We construct odd-dimensional extremal charged black hole solutions with a twisted ${\mathrm{S}}^1$ as an extra dimension on generalized Euclidean Taub-NUT spaces. There exists a null hypersurface where an expansion for an outgoing null geodesic congruence vanishes, then these spacetimes look like black holes. We show that the metrics admit ${\mathrm{C}}^0$ extension across the horizon, but some components of Riemann curvature diverge there if the dimension is higher than five. The singularity is relatively mild so that an observer along a free-fall geodesic can traverse the horizon. We also show solutions with a positive cosmological constant.

We study the critical phenomena of Kerr-AdS black hole. Phase structures are observed at different temperatures, $T_L$, $T_{c1}$ and $T_{c2}$ with various features. We discuss the thermal stability considering the isothermal compressibility and how phase transitions related to each other. The asymptotic value of the angular momentum also has an implication on separating stable and unstable part. Near critical temperature $T_{c1}$, the order parameter is determined to calculate the critical exponents. All the critical exponents $(\alpha ,\beta ,\gamma ,\delta )=(0,\frac{1}{2},1,3)$ are identical to that of mean field systems. We plot the phase diagram near this critical point, and discuss the scaling symmetry of the free energy.

We examine various entropic inflation scenarios, under the light of eternality. After describing the inflation realization and the normal condition for inflation to last at the background level, we investigate the conditions for eternal inflation with the effect of thermal fluctuations produced from standard radiation and from the holographic screen. Furthermore, we incorporate stochastic quantum fluctuations through a phenomenological, Langevin analysis, studying whether they can affect the inflation eternality. In one-holographic-screen scenarios eternality can be easily obtained, while in double-screen considerations inflation is eternal only in the high-energy regime. Thus, from the cosmological point of view, one should take these into account before he can consider entropic gravity as a candidate for the description of nature. However, from the string theory point of view, inflation eternality may form the background for the “landscape” of string or M theory vacua, leading to new perspectives in entropy gravity.

Astrophysical black hole candidates are thought to be the Kerr black holes predicted by General Relativity, as these objects cannot be explained otherwise without introducing new physics. However, there is no observational evidence that the space-time around them is really described by the Kerr solution. The Kerr black hole hypothesis can be tested with the already available X-ray data by extending the continuum-fitting method, a technique currently used by astronomers to estimate the spins of stellar-mass black hole candidates. In general, we cannot put a constraint on possible deviations from the Kerr geometry, but only on some combination between these deviations and the spin. The measurement of the radio power of transient jets in black hole binaries can potentially break this degeneracy, thus allowing for testing the Kerr-nature of these objects.

We study the kinematics of deep inelastic scattering corresponding to the rotationally symmetric distribution of quark momenta in the nucleon rest frame. It is shown that rotational-symmetry together with Lorentz invariance can in leading order impose constraints on the quark intrinsic momenta. Obtained constraints are discussed and compared with the available experimental data.

The behavior of the Landau gauge gluon and ghost propagators is studied in pure $SU(3)$ gauge theory at nonzero temperature on the lattice. We concentrate on the momentum range (0.6, 2.0) GeV. For the longitudinal as well as for the transverse component of the gluon propagator we extract the continuum limit. We demonstrate the smallness of finite-size and Gribov-copy effects at temperatures close to the deconfinement phase transition at $T=T_c$ and within the restricted range of momenta. Since the longitudinal component $D_L(q)$ turns out to be most sensitive with respect to the phase transition, we propose some combinations of $D_L(q)$ signaling the transition much like “order parameters.”

We revisit the process $e^{+}{e}^{-}\to \gamma Z$ at the ILC with transverse beam polarization in the presence of anomalous $CP$-violating $\gamma ZZ$ coupling ${\lambda }_1$ and $\gamma \gamma Z$ coupling ${\lambda }_2$. We point out that if the final-state spins are resolved, then it becomes possible to fingerprint the anomalous coupling $\mathrm{Re}{\lambda }_1$. 90% confidence level limit on $\mathrm{Re}{\lambda }_1$ achievable at ILC with center-of-mass energy of 500 GeV or 800 GeV with realistic initial beam polarization and integrated luminosity is of the order of few times of ${10}^{-2}$ when the helicity of $Z$ is used and ${10}^{-3}$ when the helicity of $\gamma$ is used. The resulting corrections at quadratic order to the cross section and its influence on these limits are also evaluated and are shown to be small. The benefits of such polarization programmes at the ILC are compared and contrasted for the process at hand. We also discuss possible methods by which one can isolate events with a definite helicity for one of the final-state particles.

We have investigated nonstandard $\nu \overline{\nu }\gamma$ and $\nu \overline{\nu }\gamma \gamma$ couplings via $\nu \overline{\nu }$ production in a $\gamma p$ collision at the LHC. We obtain 95% confidence level bounds on $\nu \overline{\nu }\gamma$ and $\nu \overline{\nu }\gamma \gamma$ couplings by considering three different forward detector acceptances: $0.0015<\xi <0.15$, $0.0015<\xi <0.5$, and $0.1<\xi <0.5$. We show that the reaction $pp\to p\gamma p\to p\nu \overline{\nu }qX$ provides more than eight orders of magnitude improvement in neutrino-two photon couplings compared to LEP limits.

We revisit the bremsstrahlung process of a superluminal neutrino motivated by OPERA results. From a careful analysis of the plane-wave solutions of the superluminal neutrino, we find that the squared matrix elements contain additional terms from Lorentz violation due to the modified spin sum for the neutrino. We point out that the coefficients of the decay rate and the energy loss rate significantly depend on the details of the model, although the results are parametrically similar to the ones obtained by Cohen and Glashow [A. G. Cohen and S. L. Glashow, Phys. Rev. Lett. 107, 181803 (2011).]. We illustrate this from the modified neutral current interaction of neutrino with Lorentz violation of the same order as in the modified dispersion relation.

We present the cross section for production of a $Z$ boson in association with four jets at the Large Hadron Collider, at next-to-leading order in the QCD coupling. When the $Z$ decays to neutrinos, this process is a key irreducible background to many searches for new physics. Its computation has been made feasible through the development of the on-shell approach to perturbative quantum field theory. We present the total cross section for $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$, after folding in the decay of the $Z$ boson, or virtual photon, to a charged-lepton pair. We also provide distributions of the transverse momenta of the four jets, and we compare cross sections and distributions to the corresponding ones for the production of a $W$ boson with accompanying jets.

We show that the linearly polarized gluon distributions appear in the color dipole model as we derive the full cross sections of the DIS dijet production and the Drell-Yan dijet (${\gamma }^{*}$ jet correlation) process. Together with the normal Weizsäcker-Williams gluon distribution, the linearly polarized one will contribute to the DIS dijet production cross section as the coefficient of the $\cos (2\Delta \varphi )$ term in the correlation limit. We also derive the exact results for the cross section of the Drell-Yan dijet process, and find that the linearly polarized dipole gluon distribution which is identical to the normal dipole gluon distribution involves in the cross section. The results obtained in this paper agree with the previous transverse momentum dependent factorization study. We further derive the small-$x$ evolution of these linearly polarized gluon distributions and find that they rise as $x$ gets small at high energy.

Recently it was shown that vacuum in a background of a strong enough magnetic field becomes an electromagnetic superconductor due to interplay between strong and electromagnetic forces. The superconducting ground state of the vacuum is associated with a spontaneous emergence of quark-antiquark condensates which carry quantum numbers of charged $\rho$ mesons. The $\rho$-meson condensate is an inhomogeneous structure made of the so-called $\rho$ vortices, which are parallel to the magnetic field axis. The condensation of the charged $\rho$ mesons induces a (much weaker) superfluid-like condensate with quantum numbers of the neutral ${\rho }^{(0)}$ mesons. In this paper we show that the vortices in the superconducting condensate organize themselves in an equilateral triangular lattice similarly to an ordinary type-II superconductor. We show that each of these superconductor vortices is accompanied by three superfluid vortices and three superfluid antivortices made of the neutral $\rho$ meson condensate. The superconductor vortex overlaps with one of the superfluid vortices. The superposition of the superconductor and superfluid vortex lattices has a honeycomb pattern.

It is well known that large Hubble-induced supergravity corrections to the inflaton field can ruin the flatness of the potential, thus creating a tension between slow-roll inflation and supergravity. In this paper we show that it is possible to obtain a cosmologically flat direction, embedded within the minimal supersymmetric standard model, despite very large super-Hubble corrections. As an illustration, we show that a flat direction which is lifted by an $n=6$ operator matches the current cosmic microwave background data for a wide range of the Hubble parameter, ${10}^5\mathrm{GeV}\lesssim H_{inf}\lesssim {10}^{8.5}\mathrm{GeV}$. Our approach can be applied to any $F$-term inflationary model.

Based on recent work on simplicial diffeomorphisms in colored group field theories, we develop a representation of the colored Boulatov model, in which the group field theory (GFT) fields depend on variables associated to vertices of the associated simplicial complex, as opposed to edges. On top of simplifying the action of diffeomorphisms, the main advantage of this representation is that the GFT Feynman graphs have a different stranded structure, which allows a direct identification of subgraphs associated to bubbles, and their evaluation is simplified drastically. As a first important application of this formulation, we derive new scaling bounds for the regularized amplitudes, organized in terms of the genera of the bubbles, and show how the pseudomanifold configurations appearing in the perturbative expansion are suppressed as compared to manifolds. Moreover, these bounds are proved to be optimal.

In a recent work, a dual formulation of group field theories as noncommutative quantum field theories has been proposed, providing an exact duality between spin foam models and noncommutative simplicial path integrals for constrained BF theories. In light of this new framework, we define a model for four-dimensional gravity which includes the Immirzi parameter $\gamma$. It reproduces the Barrett-Crane amplitudes when $\gamma =\infty$, but differs from existing models otherwise; in particular, it does not require any rationality condition for $\gamma$. We formulate the amplitudes both as BF simplicial path integrals with explicit noncommutative $B$ variables, and in spin foam form in terms of Wigner $15j$ symbols. Finally, we briefly discuss the correlation between neighboring simplices, often argued to be a problematic feature, for example, in the Barrett-Crane model.

In F-term supergravity inflation models, scalar fields other than the inflaton generically receive a Hubble-induced mass, which may restore gauge symmetries during inflation and phase transitions may occur during or after inflation as the Hubble parameter decreases. We study monopole (and domain wall) production associated with such a phase transition in chaotic inflation in supergravity and obtain a severe constraint on the symmetry breaking scale which is related with the tensor-to-scalar ratio. Depending on model parameters, it is possible that monopoles are sufficiently diluted to be free from current constraints but still observable by planned experiments.

We describe cosmic gamma-ray and neutrino signals of dark matter annihilation, explaining how the complementarity of these signals provides additional information that, if observable, can enlighten the particle nature of dark matter. This is discussed in the context of exploiting the separate galactic and extragalactic components of the signal, using the spherical halo model distribution of dark matter. We motivate the discussion with supersymmetric extensions of the standard model of particle physics. We consider the minimal supersymmetric standard model (MSSM) where both neutrinos and gamma-rays are produced from annihilations. We also consider a gauged $B-L$, baryon number minus lepton number, extension of the MSSM, where annihilation can be purely to heavy right-handed neutrinos. We compare the galactic and extragalactic components of these signals, and conclude that it is not yet clear which may dominate when looking out of the galactic plane. To answer this question, we must have an understanding of the contribution of halo substructure to the annihilation signals. We find that different theories with indistinguishable gamma-ray signals can be distinguished in the neutrino signal. Gamma-ray annihilation signals are difficult to observe from the galactic center, due to abundant astrophysical sources; but annihilation neutrinos from there would not be so hidden, if they can be observed over the atmospheric neutrinos produced by cosmic rays.

Generating gaugino masses at the leading order has typically been difficult in direct/semidirect gauge mediated supersymmetry breaking models. The Komargodski-Shih (KS) theorem has established that local stability of the supersymmetry breaking vacuum implies a vanishing leading-order gaugino mass in generic renormalizable O’Raifeartaigh models. We relax the condition of renormalizability and investigate the possibility to evade the KS no-go theorem using higher dimensional operators in the Kähler potential and the superpotential. We demonstrate that higher dimensional terms which are polynomial in superfields are not adequate to evade the KS theorem. We narrow down on the possible class of nonpolynomial corrections that can induce unsuppressed gaugino mass in a global supersymmetry breaking vacuum. We find that these models are tantalizingly close to the theories obtained from strongly coupled supersymmetry breaking schemes.

We study $D$ meson resonances in hot, dense quark matter within the Nambu–Jona-Lasinio model and its Polyakov-loop extension. We show that the mass splitting between $D^{+}$ and $D^{-}$ mesons is moderate, not in excess of 100 MeV. When the decay channel into quasifree quarks opens (Mott effect) at densities above twice saturation density, the decay width reaches rapidly the value of 200 MeV which entails a spectral broadening sufficient to open $J/\psi$ dissociation processes. Contrary to results from hadronic mean-field theories, the chiral quark model does not support the scenario of a dropping $D$ meson masses so that scenarios for $J/\psi$ dissociation by quark rearrangement built on the lowering of the threshold for this process in a hot and dense medium have to be reconsidered and should account for the spectral broadening.