We study the effect of internal space rotation on the gravitational properties of infinite straight and stationary cosmic strings. From the approximate solution of Einstein equations for the spinning $Q$-lump string, we obtain long-range gravitational acceleration resembling that of a rotating massive cylindrical shell. We also compute the angular velocity of the inertial frame dragging and the angle of light deflection by the $Q$-lump string. Matter accretion onto spinning strings can play a role in galaxy formation when the angular velocity times the string width is comparable to the speed of light.

We study the system of a self-dual Maxwell field coupled to 3D gravity with torsion, with the Maxwell field modified by a topological mass term. General structure of the field equations reveals a new, dynamical role of the classical central charges, and gives a simple correspondence between self-dual solutions with torsion and their Riemannian counterparts. We construct two exact self-dual solutions, corresponding to the sectors with a massless and massive Maxwell field, and calculate their conserved charges.

It is shown that in static and spherically symmetric configurations of the system of Maxwell field coupled to 3D gravity with torsion, at least one of the Maxwell field components has to vanish. Restricting our attention to the electric sector of the theory, we find an interesting exact solution, corresponding to the azimuthal electric field. Its geometric structure is to a large extent influenced by the values of two different central charges, associated to the asymptotic AdS structure of spacetime.

An energy for the homogeneous cosmological models is presented. More specifically, using an appropriate natural prescription, we find the energy within any region with any gravitational source for a large class of gravity theories—namely, those with a tetrad description—for all nine Bianchi types. Our energy is given by the value of the Hamiltonian with homogeneous boundary conditions; this value vanishes for all regions in all Bianchi class A models, and it does not vanish for any class B model. This is so not only for Einstein’s general relativity but, moreover, for the whole three-parameter class of tetrad-teleparallel theories. For the physically favored one-parameter subclass, which includes the teleparallel equivalent of Einstein’s theory as an important special case, the energy for all class B models is, contrary to expectation, negative.

Recently, the DAMA/LIBRA experiment has convincingly confirmed the DAMA/NaI annual modulation signal, experimentally demonstrating the existence of nonbaryonic dark matter in the halo of our galaxy. Meanwhile, in another part of town, other experiments such as CDMS and XENON10 have not detected any evidence for dark matter. One promising dark matter candidate which can reconcile the positive DAMA annual modulation signal with the null results from the other experiments is mirror dark matter. We reanalyze the mirror matter interpretation of the DAMA annual modulation signal utilizing (a) the new data from DAMA/LIBRA, including the measured energy dependence of the annual modulation signal, (b) an updated quenching factor which takes into account the channeling effect in $\mathrm{NaI}$ crystals, and (c) the latest constraints from CDMS/Ge, CDMS/Si and XENON10 experiments. We show that the simplest possibility of a ${\mathrm{He}}^{\prime }$ (and/or ${\mathrm{H}}^{\prime }$) dominated halo with a small ${\mathrm{O}}^{\prime }$ component is sufficient to fully explain all of the dark matter experiments. We also point out that a certain class of hidden sector dark matter models, although theoretically less appealing and less constrained, can mimic the success of the mirror dark matter model and hence are also viable.

We evaluate the ability of future data sets to discriminate among different quintessence dark energy models. This approach gives an alternative (and complementary) measure for assessing the impact of future experiments, as compared with the large body of literature that compares experiments in abstract parameter spaces (such as the well-known $w_0-w_a$ parameters) and more recent work that evaluates the constraining power of experiments on individual parameter spaces of specific quintessence models. We use the Dark Energy Task Force (DETF) models of future data sets and compare the discriminative power of experiments designated by the DETF as stages 2, 3, and 4 (denoting increasing capabilities). Our work reveals a minimal increase in discriminating power when comparing stage 3 to stage 2, but a very striking increase in discriminating power when going to stage 4 (including the possibility of completely eliminating some quintessence models). We also see evidence that even modest improvements over DETF stage 4 (which many believe are realistic) could result in even more dramatic discriminating power among quintessence dark energy models. We develop and demonstrate the technique of using the independently measured modes of the equation of state (derived from principle component analysis) as a common parameter space in which to compare the different quintessence models, and we argue that this technique is a powerful one. We use the PNGB, Exponential, Albrecht-Skordis, and Inverse Tracker (or inverse power law) quintessence models for this work. One of our main results is that the goal of discriminating among these models sets a concrete measure on the capabilities of future dark energy experiments. Experiments have to be somewhat better than DETF stage 4 simulated experiments to fully meet this goal.

We revisit inflation in induced gravity. Our focus is on models where the low scale Planck mass is completely determined by the breaking of the scaling symmetry in the field theory sector. The Higgs-like field which breaks the symmetry with a GUT-scale vacuum expectation value (vev) has nonminimal couplings to the curvature, induced by the gravitational couplings of the other light fields in the theory, so that its vev controls the gravitational strength. This field can drive inflation and give a low energy universe in very good agreement with the cosmological observations. The low energy dynamics of the standard model cannot be unitarized by the Higgsflaton, which decouples from the low energy theory, both because it picks up a large mass and because its direct couplings to the low energy modes are weakened. Instead, the short distance behavior of the standard model may be regulated by the dynamics of other light degrees of freedom, such as in Higgsless models.

In the last few years a number of works reported the appearance of thick branes with internal structure, induced by the parameter which controls the interaction between two scalar fields coupled to gravity in (4,1) dimensions in warped space-time with one extra dimension. Here we show that one can implement the control over the brane thickness without needing to change the potential parameter. On the contrary, this is going to be done by means of the variation of a parameter associated with the domain wall degeneracy. We also report the existence of novel and qualitatively different solutions for a critical value of the degeneracy parameter, which could be called critical Bloch branes.

Considering the gluon condensate corrections, the form factors relevant to the semileptonic rare $B_c\to D$, $D_s(J^P=0^{-})l^{+}{l}^{-}$ with $l=\tau$, $\mu$, $e$ and $B_c\to D$, $D_s(J^P=0^{-})\nu \overline{\nu }$ transitions are calculated in the framework of the three point QCD sum rules. The heavy quark effective theory limit of the form factors is computed. The branching fraction of these decays is also evaluated and compared with the predictions of the relativistic constituent quark model. Analyzing such transitions could give useful information about the strong interactions inside the pseudoscalar $D_s$ meson and its structure.

We study the Yukawa corrections to the $\gamma \gamma \to b\overline{b}$ cross section in the topcolor assisted technicolor models at the photon-photon colliders. We find that, for the favorable parameters, the relative corrections from pseudo-Goldstone bosons give out a $3.2\%\sim 5.9\%$ decrement of the cross section from the tree level when $\sqrt{s}=500\mathrm{GeV}$, the contributions from new extended technicolor gauge bosons $Z^{*}$ and colored gauge bosons $B$ are negligibly small, and the relative correction arising from new color-singlet heavy gauge boson $Z^{\prime }$ is less than $-3.2\%$. Therefore, the total relative corrections are significantly larger than the corresponding corrections in the standard model, the general two Higgs doublet model, and the minimal supersymmetric standard model. Since these corrections are obvious for the International Linear Colliders, the process $\gamma \gamma \to b\overline{b}$ is really interesting in testing the standard model and searching for the signs of technicolor.

We study the spectrum of the staggered Dirac operator in SU(2) gauge fields close to the free limit, for both the fundamental and the adjoint representation. Numerically we find a characteristic cluster structure with spacings of adjacent levels separating into three scales. We derive an analytical formula which explains the emergence of these different spectral scales. The behavior on the two coarser scales is determined by the lattice geometry and the Polyakov loops, respectively. Furthermore, we analyze the spectral statistics on all three scales, comparing to predictions from random matrix theory.

A next-to-leading order QCD calculation for single-inclusive jet photoproduction in unpolarized and longitudinally polarized lepton-hadron collisions is presented which consistently includes “direct” and “resolved” photon contributions. The computation is performed within the “small-cone approximation” in a largely analytical form. Phenomenological aspects of jet production at future $ep$ colliders such as the CERN Large Hadron electron Collider and the polarized Brookhaven National Laboratory eRHIC are discussed, placing particular emphasis on the perturbative stability of the predictions and the possibility to constrain the parton content of the photon.

Using the high energy color dipole approach, we study the exclusive photoproduction of lepton pairs $\gamma N\to {\gamma }^{*}(\to {\ell }^{+}{\ell }^{-})N$ (with $N=p$, $A$). We use simple models for the elementary dipole-hadron scattering amplitude that captures main features of the dependence on atomic number $A$, on energy and on momentum transfer $t$. This investigation is complementary to conventional partonic description of timelike Compton scattering, which considers quark handbag diagrams at leading order in ${\alpha }_s$ and simple models of the relevant generalized parton distributions. These calculations are input in electromagnetic interactions in $pp$ and $AA$ collisions to measured at the LHC.

We study two effective models for QCD, the Nambu-Jona-Lasinio -model and the linear sigma model extended by including a Polyakov loop potential, which is fitted to reproduce the pure gauge theory thermodynamics, and a coupling between the chiral fields and the Polyakov loop. Thus the resulting models have as relevant degrees of freedom the Polyakov loop and chiral fields. By comparing the extended models with the bare chiral models we can conclude that the addition of the Polyakov loop is necessary in order to obtain both qualitative and quantitative agreement with known results at finite temperatures. These results are extended to finite net-quark densities, several thermodynamical quantities are investigated in detail, and possible applications and consequences for relativistic heavy ion collision phenomenology are discussed.

We investigate the fluctuation effect of the di-fermion field in the crossover from Bardeen-Cooper-Schrieffer (BCS) pairing to a Bose-Einstein condensate (BEC) in a relativistic superfluid. We work within the boson-fermion model obeying a global U(1) symmetry. To go beyond the mean field approximation we use Cornwall-Jackiw-Tomboulis formalism to include higher-order contributions. The quantum fluctuations of the pairing condensate is provided by bosons in nonzero modes, whose interaction with fermions gives the two-particle-irreducible effective potential. It changes the crossover property in the BEC regime. With the fluctuations the superfluidity phase transition becomes the first order in a grand canonical ensemble. We calculate the condensate, the critical temperature $T_c$ and particle abundances as functions of a crossover parameter of the boson mass.

The TWIST Collaboration has performed new measurements of two of the parameters that describe muon decay: $\rho$, which governs the shape of the overall momentum spectrum, and $\delta$, which governs the momentum dependence of the parity-violating decay asymmetry. This analysis gives the results $\rho =0.75014\pm 0.00017(\mathrm{stat})\pm 0.00044(\mathrm{syst})\pm 0.00011(\eta )$, where the last uncertainty arises from the correlation between $\rho$ and the decay parameter $\eta$, and $\delta =0.75067\pm 0.00030(\mathrm{stat})\pm 0.00067(\mathrm{syst})$. These are consistent with the value of $3/4$ given for both parameters in the standard model of particle physics, and are a factor of two more precise than the measurements previously published by TWIST. A new global analysis of all available muon decay data incorporating these results is presented. Improved lower and upper limits on the decay parameter $P_{\mu }^{\pi }\xi$ of $0.99524<P_{\mu }^{\pi }\xi \le \xi <1.00091$ at 90% confidence are determined, where $P_{\mu }^{\pi }$ is the polarization of the muon when it is created during pion decay, and $\xi$ governs the muon decay asymmetry. These results set new model-independent constraints on the possible weak interactions of right-handed particles. Specific implications for left-right symmetric models are discussed.

Using a sample of $68.3\times {10}^6$ $K_L\to {\pi }^0{\pi }^0{\pi }^0$ decays collected in 1996–1999 by the KTeV (E832) experiment at Fermilab, we present a detailed study of the $K_L\to {\pi }^0{\pi }^0{\pi }^0$ Dalitz plot density. We report the first observation of interference from $K_L\to {\pi }^{+}{\pi }^{-}{\pi }^0$ decays in which ${\pi }^{+}{\pi }^{-}$ rescatters to ${\pi }^0{\pi }^0$ in a final-state interaction. This rescattering effect is described by the Cabibbo-Isidori model, and it depends on the difference in pion scattering lengths between the isospin $I=0$ and $I=2$ states, $a_0-a_2$. Using the Cabibbo-Isidori model, and fixing $(a_0-a_2)m_{{\pi }^{+}}=0.268\pm 0.017$ as measured by the CERN-NA48 collaboration, we present the first measurement of the $K_L\to {\pi }^0{\pi }^0{\pi }^0$ quadratic slope parameter that accounts for the rescattering effect: $h_{000}=(+0.59\pm {0.20}_{\mathrm{stat}}\pm {0.48}_{\mathrm{syst}}\pm {1.06}_{\mathrm{ext}})\times {10}^{-3}$, where the uncertainties are from data statistics, KTeV systematic errors, and external systematic errors. Fitting for both $h_{000}$ and $a_0-a_2$, we find $h_{000}=(-2.09\pm {0.62}_{\mathrm{stat}}\pm {0.72}_{\mathrm{syst}}\pm {0.28}_{\mathrm{ext}})\times {10}^{-3}$, and $m_{{\pi }^{+}}(a_0-a_2)=0.215\pm {0.014}_{\mathrm{stat}}\pm {0.025}_{\mathrm{syst}}\pm {0.006}_{\mathrm{ext}}$; our value for $a_0-a_2$ is consistent with that from NA48.

We present a search for standard model Higgs boson production in association with a $W$ boson in proton-antiproton collisions ($p\overline{p}\to W^{\pm }H\to \ell \nu b\overline{b}$) at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector which correspond to an integrated luminosity of approximately $1{\mathrm{fb}}^{-1}$. We select events consistent with a signature of a single lepton ($e^{\pm }/{\mu }^{\pm }$), missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method and a neural network filter technique. The observed number of events and the dijet mass distributions are consistent with the standard model background expectations, and we set 95% confidence level upper limits on the production cross section times branching ratio ranging from 3.9 to 1.3 pb for Higgs boson masses from 110 to $150\mathrm{GeV}/c^2$, respectively.

We have carried out a Schrodinger functional calculation for the SU(3) lattice gauge theory with two flavors of Wilson fermions in the sextet representation of the gauge group. We find that the discrete beta function, which governs the change in the running coupling under a discrete change of spatial scale, changes sign when the Schrodinger functional renormalized coupling is in the neighborhood of $g^2=2.0$. The simplest explanation is that the theory has an infrared-attractive fixed point, but more complicated possibilities are allowed by the data. While we compare rescalings by factors of 2 and $4/3$, we work at a single lattice spacing.

Using a sample of $2.59\times {10}^7$ $\psi (2S)$ decays collected by the CLEO-c detector, we present results of a study of ${\chi }_{cJ}$ ($J=0$, 1, 2) decays into baryon-antibaryon final states. We present the world’s most precise measurements of the ${\chi }_{cJ}\to p\overline{p}$ and ${\chi }_{cJ}\to \Lambda \overline{\Lambda }$ branching fractions, and the first measurements of ${\chi }_{c0}$ decays to other hyperons. These results illuminate the decay mechanism of the ${\chi }_c$ states.