Quantum corrections to the Schwarzschild metric generated by loop diagrams have been considered by Bjerrum-Bohr, Donoghue, and Holstein (BHD) [Phys. Rev. D 68, 084005 (2003)], and Khriplovich and Kirilin (KK) [J. Exp. Theor. Phys. 98, 1063 (2004)]. Though the same field variables in a covariant gauge are used, the results obtained differ from one another. The reason is that the different sets of diagrams have been used. Here we will argue that the quantum corrections to metric must be independent of the choice of field variables, i.e. must be reparametrization invariant. Using simple reparametrization transformation, we will show that the contribution considered by BDH, is not invariant under it. Meanwhile the corrections to the Schwarzschild metric considered by KK satisfies the requirement of the invariance.

The Goldberger-Wise mechanism of stabilizing modulus in the Randall-Sundrum braneworld, by introducing a bulk scalar field with quartic interaction terms localized at the 3-branes, has been extremely popular as a stabilizing mechanism when the backreaction of the scalar field on the geometry is negligibly small. In this paper we reexamine the mechanism by an exact analysis without resorting to the approximations adopted by Goldberger and Wise. An exact calculation of the stabilization condition indicates the existence of closely spaced minimum and a maximum for the potential and also brings out some new features involved in the context of the stabilization of such braneworld models.

Stationary, axisymmetric, and asymptotically flat spacetimes of dust of which trajectories are integral curves of the time translation Killing vector are investigated. The flow has no Newtonian limit. Asymptotic flatness implies the existence of singularities of the curvature scalar that are distributions and that are not isolated from regularity regions of the flow. The singularities are closely related to the presence of additional stresses that contribute negative active mass to the total (Komar) mass, which is zero for asymptotically flat spacetimes. Several families of solutions were constructed.

I examine some nonanthropic approaches to the string landscape. These approaches are based on finding the initial conditions of the universe using the wave function of the multiverse to select the most probable vacuum out of this landscape. All approaches tackled so far seem to have their own problems and there is no clear-cut alternative to anthropic reasoning. I suggest that finding the initial conditions may be irrelevant since all possible vacua on the landscape are possible initial state conditions and eternal inflation could generate all the other vacua. We are now left to reason out why we are observing the small value of the cosmological constant. I address this issue in the context of noncritical string theory in which all values of the cosmological constant on the landscape are departures from the critical equilibrium state.

In this note we straightforwardly derive and make use of the quantum $R$ matrix for the $\mathfrak{s}\mathfrak{u}(2|2)$ super Yang-Mills spin chain in the manifest $\mathfrak{s}\mathfrak{u}(1|2)$-invariant formulation, which solves the standard quantum Yang-Baxter equation, in order to obtain the correspondent (undressed) classical $r$ matrix from the first order expansion in the “deformation” parameter $2\pi /\sqrt{\lambda }$ and check that this last solves the standard classical Yang-Baxter equation. We analyze its bialgebra structure, its dependence on the spectral parameters, and its pole structure. We notice that it still preserves an $\mathfrak{s}\mathfrak{u}(1|2)$ subalgebra, thereby admitting an expression in terms of a combination of projectors, which spans only a subspace of $\mathfrak{s}\mathfrak{u}(1|2)\otimes \mathfrak{s}\mathfrak{u}(1|2)$. We study the residue at its simple pole at the origin and comment on the applicability of the classical Belavin-Drinfeld type of analysis.

The confinement problem has been solved in the anisotropic $(2+1)$-dimensional $\mathrm{SU}(N)$ Yang-Mills theory at weak coupling. In this paper, we find the low-lying spectrum for $N=2$. The lightest excitations are pairs of fundamental particles of the $(1+1)$-dimensional $\mathrm{SU}(2)\times \mathrm{SU}(2)$ principal chiral sigma model bound in a linear potential, with a specified matching condition where the particles overlap. This matching condition can be determined from the exactly-known $S$-matrix for the sigma model.

We describe how a survey of the polarization of the cosmic microwave background induced by Compton scattering in galaxy clusters can be used to make a full spatial reconstruction of the primordial ($z\sim 1089$) matter distribution inside our surface of last scattering. This “polarization tomography” can yield a spatial map of the initial state of the Universe just as gravitational collapse was beginning to drive structure formation. We present a transparent method and simple formulas from which one can compute the 3D primordial map in real and in Fourier space, given a 3D map of the polarization due to galaxy clusters. The advantage of the real space reconstruction is that it is free from the statistical uncertainties which are inherent in the Fourier space reconstruction. We discuss how noise, partial sky covering and depth of the survey can affect the results.

We provide a consistency relation between cosmological observables in general relativity without relying on the equation of state of dark energy. The consistency relation should be satisfied if general relativity is the correct theory of gravity and dark energy clustering is negligible. As an extension, we also provide the DGP counterpart of the relation.

Using a generalized procedure for obtaining the equation of motion of a propagating fermionic particle, we examine previous claims for a lightlike preferred axis embedded in the framework of Lorentz-invariance violation with preserved algebra. In a high energy scale, the corresponding equation of motion is reduced to a conserving lepton number chiral (very special relativity) equation, and in a low energy scale, the Dirac equation for a free particle is recovered. The new dynamics introduces some novel ingredients (modified cross section) to the phenomenology of the tritium beta-decay end point.

Events with one lepton, one photon, and missing energy are the subject of recent searches at the Fermilab Tevatron. We compute possible contributions to these types of events from the process $p\overline{p}\to \gamma l{\nu }_l{\nu }_{\tau }{\overline{\nu }}_{\tau }$, where $l=e$, $\mu$ in the context of a low scale technicolor model. We find that with somewhat tighter cuts than the ones used in the CDF search, it could be possible to either confirm or exclude this model in a small region of its parameter space.

We present a simple scheme for constructing models that achieve successful gauge mediation of supersymmetry breaking. In addition to our previous work [H. Murayama and Y. Nomura, Phys. Rev. Lett. 98, 151803 (2007)] that proposed drastically simplified models using metastable vacua of supersymmetry breaking in vectorlike theories, we show there are many other successful models using various types of supersymmetry-breaking mechanisms that rely on enhanced low-energy $U(1{)}_R$ symmetries. In models where supersymmetry is broken by elementary singlets, one needs to assume $U(1{)}_R$ violating effects are accidentally small, while in models where composite fields break supersymmetry, emergence of approximate low-energy $U(1{)}_R$ symmetries can be understood simply on dimensional grounds. Even though the scheme still requires somewhat small parameters to sufficiently suppress gravity mediation, we discuss their possible origins due to dimensional transmutation. The scheme accommodates a wide range of the gravitino mass to avoid cosmological problems.

One way to ameliorate the SUSY flavor and $CP$ problems is to postulate that scalar masses lie in the TeV or beyond regime. For example, the focus point (FP) region of the minimal supergravity (mSUGRA) model is especially compelling in that heavy scalar masses can coexist with low fine-tuning while yielding the required relic abundance of cold dark matter (via a mixed Higgsino-bino neutralino). We examine many of the characteristics of collider events expected to arise at the CERN LHC in models with multi-TeV scalars, taking the mSUGRA FP region as a case study. The collider events are characterized by a hard component arising from gluino pair production, plus a soft component arising from direct chargino and neutralino production. Gluino decays in the FP region are characterized by lengthy cascades yielding very large jet and lepton multiplicities, and a large $b$-jet multiplicity. Thus, as one steps to higher jet, $b$-jet or lepton multiplicity, signal-over-background rates should steadily improve. The lengthy cascade decays make mass reconstruction via kinematic edges difficult; however, since the hard component is nearly pure gluino pair production, the gluino mass can be extracted to $\pm 8\%$ via total rate for $E_T^{\mathrm{miss}}+\ge 7\mathrm{\text{−}}\mathrm{\text{jet}}+\ge 2b\mathrm{\text{−}}\mathrm{\text{jet}}$ events, assuming $100{\mathrm{fb}}^{-1}$ of integrated luminosity. The distribution of invariant mass of opposite-sign/same-flavor dileptons in the hard component exhibits two dilepton mass edges: $m_{{\tilde{Z}}_2}-m_{{\tilde{Z}}_1}$ and $m_{{\tilde{Z}}_3}-m_{{\tilde{Z}}_1}$. As a consistency check, the same mass edges should be seen in isolated opposite-sign dileptons occurring in the soft component trilepton signal which originates mainly from chargino-neutralino production.

We present results for the spectrum of static-light mesons from $N_f=2$ lattice QCD. These results were obtained using all-to-all light-quark propagators on an anisotropic lattice, yielding an improved signal resolution when compared to more conventional lattice techniques. With a light-quark mass close to the strange quark, we have measured the splittings between the ground-state $S$-wave static-light meson and higher excitations. We attempt to identify the quantum numbers of the excited states in the context of the reduced spatial symmetries of the lattice.

The nucleon form factors of the energy-momentum tensor are studied in the large-$N_c$ limit in the framework of the chiral quark-soliton model.

We explore a novel possibility of determining the solar model parameters, which serve as input in the calculations of the solar neutrino fluxes, by exploiting the data from direct measurements of the fluxes. More specifically, we use the rather precise value of the ${}^8\mathrm{B}$ neutrino flux, ${\varphi }_B$ obtained from the global analysis of the solar neutrino and KamLAND data, to derive constraints on each of the solar model parameters on which ${\varphi }_B$ depends. We also use more precise values of ${}^7\mathrm{Be}$ and $pp$ fluxes as can be obtained from future prospective data and discuss whether such measurements can help in reducing the uncertainties of one or more input parameters of the standard solar model.

We present a search for electroweak production of single top quarks in the $s$-channel ($p\overline{p}\to t\overline{b}+X$) and $t$-channel ($p\overline{p}\to tq\overline{b}+X$) modes. We have analyzed $230{\mathrm{pb}}^{-1}$ of data collected with the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy of $\sqrt{s}=1.96\mathrm{TeV}$. No evidence for a single top quark signal is found. We set 95% confidence level upper limits on the production cross sections, based on binned likelihoods formed from a neural network output. The observed (expected) limits are 6.4 pb (4.5 pb) in the $s$-channel and 5.0 pb (5.8 pb) in the $t$-channel.

We show by examples that multichannel mixing can affect both the parameters extracted from neutrino oscillation experiments, and more general conclusions derived by fitting the experimental data under the assumption that only two channels are involved in the mixing. Implications for MiniBooNE are noted and an example based on maximal $CP$ violation displays profound implications for the two data sets (${\nu }_{\mu }$ and ${\overline{\nu }}_{\mu }$) of that experiment.

A recently proposed phenomenological model, which includes nonperturbative effects from dimension two gluon condensates, is applied to analyze the available lattice data for the heavy quark free energy in the deconfined phase of quenched QCD. For large $q\overline{q}$ separations, we recover previous results for the Polyakov loop, exhibiting unequivocal power corrections in the temperature. For the $q\overline{q}$ potential at finite temperature and finite separation, we find that a good overall description of the lattice data can be achieved once the condensate is properly accounted for. In addition, the model predicts a duality between the zero temperature potential as a function of the $q\overline{q}$ separation, on the one hand, and the quark self-energy as a function of the temperature, on the other, which turns out to be satisfied to a high degree by the lattice data.

A search for optical line emission from the two-photon decay of relic axions was conducted in the galaxy clusters Abell 2667 and 2390, using spectra from the VIMOS (Visible MultiObject Spectrograph) integral field unit at the Very Large Telescope. New upper limits to the two-photon coupling of the axion are derived, and are at least a factor of 3 more stringent than previous upper limits in this mass window. The improvement follows from a larger collecting area, integration time, and spatial resolution, as well as from improvements in signal to noise and sky subtraction made possible by strong-lensing mass models of these clusters. The new limits either require that the two-photon coupling of the axion be extremely weak or that the axion mass window between 4.5 eV and 7.7 eV be closed. Implications for sterile-neutrino dark matter are discussed briefly also.