We report a measurement of the CP-violation parameter $\sin 2\beta$ with $B^0\to J/\psi K_S^0$ decays in which the $J/\psi$ decays to hadrons or to muons that do not satisfy our standard identification criteria. With a sample of 88 million $B\overline{B}$ events collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, we reconstruct $100\pm 17$ such events, with $J/\overrightarrow{\psi }{\pi }^{+}{\pi }^{-}{\pi }^0$ being the most prevalent, and measure $\sin 2\beta =1.56\mathrm{}\pm 0.42\left(\mathrm{stat}\right)\pm 0.21\left(\mathrm{syst}\right).\mathrm{}$

A generally covariant extension of general relativity (GR) in which a dynamical unit timelike vector field is coupled to the metric is studied in the asymptotic weak field limit of spherically symmetric static solutions. The two post-Newtonian parameters known as the Eddington-Robertson-Schiff parameters are found to be identical to those in the case of pure GR, except for some nongeneric values of the coefficients in the Lagrangian.

CP asymmetry in $\overrightarrow{B}\phi K_S$ decay is studied in the special context of supersymmetry theories, in which the charginos play an important role. We find that in addition to the gluino, the chargino can also make large contributions to CP asymmetry in $\overrightarrow{B}\phi K_S$ decay. After considering the constraints from $\overrightarrow{B}J/\psi K_S$ decay, we study three special scenarios: (a) large mixing between left-handed charm and top squarks, (b) large mixing between right-handed charm and top squarks, (c) large mixing between both left-handed charm-top squarks and right-handed charm-top squarks. We show quantitatively that because of large squark mixing within the second and third generations, an $O\left(1\right)\mathrm{}$ effect on CP violation in $\overrightarrow{B}\phi K_S$ is possible.

We study big-crunch–big-bang cosmologies that correspond to exact world-sheet superconformal field theories of type II strings. The string theory spacetime contains a big crunch and a big bang cosmology, as well as additional “whisker” asymptotic and intermediate regions. Within the context of free string theory, we compute, unambiguously, the scalar fluctuation spectrum in all regions of spacetime. Generically, the big crunch fluctuation spectrum is altered while passing through the bounce singularity. The change in the spectrum is characterized by a function $\Delta ,$ which is momentum and time dependent. We compute $\Delta$ explicitly and demonstrate that it arises from the whisker regions. The whiskers are also shown to lead to “entanglement” entropy in the big bang region. Finally, in the Milne orbifold limit of our superconformal vacua, we show that $\overrightarrow{\Delta }1$ and, hence, the fluctuation spectrum is unaltered by the big-crunch–big-bang singularity. We comment on, but do not attempt to resolve, subtleties related to gravitational back reaction and light winding modes when interactions are taken into account.

We address the renormalized effective action for a Randall-Sundrum brane running in 5D bulk space. The running behavior of the brane action is obtained by shifting the brane position without changing the background and fluctuations. After an appropriate renormalization, we obtain an effective, low energy brane world action, in which the effective 4D Planck mass is independent of the running position. We address some implications for this effective action.

We demonstrate the attractor behavior of inflation driven by a scalar or tachyon field in the context of the recently proposed four-dimensional effective gravity induced on the world-volume of a three-brane in five-dimensional Einstein gravity, and we obtain a set of exact inflationary solutions. The phase portraits indicate that an initial kinetic term decays rapidly and does not prevent the onset of inflation. The trajectories more rapidly reach the slow rolling curve in the braneworld scenario than in the standard cosmology.

We describe new solutions of Yang-Mills-Higgs theories consisting of magnetic monopoles in a phase with fully broken gauge symmetry. Rather than spreading out radially, the magnetic field lines form flux tubes. The solution is topologically stable and, when embedded in $\mathcal{N}=2\mathrm{}$ SQCD, preserves 1/4 of the supercharges. From the perspective of the flux tube the monopole appears as a kink. Many monopoles may be threaded onto a single flux tube and placed at arbitrary separation to create a stable, BPS necklace of solitons.

A renormalization-group procedure for effective particles is applied to quantum chromodynamics of one flavor of quarks with a large mass m in order to calculate light-front Hamiltonians for heavy quarkonia $H_{\lambda }$ using perturbative expansion in the coupling constant ${\alpha }_{\lambda }.$ $\lambda$ is the renormalization-group parameter with the interpretation of an inverse of the spatial size of the color charge distribution in the effective quarks and gluons. The eigenvalue equation for $H_{\lambda }$ couples quark-antiquark states with sectors of a larger number of constituents. The coupling to states with more than one effective gluon, and interactions in the quark-antiquark-gluon sector, are removed at the price of introducing an ansatz for the gluon mass ${\mu }^2.$ The simplified equation is used to evaluate a new Hamiltonian of order ${\alpha }_{\lambda }$ that acts only in the effective quark-antiquark sector and in the nonrelativistic limit turns out to contain the Coulomb term with Breit-Fermi corrections and a spin-independent harmonic oscillator term with a frequency $\omega =\left[\mathrm{}\right(4/3\left)\right({\alpha }_{\lambda }/\pi \left){]}^{1/2}\lambda \right(\lambda {/m)}^2(\pi {/1152)}^{1/4}.$ The latter originates from the hole excavated in the overlapping quark self-interaction gluon clouds by the exchange of effective gluons between the quarks. The new term is largely independent of the details of ${\mu }^2$ and in principle can fit into the ballpark of phenomenology. The first approximation can be improved by including more terms in $H_{\lambda }$ and solving the eigenvalue equations numerically.

It is known that the imposition of orbifold boundary conditions on a background scalar field can give rise to a nontrivial vacuum expectation value along extra dimensions, which in turn generates fat branes and associated unconventional Kaluza-Klein (KK) towers of fermions. We study the structure of these KK towers in the limit of one large extra dimension and show that normalizable (bound) states of massless and massive fermions can exist at both orbifold fixed points. A closer look, however, indicates that orbifold boundary conditions act to suppress at least half of the bound KK modes, while periodic boundary conditions tend to drive high-lying modes to a conventional structure. By investigating the scattering of fermions on branes, we analytically compute the masses and wave functions of KK spectra in the presence of these boundary conditions up to the one-loop level. The implication of KK-number nonconservation couplings for the Coulomb potential is also examined.

We study the conditions for spontaneous symmetry breaking of the $\mathrm{}(2+1)\mathrm{}$-dimensional noncommutative ${\phi }^6$ model in the small-θ limit. In this regime, considering the model as a cutoff theory, it is reasonable to assume translational invariance as a property of the vacuum state and study the conditions for spontaneous symmetry breaking by an effective potential analysis. An investigation of up to the two-loop level reveals that noncommutative effects can modify drastically the shape of the effective potential. Under reasonable conditions, the nonplanar sector of the theory can become dominant and induce symmetry breaking for values of the mass and coupling constants not reached by the commutative counterpart.

We calculate the antiproton flux due to relic neutralino annihilations, in a two-dimensional diffusion model compatible with stable and radioactive cosmic ray nuclei. We find that the uncertainty in the primary flux induced by the propagation parameters alone is about two orders of magnitude at low energies, and it is mainly determined by the lack of knowledge of the thickness of the diffusive halo. On the contrary, different dark matter density profiles do not significantly alter the flux: a Novarro-Frenk-White distribution produces fluxes which are at most 20% higher than an isothermal sphere. The most conservative choice for propagation parameters and dark matter distribution normalization, together with current data on cosmic antiprotons, cannot lead to any definitive constraint on the supersymmetric parameter space, either in a low-energy effective minimal supersymmetric standard model, or in a minimal supergravity scheme. However, if the best choice for propagation parameters—corresponding to a diffusive halo of $L=4\mathrm{}\mathrm{kpc}$—is adopted, some supersymmetric configurations with the neutralino mass $m_{\chi }\lesssim 100\mathrm{GeV}$ should be considered as excluded. An enhancement flux factor—due for instance to a clumpy dark halo or a higher local dark matter density—would imply a more severe cut on the supersymmetric parameters.

We discuss the matching of the BPS part of the spectrum for a (super)membrane, which gives the possibility of getting the membrane’s results via string calculations. In the small coupling limit of M theory the entropy of the system coincides with the standard entropy of type IIB string theory (including the logarithmic correction term). The thermodynamic behavior at a large coupling constant is computed by considering M theory on a manifold with a topology $T^2\times R^9.$ We argue that the finite temperature partition functions (brane Laurent series for $p\ne 1)$ associated with the BPS p-brane spectrum can be analytically continued to well-defined functionals. It means that a finite temperature can be introduced in brane theory, which behaves like finite temperature field theory. In the limit $\overrightarrow{p}0$ (point particle limit) it gives rise to the standard behavior of thermodynamic quantities.

Equatorial motion of test particles in Kerr–de Sitter spacetimes is considered. Circular orbits are determined, their properties are discussed for both black-hole and naked-singularity spacetimes, and their relevance for thin accretion disks is established. The circular orbits constitute two families that coalesce at the so-called static radius. The orientation of the motion along the circular orbits is, in accordance with case of asymptotically flat Kerr spacetimes, defined by relating the motion to the locally nonrotating frames. The minus-family orbits are all counterrotating, while the plus-family orbits are usually corotating relative to these frames. However, the plus-family orbits become counterrotating in the vicinity of the static radius in all Kerr–de Sitter spacetimes, and they become counterrotating in the vicinity of the ring singularity in Kerr–de Sitter naked-singularity spacetimes with a low enough rotational parameter. In such spacetimes, the efficiency of the conversion of the rest energy into heat energy in the geometrically thin plus-family accretion disks can reach extremely high values exceeding the efficiency of the annihilation process. The transformation of a Kerr–de Sitter naked singularity into an extreme black hole due to accretion in the thin disks is briefly discussed for both the plus-family and minus-family disks. It is shown that such a conversion leads to an abrupt instability of the innermost parts of the plus-family accretion disks that can have strong observational consequences.

We study excited baryon decay widths in large $N_c$ QCD. It was suggested previously that some spin-flavor mixed-symmetric baryon states have strong couplings of ${O(N}_c^{-1/2})$ to nucleons [implying narrow widths of ${O(1/N}_c\left)\right],$ as opposed to the generic expectation based on Witten’s counting rules of an ${O(N}_c^0)$ coupling. The calculation obtaining these narrow widths was performed in the context of a simple quark-shell model. This paper addresses the question of whether the existence of such narrow states is a general property of large $N_c$ QCD. We show that a general large $N_c$ QCD analysis does not predict such narrow states; rather they are a consequence of the extreme simplicity of the quark model.

An interesting interplay between self-duality, the Kodama (Chern-Simons) state and knot invariants is shown to emerge in the quantum theory of an Abelian gauge theory. More precisely, when a self-dual representation of the CCR is chosen, the corresponding vacuum in the Schrödinger representation is precisely given by the Kodama state. Several consequences of this construction are explored.

When constructing numerical solutions to systems of evolution equations subject to a constraint, one must decide what role the constraint equations will play in the evolution system. In one popular choice, known as free evolution, a simulation is treated as a Cauchy problem, with the initial data constructed to satisfy the constraint equations. This initial data are then evolved via the evolution equations with no further enforcement of the constraint equations. The evolution, however, via the discretized evolution equations introduce constraint violating modes at the level of truncation error, and these constraint violating modes will behave in a formalism dependent way. This paper presents a generic method for incorporating the constraint equations into the evolution equations so that the off-constraint dynamics are biased toward the constraint satisfying solutions.

Recently, a number of intriguing results have been obtained for strongly coupled $\mathcal{N}=4\mathrm{}$ supersymmetric Yang-Mills theory in vacuum and matter, using the AdS-CFT correspondence. In this work, we provide a physical picture supporting and explaining most of these results within the gauge theory. The modified Coulomb’s law at strong coupling forces static charges to communicate via the high frequency modes of the gauge or scalar fields. Therefore, the interaction between even relativistically moving charges can be approximated by a potential. At strong coupling, WKB arguments yield a series of deeply bound states, whereby the large Coulomb attraction is balanced by centrifugation. The result is a constant density of light bound states at any value of the strong coupling, explaining why the thermodynamics and kinetics are coupling constant independent. In essence, at strong coupling the matter is not made of the original quasiparticles but of much lighter (binary) composites. A transition from weak to strong coupling is reminiscent of a transition from high to low temperature in QCD. We establish novel results for screening in vacuum and matter through a dominant set of diagrams some of which are in qualitative agreement with known strong coupling results.

We discuss inflationary cosmology in a five dimensional $\mathrm{SO}\left(10\right)\mathrm{}$ model compactified on $S^1{/(Z}_2\times Z_2^{\prime }),$ which yields ${\mathrm{SU}\left(3\right)\mathrm{}}_c\times {\mathrm{SU}\left(2\right)\mathrm{}}_L\times {U\left(1\right)\mathrm{}}_Y\times {U\left(1\right)\mathrm{}}_X$ below the compactification scale. The gauge symmetry $\mathrm{SU}\left(5\right)\mathrm{}\times {U\left(1\right)\mathrm{}}_X$ is preserved on one of the fixed points, while “flipped” ${\mathrm{SU}\left(5\right)\mathrm{}}^{\prime }\times {U\left(1\right)\mathrm{}}_X^{\prime }$ is on the other fixed point. Inflation is associated with ${U\left(1\right)\mathrm{}}_X$ breaking, and is implemented through F-term scalar potentials on the two fixed points. A brane-localized Einstein-Hilbert term allows both branes to have positive tensions during inflation. The scale of ${U\left(1\right)\mathrm{}}_X$ breaking is fixed from $\delta T/T$ measurements to be around ${10}^{16}\mathrm{GeV},$ and the scalar spectral index $n=0.98\mathrm{}–\mathrm{0.99.}$ The inflaton field decays into right-handed neutrinos whose subsequent out of equilibrium decay yields the observed baryon asymmetry via leptogenesis.

This paper is devoted to studying gauge embedding of either commutative and noncommutative theories in the framework of the symplectic formalism. We illustrate our ideas in the Proca model, the irrotational fluid model, and the noncommutative self-dual model. In the process of this new path of embedding, the infinitesimal gauge generators of the gauge embedded theory are easily and directly chosen. Among other advantages, this enables a greater control over the final Lagrangian and sheds some light on the so-called “arbitrariness problem.”

The arbitrariness in how the logarithm is defined within the QCD series for the inclusive electroproduction cross section is shown to affect the summation to all orders in ${\alpha }_s$ of leading and successively subleading logarithms within that perturbative series, even though such summations largely eliminate the residual dependence of the original series on the arbitrary renormalization scale $\mu .$ However, given that the original (unimproved) series is known to third order in ${\alpha }_s\left(\mu \right),$ this logarithm ambiguity is shown not to enter the optimally improved summation-of-logarithms series until the term which is fourth order in ${\alpha }_s\mathrm{}\left(s\right),$ where s is the physical center-of-mass energy squared. Consequently, the ambiguity in how the logarithm is defined is absorbable in the uncertainty associated with truncating the original perturbative series after its calculationally known terms.