It is known that there is no three-dimensional analog of de Sitter black holes. I show that the analog does exist when non-Gaussian (i.e., ring-type) smearings of point matter hairs are considered. This provides a new way of constructing black hole solutions from hairs. I find that the obtained black hole solutions are quite different from the usual large black holes in that there are (i) large to small black hole transitions which may be considered as inverse Hawking-Page transitions and (ii) solitonlike (i.e., nonperturbative) behaviors. For Gaussian smearing, there is no black hole but a gravastar solution exists.

We explore the possibility of improving the $\Lambda \mathrm{CDM}$ model at megaparsec scales by introducing a scalar interaction that increases the mutual gravitational attraction of dark matter particles. Using N-body simulations, we study the spatial distribution of dark matter particles and halos. We measure the effect of modifications in the Newton’s gravity on properties of the two-point correlation function, the dark matter power spectrum, the cumulative halo mass function, and density probability distribution functions. The results look promising: the scalar interactions produce desirable features at megaparsec scales without spoiling the $\Lambda \mathrm{CDM}$ successes at larger scales.

Northern hemisphere TeV gamma-ray observatories such as Milagro and Tibet $\mathrm{AS}\gamma$ have demonstrated the importance of all-sky instruments by discovering previously unidentified sources that may be the PeVatrons producing cosmic rays up to the knee in the cosmic ray spectrum. We evaluate the potential of IceCube to identify similar sources in the southern sky by detailing an analytic approach to determine fluxes of muons from TeV gamma-ray showers. We apply this approach to known gamma-ray sources such as supernova remnants. We find that, similar to Milagro, detection is possible in 10 years for pointlike PeVatrons with fluxes stronger than several ${10}^{-11}$ particles ${\mathrm{TeV}}^{-1}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$.

We investigate the IceCube detection potential of very high energy neutrinos from blazars, for different classes of hadronic models, taking into account the limits imposed on the neutrino flux by the recent Fermi telescope observations. Assuming the observed $\gamma$-ray emission is produced by the decay of neutral pions from proton-proton interactions, the measurement of the time-averaged spectral characteristics of blazars in the GeV energy band imposes upper limits on the time-averaged neutrino flux. Comparing these upper limits to the $5\sigma$ discovery threshold of IceCube for different neutrino spectra and different source locations in the sky, we find that several BL Lacs with hard spectra in the GeV band are within the detection potential of IceCube. If the $\gamma$-ray emission is dominated by the neutral pion decay flux, none of the flat-spectrum radio quasars are detectable with IceCube. If the primary high energy proton spectrum is very hard and/or neutrinos are produced in proton photon, rather than proton-proton reactions, the upper limit on the neutrino flux imposed by the measured $\gamma$-ray spectra is relaxed and gamma-ray observations impose only lower bounds on the neutrino flux. We investigate whether these lower bounds guarantee the detection of blazars with very hard neutrino spectra (spectral index ${\Gamma }_{\nu }\sim 1$), expected in the latter type model. We show that all the hadronic models of activity of blazars are falsifiable with IceCube. Furthermore, we show that models with $\gamma$-ray emission produced by the decay of neutral pions from proton-proton interactions can be readily distinguished from the models based on proton-gamma interactions and/or models predicting very hard high energy proton spectra via a study of the distribution of spectral indices of $\gamma$-ray spectra of sources detected with IceCube.

We use two-flavor heavy baryon chiral perturbation theory to investigate the isovector axial charges of the spin one-half hyperons. Expressions for these hyperon axial charges are derived at next-to-leading order in the chiral expansion. We utilize phenomenological and lattice QCD inputs to assess the convergence of the two-flavor theory, which appears to be best for cascades.

LHC searches for new physics focus on combinations of hard physics objects. In this work we propose a qualitatively different soft signal for new physics at the LHC—the “anomalous underlying event.” Every hard LHC event will be accompanied by a soft underlying event due to QCD and pileup effects. Though it is often used for QCD and Monte Carlo studies, here we propose the incorporation of an underlying event analysis in some searches for new physics. An excess of anomalous underlying events may be a smoking-gun signal for particular new physics scenarios such as “quirks” or “hidden valleys” in which large amounts of energy may be emitted by a large multiplicity of soft particles. We discuss possible search strategies for such soft diffuse signals in the tracking system and calorimetry of the LHC experiments. We present a detailed study of the calorimetric signal in a concrete example, a simple quirk model motivated by folded supersymmetry. In these models the production and radiative decay of highly excited quirk bound states leads to an “antenna pattern” of soft unclustered energy. Using a dedicated simulation of a toy detector and a multipole analysis familiar in cosmic microwave background studies, we compare the signal to the expected backgrounds.

Witten’s twistor string theory gives rise to an enigmatic formula [1] known as the “connected prescription” for tree-level Yang-Mills scattering amplitudes. We derive a link representation for the connected prescription by Fourier transforming it to mixed coordinates in terms of both twistor and dual twistor variables. We show that it can be related to other representations of amplitudes by applying the global residue theorem to deform the contour of integration. For six and seven particles we demonstrate explicitly that certain contour deformations rewrite the connected prescription as the Britto-Cachazo-Feng-Witten representation, thereby establishing a concrete link between Witten’s twistor string theory and the dual formulation for the $S$ matrix of the $\mathcal{N}=4$ SYM recently proposed by Arkani-Hamed et al. Other choices of integration contour also give rise to “intermediate prescriptions.” We expect a similar though more intricate structure for more general amplitudes.

We describe an efficient scheme for evaluating higher order contributions to primordial cosmological perturbations using the “in-in” formalism, which is the basis of modern calculations of non-Gaussian and higher order contributions to the primordial spectrum. We show that diagrams with two or more vertices require careful handling. We present an implementation of the operator formalism in which these diagrams can be evaluated in a simple and transparent fashion. We illustrate our methodology by evaluating the correction to the primordial gravitational wave spectrum generated by scalar loops, a 2-vertex, 1-loop interaction. We then look at a generalized $N$-point, 2-vertex diagram.

We calculate the phase diagram of two-flavor quark matter within the Nambu–Jona-Lasinio (NJL) model in the temperature-flavor asymmetry plane in the case where there are three competing phases: the homogeneous Bardeen-Cooper-Schrieffer (BCS) phase, the unpaired phase, and a phase with broken spatial symmetry, which is here taken to be the counterpart of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase in condensed matter physics. The system belongs to the universality class of paramagnetic-ferromagnetic-helical systems, and therefore contains a tricritical Lifshitz point in its phase diagram, where the momentum scale characterizing the breaking of translational invariance has a critical exponent of $1/2$ to leading order. Upon varying the coupling constant of the theory we find that in weak coupling, the FFLO phase is favored at arbitrary flavor asymmetries for sufficiently low temperatures; at intermediate coupling its occupancy domain is shifted towards larger asymmetries. Strong coupling features a new regime of an inhomogeneous FF state, which we identify with a current-carrying Bose-Einstein condensate of tightly bound up and down quarks. The temperature and asymmetry dependence of the gap function is studied. It is shown that the anomalous temperature dependence of the gap in the homogeneous, flavor-asymmetric phase is transformed into a normal dependence (self-similar to the BCS phase) at arbitrary coupling, once the FF phase is allowed for. We analyze the occupation numbers and the Cooper-pair wave function and show that when the condensate momentum is orthogonal to the particle momentum the minority component contains a blocking region (breach) around the Fermi sphere in the weak-coupling limit, which engulfs more low-momentum modes as the coupling is increased, and eventually leads to a topological change in strong coupling, where the minority Fermi sphere contains either two occupied strips or an empty sphere. For nonorthogonal momenta, the blocking region is either reduced or extinct, i.e., no topological changes are observed.

The relativistic flux tube model is an effective description of confined quarks and gluons in which the confining interaction is carried by the flux tube, a Nambu-Goto string. We first show that the relativistic flux tube model can be applied to glueballs seen as bound states of transverse constituent gluons. After a comparison of that approach with usual spinless Salpeter Hamiltonians, we compute glueball masses and decay widths. Comments about the $\eta \mathrm{\text{−}}{\eta }^{\prime }$-pseudosclar glueball problem, the glueball–Pomeron conjecture, and finite-temperature effects are finally given. We also point out the existence of a duality between open and closed flux tube models of glueballs.

Using an effective Lagrangian approach, we perform a model-independent analysis of the interactions among electroweak gauge bosons and the third generation quarks, i.e. the $Wtb$, $Zt\overline{t}$, and $Zb\overline{b}$ couplings. After one imposes the known experimental constraint on the $Z{b}_L{b}_L$ coupling, we show that the electroweak $SU(2{)}_L\times U(1{)}_Y$ symmetry of the standard model specifies the pattern of deviations of the $Z{t}_L{t}_L$ and $W{t}_L{b}_L$ couplings, independent of underlying new physics scenarios. We study implications of the predicted pattern with data on the single top quark and $Zt\overline{t}$ associated production processes at the Large Hadron Collider. Such an analysis could in principle allow for a determination of the $Wtb$ coupling without prior knowledge of $|V_{tb}|$, which is otherwise difficult to achieve.

We examine the prospect to measure the Higgs boson mass using the recently introduced kinematic variable, the $M_{T2}$-assisted on-shell (MAOS) momentum, that provides a systematic approximation to the invisible neutrino momenta in dileptonic decays of a $W$-boson pair. For this purpose, we introduce a modified version of the MAOS momentum that is applicable even when one or both of the $W$-bosons from the Higgs decay are in off shell. It is demonstrated that the MAOS Higgs mass distribution, constructed with the MAOS neutrino momenta, shows a clear peak at the true Higgs boson mass when an event cut selecting higher value of $M_{T2}$ is employed. We perform the likelihood analysis for this MAOS mass distribution to determine the Higgs boson mass, and find it can improve the accuracy of the Higgs mass measurement. Our results indicate that the MAOS Higgs mass can also be useful for the discovery or exclusion of the Higgs boson in certain mass range.

We give a comprehensive presentation of methods for calculating the Casimir force to arbitrary accuracy, for any number of objects, arbitrary shapes, susceptibility functions, and separations. The technique is applicable to objects immersed in media other than vacuum, nonzero temperatures, and spatial arrangements in which one object is enclosed in another. Our method combines each object’s classical electromagnetic scattering amplitude with universal translation matrices, which convert between the bases used to calculate scattering for each object, but are otherwise independent of the details of the individual objects. The method is illustrated by rederiving the Lifshitz formula for infinite half-spaces, by demonstrating the Casimir-Polder to van der Waals crossover, and by computing the Casimir interaction energy of two infinite, parallel, perfect metal cylinders either inside or outside one another. Furthermore, it is used to obtain new results, namely, the Casimir energies of a sphere or a cylinder opposite a plate, all with finite permittivity and permeability, to leading order at large separation.

We derive a formalism of numerical relativity for higher-dimensional spacetimes and develop numerical codes for simulating a wide variety of five-dimensional (5D) spacetimes for the first time. First, the Baumgarte-Shapiro-Shibata-Nakamura formalism is extended for arbitrary spacetime dimensions $D\ge 4$, and then, the so-called cartoon method, which was originally proposed as a robust method for simulating axisymmetric 4D spacetimes, is described for 5D spacetimes of several types of symmetries. Implementing 5D numerical relativity codes with the cartoon methods, we perform test simulations by evolving a 5D Schwarzschild spacetime and a 5D spacetime composed of a gravitational-wave packet of small amplitude. The numerical simulations are stably performed for a sufficiently long time, as done in the 4D case, and the obtained numerical results agree well with the analytic solutions: The numerical solutions are shown to converge at the correct order. We also confirm that a long-term accurate evolution of the 5D Schwarzschild spacetime is feasible using the so-called puncture approach. In addition, we derive the Landau-Lifshitz pseudotensor in arbitrary dimensions, and show that it gives a robust tool for computing the energy flux of gravitational waves. The formulations and methods developed in this paper provide a powerful tool for studying nonlinear dynamics of higher-dimensional gravity.

We generalize Bowen-York black hole initial data to hyperboloidal constant mean curvature slices which extend to future null infinity. We solve this initial value problem numerically for several cases, including unequal mass binary black holes with spins and boosts. The singularity at null infinity in the Hamiltonian constraint associated with a constant mean curvature hypersurface does not pose any particular difficulties. The inner boundaries of our slices are minimal surfaces. Trumpet configurations are explored both analytically and numerically.

The effects of perturbative Lorentz and $CPT$ violation on neutrino oscillations are studied. Features include neutrino-antineutrino oscillations, direction dependence, and unconventional energy behavior. Leading-order corrections arising from renormalizable operators are derived in the general three-flavor effective field theory. The results are applied to neutrino-beam experiments with long baselines, which offer excellent sensitivity to the accompanying effects. Key signatures of Lorentz and $CPT$ violation using neutrino beams include sidereal variations in the oscillation probabilities arising from the breakdown of rotational symmetry, and $CPT$ asymmetries comparing neutrino and antineutrino modes. Attainable sensitivities to coefficients for Lorentz violation are estimated for several existing and future experiments.

We study the use of final state particle pseudorapidity for measurements of $s$-channel resonances at the LHC. Distinguishing the spin of an $s$-channel resonance can, in principle, be accomplished using angular distributions in the center-of-mass frame, possibly using a center-edge asymmetry measurement, $A_{\mathrm{CE}}$. In addition, forward-backward asymmetry measurements, $A_{\mathrm{FB}}$, can be used to distinguish between models of extra neutral gauge bosons. In this article we show how these measurements can be improved by using simple methods based on the pseudorapidity of the final state particles and present the expected results for $A_{\mathrm{FB}}$ and $A_{\mathrm{CE}}$ for several representative models.

We investigate the three flavor Nambu–Jona-Lasinio model of neutral quark matter at zero temperature and finite density, taking into account the scalar, the pseudoscalar, and the Kobayashi-Maskawa-’t Hooft interactions as well as the repulsive vector plus axial-vector interaction terms (vector extended Nambu—Jona-Lasinio). We focus on the effect of the vector interaction on the chiral restoration at finite density in neutral matter. We also study the evolution of the charged pseudoscalar meson energies as a function of the quark chemical potential.

We present a quantitative study of energy flow away from jets by numerically solving the evolution equation derived by Banfi, Marchesini, and Smye, and apply the result to two processes at the LHC: discriminating high-$p_t$ jets originating from decays of heavy electroweak bosons from the QCD background, and the survival probability of the BFKL-initiated dijet rapidity gaps. As a by-product, we find a hidden symmetry of the Banfi, Marchesini, and Smye equation which is a remnant of conformal symmetry.

We derive the threshold-resummed total cross section for heavy quark production in hadronic collisions accurate to next-to-next-to-leading logarithm, employing recent advances on soft anomalous dimension matrices for massive pair production in the relevant kinematic limit. We also derive the relation between heavy quark threshold resummations for fixed pair kinematics and the inclusive cross section. As a check of our results, we have verified that they reproduce all poles of the color-averaged $q\overline{q}\to t\overline{t}$ amplitudes at two loops, noting that the latter are insensitive to the color-antisymmetric terms of the soft anomalous dimension.