International Journal of Modern Physics A

With multi-spinor fields which behave as triple-tensor products of the Dirac spinors, the Standard Model is extended so as to embrace three families of ordinary quarks and leptons in the visible sector and an additional family of exotic quarks and leptons in the dark sector of our Universe. Apart from the gauge and Higgs fields of the Standard Model symmetry G, new gauge and Higgs fields of a symmetry isomorphic to G are postulated to exist in the dark sector. It is the bi-quadratic interaction between visible and dark Higgs fields that opens a main portal to the dark sector. Breakdowns of the visible and dark electroweak symmetries result in the Higgs boson with mass 125 GeV and a new boson which can be related to the diphoton excess around 750 GeV. Subsequent to a common inflationary phase and a reheating period, the visible and dark sectors follow weakly-interacting paths of thermal histories. We propose scenarios for dark matter in which no dark nuclear reaction takes place. A candidate for the main component of the dark matter is a stable dark hadron with spin 3/2, and the upper limit of its mass is estimated to be 15.1 GeV/c².

The discovery of the Higgs particle is demanding a detailed knowledge of the properties of this fundamental component of the Standard Model. From the available data however, it cannot be concluded yet that we have found the SM Higgs boson and not one of the scalars postulated within the possible extensions of the SM. It is shown that a Higgs factory through a muon collider is particularly appropriate for precision studies of the properties of this particle. However sizable QED radiative effects — of order of 50% — must be carefully taken into account for a precise measurement of the leptonic and total widths of the Higgs particle. The results presented here are mainly based on a recent work in collaboration of Tao Han and Zhen Liu.

The present work attempts to provide an overview of texture specific mass matrices, which, along with Weak Basis (WB) transformations, emerge as a viable framework for explaining the fermion masses and mixing data in the quark as well as lepton sector.

In this paper, we study two generalized uncertainty principles (GUPs) including $[X,P]=i\hslash (1+\beta P^{2j})$ and $[X,P]=i\hslash (1+\beta P^2+k{\beta }^2{P}^4)$ which imply minimal measurable lengths. Using two momentum representations, for the former GUP, we find eigenvalues and eigenfunctions of the free particle and the harmonic oscillator in terms of generalized trigonometric functions. Also, for the latter GUP, we obtain quantum mechanical solutions of a particle in a box and harmonic oscillator. Finally we investigate the statistical properties of the harmonic oscillator including partition function, internal energy, and heat capacity in the context of the first GUP.

We discuss a question whether the observed Weinberg angle and Higgs mass are calculable in the formalism based on a construction in which the electroweak gauge group $SU(2)\times U{(1)}_Y$ is embedded in the graded Lie group $SU(2/1)$. Here, we follow original works of Ne’eman and Fairlie believing that bosonic fields take their values in the Lie superalgebra and fermionic fields take their values in its representation space. At the same time, our approach differs significantly. The main one is that while for them the gauge symmetry group is $SU(2/1)$, here we consider only symmetries generated by its even subgroup, i.e. symmetries of the standard electroweak model. The reason is that such formalism fixes the quartic Higgs coupling and at the same time removes the sign and statistics problems. The main result is that the presented model predicts values of the Weinberg angle and the Higgs mass correctly up to the two-loop level. Moreover, the model sets the unification scale coinciding with the electroweak scale and automatically describes the fermions correctly with the correct quark and lepton charges.

We study the energy loss rate (ELR) of the accelerated quark in terms of the holographic models for the two different motions, linear acceleration and uniform rotation. They are examined by two different nonconformal models with confinement. We found in both models that the value of ELR is bounded from below by the string tension of the linear confinement potential between quark and antiquark. The lower bounds of ELR are independent of the types of the motion of the quark. They are determined by the string tension at the worldsheet horizon of the model. These results are obtained when the model has the diagonal background metric. Then we find the common perspective for the lower bounds of ELRs of the two different motions.

The effective chiral Lagrangian in both nonlocal form $L_{\mathrm{\text{ECCL}}}$ and standard local form $L_{\mathrm{\text{ECL}}}$, derived in the vacuum correlator formalism in QCD, is studied in the chiral perturbation theory. It is shown, that all coefficients of $L_{\mathrm{\text{ECL}}}$ can be computed via $q\bar{q}$ Green’s functions. In the $p^2$ order of $L_{\mathrm{\text{ECL}}}$ one obtains GOR relations and quark decay constants $f_a$ are calculated $a=1,\dots ,8$, while in the $p^4$ order the coefficients $L_1$, $L_2$, $L_3$, $L_4$, $L_5$, $L_6$ are obtained in good agreement with the values given by data. The chiral quark model is shown to be a simple consequence of $L_{\mathrm{\text{ECCL}}}$ with defined coefficients. It is demonstrated that $L_{\mathrm{\text{ECCL}}}$ gives an extension of the limiting low-energy Lagrangian $L_{\mathrm{\text{ECL}}}$ to arbitrary momenta.

In this paper, we realize the Lie algebra $gl(\infty )$ in one homotopy category, and we find that tau functions can be obtained from complexes in this homotopy category by taking Grothendieck group. We start with the realization of Fermions in a homotopy category over a Heisenberg category which is constructed by Khovanov.

The inclusion of elastic rescattering and annihilation of quark–antiquarks pairs in final state can explain the $t$-dependency for cross-section ratio of $\eta$ and ${\eta }^{\prime }$ mesons in charge exchange reaction. The estimation for mixing angle $\eta -{\eta }^{\prime }$ with isoscalar states $ūu+\bar{d}d$ and hidden strangeness $\bar{s}s$ has been obtained. The consistent description of $\eta$ and ${\eta }^{\prime }$ meson outputs in $B^0$, $B_s^0$ and $J/\psi$ decays was also considered.

We consider the measurement of the trilinear couplings of the neutral Higgs bosons in the minimal supersymmetric standard model (MSSM) at a high energy $e^{+}{e}^{-}$ linear collider in the light of the discovery of a Higgs boson at the CERN Large Hadron Collider (LHC). We identify the state observed at the LHC with the lightest Higgs boson $(h^0)$ of the MSSM, and impose the constraints following from this identification, as well as other experimental constraints on the MSSM parameter space. In order to measure trilinear neutral Higgs couplings, we consider different processes where the heavier Higgs boson $(H^0)$ of the MSSM is produced in electron–positron collisions, which subsequently decays into a pair of lighter Higgs boson. We identify the regions of the MSSM parameter space where it may be possible to measure the trilinear couplings of the Higgs boson at a future electron–positron collider. A measurement of the trilinear Higgs couplings is a crucial step in the construction of the Higgs potential, and hence in establishing the phenomena of spontaneous symmetry breaking in gauge theories.