The interiors of high mass compact (neutron) stars may contain deconfined quark matter in a crystalline color-superconducting (CCS) state. On a basis of microscopic nuclear and quark matter equations of states we explore the internal structure of such stars in general relativity. We find that their stable sequence harbors CCS quark cores with masses $M_{\mathrm{core}}\le (0.78–0.82)M_{\odot }$ and radii $R_{\mathrm{core}}\le 7\mathrm{km}$. The CCS quark matter can support nonaxisymmetric deformations, because of its finite shear modulus, and can generate gravitational radiation at twice the rotation frequency of the star. Assuming that the CCS core is maximally strained we compute the maximal quadrupole moment it can sustain. The characteristic strain of gravitational wave emission $h_0$ predicted by our models are compared to the upper limits obtained by the LIGO and GEO 600 detectors. The upper limits are consistent with the breaking strain of CCS matter $\sigma \le {10}^{-4}$ and large pairing gaps $\Delta \sim 50\mathrm{MeV}$, or, alternatively, with $\sigma \sim {10}^{-3}$ and small pairing gaps $\Delta \sim 15\mathrm{MeV}$. An observationally determined value of the characteristic strain $h_0$ can pin down the product $\sigma {\Delta }^2$. On the theoretical side a better understanding of the breaking strain of CCS matter will be needed to predict reliably the level of the deformation of CCS quark core from first principles.

The corrections induced by light quark masses to the current algebra result for the ${\pi }^0$ lifetime are reexamined. We consider next-to-next-to-leading order corrections and we compute all the one-loop and the two-loop diagrams which contribute to the decay amplitude at this order in the two-flavor chiral expansion. We show that the result is renormalizable, as Weinberg consistency conditions are satisfied. We find that chiral logarithms are present at this order unlike the case at next-to-leading order. The result could be used in conjunction with lattice QCD simulations, the feasibility of which was recently demonstrated. We discuss the matching between the two-flavor and the three-flavor chiral expansions in the anomalous sector at order one-loop and derive the relations between the coupling constants. A modified chiral counting is proposed, in which $m_s$ counts as $O(p)$. We have updated the various inputs needed and used this to make a phenomenological prediction.

We present a QCD analysis of the neutral current (NC) neutrino-nucleus interaction at the small-$x$ region using the color dipole formalism. This phenomenological approach is quite successful in describing experimental results in deep inelastic $ep$ scattering and charged current neutrino-nucleus interactions at high energies. We present theoretical predictions for the relevant structure functions and the corresponding implications for the total NC neutrino cross section. It is shown that at small $x$, the NC boson-nucleon cross section should exhibit the geometric scaling property that has important consequences for ultrahigh energy neutrino phenomenology.

This paper presents experimental requirements to determine the neutrino mass hierarchy using reactor neutrinos. The detector shall be located at a baseline around 58 km from the reactor(s) to measure the energy spectrum of electron antineutrinos (${\overline{\nu }}_e$) precisely. By applying Fourier cosine and sine transforms to the L/E spectrum, features of the neutrino mass hierarchy can be extracted from the $|\Delta m_{31}^2|$ and $|\Delta m_{32}^2|$ oscillations. To determine the neutrino mass hierarchy above 90% probability, requirements to the baseline, the energy resolution, the energy scale uncertainty, the detector mass, and the event statistics are studied at different values of ${sin}^2(2{\theta }_{13})$.

The level of holographic noise expected to be observed in interferometric gravitational wave detectors such as GEO600 is reexamined. It is demonstrated that earlier estimates are based on assumed linear diffractive behavior of Planck radiation. Since nonlinear effects, such as self-focusing, are expected to appear at much lower energies, the expected level of holographic noise must be reduced by many orders of magnitude.

We study in detail deep inelastic scattering in the ’t Hooft model. We are able to analytically check current conservation and to obtain analytic expressions for the matrix elements with relative precision $\mathcal{O}(1/Q^2)$ for $1-x\gg {\beta }^2/Q^2$. This allows us to compute the electron-meson differential cross section and its moments with $1/Q^2$ precision. For the former we find maximal violations of quark-hadron duality, as it is expected for a large $N_c$ analysis. For the latter we find violations of the operator product expansion at next-to-leading order in the $1/Q^2$ expansion.

We investigate the Lagrangian terms of scalar-gauge interactions in a weakly coupled gauge theory beyond the ultraviolet momentum cutoff of models where the collective symmetry breaking mechanism protects the Higgs mass squared against having quadratic divergence. We also propose a five-dimensional model in which the gauge symmetry breaking is achieved by boundary conditions consistent with local gauge transformations. It is shown that the scalar-gauge operators in the two models differ in the absence of quadratic divergence.

The description of the inspiral of a stellar-mass compact object into a massive black hole sitting at a galactic center is a problem of major relevance for the future space-based gravitational-wave observatory Laser Interferometer Space Antenna (LISA), as the signals from these systems will be buried in the data stream and accurate gravitational-wave templates will be needed to extract them. The main difficulty in describing these systems lies in the estimation of the gravitational effects of the stellar-mass compact object on his own trajectory around the massive black hole, which can be modeled as the action of a local force, the self-force. In this paper, we present a new time-domain numerical method for the computation of the self-force in a simplified model consisting of a charged scalar particle orbiting a nonrotating black hole. We use a multidomain framework in such a way that the particle is located at the interface between two domains so that the presence of the particle and its physical effects appear only through appropriate boundary conditions. In this way we eliminate completely the presence of a small length scale associated with the need of resolving the particle. This technique also avoids the problems associated with the impact of a low differentiability of the solution in the accuracy of the numerical computations. The spatial discretization of the field equations is done by using the pseudospectral collocation method and the time evolution, based on the method of lines, uses a Runge-Kutta solver. We show how this special framework can provide very efficient and accurate computations in the time domain, which makes the technique amenable for the intensive computations required in the astrophysically relevant scenarios for LISA.

We investigate the generation of gravitational waves due to the gravitational instability of primordial density perturbations in an early matter-dominated era which could be detectable by experiments such as laser interferometer gravitational wave observatory (LIGO) and laser interferometer space antenna (LISA). We use relativistic perturbation theory to give analytic estimates of the tensor perturbations generated at second order by linear density perturbations. We find that large enhancement factors with respect to the naive second-order estimate are possible due to the growth of density perturbations on sub-Hubble scales. However very large enhancement factors coincide with a breakdown of linear theory for density perturbations on small scales. To produce a primordial gravitational-wave background that would be detectable with LIGO or LISA from density perturbations in the linear regime requires primordial comoving curvature perturbations on small scales of order 0.02 for advanced LIGO or 0.005 for LISA; otherwise numerical calculations of the nonlinear evolution on sub-Hubble scales are required.

The mesonic excitations and $s$-wave $\pi \mathrm{\text{−}}\pi$ scattering lengths at finite temperature are studied in the two-flavor Polyakov–Nambu–Jona-Lasinio (PNJL) model. The masses of the $\pi$ and $\sigma$ mesons, pion-decay constant, the pion-quark coupling strength, and the scattering lengths $a_0$ and $a_2$ at finite temperature are calculated in the PNJL model with two forms of Polyakov-loop effective potential. The obtained results are almost independent of the choice of the effective potentials. The calculated results in the PNJL model are also compared with those in the conventional Nambu–Jona-Lasinio model and indicate that the effect of color confinement screens the effect of temperature below the critical one in the PNJL model. Furthermore, the Goldberger-Treiman relation and the Gell-Mann–Oakes–Renner relation are extended to the case at finite temperature in the PNJL model.

Nonuniversal boundary conditions in grand unified theories can lead to nonuniversal gaugino masses at the unification scale. In $R$-parity preserving theories the lightest supersymmetric particle is a natural candidate for the dark matter. The composition of the lightest neutralino and the identity of the next-to-lightest supersymmetric particle are studied, when nonuniversal gaugino masses come from representations of SO(10). In these cases, the thermal relic density compatible with the Wilkinson Microwave Anisotropy Probe observations is found. Relic densities are compared with the universal case. Mass spectra in the studied cases are discussed.

The concept of spin-directed momentum provides a useful and restrictive framework for describing dynamical mechanisms that can lead to single-spin observables. The value of this framework can be demonstrated by consideration of the polarizing fracture functions, ${\Delta }^N{M}_{B\uparrow /p}^q(x,z,k_{TN};Q^2)$, that characterize the production of polarized baryons in the target fragmentation region of semi-inclusive deep-inelastic scattering from an unpolarized target. When Bjorken $x$ is chosen large enough to indicate a hard scattering from a valence quark, the fracture function formalism dynamically selects a quark-diquark basis for baryon structure. Attention to constituent orbital angular momentum in the formation process and its role in contributing to the transverse momentum of the produced baryon illustrates important aspects of the generation of polarization observables.

This work deals with bifurcation and pattern changing in models described by two real scalar fields. We consider generic models with quartic potentials and show that the number of independent polynomial coefficients affecting the ratios between the various domain wall tensions can be reduced to 4 if the model has a superpotential. We then study specific one-parameter families of models and compute the wall tensions associated with both Bogomol’nyi-Prasad-Sommerfield (BPS) and non-BPS sectors. We show how bifurcation can be associated to modification of the patterns of domain wall networks and illustrate this with some examples which may be relevant to describe realistic situations of current interest in high energy physics. In particular, we discuss a simple solution to the cosmological domain wall problem.

We give a general analysis of AdS boundary conditions for spin-$3/2$ Rarita-Schwinger fields and investigate boundary conditions preserving supersymmetry for a graviton multiplet in ${\mathrm{AdS}}_4$. Linear Rarita-Schwinger fields in ${\mathrm{AdS}}_d$ are shown to admit mixed Dirichlet-Neumann boundary conditions when their mass is in the range $0\le |m|<1/2l_{\mathrm{AdS}}$. We also demonstrate that mixed boundary conditions are allowed for larger masses when the inner product is “renormalized” accordingly with the action. We then use the results obtained for $|m|=1/l_{\mathrm{AdS}}$ to explore supersymmetric boundary conditions for $\mathcal{N}=1$ ${\mathrm{AdS}}_4$ supergravity in which the metric and Rarita-Schwinger fields are fluctuating at the boundary. We classify boundary conditions that preserve boundary supersymmetry or superconformal symmetry. Under the AdS/CFT dictionary, Neumann boundary conditions in $d=4$ supergravity correspond to gauging the superconformal group of the three-dimensional CFT describing M2-branes, while $\mathcal{N}=1$ supersymmetric mixed boundary conditions couple the CFT to $\mathcal{N}=1$ superconformal topologically massive gravity.

General higher-dimensional rotating black hole spacetimes of any dimensions admit the Killing and Killing-Yano tensors, which generate the hidden symmetries just as in four-dimensional Kerr spacetime. We study these properties of the black holes using the formalism of supersymmetric mechanics of pseudoclassical spinning point particles. We present two nontrivial supercharges, corresponding to the Killing-Yano and conformal Killing-Yano tensors of the second rank. We demonstrate that an unusual extended Poisson-Dirac algebra of these supercharges results in two independent Killing tensors in spacetime dimensions $D\ge 6$, giving explicit examples for the Myers-Perry black holes in $D=6$ dimensions.

We extend the investigation of the recently proposed Kerr/conformal field theory correspondence to large classes of rotating black hole solutions in gauged and ungauged supergravities. The correspondence, proposed originally for four-dimensional Kerr black holes, asserts that the quantum states in the near-horizon region of an extremal rotating black hole are holographically dual to a two-dimensional chiral theory whose Virasoro algebra arises as an asymptotic symmetry of the near-horizon geometry. In fact, in dimension $D$ there are [$(D-1)/2$] commuting Virasoro algebras. We consider a general canonical class of near-horizon geometries in arbitrary dimension $D$, and show that in any such metric the [$(D-1)/2$] central charges each imply, via the Cardy formula, a microscopic entropy that agrees with the Bekenstein-Hawking entropy of the associated extremal black hole. In the remainder of the paper we show for most of the known rotating black hole solutions of gauged supergravity, and for the ungauged supergravity solutions with four charges in $D=4$ and three charges in $D=5$, that their extremal near-horizon geometries indeed lie within the canonical form. This establishes that, in all these examples, the microscopic entropies of the dual conformal field theories agree with the Bekenstein-Hawking entropies of the extremal rotating black holes.

We analyze the dark matter problem in the context of the supersymmetric $U(1{)}_{B-L}$ model. In this model, the lightest neutralino can be the $B-L$ gaugino ${\tilde{Z}}_{B-L}$ or the extra Higgsinos ${\tilde{\chi }}_{1,2}$ dominated. We compute the thermal relic abundance of these particles and show that, unlike the lightest neutralino in the MSSM, they can account for the observed relic abundance with no conflict with other phenomenological constraints. The prospects for their direct detection, if they are part of our galactic halo, are also discussed.

Supernatural inflation is an attractive model based on just a flat direction with soft supersymmetry breaking mass terms in the framework of supersymmetry. The beauty of the model is that it needs no fine-tuning. However, the prediction of the spectral index is $n_s\gtrsim 1$, in contrast to experimental data. In this paper, we discuss supernatural inflation with the spectral index reduced to $n_s=0.96$ without any fine-tuning, considering the general feature that a flat direction is lifted by a nonrenormalizable term with an $A$-term.

Using a unified approach of optical-mechanical analogy in a semiclassical formula, we evaluate the effect of Chern-Simons modified gravity on the quantum phase shift of de Broglie waves in neutron interferometry. The phase shift calculated here reveals, in a single equation, a combination of effects coming from Newtonian gravity, inertial forces, Schwarzschild and Chern-Simons modified gravity. However the last two effects, though new, turn out to be too tiny to be observed, and hence only of academic interest at present. The approximations, wherever used, as well as the drawbacks of the nondynamical approach are clearly indicated.

Starting from a covariant formalism of the Sunyaev-Zeldovich effect for the thermal and nonthermal distributions, we derive the frequency redistribution function identical to Wright’s method assuming the smallness of the photon energy (in the Thomson limit). We also derive the redistribution function in the covariant formalism in the Thomson limit. We show that two redistribution functions are mathematically equivalent in the Thomson limit, which is fully valid for the cosmic microwave background photon energies. We will also extend the formalism to the kinematical Sunyaev-Zeldovich effect. With the present formalism we will clarify the situation for the discrepancy existed in the higher-order terms of the kinematical Sunyaev-Zeldovich effect.