In both scotogenic neutrino and flavor dark matter models, the dark sector communicates with the standard model fermions via Yukawa portal couplings. We propose an economic scenario where the scotogenic neutrino and a flavored mediator share the same inert Higgs doublet and all are charged under a hidden gauged $U(1)$ symmetry. The dark $Z_2$ symmetry in the dark sector is regarded as the remnant of this hidden $U(1)$ symmetry breaking. In particular, we investigate a dark $U(1{)}_D$ [and also $U(1{)}_{B\text{−}L}$] model which unifies the scotogenic neutrino and top-flavored mediator. Thus dark tops and dark neutrinos are the standard model fermion partners, and the dark matter could be the inert Higgs or the lightest dark neutrino. We note that this model has rich collider signatures on dark tops, the inert Higgs and the $Z^{\prime }$ gauge boson. Moreover, the scalar associated to the $U(1{)}_D$ [and also $U(1{)}_{B\text{−}L}$] symmetry breaking could explain the 750 GeV diphoton excess reported by ATLAS and CMS recently.

Neutrino-nucleus elastic scattering provides a unique laboratory to study the quantum mechanical coherency effects in electroweak interactions, towards which several experimental programs are being actively pursued. We report results of our quantitative studies on the transitions towards decoherency. A parameter ($\alpha$) is identified to describe the degree of coherency, and its variations with incoming neutrino energy, detector threshold, and target nucleus are studied. The ranges of $\alpha$ that can be probed with realistic neutrino experiments are derived, indicating complementarity between projects with different sources and targets. Uncertainties in nuclear physics and in $\alpha$ would constrain sensitivities in probing physics beyond the standard model. The maximum neutrino energies corresponding to $\alpha >0.95$ are derived.

Using the type II seesaw approach and properties of discrete flavor symmetry group representations, we build a supersymmetric $A_4\times A_3$ neutrino model with ${\theta }_{13}\ne 0$. After describing the basis of this model—which is beyond the minimal supersymmetric Standard Model—with a superfield spectrum containing flavons in $A_4\times A_3$ representations, we first generate the tribimaximal neutrino mixing which is known to be in agreement with the mixing angles ${\theta }_{12}$ and ${\theta }_{23}$. Then, we give the scalar potential of the theory where the $A_3$ discrete subsymmetry is used to avoid the so-called sequestering problem. We next study the deviation from the tribimaximal mixing matrix which is produced by perturbing the neutrino mass matrix with a nontrivial $A_4$ singlet. Normal and inverted mass hierarchies are discussed numerically. We also study the breaking of $A_4$ down to $Z_3$ in the charged lepton sector, and use the branching ratio of the decay $\tau \to \mu \mu e$—which is allowed by the residual symmetry $Z_3$—to get estimations on the mass of one of the flavons and the cutoff scale $\mathrm{\Lambda }$ of the model. Key words: Neutrino family symmetry, supersymmetry, deviation from TBM

Generalizing the first law of thermodynamics, the increase in entropy density $\delta S(x)$ of a conformal field theory (CFT) is proportional to the increase in energy density, $\delta E(x)$, of a subsystem divided by a spatially dependent entanglement temperature, $T_E(x)$, a fixed parameter determined by the geometry of the subsystem, crossing over to thermodynamic temperature at high temperatures. In this paper we derive a generalization of the thermodynamic Clausius relation, showing that deformations of the CFT by marginal operators are associated with spatial temperature variations, $\delta T_E(x)$, and spatial energy correlations play the role of specific heat. Using AdS/CFT duality we develop a relationship between a perturbation in the local entanglement temperature of the CFT and the perturbation of the bulk AdS metric. In two dimensions, we demonstrate a method through which direct diagonalizations of the boundary quantum theory may be used to construct geometric perturbations of ${\mathrm{AdS}}_3$.

We consider the quantum mechanics of Calogero models in an oscillator or Coulomb potential on the $N$-dimensional sphere. Their Hamiltonians are obtained by an appropriate Dunkl deformation of the oscillator/Coulomb system on the sphere and its restriction to (Coxeter reflection) symmetric wave functions. By the same method we also find the symmetry generators and compute their algebras.

We construct the Hamiltonians and symmetry generators of Calogero-oscillator and Calogero-Coulomb models on the $N$-dimensional sphere within the matrix-model reduction approach. Our method also produces the integrable Calogero-Coulomb-Stark model on the sphere and proves the integrability of the spin extensions of all these systems.

We investigate the Einstein static universe (ESU) and the emergent universe scenario in the framework of Hořava-Lifshitz-like $F(R)$ gravity. We first perform a dynamical analysis in the phase space, and amongst others we show that a spatially open universe filled with matter satisfying the strong energy condition can exhibit a stable static phase. Additionally, we examine the behavior of the scenario under scalar perturbations and extract the conditions under which it is free of perturbative instabilities, showing that the obtained background ESU solutions are free of such instabilities. However, in order for the Einstein static universe to give rise to the emergent universe scenario we need to have an exotic matter sector that can lead the universe to depart from the stable static state and enter into its usual expanding thermal history.

A new scenario for gravitational collapse has been recently proposed by Haggard and Rovelli. Presenting the model under the name of black hole fireworks, they claim that the accumulation of quantum gravitational effects outside the horizon can cause the tunneling of geometry from a black hole to a white hole, allowing a bounce of the collapsing star which can eventually go back to infinity. In this paper, we discuss the instabilities of this model and propose a simple minimal modification which eliminates them, as well as other related instabilities discussed in the literature. The new scenario is a time-asymmetric version of the original model with a time scale for the final explosion that is shorter than $m\log m$ in Planck units. Our analysis highlights the importance of irreversibility in gravitational collapse which, in turn, uncovers important issues that cannot be addressed in detail without a full quantum gravity treatment.

We study scalar, electromagnetic, axial, and polar gravitational perturbations of the four-dimensional Reissner-Nordström-like black holes with a tidal charge in the Randall-Sundrum braneworld in the first approximation when the tidal perturbations are not taken into account. The quasinormal modes of these perturbations have been studied in both normal and eikonal regimes. Calculations have shown that the black holes on the Randall-Sundrum brane are stable against all kinds of perturbations. Moreover, we determine the greybody factor, giving transmission and reflection of the scattered waves through the effective potentials. It has been shown that the scalar perturbative fields are the most favorite to reflect the wave as compared to the other fields. With increasing value of the tidal charge, the ability of the all perturbative potentials to reflect the waves decreases. Our calculations in low- and high-frequency regimes have shown that black holes on the braneworld always have a bigger absorption cross section of massless scalar waves than the Schwarzschild and standard Reissner-Nordström black holes.

In this paper, we present a spectral decomposition of solutions to relativistic wave equations described on horizon-penetrating hyperboloidal slices within a given Schwarzschild-black-hole background. The wave equation in question is Laplace transformed, which leads to a spatial differential equation with a complex parameter. For initial data which are analytic with respect to a compactified spatial coordinate, this equation is treated with the help of the Mathematica package in terms of a sophisticated Taylor series analysis. Thereby, all ingredients of the desired spectral decomposition arise explicitly to arbitrarily prescribed accuracy, including quasinormal modes and quasinormal mode amplitudes as well as the jump of the Laplace transform along the branch cut. Finally, all contributions are put together to obtain, via the inverse Laplace transformation, the spectral decomposition in question. The paper explains extensively this procedure and includes detailed discussions of relevant aspects, such as the definition of quasinormal modes and the question regarding the contribution of infinity frequency modes to the early time response of the black hole.

In De Rham-Gabadadze-Tolley massive gravity, to get the equations of motion, the square root tensor is assumed to be invertible in the variation of the action. However, this condition cannot be fulfilled when the reference metric is degenerate. This implies that the resulting equations of motion might be different from the case where the reference metric has full rank. In this paper, by generalizing the Moore-Penrose inverse to the cases of symmetric tensors on Lorentz manifolds, we get the equations of motion of the theory with a degenerate reference metric. It is found that the equations of motion are a little bit different from those in the nondegenerate cases. Based on the result of the equations of motion, for the ($2+n$)-dimensional solutions with the symmetry of $n$-dimensional maximally symmetric space, we prove a generalized Birkhoff-type theorem in the case where the degenerate reference metric has rank $n$; i.e., we show that the solutions must be Schwarzschild type or Nariai-Bertotti-Robinson type under the given assumptions.

In this work, we consider wormhole geometries in third-order Lovelock gravity and investigate the possibility that these solutions satisfy the energy conditions. In this framework, by applying a specific equation of state, we obtain exact wormhole solutions, and by imposing suitable values for the parameters of the theory, we find that these geometries satisfy the weak energy condition in the vicinity of the throat, due to the presence of higher-order curvature terms. Finally, we trace out a numerical analysis, by assuming a specific redshift function, and find asymptotically flat solutions that satisfy the weak energy condition throughout the spacetime.

We study the degree to which the cosmic microwave background (CMB) can be used to constrain primordial non-Gaussianity involving one tensor and two scalar fluctuations, focusing on the correlation of one polarization $B$ mode with two temperature modes. In the simplest models of inflation, the tensor-scalar-scalar primordial bispectrum is nonvanishing and is of the same order in slow-roll parameters as the scalar-scalar-scalar bispectrum. We calculate the $⟨BTT⟩$ correlation arising from a primordial tensor-scalar-scalar bispectrum, and show that constraints from an experiment like CMB-Stage IV using this observable are more than an order of magnitude better than those on the same primordial coupling obtained from temperature measurements alone. We argue that $B$-mode non-Gaussianity opens up an as-yet-unexplored window into the early Universe, demonstrating that significant information on primordial physics remains to be harvested from CMB anisotropies.

We reinvestigate the effect of annihilations on the distribution of collisionless dark matter (DM) in a spherical density spike around a massive black hole. We first construct a very simple, pedagogic, analytic model for an isotropic phase space distribution function that accounts for annihilation and reproduces the “weak cusp” found by Vasiliev for DM deep within the spike and away from its boundaries. The DM density in the cusp varies as $r^{-1/2}$ for $s$-wave annihilation, where $r$ is the distance from the central black hole, and is not a flat “plateau” profile. We then extend this model by incorporating a loss cone that accounts for the capture of DM particles by the hole. The loss cone is implemented by a boundary condition that removes capture orbits, resulting in an anisotropic distribution function. Finally, we evolve an initial spike distribution function by integrating the Boltzmann equation to show how the weak cusp grows and its density decreases with time. We treat two cases, one for $s$-wave and the other for $p$-wave DM annihilation, adopting parameters characteristic of the Milky Way nuclear core and typical WIMP models for DM. The cusp density profile for $p$-wave annihilation is weaker, varying like $\sim r^{-0.34}$, but is still not a flat plateau.

The order of the superconducting phase transition is analyzed via the functional renormalization group approach. For the first time, we derive fully analytic expressions for the $\beta$ functions of the charge and the self-coupling in the Abelian Higgs model with one complex scalar field in $d=3$ dimensions that support the existence of two charged fixed points: an infrared (IR) stable fixed point describing a second-order phase transition and a tricritical fixed point controlling the region of the parameter space that is attracted by the former one. It is found that the region separating first- and second-order transitions can be uniquely characterized by the Ginzburg-Landau parameter $\kappa$, and the system undergoes a second-order transition only if $\kappa >{\kappa }_c\approx 0.62/\sqrt{2}$.

We study the Drell-Yan process at the Large Hadron Collider in the presence of the noncommutative extension of the standard model. Using the Seiberg-Witten map, we calculate the production cross section to first order in the noncommutative parameter ${\mathrm{\Theta }}_{\mu \nu }$. Although this idea has been evolving for a long time, only a limited amount of phenomenological analysis has been completed, and this was mostly in the context of the linear collider. An outstanding feature from this nonminimal noncommutative standard model not only modifies the couplings over the SM production channel but also allows additional nonstandard vertices which can play a significant role. Hence, in the Drell-Yan process, as studied in the present analysis, one also needs to account for the gluon fusion process at the tree level. Some of the characteristic signatures, such as oscillatory azimuthal distributions, are an outcome of the momentum-dependent effective couplings. We explore the noncommutative scale ${\mathrm{\Lambda }}_{\mathrm{NC}}\ge 0.4\mathrm{TeV}$, considering different machine energy ranging from 7 to 13 TeV.

BABAR, Belle, and recently LHCb have reported an excess in the measurements of $R(D^{*})$, $R(D)$, and $\mathcal{B}r(B\to \tau {\nu }_{\tau })$ than expected from the standard model (SM), a possible signature of lepton flavor universality violating New Physics (NP). In this work we analyze the phenomenological implications for these decay modes in a flipped two-Higg-doublet model with anomalously enhanced Yukawa coupling of $H^{\pm }$ to $\tau$ lepton. When experimental and theoretical errors are added in quadrature, we conclude that this phenomenological extension of the SM can give results in agreement within $1\sigma$ deviation for the combination of $R(D^{(*)})$ and $\mathcal{B}r(B\to \tau {\nu }_{\tau })$ compared to about $4\sigma$ deviation from the SM from the latest combined (BABAR, Belle, and LHCb) experimental data for these observables.

We present precise lattice computations for the $b$-quark mass, the quark mass ratios $m_b/m_c$ and $m_b/m_s$ as well as the leptonic $B$-decay constants. We employ gauge configurations with four dynamical quark flavors, up-down, strange and charm, at three values of the lattice spacing ($a\sim 0.06–0.09\mathrm{fm}$) and for pion masses as low as 210 MeV. Interpolation in the heavy quark mass to the bottom quark point is performed using ratios of physical quantities computed at nearby quark masses exploiting the fact that these ratios are exactly known in the static quark mass limit. Our results are also extrapolated to the physical pion mass and to the continuum limit and read $m_b(\overline{\mathrm{MS}},m_b)=4.26(10)\mathrm{GeV}$, $m_b/m_c=4.42(8)$, $m_b/m_s=51.4(1.4)$, $f_{Bs}=229(5)\mathrm{MeV}$, $f_B=193(6)\mathrm{MeV}$, $f_{Bs}/f_B=1.184(25)$ and $(f_{Bs}/f_B)/(f_K/f_{\pi })=0.997(17)$.