We compute the renormalized expectation value of the square of a quantum scalar field on a Reissner-Nordström–de Sitter black hole in which the temperatures of the event and cosmological horizons are equal (“lukewarm” black hole). Our numerical calculations for a thermal state at the same temperature as the two horizons indicate that this renormalized expectation value is regular on both the event and cosmological horizons. We are able to show analytically, using an approximation for the field modes near the horizons, that this is indeed the case.

We study production of Kaluza-Klein (KK) gluons at the Large Hadron Collider (LHC) in the framework of a warped extra dimension with the standard model fields propagating in the bulk. We show that the detection of the KK gluon is challenging since its production is suppressed by small couplings to the proton’s constituents. Moreover, the KK gluon decays mostly to top pairs due to an enhanced coupling and hence is broad. Nevertheless, we demonstrate that for $M_{\mathrm{KKG}}\lesssim 4\mathrm{TeV}$, $100{\mathrm{fb}}^{-1}$ of data at the LHC can provide discovery of the KK gluon. We utilize a sizable left-right polarization asymmetry from the KK gluon resonance to maximize the signal significance, and we explore the novel feature of extremely highly energetic “top-jets.” We briefly discuss how the detection of electroweak gauge KK states ($Z/W$) faces a similar challenge since their leptonic decays (golden modes) are suppressed. Our analysis suggests that other frameworks, for example, little Higgs, which rely on UV completion via strong dynamics might face similar challenges, namely, (1) suppressed production rates for the new particles (such as $Z^{\prime }$), due to their “light-fermion-phobic” nature, and (2) difficulties in detection since the new particles are broad and decay predominantly to third generation quarks and longitudinal gauge bosons.

The DAMA Collaboration has recently analyzed its data of the extensive WIMP direct search (DAMA/NaI) which detected an annual modulation, by taking into account the channeling effect which occurs when an ion traverses a detector with a crystalline structure. Among possible implications, this Collaboration has considered the case of a coherent weakly interacting massive particle (WIMP)-nucleus interaction and then derived the form of the annual modulation region in the plane of the WIMP-nucleon cross section versus the WIMP mass, using a specific modeling for the channeling effect. In the present paper we first show that light neutralinos fit the annual modulation region also when channeling is taken into account. To discuss the connection with indirect signals consisting in galactic antimatter, in our analysis we pick up a specific galactic model, the cored isothermal-sphere. In this scheme we determine the sets of supersymmetric models selected by the annual modulation regions and then prove that these sets are compatible with the available data on galactic antiprotons. We comment on implications when other galactic distribution functions are employed. Finally, we show that future measurements on galactic antiprotons and antideuterons will be able to shed further light on the populations of light neutralinos singled out by the annual modulation data.

Electroweak one-loop calculations for production of top-quark pairs at colliders are completed by providing the missing QED type contributions from real and virtual photons, where also effects from interference between QED and QCD contributions have to be taken into account. Moreover, photon-induced $t\overline{t}$ production is included as another partonic channel.

The baryon decay modes of $B$, $\overline{B}\to N_1{\overline{N}}_2(f)$, ${\overline{N}}_1{N}_2(\overline{f})$ provide a frame work to test $CP$-invariance in baryon sector. It is shown that in the rest frame of $B$, $N_1$ and ${\overline{N}}_2$ come out with longitudinal polarization ${\lambda }_1={\lambda }_2=\pm 1$ with decay width ${\Gamma }_f={\Gamma }_f^{++}+{\Gamma }_f^{--}$ and the asymmetry parameter ${\alpha }_f=\Delta {\Gamma }_f=({\Gamma }_f^{++}-{\Gamma }_f^{--})/{\Gamma }_f$. It is shown that $CP$ invariance prediction ${\alpha }_f=-{\overline{\alpha }}_{\overline{f}}$ can be tested in these decay modes; especially in the time-dependent decays of $B_q^0-{\overline{B}}_q^0$ complex. Apart from this, it is shown that decay modes $B(\overline{B})\to N_1{\overline{N}}_2({\overline{N}}_1{N}_2)$ and subsequent nonleptonic decays of $N_2$, ${\overline{N}}_2$ or $(N_1,{\overline{N}}_1)$ into hyperon (antihyperon) also provide a frame work to study $CP$-odd observables in hyperon decays.

We extend the Polyakov-loop improved Nambu–Jona-Lasinio model to $2+1$ flavor case to study the chiral and deconfinement transitions of strongly interacting matter at finite temperature and nonzero chemical potential. The Polyakov loop, the chiral susceptibility of light quarks ($u$ and $d$), and the strange quark number susceptibility as functions of temperature at zero chemical potential are determined and compared with the recent results of lattice QCD simulations. We find that there is always an inflection point in the curve of strange quark number susceptibility accompanying the appearance of the deconfinement phase, which is consistent with the result of lattice QCD simulations. Predictions for the case at nonzero chemical potential and finite temperature are made as well. We give the phase diagram in terms of the chemical potential and temperature and find that the critical end point moves down to low temperature and finally disappears with the decrease of the strength of the ’t Hooft flavor-mixing interaction.

We study the consequences of CPT and lepton number violation in the neutrino sector. For CPT violation we take gravity with which neutrino and antineutrino couple differently. Gravity mixes neutrino and antineutrino in an unequal ratio to give two mass eigenstates. Lepton number violation interaction together with CPT violation gives rise to neutrino-antineutrino oscillation. Subsequently, we study the neutrino flavor mixing and oscillation under the influence of gravity. It is found that gravity changes flavor oscillation significantly which influences the relative abundance of different flavors in present universe. We show that the neutrinoless double beta decay rate is modified due to the presence of gravity—the origin of CPT violation, as the mass of the flavor state is modified.

Within the superfield approach, we prove the absence of UV/IR mixing in the three-dimensional noncommutative supersymmetric Maxwell-Chern-Simons theory at any loop order and demonstrate its finiteness in one, three, and higher loop orders.

We show that the pathology which afflicts the Hartle-Hawking vacuum on the Kerr black hole space-time can be regarded as due to rigid rotation of the state with the horizon in the sense that, when the region outside the speed-of-light surface is removed by introducing a mirror, there is a state with the defining features of the Hartle-Hawking vacuum. In addition, we show that, when the field is in this state, the expectation value of the energy-momentum stress tensor measured by an observer close to the horizon and rigidly rotating with it corresponds to that of a thermal distribution at the Hawking temperature rigidly rotating with the horizon.

We model two mergers of orbiting binary neutron stars, the first forming a black hole and the second a differentially rotating neutron star. We extract gravitational waveforms in the wave zone. Comparisons to a post-Newtonian analysis allow us to compute the orbital kinematics, including trajectories and orbital eccentricities. We verify our code by evolving single stars and extracting radial perturbative modes, which compare very well to results from perturbation theory. The Einstein equations are solved in a first-order reduction of the generalized harmonic formulation, and the fluid equations are solved using a modified convex essentially non-oscillatory method. All calculations are done in three spatial dimensions without symmetry assumptions. We use the had computational infrastructure for distributed adaptive mesh refinement.

We construct the conserved charges (mass and angular momentum) of the Chern-Simons modified general relativity in asymptotically flat and anti-de Sitter (AdS) spacetimes. Our definition is based on background Killing symmetries and reduces to the known expressions in the proper limits.

We study the anti–de Sitter/conformal field theory correspondence with boundary conditions ${\mathrm{AdS}}_5\times {\mathbf{S}}^5/{\mathbb{Z}}_k$, where the ${\mathbb{Z}}_k$ acts freely but breaks all supersymmetry. While there are closed string tachyons at small ’t Hooft coupling, there are no tachyons at large coupling. Nevertheless, we show that there is a nonperturbative instability directly analogous to the decay of the Kaluza-Klein vacuum. We discuss the implications of this instability for the strongly coupled dual field theory, and compare with earlier studies of this theory at weak coupling.

We develop a Hamiltonian formalism of braneworld gravity, which singles out two preferred, mutually orthogonal directions. One is a unit twist-free field of spatial vectors with integral lines intersecting perpendicularly the brane. The other is a temporal vector field with respect to which we perform the Arnowitt-Deser-Misner decomposition of the Einstein-Hilbert Lagrangian. The gravitational variables arise from the projections of the spatial metric and their canonically conjugated momenta as tensorial, vectorial and scalar quantities defined on the family of hypersurfaces containing the brane. They represent the gravitons, a gravi-photon, and a gravi-scalar, respectively. From the action we derive the canonical evolution equations and the constraints for these gravitational degrees of freedom both on the brane and outside it. By integrating across the brane, the dynamics also generates the tensorial and scalar projection of the Lanczos equation. The vectorial projection of the Lanczos equation arises in a similar way from the diffeomorphism constraint. Both the graviton and the gravi-scalar are continuous across the brane, however the momentum of the gravi-vector has a jump, related to the energy transport (heat flow) on the brane.

We have compiled a data set consisting of 22 data points at a redshift range (0.15, 3.8) which can be used to constrain the linear perturbation growth rate $f=\frac{d\ln \delta }{d\ln a}$. Five of these data points constrain directly the growth rate $f$ through either redshift distortions or change of the power spectrum with redshift. The rest of the data points constrain $f$ indirectly through the rms mass fluctuation ${\sigma }_8(z)$ inferred from $L_y\mathrm{\text{−}}\alpha$ at various redshifts. Our analysis tests the consistency of the $\Lambda \mathrm{CDM}$ model and leads to a constraint of the Wang-Steinhardt growth index $\gamma$ [defined from $f={\Omega }_m(a{)}^{\gamma }$] as $\gamma ={0.67}_{-0.17}^{+0.20}$. This result is clearly consistent at $1\sigma$ with the value $\gamma =\frac{6}{11}=0.545$ predicted by $\Lambda \mathrm{CDM}$. We also apply our analysis on a new null test of $\Lambda \mathrm{CDM}$ which is similar to the one recently proposed by Chiba and Nakamura (arXiv:0708.3877) but does not involve derivatives of the expansion rate $H(z)$. This also leads to the fact that $\Lambda \mathrm{CDM}$ provides an excellent fit to the current linear growth data.

We investigate the influence of the fourth-generation quarks on the asymmetries for unpolarized and polarized leptons in $B\to K^{*}{\ell }^{+}{\ell }^{-}$ decay. We obtain that for both ($\mu$, $\tau$) channels the magnitudes of the differential forward-backward (FB) asymmetries and the average forward-backward asymmetries are quite sensitive to the fourth-generation quarks’ mass and mixing parameters. We also achieve that, among the double lepton polarization FB asymmetries, just longitudinally polarized leptons’ FB asymmetry shows considerable discrepancy with respect to the third-generation standard model. Moreover, we find that longitudinally polarized leptons’ FB asymmetry and its variation with new fourth-generation standard model parameters coincide with unpolarized FB when the lepton mass vanishes. The study of FB asymmetries can serve as a good tool to search for new-physics effects, precisely, to search for the fourth-generation quarks ($t^{\prime }$, $b^{\prime }$) via its indirect manifestations in the loop diagrams.

We have studied the lepton flavor violating processes $\mu \to e\gamma$ and $\mu -e$ conversion in nuclei induced by unparticle. Both $\mathrm{Br}(\mu \to e\gamma )$ and the $\mu -e$ conversion rate $\mathrm{CR}(\mu -e,\mathrm{Nuclei})$ strongly depend on the scale dimension $d_{\mathcal{U}}$ and the unparticle coupling ${\lambda }_{\mathrm{K}}^{f{f}^{\prime }}$ ($\mathrm{K}=\mathrm{V}$, A, S, P). Present experimental upper bounds on $\mathrm{Br}(\mu \to e\gamma )$, $\mathrm{CR}(\mu -e,\mathrm{Ti})$, and $\mathrm{CR}(\mu -e,\mathrm{Au})$ put stringent constraints on the parameters of unparticle physics. The scale dimensions $d_{\mathcal{U}}$ around 2 are favored for the unparticle scale ${\Lambda }_{\mathcal{U}}$ of $\mathcal{O}(10\mathrm{TeV})$ and the unparticle coupling of $\mathcal{O}({10}^{-3})$. $\mathrm{CR}(\mu -e,\mathrm{Nuclei})$ is proportional to ${\mathrm{Z}}_{\mathrm{eff}}^4{\mathrm{A}}^2/\mathrm{Z}$ for the pure vector and scalar couplings between unparticle and SM fermions; this peculiar atomic number dependence can be used to distinguish unparticle from other theoretical models.

Within the frameworks of the light-front quark model (LFQM) and chiral perturbation theory (ChPT) of $O(p^6)$, we reevaluate the form factors of the $K^{+}\to \gamma$ transition. We use these form factors to study the decay of $K^{+}\to e^{+}{\nu }_e\gamma$, which is dominated by the structure-dependent contribution. We show the differential decay branching ratio as a function of $x=2E_{\gamma }/m_K$, where $E_{\gamma }(m_K)$ is the photon energy (kaon mass). Explicitly, we find that, in the standard model with the cut of $x=0.01$ (0.1), the decay branching ratio of $K^{+}\to e^{+}{\nu }_e\gamma$ is $1.54(1.44)\times {10}^{-5}$ and $1.57(1.47)\times {10}^{-5}$ in the LFQM and ChPT, respectively.

Using $58\times {10}^6$ $J/\psi$ events collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider, the decays $J/\psi \to \gamma \varphi \rho$ and $J/\psi \to \gamma \omega \rho$ are searched for, and upper limits on their branching fractions are reported at the 90% C.L. No clear structures are observed in the $\gamma \rho$, $\gamma \varphi$, or $\rho \varphi$ mass spectra for $J/\psi \to \gamma \varphi \rho$ nor in the $\gamma \rho$, $\gamma \omega$, or $\rho \omega$ mass spectra for $J/\psi \to \gamma \omega \rho$.