We report improved measurements of time-dependent $CP$ violation parameters for $B^0({\overline{B}}^0)\to \psi (2S)K_S^0$. This analysis is based on a data sample of $657\times {10}^6$ $B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB energy-asymmetric $e^{+}{e}^{-}$ collider. We fully reconstruct one neutral $B$ meson in the $\psi (2S)K_S^0$ $CP$-eigenstate decay channel, and the flavor of the accompanying $B$ meson is identified to be either $B^0$ or ${\overline{B}}^0$ from its decay products. $CP$ violation parameters are obtained from the asymmetries in the distributions of the proper-time intervals between the two $B$ decays: ${\mathcal{S}}_{\psi (2S)K_S^0}=+0.72\pm 0.09(\mathrm{stat})\pm 0.03(\mathrm{syst})$, ${\mathcal{A}}_{\psi (2S)K_S^0}=+0.04\pm 0.07(\mathrm{stat})\pm 0.05(\mathrm{syst})$. These results are in agreement with results from measurements of $B^0\to J/\psi K^0$.

We consider a variant of the Georgi-Glashow model in the Bogomol’nyi-Prasad-Sommerfield limit, augmented by a higher derivative Skyrme-like term, which is the simplest Yang-Mills-Higgs model that can support monopole bound states. The spherically symmetric solutions are studied with a combination of analytic and numerical techniques, which strongly suggest that the solutions converge to a finite energy configuration in the limit of infinite coupling of the Skyrme-like term.

We show that the main result of the recent paper by G. S. Adkins and J. McDonnell, Phys. Rev. D 75, 082001 (2007), the formula for the precession of Keplerian orbits induced by central-force perturbations, can be obtained very simply by the use of Hamilton’s vector.

We propose a manifestly U-duality invariant modular form for the $D^6{\mathcal{R}}^4$ interaction in the effective action of type IIB string theory compactified on $T^2$. It receives perturbative contributions up to genus three, as well as nonperturbative contributions from D-instantons and $(p,q)$ string instantons wrapping $T^2$. Our construction is based on constraints coming from string perturbation theory, U-duality, the decompactification limit to ten dimensions, and the equality of the perturbative part of the amplitude in type IIA and type IIB string theories. Using duality, parts of the perturbative amplitude are also shown to match exactly the results obtained from 11 dimensional supergravity compactified on $T^3$ at one loop. We also obtain parts of the genus one and genus $k$ amplitudes for the $D^{2k}{\mathcal{R}}^4$ interaction for arbitrary $k\ge 4$. We enhance a part of this amplitude to a U-duality invariant modular form.

We propose a manifestly U-duality invariant modular form for the $D^4{\mathcal{R}}^4$ interaction in type IIB string theory compactified on $T^2$. It receives perturbative contributions up to two loops, and nonperturbative contributions from D-instantons and $(p,q)$ string instantons wrapping $T^2$. We provide evidence for this modular form by showing that the coefficients at tree level and at one loop precisely match those obtained using string perturbation theory. Using duality, parts of the perturbative amplitude are also shown to match exactly the results obtained from 11 dimensional supergravity compactified on $T^3$ at one loop. Decompactifying the theory to nine dimensions, we obtain a U-duality invariant modular form, whose coefficients at tree level and at one loop agree with string perturbation theory.

Recent work in the literature had evaluated the energy-momentum tensor of a Casimir apparatus in a weak gravitational field, for an electromagnetic field subject to perfect conductor boundary conditions on parallel plates. The Casimir apparatus was then predicted to experience a tiny push in the upward direction, and the regularized energy-momentum tensor was evaluated to first order in the gravitational acceleration. This analysis made it desirable to assess what happens in a simpler case. For this purpose, the present paper studies a free, real massless scalar field subject to homogeneous Dirichlet conditions on the parallel plates. Working again to first order in the constant gravity acceleration, the resulting regularized and renormalized energy-momentum tensor is found to be covariantly conserved, while the trace anomaly vanishes if the massless scalar field is conformally coupled to gravity. Conformal coupling also ensures a finite Casimir energy and finite values of the pressure upon parallel plates.

We consider the issue of statistics for identical particles or fields in $\kappa$-deformed spaces, where the system admits a symmetry group $G$. We obtain the twisted flip operator compatible with the action of the symmetry group, which is relevant for describing particle statistics in the presence of the noncommutativity. It is shown that for a special class of realizations, the twisted flip operator is independent of the ordering prescription.

We propose an electric-magnetic duality and conjecture an exact conformal window for a class of nonsupersymmetric $U(N_c)$ gauge theories with fermions in the (anti)symmetric representation of the gauge group and $N_f$ additional scalar and fermion flavors. The duality exchanges $N_c\to N_f-N_c\mp 4$ leaving $N_f$ invariant, and has common features with Seiberg duality in $\mathcal{N}=1$ super QCD (SQCD) with $SU$ or $SO/Sp$ gauge group. At large $N$ the duality holds due to planar equivalence with $\mathcal{N}=1$ SQCD. At finite $N$ we embed these gauge theories in a setup with D-branes and orientifolds in a nonsupersymmetric, but tachyon-free, noncritical type 0B string theory and argue in favor of the duality in terms of boundary and crosscap state monodromies as in analogous supersymmetric situations. One can verify explicitly that the resulting duals have matching global anomalies. Finally, we comment on the moduli space of these gauge theories and discuss other potential nonsupersymmetric examples that could exhibit similar dualities.

If a homogeneous plane lightlike shell collides head on with a homogeneous plane electromagnetic shock wave having a step-function profile then no backscattered gravitational waves are produced. We demonstrate, by explicit calculation, that if the matter is accompanied by a homogeneous plane electromagnetic shock wave with a step-function profile then backscattered gravitational waves appear after the collision.

In this article it is shown that the thermodynamical evolution of a Schwarzschild de Sitter space is the evaporation of its black hole. The result is extended in higher dimensions to Lovelock theories of gravity with a single positive cosmological constant.

In the context of constrained quantum mechanics, reference systems are used to construct relational observables that are invariant under the action of the symmetry group. Upon measurement of a relational observable, the reference system undergoes an unavoidable measurement “back-action” that modifies its properties. In a quantum-gravitational setting, it has been argued that such a back-action may produce effects that are described at an effective level as a form of deformed (or doubly) special relativity. We examine this possibility using a simple constrained system that has been extensively studied in the context of quantum information. While our conclusions support the idea of a symmetry deformation, they also reveal a host of other effects that may be relevant to the context of quantum gravity, and could potentially conceal the symmetry deformation.

We introduce analytic solutions for a class of two components bouncing models, where the bounce is triggered by a negative energy density perfect fluid. The equation of state of the two components are constant in time, but otherwise unrelated. By numerically integrating regular equations for scalar cosmological perturbations, we find that the (would-be) growing mode of the Newtonian potential before the bounce never matches with the growing mode in the expanding stage. For the particular case of a negative energy density component with a stiff equation of state we give a detailed analytic study, which is in complete agreement with the numerical results. We also perform analytic and numerical calculations for long wavelength tensor perturbations, obtaining that, in most cases of interest, the tensor spectral index is independent of the negative energy fluid and given by the spectral index of the growing mode in the contracting stage. We compare our results with previous investigations in the literature.

We are presenting an internal linear combination CMB map, in which the foreground is reduced through harmonic variance minimization. We have derived our method by converting a general form of pixel-space approach into spherical harmonic space, maintaining full correspondence. By working in spherical harmonic space, spatial variability of linear weights is incorporated in a self-contained manner and our linear weights are continuous functions of position over the entire sky. The full correspondence to pixel-space approach enables straightforward physical interpretation on our approach. In variance minimization of a linear combination map, the existence of a cross term between residual foregrounds and CMB makes the linear combination of minimum variance differ from that of minimum foreground. We have developed an iterative foreground reduction method, where perturbative correction is made for the cross term. Our CMB map derived from the WMAP data is in better agreement with the WMAP best-fit $\Lambda \mathrm{CDM}$ model than the WMAP team’s internal linear combination map. We find that our method’s capacity to clean foreground is limited by the availability of enough spherical harmonic coefficients of good signal-to-noise ratio.

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the order of the perturbations to the Newtonian gravitational potential, hence necessarily small on cosmological scales. Moreover, comparable fluctuations are associated with different gauge choices. We also demonstrate that the often used homogeneous approximation is unrealistic, and that the so-called dark energy mutation is a trivial artifact of an effective, single fluid description. Finally, we discuss the particular case where the dark energy fluid is nonminimally coupled to dark matter.

We propose a solution to the $\mu /B_{\mu }$ problem in gauge mediation. The novel feature of our solution is that it uses dynamics of the hidden sector, which is often present in models with dynamical supersymmetry breaking. We give an explicit example model of gauge mediation where a very simple messenger sector generates both $\mu$ and $B_{\mu }$ at one loop. The usual problem, that $B_{\mu }$ is then too large, is solved by strong renormalization effects from the hidden sector which suppress $B_{\mu }$ relative to $\mu$. Our mechanism relies on an assumption about the signs of certain incalculable anomalous dimensions in the hidden sector. Making these assumptions not only allows us to solve the $\mu /B_{\mu }$ problem but also leads to a characteristic superpartner spectrum which would be a smoking gun signal for our mechanism.

We construct a new order parameter for finite temperature QCD by considering the quark condensate for U(1)-valued temporal boundary conditions for the fermions. Fourier transformation with respect to the boundary condition defines the dual condensate. This quantity corresponds to an equivalence class of Polyakov loops, thereby being an order parameter for the center symmetry. We explore the duality relation between the quark condensate and these dressed Polyakov loops numerically, using quenched lattice QCD configurations below and above the QCD phase transition. It is demonstrated that the Dirac spectrum responds differently to changing the boundary condition, in a manner that reproduces the expected Polyakov loop pattern. We find the dressed Polyakov loops to be dominated by the lowest Dirac modes, in contrast to thin Polyakov loops investigated earlier.

We report a study of semileptonic $B$ decays to $P$-wave $D^{**}$ mesons. Semileptonic decay to a $D_2^{*}$ meson is observed for the first time and its product branching ratio is measured to be $\mathcal{B}(B^{+}\to {\overline{D}}_2^{*0}{\ell }^{+}\nu )\times \mathcal{B}({\overline{D}}_2^{*0}\to D^{-}{\pi }^{+})=0.22\pm 0.03(\mathrm{stat}.)\pm 0.04(\mathrm{syst}.)\%$. The result is obtained using fully reconstructed $B$ tags from a data sample that contains $657\times {10}^{6}B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider.

The global supersymmetry is spontaneously broken if and only if the ground-state energy is strictly positive. We propose to use this fact to observe the spontaneous supersymmetry breaking in Euclidean lattice simulations. For lattice formulations that possess a manifest fermionic symmetry, there exists a natural choice of a Hamiltonian operator that is consistent with a topological property of the Witten index. We confirm validity of our idea in models of the supersymmetric quantum mechanics. We then examine a possibility of a dynamical supersymmetry breaking in the two-dimensional $\mathcal{N}=(2,2)$ super Yang-Mills theory with the gauge group $\mathrm{SU}(2)$, for which the Witten index is unknown. Differently from a recent conjectural claim, our numerical result tempts us to conclude that supersymmetry is not spontaneously broken in this system.

We present the results of a search for the production of an excited state of the electron, $e^{*}$, in proton-antiproton collisions at $\sqrt{s}=1.96\mathrm{TeV}$. The data were collected with the D0 experiment at the Fermilab Tevatron Collider and correspond to an integrated luminosity of approximately $1{\mathrm{fb}}^{-1}$. We search for $e^{*}$ in the process $p\overline{p}\to e^{*}e$, with the $e^{*}$ subsequently decaying to an electron plus photon. No excess above the standard model background is observed. Interpreting our data in the context of a model that describes $e^{*}$ production by four-fermion contact interactions and $e^{*}$ decay via electroweak processes, we set 95% C.L. upper limits on the production cross section ranging from 8.9 to 27 fb, depending on the mass of the excited electron. Choosing the scale for contact interactions to be $\Lambda =1\mathrm{TeV}$, excited electron masses below 756 GeV are excluded at the 95% C.L.