The acoustic peak in the cosmic microwave background power spectrum is sensitive to causal processes and cosmological parameters in the early universe up to the time of last scattering. We provide limits on correlated spatial variations of the peak height and peak position and interpret these as constraints on the spatial variation of the cosmological parameters (baryon density, cold dark matter density, and cosmological constant as well as the amplitude and tilt of the original fluctuations). We utilize recent work of Hansen, Banday, and Górski who have studied the spatial isotropy of the power spectrum as measured by WMAP by performing the power spectrum analysis on smaller patches of the sky. We find that there is no statistically significant correlated asymmetry of the peak. Hansen, Banday, and Górski have also provided preliminary indications of a preferred direction in the lower angular momentum range ($\ell \sim 2–40$) and we show how possible explanations of this asymmetry are severely constrained by the data on the acoustic peak. Finally we show a possible non-Gaussian feature in the data, associated with a difference in the northern and southern galactic hemispheres.

If an exact $\mu \leftrightarrow \tau$ symmetry is the explanation of the maximal atmospheric neutrino mixing angle, it has interesting implications for the origin of matter via leptogenesis in models where small neutrino masses arise via the seesaw mechanism. For seesaw models with two right-handed neutrinos $(N_{\mu },N_{\tau })$, lepton asymmetry vanishes in the exact $\mu \leftrightarrow \tau$ symmetric limit, even though there are nonvanishing Majorana phases in the neutrino mixing matrix. On the other hand, for three right-handed neutrino models, lepton asymmetry is nonzero and is given directly by the solar mass difference square. We also find an upper bound on the lightest neutrino mass.

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity $86{\mathrm{p}\mathrm{b}}^{-1}$, were recorded by the CDF Experiment for $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV. This study tests a model of higher order QCD processes that result in gluon emission and may give some indication of the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be $466\pm 3(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}.{)}_{-70}^{+207}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}.)$ pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.

We consider a deformation of $\mathrm{N}=1$ four dimensional Minkowski superspace where odd coordinates ${\theta }^{\alpha }$ do not anticommute. We define supersymmetric and associative star product and show how the remaining (anti)commutation relations among the superspace coordinates are modified. In particular, the even coordinates do not commute as well. We also study chiral and vector superfields and their interactions. Suprisingly we find that ordinary undeformed $\mathrm{N}=1$ supersymmetric field theories are compatible with the deformed supersymmetry considered.

We investigate the split supersymmetry (SUSY) scenario recently proposed by Arkani-Hamed and Dimopoulos, where the scalars are heavy but the fermions are within the TeV range. We show that the sparticle spectrum in such a case crucially depends on the specific details of the mechanism underlying the SUSY breaking scheme, and the accelerator signals are also affected by it. In particular, we demonstrate in the context of a braneworld-inspired model, used as illustration in the original work, that a new fermion ${\psi }_X$, arising from the SUSY breaking sector, is shown to control low-energy phenomenology in several cases. Also, SUSY signals are characterized by the associated production of the light neutral Higgs. In an alternative scenario where the gauginos are assumed to propagate in the bulk, we find that gluinos can be heavy and short-lived, and the SUSY breaking scale can be free of cosmological constraints.

We calculate the two body Higgs boson decays in the framework of the littlest Higgs model. The decay $H\to \gamma Z$ is computed at one-loop-level and, using previous results, we evaluate the branching fractions in the framework of the littlest Higgs model. A wide range of the space parameter of the model is considered and possible deviations from the standard model are explored.

The masses of baryons containing a heavy-quark are calculated to next-to-leading-order in partially quenched heavy hadron chiral perturbation theory. Calculations are performed for three light flavors in the isospin limit and additionally for two light nondegenerate flavors. The results presented are necessary for extrapolating lattice QCD and partially quenched lattice QCD calculations of the heavy hadron masses.

We evaluate the complete spectrum of the $B_c$ mesons, below the open flavor $BD$ threshold, in a Bethe-Salpeter model. We make predictions for the radiative decay widths of the $B_c$ excited states. We compare our results with those of other models.

We argue a factorization formula for semi-inclusive deep-inelastic scattering with hadrons in the current fragmentation region detected at low transverse momentum. To facilitate the factorization, we introduce the transverse-momentum dependent parton distributions and fragmentation functions with gauge links slightly off the light cone, and with soft-gluon radiations subtracted. We verify the factorization to one-loop order in perturbative quantum chromodynamics and argue that it is valid to all orders in perturbation theory.

We present a new measurement of the inclusive and differential production cross sections of $J/\psi$ mesons and $b$ hadrons in proton-antiproton collisions at $\sqrt{s}=1960\mathrm{G}\mathrm{e}\mathrm{V}$. The data correspond to an integrated luminosity of $39.7{\mathrm{p}\mathrm{b}}^{-1}$ collected by the CDF run II detector. We find the integrated cross section for inclusive $J/\psi$ production for all transverse momenta from 0 to $20\mathrm{G}\mathrm{e}\mathrm{V}/c$ in the rapidity range $|y|<0.6$ to be $4.08\pm 0.02(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{-0.33}^{+0.36}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mu \mathrm{b}$. We separate the fraction of $J/\psi$ events from the decay of the long-lived $b$ hadrons using the lifetime distribution in all events with $p_T(J/\psi )>1.25\mathrm{G}\mathrm{e}\mathrm{V}/c$. We find the total cross section for $b$ hadrons, including both hadrons and antihadrons, decaying to $J/\psi$ with transverse momenta greater than $1.25\mathrm{G}\mathrm{e}\mathrm{V}/c$ in the rapidity range $|y(J/\psi )|<0.6$ is $0.330\pm 0.005(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{-0.033}^{+0.036}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mu \mathrm{b}$. Using a Monte Carlo simulation of the decay kinematics of $b$ hadrons to all final states containing a $J/\psi$, we extract the first measurement of the total single $b$-hadron cross section down to zero transverse momentum at $\sqrt{s}=1960\mathrm{G}\mathrm{e}\mathrm{V}$. We find the total single $b$-hadron cross section integrated over all transverse momenta for $b$ hadrons in the rapidity range $|y|<0.6$ to be $17.6\pm 0.4(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}{)}_{-2.3}^{+2.5}(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mu \mathrm{b}$.

Dark energy constraints have forced viable alternatives that differ substantially from a cosmological constant $\Lambda$ to have an equation of state $w$ that evolves across the phantom divide set by $\Lambda$. Naively, crossing this divide makes the dark energy gravitationally unstable, a problem that is typically finessed by unphysically ignoring the perturbations. While this procedure does not affect constraints near the favored cosmological constant model it can artificially enhance the confidence with which alternative models are rejected. Similar to the general problem of stability for $w<0$, the solution lies in the internal degrees of freedom in the dark energy sector. We explicitly show how to construct a two scalar field model that crosses the phantom divide and mimics the single field behavior on either side to substantially better than $1\%$ in all observables. It is representative of models where the internal degrees of freedom keep the dark energy smooth out to the horizon scale independently of the equation of state.

Supersymmetric black ring solutions of five-dimensional supergravity coupled to an arbitrary number of vector multiplets are constructed. The solutions are asymptotically flat and describe configurations of concentric black rings which have regular horizons with topology $S^1\times S^2$ and no closed timelike curves at the horizons.

The tetrad partial differential equations formulated by Buchman and Bardeen for vacuum gravity are shown to be well posed by calculation of the Cartan characters of an associated exterior differential system. Gauge specializations are discussed. A Cartan 4-form is found for this field theory, together with its intrinsic version the Lagrangian density.

We have studied the evolution of the massless scalar field propagating in a time-dependent charged Vaidya black hole background. A generalized tortoise coordinate transformation was used to study the evolution of the massless scalar field. It is shown that, for the slowest damped quasinormal modes, the approximate formulas in the stationary Reissner-Nordström black hole turn out to be a reasonable prescription, showing that results from quasinormal mode analysis are rather robust.

Two photons can annihilate into a neutral pionlike resonance via the anomaly coupling, just like ${\pi }^0\gamma \gamma$ in QCD. In some strongly interacting electroweak symmetry breaking models, e.g., technicolor type models, there often exist neutral pionlike resonances. TeV photon colliders have a strong capability to discover such particles, because the standard model background in photon scattering goes through box diagrams and is therefore highly suppressed. In this study, we perform a signal-background comparison. We show that $e^{+}{e}^{-}$ linear colliders running in $\gamma \gamma$ mode can discover such neutral pionlike resonances with a decent sensitivity.

We consider $O({\alpha }_s)$ corrections to the squared masses of the pseudo-Goldstone excitations about the ground state of dense quark matter. We show that these contributions tend to destabilize the vacuum, leading to a surprisingly complex phase structure for quark matter as a function of quark mass, even for small ${\alpha }_s$. In particular we find two new phases of CFL quark matter possibly relevant for the real world, for which ${\overline{\theta }}_{\mathrm{Q}\mathrm{C}\mathrm{D}}=\pi /2$.

We present joint threshold and recoil resummed transverse momentum distributions for heavy quark hadroproduction, at next-to-leading logarithmic accuracy. We study the dependence of these distributions on the production channel, the color configurations and the differences with the pure threshold-resummed distribution.

In this article we develop a physical interpretation for the deformed (doubly) special relativity theories (DSRs), based on a modification of the theory of measurement in special relativity. We suggest that it is useful to regard the DSRs as reflecting the manner in which quantum gravity effects induce Planck-suppressed distortions in the measurement of the “true” energy and momentum. This interpretation provides a framework for the DSRs that is manifestly consistent, nontrivial, and in principle falsifiable. However, it does so at the cost of demoting such theories from the level of fundamental physics to the level of phenomenological models—models that should in principle be derivable from whatever theory of quantum gravity one ultimately chooses to adopt.

We discuss the realization of metastable gravity on classical defects in infinite-volume extra dimensions. In dilatonic Einstein gravity, it is found that the existence of metastable gravity on the defect core requires violation of the dominant energy condition for codimension $N_{\mathrm{c}}=2$ defects. This is illustrated with a detailed analysis of a six-dimensional hyperstring minimally coupled to dilaton gravity. We present the general conditions under which a codimension $N_{\mathrm{c}}>2$ defect admits metastable modes, and find that they differ from lower codimensional models in that, under certain conditions, they do not require violation of energy conditions to support quasilocalized gravity.

This work presents a reduced ${\chi }_{\nu }^2$ test to search for non-Gaussian signals in the cosmic microwave background radiation (CMBR) TT power spectrum of recent CMBR data, Wilkinson Anisotropy Microwave Probe, Arcminute Cosmology Bolometer Array Receiver, and Cosmic Background Imager data sets, assuming a mixed density field including adiabatic and isocurvature fluctuations. We assume a skew positive mixed model with adiabatic inflation perturbations plus additional isocurvature perturbations possibly produced by topological defects. The joint probability distribution used in this context is a weighted combination of Gaussian and non-Gaussian random fields. Results from simulations of CMBR temperature for the mixed field show a distinct signature in CMB power spectrum for very small deviations ($\sim 0.1\%$) from a pure Gaussian field, and can be used as a direct test for the nature of primordial fluctuations. A reduced ${\chi }_{\nu }^2$ test applied on the most recent CMBR observations reveals that an isocurvature fluctuations field is not ruled out and indeed permits a very good description for a flat geometry $\Lambda$-CDM Universe, ${\chi }_{930}^2\sim 1.5$, rather than the simple inflationary standard model with ${\chi }_{930}^2\sim 2.3$. This result may looks is particular discrepant with the reduced ${\chi }^2$ of 1.07 obtained with the same model in Spergel et al. [Astrophys. J. 148, 175 (2003)] for temperature only, however, our work is restricted to a region of the parameter space that does not include the best fit model for TT only of Spergel et al..