Study of the Confinement/Deconfinement Phase Transition in Rotating Lattice SU(3) Gluodynamics

JETP Letters - The effect of rotation on the confinement/deconfinement phase transition in SU(3) gluodynamics has been studied in lattice simulation in the rotating reference frame, where rotation...     

Anomalous three-boson coupling constants in the single production of W bosons at a future e + e − linear collider

The question of whether constraints on the anomalous parameters of WWγ and WWZ three-boson interactions can be deduced from an analysis of data on the reaction e ⁺ e ^? → W ^? e ⁺ ν that are expected to come from a future $\sqrt s = 500 - GeVe^ + e^ - $ linear collider of integrated luminosity of L=50, 100, or 500 fb^? is discussed. An analysis of relevant differential distributionns reveals that, in contrast to pair W-boson production, the reaction mentioned immediately above is highly sensitive to the parameter λ _Z and that the resulting constraints can be viewed as those that supplement the constraints that follow from data on e ⁺ e ^?→W ⁺ W ^?. For the experiment being discussed, two possible implementations of a detector are considered that correspond to the kinematical regions |cos $\left| {\cos \theta _{e^ + } } \right| \leqslant \cos 7^\circ $ and $\left| {\cos \theta _{e^ + } } \right| \leqslant \cos 1.5^\circ $ . It is indicated that the region of small positron-scattering angles is of importance for improving the sensitivity of the process. In setting constraints on the anomalous parameters, the SEWS scenario for anomalous boson coupling constants, where interactions responsible for electroweak-symmetry breaking are strongly coupled, is examined along with the case of the most general parametrization of the WWγ(Z) three-boson vertices.     

Muon transverse polarization in K_{l2_\gamma } decay due to the electromagnetic final-state interaction

For the decay process K ⁺ → μ ⁺ νγ, the effect of muon transverse polarization caused by electromagnetic final-state interaction is analyzed. It is shown that, in the one-loop approximation, the muon transverse polarization varies from ?1.3×10^?3 to zero in the region of the Dalitz plot. The mean value of the muon polarization, 〈P _T〉, in the kinematical region E _γ ≥20 MeV is ?5.44×10^?4.     

Double charmonium production in exclusive bottomonium decays

Exclusive bottomonium decays leading to the production of charmonium pairs are considered. The respective decay widths are calculatedwithin the approach of line-cone expansion for the amplitude and nonrelativistic QCD. It is shown that the production of L _z ≠ 0 P-wave charmonium states is possible even in the leading-twist approximation. This means a violation of selection rules that require the suppression of such decays. The reason for this violation is discussed in detail.     

Calculation of O(p6) corrections to the muon transverse polarization in Kl2γ decay

The contribution of final-state interactions to the muon transverse polarization in the decay K ⁺ → μ⁺ v γ is calculated within chiral perturbation theory to O(p ⁶) terms. It is shown that the O(p ⁶) corrections to the transverse polarization are much smaller than the O(p ⁴) leading contribution. Original Russian Text ? V.V. Braguta, A.A. Likhoded, A.E. Chalov, 2007, published in Yadernaya Fizika, 2007, Vol. 70, No. 2, pp. 386–391.     

Future e(+)e(-) colliders' sensitivity to Hbb coupling and CP violation

We perform a complete simulation of the process e(+)e(-)-->bbvv, where nu can be an electron, muon, or tau neutrino, in the context of a general Higgs coupling to b quarks. We parametrize the Hbb; coupling as (m(b)/v)(a+igamma(5)b). Taking into account interference effects between pure Higgs and Standard Model contributions, we find that sensitivities of the order of 2% and 20% can be obtained at a future e(+)e(-) collider for deviations of the a and b parameters, respectively, from their Standard Model values. Combining our analysis with an independent measurement of Gamma(H-->bb) can provide evidence about the CP nature of the Higgs sector.     

Transverse polarization of the lepton in the decay process <Emphasis Type="Italic">B</Emphasis> → <Emphasis Type="Italic">Dlν</Emphasis><Subscript>l</Subscript> due to electromagnetic final-state interaction

The emergence of transverse polarization of the lepton in the decay processes B⁰ → D^?l⁺ν_l and \(B^ + \to \bar D^0 l + \nu _l \) for l = τ, μ is studied on the basis of the Standard Model in the leading approximation of heavy-quark effective theory. It is shown that a nonzero transverse polarization appears owing to electromagnetic final-state interactions at the one-loop level. Diagrams involving D and D* mesons in the intermediate state and making a nonzero contribution to the transverse polarization of the outgoing lepton are considered. If only these mesons are taken into account in evaluating the mean values of the τ-lepton polarization in the decays B⁰→D^?τ⁺ν_τ and \(B^ + \to \bar D^0 \tau ^ + \nu _\tau \), the results are 2.60×10^-3 and ?1.59×10^?3, respectively. The corresponding values of the transverse muon polarization averaged over the Dalitz plot are 2.97×10^?4 and-6.79×10^?4.     

Numerical simulation of graphene in a magnetic field within the effective field theory

Monte Carlo simulation of graphene in an external magnetic field perpendicular to the plane of graphene has been reported. The calculations have been performed using the effective quantum field theory with a noncompact (3 + 1)-dimensional Abelian gauge field and (2 + 1)-dimensional Kogut-Susskind fermions. It has been revealed that the external magnetic field shifts the semimetal-insulator phase transition point toward higher dielectric constants of the substrate. The phase diagram of the semimetal-insulator phase transition has been plotted in the (dielectric constant of the substrate-magnetic field) plane.     

Calculation of the viscosity of SU(2) gluodynamics with the lattice simulation

The viscosity of SU(2) gluodynamics within the simulation of the lattice quantum chromodynamics at a temperature of T/T _c = 1.2 has been calculated with the Kubo formula relating the viscosity to the spectral function of the correlation function of the energy-momentum tensor. The correlation function of the energy-momentum tensor has been calculated using the numerical simulation of the lattice SU(2) gluodynamics on supercomputers.     

Exclusive processes of charmonium production and charmonium wave functions

Results obtained by studying the properties of the leading-twist wave functions for the S- and P-wave states of charmonia are presented. Wave-function models that can be used to calculate various processes involving the production of these mesons were constructed on the basis of these investigations. Calculations for some exclusive processes of charmonium production were performed within the models in question.