The spherically symmetric dust model of Lemaître and Tolman can describe wormholes, but the causal communication between the two asymptotic regions through the neck is even less than in the vacuum (Schwarzschild-Kruskal-Szekeres) case. We investigate the anisotropic generalization of the wormhole topology in the Szekeres model. The function $E(r,p,q)\mathrm{}$ describes the deviation from spherical symmetry if ${\partial }_{r}E\ne 0,$ but this requires the mass to be increasing with radius, ${\partial }_{r}M>\mathrm{}0,$ i.e. nonzero density. We investigate the geometrical relations between the mass dipole and the loci of the apparent horizon and shell crossings. We present the various conditions that ensure physically reasonable quasispherical models, including a regular origin, regular maxima and minima in the spatial sections, and the absence of shell crossings. We show that physically reasonable values of ${\partial }_{r}E\ne 0$ cannot compensate for the effects of ${\partial }_{r}M>\mathrm{}0\mathrm{}$ in any direction, so that communication through the neck is still worse than in the vacuum. We also show that a handle topology cannot be created by identifying hypersufaces in the two asymptotic regions on either side of a wormhole, unless a surface layer is allowed at the junction. This impossibility includes the Schwarzschild-Kruskal-Szekeres case.

A transfer matrix for gauge theories on a lattice with Kogut-Susskind fermions in the flavor basis is constructed and some difficulties in the spin-diagonal basis are pointed out.

The responses of quark condensates to the chemical potential, as a function of temperature T and chemical potential $\mu ,$ are calculated within the Nambu–Jona-Lasinio (NJL) model. We compare our results with those from the recent lattice QCD simulations [QCD-TARO Collaboration, S. Choe et al., Nucl. Phys. B (Proc. Suppl.) 106, 462 (2002)]. The NJL model and lattice calculations show qualitatively similar behavior, and they will be complimentary ways to study hadrons at finite density. The behavior above $T_c$ requires more elaborated analyses.

We study instantons in QCD with many colors. We first discuss a number of qualitative arguments concerning the large $N_c$ scaling behavior of a random instanton ensemble. We show that most hadronic observables are compatible with standard large $N_c$ counting rules provided the average instanton size is $O\left(1\right)\mathrm{}$ and the instanton density is ${O(N}_c)$ in the large $N_c$ limit. This is not the case for the topological susceptibility and the mass of the ${\eta }^{\prime }.$ For these observables consistency with conventional large $N_c$ counting requires that fluctuations in the instanton liquid are suppressed compared to Poissonian fluctuations. Using mean field estimates and numerical simulations we show that the required scaling behavior of the instanton density is natural in models in which the instanton density is regularized in terms of a classical repulsive core. We also show that in these models fluctuations of the topological charge are suppressed and that $m_{{\eta }^{\prime }}^2{=O(1/N}_c).\mathrm{}$ We conclude that the instanton liquid model is not necessarily in conflict with the ${1/N}_c$ expansion.

We study the off-diagonal Goldberger-Treiman relation (ODGTR) and its discrepancy (ODGTD) in the N, $\Delta ,$ $\pi$ sector through $\mathcal{O}{(p}^2)$ using heavy baryon chiral perturbation theory. To this order, the ODGTD and axial vector N to $\Delta$ transition radius are determined solely by low-energy constants. Loop corrections appear at $\mathcal{O}{(p}^4).\mathrm{}$ For low-energy constants of natural size, the ODGTD would represent a $\sim 2\%$ correction to the ODGTR. We discuss the implications of the ODGTR and ODGTD for lattice and quark model calculations of the transition form factors and for parity-violating electroexcitation of the $\Delta .$

We present the fully differential production and decay of a $W^{\prime }$ boson, with arbitrary vector and axial-vector couplings, to any final state at next-to-leading order in QCD. We demonstrate a complete factorization of couplings at next-to-leading order in both the partial width of the $W^{\prime }$ boson and in the full two-to-two cross section. We provide numerical predictions for the contribution of a $W^{\prime }$ boson to single-top-quark production, and separate results based on whether the mass of the right-handed neutrino ${\nu }_R$ is light enough for the leptonic decay channel to be open. The single-top-quark analysis will allow for an improved direct $W^{\prime }$ mass limit of 525–550 GeV using data from run I of the Fermilab Tevatron. We propose a modified tolerance method for estimating parton distribution function uncertainties in cross sections.

Semileptonic, $\overrightarrow{B}\pi l\overline{\nu },$ decays are studied on quenched anisotropic lattices using tree-level tadpole improved Symanzik glue, nonrelativistic QCD heavy quark and D234 light quark actions. Constrained fitting methods are applied to extract ground state contributions to two-point and three-point correlators. We agree with previous lattice determinations of the form factors. The major source of systematic error here, as in previous work, comes from the chiral extrapolation to the physical pion mass. Future calculations must work at lighter quark masses to resolve this.

We analyze and quantify how the color-flavor locked (CFL) phase in dense matter enhances the parameter space for absolute stability (strange matter). We find that the “CFL strange matter” phase can be the true ground state of hadronic matter for a much wider range of the parameters of the model (the gap of the QCD Cooper pairs $\Delta ,$ the strange quark mass $m_s,$ and the bag constant $B)$ than the state without any pairing, and derive a full equation of state and an accurate analytic approximation to the lowest order in $\Delta$ and $m_s$ which may be directly used for applications. The effects of pairing on the equation of state are found to be small (as previously expected), but not negligible, and may be relevant for astrophysics.

We present an improved measurement of the standard model CP violation parameter $\sin 2{\phi }_1$ (also known as $\sin 2\beta )$ based on a sample of $85\times {10}^6$ $B\overline{B}$ pairs collected at the ${\rm Y}\mathrm{}\left(4S\right)\mathrm{}$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. One neutral B meson is reconstructed in a $J/\psi K_S^0,$ $\psi {\mathrm{}\left(2S\right)K}_S^0,$ ${\chi }_{c1\mathrm{}}{K}_S^0,$ ${\eta }_c{K}_S^0,$ $J/\psi K^{*0},$ or $J/\psi K_L^0$ CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time interval between the two B meson decay points, we obtain $\sin 2{\phi }_1=0.719\mathrm{}\pm 0.074\left(\mathrm{stat}\right)\pm 0.035\left(\mathrm{syst}\right).\mathrm{}$

We construct an $\mathrm{SU}\left(6\right)/Sp\left(6\right)\mathrm{}$ non-linear sigma model in which the Higgs bosons arise as pseudo Goldstone bosons. There are two Higgs doublets whose masses have no one-loop quadratic sensitivity to the cutoff of the effective theory, which can be at around 10 TeV. The Higgs potential is generated by gauge and Yukawa interactions, and is distinctly different from that of the minimal supersymmetric standard model. At the TeV scale, the new bosonic degrees of freedom are a single neutral complex scalar and a second copy of $\mathrm{SU}\left(2\right)\mathrm{}\times U\left(1\right)\mathrm{}$ gauge bosons. Additional vector-like pairs of colored fermions are also present.

We employ an effective Lagrangian approach and use CERN LEP data to place severe bounds on universality violations of the couplings of ${\nu }_e,$ ${\nu }_{\mu },$ and ${\nu }_{\tau }$ to the Z boson. Our results justify the assumption of universality in these couplings that is usually made, such as, for example, in the analysis of solar neutrinos detected at SNO.

The $\overrightarrow{B}\pi l\nu$ weak decay form factors are calculated via light-cone sum rules within the framework of the heavy quark effective theory. We calculate the leading and the relevant subleading universal form factors. Our results are matched to the known soft pion limit. We also address the large pion energy limit of our sum rule results. Our results are compared with those of other approaches.

We extend the perturbative approach developed in an earlier work to deal with Lagrangians which have arbitrary higher order time derivative terms for both bosons and fermions. This approach enables us to find an effective Lagrangian with only first time derivatives order by order in the coupling constant. As in the pure bosonic case, to the first order, the quantized Hamiltonian is bounded from below whenever the potential is. We show in the example of a single complex fermion that higher derivative interactions result in an effective mass and change of vacuum for the low energy modes. The supersymmetric noncommutative Wess-Zumino model is considered as another example. We also comment on the higher derivative terms in Witten’s string field theory and the effectiveness of level truncation.

Local boundary conditions for spinor fields are expressed in terms of a 1-parameter family of boundary operators, and find applications ranging from (supersymmetric) quantum cosmology to the bag model in quantum chromodynamics. The present paper proves that, for massless spinor fields on the Euclidean ball in dimensions $d=2,4,6,$ the resulting $\zeta \mathrm{}\left(0\right)\mathrm{}$ value is independent of such a $\theta$ parameter, while the various heat-kernel coefficients exhibit a $\theta$ dependence which is eventually expressed in a simple way through hyperbolic functions and their integer powers.

We consider a quantum field theory that creates at any point of the space-time particles described by a q-deformed Heisenberg algebra which is interpreted as a phenomenological quantum theory describing the scattering of spin-0 composed particles. We discuss the generalization of Wick’s expansion for this case and we compute perturbatively the scattering $1+\overrightarrow{2}{1}^{\prime }{+2\mathrm{}}^{\prime }$ to second order in the coupling constant. The result we find shows that the structure of a composed particle, described here phenomenologically by the deformed algebraic structure, can modify in a simple but nontrivial way the perturbation expansion for the process under consideration.

Commutative Yang-Mills theories in $1+1$ dimensions exhibit an interesting interplay between geometrical properties and $U\left(N\right)\mathrm{}$ gauge structures: in the exact expression of a Wilson loop with n windings a nontrivial scaling intertwines n and N. In the noncommutative case the interplay becomes tighter owing to the merging of space-time and “internal” symmetries in a larger gauge group $U\left(\infty \right).\mathrm{}$ We perform an explicit perturbative calculation of such a loop up to $\mathcal{O}{(g}^6);$ rather surprisingly, we find that in the contribution from the crossed graphs (the genuine noncommutative terms) the scaling we mentioned occurs for large n and N in the limit of maximal noncommutativity $\theta =\infty .$ We present arguments in favor of the persistence of such a scaling at any perturbative order and succeed in summing the related perturbative series.

I generalize the inflationary flow equations of Hoffman and Turner to arbitrary order in slow roll. This makes it possible to study the predictions of slow roll inflation in the full observable parameter space of the tensor/scalar ratio r, spectral index n, and running $dn/d\ln k.\mathrm{}$ It also becomes possible to identify exact fixed points in the parameter flow. I numerically evaluate the flow equations to fifth order in slow roll for a set of randomly chosen initial conditions and find that the models cluster strongly in the observable parameter space, indicating a “generic” set of predictions for slow roll inflation. I comment briefly on the interesting proposed correspondence between flow in inflationary parameter space and renormalization group flow in a boundary conformal field theory.

We generalize a previously obtained result for the case of a few other static hyperbolic universes with manifolds of nontrivial topology as spatial sections.

Ultralight scalar fields provide an interesting alternative to WIMPS as halo dark matter. In this paper we consider the effect of embedding a supermassive black hole within such a halo, and estimate the absorption probability and the accretion rate of dark matter onto the black hole. We show that the accretion rate would be small over the lifetime of a typical halo, and hence that supermassive central black holes can coexist with scalar field halos.