The purpose of this study is to describe a perfect fluid matter distribution that leads to a constant curvature region, thanks to the effect of a nonminimal coupling. This distribution exhibits a density profile within the range found in the interstellar medium and an adequate matching of the metric components at its boundary. By identifying this constant curvature with the value of the cosmological constant and superimposing the spherical distributions arising from different matter sources throughout the universe, one is able to mimic a large-scale homogeneous cosmological constant solution.

I consider a landscape containing three vacua and study the topology of global spacelike slices in eternal inflation. A discrete toy model, which generalizes the well-studied Mandelbrot model, reveals a rich phase structure. Novel phases include monochromatic tubular phases, which contain crossing curves of only one vacuum, and a democratic tubular phase, which contains crossing curves of all three types of vacua. I discuss the generalization to realistic landscapes consisting of many vacua. Generically, the system ends up in a grainy phase, which contains no crossing curves or surfaces and consists of packed regions of different vacua. Other topological phases arise on the scale of several generations of nucleations.

We investigate the internal structure of charged black holes with a spherically symmetric model in the double-null coordinate system. Hawking radiation is considered using the S-wave approximation of semiclassical backreaction and discharge is simulated by supplying an oppositely charged matter to the black hole. In the stage of formation, the internal structure is determined by the mass and charge of collapsing matter. When the charge-mass ratio is small, a wormhole-like internal structure is observed. The structure becomes analogous to the static limit as the ratio reaches unity. After the formation, mass inflation induces large curvature in the internal structure, which makes the structure insensitive to the late-time perturbations. The internal structure determined from the formation seems to be maintained during a substantial mass reduction. The discharge and neutralization of charged black holes is also investigated for both nonevaporating and evaporating cases. Finally, we discuss the implications of the wormhole-like structure inside of charged black holes.

The general solution of Einstein’s gravity equation in $D$ dimensions for an anisotropic and spherically symmetric matter distribution is calculated in a bulk with a position dependent cosmological constant. Results for $n$ concentric $(D-2)$-branes with arbitrary mass, radius, and pressure with different cosmological constant between branes are found. It is shown how the different cosmological constants contribute to the effective mass of each brane. It is also shown that the equation of state for each brane influences the dynamics of branes, which can be divided into eras according to the dominant matter. This scenario can be used to model the universe in the $D=5$ case, which may present a phenomenology richer than the current models. The evolution law of the branes is studied, and the anisotropic pressure that removes divergences is found. The Randall-Sundrum metric in an outside-the-region in the flat branes limit is also derived.

Self-energies of a minimally coupled scalar field with quartic and trilinear interactions are calculated in a de Sitter background, using a position space propagator. For quartic interactions, we recover earlier results for the seagull diagram, namely, that it contributes an effective mass for the scalar field at leading order in the infrared enhancement in a steady-state de Sitter background. We further show that the sunset diagram also contributes to this effective mass and argue that these two contributions are sufficient in order to determine a self-consistent dynamical mass. In addition, trilinear interactions also induce a dynamical mass for the scalar field which we calculate. Since an interacting scalar field in de Sitter acquires a dynamical mass through these loop corrections, the infrared divergences of the two-point correlator are naturally self-regulated.

The growth rate of matter perturbations is computed in a magnetized environment for the $\Lambda \mathrm{CDM}$ and $w\mathrm{CDM}$ paradigms. It is argued that the baryons do not necessarily follow into the dark matter potential wells after they are released from the drag of the photons. The baryonic evolution equations inherit a forcing term whose explicit form depends on the plasma description and can be deduced, for instance, in the resistive magnetohydrodynamical approximation. After deriving an analytical expression for the growth rate applicable when dark energy does not cluster, the effects of relativistic corrections and of the inhomogeneities associated with the other species of the plasma are taken into account numerically. The spectral amplitudes and slopes of the stochastic magnetic background are selected to avoid appreciable distortions in the measured temperature and polarization anisotropies of the cosmic microwave background. The growth of structures in the current paradigms of structure formation represents a complementary probe of large-scale magnetism in the same way as the shape of the growth factor and the associated indices can be used, in the conventional lore, to discriminate between competing scenarios of dark energy or even to distinguish different models of gravity.

Proof of the Froissart theorem is reconsidered in a different way to extract its necessary conditions. Two physical inputs, unitarity and absence of massless intermediate hadrons, are indisputable. Also important are mathematical properties of the Legendre functions. Assumptions on dispersion relations, single or double, appear to be excessive. Instead, one should make assumptions on possible high-energy asymptotics of the amplitude in nonphysical configurations, which have today no firm basis. Asymptotics for the physical amplitude always appear essentially softer than for the nonphysical one. Froissart’s paper explicitly assumed the hypothesis of power behavior and obtained asymptotic bound for total cross sections $\sim {log}^2(s/s_0)$ with some constant $s_0$. Our bounds are slightly stronger than original Froissart ones. They show that the scale $s_0$ should itself slowly grow with $s$. Under different assumptions about asymptotic behavior of nonphysical amplitudes, the total cross section could grow even faster than ${log}^{2}s$. The problem of correct asymptotics might be clarified by precise measurements at the LHC and higher energies.

Using simple models in $D=0+0$ and $D=0+1$ dimensions we construct partition functions and compute two-point correlations. The exact result is compared with saddle point approximation and solutions of Schwinger-Dyson equations. When integrals are dominated by more than one saddle point we find Schwinger-Dyson equations do not reproduce the correct results unless the action is first transformed into dual variables.

In the absence of low-energy supersymmetry, a multiplicity of weak-scale Higgs doublets would require additional fine-tunings unless they formed an irreducible multiplet of a non-Abelian symmetry. Remnants of such symmetry typically render some Higgs fields stable, giving several dark matter particles of various masses. The non-Abelian symmetry also typically gives simple, testable mass relations.

The asymmetric dark matter scenario is known to give an interesting solution for the cosmic coincidence problem between baryon and dark matter densities. In the scenario, the dark matter asymmetry, which is translated to the dark matter density in the present universe, is transferred from the $B\mathrm{\text{−}}L$ asymmetry generated in the early universe. On the other hand, the generation of the $B\mathrm{\text{−}}L$ asymmetry is simply assumed, though many mechanisms for the generation are expected to be consistent with the scenario. We show that the generation of the asymmetry in the sneutrino inflation scenario works similarly to the asymmetric dark matter scenario, because the nonrenormalizable operator which translates the $B\mathrm{\text{−}}L$ asymmetry to the dark matter asymmetry is naturally obtained by integrating right-handed neutrinos out. As a result, important issues concerning cosmology (inflation, the mass density of dark matter, and the baryon asymmetry of the universe) as well as neutrino masses and mixing have a unified origin, namely, the right-handed neutrinos.

We study the octet baryon electromagnetic properties by applying the covariant spectator quark model, and provide covariant parametrization that can be used to study baryon electromagnetic reactions. While we use the lattice QCD data in the large pion mass regime (small pion cloud effects) to determine the parameters of the model in the valence quark sector, we use the nucleon physical and octet baryon magnetic moment data to parametrize the pion cloud contributions. The valence quark contributions for the octet baryon electromagnetic form factors are estimated by extrapolating the lattice parametrization in the large pion mass regime to the physical regime. As for the pion cloud contributions, we parametrize them in a covariant, phenomenological manner, combined with SU(3) symmetry. We also discuss the impact of the pion cloud effects on the octet baryon electromagnetic form factors and their radii.

We investigate the critical scaling of the quark propagator of $N_f=2$ QCD close to the chiral phase transition at finite temperature. We argue that it is mandatory to take into account the backreaction effects of pions and the sigma onto the quark to observe critical behavior beyond mean field. On the condition of self-consistency of the quark Dyson-Schwinger equation we extract the scaling behavior for the quark propagator analytically. Crucial in this respect is the correct pion dispersion relation when the critical temperature is approached from below. Our results are consistent with the known relations for the quark condensate and the pion decay constant from universality. We verify the analytical findings also numerically assuming the critical dispersion relation for the Goldstone bosons.

In the framework of $k_t$-factorization approach, we consider the production of $J/\psi$ pairs at the LHC conditions. We give predictions on the differential cross sections and discuss the source and the size of theoretical uncertainties. We also present a comparison with collinear parton model showing a dramatic difference in the $J/\psi$ transverse momentum spectrum and $J/\psi -J/\psi$ azimuthal correlations. Finally, we give predictions on the polarization observables in the helicity and Collins-Soper systems.

We consider an electroweak model based on the gauge symmetry $SU(2{)}_L\otimes U(1{)}_{Y^{\prime }}\otimes U(1{)}_{B-L}$ which has right-handed neutrinos with different exotic $B-L$ quantum numbers. Because of this particular feature we are able to write Yukawa terms, and right-handed neutrino mass terms, with scalar fields that can develop vacuum expectation values belonging to different energy scales. We make a detailed study of the scalar and the Yukawa neutrino sectors to show that this model is compatible with the observed solar and atmospheric neutrino mass scales and the tribimaximal mixing matrix. We also show that there are dark matter candidates if a $Z_2$ symmetry is included.

We present an updated measurement of the anomalous like-sign dimuon charge asymmetry $A_{\mathrm{sl}}^b$ for semileptonic $b$-hadron decays in $9.0{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collisions recorded with the D0 detector at a center-of-mass energy of $\sqrt{s}=1.96\mathrm{TeV}$ at the Fermilab Tevatron collider. We obtain $A_{\mathrm{sl}}^b=(-0.787\pm 0.172(\mathrm{stat})\pm 0.093(\mathrm{syst}))\%$. This result differs by 3.9 standard deviations from the prediction of the standard model and provides evidence for anomalously large $CP$ violation in semileptonic neutral $B$ decay. The dependence of the asymmetry on the muon impact parameter is consistent with the hypothesis that it originates from semileptonic $b$-hadron decays.

Field theories on the Groenewold-Moyal plane are studied using the Lehmann-Symanzik-Zimmermann formalism. The example of real scalar fields is treated in detail. The $S$-matrix elements in this nonperturbative approach are shown to be equal to the interaction representation $S$-matrix elements. This is a new nontrivial result: in both cases, the $S$-operator is independent of the noncommutative deformation parameter ${\theta }_{\mu \nu }$ and the change in scattering amplitudes due to noncommutativity is just a time delay. This result is verified in two different ways. But the off-shell Green’s functions do depend on ${\theta }_{\mu \nu }$. In the course of this analysis, unitarity of the nonperturbative $S$-matrix is proved as well.

This paper is motivated by prospects for non-Abelian statistics of deconfined particlelike objects in $3+1$ dimensions, realized as solitons with localized Majorana zero modes. To this end, we study the fermionic collective coordinates of magnetic monopoles in $3+1$-dimensional spontaneously-broken SU(2) gauge theories with various spectra of fermions. We argue that a single Majorana zero mode of the monopole is not compatible with cancellation of the Witten SU(2) anomaly. We also compare this approach with other attempts to realize deconfined non-Abelian objects in $3+1$ dimensions.

Recently, a low-energy effective theory on non-Abelian semilocal vortices in $\mathcal{N}=2$ supersymmetric quantum chromodynamics with the $\mathrm{U}(N)$ gauge group and $N+\tilde{N}$ quark flavors was obtained in field theory [M. Shifman, W. Vinci, and A. Yung, Phys. Rev. D 83, 125017 (2011).]. The result is exact in a certain limit of large infrared cutoff. The resulting model was called the $zn$ model. We study quantum dynamics of the $zn$ model in some detail. First, we solve it at large $N$ in the leading order. Then we compare our results with those of Hanany and Tong [A. Hanany and D. Tong, J. High Energy Phys. 04 (2004) 066.] (the Hanany-Tong model) who based their derivation on a certain type-IIA formalism, rather than on a field-theory construction. In the ’t Hooft limit of infinite $N$, both models’ predictions are identical. At finite $N$, our calculations agree with the Hanany-Tong results only in the Bogomol’nyi-Prasad-Sommerfeld monopoles sector. Beyond the Bogomol’nyi-Prasad-Sommerfeld monopoles sector, there is no agreement between the $zn$ and Hanany-Tong models. Finally, we study perturbation theory of the $zn$ model from various standpoints.

We study the merger of black hole-neutron star binaries with a variety of black hole spins aligned or antialigned with the orbital angular momentum, and with the mass ratio in the range $M_{\mathrm{BH}}/M_{\mathrm{NS}}=2–5$, where $M_{\mathrm{BH}}$ and $M_{\mathrm{NS}}$ are the mass of the black hole and neutron star, respectively. We model neutron-star matter by systematically parametrized piecewise polytropic equations of state. The initial condition is computed in the puncture framework adopting an isolated horizon framework to estimate the black hole spin and assuming an irrotational velocity field for the fluid inside the neutron star. Dynamical simulations are performed in full general relativity by an adaptive-mesh refinement code, SACRA. The treatment of hydrodynamic equations and estimation of the disk mass are improved. We find that the neutron star is tidally disrupted irrespective of the mass ratio when the black hole has a moderately large prograde spin, whereas only binaries with low mass ratios, $M_{\mathrm{BH}}/M_{\mathrm{NS}}\lesssim 3$, or small compactnesses of the neutron stars bring the tidal disruption when the black hole spin is zero or retrograde. The mass of the remnant disk is accordingly large as $\gtrsim 0.1M_{\odot }$, which is required by central engines of short gamma-ray bursts, if the black hole spin is prograde. Information of the tidal disruption is reflected in a clear relation between the compactness of the neutron star and an appropriately defined “cutoff frequency” in the gravitational-wave spectrum, above which the spectrum damps exponentially. We find that the tidal disruption of the neutron star and excitation of the quasinormal mode of the remnant black hole occur in a compatible manner in high mass-ratio binaries with the prograde black hole spin. The correlation between the compactness and the cutoff frequency still holds for such cases. It is also suggested by extrapolation that the merger of an extremely spinning black hole and an irrotational neutron star binary does not lead to the formation of an overspinning black hole.