Chern-Simons quantum mechanics is generalized to the noncommutative plane in this paper. Compared with the commutative counterpart, we find that in addition to the mass of the charged particle, there is a dimensionless parameter which behaves interestingly when it takes zero value. We study this model from both classical and quantum aspects. We show that the classical theory has continuous limits when both the parameters tend to zero while the quantum aspect (energy spectra) does not have. We must regularize the spectra of the full theory properly when these parameters tend to zero in order to get the finite results. We resort to the Dirac theory and the Faddeev-Jackiw reduction, respectively, to show that the regularization we made is proper.

In this paper, we investigate the vacuum energies of several models of quantum fields interacting with static external currents (linear couplings) concentrated along parallel branes with an arbitrary number of codimensions. We show that we can simulate the presence of static charges distributions as well as the presence of classical static dipoles in any dimension for massive and massless fields. We also show that we can produce confining potentials with massless self-interacting scalar fields as well as long range anisotropic potentials.

In the holographic model of QCD, $\theta$ dependence sharply changes at the point of confinement-deconfinement phase transition. In large $N$ QCD such a change in $\theta$ behavior can be related to the breakdown of the instanton expansion at some critical temperature $T_c$. Associating this temperature with confinement-deconfinement phase transition leads to the description of the latter in terms of dissociation of instantons into the fractionally charged instanton quarks. To elucidate this picture, we introduce the nonvanishing chiral condensate in the deconfining phase and assume a specific Lagrangian for the ${\eta }^{\prime }$ field in the confining phase. In the resulting picture the high-temperature phase of the theory consists of the dilute gas of instantons, while the low-temperature phase is described in terms of freely moving fractional instanton quarks.

We investigate five-dimensional rotating and charged black holes with squashed horizons in Gödel universes. The general solution was recently derived by applying a squashing transformation on the general nonextremal charged and rotating black hole in the Gödel universe found by Wu. We give a discussion of the squashed geometry and also consider its lift to ten dimensions and discuss the $T$-dual geometry. Finally, using the counterterms method we compute its conserved charges and explore its thermodynamics.

Considering a generalized action for the Einstein-Maxwell theory in four dimensions coupled to scalar and pseudoscalar fields, the thermodynamic properties of asymptotically flat black hole solutions in such a background are investigated. Bekenstein-Hawking area-entropy law is verified for these class of black holes. From the property of specific heat, it is shown that such black holes can be stable for a certain choice of the parameters like charge, mass, and the scalar vacuum expectation value. The possibility of a black hole phase transition is discussed in this context.

The fulfillment of the space-asymptotic Poincaré algebra is used to derive new higher-order-in-spin interaction Hamiltonians for binary black holes in the Arnowitt-Deser-Misner canonical formalism almost completing the set of the formally $1/c^4$ spin-interaction Hamiltonians involving nonlinear spin terms. To linear order in $G$, the expressions for the $S^{3}p$ and the $S^2{p}^2$ Hamiltonians are completed. It is also shown that there are no quartic nonlinear $S^4$ Hamiltonians to linear order in $G$.

We construct domain walls and instantons in a class of models with coupled scalar fields, determining, in agreement with previous studies, that many such solutions contain naked timelike singularities. Vacuum bubble solutions of this type do not contain a region of true vacuum, obstructing the ability of eternal inflation to populate other vacua. We determine a criterion that potentials must satisfy to avoid the existence of such singularities and show that many domain wall solutions in type IIB string theory are singular.

Previously, it has been argued that the anomalous emission from the region around the Galactic Center observed by WMAP, known as the “WMAP Haze,” may be the synchrotron emission from relativistic electrons and positrons produced in dark matter annihilations. In particular, the angular distribution, spectrum, and intensity of the observed emission are consistent with the signal expected to result from a weakly interactive massive particle with an electroweak-scale mass and an annihilation cross section near the value predicted for a thermal relic. In this article, we revisit this signal within the context of supersymmetry and evaluate the parameter space of the constrained minimal supersymmetric standard model. We find that, over much of the supersymmetric parameter space, the lightest neutralino is predicted to possess the properties required to generate the WMAP Haze. In particular, the focus point, $A$-funnel, and bulk regions (in which the neutralino annihilation cross section is of the order of $3\times {10}^{-26}{\mathrm{cm}}^3/\mathrm{s}$) typically predict a neutralino with a mass, annihilation cross section, and dominant annihilation modes which are within the range required to produce the observed features of the WMAP Haze. The stau-coannihilation region (in which the annihilation is suppressed), in contrast, is disfavored as an explanation for the origin of this signal.

A simple model is discussed to give rise to successful reheating in chaotic D-term inflation with a quadratic inflaton potential, introducing a trilinear coupling in the Kähler potential. Leptogenesis through the inflaton decay is also discussed in this model.

The primordial curvature fluctuation spectrum is reconstructed by the cosmic inversion method using the five-year Wilkinson Microwave Anisotropy Probe data of the cosmic microwave background temperature anisotropy. We apply the covariance matrix analysis and decompose the reconstructed spectrum into statistically independent band-powers. The statistically significant deviation from a simple power-law spectrum suggested by the analysis of the first-year data is not found in the five-year data except possibly at one point near the border of the wave number domain where accurate reconstruction is possible.

We write out the generic Dirac neutrino mass operator which possesses the Friedberg-Lee symmetry and find that its corresponding neutrino mass matrix is asymmetric. Following a simple way to break the Friedberg-Lee symmetry, we calculate the neutrino mass eigenvalues and show that the resultant neutrino mixing pattern is nearly tri-bimaximal. Imposing the Hermitian condition on the neutrino mass matrix, we also show that the simplified ansatz is consistent with current experimental data and favors the normal neutrino mass hierarchy.

Transverse polarization in the hyperon ($\Lambda$) production in the unpolarized deep inelastic scattering and $pp$ collisions is studied in the twist-three approach, considering the contribution from the quark-gluon-antiquark correlation distribution in nucleon. We further compare our results for deep inelastic scattering to a transverse momentum dependent factorization approach, and find consistency between the two approaches in the intermediate transverse momentum region. We also find that in $pp$ collisions, there are only derivative terms contributions, and the nonderivative terms vanish.

The differential cross section for the dilepton production is calculated, including Fermi motion of hadron constituents as well as emission from the ladders in the formalism of unintegrated parton distributions. We use unintegrated parton distributions which fulfill Kwieciński evolution equations. Both zeroth- and first-order (for matrix element) contributions are included. We calculate azimuthal angular correlations between charged leptons and deviations from the $p_t(l^{+})=p_t(l^{-})$ relation. We concentrate on the distribution in the dilepton-pair transverse momentum. We find incident energy and virtuality dependence of the distribution in the transverse momentum of the lepton pair. We study also azimuthal correlations between jet and dilepton pairs and correlation in the $(p_{1t}(\mathrm{\text{jet}}),p_{2t}(l^{+}{l}^{-}))$ space. The results are compared with experimental data of the R209 and UA1 collaborations.

We study fermion mass matrices of the cascade form which are compatible with the tribimaximal lepton mixing and generation mass hierarchy. The flat-cascade lepton matrices imply a parameter-independent relation among the mixing angles and mass eigenvalues. The relation has several indications that the atmospheric neutrino mixing angle is close to maximal and the other two angles have a correlation independently of neutrino mass eigenvalues. We also discuss phenomenological aspects of the cascade matrices; flavor-violating rare decays of charged leptons, thermal leptogenesis, and leptonic $CP$ violation. Possible dynamical origins of the cascades are illustrated based on flavor symmetry and in higher-dimensional theory.

We examine the thermodynamics and stability of 5-dimensional flat anti–de Sitter (AdS) black strings, locally asymptotically anti–de Sitter spacetimes whose spatial sections are AdS black holes with Ricci flat horizons. We find that there is a phase transition for the flat AdS black string when the AdS soliton string is chosen as the thermal background. We find that this bulk phase transition corresponds to a 4-dimensional flat AdS black hole to AdS soliton phase transition on the boundary Karch-Randall branes. We compute the possibility of a phase transition from a flat AdS black string to a 5-dimensional AdS soliton and show that, though possible for certain thin black strings, the transition to the AdS soliton string is preferred. In contrast to the case of the Schwarzschild-AdS black string, we find that the specific heat of the flat AdS black string is always positive; hence it is thermodynamically stable. We show numerically that both the flat AdS black string and AdS soliton string are free of a Gregory-Laflamme instability for all values of the mass parameter. Therefore thermodynamic stability implies perturbative stability for this spacetime. This may indicate that a generalization of the Gubser-Mitra conjecture, in which the assumption of a translational killing vector is weakened to that of a conformal killing vector of translational form, holds under certain conditions.

We study the impact of the capture and annihilation of weakly interacting massive particles (WIMPs) on the evolution of Population III stars. With a suitable modification of the Geneva stellar evolution code, we study the evolution of 20 and $200M_{\odot }$ stars in dark matter halos with densities between ${10}^8$ and ${10}^{11}\mathrm{GeV}/{\mathrm{cm}}^3$ during the core H-burning phase, and, for selected cases, until the end of the core He-burning phase. We find that for WIMP densities higher than 5.3 ${10}^{10}({\sigma }_p^{\mathrm{SD}}/{10}^{-38}{\mathrm{cm}}^2{)}^{-1}\mathrm{GeV}{\mathrm{cm}}^{-3}$ the core H-burning lifetime of $20M_{\odot }$ and $200M_{\odot }$ stars exceeds the age of the Universe, and stars are sustained only by WIMP annihilations. We determine the observational properties of these “frozen” objects and show that they can be searched for in the local Universe thanks to their anomalous mass-radius relation, which should allow unambiguous discrimination from normal stars.

Based on the previous work in Y. Jiang, Y. M. Shi, H. T. Feng, W. M. Sun, and H. S. Zong, Phys. Rev. C 78, 025214 (2008) on the quark-meson vertex and pion properties at finite quark chemical potential, we provide an analytical analysis of the weak decay constant of the pion ($f_{\pi }[\mu ]$) and the pion mass ($m_{\pi }[\mu ]$) at finite quark chemical potential using the model quark propagator proposed in R. Alkofer, W. Detmold, C. S. Fischer, and P. Maris, Phys. Rev. D 70, 014014 (2004). It is found that when $\mu$ is below a threshold value ${\mu }_0$ (which equals 0.350, 0.377, and 0.341 GeV, for the 2CC, 1R1CC, and 3R parametrizations of the model quark propagator, respectively), $f_{\pi }[\mu ]$ and $m_{\pi }[\mu ]$ are kept unchanged from their vacuum values. The value of ${\mu }_0$ is intimately connected with the pole distribution of the model quark propagator and is found to coincide with the threshold value below which the quark-number density vanishes identically. Numerical calculations show that when $\mu$ becomes larger than ${\mu }_0$, $f_{\pi }[\mu ]$ exhibits a sharp decrease whereas $m_{\pi }[\mu ]$ exhibits a sharp increase. A comparison is given between the results obtained in this paper and those obtained in previous literature.

The relativistic four-quark equations are found in the framework of coupled-channel formalism. The dynamical mixing of the meson-meson states with the four-quark states is considered. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitudes are obtained. The four-quark amplitudes of cryptoexotic mesons including the quarks of three flavours $(u,d,s)$ and the charmed quark are constructed. The poles of these amplitudes determine the masses of tetraquarks. The mass values of low-lying tetraquarks are calculated.

The $\mathrm{SU}(3{)}_L\otimes \mathrm{U}(1{)}_N$ electroweak model predicts new Higgs bosons beyond the one of the standard model. In this work we investigate the signature and production of doubly charged Higgs bosons in the $e^{-}{e}^{+}$ International Linear Collider and in the CERN Linear Collider. We compute the branching ratios for the doubly charged gauge bosons of the model.

We compute the one-loop QCD amplitude for the process $gg\to Q\overline{Q}$ in dimensional regularization through order ${ϵ}^2$ in the dimensional regulator and for arbitrary quark mass values. This result is an ingredient of the next-to-next-to-leading order cross section for heavy-quark production at hadron colliders. The calculation is performed in conventional dimensional regularization using well-known reduction techniques as well as a method based on recent ideas for the functional form of one-loop integrands in four dimensions.