We study the effects of lepton flavor violation (LFV) in the scalar lepton sector of the MSSM on precision observables such as the $W$-boson mass and the effective weak leptonic mixing angle, and on the Higgs-boson mass predictions. The slepton mass matrices are parametrized in a model-independent way by a complete set of dimensionless parameters which we constrain through LFV decay processes and the precision observables. We find regions where both conditions are similarly constraining. The necessary prerequisites for the calculation have been added to FeynArts and FormCalc and are thus publicly available for further studies. The obtained results are available in FeynHiggs.

The recent measurement of the Lamb shift in muonic hydrogen allows for the most precise extraction of the charge radius of the proton which is currently in conflict with other determinations based on $e-p$ scattering and hydrogen spectroscopy. This discrepancy could be the result of some new muon-specific force with O(1–100) MeV force carrier—in this paper we concentrate on vector mediators. Such an explanation faces challenges from the constraints imposed by the $g-2$ of the muon and electron as well as precision spectroscopy of muonic atoms. In this work we complement the family of constraints by calculating the contribution of hypothetical forces to the muonium hyperfine structure. We also compute the two-loop contribution to the electron parity-violating amplitude due to a muon loop, which is sensitive to the muon axial-vector coupling. Overall, we find that the combination of low-energy constraints favors the mass of the mediator to be below 10 MeV and that a certain degree of tuning is required between vector and axial-vector couplings of new vector particles to muons in order to satisfy constraints from muon $g-2$. However, we also observe that in the absence of a consistent standard model embedding high-energy weak-charged processes accompanied by the emission of new vector particles are strongly enhanced by $(E/m_V{)}^2$, with $E$ a characteristic energy scale and $m_V$ the mass of the mediator. In particular, leptonic $W$ decays impose the strongest constraints on such models completely disfavoring the remainder of the parameter space.

Measurements of normalized differential cross sections for top-quark pair production are presented as a function of the top-quark transverse momentum, and of the mass, transverse momentum, and rapidity of the $t\overline{t}$ system, in proton–proton collisions at a center-of-mass energy of $\sqrt{s}=7\mathrm{TeV}$. The data set corresponds to an integrated luminosity of $4.6{\mathrm{fb}}^{-1}$, recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. Events are selected in the $\mathrm{lepton}+\text{jets}$ channel, requiring exactly one lepton and at least four jets with at least one of the jets tagged as originating from a $b$-quark. The measured spectra are corrected for detector efficiency and resolution effects and are compared to several Monte Carlo simulations and theory calculations. The results are in fair agreement with the predictions in a wide kinematic range. Nevertheless, data distributions are softer than predicted for higher values of the mass of the $t\overline{t}$ system and of the top-quark transverse momentum. The measurements can also discriminate among different sets of parton distribution functions.

We reconsider the generalized flare-out conditions in static wormhole throats given by Hochberg and Visser. We show that, due to the presence of matter sources on the throat, these conditions are not applicable to the thin-shell wormholes.

The interaction induced chiral asymmetry is calculated in cold QED plasma beyond the weak-field approximation. By making use of the recently developed Landau-level representation for the fermion self-energy, the chiral shift and the parity-even chiral chemical potential function are obtained with the help of numerical methods. The results are used to quantify the chiral asymmetry of the Fermi surface in dense QED matter. Because of the weakness of the QED interactions, the value of the asymmetry appears to be rather small even in the strongest magnetic fields and at the highest stellar densities. However, the analogous asymmetry can be substantial in the case of dense quark matter.

In light of the development of the Gribov issue for pure Euclidean gauge theories and of the recent lattice measurement of soft breaking of the BRST invariance in Yang-Mills theories in the Landau gauge, we consider nonperturbative features in the gauge-interacting matter sector and their relation with general properties of the Faddeev-Popov operator. A signature for BRST breaking in the matter sector is proposed and a local and renormalizable framework is constructed, accommodating this signature and predicting nonperturbative matter propagators that are consistent with available lattice data for adjoint scalars and quarks.

Compact binaries that emit gravitational waves in the sensitivity band of ground-based detectors can have non-negligible eccentricities just prior to merger, depending on the formation scenario. We develop a purely analytic, frequency-domain model for gravitational waves emitted by compact binaries on orbits with small eccentricity, which reduces to the quasicircular post-Newtonian approximant TaylorF2 at zero eccentricity and to the postcircular approximation of Yunes et al. [Phys. Rev. D 80, 084001 (2009)] at small eccentricity. Our model uses a spectral approximation to the (post-Newtonian) Kepler problem to model the orbital phase as a function of frequency, accounting for eccentricity effects up to $\mathcal{O}(e^8)$ at each post-Newtonian order. Our approach accurately reproduces an alternative time-domain eccentric waveform model for $e\in [0,0.4]$ and binaries with total mass $\lesssim 12M_{\odot }$. As an application, we evaluate the signal amplitude that eccentric binaries produce in different networks of existing and forthcoming gravitational waves detectors. Assuming a population of eccentric systems containing black holes and neutron stars that is uniformly distributed in comoving volume, we estimate that second-generation detectors like Advanced LIGO could detect approximately 0.1–10 events per year out to redshift $z\sim 0.2$, while an array of Einstein Telescope detectors could detect hundreds of events per year to redshift $z\sim 2.3$.

We analyze the relationship between entanglement (or geometric) entropy with statistical mechanical entropy of horizon degrees of freedom when described in the framework of isolated horizons in loop quantum gravity. We show that, once the relevant degrees of freedom are identified, the two notions coincide. The key ingredient linking the two notions is the structure of quantum geometry at Planck scale implied by loop quantum gravity, where correlations between the inside and outside of the black hole are mediated by eigenstates of the horizon area operator.

The nonlinear behavior of higher dimensional black hole spacetimes is of interest in several contexts, ranging from an understanding of cosmic censorship to black hole production in high-energy collisions. However, nonlinear numerical evolutions of higher dimensional black hole spacetimes are tremendously complex, involving different diagnostic tools and “dimensional reduction methods.” In this work we compare two different successful codes to evolve Einstein’s equations in higher dimensions, and show that the results of such different procedures agree to numerical precision, when applied to the collision from rest of two equal-mass black holes. We calculate the total radiated energy to be $E_{\text{rad}}/M=(9.0\pm 0.5)\times 10^{-4}$ in five dimensions and $E_{\text{rad}}/M=(8.1\pm 0.4)\times 10^{-4}$ in six dimensions.

This paper considers the nature of apparent horizons for astrophysical black holes situated in a realistic cosmological context. Using semitetrad covariant methods we study the local evolution of the boundaries of the trapped region in the spacetime. For a collapsing massive star immersed in a cosmology with cosmic background radiation (CBR), we show that the initial two-dimensional marginally trapped surface bifurcates into inner and outer horizons. The inner horizon is timelike while the continuous CBR influx into the black hole makes the outer horizon spacelike. We discuss the possible consequences of these features for Hawking radiation in realistic astrophysical contexts.

In the light of new observational results, we discuss the status of the exponential potentials driving inflation. We depart from the minimal scenario and study an inflaton kinetically coupled to the Einstein tensor. We find that in this case, the exponential potentials are well compatible with observations. Their predictions coincide with those of the chaotic-type quadratic potential for an inflaton minimally coupled to gravity. We show that there exists a simple mapping between the two models. Moreover, a novel aspect of our model is that it features a natural exit from the inflationary phase even in the absence of a minimum. We also turn to supergravity and motivate this sort of potential and the nonminimal kinetic coupling as possible effective dilaton theories.

We propose a cosmological model that describes isotropic expansion of an inhomogeneous universe. The energy-momentum tensor that creates the spatial inhomogeneity may not affect the uniform expansion scaling factor $a(t)$ in the Friedmann-Lemaître-Robertson-Walker-like metrics. Such an energy-momentum tensor may not be exotic; in fact any linear or nonlinear $\sigma$ model has this feature. We show that the classical spatial inhomogeneity can be embedded in both inflation models and the traditional cosmological expansion by perfect fluid. The spatial inhomogeneity resembles the primordial quantum perturbation that was frozen in the comoving frame. We obtain some exact inhomogeneous solutions with spherical or axial symmetries. We also show that some of our cosmological models can be viewed as the dynamical black hole formation.

The LHC phenomenology of a low-scale gauged flavor symmetry model with inverted hierarchy is studied, through introduction of a simplified model of broken flavor symmetry. A new scalar (a flavon) and a new neutral top-philic massive gauge boson emerge with mass in the TeV range, along with a new heavy fermion associated with the standard model top quark. After checking constraints from electroweak precision observables, we investigate the influence of the model on Higgs boson physics, notably on its production cross section and decay branching fractions. Limits on the flavon $\phi$ from heavy Higgs boson searches at the LHC at 7 and 8 TeV are presented. The branching fractions of the flavon are computed as a function of the flavon mass and the Higgs-flavon mixing angle. We also explore possible discovery of the flavon at 14 TeV, particularly via the $\phi \to Z^0{Z}^0$ decay channel in the $2\ell 2{\ell }^{\prime }$ final state, and through standard model Higgs boson pair production $\phi \to hh$ in the $b\overline{b}\gamma \gamma$ final state. We conclude that the flavon mass range up to 500 GeV could be probed down to quite small values of the Higgs-flavon mixing angle with $100{\mathrm{fb}}^{-1}$ of integrated luminosity at 14 TeV.

Motivated by the new observed scalar boson of 126 GeV at ATLAS and CMS, various phenomena in the two-Higgs-doublet model are investigated broadly in the literature. For considering the model that possesses a solution to the massive neutrinos, we study the simplest extension of conventional type-II seesaw model to two Higgs doublets. We find that the new interactions in the scalar potential cause the sizable mixture of charged Higgses in a triplet and doublets. As a result, we have a completely different decay pattern for doubly charged Higgs (${\delta }^{\pm \pm }$); even the vacuum expectation value of a Higgs triplet is at GeV level, which is limited by the precision measurement for the $\rho$ parameter. For illustrating the new characters of the model, we study the influence of new interactions on the new open channels ${\delta }^{++}\to (H_1^{+}{W}^{{+}^{(*)}},H_1^{+}{H}_1^{+})$ with $H_1^{+}$ being the lightest charged Higgs. Additionally, due to the new mixing effect, the triplet charged Higgs could couple to quarks in the model; therefore, the search for ${\delta }^{++}$ via ${\delta }^{++}\to tb{W}^{+}\to b\overline{b}{W}^{+}{W}^{+}$ by mediated $H_1^{+}$ becomes significant.

The spectrum of the SU(2) flavor baryons is studied in the frame of a relativistic chiral quark potential model based on the one-pion and one-gluon exchange mechanisms. It is argued that the $N^{*}$ and ${\mathrm{\Delta }}^{*}$ resonances strongly coupled to the $\pi N$ channel are identified with the orbital configurations $(1S_{1/2}{)}^2(nlj)$ with a single valence quark in the excited state ($nlj$). With the obtained selection rules based on the “chiral constraint,” we show that it is possible to construct a schematic periodic table of baryon resonances, consistent with the experimental data and yielding no “missing resonances.” A new original method for the treatment of the center of mass problem is suggested which is based on the separation of the three-quark Dirac Hamiltonian into the parts, corresponding to the Jacobi coordinates. The numerical estimations for the energy positions of the nucleon and delta baryons (up to and including F-wave $N^{*}$ and ${\mathrm{\Delta }}^{*}$ resonances), obtained within the field-theoretical framework by using time ordered perturbation theory, yield an overall good description of the experimental data at the level of the relativized constituent quark model of S. Capstick and W. Roberts without any fitting parameters. The only free parameter of the linear confinement potential was fitted previously by Th. Gutsche to reproduce the axial charge of the nucleon. The ground state $\mathrm{\Delta }(1232)$ is well reproduced. However, nucleon ground state and most of the radially excited baryon resonances (including Roper) are overestimated. On the contrary, the first band of the orbitally excited baryon resonances with a negative parity are underestimated. At the same time, the second band of the orbitally excited ${\mathrm{\Delta }}^{*}$ states with the negative parity are mostly overestimated, while the $N^{*}$ states are close to the experimental boxes. The theoretical estimations of the energy levels for the positive parity baryon resonances with $\mathrm{J}=5/2$, $7/2$ are close to the experimental data. At higher energies, where the experimental data are poor, we can extend our model schematically and predict an existence of seven $N^{*}$ and four ${\mathrm{\Delta }}^{*}$ new states with larger spin values.

The top quark with its large Yukawa coupling is crucially important to explore TeV scale physics. Therefore, the study of the Higgs-top sector is highly motivated to look for any deviations from the standard model predictions. The most general lowest-order Lagrangian for the Higgs-top Yukawa coupling has scalar ($\kappa$) and pseudoscalar ($\tilde{\kappa }$) components. Currently, these couplings are constrained indirectly using the present experimental limits on the Higgs-$\gamma$-$\gamma$ and Higgs-gluon-gluon couplings. Furthermore, stronger bounds on $\kappa$ and $\tilde{\kappa }$ are obtained using the limits on the electric dipole moments (EDM). In this paper, we propose an asymmetrylike observable $O_{\varphi }$ in $t\overline{t}H$ production at the LHC to probe the Higgs-top coupling and to distinguish between the scalar and pseudoscalar components. We also show that the presence of the pseudoscalar component in the Higgs-top Yukawa coupling leads to a sizeable value for the top quark EDM. It is shown that a limit of $10^{-19}e\mathrm{.}\mathrm{cm}$, which is achievable by the future $e^{-}{e}^{+}$ collider, allows us to exclude a significant region in the $(\kappa ,\tilde{\kappa })$ plane.