I consider models with nonuniversal gaugino masses at the gauge coupling unification scale, taking into account the Higgs boson discovery. Viable regions of parameter space are mapped and studied in the case of nonuniversality following from an $F$-term in a linear combination of singlet and adjoint representations of $SU(5)$. I consider, in particular, “seminatural” models that have small $\mu$, with gaugino masses dominating the supersymmetry-breaking terms at high energies. Higgsino-like particles are then much lighter than all other superpartners, and the prospects for discovery at the Large Hadron Collider can be extremely challenging.

A global study of the negative parity nonstrange baryon observables is performed in the framework of the $1/N_c$ expansion. Masses, partial decay widths and photo couplings are simultaneously analyzed. A main objective is to determine the composition of the spin $\frac{1}{2}$ and $\frac{3}{2}$ nucleon states, which come in pairs and involve two mixing angles which can be determined and tested for consistency by the mentioned observables. The issue of the assignment of those nucleon states to the broken $SU(4)\times O(3)$ mixed-symmetry multiplet is studied in detail, with the conclusion that the assignment made in the old studies based on the nonrelativistic quark model is the preferred one. In addition, the analysis involves an update of the input data with respect to previous works.

We calculate the full two-loop electroweak matching corrections to the operator governing the decay $B_q\to {\ell }^{+}{\ell }^{-}$ in the standard model. Their inclusion removes an electroweak scheme and scale uncertainty of about $\pm 7\%$ of the branching ratio. Using different renormalization schemes of the involved electroweak parameters, we estimate residual perturbative electroweak and QED uncertainties to be less than $\pm 1\%$ at the level of the branching ratio.

Using $580{\mathrm{pb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data taken with the CLEO–c detector at $\psi (3770)$, the decay $D^0({\overline{D}}^0)\to K^{\pm }{\pi }^{\mp }{\pi }^{+}{\pi }^{-}$ has been studied to make the highest precision measurement of $D^0$ mass, $M(D^0)=1864.845\pm 0.025\pm 0.022\pm 0.053\mathrm{MeV}$, where the first error is statistical, the second error is systematic, and the third error is due to uncertainty in kaon masses. As an intermediate step of the present investigation, the mass of the $K_S$ meson has been measured to be $M(K_S)=497.607\pm 0.007\pm 0.015\mathrm{MeV}$. Both $M(D^0)$ and $M(K_S)$ are the most precise single measurements of the masses of these mesons.

In this paper, we use entanglement entropy as a tool to explore the universal properties of conformal field theories (CFTs) dual to extremal BTZ black holes. We demonstrate that the entanglement entropies computed in the CFTs at the boundary of the extremal BTZ and the boundary of the near-horizon limit of the extremal BTZ are in perfect agreement and have the form appropriate to a two-dimensional CFT with only the chiral part excited and the antichiral in the ground state. Furthermore, we analyze the universal limits of the entanglement entropy and recover the correct value of the thermal entropy for large entangling intervals and the first-law-like relation for the small interval.

We study the functional renormalization group flow of a Higgs-Yukawa toy model mimicking the top-Higgs sector of the standard model. This approach allows for treating arbitrary bare couplings. For the class of standard bare potentials of ${\varphi }^4$ type at a given ultraviolet cutoff, we show that a finite infrared Higgs mass range emerges naturally from the renormalization group flow itself. Higgs masses outside the resulting bounds cannot be connected to any conceivable set of bare parameters in this standard model ${\varphi }^4$ class. By contrast, more general bare potentials allow us to diminish the lower bound considerably. We identify a simple renormalization group mechanism for this depletion of the lower bound. If this depletion is also active in the full standard model, Higgs masses smaller than the conventional infrared window do not necessarily require new physics at low scales or give rise to instability problems.

We study the thermodynamics of helium at densities relevant for white dwarf physics. We find evidence that, as the temperature is increased, there is first a first-order transition between two superconducting phases followed by a second-order transition to the normal state. These transitions occur, for realistic densities, at temperatures below the crystallization temperature, and the crystalline state is likely to remain as the true ground state of the system. The calculations are performed with a screening but nondynamical electron background, and we comment on the impact of this and other approximations to our result.

Green and Wald have presented a mathematically rigorous framework to study, within general relativity, the effect of small-scale inhomogeneities on the global structure of space-time. The framework relies on the existence of a one-parameter family of metrics that approaches the effective background metric in a certain way. Although it is not necessary to know this family in an exact form to predict properties of the backreaction effect, it would be instructive to find explicit examples. In this paper, we provide the first example of such a family of exact nonvacuum solutions to the Einstein equations. It belongs to the Wainwright-Marshman class and satisfies all of the assumptions of the Green-Wald framework.

We investigate the robustness of singularity avoidance mechanisms in nonrelativistic quantum mechanics on the discretized real line when lattice points are allowed to approach a singularity of the classical potential. We consider the attractive Coulomb potential and the attractive scale-invariant potential, on an equispaced parity-noninvariant lattice and on a nonequispaced parity-invariant lattice, and we examine the energy eigenvalues by a combination of analytic and numerical techniques. While the lowest one or two eigenvalues descend to negative infinity in the singular limit, we find that the higher eigenvalues remain finite and form degenerate pairs, close to the eigenvalues of a theory in which a lattice point at the singularity is regularized either by Thiemann’s loop quantum gravity singularity-avoidance prescription or by a restriction to the odd-parity sector. The approach to degeneracy can be reproduced from a nonsingular discretized half-line quantum theory by tuning a boundary condition parameter. The results show that Thiemann’s singularity-avoidance prescription and the discretized half-line boundary condition reproduce quantitatively correct features of the singular limit spectrum apart from the lowest few eigenvalues.

We use the conditional symmetry approach to study the $r$ evolution of a minisuperspace spherically symmetric model both at the classical and the quantum level. After integration of the coordinates $t$, $\theta$ and $\varphi$ in the gravitational plus electromagnetic action the configuration space dependent dynamical variables turn out to correspond to the $r$-dependent metric functions and the electrostatic field. In the context of the formalism for constrained systems (Dirac-Bergmann, Arnowitt-Deser-Misner) with respect to the radial coordinate $r$, we set up a pointlike reparametrization invariant Lagrangian. It is seen that, in the constant potential parametrization of the lapse, the corresponding minisuperspace is a Lorentzian three-dimensional flat manifold which obviously admits six Killing vector fields plus a homothetic one. The weakly vanishing $r$ Hamiltonian guarantees that the phase space quantities associated to the six Killing fields are linear holonomic integrals of motion. The homothetic field provides one more rheonomic integral of motion. These seven integrals are shown to comprise the entire classical solution space, i.e. the space-time of a Reissner-Nordström black hole, the $r$-reparametrization invariance since one dependent variable remains unfixed, and the two quadratic relations satisfied by the integration constants. We then quantize the model using as supplementary conditions acting on the wave function, the quantum analogues of the various subalgebras of the classical conditional symmetries. We find that, as a semiclassical analysis shows, in all but one allowed case the ensuing solutions to the Wheeler-DeWitt equation exhibit a good correlation with the classical regime. In the remaining case, the emerging semiclassical geometry is a four-dimensional homogeneous space-time, thus exhibiting no curvature singularity.

The extension of the adiabatic regularization method to spin-$1/2$ fields requires a self-consistent adiabatic expansion of the field modes. We provide here the details of such expansion, which differs from the WKB ansatz that works well for scalars, to firmly establish the generalization of the adiabatic renormalization scheme to spin-$1/2$ fields. We focus on the computation of particle production in de Sitter spacetime and obtain an analytic expression of the renormalized stress-energy tensor for Dirac fermions.

The thermodynamics of a magnetized Kerr-Newman black hole is studied to all orders in the appended magnetic field $B$. The asymptotic properties of the metric and other fields are dominated by the magnetic flux that extends to infinity along the axis, leading to subtleties in the calculation of conserved quantities such as the angular momentum and the mass. We present a detailed discussion of the implementation of a Wald-type procedure to calculate the angular momentum, showing how ambiguities that are absent in the usual asymptotically flat case may be resolved by the requirement of gauge invariance. We also present a formalism from which we are able to obtain an expression for the mass of the magnetized black holes. The expressions for the mass and the angular momentum are shown to be compatible with the first law of thermodynamics and a Smarr-type relation. Allowing the appended magnetic field $B$ to vary results in an extra term in the first law of the form $-\mu dB$ where $\mu$ is interpreted as an induced magnetic moment. Minimizing the total energy with respect to the total charge $Q$ at fixed values of the angular momentum and energy of the seed metric allows an investigation of Wald’s process. The Meissner effect is shown to hold for electrically neutral extreme black holes. We also present a derivation of the angular momentum for black holes in the four-dimensional STU model, which is $\mathcal{N}=2$ supergravity coupled to three vector multiplets.

We study the gravitational collapse of a homogeneous scalar field, minimally coupled to gravity, in the presence of a particular type of dynamical deformation between the canonical momenta of the scale factor and of the scalar field. In the absence of such a deformation, a class of solutions can be found in the literature [R. Goswami and P. S. Joshi], whereby a curvature singularity occurs at the collapse end state, which can be either hidden behind a horizon or be visible to external observers. However, when the phase space is deformed, as implemented herein this paper, we find that the singularity may be either removed or instead, attained faster. More precisely, for negative values of the deformation parameter, we identify the emergence of a negative pressure term, which slows down the collapse so that the singularity is replaced with a bounce. In this respect, the formation of a dynamical horizon can be avoided depending on the suitable choice of the boundary surface of the star. Whereas for positive values, the pressure that originates from the deformation effects assists the collapse toward the singularity formation. In this case, since the collapse speed is unbounded, the condition on the horizon formation is always satisfied and furthermore the dynamical horizon develops earlier than when the phase-space deformations are absent. These results are obtained by means of a thoroughly numerical discussion.

We construct a theory that admits a time-dependent solution smoothly interpolating between a null energy condition (NEC)-satisfying phase at early times and a NEC-violating phase at late times. We first review earlier attempts to violate the NEC and an argument of Rubakov, presented in [V. A. Rubakov, Phys. Rev. D 88, 044015 (2013)], which forbids the existence of such interpolating solutions in a single-field dilation-invariant theory. We then construct a theory which, in addition to possessing a Poincaré-invariant vacuum, does admit such a solution. For a wide range of parameters, perturbations around this solution are at all times stable, comfortably subluminal and weakly coupled. The theory requires us to explicitly break dilation invariance, so it is unlikely that the theory is fully stable under quantum corrections, but we argue that the existence of a healthy interpolating solution is quantum-mechanically robust.

An exact and regular solution describing a couple of charged and spinning black holes is generated in an external electromagnetic field, via the Ernst technique, in Einstein-Maxwell gravity. A wormhole instantonic solution interpolating between the two black holes is constructed to discuss, at the semiclassical level, the quantum process of creation rate, in an external magnetic field, of this charged and spinning black hole pair.

We present the first calculation of an intrinsically relativistic quantity, the leading-order correction to Newtonian theory, in fully nonlinear cosmological large-scale structure studies. Traditionally, nonlinear structure formation in standard $\mathrm{\Lambda }\text{CDM}$ cosmology is studied using N-body simulations, based on Newtonian gravitational dynamics on an expanding background. When one derives the Newtonian regime in a way that is a consistent approximation to the Einstein equations, the first relativistic correction to the usual Newtonian scalar potential is a gravitomagnetic vector potential, giving rise to frame dragging. At leading order, this vector potential does not affect the matter dynamics, thus it can be computed from Newtonian N-body simulations. We explain how we compute the vector potential from simulations in $\mathrm{\Lambda }\text{CDM}$ and examine its magnitude relative to the scalar potential, finding that the power spectrum of the vector potential is of the order ${10}^{-5}$ times the scalar power spectrum over the range of nonlinear scales we consider. On these scales the vector potential is up to two orders of magnitudes larger than the value predicted by second-order perturbation theory extrapolated to the same scales. We also discuss some possible observable effects and future developments.

We constrain several models of the early Universe that predict a statistical anisotropy of the cosmic microwave background (CMB) sky. We make use of WMAP9 maps deconvolved with beam asymmetries. As compared to previous releases of WMAP data, they do not exhibit the anomalously large quadrupole of statistical anisotropy. This allows us to strengthen the limits on the parameters of models established earlier in the literature. In particular, the amplitude of the special quadrupole is constrained as $|g_{*}|<0.072$ at 95% C.L. ($-0.046<g_{*}<0.048$ at 68% C.L.) independently of the preferred direction in the sky. The upper limit is obtained on the total number of $e$-folds in anisotropic inflation with the Maxwellian term nonminimally coupled to the inflaton, namely $N_{\text{tot}}<N_{\mathrm{CMB}}+82$ at 95% C.L. ($+14$ at 68% C.L.) for $N_{\mathrm{CMB}}=60$. We also constrain models of the (pseudo)conformal universe. The strongest constraint is obtained for spectator scenarios involving a long stage of subhorizon evolution after conformal rolling, which reads $h^2<0.006$ at 95% C.L., in terms of the relevant parameter. The analogous constraint is much weaker in dynamical models, e.g., Galilean genesis.

In recent years, cross correlation of lensing of the cosmic microwave background (CMB) with other large-scale structure (LSS) tracers has been used as a method to detect CMB lensing. Current experiments are also becoming sensitive enough to measure CMB lensing without the help of auxiliary tracers. As data quality improves rapidly, it has been suggested that the CMB lensing–LSS cross correlation may provide new insights into parameters describing cosmological structure growth. In this work, we perform forecasts that combine the lensing potential auto power spectrum from various future CMB experiments with the galaxy power spectrum from galaxy surveys, as well as the cross power spectrum between the two, marginalizing over a number of galactic and nongalactic cosmological parameters. We find that the CMB lensing–LSS cross correlation contains significant information on parameters such as the redshift distribution and bias of LSS tracers. We also find that the cross-correlation information will lead to independent probes of cosmological parameters such as neutrino mass and the reionization optical depth.

We show how to lift a generic non-scale-invariant action in Einstein frame into a locally conformally invariant (or Weyl-invariant) theory and present a new general form for Lagrangians consistent with Weyl symmetry. Advantages of such a conformally invariant formulation of particle physics and gravity include the possibility of constructing geodesically complete cosmologies. We present a conformal-invariant version of the standard model coupled to gravity, and show how Weyl symmetry may be used to obtain unprecedented analytic control over its cosmological solutions. Within this new framework, generic Friedmann-Robertson-Walker cosmologies are geodesically complete through a series of big crunch–big bang transitions. We discuss a new scenario of cosmic evolution driven by the Higgs field in a “minimal” conformal standard model, in which there is no new physics beyond the standard model at low energies, and the current Higgs vacuum is metastable as indicated by the latest LHC data.

There has been renewed interest in the possibility that dark matter exists in the form of atoms, analogous to those of the visible world. An important input for understanding the cosmological consequences of dark atoms is their self-scattering. Making use of results from atomic physics for the potentials between hydrogen atoms, we compute the low-energy elastic scattering cross sections for dark atoms. We find an intricate dependence upon the ratio of the dark proton to the dark electron mass, allowing for the possibility to “design” low-energy features in the cross section. Dependences upon other parameters, namely the gauge coupling and reduced mass, scale out of the problem by using atomic units. We derive constraints on the parameter space of dark atoms by demanding that their scattering cross section not exceed bounds from dark matter halo shapes. We discuss the formation of molecular dark hydrogen in the Universe and determine the analogous constraints on the model when the dark matter is predominantly in molecular form.