Based on the recent proposal of $\mathcal{N}=8$ superconformal gauge theories of the multiple M2 branes, we derive ($2+1$)-dimensional supersymmetric Janus field theories with a space-time dependent coupling constant. From the original Bagger-Lambert model, we get a supersymmetric field theory with a similar action to the $N$ D2 branes, but the coupling varies with the space-time as a function of the light-cone coordinate, $g(t+x)$. Half of the supersymmetries can be preserved. We further investigate the M2 brane action deformed by mass and Myers-like terms. In this case, the final Yang-Mills action is deformed by mass and Myers terms, and the coupling behaves as $\exp (\mu x)$ where $\mu$ is a constant mass parameter. Weak coupling gauge theory is continuously changed to strong coupling in the large $x$ region.

We present exact solutions describing rotating, inhomogeneous dust with generic initial data in $2+1$ dimensional anti-de Sitter space-time and show how they are smoothly matched to the Banados-Teitelboim-Zanelli (BTZ) solution in the exterior. The metrics, which are the rotational analogues of the $2+1$ dimensional LeMaitre-Tolman-Bondi family, are described by their angular momentum and one additional constant which, together with the angular momentum, determines the energy density of the dust cloud. The weak energy condition gives a constraint on the angular momentum profile inside the cloud. Solutions can be stationary or time dependent, but only the time-dependent solutions can be matched consistently to a BTZ exterior. No singularity is formed in either the stationary or the time-dependent cases.

We investigate the spacetime of a slowly rotating black hole in the Chern-Simons modified gravity. The long range feature of frame-dragging effect under the Chern-Simon gravity well explains the flat rotation curves of galaxies which is a central evidence of dark matter. Our solution provides a different scenario of rotating space from Gödel’s solution.

We look at the possibility of nonperturbative particle production after inflation from supersymmetry flat directions produced by rotating eigenstates thereby avoiding the standard adiabaticity conditions. This might lead to preheating and prevent the delay of thermalization of the Universe. We investigate the flat directions $LL{E}^c$ and $U^c{D}^c{D}^c$ and find no particle production. These two directions are very important, since they have been named as possible candidates for being the inflaton. We investigate $QLQLQL{E}^c$ and find particle production and therefore the possibility of preheating. We investigate the $LL{E}^c$ and $U^c{D}^c{D}^c$ directions appearing simultaneously, and find no production. Finally, we investigate $LL{E}^c$ and $QL{D}^c$ simultaneously—with one $L$-field in common. Here we do find particle production and therefore the possibility of preheating. This means that if supersymmetry flat directions are to delay thermalization and thus explain the (lack of) gravitino production, it is necessary to explain why complicated directions as $QLQLQL{E}^c$ are not exited, and why combinations like $LL{E}^c$ and $QL{D}^c$ are not both exited.

We discuss the flavor conversion of neutrinos from core-collapse supernovae that have oxygen-neon-magnesium (ONeMg) cores. Using the numerically calculated evolution of the star up to 650 ms post bounce, we find that, for the normal mass hierarchy, the electron neutrino flux in a detector shows signatures of two typical features of an ONeMg-core supernova: a sharp step in the density profile at the base of the He shell and a faster shock wave propagation compared to iron core supernovae. Before the shock hits the density step ($t\lesssim 150\mathrm{ms}$), the survival probability of electron neutrinos above $\sim 20\mathrm{MeV}$ of energy is about $\sim 0.68$, in contrast to values of $\sim 0.32$ or less for an iron core supernova. The passage of the shock through the step and its subsequent propagation cause a decrease of the survival probability and a decrease of the amplitude of oscillations in the Earth, reflecting the transition to a more adiabatic propagation inside the star. These changes affect the lower energy neutrinos first; they are faster and more sizable for larger ${\theta }_{13}$. They are unique of ONeMg-core supernovae, and give the possibility to test the speed of the shock wave. The time modulation of the Earth effect and its negative sign at the neutronization peak are the most robust signatures in a detector.

We present a measurement of $D^0\mathrm{\text{−}}{\overline{D}}^0$ mixing parameters using the ratios of lifetimes extracted from a sample of $D^0$ mesons produced through the process $D^{*+}\to D^0{\pi }^{+}$, which decay to $K^{-}{\pi }^{+}$, $K^{-}{K}^{+}$, or ${\pi }^{-}{\pi }^{+}$. The lifetimes of the $CP$-even, Cabibbo-suppressed modes $K^{-}{K}^{+}$ and ${\pi }^{-}{\pi }^{+}$ are compared with that of the $CP$-mixed, Cabibbo-favored mode $K^{-}{\pi }^{+}$ to obtain a measurement of $y_{CP}$, which in the limit of $CP$ conservation corresponds to the mixing parameter $y$. The analysis is based on a data sample of $384{\mathrm{fb}}^{-1}$ collected by the BABAR detector at the PEP-II asymmetric-energy $e^{+}{e}^{-}$ collider. We obtain $y_{CP}=[1.24\pm 0.39(\mathrm{stat})\pm 0.13(\mathrm{syst})]\%$, which is evidence for $D^0\mathrm{\text{−}}{\overline{D}}^0$ mixing at the $3\sigma$ level, and $\Delta Y=[-0.26\pm 0.36(\mathrm{stat})\pm 0.08(\mathrm{syst})]\%$, where $\Delta Y$ constrains possible $CP$ violation. Combining this result with a previous BABAR measurement of $y_{CP}$ obtained from a separate sample of $D^0\to K^{-}{K}^{+}$ events, we obtain $y_{CP}=[1.03\pm 0.33(\mathrm{stat})\pm 0.19(\mathrm{syst})]\%$.

We reply to the recent criticism by Garriga and Tanaka of our proposal that quantum gravitational loop corrections may lead to a secular screening of the effective cosmological constant. Their argument rests upon a renormalization scheme in which the composite operator $(R\sqrt{-g}-4\Lambda \sqrt{-g}{)}_{\mathrm{ren}}$ is defined to be the trace of the renormalized field equations. Although this is a peculiar prescription, we show that it does not preclude secular screening. Moreover, we show that a constant Ricci scalar does not even classically imply a constant expansion rate. Other important points are: (1) the quantity $R_{\mathrm{ren}}$ of Garriga and Tanaka is neither a properly defined composite operator, nor is it constant; (2) gauge dependence does not render a Green’s function devoid of physical content; (3) scalar models on a nondynamical de Sitter background (for which there is no gauge issue) can induce arbitrarily large secular contributions to the stress tensor; (4) the same secular corrections appear in observable quantities in quantum gravity; and (5) the prospects seem good for deriving a simple stochastic formulation of quantum gravity in which the leading secular effects can be summed and for which the expectation values of even complicated, gauge invariant operators can be computed at leading order.

In the context of the recent interest in solvable models of scattering mediated by non-Hermitian Hamiltonians (cf. H. F. Jones, Phys. Rev. D 76, 125003 (2007)) we show that the well-known variability of the ad hoc choice of the metric $\Theta$ which defines the physical Hilbert space of states can help us to clarify several apparent paradoxes. We argue that with a suitable $\Theta$, a fully plausible physical picture of the scattering can be recovered. Quantitatively, our new recipe is illustrated on an exactly solvable toy model.

We consider possible resolutions of singularities in a contracting anisotropic universe for a class of higher derivative gravity theories. We give evidence that for our models the big crunch singularity may be replaced by a nearly flat Minkowski-like phase before the Universe reenters an anisotropic expansion in a time-symmetric manner.

The complete set of analytic solutions of the geodesic equation in a Schwarzschild-(anti-)de Sitter space-time is presented. The solutions are derived from the Jacobi inversion problem restricted to the set of zeros of the theta function, called the theta divisor. In its final form the solutions can be expressed in terms of derivatives of Kleinian sigma functions. The different types of the resulting orbits are characterized in terms of the conserved energy and angular momentum as well as the cosmological constant. Using the analytical solution, the question whether the cosmological constant could be a cause of the Pioneer anomaly is addressed. The periastron shift and its post-Schwarzschild limit is derived. The developed method can also be applied to the geodesic equation in higher dimensional Schwarzschild space-times.

We reexamine the process of loop quantization for flat isotropic models in cosmology. In particular, we contrast different inequivalent “loop quantizations” of these simple models through their respective successes and limitations and assess whether they can lead to any viable physical description. We propose three simple requirements which any such admissible quantum model should satisfy: (i) independence from any auxiliary structure, such as a fiducial interval/cell introduced to define the phase space when integrating over noncompact manifolds; (ii) existence of a well defined classical limit, and (iii) a sensible “Planck scale” where quantum gravitational effects become manifest. We show that even when it may seem that one can have several possible loop quantizations, these physical requirements considerably narrow down the consistent choices. Apart from the so-called improved dynamics of loop quantum cosmology, none of the other available inequivalent loop quantizations pass the above tests, showing the limitations of lattice refinement models to approximate the homogeneous sector and loop modified quantum geometrodynamics. We conclude that amongst a large class of loop quantizations in isotropic cosmology, there is a unique consistent choice.

The problem of measuring gravitomagnetic effects by means of lunar laser ranging (LLR) is investigated. The relevant terms in the Einstein-Infeld-Hoffmann equations of motion in barycentric coordinates are parametrized by a parameter ${\eta }_G$, which is fitted along with other parameters to LLR data and not derived from postfit residuals as it was done by other authors. The physical relevance of ${\eta }_G$ and its relation to the preferred frame parameter ${\alpha }_1$ are discussed. Finally, ${\alpha }_1$ is fitted to LLR data by choosing the Barycentric Celestial Reference System as preferred frame instead of the cosmic rest frame determined via the temperature anisotropy of the cosmic microwave background radiation.

Large-scale structures originate from coherent motions induced by inhomogeneities in the primeval gravitational potential. Here, we investigate the two-point statistics of the second derivative of the potential, the tidal shear, under the assumption of Gaussianity. We derive an exact closed form expression for the angular averaged, two-point distribution of the shear components which is valid for an arbitrary Lagrangian separation. This result is used to write down the two-point statistics of the shear eigenvalues in compact form. Next, we examine the large-scale asymptotics of the correlation of the shear eigenvalues and the alignment of the principal axes. The analytic results are in good agreement with measurements obtained from random realizations of the gravitational potential. Finally, we show that a number of two-point distributions of the shear eigenvalues are well approximated by Gaussian bivariates over a wide range of separation and smoothing scales. We speculate that the Gaussian approximation also holds for multiple point distributions of the shear eigenvalues. It is hoped that these results will be relevant for studies aimed at describing the properties of the (evolved) matter distribution in terms of the statistics of the primordial shear field.

We test the robustness and flexibility of the Chevallier-Polarski-Linder (CPL) parametrization of the dark energy equation of state $w(z)=w_0+w_a\frac{z}{1+z}$ in recovering a four-parameter steplike fiducial model. We constrain the parameter space region of the underlying fiducial model where the CPL parametrization offers a reliable reconstruction. It turns out that non-negligible biases leak into the results for recent ($z<2.5$) rapid transitions, but that CPL yields a good reconstruction in all other cases. The presented analysis is performed with supernova Ia data as forecasted for a space mission like SNAP/JDEM, combined with future expectations for the cosmic microwave background shift parameter $R$ and the baryonic acoustic oscillation parameter $A$.

We investigate coupled quintessence cosmologies with a matter consisting of particles with an increasing mass. While negligible in early cosmology, the appearance of a growing matter component has stopped the evolution of the cosmon field at a redshift around six. In turn, this has triggered the accelerated expansion of the Universe. We propose to associate growing matter with neutrinos. Then the presently observed dark energy density and its equation of state are determined by the neutrino mass.

In supersymmetric models the lightest Higgs boson may decay with a sizable branching ratio into a pair of light neutralinos. We analyze such decays within the context of the minimal supersymmetric standard model with $R$-parity violation, where the neutralino itself is unstable and decays into standard model fermions. We show that the $R$-parity violating couplings induce novel Higgs decay signals that might facilitate the discovery of the Higgs boson at colliders. At the LHC, the Higgs may be observed, for instance, through its decay—via two neutralinos—into final states containing missing energy and isolated charged leptons such as ${\ell }^{\pm }{\ell }^{\mp }$, ${\ell }^{\pm }{\ell }^{\pm }$, $3\ell$, and $4\ell$. Another promising possibility is the search for the displaced vertices associated with the neutralino decay. We also point out that Higgs searches at the LHC might additionally provide the first evidence of $R$-parity violation.

We present results on the mass of the nucleon and the $\Delta$ using two dynamical degenerate twisted mass quarks and the tree-level Symanzik improved gauge action. The evaluation is performed at four quark masses corresponding to a pion mass in the range of about 300–600 MeV on lattices of 2.1–2.7 fm at three lattice spacings less than 0.1 fm. We check for cutoff effects by evaluating these baryon masses on lattices of spatial size 2.1 fm at $\beta =3.9$ and $\beta =4.05$ and on a lattice of 2.4 fm at $\beta =3.8$. The values we find are compatible within our statistical errors. Lattice results are extrapolated to the physical limit using continuum chiral perturbation theory. Performing a combined fit to our lattice data at $\beta =3.9$ and $\beta =4.05$ we find a nucleon mass of $963\pm 12(\mathrm{stat})\pm 8(\mathrm{syst})\mathrm{MeV}$ where we used the lattice spacings determined from the pion decay constant to convert to physical units. The systematic error due to the chiral extrapolation is estimated by comparing results obtained at $\mathcal{O}(p^3)$ and $\mathcal{O}(p^4)$ heavy baryon chiral perturbation theory. The nucleon mass at the physical point provides an independent determination of the lattice spacing. Using heavy baryon chiral perturbation theory at $\mathcal{O}(p^3)$ we find $a_{\beta =3.9}=0.0889\pm 0.0012(\mathrm{stat})\pm 0.0014(\mathrm{syst})\mathrm{fm}$, and $a_{\beta =4.05}=0.0691\pm 0.0010(\mathrm{stat})\pm 0.0010(\mathrm{syst})\mathrm{fm}$, in good agreement with the values determined from the pion decay constant. Using results from our two smaller lattices spacings at constant $r_0{m}_{\pi }$ we estimate the continuum limit and check consistency with results from the coarser lattice. Results at the continuum limit are chirally extrapolated to the physical point. Isospin violating lattice artifacts in the $\Delta$-system are found to be compatible with zero for the values of the lattice spacings used in this work. Performing a combined fit to our lattice data at $\beta =3.9$ and $\beta =4.05$ we find for the masses of the ${\Delta }^{++,-}$ and ${\Delta }^{+,0}$ $1315\pm 24(\mathrm{stat})\mathrm{MeV}$ and $1329\pm 30(\mathrm{stat})\mathrm{MeV}$, respectively. We confirm that in the continuum limit they are also degenerate.

A number of proposals have been put forward to account for the observed accelerating expansion of the Universe through modifications of gravity. One specific scenario, Dvali-Gabadadze-Porrati (DGP) gravity, gives rise to a potentially observable anomaly in the solar system: all planets would exhibit a common anomalous precession, $d\omega /dt$, in excess of the prediction of general relativity. We have used the Planetary Ephemeris Program (PEP) along with planetary radar and radio tracking data to set a constraint of $|d\omega /dt{|}_{\mathrm{obs}}<0.02$ arcseconds per century on the presence of any such common precession. This sensitivity falls short of that needed to detect the estimated universal precession of $|d\omega /dt{|}_{\mathrm{DGP}}=5\times {10}^{-4}$ arcseconds per century expected in the DGP scenario. We discuss the fact that ranging data between objects that orbit in a common plane cannot constrain the DGP scenario. It is only through the relative inclinations of the planetary orbital planes that solar system ranging data have sensitivity to the DGP-like effect of universal precession. In addition, we illustrate the importance of performing a numerical evaluation of the sensitivity of the data set and model to any perturbative precession.

In a framework that makes close contact with modern effective field theories for nonrelativistic bound states at zero temperature, we study the real-time evolution of a static quark-antiquark pair in a medium of gluons and light quarks at finite temperature. For temperatures ranging from values larger to smaller than the inverse distance of the quark and antiquark, $1/r$, and at short distances, we derive the potential between the two static sources, and calculate their energy and thermal decay width. Two mechanisms contribute to the thermal decay width: the imaginary part of the gluon self-energy induced by the Landau damping phenomenon, and the quark-antiquark color-singlet to color-octet thermal breakup. Parametrically, the first mechanism dominates for temperatures such that the Debye mass is larger than the binding energy, while the latter, which we quantify here for the first time, dominates for temperatures such that the Debye mass is smaller than the binding energy. If the Debye mass is of the same order as $1/r$, our results are in agreement with a recent calculation of the static Wilson loop at finite temperature. For temperatures smaller than $1/r$, we find new contributions to the potential, both real and imaginary, which may be relevant to understand the onset of heavy quarkonium dissociation in a thermal medium.

We study resonant leptogenesis at the electroweak phase transition in the singlet Majoron model with right-handed neutrinos. We consider a scenario where the SM gauge group and the lepton number break down spontaneously during a second-order electroweak phase transition. We calculate the flavor- and temperature-dependent leptonic asymmetries, by including the novel contributions from the transverse polarizations of the $W^{\pm }$ and $Z$ bosons. The required resummation of the gauge-dependent, off-shell, heavy-neutrino self-energies is consistently treated within the gauge-invariant framework of the pinch technique. Taking into consideration the freeze-out dynamics of sphalerons, we delineate the parameter space of the model that is compatible with successful electroweak resonant leptogenesis. The phenomenological and astrophysical implications of the model are discussed.