Compact binary coalescences are a promising source of gravitational waves for second-generation interferometric gravitational-wave detectors such as advanced LIGO and advanced Virgo. While most binaries are expected to possess circular orbits, some may be eccentric, for example, if they are formed through dynamical capture. Eccentric orbits can create difficulty for matched filtering searches due to the challenges of creating effective template banks to detect these signals. In previous work, we showed how seedless clustering can be used to detect low-mass ($M_{\text{total}}\le 10M_{\odot }$) compact binary coalescences for both spinning and eccentric systems, assuming a circular post-Newtonian expansion. Here, we describe a parametrization that is designed to maximize sensitivity to low-eccentricity ($0\le \epsilon \le 0.6$) systems, derived from the analytic equations. We show that this parametrization provides a robust and computationally efficient method for detecting eccentric low-mass compact binaries. Based on these results, we conclude that advanced detectors will have a chance of detecting eccentric binaries if optimistic models prove true. However, a null observation is unlikely to firmly rule out models of eccentric binary populations.

We study the stability constraints on the parameter space of a triplet extension of the Minimal Supersymmetric Standard Model (MSSM). Existence of unbounded-from-below directions in the potential can spoil successful electroweak (EW) symmetry breaking by making the corresponding minimum unstable, and hence the model should be free from those directions. Avoiding those directions restricts the parameter space of the model. We derive four stability constraints, of which only three are independent from each other. After scanning the parameter space of the model for phenomenologically viable data points, we impose the stability constraints and find that only about a quarter of the data points features a stable EW minimum. At those data points featuring stability, $\mu$ and the up Higgs soft mass turn out to be smaller than about a TeV in absolute value, which makes the mass of the lightest chargino and neutralino smaller than about 700 GeV. Two relevant phenomenological consequences of lifting the unbounded-from-below directions are that the lightest Higgs boson decay rate to diphoton predicted by the triplet extension of MSSM generally features larger deviations from MSSM, and fine-tuning is actually higher than what each of the two would be without imposing stability constraints.

We show that superstring-inspired $E_6$ models can explain both the recently detected excess $eejj$ and $e{\cancel{p}}_{T}jj$ signals at CMS and also allow for leptogenesis. Working in an $R$-parity conserving, low-energy supersymmetric effective model, we show that the excess CMS events can be produced via the decay of exotic sleptons in Alternative Left-Right Symmetric Model of $E_6$, which can also accommodate leptogenesis at a high scale. On the other hand, either the $eejj$ excess or the $e{\cancel{p}}_{T}jj$ excess can be produced via the decays of right-handed gauge bosons, but some of these scenarios may not accommodate letptogenesis as there will be strong $B-L$ violation at low energy, which, along with the anomalous fast electroweak $B+L$ violation, will wash out all baryon asymmetry. Baryogenesis below the electroweak scale may then need to be implemented in these models.

Searches for heavy neutrinos often rely on the possibility that the heavy neutrinos will decay to detectable particles. Interpreting the results of such searches requires a particular model for the heavy-neutrino decay. We present a method for placing limits on the probability that a tau can couple to a heavy neutrino, $|U_{\tau 4}{|}^2$, using only the kinematics of semileptonic tau decays, instead of a specific model. Our study suggests that $B$ factories with large data sets, such a Belle and BABAR, may be able to place stringent limits on $|U_{\tau 4}{|}^2$ as low as $\mathcal{O}({10}^{-7}-{10}^{-3})$ when $100\mathrm{MeV}\lesssim m_4\lesssim 1.2\mathrm{GeV}$, utilizing minimal assumptions regarding the decay modes of heavy neutrinos.

New neutrino degrees of freedom allow for more sources of charge parity- ($CP$) invariance violation (CPV). We explore the requirements for accessing $CP$-odd mixing parameters in the so-called $3+1$ scenario, where one assumes the existence of one extra, mostly sterile neutrino degree of freedom, heavier than the other three mass eigenstates. As a first step, we concentrate on the ${\nu }_e\to {\nu }_{\mu }$ appearance channel in a hypothetical, upgraded version of the $\nu \mathrm{STORM}$ proposal. We establish that the optimal baseline for CPV studies depends strongly on the value of $\mathrm{\Delta }{m}_{14}^2$—the new mass-squared difference—and that the ability to observe CPV depends significantly on whether the experiment is performed at the optimal baseline. Even at the optimal baseline, it is very challenging to see CPV in $3+1$ scenarios if one considers only one appearance channel. Full exploration of CPV in short-baseline experiments will require precision measurements of tau appearance, a challenge significantly beyond what is currently being explored by the experimental neutrino community.

A search for resonances and quantum black holes is performed using the dijet mass spectra measured in proton-proton collisions at $\sqrt{s}=8\mathrm{TeV}$ with the CMS detector at the LHC. The data set corresponds to an integrated luminosity of $19.7{\mathrm{fb}}^{-1}$. In a search for narrow resonances that couple to quark-quark, quark-gluon, or gluon-gluon pairs, model-independent upper limits, at 95% confidence level, are obtained on the production cross section of resonances, with masses above 1.2 TeV. When interpreted in the context of specific models the limits exclude string resonances with masses below 5.0 TeV; excited quarks below 3.5 TeV; scalar diquarks below 4.7 TeV; $W^{\prime }$ bosons below 1.9 TeV or between 2.0 and 2.2 TeV; $Z^{\prime }$ bosons below 1.7 TeV; and Randall-Sundrum gravitons below 1.6 TeV. A separate search is conducted for narrow resonances that decay to final states including $b$ quarks. The first exclusion limit is set for excited $b$ quarks, with a lower mass limit between 1.2 and 1.6 TeV depending on their decay properties. Searches are also carried out for wide resonances, assuming for the first time width-to-mass ratios up to 30%, and for quantum black holes with a range of model parameters. The wide resonance search excludes axigluons and colorons with mass below 3.6 TeV, and color-octet scalars with mass below 2.5 TeV. Lower bounds between 5.0 and 6.3 TeV are set on the masses of quantum black holes.

We propose Drinfeld’s second realization of the quantum group relevant to the Lax-operator approach developed in the work of Bazhanov, Frassek, Lukowski, Meneghelli and Staudacher.

We study a massless scalar field in ${\mathrm{AdS}}_{d+1}$ with a nonlinear coupling ${\varphi }^N$ and not limited to spherical symmetry. The free-field-eigenstate spectrum is strongly resonant, and it is commonly believed that the nonlinear coupling leads to energy transfer between eigenstates. We prove that when $Nd$ is even, the most efficient resonant channels to transfer energy are always absent. In particular, for $N=3$ this means no energy transfer at all. For $N=4$, this effectively kills half of the channels, leading to the same set of extra conservation laws recently derived for gravitational interactions within spherical symmetry.

We prove that adiabatic regularization and DeWitt-Schwinger point-splitting provide the same result when renormalizing expectation values of the stress-energy tensor for spin-$1/2$ fields. This generalizes the equivalence found for scalar fields, which is here recovered in a different way. We also argue that the coincidence limit of the DeWitt-Schwinger proper time expansion of the two-point function agrees exactly with the analogous expansion defined by the adiabatic regularization method at any order (for both scalar and spin-$1/2$ fields). We also illustrate the power of the adiabatic method to compute higher order DeWitt coefficients in Friedmann-Lemaître-Robertson-Walker Universes.

We study the interior of distorted stationary rotating black holes on the example of a Kerr black hole distorted by external static and axisymmetric mass distribution. We show that there is a duality transformation between the outer and inner horizons of the black hole, which is different from that of an electrically charged static distorted black hole. The duality transformation is directly related to the discrete symmetry of the space-time. The black hole horizon areas, surface gravity, and angular momentum satisfy the Smarr formula constructed for both the horizons. We formulate the zeroth, the first, and the second laws of black hole thermodynamics for both the horizons of the black hole and show the correspondence between the local and the global forms of the first law. The Smarr formula and the laws of thermodynamics formulated for both the horizons are related by the duality transformation. The distortion is illustrated on the example of a quadrupole and octupole fields. The distortion fields noticeably affect the proper time of a free fall from the outer to the inner horizon of the black hole along the symmetry semiaxes. There is some minimal nonzero value of the quadrupole and octupole moments when the time becomes minimal. The minimal proper time indicates the closest approach of the horizons due to the distortion.

We study some aspects of cosmological evolution in a universe described by a viable curvature corrected exponential $F(R)$ gravity model, in the presence of matter fluids consisting of collisional matter and radiation. Particularly, we express the Friedmann-Robertson-Walker equations of motion in terms of parameters that are appropriate for describing the dark energy oscillations and compare the dark energy density and the dark energy equation of state parameter corresponding to collisional and noncollisional matter. In addition to these, and owing to the fact that the cosmological evolution of collisional and noncollisional matter universes, when quantified in terms of the Hubble parameter and the effective equation of states parameters, is very much alike, we further scrutinize the cosmological evolution study by extending the analysis to the study of matter perturbations in the matter domination era. We quantify this analysis in terms of the growth factor of matter perturbations, in which case the resulting picture of the cosmological evolution is clear, since collisional and noncollisional universes can be clearly distinguished. Interestingly enough, since it is known that the oscillations of the effective equation of state parameter around the phantom divide are undesirable and unwanted in $F(R)$ gravities, when these are considered for redshifts near the matter domination era and before, in the curvature corrected exponential model with collisional matter that we study here there exist oscillations that never cross the phantom divide. Therefore, this rather unwanted feature of the effective equation of state parameter is also absent in the collisional matter filled universe.

We derive a map between Einstein spaces of positive and negative curvature, including scalar matter. Starting from a space of positive curvature with some dimensions compactified on a sphere and analytically continuing the number of compact dimensions, we obtain a space of negative curvature with a compact hyperbolic subspace, and vice versa. Prime examples of such spaces are de Sitter (dS) and anti–de Sitter (AdS) space, as well as black hole spacetimes with (A)dS asymptotics and perturbed versions thereof, which play an important role in holography. This map extends work done by Caldarelli et al., who map asymptotically AdS spaces to Ricci-flat ones. A remarkable result is that the boundary of asymptotically AdS spaces is mapped to a brane in the bulk of de Sitter, and perturbations near the AdS boundary are sourced by a stress tensor confined to this brane. We also calculate the Brown-York stress tensor for the perturbed AdS metric, which turns out to be the negative of the stress tensor on the de Sitter brane. The map can also be used as a solution generator, and we obtain a Kerr/AdS solution with hyperbolic horizon from a known Kerr/dS one.

We discuss the possibility of localizing Einstein gravity on a three-brane embedded in a five-dimensional Minkowski space by giving a space-dependent mass to the graviton. We show that, with an overall fine tuning of the mass profile, it is possible to localize a massless graviton with a finite mass gap from the massive Kaluza-Klein modes. The theory does not contain ghosts and no scalar massless mode is sourced by brane matter. A massless vector mode is strongly coupled to the flux of energy momentum into the extra dimension, so that it is not sourced as long as only brane-localized matter is considered. In the case where the mass profile has a deltalike shape, the four-dimensional Planck mass $M_4$ is related to the five-dimensional one, $M_5$, by $M_4^2=M_5^3/m_0$, where $m_0$ is the mass of the first Kaluza-Klein mode of the graviton.

Bajc-Melfo ($\mathbf{BM}$) two-field ($S,\varphi$) superpotentials define metastable F-term supersymmetry-breaking vacua suitable as hidden sectors for calculable and realistic family and grand unification models. The undetermined vacuum expectation value (VEV) $⟨S_s⟩$ of the Polonyi field that breaks supersymmetry can be fixed either by coupling to $N=1$ supergravity or by radiative corrections. $\mathbf{BM}$ hidden sectors extend to symmetric multiplets $(S,\varphi {)}_{ab}$ of a gauged $O(N_g)$ family symmetry, broken at the GUT scale, so that the $O(N_g)$ charged component VEVs $⟨{\widehat{S}}_{ab}⟩$ are also undetermined before accounting for the $O(N_g)$ D-terms, which fix them by cancellation against D-term contributions from the visible sector. This facilitates Yukawon ultraminimal GUTs (YUMGUTs) proposed in [C. S. Aulakh and C. K. Khosa, Phys. Rev. D 90, 045008 (2014)] by relieving the visible sector from the need to give null D-terms for the family symmetry $O(N_g)$. We analyze symmetry breaking and spectra of the hidden-sector fields in the supergravity resolved case when $N_g=1,2,3$. Besides the Polonyi field $S_s$, most of the superfields ${\widehat{S}}_{ab}$ remain light, with fermions getting masses only from loop corrections. Such modes may yield novel dark matter lighter than 100 GeV. Possible Polonyi and moduli problems associated with the fields $S_{ab}$ call for detailed investigation of loop effects due to the Yukawa and gauge interactions in the hidden sector and of postinflationary field relaxation dynamics.

As is well known, the search for and eventual identification of dark matter in supersymmetry requires a simultaneous, multipronged approach with important roles played by the LHC as well as both direct and indirect dark matter detection experiments. We examine the capabilities of these approaches in the 19-parameter phenomenological MSSM which provides a general framework for complementarity studies of neutralino dark matter. We summarize the sensitivity of dark matter searches at the 7 and 8 (and eventually 14) TeV LHC, combined with those by Fermi, CTA, IceCube/DeepCore, COUPP, LZ and XENON. The strengths and weaknesses of each of these techniques are examined and contrasted and their interdependent roles in covering the model parameter space are discussed in detail. We find that these approaches explore orthogonal territory and that advances in each are necessary to cover the supersymmetric weakly interacting massive particle parameter space. We also find that different experiments have widely varying sensitivities to the various dark matter annihilation mechanisms, some of which would be completely excluded by null results from these experiments.

We perform a nonperturbative lattice calculation of the complex phase and modulus of the pion form factor in the timelike momentum region using the finite-volume technique. We use two ensembles of $2+1$-flavor overlap fermions at pion masses $m_{\pi }=380$ and 290 MeV. By calculating the $I=1$ correlators in the center-of-mass and three moving frames, we obtain the form factor at ten different values of the timelike momentum transfer around the vector resonance. We compare the results with the phenomenological model of Gounaris-Sakurai and its variant.

The fact that analyses of semi-inclusive deep inelastic scattering suggest that the polarized strange quark density $\mathrm{\Delta }s(x)+\mathrm{\Delta }\overline{s}(x)$ is positive in the measured region of Bjorken $x$, whereas all analyses of inclusive deep inelastic scattering yield significantly negative values of this quantity, is known as the “strange quark polarization puzzle.” We have analyzed the world data on inclusive deep inelastic scattering, including the COMPASS 2010 proton data on the spin asymmetries, and for the first time, the new extremely precise JLab CLAS data on the proton and deuteron spin structure functions. Despite allowing, in our parametrization, for a possible sign change, our results confirm that the inclusive data yield significantly negative values for the polarized strange quark density.

The recoil retardation effect in the $K^{-}d$ scattering length is studied. Using the nonrelativistic effective field theory approach, it is demonstrated that a systematic perturbative expansion of the recoil corrections in the parameter $\xi =M_K/m_N$ is possible in spite of the fact that $K^{-}d$ scattering at low energies is inherently nonperturbative due to the large values of the $\overline{K}N$ scattering lengths. The first-order correction to the $K^{-}d$ scattering length due to single insertion of the retardation term in the multiple-scattering series is calculated. The recoil effect turns out to be reasonably small even at the physical value of $M_K/m_N\simeq 0.5$.

We map the parameter space for minimal supersymmetric Standard Model neutralino dark matter which freezes out to the observed relic abundance, in the limit that all superpartners except the neutralinos and charginos are decoupled. In this space of relic neutralinos, we show the dominant dark matter annihilation modes, the mass splittings among the electroweakinos, direct detection rates, and collider cross sections. The mass difference between the dark matter and the next-to-lightest neutral and charged states is typically much less than electroweak gauge boson masses. With these small mass differences, the relic neutralino surface is accessible to a future 100 TeV hadron collider, which can discover interneutralino mass splittings down to 1 GeV and thermal relic dark matter neutralino masses up to 1.5 TeV with a few inverse attobarns of luminosity. This coverage is a direct consequence of the increased collider energy: in the Standard Model events with missing transverse momentum in the TeV range have mostly hard electroweak radiation, distinct from the soft radiation shed in compressed electroweakino decays. We exploit this kinematic feature in final states including photons and leptons, tailored to the 100 TeV collider environment.