Ghost-free theories beyond the Horndeski class exhibit a partial breaking of the Vainshtein mechanism inside nonrelativistic sources of finite extent. We exploit this breaking to identify new and novel astrophysical probes of these theories. Nonrelativistic objects feel a gravitational force that is weaker than that predicted by general relativity. The new equation of hydrostatic equilibrium is derived and solved to predict the modified behavior of stars. It is found that main-sequence stars are dimmer and cooler than their general relativity counterparts but the red giant phase is largely indistinguishable. The rotation curves and lensing potential of Milky Way–like galaxies are calculated. The circular velocities are smaller than predicted by general relativity at fixed radius and the lensing mass is smaller than the dynamical mass. We discuss potential astrophysical probes of these theories and identify strong lensing as a particularly promising candidate.

We show that the 3-3-1 model with minimal lepton content can work as a two-Higgs-triplet 3-3-1 model while leaving the other scalars as inert particles responsible for dark matter. We study two cases of dark matter, corresponding to the doublet and singlet scalar candidates, and we determine the parameter spaces in the WMAP-allowed region of relic density. Indirect and direct searches for dark matter in both cases are investigated by using micrOMEGAs.

Phenomena that involve two or more on-shell particles are particularly sensitive to the effects of finite volume and require special treatment when computed using lattice QCD. In this paper we generalize the results of Lüscher and Lellouch and Lüscher, which determine the leading-order effects of finite volume on the two-particle spectrum and two-particle decay amplitudes to determine the finite-volume effects in the second-order mixing of the $K^0$ and $\overline{K^0}$ states. We extend the methods of Kim, Sachrajda, and Sharpe to provide a direct, uniform treatment of these three, related, finite-volume corrections. In particular, the leading, finite-volume corrections to the $K_L-K_S$ mass difference $\mathrm{\Delta }{M}_K$ and the $\mathrm{CP}$-violating parameter ${\epsilon }_K$ are determined, including the potentially large effects which can arise from the near degeneracy of the kaon mass and the energy of a finite-volume, two-pion state.

We present a precise nonperturbative determination of the renormalization constants in the mass independent RI’-MOM scheme. The lattice implementation uses the Iwasaki gauge action and four degenerate dynamical twisted-mass fermions. The gauge configurations are provided by the ETM Collaboration. Renormalization constants for scalar, pseudoscalar, vector and axial operators, as well as the quark propagator renormalization, are computed at three different values of the lattice spacing, two volumes and several twisted-mass parameters. The method we developed allows for a precise cross-check of the running, thanks to the particular proper treatment of hypercubic artifacts. Results for the twist-2 operator $O_{44}$ are also presented.

We present a systematic study of the production of the heavy quarkonium, i.e., $|(c\overline{c})[n]⟩$, $|(b\overline{c})[n]⟩$ (or $|(c\overline{b})[n]⟩$), and $|(b\overline{b})[n]⟩$ quarkonium [$|(Q\overline{Q^{\prime }})[n]⟩$ quarkonium for short], through $Z^0$ boson semiexclusive decays with new parameters [1] for the heavy quarkonium under the framework of the nonrelativistic QCD, where $[n]$ stands for $n{{}^{1}S}_0$, $n{{}^{3}S}_1$, $n{{}^{1}P}_0$, $n{{}^{3}P}_J$ [$n=1,\dots ,6$; $J=(0,1,2)$]. “Improved trace technology” is adopted to derive the simplified analytic expressions at the amplitude level, which shall be useful for dealing with these decay channels. If all higher $|(Q\overline{Q^{\prime }})[n]⟩$ quarkonium states decay to the ground state $|(Q\overline{Q^{\prime }})[1{{}^{1}S}_0]⟩$ with 100% efficiency via electromagnetic or hadronic interactions, we obtain $\mathrm{\Gamma }(Z^0\to |(c\overline{c})[1{{}^{1}S}_0]⟩)=1476\mathrm{KeV}$, $\mathrm{\Gamma }(Z^0\to |(b\overline{c})[1{{}^{1}S}_0]⟩)=1485\mathrm{KeV}$, $\mathrm{\Gamma }(Z^0\to |(b\overline{b})[1{{}^{1}S}_0]⟩)=127.5\mathrm{KeV}$. At the LHC and ILC with the luminosity $\mathcal{L}\propto {10}^{34}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$, sizable heavy quarkonium events can be produced through $Z^0$ boson decays; i.e., about $5.9\times {10}^5$ $(c\overline{c})$, $6.0\times {10}^5$ $(b\overline{c})$ [or $(c\overline{b})$], $5.1\times {10}^4$ $(b\overline{b})$ events per year can be obtained.

A measurement is presented of the $t\overline{t}$ inclusive production cross section in $pp$ collisions at a center-of-mass energy of $\sqrt{s}=8\mathrm{TeV}$ using data collected by the ATLAS detector at the CERN Large Hadron Collider. The measurement was performed in the $\text{lepton}+\text{jets}$ final state using a data set corresponding to an integrated luminosity of $20.3{\mathrm{fb}}^{-1}$. The cross section was obtained using a likelihood discriminant fit and $b$-jet identification was used to improve the signal-to-background ratio. The inclusive $t\overline{t}$ production cross section was measured to be $260\pm 1{(\text{stat})}_{-23}^{+22}(\text{stat})\pm 8(\text{lumi})\pm 4(\text{beam})\mathrm{pb}$ assuming a top-quark mass of 172.5 GeV, in good agreement with the theoretical prediction of ${253}_{-15}^{+13}\mathrm{pb}$. The $t\overline{t}\to (e,\mu )+\text{jets}$ production cross section in the fiducial region determined by the detector acceptance is also reported.

The axion electromagnetic anomaly induces an oscillating electric dipole for any static magnetic dipole. Static electric dipoles do not produce oscillating magnetic moments. This is a low-energy theorem which is a consequence of the spacetime-dependent cosmic background field of the axion in the limit that it is only locally time dependent $(\overrightarrow{v}/c=0)$. The electron will acquire an oscillating electric dipole of frequency $m_a$ and strength $\sim {10}^{-32}\mathrm{e}\text{−}\mathrm{cm}$, 2 orders of magnitude above the nucleon, and within 4 orders of magnitude of the present standard model limit on a constant electron electric dipole moment. This may suggest sensitive new experimental venues for the axion dark-matter search.

We study deformations of the Klebanov-Strassler background parametrized by the size of a dim-6 VEV. In the UV, these solutions describe the usual duality cascade of Klebanov-Strassler; however, below the scale ${\rho }_{*}$ set by the dim-6 VEV they exhibit hyperscaling violation over a range of the radial coordinate. Focusing on the spectrum of scalar glueballs, we find a parametrically light state, the mass of which is suppressed by ${\rho }_{*}$, becoming massless in the limit of ${\rho }_{*}\to \infty$. Along the way, we clarify the choice of IR and UV boundary conditions for the fluctuations in the bulk, and find agreement with previous calculations for the spectrum of Klebanov-Strassler.

We model the (holographic) QCD Pomeron as a long and stretched (fixed impact parameter) transverse quantum string in flat $D_{\perp }=3$ dimensions. After discretizing the string in $N$ string bits, we analyze its length, mass and spatial distribution for large $N$ or low $x$ ($x=1/N$), and away from its Hagedorn point. The string bit distribution shows sizable asymmetries in the transverse plane that may translate to azimuthal asymmetries in primordial particle production in the Pomeron kinematics, and the flow moments in minimum bias $pp$ and $pA$ events. At moderately low $x$ and relatively small string self-interactions $g_s\approx {\alpha }_s$ (the gauge coupling), a presaturation phase is identified whereby the string transverse area undergoes a sharp transition from a large diffusive growth to a small fixed size area set by few string lengths $l_s$. For lower values of $x$ the transverse string bit density is shown to increase as $1/x$ before saturating at the Bekenstein bound of one bit per Planck area with the Planck length $l_P/l_s\approx {\alpha }_s^{2/3}$. We argue that the effects of the ${\mathrm{AdS}}_5$ curvature on the interacting string may be estimated using an effective transverse dimension between the interacting string bits. The result is a smoother transition with a transverse string bit density increasing as $1/x^{0.31}$.

We examine vacuum fluctuations in theories with modified dispersion relations which represent dimensional reduction at high energies. By changing units of energy and momentum we can obtain a description rendering the dispersion relations undeformed and transferring all the nontrivial effects to the integration measure in momentum space. Using this description we propose a general quantization procedure, which should be applicable whether or not the theory explicitly introduces a preferred frame. Based on this scheme we evaluate the power spectrum of quantum vacuum fluctuations. We find that in all theories which run to two dimensions in the ultraviolet the vacuum fluctuations, in the ultraviolet regime, are scale invariant. This is true in flat space but also for “inside the horizon” modes in an expanding universe. We spell out the conditions upon the gravity theory for this scale invariance to be preserved as the modes are frozen-in outside the horizon. We also digress on the meaning of dimensionality (in momentum and position space) and suggest that the spectral index could itself provide an operational definition of dimensionality.

In this work, we consider the Casimir effect due to massless fermionic fields in the presence of long cylinders. More precisely, we consider the interaction between a cylinder parallel to a plate, between two parallel cylinders outside each other, and between a cylinder lying parallel inside another cylinder. We derive the explicit formulas for the Casimir interaction energies and compute the leading and the next-to-leading order terms of the small separation asymptotic expansions. As expected, the leading order terms coincide with the proximity force approximations. We compare the results of the next-to-leading order terms of different quantum fields, and show that our results support the ansatz of derivative expansions.

We use effective field theory tools to study nonconservative effects in the gravitational two-body problem in general spacetime dimension. Using the classical version of the Closed Time Path formalism, we treat both the radiative gravitational field and its dynamical sources within a single action principle. New results include the radiation-reaction effective action in arbitrary dimensions to leading and $+1\mathrm{PN}$ orders, as well as the generalized quadrupole formula to order $+1\mathrm{PN}$.

We show that analog gravity systems exist for charged, planar black holes in asymptotic anti-de Sitter space. These black holes have been employed to describe, via the gauge-gravity duality, strongly coupled condensed matter systems on the boundary of anti-de Sitter (AdS) space. The analog gravity system is a different condensed matter system that, in a suitable limit, describes the same bulk physics as the theory on the AdS boundary. This combination of the gauge-gravity duality and analog gravity therefore suggests a duality between different condensed matter systems.

Antideuterons are a potential messenger for dark matter annihilation or decay in our own Galaxy, with very low backgrounds expected from astrophysical processes. The standard coalescence model of antideuteron formation, while simple to implement, is shown to be under considerable strain by recent data from the LHC. We suggest a new empirically based model, with only one free parameter, which is better able to cope with these data, and we explore the consequences of the model for dark matter searches.

We give a general method to find exact cosmological solutions for scalar-field dark energy in the presence of perfect fluids. We use the existence of invariant transformations for the Wheeler De Witt (WdW) equation. We show that the existence of a point transformation under which the WdW equation is invariant is equivalent to the existence of conservation laws for the field equations, which indicates the existence of analytical solutions. We extend previous work by providing exact solutions for the Hubble parameter and the effective dark-energy equation of state parameter for cosmologies containing a combination of perfect fluid and a scalar field whose self-interaction potential is a power of hyperbolic functions. We find solutions explicitly when the perfect fluid is radiation or cold dark matter and determine the effects of nonzero spatial curvature. Using the Planck 2015 data, we determine the evolution of the effective equation of state of the dark energy. Finally, we study the global dynamics using dimensionless variables. We find that if the current cosmological model is Liouville integrable (admits conservation laws) then there is a unique stable point which describes the de-Sitter phase of the universe.

Primordial black holes (PBHs) are theoretical black holes which can be formed during the radiation dominant era through the gravitational collapse of radiational overdensities. It has been well known that in the context of the structure formation in our Universe such collapsed objects, e.g., halos/galaxies, could be considered as bias tracers of underlying matter fluctuations and the halo/galaxy bias has been studied well. Applying such a biased tracer picture to PBHs, we investigate the large scale clustering of PBHs and obtain an almost mass-independent constraint to the scenario that the dark matter (DM) consists of PBHs. We focus on the case where the statistics of the primordial curvature perturbations is almost Gaussian, but with small local-type non-Gaussianity. If PBHs account for the DM abundance, such a large scale clustering of PBHs behaves as nothing but the matter isocurvature perturbation which is strictly constrained by the observations of cosmic microwave backgrounds (CMBs). From this constraint, we show that, in the case where a certain single field causes both CMB temperature perturbations and PBH formation, the PBH-DM scenario is excluded even with quite small local-type non-Gaussianity, $|f_{\mathrm{NL}}|\sim \mathcal{O}(0.01)$.

Lepton flavor violating Higgs decays can arise in flavor symmetry models where the Higgs sector is responsible for both the electroweak and the flavor symmetry breaking. Here we advocate an $S_4$ three-Higgs-doublet model where tightly constrained flavor changing neutral currents are suppressed by a remnant $Z_3$ symmetry. A small breaking of this $Z_3$ symmetry can explain the $2.4\sigma$ excess of Higgs decay final states with a $\mu \tau$ topology reported recently by CMS if the new neutral scalars are light. The model also predicts sizable rates for lepton flavor violating Higgs decays in the $e\tau$ and $e\mu$ channels because of the unifying $S_4$ flavor symmetry.

We present our analysis of the decay constants of the beauty vector mesons $B^{*}$ and $B_s^{*}$ within the framework of dispersive sum rules for the two-point correlator of vector currents in QCD. While the decay constants of the vector mesons $f_{B^{*}}$ and $f_{B_s^{*}}$—similar to the decay constants of the pseudoscalar mesons $f_B$ and $f_{B_s}$—individually have large uncertainties induced by theory parameters not known with a satisfactory precision, these uncertainties almost entirely cancel out in the ratios of vector over pseudoscalar decay constants. These ratios, thus, may be predicted with very high accuracy due to the good control over the systematic uncertainties of the decay constants gained upon application of our hadron-parameter extraction algorithm. Our final results read $f_{B^{*}}/f_B=0.944\pm 0.011_{\mathrm{OPE}}\pm 0.018_{\text{syst}}$ and $f_{B_s^{*}}/f_{B_s}=0.947\pm 0.023_{\mathrm{OPE}}\pm 0.020_{\text{syst}}$. Thus, both $f_{B^{*}}/f_B$ and $f_{B_s^{*}}/f_{B_s}$ are less than unity at $2.5\sigma$ and $2\sigma$ level, respectively.

Higgs signatures from the cascade decays of light top squarks are an interesting possibility in the next-to-minimal supersymmetric standard model (NMSSM). We investigate the potential reach of the light top-squark mass at the 13 TeV run of the LHC by means of five NMSSM benchmark points where this signature is dominant. These benchmark points are compatible with current Higgs coupling measurements, LHC constraints, dark matter relic density and direct-detection constraints. We consider single and dilepton search strategies, as well as the jet-substructure technique to reconstruct the Higgs bosons. We find that one can probe top-squark masses up to 1.2 TeV with $300{\mathrm{fb}}^{-1}$ luminosity via the dilepton channel, while with the jet-substructure method, top-squark masses up to 1 TeV can be probed with $300{\mathrm{fb}}^{-1}$ luminosity. We also investigate the possibility of the appearance of multiple Higgs peaks over the background in the fat-jet mass distribution, and conclude that such a possibility is viable only at the high-luminosity run of the 13 TeV LHC.