Using the $SL(2,R)$ duality in a dimensionally reduced spacetime in (the bosonic sector of) five-dimensional minimal supergravity, we construct general Kaluza-Klein black hole solutions which carry six independent charges: its mass, angular momentum along four dimensions, and electric and magnetic charges of the Maxwell fields, in addition to Kaluza-Klein electric and magnetic monopole charges.

A four-dimensional scalar field theory with quartic and of higher-power interactions suffers the triviality issue at the quantum level. This is due to coupling constants that, contrary to the physical expectations, seem to grow without a bound with energy. Since this problem concerns the high- energy domain, interaction with a quantum gravitational field may provide a natural solution to it. In this paper we address this problem considering a scalar field theory with a general analytic potential having ${\mathbb{Z}}_2$ symmetry and interacting with a quantum gravitational field. The dynamics of the latter is governed by the cosmological constant and the Einstein-Hilbert term, both being the lowest and next-to-lowest terms of the effective theory of quantum gravity. Using the Vilkovisky-DeWitt method we calculate the one-loop correction to the scalar field effective action. We also derive the gauge-independent one-loop beta functions for all the scalar field couplings in the minimal subtraction scheme. We find that the leading gravitational corrections act in the direction of asymptotic freedom. Moreover, assuming both the Newton and cosmological constants have nonzero fixed point values, we find asymptotically free Halpern-Huang potentials.

Peaks in two-dimensional weak lensing (WL) maps contain significant cosmological information, complementary to the WL power spectrum. This has recently been demonstrated using N-body simulations which neglect baryonic effects. Here we employ ray-tracing N-body simulations to source galaxies at redshift $z_s=2$ in which we manually steepen the density profile of each dark matter halo, mimicking the cooling and concentration of baryons into dark matter potential wells. We find, in agreement with previous works, that this causes a significant increase in the amplitude of the WL power spectrum on small scales (spherical harmonic index $\ell \gtrsim 1,000$). We then study the impact of the halo concentration increase on the peak counts, and find the following. (i) Low peaks (with convergence $0.02\lesssim {\kappa }_{\mathrm{peak}}\lesssim 0.08$) remain nearly unaffected. These peaks are created by a constellation of several halos with low masses ($\sim {10}^{12}–{10}^{13}{\mathrm{M}}_{\odot }$) and large angular offsets from the peak center ($\gtrsim 0.5R_{\mathrm{vir}}$); as a result, they are insensitive to the central halo density profiles. These peaks contain most of the cosmological information, and thus provide an unusually sensitive and unbiased probe. (ii) The number of high peaks (with convergence ${\kappa }_{\mathrm{peak}}\gtrsim 0.08$) is increased. However, when the baryon effects are neglected in cosmological parameter estimation, then the high peaks lead to a modest bias, comparable to that from the power spectrum on relatively large scales ($\ell <2000$), and much smaller than the bias from the power spectrum on smaller scales ($\ell >2000$). (iii) In the three-dimensional parameter space $({\sigma }_8,{\Omega }_m,w)$, the biases from the high peaks and the power spectra are in different directions. This suggests the possibility of “self-calibration”: the combination of peak counts and power spectrum can simultaneously constrain baryonic physics and cosmological parameters.

A model of unification of dark matter and dark energy based on the modeling of the speed of sound as a function of the parameter of the equation of state is introduced. It is found that the model in which the speed of sound depends on the power of the parameter of the equation of state, $c_s^2=\alpha (-w{)}^{\gamma }$, contains the generalized Chaplygin gas models as its subclass. An effective scalar field description of the model is obtained in a parametric form which in some cases can be translated into a closed form solution for the scalar field potential. A constraint on model parameters is obtained using the observational data on the Hubble parameter at different redshifts.

We revisit the neutral Higgs sector of the Higgs triplet model, with non-negligible mixing in the $CP$-even Higgs sector. We examine the possibility that one of the Higgs boson states is the particle observed at the LHC at 125 GeV, and the other is either the small LEP excess at 98 GeV, or the CMS excess at 136 GeV, or that the neutral Higgs bosons are (almost) degenerate and have both mass 125 GeV. We show that, under general considerations, an (unmixed) neutral Higgs boson cannot have an enhanced decay branching ratio into $\gamma \gamma$ with respect to the Standard Model one. An enhancement is, however, possible for the mixed case but only for the heavier of the two neutral Higgs bosons and not for mass-degenerate Higgs bosons. At the same time the branching ratios into $W{W}^{*}$, $Z{Z}^{*}$, $b\overline{b}$, and ${\tau }^{+}{\tau }^{-}$ are similar to the Standard Model, or reduced. We correlate the branching ratios of both Higgs states into $Z\gamma$ to those into $\gamma \gamma$ for the three scenarios. The mixed neutral sector of the Higgs triplet model exhibits some features that could distinguish it from other scenarios at the LHC.

After the recent discovery of a Standard Model Higgs bosonlike particle at the LHC, the question of its couplings to known and unknown matter is eminent. In this paper, we present a method that allows for an enhancement in signal over background (irreducible) of the order of 100% in $pp\to (h\to \gamma \gamma )jj$ for a center of mass energy of 8 and 14 TeV. This is achieved by applying the matrix element method. We discuss the implications of detector resolution effects and various approximations of the involved event simulation and reconstruction. The matrix element method provides a reliable, stable, and efficient handle to separate signal from background and the gluon and weak boson fusion components involved in this process. Employing this method, a more precise Higgs boson coupling extraction can be obtained, and our results are of immediate relevance for current searches.

In this paper we propose indirect probes of the supersymmetry-breaking scale, through observations in the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). We consider scenarios where the lightest supersymmetric particle is the gravitino, and the next-to-lightest supersymmetric particle (NLSP) is a long-lived slepton. We demonstrate that JEM-EUSO will be able to probe models where the NLSP decays, therefore probing supersymmetry-breaking scales below $5\times {10}^6\mathrm{GeV}$. The observatory field of view will be large enough to detect a few tens of events per year, depending on its energy threshold. This is complementary to a previous proposal [I. Albuquerque et al., Phys. Rev. Lett. 92, 221802 (2004)] where it was shown that $1{\mathrm{km}}^3$ neutrino telescopes can directly probe this scale. NLSPs will be produced by the interaction of high-energy neutrinos in the Earth. Here we investigate scenarios where they subsequently decay, either in the atmosphere after escaping the Earth or right before leaving the Earth, producing taus. These can be detected by JEM-EUSO and have two distinctive signatures: one, they are produced in the Earth and go upwards in the atmosphere, which allows discrimination from atmospheric taus, and second, as NLSPs are always produced in pairs, coincident taus will be a strong signature for these events. Assuming that the neutrino flux is equivalent to the Waxman-Bahcall limit, we determine the rate of taus from NLSP decays reaching JEM-EUSO’s field of view.

The non-Abelian discrete symmetry $D_7$ of the heptagon is successfully applied to both quark and lepton mass matrices, including $CP$ violation.

We consider the vanishing thickness limit of a wall separating Minkowski spacetime from Schwarzschild or Friedmann spacetime with the purpose of obtaining the thin shell described by the Israel matching formalism. We show that the thin shell cannot be a limit of the wall consisting of Lemaitre-Tolman-Bondi dust. To successfully implement the required limit, it is necessary to add anisotropy to the stress tensor of the wall matter. For such anisotropic matter, we derive boundary conditions that allow carrying out the limit. Finally, we provide an example of a solution satisfying these conditions.

Recently, the ATLAS and CMS detectors have discovered a bosonic particle which, to a reasonable degree of statistical uncertainty, fits the profile of the Standard Model Higgs. One obvious implication is that models which predict a significant departure from Standard Model phenomenology, such as large exotic (e.g., invisible) Higgs decay or mixing with a hidden sector scalar, are already ruled out. This observation threatens the viability of electroweak baryogenesis, which favors, for example, a lighter Higgs and a Higgs coupled to or mixed with light scalars. To assess the broad impact of these constraints, we propose a scheme for classifying models of the electroweak phase transition and impose constraints on a class-by-class basis. We find that models, such as the Minimal Supersymmetric Standard Model, which rely on thermal loop effects are severely constrained by the measurement of a 125 GeV Higgs. Models which rely on tree-level effects from a light singlet are also restricted by invisible decay and mixing constraints. Moreover, we find that the parametric region favored by electroweak baryogenesis often coincides with an enhanced symmetry point with a distinctive phenomenological character. In particular, enhancements arising through an approximate continuous symmetry are phenomenologically disfavored, in contrast with enhancements from discrete symmetries. We also comment on the excess of diphoton events observed by ATLAS and CMS. We note that although Higgs portal models can accommodate both enhanced diphoton decay and a strongly first-order electroweak phase transition, the former favors a negative Higgs portal coupling whereas the latter favors a positive one, and therefore these two constraints are at tension with one another.

We show that inclusion of a TeV scale chiral superfield transforming in the adjoint representation of the color SU(3) to the minimal supersymmetric standard model particle content modifies the renormalization group running of some parameters in such a way that a 125 GeV mass of the light Higgs boson is accommodated more comfortably than in the constrained minimal supersymmetric standard model or minimal supergravity. Put differently, the introduction of a color adjoint TeV scale superfield helps resurrect lighter choices for the top squark and gluino which are otherwise disfavored in the constrained minimal supersymmetric standard model or minimal supergravity.

In the Standard Model, there are several canonical examples of pure leptonic processes involving the muon, the electron, and the corresponding neutrinos which are connected by the crossing symmetry: i) the decay of muon $\mu \to e{\nu }_{\mu }{\nu }_e$, ii) the inverse muon decay ${\nu }_{\mu }e\to \mu {\nu }_e$, and iii) the annihilation of a muon and an electron into two neutrinos, $\mu e\to {\nu }_{\mu }{\nu }_e$. Although the first two reactions have been observed and measured since long ago, the third process, resulting in the invisible final state, has never been experimentally tested. It may go either directly, or, at low energies, via the annihilation of a muon and an electron from an atomic bound state, called muonium ($M={\mu }^{+}{e}^{-}$). The $M\to {\nu }_e{\overline{\nu }}_{\mu }$ decay is expected to be a very rare process, with the branching fraction predicted to be $\mathrm{Br}(M\to {\nu }_e{\overline{\nu }}_{\mu })=6.6\times {10}^{-12}$ with respect to the ordinary muon decay rate. Using the reported experimental results on precision measurements of the positive muon lifetime by the MuLan Collaboration, we set the first limit $\mathrm{Br}(M\to \mathrm{\text{invisible}})<5.7\times {10}^{-6}$ (90% C.L.), while still leaving a big gap of about six orders of magnitude between this bound and the predictions. To improve substantially the limit, we proposed to perform an experiment dedicated to the sensitive search for the $M\to \mathrm{\text{invisible}}$ decay. A feasibility study of the experimental setup shows that the sensitivity of the search for this decay mode in branching fraction $\mathrm{Br}(M\to \mathrm{\text{invisible}})$ at the level of ${10}^{-12}$ could be achieved. If the proposed search results in a substantially higher branching fraction than predicted, say $\mathrm{Br}(M\to \mathrm{\text{invisible}})\simeq {10}^{-10}$, this would unambiguously indicate the presence of new physics. We point out that such a possibility may occur due to the muonium transition into a hidden sector and consider, as an example, muonium-mirror muonium conversion in the mirror matter model. A result in agreement with the Standard Model prediction would be a theoretically clean check of the pure leptonic bound state annihilation through the charged current weak interactions, which place constraints for further attempts beyond the Standard Model. We believe our work gives strong motivations to perform the proposed experiment on the search for the invisible decay of muonium in the near future.

We examine a gravitational lens model inspired by modified gravity theories and exotic matter and energy. We study an asymptotically flat, static, and spherically symmetric spacetime that is modified in such a way that the spacetime metric depends on the inverse distance to the power of positive $n$ in the weak-field approximation. It is shown analytically and numerically that there is a lower limit on the source angular displacement from the lens object to get demagnification. Demagnifying gravitational lenses could appear, provided the source position $\beta$ and the power $n$ satisfy $\beta >2/(n+1)$ in the units of the Einstein ring radius under a large-$n$ approximation. Unusually, the total amplification of the lensed images, though they are caused by the gravitational pull, could be less than unity. Therefore, time-symmetric demagnification parts in numerical light curves by gravitational microlensing [F. Abe, Astrophys. J. 725, 787 (2010)] may be evidence of an Ellis wormhole (being an example of traversable wormholes), but they do not always prove it. Such a gravitational demagnification of the light might be used for hunting a clue of exotic matter and energy that are described by an equation of state more general than the Ellis wormhole case. Numerical calculations for the $n=3$ and 10 cases show maximally $\sim 10$ and $\sim 60$ percent depletion of the light, when the source position is $\beta \sim 1.1$ and $\beta \sim 0.7$, respectively.

It is well known that the sum of signed magnifications is invariant for mass lens systems. In this paper, we discuss the signed magnification sums of general spherical lens models, including the singular isothermal sphere, the Schwarzschild lens, and the Ellis wormhole, the last of which is an example of the traversable wormholes of the Morris-Thorne class. We show that the signed magnification sums are a very useful tool to distinguish exotic lens objects. For example, we show that one can distinguish the Ellis wormholes from the Schwarzschild lens with the signed magnification sums.

The near horizon geometry of extremal rotating black hole in arbitrary dimension possesses $SO(2,1)\times U(n)$ symmetry in the special case that all $n$ rotation parameters are equal. We consider a conformal particle associated with such a maximally symmetric configuration and derive from it a new integrable Hamiltonian mechanics with $U(n)$ symmetry. A further reduction of the model is discussed, which is obtained by discarding cyclic variables. A variant of the Higgs oscillator and the Pöschl-Teller system show up in four and five dimensions, respectively.

It is well known that by applying the first law of thermodynamics to the apparent horizon of a Friedmann-Robertson-Walker Universe and, assuming the entropy associated with the apparent horizon has the same form as the entropy formula for the static spherically symmetric black holes, one can derive the corresponding Friedmann equations in Einstein, Gauss-Bonnet, and more general Lovelock gravity. Is this a generic feature of any gravitational theory? Is the prescription applicable to other gravities? In this paper we would like to address the above questions by examining the same procedure for Horava-Lifshitz gravity. We find that in Horava-Lifshitz gravity, this approach does not work and we fail to reproduce a corresponding Friedmann equation in this theory by applying the first law of thermodynamics on the apparent horizon, together with the appropriate expression for the entropy in Horava-Lifshitz gravity. The reason for this failure seems to be due to the fact that Horava-Lifshitz gravity is not diffeomorphism invariant, and thus, the corresponding field equation cannot be derived from the first law around horizon in the spacetime. Without this, it implies that the specific gravitational theory is not consistent, which shows an additional problematic feature of Horava-Lifshitz gravity. Nevertheless, if we still take the area formula of geometric entropy and regard the Horava-Lifshitz sector in the Friedmann equation as an effective dark radiation, we are able to extract the corresponding Friedmann equation from the first law of thermodynamics.

Two different realistic $F(R)$ modified gravity models are considered in the framework of the Friedmann-Lemetre-Robertson-Walker universe. The parameters of these two models are adjusted to reach coherence with the most recent and accurate observations of the current Universe. A study of the growth of matter density perturbations is done, and several parametrizations of the growth index are developed for both models. The ansatz for the growth index given by $\gamma ={\gamma }_0+{\gamma }_{1}z/(1+z)$ seems to be the best parametrization for the two models considered. Finally, the values obtained for ${\gamma }_0$ and ${\gamma }_1$ can be used in order to characterize these two models and to differentiate them from others such as the Hu-Sawicki model.

We present a realization of astronomical relativistic reference frames in the Solar System and its application to the Gravity Recovery and Interior Laboratory (GRAIL) mission. We model the necessary space-time coordinate transformations for light-trip time computations and address some practical aspects of the implementation of the resulting model. We develop all the relevant relativistic coordinate transformations that are needed to describe the motion of the GRAIL spacecraft and to compute all observable quantities. We take into account major relativistic effects contributing to the dual one-way range observable, which is derived from one-way signal travel times between the two GRAIL spacecrafts. We develop a general relativistic model for this fundamental observable of GRAIL, accurate to $1\mu \mathrm{m}$. We develop and present a relativistic model for another key observable of this experiment, the dual one-way range rate, accurate to $1\mu \mathrm{m}/\mathrm{s}$. The presented formulation justifies the basic assumptions behind the design of the GRAIL mission. It may also be used to further improve the already impressive results of this lunar gravity recovery experiment after the mission is complete. Finally, we present transformation rules for frequencies and gravitational potentials and their application to GRAIL.

We reconstruct an f(R) gravity model that gives rise to the particular $\Lambda \mathrm{CDM}$ background evolution of the Universe. We find well-defined, real-valued analytical forms for the f(R) model to describe the Universe both in the early epoch from the radiation to matter dominated eras and the late time acceleration period. We further examine the viability of the derived f(R) model and find that it is viable to describe the evolution of the Universe in the past and the future singularity does not exist in the Lagrangian.

By considering adiabatic contraction of the dark matter (DM) during star formation, we estimate the amount of DM trapped in stars at their birth. If the DM consists partly of primordial black holes (PBHs), they will be trapped together with the rest of the DM and will be finally inherited by a star compact remnant—a white dwarf (WD) or a neutron star (NS), which they will destroy in a short time. Observations of WDs and NSs thus impose constraints on the abundance of PBH. We show that the best constraints come from WDs and NSs in globular clusters which exclude the DM consisting entirely of PBH in the mass range ${10}^{16}-3\times {10}^{22}\mathrm{g}$, with the strongest constraint on the fraction ${\Omega }_{\mathrm{PBH}}/{\Omega }_{\mathrm{DM}}\lesssim {10}^{-2}$ being in the range of PBH masses ${10}^{17}–{10}^{18}\mathrm{g}$.