International Journal of Modern Physics A

The idea that the elementary particles might have the symmetry of knots has had a long history. In any modern formulation of this idea, however, the knot must be quantized. The present review is a summary of a small set of papers that began as an attempt to correlate the properties of quantized knots with empirical properties of the elementary particles. As the ideas behind these papers have developed over a number of years, the model has evolved, and this review is intended to present the model in its current form. The original picture of an elementary fermion as a solitonic knot of field, described by the trefoil representation of SUq(2), has expanded into its present form in which a knotted field is complementary to a composite structure composed of three preons that in turn are described by the fundamental representation of SLq(2). Higher representations of SLq(2) are interpreted as describing composite particles composed of three or more preons bound by a knotted field. This preon model unexpectedly agrees in important detail with the Harari–Shupe model. There is an associated Lagrangian dynamics capable in principle of describing the interactions and masses of the particles generated by the model.

A nonextensive statistical mechanics entropy that depends only on the probability distribution is proposed in the framework of superstatistics. It is based on a Γ(χ²) distribution that depends on β and also on p_l. The corresponding modified von Neumann entropy is constructed; it is shown that it can also be obtained from a generalized Replica trick. We further demonstrate a generalized H-theorem. Considering the entropy as a function of the temperature and volume, it is possible to generalize the equation of state of an ideal gas. Moreover, following the entropic force formulation a generalized Newton's law is obtained, and following the proposal that the Einstein equations can be deduced from the Clausius law, we discuss on the structure that a generalized Einstein's theory would have. Lastly, we address the question whether the generalized entanglement entropy can play a role in the gauge/gravity duality. We pay attention to 2d CFT and their gravity duals. The correction terms to the von Neumann entropy result more relevant than the usual UV ones and also than those due to the area dependent AdS₃ entropy which result comparable to the UV ones. Then the correction terms due to the new entropy would modify the Ryu–Takayanagi identification between the CFT entanglement entropy and the AdS entropy in a different manner than the UV ones or than the corrections to the AdS₃ area dependent entropy.

The production of both charged and neutral electroweak gauge bosons in association with b jets has attracted a lot of experimental and theoretical attention in recent years because of its central role in the physics programs of both the Fermilab Tevatron and the CERN Large Hadron Collider. The improved level of accuracy achieved both in the theoretical predictions and experimental measurements of these processes can promote crucial developments in modeling b-quark jets and b-quark parton distribution functions, and can provide a more accurate description of some of the most important backgrounds to the measurement of Higgs-boson couplings and several new physics searches. In this paper, we review the status of theoretical predictions for cross sections and kinematic distributions of processes in which an electroweak gauge boson is produced in association with up to two b jets in hadronic collisions, namely , pp → V + 1b jet and , pp → V + 2b jets with V = W^±, Z/γ*, γ. Available experimental measurements at both the Fermilab Tevatron and the CERN Large Hadron Collider are also reviewed and their comparison with theoretical predictions is discussed.

In this paper, we compute and discuss the differential cross-section of the Bhabha scattering in the framework of the z = 2 Lifshitz quantum electrodynamics (QED). We start by constructing the classical solutions for the fermionic fields, in particular the completeness relations, and also derive the theory's propagators. Afterwards, we compute the photon exchange and pair annihilation contributions for the Bhabha's process, and upon achieving the results we establish the magnitude of the theory's free parameter by looking for small deviations of the QED tree results.

The integral observables for model-independent detections of Abelian Z′ gauge boson in e⁺e^- → μ⁺μ^-(τ⁺τ^-) process with unpolarized beams at the ILC energies are proposed. They are based on the differential cross-section of deviations from the standard model predictions calculated with a low energy effective Lagrangian and taking into consideration the relations between the Z′ couplings to the fermions derived already. Due to these relations, the cross-section exhibits angular distribution giving a possibility for introducing one- or two-parameter observables which effectively fit the mass m_Z′, the axial-vector and the product of vector couplings v_ev_μ(v_ev_τ). A discovery reach for the Z′ is estimated for two of introduced observables. Determination of the basic Z′ model is discussed. Comparison with other results and approaches is given.

We study the theory of interaction between charged scalar field and Maxwell field in de Sitter background. Solving the equation of interacting fields, we define the in–out fields as asymptotic free fields and construct the reduction formalism for scalar field. Then we derive the perturbation expansion of the scattering operator. The first-order transition amplitudes corresponding to particle production from de Sitter vacuum and pair production in an external field are analyzed. We show that all these effects are important only in strong gravitational fields and vanish in the flat limit.

The two-flavor Polyakov-loop extended model is generalized by taking into account the effective four-quark vector-type interaction with the coupling strengths, which are endowed with a dependence on the Polyakov field Φ. The effective vertex generates entanglement interaction between the Polyakov loop and the chiral condensate. We investigate the influence of an additional quark vector interaction and the entanglement interaction on thermodynamics of a quark system and in particular on the location of the critical end-point at the given chemical potential or quark density. It is shown that the finite value of the singlet vector interaction strength G_v improves the model agreement with the lattice data. The influence of the nonzero G_v and entanglement on the thermodynamic observables and the curvature of the crossover boundary in the T – μ plane is also examined.

We reformulate the Lagrange deformed field–antifield BV-formalism suggested, in terms of the general Euler vector field N generated by the antisymplectic potential. That N generalizes, in a natural anticanonically-invariant manner, the usual power-counting operator. We provide for the "usual" gauge-fixing mechanism as applied to the deformed BV-formalism.

An independent quark model with a relativistic power-law potential is used to study the weak leptonic decays of light and heavy pseudoscalar mesons. The partial decay width and the decay constant for the weak leptonic decay are derived from the quark–antiquark momentum distribution amplitude which is obtained from the bound quark eigenfunction with the assumption of a strong correlation existing between quark–antiquark momenta inside the decaying meson in its rest frame. The model parameters are first determined from the application of the model to study the ground state hyperfine splitting of ρ, K, D, D_s, B, B_s and B_c mesons. The same model with no adjustable parameters is then used to evaluate the decay constants f_M and the decay widths of pseudoscalar mesons. The model predictions agree quite well with the available experimental data as well as with those of several other models. The decay constant for pion and kaon are obtained as f_π = 132 MeV and f_k = 161 MeV which closely agree with experimental values. But in case of heavier mesons for which experimental data are not yet available, the present model gives its predictions as f_BC > f_BS > f_B, f_DS > f_D, f_D > f_B and f_π > f_B which are in conformity with most of other model predictions. The model predictions of the corresponding decay widths and the branching ratios for the and decay modes are in close agreement with the available experimental data.

Nonlocal f(R) gravity was proposed as a powerful alternative to general relativity (GR). This theory has potentially adverse implications for infrared (IR) regime as well as ultraviolet (UV) early epochs. However, there are a lot of powerful features, making it really user-friendly. A scalar–tensor frame comprising two auxiliary scalar fields is used to reduce complex action. However, this is not the case for the modification complex which plays a distinct role in modified theories for gravity. In this work, we study the dynamics of a static, spherically symmetric object. The interior region of space–time had rapidly filled the perfect fluid. However, it is possible to derive a physically based model which relates interior metric to nonlocal f(R). The Tolman–Oppenheimer–Volkoff (TOV) equations would be a set of first-order differential equations from which we can deduce all mathematical (physical) truths and derive all dynamical objects. This set of dynamical equations govern pressure p, density ρ, mass m and auxiliary fields {ψ, ξ}. The full conditional solutions are evaluated and inverted numerically to obtain exact forms of the compact stars Her X-1, SAX J 1808.4-3658 and 4U 1820-30 for nonlocal Starobinsky model of f(◻^-1 R) = ◻^-1 R+α(◻^-1 R)². The program solves the differential equations numerically using adaptive Gaussian quadrature. An ascription of correctness is supposed to be an empirical equation of state for star which is informative in so far as it excludes an alternative nonlocal approach to compact star formation. This model is most suited for astrophysical observation.

Motivated by the recent measurements on nonleptonic J/ψ weak decays at BESIII and the potential prospects of J/ψ meson at the high-luminosity heavy-flavor experiments, the branching ratios of the two-body nonleptonic J/ψ → DP, DV decays are estimated quantitatively by considering the QCD radiative corrections to hadronic matrix elements with the QCD factorization approach. It is found that the Cabibbo favored , , decays have branching ratios ≳ 10^-10, which might be promisingly detectable in the near future.

The singly and doubly charged Higgs bosons (H^± and H^±±) are the typical particles predicted in the Higgs Triplet Model and the observation of these particles can be regarded as the direct evidence of new physics. In this paper, we focus on the study of the singly and doubly charged Higgs bosons associated production process: e⁺e^- → H⁺H^--W⁺. We present the production cross sections and the distributions of the transverse momenta and the rapidity distributions for outgoing particles. The numerical results show that the production rates can reach the level of several fb with reasonable parameter values. So, one can expect that enough signals could be produced in the future high-energy e⁺e^- collider experiments. The relevant SM backgrounds are also discussed in the case that the vacuum expectation value of the triplet is around 1 GeV.