The thermodynamic quantities such as the local temperature, heat capacity, off-shell free energy, and the stability of a black hole involving a global monopole within or outside the $f(R)$ gravity are examined. We compare the two classes of results to show the influence from the generalization of the general relativity. It is found that the $f(R)$ theory will modify the thermodynamic properties of black holes, but the shapes of curves for thermodynamic quantities with respect to the horizon are similar to the results within the frame of general relativity. In both cases, there will exist a small black hole which will decay and a large stable black hole in the case that the temperatures are higher than their own critical temperature.

We study gravitational waves emitted in the late inspiral stage of binary neutron stars by analyzing the wave form obtained in numerical-relativity simulations. For deriving the physical gravitational wave forms from the numerical results, the resolution extrapolation plays an essential role for our simulations. The extrapolated gravitational-wave phases are compared with those calculated in the post-Newtonian (PN) and effective-one-body (EOB) formalisms including corrections of tidal effects. We show that the extrapolated gravitational-wave phases in numerical relativity agree well with those by the PN and EOB calculations for most of the inspiral stage except for a tidally dominated, final inspiral stage, in which the PN and EOB results underestimate the tidal effects. Nevertheless, the accumulated phase difference between our extrapolated results and the results by the PN/EOB calculations is at most 1–3 radian in the last 15 cycles.

We discuss two possible extensions to the standard model in which an inert singlet scalar state that only interacts with the Higgs boson is added together with some fermions. In one model, the fermions provide for a seesaw mechanism for the neutrino masses; in the other model, for grand unification of the gauge couplings. Masses and interaction strengths are fixed by the requirement of controlling the finite one-loop corrections to the Higgs boson mass, thus addressing the little hierarchy problem. The inert scalar could provide a viable dark matter candidate. Direct detection of this scalar singlet in nuclear scattering experiments is possible with a cross section within reach of future experiments.

In a recent paper, we proposed a hierarchical ansatz for the lepton-number-violating trilinear Yukawa couplings of the $R$-parity-violating minimal supersymmetric standard model. As a result, the number of free parameters in the lepton-number-violating sector was reduced from 36 to 6. Neutrino oscillation data fixes these six parameters, which also uniquely determines the decay modes of the lightest supersymmetric particle and thus governs the collider signature at the LHC. A typical signature of our model consists of multiple leptons in the final state and significantly reduced missing transverse momentum compared to models with $R$-parity conservation. In this work, we present exclusion limits on our model based on multilepton searches performed at the Large Hadron Collider with a 7 TeV center-of-mass energy in 2011 while accommodating a 125 GeV Higgs.

We derive the off-shell photon propagator and fermion-photon vertex at one-loop level in Maxwell-Chern-Simons quantum electrodynamics in arbitrary covariant gauge, using four-component spinors with parity-even and parity-odd mass terms for both fermions and photons. We present our results using a basis of two, three and four point integrals, some of them not known previously in the literature. These integrals are evaluated in arbitrary space-time dimensions so that we reproduce results derived earlier under certain limits.

The impact-parameter dependent saturation model (IP-Sat) is a simple dipole model that incorporates key features of the physics of gluon saturation and matches smoothly to the perturbative QCD dipole expression at large $Q^2$ for a given $x$. It was previously shown that the model gives a good description of HERA data suggesting evidence for gluon saturation effects at small $x$. The model has also been applied to proton-proton and proton-nucleus collisions and provides the basis for the IP-Glasma model of initial conditions in heavy ion collisions. Here we present a reanalysis of available data in electron-proton collisions at small Bjorken $x$, including the recently released combined data from the ZEUS and H1 collaborations. We first confront the model to the high precision combined data for the reduced cross section and obtain its parameters. With these parameters fixed, we compare model results to the data for the structure function $F_2$, the longitudinal structure function $F_L$, the charm structure function $F_2^{c\overline{c}}$, exclusive vector meson ($J/\psi$, $\varphi$ and $\rho$) production, and deeply virtual Compton scattering. Excellent agreement is obtained for the processes considered at small $x$ in a wide range of $Q^2$. Our results strongly hint at universality of the IP-Sat dipole amplitude and the extracted impact-parameter distribution of the proton. They also provide a benchmark for further refinements in studies of QCD saturation at colliders.

Induced by three gluons symmetry, Mandelstam variables $s$, $t$, $u$ symmetric expressions are widely involved in collider physics, especially in heavy quarkonium physics. In this work we study the general form of $s$, $t$, $u$ symmetric polynomials, and find that they can be expressed as polynomials where the symmetry is manifest. The general form is then used to simplify expressions which asymptotically reduces the length of original expression to one-sixth. Based on the general form, we reproduce the exact differential cross section of $J/\psi$ hadron production at leading order in $v^2$ up to four unknown constant numbers by simple analysis. Furthermore, we prove that differential cross section at higher order in $v^2$ is proportional to that at leading order. This proof explains the proportion relation at next-to-leading order in $v^2$ found in previous work and generalizes it to all order.

Results are reported from a search for the effects of contact interactions using events with a high-mass, oppositely charged muon pair. The events are collected in proton-proton collisions at $\sqrt{s}=7\mathrm{TeV}$ using the Compact Muon Solenoid detector at the Large Hadron Collider. The data sample corresponds to an integrated luminosity of $5.3{\mathrm{fb}}^{-1}$. The observed dimuon mass spectrum is consistent with that expected from the standard model. The data are interpreted in the context of a quark- and muon-compositeness model with a left-handed isoscalar current and an energy scale parameter $\Lambda$. The 95% confidence level lower limit on $\Lambda$ is 9.5 TeV under the assumption of destructive interference between the standard model and contact-interaction amplitudes. For constructive interference, the limit is 13.1 TeV. These limits are comparable to the most stringent ones reported to date.

We study vortexlike solutions to the Lifshitz-Chern-Simons theory. We find that such solutions exist and have a logarithmically divergent energy, which suggests that a Kostelitz-Thouless transition may occur, in which voxtex-antivortex pairs are created above a critical temperature. Following a suggestion made by Callan and Wilzcek for the global $U(1)$ scalar field model, we study vortex solutions of the Lifshitz-Chern-Simons model formulated on the hyperbolic plane, finding that, as expected, the resulting configurations have finite energy. For completeness, we also explore Lifshitz-Chern-Simons vortex solutions on the sphere.

Wide area cosmological surveys enable investigation of whether dark energy properties are the same in different directions on the sky. Cosmic microwave background observations strongly restrict any dynamical effects from anisotropy, in an integrated sense. For more local constraints we compute limits from simulated distance measurements for various distributions of survey fields in a Bianchi I anisotropic universe. We then consider the effects of fitting for line of sight properties where isotropic dynamics is assumed (testing the accuracy through simulations) and compare sensitivities of observational probes for anisotropies, from astrophysical systematics as well as dark energy. We also point out some interesting features of anisotropic expansion in Bianchi I cosmology.

We consider dynamics of space-time volume-filling form fields with “wrong sign” kinetic terms, such as in so-called type-II* string theories. Locally, these form fields are just additive renormalizations of the cosmological constant. They have no fluctuating degrees of freedom. However, once the fields are coupled to membranes charged under them, their configurations are unstable: by a process analogous to Schwinger pair production the field space-filling flux increases. This reduces the cosmological constant and preserves the null energy condition, since the processes that can violate it by reducing the form flux are very suppressed. The increase of the form flux implies that as time goes on the probability for further membrane nucleation increases, in contrast to the usual case where the field approaches its vacuum value and ceases to induce further transitions. Thus, in such models spaces with tiny positive vacuum energy are ultimately unstable, but the instability may be slow and localized. In a cosmological setting, this instability can enhance black hole rate formation, by locally making the vacuum energy negative at late times, which constrains the scales controlling membrane dynamics, and may even collapse a large region of the visible Universe.

The angular power spectrum of the cosmic microwave background temperature anisotropies is a good probe for looking into the primordial density fluctuations at large scales in the Universe. Here we reexamine the angular power spectrum of the Wilkinson Microwave Anisotropy Probe data, paying particular attention to the fine structures (oscillations) at $\ell =100–150$ reported by several authors. Using Monte Carlo simulations, we confirm that the gap from the simple power law spectrum is a rare event, about $2.5–3\sigma$, if these fine structures are generated by experimental noise and cosmic variance. Next, in order to investigate the origin of the structures, we examine frequency and direction dependences of the fine structures by dividing the observed QUV frequency maps into four sky regions. We find that the structures around $\ell \sim 120$ do not have significant dependences either on frequencies or direction. For the structure around $\ell \sim 140$, however, we find that the characteristic signature found in the all-sky power spectrum is attributed to the anomaly only in the southeast region.

In the framework of nonlocal SU(2) chiral quark models with Polyakov loop, we analyze the dependence of the deconfinement and chiral restoration critical temperatures on the explicit chiral symmetry breaking driven by the current quark mass. Our results are compared with those obtained within the standard local Polyakov-Nambu-Jona-Lasinio model and with lattice QCD calculations. For a wide range of pion masses, it is found that both deconfinement and chiral restoration critical temperatures turn out to be strongly entangled, in contrast with the corresponding results within the Polyakov-Nambu-Jona-Lasinio model. In addition, it is seen that the growth of the critical temperatures with the pion mass above the physical point is basically linear, with a slope parameter that is close to the existing lattice QCD estimates. On the other hand, we find a tendency to favor an early onset of the first order transition expected in the large quark mass limit.

We study the evolution of quantum fluctuations in the glasma, created immediately after the collision of heavy nuclei. We show how the presence of instabilities leads to an enhancement of nonlinear interactions among initially small fluctuations. The nonlinear dynamics leads to an enhanced growth of fluctuations in a large momentum region, exceeding by far the originally unstable band. We investigate the dependence on the coupling constant at weak coupling using classical statistical lattice simulations for $SU(2)$ gauge theory and show how these nonlinearities can be analytically understood within the framework of two-particle irreducible effective action techniques. The dependence on the coupling constant is only logarithmic, in accordance with analytic expectations. Concerning the isotropization of bulk quantities, our results indicate that the system exhibits an order-one anisotropy on parametrically large time scales. Despite this fact, we find that gauge invariant pressure correlation functions seem to exhibit a power law behavior characteristic for wave turbulence.

The possible existence of short-range forces between unpolarized and polarized spin-$\frac{1}{2}$ particles has attracted the attention of physicists for decades. These forces are predicted in various theories and provide a possible new source for parity and time-reversal symmetry violation. We use an ensemble of polarized ${}^3\mathrm{He}$ gas in a cell with a $250\mathrm{\text{−}}\mu \mathrm{m}$ thick glass window to search for a force from pseudoscalar boson exchange over sub-millimeter ranges. This interaction would produce an NMR frequency shift as an unpolarized mass is moved near and far from the polarized ensemble. We report a new upper bound with a factor of 10–30 improvement on the product $g_s{g}_p^n$ of the scalar couplings to the fermions in the unpolarized mass, and the pseudoscalar coupling of the polarized neutron in the ${}^3\mathrm{He}$ nucleus for force ranges from ${10}^{-4}$ to ${10}^{-2}\mathrm{m}$, which corresponds to a mass range of $2\times {10}^{-3}$ to $2\times {10}^{-5}\mathrm{eV}$ for the pseudoscalar boson. This represents the most sensitive search that sets a direct limit on the important “axion window.”

We study the effects of introducing purely gravitational Chern-Simons Lagrangian terms in ordinary Einstein gravity on stationary rotating black hole solutions and on the associated thermodynamical properties, in a generic number of dimensions which support these terms (i.e., in $D=4k-1$). We analyze the conditions, namely the number of vanishing angular momenta, under which the contributions of the Chern-Simons term to the equations of motion and the black hole entropy vanish. The particular case of a seven-dimensional theory in which a purely gravitational Chern-Simons term is added to the Einstein-Hilbert Lagrangian in $D=7$ dimensions is investigated in some detail. As we have not been able to find exact analytic solutions in nontrivial cases, we turn to perturbation theory and calculate the first-order perturbative correction to the Myers-Perry metric in the case where all angular momenta are equal. The expansion parameter is a dimensionless combination linear in the Chern-Simons coupling constant and the angular momentum. Corrections to horizon and ergosurface properties, as well as black hole entropy and temperature, are presented.

In this paper, we consider the problem of computing the self-force and self-energy for a static scalar charge in a wormhole space-time with throat profile $r(\rho )=\sqrt{{\rho }^2+a^2}$ for arbitrary coupling of the field to the curvature. This calculation has previously been considered numerically by Bezerra Khusnutdinovand [Phys. Rev. D 79, 064012 (2009)], while analytic results have been obtained in the special cases of minimal ($\xi =0$) coupling [N. R. Khusnutdinov and I. V. Bakhmatov, Phys. Rev. D 76, 124015 (2007)] and conformal coupling [V. B. Bezerra and N. R. Khusnutdinov Phys. Rev. D 79, 064012 (2009)] ($\xi =1/8$ in three dimensions). We present here a closed form expression for the static Green’s function for arbitrary coupling and hence we obtain an analytic expression for the self-force. The self-force depends crucially on the coupling of the field to the curvature of the space-time and hence it is useful to determine the dependence explicitly. The numerical computation can identify some qualitative aspects of this dependence such as the change in the sign of the force as it passes through the conformally coupled value, as well as the fact that the self-force diverges for $\xi =1/2$. From the closed form expression, it is straightforward to see that there is an infinite set of values of the coupling constant for which the self-force diverges, but we also see that there is an infinite set of values for which the self-force vanishes.

Precise understanding of nonlinear evolution of cosmological perturbations during inflation is necessary for the correct interpretation of measurements of non-Gaussian correlations in the cosmic microwave background and the large-scale structure of the Universe. The “$\delta N$ formalism” is a popular and powerful technique for computing nonlinear evolution of cosmological perturbations on large scales. In particular, it enables us to compute the curvature perturbation $\zeta$ on large scales without actually solving perturbed field equations. However, people often wonder why this is the case. In order for this approach to be valid, the perturbed Hamiltonian constraint and matter-field equations on large scales must, with a suitable choice of coordinates, take on the same forms as the corresponding unperturbed equations. We find that this is possible when (1) the unperturbed metric is given by a homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker metric; and (2) on large scales and with a suitable choice of coordinates, one can ignore the shift vector ($g_{0i}$) as well as time dependence of tensor perturbations to $g_{ij}/a^2(t)$ of the perturbed metric. While the first condition has to be assumed a priori, the second condition can be met when (3) the anisotropic stress becomes negligible on large scales. However, in order to explicitly show that the second condition follows from the third condition, one has to use gravitational field equations, and thus this statement may depend on the details of the theory of gravitation. Finally, as the $\delta N$ formalism uses only the Hamiltonian constraint and matter-field equations, it does not a priori respect the momentum constraint. We show that the error in the momentum constraint only yields a decaying mode solution for $\zeta$, and the error vanishes when the slow-roll conditions are satisfied.

The effective theory for baryons with combined $1/N_c$ and chiral expansions is analyzed for nonstrange baryons. Results for baryon masses and axial couplings are obtained in the small scale expansion, to be coined as the $\xi$ expansion, in which the $1/N_c$ and the low energy power countings are linked according to $1/N_c=\mathcal{O}(\xi )=\mathcal{O}(p)$. Masses and axial couplings are analyzed to $\mathcal{O}({\xi }^3)$ and $\mathcal{O}({\xi }^2)$, respectively, which correspond to next-to-next to leading order evaluations, and require one-loop contributions in the effective theory. The spin-flavor approximate symmetry, a consequence of the large $N_c$ limit in baryons, plays a very important role in the real world with $N_c=3$ as shown by the analysis of its breaking in the masses and the axial couplings. Applications to the recent lattice QCD results on baryon masses and the nucleon’s axial coupling are presented. It is shown that those results are naturally described within the effective theory at the order considered in the $\xi$ expansion.

An analysis is given of the decay $\tau \to \mu +\gamma$ in minimal supersymmetric standard model extensions with a vectorlike generation. Here mixing with the mirrors allows the possibility of this decay. The analysis is done at one loop with the exchange of charginos and neutralinos and of sleptons and mirror sleptons in the loops. It is shown that a branching ratio $\mathcal{B}(\tau \to \mu \gamma )$ in the range $4.4\times {10}^{-8}-{10}^{-9}$ can be gotten which would be accessible to improved experiment such as at SuperB factories for this decay. The effects of $CP$ violation on this decay are also analyzed.