We show that the dynamic universality class of the QCD critical point is that of model H and discuss the dynamic critical exponents. We show that the baryon diffusion rate vanishes at the critical point. The dynamic critical index $z$ is close to 3.

The data on the total cross section ${\sigma }_{\mathrm{t}\mathrm{o}\mathrm{t}}({\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\mathrm{e}}^{+}{\mathrm{e}}^{-}b\overline{b})$ measured at LEP2 represent a serious challenge for perturbative QCD. In order to understand the origin of the excess of data over QCD calculations, we investigate the dependence of the four contributions to this cross section on $\gamma \gamma$ collision energy. As the reliability of the existing calculations of ${\sigma }_{\mathrm{t}\mathrm{o}\mathrm{t}}({\mathrm{e}}^{+}{\mathrm{e}}^{-}\to {\mathrm{e}}^{+}{\mathrm{e}}^{-}b\overline{b})$ depends, among other things, on the stability of the calculations of the cross section ${\sigma }_{\mathrm{t}\mathrm{o}\mathrm{t}}(\gamma \gamma \to b\overline{b})$ with respect to variations of the renormalization and factorization scales, we investigate this aspect in detail. We show that in most of the region relevant for the LEP2 data the existing QCD calculations of the cross section ${\sigma }_{\mathrm{t}\mathrm{o}\mathrm{t}}(\gamma \gamma \to b\overline{b})$ do not exhibit a region of local stability. A possible source of this instability is suggested.

This paper was published online on 26 August 2004 with a typographical error in Ref. [26]. The author of the second paper of Ref. [26] should be P. Mészáros. The name has been corrected as of 27 August 2004. The reference is correct in the printed version of the journal.

We present a general approach to construct a class of generalized topological field theories with constraints by means of generalized differential calculus and its application to connection theory. It turns out that not only the ordinary BF formulations of general relativity and Yang-Mills theories, but also the $N=1,2\mathrm{}$ chiral supergravities can be reformulated as these constrained generalized topological field theories once the free parameters in the Lagrangian are specially chosen. We also show that the Chern-Simons action on the boundary may naturally be induced from the generalized topological action in the bulk, rather than introduced by hand.

Two relations, the virial relation $M_{\mathrm{ADM}}{=M}_{\mathrm{K}}$ and the first law in the form $\delta M_{\mathrm{ADM}}=\Omega \delta J,$ should be satisfied by a solution and a sequence of solutions describing binary compact objects in quasiequilibrium circular orbits. Here, $M_{\mathrm{ADM}},$ $M_{\mathrm{K}},$ J, and $\Omega$ are the Arnowitt-Deser-Misner (ADM) mass, Komar mass, angular momentum, and orbital angular velocity, respectively. $\delta$ denotes an Eulerian variation. These two conditions restrict the allowed formulations that we may adopt. First, we derive relations between $M_{\mathrm{ADM}}$ and $M_{\mathrm{K}}$ and between $\delta M_{\mathrm{ADM}}$ and $\Omega \delta J$ for general asymptotically flat spacetimes. Then, to obtain solutions that satisfy the virial relation and sequences of solutions that satisfy the first law at least approximately, we propose a formulation for computation of quasiequilibrium binary neutron stars in general relativity. In contrast to previous approaches in which a part of the Einstein equation is solved, in the new formulation, the full Einstein equation is solved with maximal slicing and in a transverse gauge for the conformal three-metric. Helical symmetry is imposed in the near zone, while in the distant zone, a waveless condition is assumed. We expect the solutions obtained in this formulation to be excellent quasiequilibria as well as initial data for numerical simulations of binary neutron star mergers.

It has been suggested that a scalar field with negative kinetic energy, or “ghost,” could be the source of the observed late-time cosmological acceleration. Naively, such theories should be ruled out by the catastrophic quantum instability of the vacuum. We derive phenomenological bounds on the Lorentz-violating ultraviolet cutoff $\Lambda$ which must apply to low-energy effective theories of ghosts, in order to keep the instability at unobservable levels. Assuming only that ghosts interact at least gravitationally, we show that $\Lambda \lesssim 3\mathrm{MeV}$ for consistency with the cosmic gamma ray background. We also show that theories of ghosts with a Lorentz-conserving cutoff are completely excluded.

We consider a brane world and its gravitational linear perturbations. We present a general solution of the perturbations in the bulk and find the complete perturbed junction conditions for generic brane dynamics. We also prove that (spin 2) gravitational waves in the great majority of cases can arise only in connection with a non-vanishing anisotropic stress. This has far reaching consequences for inflation in the brane world. Moreover, contrary to the case of the radion, the perturbations are stable.

It is shown that nonadiabatic cosmological perturbations cannot appear during the period of reheating following inflation with a single scalar inflaton field.

We perform an update of our previous analysis of the constraints on possible deviations of $\mathrm{Hb}\overline{b}$ coupling parametrized as ${(m}_b/v\left)\right(a+i{\gamma }_{5}b),$ arising from a scalar-pseudoscalar mixing, where the process $e^{+}{e}^{-}\to b\overline{b}\nu \overline{\nu }$ was used. In this paper we include a complete simulation of the process $e^{+}{e}^{-}\to b\overline{b}{e}^{+}{e}^{-}$ and combine these results to obtain tighter bounds on the deviations of the parameters a and b from their standard model values that could be measured at the Next Linear Collider.

The product-group unification is a model of unified theories, in which the masslessness of the two Higgs doublets and the absence of dimension-5 proton decay are guaranteed by a symmetry. It is based on the $\mathrm{SU}\left(5\right)\times \mathrm{U}\mathrm{}\left(N\right)\mathrm{}(N=2,3\mathrm{})\mathrm{}$ gauge group. It is known that various features of the model are explained naturally when it is embedded in a brane world. An idea of how to accommodate all the particles of the model in the type-IIB brane world is described. The GUT-breaking sector is realized by a D3–D7 system, and chiral quarks and leptons arise from the intersection off D7-branes. The D-brane configuration can be a geometric realization of the nonparallel family structure of quarks and leptons, an idea proposed to explain the large mixing angles observed in neutrino oscillations. The trilinear interaction of the next-to-minimal supersymmetric standard model is obtained naturally in some cases.

The rare decay $\overrightarrow{B}\phi K_S$ is a well-known probe of physics beyond the standard model because it arises only through loop effects yet has the same time-dependent CP asymmetry as $\overrightarrow{B}\psi K_S.$ Motivated by recent data suggesting new physics in $\overrightarrow{B}\phi K_S,$ we look to supersymmetry for possible explanations, including contributions mediated by gluino loops and by Higgs bosons. Chirality-preserving LL and RR gluino contributions are generically small, unless gluinos and squarks masses are close to the current lower bounds. Higgs contributions are also too small to explain a large asymmetry if we impose the current upper limit on ${B(B}_s\to {\mu }^{+}{\mu }^{-}).\mathrm{}$ On the other hand, chirality-flipping LR and RL gluino contributions can provide sizable effects and while remaining consistent with related results in $\overrightarrow{B}\psi K_S,$ $\Delta M_s,$ $\overrightarrow{B}{X}_s\gamma$ and other processes. We discuss how the LR and RL insertions can be distinguished using other observables, and we provide a string-based model and other estimates to show that the needed sizes of mass insertions are reasonable.

We investigate the possibility of observing CP asymmetries in partial widths for the decays $B^{-}\to {\pi }^{+}{\pi }^{-}{K}^{-}$ and $B^{-}\to K^{+}{K}^{-}{K}^{-}$ produced by the interference of the nonresonant decay amplitude with resonant amplitudes. The resonant states that subsequently decay into ${\pi }^{+}{\pi }^{-}$ and $K^{+}{K}^{-}$ or $K^{-}{\pi }^{+}$ are charmonium $\overline{c}c$ states with $J^P{=0\mathrm{}}^{+}{,1\mathrm{}}^{-}{,1\mathrm{}}^{+}$ or the $\phi \mathrm{}\left(1020\right)\mathrm{}$ meson. We find that the largest partial width asymmetry comes from the ${\chi }_{c0\mathrm{}}$ resonance, while the resonance $\psi \mathrm{}\left(2S\right)\mathrm{}$ gives a partial width asymmetry of the order 10%.

Based on $\overline{B}\to D^{\left(*\right)}{K}^{-}{K}^{*0}$ decay data, which supports factorization, we propose to extract the kaon axial form factor in the factorization framework. Experiment indicates that the $K^{-}{K}^{*0}$ pair is produced by an axial current where only one out of three axial form factors is dominant. The axial form factor can be extracted by fitting the $K^{-}{K}^{*0}$ mass spectrum with an $a_1\mathrm{}\left(1260\right)\mathrm{}$-resonance plus QCD-motivated nonresonant contributions, which can be improved as data improves.

We analyze the recently proposed spectral quark model in the light of chiral perturbation theory in curved space-time. In particular, we calculate the chiral coefficients $L_1,\dots {,L}_{10},$ as well as the coefficients $L_{11},$ $L_{12},$ and $L_{13},$ appearing when the model is coupled to gravity. The analysis is carried for the SU(3) case. We analyze the pattern of chiral symmetry breaking as well as elaborate on the satisfaction of anomalies. Matching the model results to resonance meson exchange yields the relation between the masses of the scalar, tensor, and vector mesons, $M_{f_0}{=M}_{f_2}=\sqrt{2}{M}_V=4\mathrm{}\sqrt{{3/N}_c}\pi f_{\pi }.$ Finally, the large-$N_c$ limit suggests the dual relations in the vector and scalar channels, $M_V{=M}_S=2\mathrm{}\sqrt{{6/N}_c}\pi f_{\pi }$ and $〈r^2{〉}_S^{1/2}=〈r^2{〉}_V^{1/2}=1\mathrm{}\sqrt{N_c}/2\mathrm{}\pi f_{\pi }=0.59\mathrm{}\mathrm{fm}.$

Recently several experiments have reported evidence for pentaquark ${\Theta }^{+}.$ H1 experiment at HERA-B has also reported evidence for ${\Theta }_c.$ ${\Theta }^{+}$ is interpreted as a bound state of an $\overline{s}$ with four other light quarks udud which is a member of the antidecuplet of flavor ${\mathrm{SU}\left(3\right)\mathrm{}}_f,$ while ${\Theta }_c$ is a heavy state obtained with the $\overline{s}$ in ${\Theta }^{+}$ being replaced by a $\overline{c}$ which is a member of an antisixtet. A heavy pentaquark triplet can also be formed with a $\overline{c}$ and four light quarks. Similarly heavy pentaquark antisixtet and triplet can be formed with the $\overline{c}$ being replaced by a $\overline{b}.$ We study decay processes involving at least one heavy pentaquark using ${\mathrm{SU}\left(3\right)\mathrm{}}_f$ and estimate the decay widths for some decay modes. We find several relations for heavy pentaquark decays into another heavy pentaquark and a ${B(B}^{*})$ or a ${D(D}^{*})$ which can be tested in the future. The B can also decay through weak interaction to charmed heavy pentaquarks. We also study some B decay modes with a heavy pentaquark in the final states. Experiments at B factories will provide important information about the heavy pentaquark properties.

We present measurements of the branching fractions and charge asymmetries (where appropriate) of two-body B decays to ${\eta }^{(\prime )}{K}^{*},$ ${\eta }^{(\prime )}\rho ,$ ${\eta }^{(\prime )}{\pi }^0,$ $\omega {\pi }^0,$ and $\phi {\pi }^0.$ The data were recorded with the BABAR detector at PEP-II and correspond to $89\times {10}^6$ $B\overline{B}$ pairs produced in $e^{+}{e}^{-}$ annihilation through the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ resonance. We find significant signals for two decay modes and measure the branching fractions $\mathcal{B}{(B}^{+}\to \eta K^{*+})=(25.6\mathrm{}\pm 4.0\pm 2.4)\times {10}^{-6}$ and $\mathcal{B}{(B}^0\to \eta K^{*0})=(18.6\mathrm{}\pm 2.3\pm 1.2)\times {10}^{-6},$ where the first error is statistical and the second systematic. We also find evidence with significance 3.5σ for a third decay mode and measure $\mathcal{B}{(B}^{+}\to \eta {\rho }^{+})=(9.2\mathrm{}\pm 3.4\pm 1.0)\times {10}^{-6}.$ For other channels, we set 90% C.L. upper limits of $\mathcal{B}{(B}^0\to \eta {\rho }^0)<\mathrm{}1.5\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^{+}\to {\eta }^{\prime }{K}^{*+})<\mathrm{}14\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^0\to {\eta }^{\prime }{K}^{*0})<\mathrm{}7.6\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^{+}\to {\eta }^{\prime }{\rho }^{+})<\mathrm{}22\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^0\to {\eta }^{\prime }{\rho }^0)<\mathrm{}4.3\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^0\to \eta {\pi }^0)<\mathrm{}2.5\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^0\to {\eta }^{\prime }{\pi }^0)<\mathrm{}3.7\mathrm{}\times {10}^{-6},$ $\mathcal{B}{(B}^0\to \omega {\pi }^0)<\mathrm{}1.2\mathrm{}\times {10}^{-6},$ and $\mathcal{B}{(B}^0\to \phi {\pi }^0)<\mathrm{}1.0\mathrm{}\times {10}^{-6}.$ For self-flavor-tagging modes with significant signals, the time-integrated charge asymmetries are ${\mathcal{A}}_{\mathrm{ch}}\left(\eta K^{*+}\right)=+0.13\mathrm{}\pm 0.14\pm 0.02$ and ${\mathcal{A}}_{\mathrm{ch}}\left(\eta K^{*0}\right)=+0.02\mathrm{}\pm 0.11\pm \mathrm{0.02.}$

We study the realization of dimensional reduction and the validity of the hard thermal loop expansion for $\lambda {\phi }^4$ theory at finite temperature, using an environmentally friendly finite-temperature renormalization group with a fiducial temperature as flow parameter. The one-loop renormalization group allows for a consistent description of the system at low and high temperatures, and, in particular, of the phase transition. The main results are that dimensional reduction applies, apart from a range of temperatures around the phase transition, at high temperatures (compared to the zero temperature mass) only for sufficiently small coupling constants, while the hard thermal loop expansion is valid below (and rather far from) the phase transition, and, again, at high temperatures only in the case of sufficiently small coupling constants. We emphasize that close to the critical temperature, physics is completely dominated by thermal fluctuations that are not resummed in the hard thermal loop approach and where universal quantities are independent of the parameters of the fundamental four-dimensional theory.

The renormalization of operators responsible for soft supersymmetry breaking is usually calculated by starting at some high scale and including only visible sector interactions in the evolution equations, while ignoring hidden sector interactions. Here we explain why this is correct only for the most trivial structures in the hidden sector and discuss possible implications. This investigation was prompted by the idea of conformal sequestering. In that framework hidden sector renormalizations by nearly conformal dynamics are critical. In the original models of conformal sequestering it was necessary to impose hidden sector flavor symmetries to achieve the sequestered form. We present models that can evade this requirement and lead to no-scale or anomaly mediated boundary conditions, but the necessary structures do not seem generic. More generally, the ratios of scalar masses to gaugino masses, the $\mu$ term, the $B\mu$ term, A terms, and the gravitino mass can be significantly affected.

Quantum fluctuations of a certain class of bulk operators defined in spatial subvolumes of Minkowski space-time have an unexpected area scaling property. We present evidence that such area scaling may be ascribed to a boundary theory. We first highlight the implications of area scaling with two examples in which the boundary area of the spatial regions is not monotonic with their volume. Next, we show that the covariance of two operators that are restricted to two different regions in Minkowski space scale linearly with their mutual boundary area. Finally, we present an example which demonstrates why this implies an underlying boundary theory.

In this paper we show that a universe dominated by two components, namely, domain walls and dissipative dark matter, such that the former slowly decays into the latter, may drive power-law cosmological acceleration consistent with the high redshift supernovae data, while the ratio between the energy densities of both components remains fixed at late times thus solving the coincidence problem of present acceleration. Likewise, we estimate the aforesaid ratio at early times.