The Higgs-mediated flavor violating bottom-strange quarks transitions induced at the one-loop level by a nondiagonal $Hbs$ coupling are studied within the context of an effective Yukawa sector that comprises $S{U}_L(2)\times U_Y(1)$-invariant operators of up to dimension six. The most recent experimental result on $B\to X_s\gamma$ with hard photons is employed to constrain the $Hbs$ vertex, which is used to estimate the branching ratio for the $B_s\to \gamma \gamma$ decay. It is found that the $B_s\to \gamma \gamma$ decay can reach a branching ratio of the order of $4\times {10}^{-8}$, which is 2 orders of magnitude smaller than the current experimental limit.

We derive an electric current density ${\mathit{j}}_{\mathrm{em}}$ in the presence of a magnetic field $\mathit{B}$ and a chiral chemical potential ${\mu }_5$. We show that ${\mathit{j}}_{\mathrm{em}}$ has, not only the anomaly-induced term $\propto {\mu }_5\mathit{B}$ (i.e. chiral magnetic effect), but also a nonanomalous correction which comes from interaction effects and is expressed in terms of the susceptibility. We find the correction characteristically dependent on the number of quark flavors. The numerically estimated correction turns out to be a minor effect on heavy-ion collisions but can be tested by the lattice-QCD simulation.

We present a class of dynamical solutions in a $D$-dimensional gravitational theory coupled to a dilaton, a form field strength, and a cosmological constant. We find that for any $D$ due to the presence of a cosmological constant, the metric of solutions depends on a quadratic function of the brane world volume coordinates, and the transverse space cannot be Ricci flat except for the case of 1-branes. We then discuss the dynamics of 1-branes in a $D$-dimensional spacetime. For a positive cosmological constant, 1-brane solutions with $D>4$ approach the Milne universe in the far-brane region. On the other hand, for a negative cosmological constant, each 1-brane approaches the others as the time evolves from a positive value, but no brane collision occurs for $D>4$, since the spacetime close to the 1-branes eventually splits into the separate domains. In contrast, the $D=3$ case provides an example of colliding 1-branes. Finally, we discuss the dynamics of 0-branes and show that for $D>2$, they behave like the Milne universe after the infinite cosmic time has passed.

In this paper we investigate wormhole and spherically symmetric solutions in four-dimensional gravity plus a matter source consisting of a ghost scalar field with a sine-Gordon potential. For the wormhole solutions we also include the possibility of electric and/or magnetic charges. For both types of solutions we perform a linear stability analysis and show that the wormhole solutions are stable and that when one turns on the electric and/or magnetic field the solution remains stable. The linear stability analysis of the spherically symmetric solutions indicates that they can be stable or unstable depending on one of the parameters of the system. This result for the spherically symmetric solution is nontrivial since a previous investigation of four-dimensional gravity plus a ghost scalar field with a $\lambda {\varphi }^4$ interaction found only unstable spherically symmetric solutions. Both the wormhole and spherically symmetric solutions presented here asymptotically go to anti-de Sitter space-time.

We construct static codimension-two branes in any odd dimension $D$, with a negative cosmological constant, and show that they are exact solutions of Chern-Simons (super)gravity theory for (super)${\mathrm{AdS}}_D$ coupled to external sources. The stability of these solutions is analyzed by counting the number of preserved supersymmetries. It is shown that static massive ($D-3$)-branes are unstable unless some suitable gauge fields are added and the brane is extremal. In particular, in three dimensions, a 0-brane is recognized as the negative mass counterpart of the Bañados-Teitelboim-Zanelli black hole. For these 0-branes, we write explicitly magnetically charged Bogomol’nyi-Prasad-Sommerfield states with various numbers of preserved supersymmetries within the $OSp(p\mid 2)\times OSp(q\mid 2)$ supergroups. In five dimensions, we prove that stable 2-branes with magnetic charge always exist for the generic supergroup $SU(2,4\mid N)$, where $N\ne 4$. For the special case $N=4$, in which Chern-Simons supergravity requires the addition of a nontrivial gauge field configuration in order to preserve the maximal number of degrees of freedom, we show for two different static 2-branes that they are Bogomol’nyi-Prasad-Sommerfield states (one of which is the ground state), and from the corresponding algebra of charges we show that the energy is bounded from below. In higher dimensions, our results admit a straightforward generalization, although there are presumably more solutions corresponding to different intersections of the elementary objects.

Ivanov pointed out substantial analytical difficulties associated with self-gravitating, static, isotropic fluid spheres when pressure explicitly depends on matter density. Simplifications achieved with the introduction of electric charge were noticed as well. We deal with self-gravitating, charged, anisotropic fluids and get even more flexibility in solving the Einstein-Maxwell equations. In order to discuss analytical solutions we extend Krori and Barua’s method to include pressure anisotropy and linear or nonlinear equations of state. The field equations are reduced to a system of three algebraic equations for the anisotropic pressures as well as matter and electrostatic energy densities. Attention is paid to compact sources characterized by positive matter density and positive radial pressure. Arising solutions satisfy the energy conditions of general relativity. Spheres with vanishing net charge contain fluid elements with unbounded proper charge density located at the fluid-vacuum interface. Notably the electric force acting on these fluid elements is finite, although the acting electric field is zero. Net charges can be huge (${10}^{19}C$) and maximum electric field intensities are very large (${10}^{23}–{10}^{24}\mathrm{statvolt}/\mathrm{cm}$) even in the case of zero net charge. Inward-directed fluid forces caused by pressure anisotropy may allow equilibrium configurations with larger net charges and electric field intensities than those found in studies of charged isotropic fluids. Links of these results with charged strange quark stars as well as models of dark matter including massive charged particles are highlighted. The van der Waals equation of state leading to matter densities constrained by cubic polynomial equations is briefly considered. The fundamental question of stability is left open.

Recent breakthroughs in numerical relativity enable one to examine the validity of the post-Newtonian expansion in the late stages of inspiral. For the comparison between post-Newtonian (PN) expansion and numerical simulations, the waveforms in terms of the spin-weighted spherical harmonics are more useful than the plus and cross polarizations, which are used for data analysis of gravitational waves. Factorized resummed waveforms achieve better agreement with numerical results than the conventional Taylor expanded post-Newtonian waveforms. In this paper, we revisit the post-Newtonian expansion of gravitational waves for a test particle of mass $\mu$ in circular orbit of radius $r_0$ around a Schwarzschild black hole of mass $M$ and derive the spherical harmonic components associated with the gravitational wave polarizations up to order $v^{11}$ beyond Newtonian. Using the more accurate $h_{\ell m}$’s computed in this work, we provide the more complete set of associated ${\rho }_{\ell m}$’s and ${\delta }_{\ell m}$’s that form important bricks in the factorized resummation of waveforms with potential applications for the construction of further improved waveforms for prototypical compact binary sources in the future. We also provide ready-to-use expressions of the 5.5PN gravitational waves polarizations $h_{+}$ and $h_{\times }$ in the test-particle limit for gravitational waves data analysis applications. Additionally, we provide closed analytical expressions for 2.5PN $h_{\ell m}$, 2PN ${\rho }_{\ell m}$, and 3PN ${\delta }_{\ell m}$, for general multipolar orders $\ell$ and $m$ in the test-particle limit. Finally, we also examine the implications of the present analysis for compact binary sources in Laser Interferometer Space Antenna.

The Higgs portal of the standard model provides the opportunity for coupling to a very light scalar field $\varphi$ via the super-renormalizable operator $\varphi (H^{†}H)$. This allows for the existence of a very light scalar dark matter that has coherent interaction with the standard model particles and yet has its mass protected against radiative corrections. We analyze ensuing constraints from the fifth force measurements, along with the cosmological requirements. We find that the detectable level of the fifth force can be achieved in models with low inflationary scales, and by a certain amount of fine-tuning in the initial deviation of $\varphi$ from its minimum.

We study the thermal noise caused by mechanical or thermomechanical dissipation in mirrors of interferometric gravitational wave antennas. We give relative figures of merit for arbitrary Hermite-Gauss or Laguerre-Gauss optical beams regarding the Brownian and thermoelastic noises (substrate and coating) in the infinite mirror approximation.

Comparing the signals measured by the surface and underground scintillator detectors of the Yakutsk Extensive Air Shower Array, we place upper limits on the integral flux and the fraction of primary cosmic-ray photons with energies $E>{10}^{18}\mathrm{eV}$, $E>2\times {10}^{18}\mathrm{eV}$, and $E>4\times {10}^{18}\mathrm{eV}$. The large collected statistics of the showers measured by large-area muon detectors provides a sensitivity to photon fractions $<{10}^{-2}$, thus achieving precision previously unreachable at ultrahigh energies.

In some extensions of the standard model with extended Higgs sectors, events from new particle production may pass the selection criteria for Higgs search in different channels at the LHC—14 TeV and mimic Higgs signals. This intriguing possibility is illustrated by PYTHIA based simulations using several representative points in the parameter space of the minimal supersymmetric standard model (MSSM) including a point in the minimal supergravity model consistent with the dark matter (DM) relic density data. Our simulations explore the interplay between the charged Higgs signal and typical squark-gluino events. We argue that the standard selections like the one based on the polarization properties of the $\tau$’s from charged Higgs decay, though adequate for handling the SM backgrounds, may not be very efficient in the presence of SUSY backgrounds. We then propose an alternative search strategy based on pure kinematics which sufficiently controls both the SM and the MSSM backgrounds. For charged Higgs masses ($H^{\pm }$) in the deep decoupling regime ($600\mathrm{GeV}\lesssim m_{H^{\pm }}\lesssim 800\mathrm{GeV}$) this method works well and extends the LHC reach close to 800 GeV for an integrated luminosity of $30{\mathrm{fb}}^{-1}$ with or without the SUSY background. For a lighter charged Higgs a judicious combination of the old selections and some of the cuts proposed by us may disentangle the Higgs signal from the squark-gluino backgrounds quite effectively.

We investigate the effects of four-fermion interactions on the phase diagram of strongly interacting theories for any representation as function of the number of colors and flavors. We show that the conformal window, for any representation, shrinks with respect to the case in which the four-fermion interactions are neglected. The anomalous dimension of the mass increases beyond the unity value at the lower boundary of the new conformal window. We plot the new phase diagram which can be used, together with the information about the anomalous dimension, to propose ideal models of walking technicolor. We discover that when the extended technicolor sector, responsible for giving masses to the standard model fermions, is sufficiently strongly coupled the technicolor theory, in isolation, must have an infrared fixed point for the full model to be phenomenologically viable. Using the new phase diagram we show that the simplest one family and minimal walking technicolor models are the archetypes of models of dynamical electroweak symmetry breaking. Our predictions can be verified via first principle lattice simulations.

We propose the “supersymmetric (SUSY) Yukawa sum rule,” a relationship between physical masses and mixing angles of the third-generation quarks and squarks. The sum rule follows directly from a relation between quark and squark couplings to the Higgs, enforced by SUSY. It is exactly this relation that ensures the cancellation of the one-loop quadratic divergence in the Higgs mass from the top sector. Testing the sum rule experimentally would thus provide a powerful consistency check on SUSY as the solution to the gauge hierarchy problem. While such a test will most likely have to await a future next-generation lepton collider, the LHC experiments may be able to make significant progress towards this goal. If some of the terms entering the sum rule are measured at the LHC, the sum rule can be used (within SUSY framework) to put interesting constraints on the other terms, such as the mixing angles among third-generation squarks. We outline how the required mass measurements could be performed, and estimate the accuracy that can be achieved at the LHC.

An SU(2) lattice gauge theory with two doublets of complex scalar fields is considered. All continuous symmetries are identified and, using the nonperturbative methods of lattice field theory, the phase diagram is mapped out by direct numerical simulation. Two-doublet models contain phase transitions that separate qualitatively distinct regions of the parameter space. In some regions global symmetries are spontaneously broken. For some special choices of the model parameters, the symmetry-breaking order parameter is calculated. The pattern of symmetry breaking is verified further through observation of Goldstone bosons.

The LHCb experiment at CERN’s Large Hadron Collider will soon allow us to enter a new era in the exploration of $B_s$ decays. A particularly promising channel for the search of “new physics” is $B_s^0\to {\mu }^{+}{\mu }^{-}$. The systematic key uncertainty affecting the measurement of this—and in fact all $B_s$-decay branching ratios—is the ratio of fragmentation functions $f_d/f_s$. As the currently available methods for determining $f_d/f_s$ are not sufficient to meet the high precision at LHCb, we propose a new strategy using ${\overline{B}}_s^0\to D_s^{+}{\pi }^{-}$ and ${\overline{B}}_d^0\to D^{+}{K}^{-}$. It allows us to obtain a lower experimental bound on $\mathrm{BR}(B_s^0\to {\mu }^{+}{\mu }^{-})$ which offers a powerful probe for new physics. In order to go beyond this bound and to determine $f_d/f_s$ with a theoretical precision matching the experimental one it is sufficient to know the $SU(3)$-breaking correction to a form-factor ratio from nonperturbative methods at the level of 20%. Thanks to our strategy, we can detect new physics in $B_s^0\to {\mu }^{+}{\mu }^{-}$ at LHCb with $5\sigma$ for a branching ratio as small as twice the standard model value, which represents an improvement of the new-physics reach by about a factor of 2 with respect to the current LHCb expectation.

The nonlocal vacuum condensates of QCD describe the distributions of quarks and gluons in the nonperturbative QCD vacuum. Physically, this means that vacuum quarks and gluons have nonzero mean squared momentum, called virtuality. In this paper we study the quark virtuality which is given by the ratio of the local quark-gluon mixed vacuum condensate to the quark local vacuum condensate. The two vacuum condensates are obtained by solving Dyson-Schwinger equations of a fully dressed quark propagator with an effective gluon propagator. Using our calculated condensates, we obtain the virtuality of quarks in the QCD vacuum state. Our numerical predictions are consistent with other theoretical model calculations such as QCD sum rules, lattice QCD and instanton models.

In the two-quark model supposition for $f_0(980)$ and $K_0^{*}(1430)$, the branching ratios and the direct $CP$-violating asymmetries for decays ${\overline{B}}^0\to f_0(980){\rho }^0(\omega$, $\varphi )$, $K_0^{*0}(1430){\rho }^0(\omega )$, $K_0^{*-}(1430){\rho }^{+}$ and $B^{-}\to f_0(980){\rho }^{-}$, $K_0^{*0}(1430){\rho }^{-}$, $K_0^{*-}(1430){\rho }^0(\omega )$ are studied by employing the perturbative QCD factorization approach. we find the following results: (a) if the scalar meson $f_0(980)$ is viewed as a mixture of $s\overline{s}$ and $(u\overline{u}+d\overline{d})/\sqrt{2}$, the branching ratios of the $b\to d$ transition processes ${\overline{B}}^0\to f_0(980){\rho }^0(\omega ,\varphi )$ and $B^{-}\to f_0(980){\rho }^{-}$ are smaller than the currently experimental upper limits, and the predictions for the decays ${\overline{B}}^0\to f_0(980)\omega$, $B^{-}\to f_0(980){\rho }^{-}$ are not far away from their limits; (b) in the $b\to s$ transition processes $B\to K_0^{*}(1430)\rho (\omega )$, the branching ratio of ${\overline{B}}^0\to K_0^{*0}(1430){\rho }^0$ is the smallest one, at the order of ${10}^{-7}$ by treating $K_0^{*}(1430)$ as the lowest lying state, about $4.8\times {10}^{-6}$ by considering $K_0^{*}(1430)$ as the first excited state; (c) the direct $CP$-violating asymmetries of decays $B\to f_0(980)\rho (\omega )$ have a strong dependence on the mixing angle $\theta$: they are large in the range of $25°<\theta <40°$, and small in the range of $140°<\theta <165°$, while the direct $CP$-violating asymmetry amplitudes of decays $B\to K_0^{*}(1430)\rho (\omega )$ are not large in the two kinds of state supposition for $K_0^{*}(1430)$ and most of them are less than 20%.

Since the pioneering work of Eichten and Lane it has been known that the scale of the interactions responsible for the generation of the strange-quark mass in extended technicolor theories must, absent any Glashow-Iliopoulos-Maiani mechanism for suppressing flavor-changing neutral currents, be greater than of order 1000 TeV. In this paper we point out that the constraint from the neutral $D$-meson system is now equally strong, implying that the charm quark mass must also arise from flavor dynamics at a scale this high. We then quantify the degree to which the technicolor condensate must be enhanced in order to yield the observed quark masses, if the extended technicolor scale is of order 1000 TeV. Our results are intended to provide a framework in which to interpret and apply the results of lattice studies of conformal strongly interacting gauge theories, and the corresponding numerical measurements of the anomalous dimension of the mass operator in candidate theories of walking technicolor.

The calculation of both spinor and tensor Green’s functions in four-dimensional conformally-invariant field theories can be greatly simplified by six-dimensional methods. For this purpose, four-dimensional fields are constructed as projections of fields on the hypercone in six-dimensional projective space, satisfying certain transversality conditions. In this way some Green’s functions in conformal field theories are shown to have structures more general than those commonly found by use of the inversion operator. These methods fit in well with the assumption of AdS/CFT duality. In particular, it is transparent that if fields on ${\mathrm{AdS}}_5$ approach finite limits on the boundary of ${\mathrm{AdS}}_5$, then in the conformal field theory on this boundary these limits transform with conformal dimensionality zero if they are tensors (of any rank), but with conformal dimension $1/2$ if they are spinors or spinor-tensors.

A detailed analysis of the spherically symmetric isolated horizon system is performed in terms of the connection formulation of general relativity. The system is shown to admit a manifestly $SU(2)$ invariant formulation where the (effective) horizon degrees of freedom are described by an $SU(2)$ Chern-Simons theory. This leads to a more transparent description of the quantum theory in the context of loop quantum gravity and modifications of the form of the horizon entropy.