c)$, known from lattice and analytic data, and is in good agreement with lattice data for $ΔG_2 \approx 0.0035 $ GeV$^4$. E.g. $T_c(0) =0.27; 0.19; 0.17$ GeV for $n_f=0,2,3$ respectively.

hep-ph↗
arXiv2006

Inclusive pentaquark and strange baryons production in hadron beam experiments at high energy

We estimate the high-energy behavior of the $Θ^+$ and $Λ(1520)$ production cross sections in inclusive $pp$ collisions using the $K$ exchange diagram. We show that the cross section of the $Θ^+$-production is suppressed compared to the production of $Λ(1520)$. As a byproduct we also estimate the contribution of the $π$ exchange diagram for the inclusive $Λ(1520)$ production in $Σp$ collisions.

hep-ph↗
arXiv2006

Inclusive pentaquark and strange baryons production in pp and Σp collisions at high energy

We calculate the cross sections for the inclusive production in the fragmentation region of $Θ^+(1540)$ and $Λ(1520)$ in $pp$ collisions and $Λ(1520)$ in $Σp$ collisions at high energy using the $K$- and $π$-meson exchange diagrams, respectively. The contributions of these diagrams survive at asymptotically large energies and are energy independent in this region up to logarithmic and power corrections. We find that inclusive $Θ^+(1540)$ production should be at the level of 1 $μ\mathrm{b}\timesΓ_{ΘKN}/ 1$ MeV. The ratio of the $Θ^+(1540)$ over the $Λ(1520)$ yields is found to be $\sim 1%$. The fraction of $Λ(1520)$ yields in $Σp$ and $pp$ collisions is $\sim 2.7$ that quantitatively agrees with the preliminary result of the Fermilab fixed target experiment E781.

hep-ph↗
arXiv2006

Nucleon matrix elements and baryon masses in the Dirac orbital model

Using the expansion of the baryon wave function in a series of products of single quark bispinors (Dirac orbitals), the nonsinglet axial and tensor charges of a nucleon are calculated. The leading term yields $g_A = 1.27$ in good agreement with experiment. Calculation is essentially parameter-free and depends only on the strong coupling constant value $α_s$. The importance of lower Dirac bispinor component, yielding 18% to the wave function normalization is stressed. As a check, the baryon decuplet masses in the formalism of this model are also computed using standard values of the string tension $σ$ and the strange quark mass $m_s$; the results being in a good agreement with experiment.

hep-ph↗