arXiv subjects
Publications and source records attributed to M. A. Trusov.
We estimate the cross sections for the inclusive production of $Θ^+$ and $Λ(1520)$ in $pp$ collisions at high energy using the $K$ exchange diagrams. We find that inclusive $Θ^+$ production should be at the level of 1 $μ$b at energies~ $\sqrt{s}~\gtrsim~10~{\rm GeV}$. The ratio of $Θ^+(1540)$ to $Λ(1520)$ production cross-sections is $\sim 1%$.
The masses of $uudd\bar s $, $uudd\bar d$ and $uuss\bar d$ pentaquarks are evaluated in a framework of both the Effective Hamiltonian approach to QCD and spinless Salpeter using the Jaffe--Wilczek diquark approximation and the string interaction for the diquark--diquark--antiquark system. The pentaquark masses are found to be in the region above 2 GeV. That indicates that the Goldstone boson exchange effects may play an important role in the light pentaquarks. The same calculations yield the mass of $[ud]^2\bar c$ pentaquark $\sim$ 3250 MeV and $[ud]^2\bar b$ pentaquark $\sim$ 6509 MeV.
Using the expansion of the baryon wave function in a series of products of single quark bispinors (Dirac orbitals), the nonsinglet axial and tensor charge of the nucleon are calculated. The leading term yields ${G_A}/{G_V} = 1.27$ and in good agreement with experiment. Calculation is essentially parameter-free and depends on the string tension $σ$ and $α_s$, fixed at standard values. The importance of lower Dirac bispinor component, yielding 18% to the wave function normalization is stressed.
The masses of $uudd\bar s $ and $uudd\bar d$ pentaquarks are evaluated in a framework of the Effective Hamiltonian approach to QCD using the Jaffe-Wilczek $[ud]^2\bar q$ approximation. The mass of the $[ud]^2\bar s$ state is found to be $\sim 300-500$ MeV higher than the observed $Θ^+(1540)$ mass.
We review the results obtained in an Effective Hamiltonian (EH) approach for the three-quark systems. The EH is derived starting from the Feynman--Schwinger representation for the gauge-invariant Green function of the three quarks propagating in the nonperturbative QCD vacuum and assuming the minimal area law for the asymptotic of the Wilson loop. It furnishes the QCD consistent framework within which to study baryons. The EH has the form of the nonrelativistic three-quark Hamiltonian with the perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. After outlining the approach, methods of calculations of the baryon eigenenergies and some simple applications are explained in details. With only two parameters: the string tension $σ=0.15 GeV^2$ and the strong coupling constant $α_s=0.39$ a unified quantitative description of the ground state light and heavy baryons is achieved. The prediction of masses of the doubly heavy baryons not discovered yet are also given. In particular, a mass of $3660 MeV$ for the lightest $Ξ_{cc}$ baryon is found by employing the hyperspherical formalism to the three quark confining potential with the string junction.
The simplest extension of the MSSM that does not contradict LEP II experimental bound on the lightest Higgs boson mass at $\tanβ\sim 1$ is the modified Next-to-Minimal Supersymmetric Standard Model (MNSSM). We investigate the renormalization of Yukawa couplings and soft SUSY breaking terms in this model. The possibility of $b$-quark and $τ$-lepton Yukawa coupling unification at the Grand Unification scale $M_X$ is studied. The particle spectrum is analysed in the vicinity of the quasi-fixed point where the solutions of renormalization group equations are concentrated at the electroweak scale.
The considerable part of the parameter space in the MSSM corresponding to the infrared quasi fixed point scenario is excluded by LEP II bounds on the lightest Higgs boson mass. In the NMSSM the mass of the lightest Higgs boson reaches its maximum value in the strong Yukawa coupling limit when Yukawa couplings are essentially larger than gauge ones at the Grand Unification scale. In this case the renormalization group flow of Yukawa couplings and soft SUSY breaking terms is investigated. The quasi-fixed and invariant lines and surfaces are briefly discussed. The coordinates of the quasi-fixed points, where all solutions are concentrated, are given.
Contents (Part 2): 8.Renormalization of Coupling Constants in the Minimal SUSY Models (R. B. Nevzorov, K. A. Ter-Martirosyan and M. A. Trusov) 9.Multiple Point Model and Phase Transition Couplings ...(L.V. Laperashvili, D.A. Ryzhikh and H.B. Nielsen) 10.Family Replicated Fit of All Quark and Lepton Masses and Mixings (H. B. Nielsen and Y. Takanishi) 11.Family Replicated Calculation of Baryogenesis (H. B. Nielsen and Y. Takanishi) 12. Neutrino Oscillations in Vacuum on the Large Distance (D.A. Ryzhikh and K.A. Ter-Martirosyan) 13. Possibility of an Additional Source of Time Reversal Violation for Neutrinos (R. Erdem) 14.Quark-Lepton Masses and the Neutrino Puzzle in the AGUT Model (C.D. Froggatt) 15.Neutrinos in the Family Replicated Gauge Group Model (C.D. Froggatt) (Contents of Part 1 [hep-ph/0301029]: 1.Derivation of Lorentz Invariance and Three Space Dimensions in Generic Field Theory (C D. Froggatt and H. B. Nielsen) 2.Unitary Representations, Noncompact Groups SO(q; d - q)...(N. Mankoc Borstnik, H. B. Nielsen and D. Lukman) 3.Weyl Spinor of SO(1; 13), Families of Spinors ...(A. Borstnik Bracic and N. Mankoc Borstnik) 4.A Tight Packing Problem (A. Kleppe) 5.Why so Few Particle Species? ... (D.L. Bennett and A. Kleppe) 6.About Number of Families (D. Lukman, A. Kleppe and N.S. Mankoc Borstnik) 7.Coupling Constant Unification in Spin-Charge Unifying Model ....(N. Mankoc Borstnik and H. B. Nielsen))
We present the results for the masses of the doubly heavy baryons $Ξ_{QQ'}$ and $Ω_{Q'Q}$ where $Q,Q'=b,c$ obtained in the framework of the simple approximation within the nonperturbative string approach.
We present some piloting calculations of the masses of the doubly heavy baryons in the framework of the simple approximation within the nonperturbative string approach. The simple analytical results for dynamical masses of heavy and light quarks and eigenvalues of the effective QCD Hamiltonian are presented.
In the strong Yukawa coupling limit the renormalization of trilinear couplings $A_i(t)$ and combinations of the scalar particle masses $\mathfrak{M}_i^2(t)$ are studied in the framework of the Next--to--Minimal SUSY Model. The dependence of given parameters on their initial values at the Grand Unification scale disappears when the solutions of the renormalization group equations approach the infrared quasi fixed points. Besides that at $\tildeα_{\text{GUT}}\ll Y_i(0)\ll 1$ in the vicinity of quasi fixed points $A_i(t)$ and $\mathfrak{M}_i^2(t)$ concentrated near lines or surfaces in the soft SUSY breaking parameter space. It occurs because the dependence of trilinear couplings and combinations of scalar particle mass on $A_i(0)$ and $\mathfrak{M}_i^2(0)$ disappears rather weakly. We propose a method which enables to obtain equations for such lines and surfaces. Their origin is also discussed by means of exact and approximate solutions of the NMSSM renormalization group equations.
Nowadays in the MSSM the moderate values of $\tanβ$ are almost excluded by LEP II lower bound on the lightest Higgs boson mass. In the Next-to-Minimal Supersymmetric Standard Model the theoretical upper bound on it increases and reaches maximal value in the strong Yukawa coupling limit when all solutions of renormalization group equations are concentrated near the quasi-fixed point. For calculation of Higgs boson spectrum the perturbation theory method can be applied. We investigate the particle spectrum in the framework of the modified NMSSM which leads to the self-consistent solution in the strong Yukawa coupling limit. This model allows one to get $m_h\sim 125$ GeV at values of $\tanβ\ge 1.9$. In the investigated model the lightest Higgs boson mass does not exceed $130.5\pm 3.5$ GeV. The upper bound on the lightest CP-even Higgs boson mass in more complicated supersymmetric models is also discussed.
The considerable part of the parameter space in the MSSM corresponding to the infrared quasi fixed point scenario is almost excluded by LEP II bounds on the lightest Higgs boson mass. In the NMSSM the mass of the lightest Higgs boson reaches its maximum value in the strong Yukawa coupling limit when Yukawa couplings are essentially larger than gauge ones at the Grand Unification scale. In this limit the solutions of the renormalisation group equations are attracted to the infrared and Hill type effective fixed lines or surfaces in the Yukawa coupling parameter space. They are concentrated in the vicinity of quasi fixed points for $Y_i(0)\to\infty$. However the solutions are attracted to such points rather weakly. For this reason when all $Y_i(0)\sim 1$ the solutions of the renormalisation group equations are gathered near a line in the Hill type effective surface. In the paper the approximate solutions for the NMSSM Yukawa couplings are given. The possibility of $b$--quark and $τ$--lepton Yukawa coupling unification at the scale $M_{X}$ is also discussed.
We present some piloting calculations of masses and short-range correlation coefficients for the ground states of light and heavy baryons in the framework of the simple approximation within the nonperturbative QCD approach.
The restrictions on the lightest Higgs boson mass in the minimal supersymmetric models are briefly reviewed. The particle spectrum is considered in the framework of the simplest modification of NMSSM that allows to avoid the domain wall problem and to get the self--consistent solution in the strong Yukawa coupling limit. The lightest Higgs boson mass in the investigated model can reach $125 GeV$ at values of $\tanβ\ge 1.9$ and does not exceed $130.5\pm 3.5 GeV$.
A theoretical analysis of solutions of renormalisation group equations in the MSSM corresponding to the quasi-fixed point conditions shows that the mass of the lightest Higgs boson in this case does not exceed $94\pm 5\text{GeV}$. It means that a substantial part of the parameter space of the MSSM is practically excluded by existing experimental data from LEP II. In the NMSSM the upper bound on the lightest Higgs boson mass reaches its maximum in the strong Yukawa coupling regime, when Yukawa constants are considerably larger the gauge ones on the Grand Unification scale. In this paper a particle spectrum in a simple modification of NMSSM which leads to a self-consistent solution in the considered region of the parameter space is studied. This model allows one to get $m_h\sim 125\text{GeV}$ even for comparatively low values of $\tanβ\ge 1.9$. For an analysis of the Higgs boson spectrum and neutralino spectrum a method for diagonalisation of mass matrices proposed formerly is used. The mass of the lightest Higgs boson in this model does not exceed $130.5\pm 3.5\text{GeV}$.
We present some piloting calculations of the short-range correlation coefficients for the light and heavy baryons and masses of the doubly heavy baryons $Ξ_{QQ'}$ and $Ω_{QQ'}$ ($Q,Q'=c,b$) in the framework of the simple approximation within the nonperturbative QCD approach.