We study models of gauge-mediated supersymmetry breaking with messengers that do not belong to complete representations of grand-unified gauge groups. We show that certain setups characterized by a heavy Wino can greatly improve the fine-tuning with respect to models with unified messengers, such as minimal gauge mediation. The typical models with low-tuning feature multi-TeV superparticles, with the exception of the Higgsinos and possibly Bino and right-handed sleptons. As a consequence, the absence of signals for supersymmetry at the LHC is trivially accommodated in our framework. On the other hand, testing these models will be challenging at the LHC. We finally show that the gravitino can be a consistent candidate for cold dark matter, provided a rather low reheating temperature, if a standard thermal history of the Universe is assumed.

We present a comprehensive comparison of the available experimental data for the Drell-Yan lepton angular coefficients $\lambda$ and $\nu$ to calculations at leading and next-to-leading order of perturbative QCD. To obtain the next-to-leading order corrections, we make use of publicly available numerical codes that allow us to compute the Drell-Yan cross section at second order in perturbation theory and from which the contributions we need can be extracted. Our comparisons reveal that perturbative QCD is able to describe the experimental data overall rather well, especially at colliders, but also in the fixed-target regime. On the basis of the angular coefficients alone, there appears to be little (if any) convincing evidence for effects that go beyond fixed-order collinear factorized perturbation theory, although the presence of such effects is not ruled out.

Unitarity is a fundamental property of any theory required to ensure we work in a theoretically consistent framework. In comparison with the quark sector, experimental tests of unitarity for the $3\times 3$ neutrino mixing matrix are considerably weaker. We perform a reanalysis to see how global knowledge is altered when one refits oscillation results without assuming unitarity, and present $3\sigma$ ranges for allowed $U_{\mathrm{PMNS}}$ elements consistent with all observed phenomena. We calculate, for the first time, bounds on the closure of the six neutrino unitarity triangles, with the closure of the ${\nu }_e{\nu }_{\mu }$ triangle being constrained to be $\le 0.03$, while the remaining triangles are significantly less constrained to be $\le 0.1–0.2$. Similarly for the row and column normalization, we find their deviation from unity is constrained to be $\le 0.2–0.4$, for four out of six such normalizations, while for the ${\nu }_{\mu }$ and ${\nu }_e$ row normalization the deviations are constrained to be $\le 0.07$, all at the $3\sigma$ CL. We emphasize that there is significant room for new low energy physics, especially in the ${\nu }_{\tau }$ sector which very few current experiments constrain directly.

The NEMO-3 experiment at the Modane Underground Laboratory investigates the double-beta decay of ${}^{48}\mathrm{Ca}$. Using 5.25 yr of data recorded with a 6.99 g sample of ${}^{48}\mathrm{Ca}$, approximately 150 double-beta decay candidate events are selected with a signal-to-background ratio greater than 3. The half-life for the two-neutrino double-beta decay of ${}^{48}\mathrm{Ca}$ is measured to be $T_{1/2}^{2\nu }=[6.4_{-0.6}^{+0.7}{(\mathrm{stat})}_{-0.9}^{+1.2}(\mathrm{syst})]\times 10^{19}\mathrm{yr}$. A search for neutrinoless double-beta decay of ${}^{48}\mathrm{Ca}$ yields a null result, and a corresponding lower limit on the half-life is found to be $T_{1/2}^{0\nu }>2.0\times 10^{22}\mathrm{yr}$ at 90% confidence level, translating into an upper limit on the effective Majorana neutrino mass of $⟨m_{\beta \beta }⟩<6.0–26\mathrm{eV}$, with the range reflecting different nuclear matrix element calculations. Limits are also set on models involving Majoron emission and right-handed currents.

We study matter-coupled $N=3$ gauged supergravity in four dimensions with various semisimple gauge groups. When coupled to $n$ vector multiplets, the gauged supergravity contains $3+n$ vector fields and $3n$ complex scalars parametrized by $SU(3,n)/SU(3)\times SU(n)\times U(1)$ coset manifold. Semisimple gauge groups take the form of $G_0\times H\subset SO(3,n)\subset SU(3,n)$ with $H$ being a compact subgroup of $SO(n+3-\dim (G_0))$. The $G_0$ groups considered in this paper are of the form $SO(3)$, $SO(3,1)$, $SO(2,2)$, $SL(3,\mathbb{R})$ and $SO(2,1)\times SO(2,2)$. We find that $SO(3)\times SO(3)$, $SO(3,1)$ and $SL(3,\mathbb{R})$ gauge groups admit a maximally supersymmetric ${\mathrm{AdS}}_4$ critical point. The $SO(2,1)\times SO(2,2)$ gauge group admits a supersymmetric Minkowski vacuum while the remaining gauge groups admit both half-supersymmetric domain wall vacua and ${\mathrm{AdS}}_4$ vacua with completely broken supersymmetry. For the $SO(3)\times SO(3)$ gauge group, there exists another supersymmetric $N=3$ ${\mathrm{AdS}}_4$ critical point with $SO(3{)}_{\mathrm{diag}}$ symmetry. We explicitly give a detailed study of various holographic RG flows between ${\mathrm{AdS}}_4$ critical points, flows to nonconformal theories, and supersymmetric domain walls in each gauge group. The results provide gravity duals of $N=3$ Chern-Simons-matter theories in three dimensions.

We study the turbulent regime of chiral (magneto)hydrodynamics for charged and neutral matter with chirality imbalance. We find that the chiral magnetohydrodynamics for charged plasmas possesses a unique scaling symmetry, only without fluid helicity under the local charge neutrality. We also find a different type of unique scaling symmetry in the chiral hydrodynamics for neutral matter with fluid helicity in the inertial range. We show that these symmetries dictate the self-similar inverse cascade of the magnetic and kinetic energies. Our results imply the possible inverse energy cascade in core-collapse supernovae due to the chiral transport of neutrinos.

We evaluate the difference between the Casimir free energies corresponding to either grounded or isolated perfect conductors, at high temperatures. We show that a general and simple expression for that difference can be given, in terms of the electrostatic capacitance matrix for the system of conductors. For the case of close conductors, we provide approximate expressions for that difference, by evaluating the capacitance matrix using the proximity force approximation. Since the high-temperature limit for the Casimir free energy for a medium described by a frequency-dependent conductivity diverging at zero frequency coincides with that of an isolated conductor, our results may shed light on the corrections to the Casimir force in the presence of real materials.

The equivalence between theories depending on the derivatives of $R$, i.e. $f(R,\nabla R,\dots ,{\nabla }^{n}R)$, and scalar-multi-tensorial theories is verified. The analysis is done in both metric and Palatini formalisms. It is shown that $f(R,\nabla R,\dots ,{\nabla }^{n}R)$ theories are equivalent to scalar-multi-tensorial ones resembling Brans-Dicke theories with kinetic terms ${\omega }_0=0$ and ${\omega }_0=-\frac{3}{2}$ for metric and Palatini formalisms respectively. This result is analogous to what happens for $f(R)$ theories. It is worth emphasizing that the scalar-multi-tensorial theories obtained here differ from Brans-Dicke ones due to the presence of multiple tensorial fields absent in the last. Furthermore, sufficient conditions are established for $f(R,\nabla R,\dots ,{\nabla }^{n}R)$ theories to be written as scalar-multi-tensorial theories. Finally, some examples are studied and the comparison of $f(R,\nabla R,\dots ,{\nabla }^{n}R)$ theories to $f(R,\square R,\dots ,{\square }^{n}R)$ theories is performed.

A frequentist asymptotic expansion method for error estimation is employed for a network of gravitational wave detectors to assess the amount of information that can be extracted from gravitational wave observations. Mathematically we derive lower bounds in the errors that any parameter estimator will have in the absence of prior knowledge to distinguish between the post-Einsteinian (ppE) description of coalescing binary systems and that of general relativity. When such errors are smaller than the parameter value, there is a possibility to detect these violations from general relativity (GR). A parameter space with inclusion of dominant dephasing ppE parameters $(\beta ,b)$ is used for a study of first- and second-order (co)variance expansions, focusing on the inspiral stage of a nonspinning binary system of zero eccentricity detectible through Advanced LIGO and Advanced Virgo. Our procedure is an improvement of the Cramér-Rao lower bound. When Bayesian errors are lower than our bound it means that they depend critically on the priors. The analysis indicates the possibility of constraining deviations from GR in inspiral signal-to-noise ratio (SNR) ($\rho \sim 15–17$) regimes that are achievable in upcoming scientific runs (GW150914 had an inspiral $\mathrm{SNR}\sim 12$). The errors on $\beta$ also increase errors of other parameters such as the chirp mass $\mathcal{M}$ and symmetric mass ratio $\eta$. Application is done to existing alternative theories of gravity, which include modified dispersion relation of the waveform; nonspinning models of quadratic modified gravity; and dipole gravitational radiation (i.e., Brans-Dicke-type) modifications.

We investigate the cosmological applications of new gravitational scalar-tensor theories, which are novel modifications of gravity possessing $2+2$ propagating degrees of freedom, arising from a Lagrangian that includes the Ricci scalar and its first and second derivatives. Extracting the field equations we obtain an effective dark energy sector that consists of both extra scalar degrees of freedom, and we determine various observables. We analyze two specific models and we obtain a cosmological behavior in agreement with observations, i.e. transition from matter to dark energy era, with the onset of cosmic acceleration. Additionally, for a particular range of the model parameters, the equation-of-state parameter of the effective dark energy sector can exhibit the phantom-divide crossing. These features reveal the capabilities of these theories, since they arise solely from the novel, higher-derivative terms.

We study how an arbitrary Gaussian state of two localized wave packets, prepared in an inertial frame of reference, is described by a pair of uniformly accelerated observers. We explicitly compute the resulting state for arbitrarily chosen proper accelerations of the observers and independently tuned distance between them. To do so, we introduce a generalized Rindler frame of reference and analytically derive the corresponding state transformation as a Gaussian channel. Our approach provides several new insights into the phenomenon of vacuum entanglement such as the highly nontrivial effect of spatial separation between the observers including sudden death of entanglement. We also calculate the fidelity of the two-mode channel for nonvacuum Gaussian states and obtain bounds on classical and quantum capacities of a single-mode channel. Our framework can be directly applied to any continuous variable quantum information protocol in which the effects of acceleration or gravity cannot be neglected.

Quadratic gravity presents us with a renormalizable, asymptotically free theory of quantum gravity. When its couplings grow strong at some scale, as in QCD, then this strong scale sets the Planck mass. QCD has a gluon that does not appear in the physical spectrum. Quadratic gravity has a spin-2 ghost that we conjecture does not appear in the physical spectrum. We discuss how the QCD analogy leads to this conjecture and to the possible emergence of general relativity. Certain aspects of the QCD path integral and its measure are also similar for quadratic gravity. With the addition of the Einstein-Hilbert term, quadratic gravity has a dimensionful parameter that seems to control a quantum phase transition and the size of a mass gap in the strong phase.

When an electrically charged black hole is perturbed, its inner horizon becomes a singularity, often referred to as the Poisson-Israel mass inflation singularity. Ori constructed a model of this phenomenon for asymptotically flat black holes, in which the metric can be determined explicitly in the mass inflation region. In this paper we implement the Ori model for charged AdS black holes. We find that the mass function inflates faster than the flat space case as the inner horizon is approached. Nevertheless, the mass inflation singularity is still a weak singularity: Although spacetime curvature becomes infinite, tidal distortions remain finite on physical objects attempting to cross it.

We present a new class of four-dimensional AdS black holes with noncompact event horizons of finite area. The event horizons are topologically spheres with one puncture, with the puncture pushed to infinity in the form of a cusp. Because of the shape of their event horizons, we call such black holes “black bottles.” The solution was obtained as a special case of the Plebański-Demiański solution, and may describe either static or rotating black bottles. For certain ranges of parameters, an acceleration horizon may also appear in the space-time. We study the full parameter space of the solution, and the various limiting cases that arise. In particular, we show how the rotating black hole recently discovered by Klemm arises as a special limit.

A distorted black hole radiates gravitational waves in order to settle down in a smoother geometry. During that relaxation phase, a characteristic damped ringing is generated. It can be theoretically constructed from both the black hole quasinormal frequencies (which govern its oscillating behavior and its decay) and the associated excitation factors (which determine intrinsically its amplitude) by carefully taking into account the source of the distortion. In the framework of massive gravity, the excitation factors of the Schwarzschild black hole have an unexpected strong resonant behavior which, theoretically, could lead to giant and slowly decaying ringings. If massive gravity is relevant to physics, one can hope to observe these extraordinary ringings by using the next generations of gravitational wave detectors. Indeed, they could be generated by supermassive black holes if the graviton mass is not too small. In fact, by focusing on the odd-parity $\ell =1$ mode of the Fierz-Pauli field, we shall show here that such ringings are neutralized in waveforms due to (i) the excitation of the quasibound states of the black hole and (ii) the evanescent nature of the particular partial modes which could excite the concerned quasinormal modes. Despite this, with observational consequences in mind, it is interesting to note that the waveform amplitude is nevertheless rather pronounced and slowly decaying (this effect is now due to the long-lived quasibound states). It is worth noting also that, for very low values of the graviton mass (corresponding to the weak instability regime for the black hole), the waveform is now very clean and dominated by an ordinary ringing which could be used as a signature of massive gravity.

It is commonly assumed that if the optical metric of a dielectric medium is identical to the metric of a vacuum space-time then light propagation through the dielectric mimics light propagation in the vacuum. However, just as the curved surface of the Earth cannot be mapped into a flat plane without distortion of some surface features, so too is it impossible to project the behavior of light from the vacuum into a dielectric analog residing in Minkowski space-time without introducing distortions. We study the covariance properties of dielectric analog space-times and the kinematics of a congruence of light in the analog, and show how certain features can be faithfully emulated in the analog depending on the choice of projection, but that not all features can be simultaneously emulated without distortion. These findings indicate conceptual weaknesses in the idea of using analog space-times as a basis for transformation optics, and we show that a certain formulation of transformation optics closely related to analog space-times resolves these issues.

After Planck 2013, a broad class of inflationary models called $\alpha$-attractors was developed which has universal observational predictions. For small values of the parameter $\alpha$, the models have good consistency with the recent cosmic microwave background data. In this work, we first calculate analytically (and verify numerically) the predictions of these models for spectral index, $n_{\mathrm{s}}$, and tensor-to-scalar ratio, $r$, and then, using BICEP2/Keck 2015 and Planck 2015 data, we impose constraints on $\alpha$-attractors. Then, we study the reheating for $\alpha$-attractors. The reheating temperature, $T_{\mathrm{re}}$, and the number of e-folds during reheating, $N_{\mathrm{re}}$, are calculated as functions of $n_{\mathrm{s}}$. Using these results, we determine the range of the free parameters of two classes of $\alpha$-attractors which satisfy the constraints of recent cosmic microwave background data.

With the Fermi-LAT data, quite a few research groups have reported a spatially extended GeV $\gamma$-ray excess surrounding the Galactic center (GC). The physical origin of such a GeV excess is still unclear, and one interesting possibility is the inverse Compton scattering of the electrons and positrons from annihilation of self-interacting dark matter (SIDM) particles with the interstellar optical photons. In this work, we calculate the morphology of such a $\gamma$-ray emission. For the annihilation channel of $\overline{\chi }\chi \to \varphi \varphi \to e^{+}{e}^{-}{e}^{+}{e}^{-}$, the inverse Compton scattering (ICS) dominates over the bremsstrahlung on producing the GeV $\gamma$-ray emission. For the SIDM particles with a rest mass $m_{\chi }\sim$ tens GeV that may be favored by the modeling of the Galactic GeV excess, the ICS radiation at GeV energies concentrates along the Galactic plane. The degrees of asymmetry high up to $\ge 0.3$ are found in some regions of interest, which in turn proposes a plausible test on the SIDM interpretation of the GeV excess.

In this paper, we study a new class of inflation models which generalize the Dirac-Born-Infeld (DBI) action with the addition of a nonminimal kinetic coupling (NKC) term. We dub this model as the new DBI inflation model. The NKC term does not bring a new dynamical degree of freedom, so the equations of motion remain of second order. However, with such coupling, the action is no longer linear with respect to the Einstein curvature term ($R$ or $G^{\mu \nu }$), which leads to a correction term of $k^4$ in the perturbations. The new DBI inflation model can be viewed as a theory beyond Horndeski. Without violating approximate scale invariance, such correction may lead to new effects on the inflationary spectra that can be tested by future observations.