We extend the concept of matter parity $P_M=(-1{)}^{3(B-L)}$ to nonsupersymmetric theories and argue that $P_M$ is the natural explanation to the existence of dark matter of the Universe. We show that the nonsupersymmetric dark matter must be contained in a scalar $\mathbf{16}$ representation(s) of $SO(10)$, thus the unique low-energy dark matter candidates are $P_M$-odd complex scalar singlet(s) $S$ and an inert scalar doublet(s) $H_2$. We have calculated the thermal relic dark matter (DM) abundance of the model and shown that its minimal form may be testable at LHC via the standard model (SM) Higgs boson decays $H_1\to \mathrm{DM}\mathrm{DM}$. The PAMELA anomaly can be explained with the decays $\mathrm{DM}\to \nu lW$ induced via seesawlike operator which is additionally suppressed by the Planck scale. Because the SM fermions are odd under matter parity too, the DM sector is just our scalar relative.

We study the SU(3) lattice gauge theory, with two flavors of sextet Wilson-clover fermions, near its finite-temperature phase transition. We find metastable states that have Wilson line expectation values whose complex phases are near $\pm 2\pi /3$ or $\pi$. The true equilibrium phase at these couplings and temperatures has its Wilson line oriented only towards the positive real axis, in agreement with perturbation theory.

We study the pseudoscalar glueball ground state in a chiral effective Lagrangian model proposed by ’t Hooft, motivated by taking into account the instanton effects, which can describe not only the chiral symmetry breaking, but also the solution of $U_A(1)$. We study the parameter space allowed by constraints from vacuum conditions and unitary bounds. By considering two scenarios in the $0^{++}$ sector, we find that parameter space which can accommodate the $0^{-+}$ sector is sensitive to the conditions in $0^{++}$ sector. From our analysis, it is found that three $\eta$ states, i.e. $\eta (1295)$, $\eta (1405)$, $\eta (1475)$, can be the pseudoscalar glueball ground state if we assume that the lightest $0^{++}$ glueball ground state has a mass 1710 (or 1500) MeV. While there will be no $0^{-+}$ glueball candidate ground state found in experiments if we assume that the lightest $0^{++}$ glueball ground state has a mass 660 MeV. We also point out the determined instanton density (i.e. the parameter $k_t$) is consistent with those determined from other methods, e.g. instanton liquid approximation and lattice simulations.

New FOCUS data on $D^{+}\to K^{-}{\pi }^{+}{\pi }^{+}$ are fitted to the $\kappa$, together with earlier data from LASS, E791 and BES 2. There is a clear low mass $K\pi$ peak due to the $\kappa$ pole. Inclusion of the $I=3/2K\pi$ amplitude gives only a marginal improvement to the fit and almost no change to the $\kappa$ peak. An improved formula for the $\kappa$ gives a better fit than that used earlier. The $\kappa$ pole moves to $663\pm 8(\mathrm{stat})\pm 34(\mathrm{syst})-i[329\pm 5(\mathrm{stat})\pm 22(\mathrm{syst})]\mathrm{MeV}$. The $K_0(1430)$ pole is at $1427\pm 4(\mathrm{stat})\pm 13(\mathrm{stat})-i[135\pm 5(\mathrm{stat})\pm 20(\mathrm{syst})]\mathrm{MeV}$.

We present results of computing the $p^6$ order low energy constants in the normal part of chiral Lagrangian both for two and three flavor pseudoscalar mesons. This is a generalization of our previous work on calculating the $p^4$ order coefficients of the chiral Lagrangian in terms of the quark self-energy $\Sigma (p^2)$. We show that most of our results are consistent with those we can find in the literature.

The rate of $e^{+}{e}^{-}$ pair creation by external electric field in the presence of an incident photon beam is calculated for the photon energy far below the threshold, $\omega \ll m$, and the field strength small as compared to the critical one, $eE\ll m^2$. We find the pair production rate using a recently developed method based on calculation of the process in a thermal bath with subsequent identification of the contribution of single-photon states. We demonstrate that a nontrivial dependence on the ratio of the small parameters, $\omega m/(eE)$, emerges in this approach from an essentially (semi)classical calculation.

We consider supersymmetric models that include particles beyond the minimal supersymmetric standard model (MSSM) with masses in the TeV range, and that couple significantly to the MSSM Higgs sector. We perform a model-independent analysis of the spectrum and couplings of the MSSM Higgs fields, based on an effective theory of the MSSM degrees of freedom. The tree-level mass of the lightest $CP$-even state can easily be above the LEP bound of 114 GeV, thus allowing for a relatively light spectrum of superpartners, restricted only by direct searches. The Higgs spectrum and couplings can be significantly modified compared to the MSSM ones, often allowing for interesting new decay modes. We also observe that the gluon fusion production cross section of the SM-like Higgs can be enhanced with respect to both the standard model and the MSSM.

In this work, we explicitly evaluate the gauge propagator of the Maxwell theory supplemented by the $CPT$-even term of the standard model extension. First, we specialize our evaluation for the parity-odd sector of the tensor $W_{\mu \nu \rho \sigma }$, using a parametrization that retains only the three nonbirefringent coefficients. From the poles of the propagator, it is shown that physical modes of this electrodynamics are stable, noncausal and unitary. In the sequel, we carry out the parity-even gauge propagator using a parametrization that allows to work with only the isotropic nonbirefringent element. In this case, we show that the physical modes of the parity-even sector of the tensor $W$ are causal, stable and unitary for a limited range of the isotropic coefficient.

This is a more detailed version of our recent paper where we proposed, from first principles, a direct method for evaluating the exact fermion propagator in the presence of a general background field at finite temperature. This can, in turn, be used to determine the finite temperature effective action for the system. As applications, we discuss the complete one loop finite temperature effective actions for $0+1$ dimensional QED as well as for the Schwinger model in detail. These effective actions, which are derived in the real time (closed time path) formalism, generate systematically all the Feynman amplitudes calculated in thermal perturbation theory and also show that the retarded (advanced) amplitudes vanish in these theories. Various other aspects of the problem are also discussed in detail.

The Gross-Neveu model in $1+1$ dimensions is generalized to the case of different scalar and pseudoscalar coupling constants. This enables us to interpolate smoothly between the standard massless Gross-Neveu models with either discrete or continuous chiral symmetry. We present the solution of the generalized model in the large $N$ limit including the vacuum, fermion-antifermion scattering and bound states, solitonic baryons with fractional baryon number and the full phase diagram at finite temperature and chemical potential.

We present a comprehensive, nonperturbative analytical method to investigate the dynamics of time-dependent oscillating scalar field configurations. The method is applied to oscillons in a ${\varphi }^4$ Klein-Gordon model in two and three spatial dimensions, yielding high accuracy results in the characterization of all aspects of the complex oscillon dynamics. In particular, we show how oscillons can be interpreted as long-lived perturbations about an attractor in field configuration space. By investigating their radiation rate as they approach the attractor, we obtain an accurate estimate of their lifetimes in $d=3$ and explain why they seem to be perturbatively stable in $d=2$, where $d$ is the number of spatial dimensions.

High-accuracy binary black hole simulations are presented for black holes with spins anti-aligned with the orbital angular momentum. The particular case studied represents an equal-mass binary with spins of equal magnitude $S/m^2=0.43757\pm 0.00001$. The system has initial orbital eccentricity $\sim 4\times {10}^{-5}$, and is evolved through 10.6 orbits plus merger and ringdown. The remnant mass and spin are $M_f=(0.961109\pm 0.000003)M$ and $S_f/M_f{}^2=0.54781\pm 0.00001$, respectively, where $M$ is the mass during early inspiral. The gravitational waveforms have accumulated numerical phase errors of $\lesssim 0.1$ radians without any time or phase shifts, and $\lesssim 0.01$ radians when the waveforms are aligned with suitable time and phase shifts. The waveform is extrapolated to infinity using a procedure accurate to $\lesssim 0.01$ radians in phase, and the extrapolated waveform differs by up to 0.13 radians in phase and about 1% in amplitude from the waveform extracted at finite radius $r=350M$. The simulations employ different choices for the constraint damping parameters in the wave zone; this greatly reduces the effects of junk radiation, allowing the extraction of a clean gravitational wave signal even very early in the simulation.

We study the weak gravitational lensing effects caused by a stochastic distribution of dark matter halos. We develop a simple approach to calculate the magnification probability distribution function which allows us to easily compute the magnitude bias and dispersion for an arbitrary data sample and a given universe model. As an application we consider the effects of single-mass large-scale cosmic inhomogeneities ($M\sim {10}^{15}{h}^{-1}{M}_{\odot }$) to the SNe magnitude-redshift relation, and conclude that such structures could bias the PDF enough to affect the extraction of cosmological parameters from the limited size of present-day SNe data samples. We also release $\mathtt{t}\mathtt{u}\mathtt{r}\mathtt{b}\mathtt{o}\mathtt{G}\mathtt{L}$ [$\mathtt{t}\mathtt{u}\mathtt{r}\mathtt{b}\mathtt{o}\mathtt{G}\mathtt{L}$ is available at: http://www.turbogl.org.], a simple and very fast ($\lesssim 1\mathrm{s}$) Mathematica code based on the method here presented.

We obtain a general parametrization for the neutrino Majorana mass matrix in which all possible deviations from tribimaximal mixing are given by three complex parameters, and the deviation from each tribimaximal mixing eigenvector is identified with precisely two of them. This parametrization provides a useful tool for classifying the corrections to exact tribimaximal mixing in flavor models.

It has been suggested that the volume dependence of the spectral weight could be utilized as a probe to distinguish single and multiparticle states in Monte Carlo simulations. In a recent study using a solvable model, the Lee model, we found that this criteria is not applicable for broad resonances. In this paper, the same question is addressed within the finite-size formalism outlined by Lüscher. A similar conclusion has been reached. This is first studied using a quantum-mechanical scattering model. Then, following analogous arguments as in the original Lüscher’s formalism, the result is generalized to massive quantum field theories under the same conditions as the conventional Lüscher’s formulas. A possibility of extracting resonance parameters using the spectral weight function is also pointed out.

We discuss the decay of $B_c$ mesons into two light mesons $(\pi ,K^{(*)},{\eta }^{(\prime )},\rho ,\omega ,\varphi )$. All these decay channels come from a single type of diagram, namely, tree annihilation. This allows us to derive extremely simple $SU(3)$ relations among these processes. The size of annihilation contributions is an important issue in $B$ physics, and we provide two different estimates in the case of nonleptonic charmless $B_c$ decays, either a comparison with annihilation decays of heavy-light mesons or a perturbative model inspired by QCD factorization. We finally discuss a possible search for these channels at LHCb.

The QCD sum rule technique is employed to investigate pentaquark states with strangeness $S=+1$ and $I{J}^{\pi }=0{\frac{1}{2}}^{\pm }$, $1{\frac{1}{2}}^{\pm }$, $0{\frac{3}{2}}^{\pm }$, $1{\frac{3}{2}}^{\pm }$. Throughout the calculation, emphasis is laid on the establishment of a valid Borel window, which corresponds to a region of the Borel mass, where the operator product expansion converges and the presumed ground state pole dominates the sum rules. Such a Borel window is achieved by constructing the sum rules from the difference of two independent correlators and by calculating the operator product expansion up to dimension 14. Furthermore, we discuss the possibility of the contamination of the sum rules by possible $KN$ scattering states. As a result, we conclude that the $0{\frac{3}{2}}^{+}$ state seems to be the most probable candidate for the experimentally observed ${\Theta }^{+}(1540)$, while we also obtain states with $0{\frac{1}{2}}^{-}$, $1{\frac{1}{2}}^{-}$, $1{\frac{3}{2}}^{+}$ at somewhat higher mass regions.

The ratio $r$ of intercept to slope of the Pomeron trajectory is derived in a QCD inspired parton model approach to diffraction based on a (re)normalization of the $pp/\overline{p}p$ single-diffractive cross section designed to enforce unitarity constraints by eliminating overlapping rapidity gaps. As the collision energy increases, the renormalized single-diffractive cross section tends to a constant which depends on the ratio $r$. Identifying the constant as the ${\sigma }_o$ of the total cross section, $\sigma ={\sigma }_o·s^{ϵ}$, yields the ratio $r$ in terms of measured parameters that can be phenomenologically expressed in terms of the pion mass and QCD color factors. The result agrees with the measured value of $r$.

Recent numerical investigations have uncovered a surprising result: Reissner-Nordström-de Sitter black holes are unstable for spacetime dimensions larger than 6. Here we prove the existence of such instability analytically, and we compute the time scale in the near-extremal limit. We find very good agreement with the previous numerical results. Our results may be helpful in shedding some light on the nature of the instability.