We derive boundary conditions for the covariant open string corresponding to D-branes in an Hpp-wave by requiring kappa-symmetry of its bulk action. Both half-supersymmetric and quarter-supersymmetric branes are seen to arise in this way, and the analysis furthermore agrees fully with the existing probe brane and supergravity computations. We elaborate on the origin of dynamical and kinematical supersymmetries from the covariant point of view. In particular we focus on the D-string which only preserves half of the dynamical supersymmetries and none of the kinematical ones. We discuss its origin in ${\mathrm{AdS}}_5\times {\mathrm{S}}^5$ and its world-volume spectrum.

In this paper we review and study several different features of anisotropic spherical star models. We first show that if the radial pressure is larger than the tangential pressure, then the radial pressure is also larger than the corresponding pressure for a fiducial isotropic model with the same mass function and total mass, while the opposite holds if the tangential pressure is larger than the radial one. If, in the first case, we further impose an energy condition, then using previous results (maximum mass for an isotropic spherically symmetric star) we obtain a value for the maximum possible redshift at the surface of the star. These results are then applied in the analysis of a specific example given by the Bower-Liang model. Finally, imposing energy conditions, we study the maximum possible value for the redshift, independently of whether the radial or the tangential pressure is larger than the other. We first reobtain Ivanov’s bound for the ratio of mass to radius, but using a different approach, and then we find a refinement of this bound, expressing it as a function of the ratio between the central and the average energy density.

The braneworld model of Dvali, Gabadadze, and Porrati (DGP) is a theory where gravity is modified at large distances by the arrested leakage of gravitons off our four-dimensional universe. Cosmology in this model has been shown to support both “conventional” and exotic explanations of the dark energy responsible for today’s cosmic acceleration. We present new results for the gravitational field of a clustered matter source on the background of an accelerating universe in DGP braneworld gravity, and articulate how these results differ from those of general relativity. In particular, we show that orbits nearby a mass source suffer a universal anomalous precession as large as $\pm 5\mu \mathrm{a}\mathrm{s}/\mathrm{y}\mathrm{e}\mathrm{a}\mathrm{r},$ dependent only on the graviton’s effective linewidth and the global geometry of the full, five-dimensional universe. Thus, this theory offers a local gravity correction sensitive to factors that dictate cosmological history.

The new measurement of the anomalous magnetic moment of the muon by the Brookhaven AGS experiment 821 again shows a discrepancy with the standard model value. We investigate the consequences of these new data for neutralino dark matter, updating and extending our previous work [E. A. Baltz and P. Gondolo, Phys. Rev. Lett. 86, 5004 (2001)]. The measurement excludes the standard model value at $3.0\sigma$ confidence, assuming the evaluation using the hadronic $e^{+}{e}^{-}$ cross section (the $\tau$ decay evaluation yields only a $1.6\sigma$ discrepancy). We analyze a phenomenological set of supersymmetric models with gaugino mass unification imposed but without a priori constraints on the Higgs sector. Taking the discrepancy as a sign of supersymmetry, we find that the lightest superpartner must be relatively light and it must have a relatively high elastic scattering cross section with nucleons, which brings it almost within reach of proposed direct dark matter searches. The SUSY signal from neutrino telescopes correlates fairly well with the elastic scattering cross section. The rate of cosmic ray antideuterons tends to be large in the allowed models, but the constraint has little effect on the rate of gamma ray lines. We stress that being more conservative may eliminate the discrepancy, but it does not eliminate the possibility of high astrophysical detection rates.

There exists a one complex parameter family of de Sitter invariant vacua, known as α vacua. In the context of slow roll inflation, we show that all but the Bunch-Davies vacuum generates unacceptable production of high energy particles at the end of inflation. As a simple model for the effects of trans-Planckian physics, we go on to consider non–de Sitter invariant vacua obtained by patching modes in the Bunch-Davies vacuum above some momentum scale $M_c,$ with modes in an α vacuum below $M_c.$ Choosing $M_c$ near the Planck scale $M_{\mathrm{Pl}},$ we find acceptable levels of hard particle production, and corrections to the cosmic microwave perturbations at the level of ${\mathrm{HM}}_{\mathrm{Pl}}{/M}_c^2,$ where H is the Hubble parameter during inflation. More general initial states of this type with $H\ll M_c\ll M_{\mathrm{Pl}}$ can give corrections to the spectrum of cosmic microwave background perturbations at order 1. The parameter characterizing the α vacuum during inflation is a new cosmological observable.

A new experiment to test for the time independence of the fine structure constant α is proposed. The experiment utilizes orthogonally polarized transverse electric and transverse magnetic whispering gallery modes in a single sapphire resonator tuned to similar frequencies. When configured as a dual mode sapphire clock, we show that the anisotropy of sapphire makes it is possible to undertake a sensitive measurement from the beat frequency between the two modes. At infrared frequencies this is possible due to the different effect of the lowest phonon frequency on the two orthogonally polarized modes. At microwave frequencies we show that the phonon effect is too small. We show that the electron spin resonance of paramagnetic impurities (such as ${\mathrm{Cr}}^{3+})$ in the lattice affects only one polarization with an ${\alpha }^6$ dependence. This enables an enhancement of the sensitivity to temporal changes in α at microwave frequencies.

We calculate the CP-violating asymmetries $A\left({\Lambda }_{-}^0\right)$ and $A\left({\Xi }_{-}^{-}\right)$ in nonleptonic hyperon decay within the standard model using the framework of heavy-baryon chiral perturbation theory $\left(\chi \mathrm{PT}\right).\mathrm{}$ We identify those terms that correspond to previous calculations and discover several errors in the existing literature. We present a new result for the lowest-order (in $\chi \mathrm{PT})$ contribution of the penguin operator to these asymmetries, as well as an estimate for the uncertainty of our result that is based on the calculation of the leading nonanalytic corrections.

A comparison of two appropriately chosen screening masses of color singlet operators in the pure glue QCD plasma indicates that at sufficiently high temperature it contains a weakly interacting massive quasiparticle with the quantum numbers of the electric gluon. Still in the deconfined phase, but closer to $T_c,$ the same mass ratio is similar to that at zero temperature, indicating that the propagating modes are more glueball-like, albeit with a lower scale for the masses. We observe a continuity between these two regimes.

We extend and test the method of Dijkgraaf and Vafa for computing the superpotential of $\mathcal{N}=1\mathrm{}$ theories to include flavors in the fundamental representation of the gauge group. This amounts to computing the contribution to the superpotential from surfaces with one boundary in the matrix integral. We compute exactly the effective superpotential for the case of the gauge group ${U(N}_c),$ $N_f$ massive flavor chiral multiplets in the fundamental and one massive chiral multiplet in the adjoint, together with a Yukawa coupling. We compare up to sixth order with the result obtained by standard field theory techniques in the already nontrivial case of $N_c=2\mathrm{}$ and $N_f=1.\mathrm{}$ The agreement is perfect.

We present a study of a three neutrino flavor transition model based on supersymmetric interactions that violate R parity. These interactions induce flavor violating scattering reactions between solar matter and neutrinos. The model does not contain any vacuum mass or mixing angle for the first generation neutrino. Instead, the effective mixing in the first generation is induced via the new interactions. The model provides a natural interpretation of the atmospheric neutrino anomaly, and is consistent with reactor experiments. We determine all R-parity violating couplings which can contribute to the effective neutrino oscillations, and summarize the present laboratory bounds. Independent of the specific nature of the (supersymmetric) flavor violating model, the experimental data on the solar neutrino rates and the recoil electron energy spectrum are inconsistent with the theoretical predictions. The confidence level of the ${\chi }^2$ analysis ranges between $\sim {10}^{-4}$ and $\sim {10}^{-3}.$ The incompatibility arises because we cannot simultaneously accommodate the new SNO results together with the recoil electron energy spectrum from Super-Kamiokande in our model. We conclude that a nonvanishing vacuum mixing angle for the first generation neutrino is necessary in our model. We expect this also to apply to the solutions based on other flavor violating interactions having constraints of the same order of magnitude.

Nucleon-nucleon scattering is studied to next-to-leading order in a partially quenched extension of an effective field theory used to describe multi-nucleon systems in QCD. The partially quenched nucleon-nucleon amplitudes will play an important role in relating lattice simulations of the two-nucleon sector to nature.

We investigate the effect induced by variations in the density profile of the Earth’s interior using a long-baseline neutrino oscillation experiment. First, we point out two facts. (i) The most essential part of the matter profile is the first Fourier mode of the matter profile function; and (ii) the Earth models based on the study of seismology include a large uncertainty for the first Fourier mode. Next, we show that there is a strong correlation between the average density value and the first Fourier coefficient in the analysis of the oscillation probability. This means that the matter profile effect induces an added uncertainty for the average matter parameter. Taking into account this extra uncertainty, we make numerical calculations for the sensitivity to the $\mathrm{CP}$ violation search and show that $\mathrm{CP}$ sensitivity is impaired by this added uncertainty within a large $U_{e3\mathrm{}}$ region.

We study the optimization of nonperturbative renormalization group equations truncated both in fields and derivatives. On the example of the Ising model in three dimensions, we show that the principle of minimal sensitivity can be unambiguously implemented at order ${\partial }^2$ of the derivative expansion. This approach allows us to select optimized cutoff functions and to improve the accuracy of the critical exponents $\nu$ and $\eta .$ The convergence of the field expansion is also analyzed. We show in particular that its optimization does not coincide with optimization of the accuracy of the critical exponents.

We consider the interacting system of $D=4,N=1\mathrm{}$ supergravity and the Brink-Schwarz massless superparticle as described by the sum of their superfield actions, and derive the complete set of superfield equations of motion for the coupled dynamical system. These include source terms given by derivatives of a vector superfield current density with support on the worldline. This current density is constructed from the spin $3/2$ and spin $2$ current density “prepotentials.” We analyze the gauge symmetry of the coupled action and show that it is possible to fix the gauge in such a way that the equations of motion reduce to those of the supergravity-bosonic particle coupled system.

In the minimal supersymmetric standard model (MSSM) with complex parameters, supersymmetric loop effects can lead to $\mathrm{CP}$ violation. We calculate the rate asymmetries of decays of charginos into the lightest neutralino and a W boson on the basis of the most important loop contributions in the third generation squark sector. It turns out that the $\mathrm{CP}$ violating asymmetries can be a few percent in typical regions of the parameter space of the MSSM. These processes would provide very promising channels for probing $\mathrm{CP}$ violation in the MSSM at future high-energy colliders.

In models in which all of the standard model fields live in extra “universal” dimensions, the lightest Kaluza-Klein (KK) particle can be stable. Calculations of the one-loop radiative corrections to the masses of the KK modes suggest that the identity of the lightest KK particle (LKP) is mostly the first KK excitation of the hypercharge gauge boson. This LKP is a viable dark matter candidate with an ideal present-day relic abundance if its mass is moderately large, between 600 to 1200 GeV. Such weakly interacting dark matter particles are expected to become gravitationally trapped in large bodies, such as the Sun, and annihilate into neutrinos or other particles that decay into neutrinos. We calculate the annihilation rate, neutrino flux and the resulting event rate in present and future neutrino telescopes. The relatively large mass implies that the neutrino energy spectrum is expected to be well above the energy threshold of AMANDA and IceCube. We find that the event rate in IceCube is between a few to tens of events per year.

We show that initial-state interactions contribute to the $\cos 2\phi$ distribution in unpolarized Drell-Yan lepton pair production $\mathrm{pp}$ and $p\overline{p}\to {\mathcal{l}}^{+}{\mathcal{l}}^{-}X,$ without suppression. The asymmetry is expressed as a product of chiral-odd distributions $h_1^{\perp }{(x}_1,{\mathit{p}}_{\perp }^2)\times h_1^{\perp }{(x}_2,{\mathit{k}}_{\perp }^2),$ where the quark-transversity function $h_1^{\perp }(x,{\mathit{p}}_{\perp }^2)$ is the transverse momentum dependent, light-cone momentum distribution of transversely polarized quarks in an unpolarized proton. We compute this (naive) T-odd and chiral-odd distribution function and the resulting $\cos 2\phi$ asymmetry explicitly in a quark-scalar diquark model for the proton with initial-state gluon interaction. In this model the function $h_1^{\perp }(x,{\mathit{p}}_{\perp }^2)$ equals the T-odd (chiral-even) Sivers effect function $f_{1T}^{\perp }(x,{\mathit{p}}_{\perp }^2).\mathrm{}$ This suggests that the single-spin asymmetries in the semi-inclusive deep inelastic scattering and the Drell-Yan process are closely related to the $\cos 2\phi$ asymmetry of the unpolarized Drell-Yan process, since all can arise from the same underlying mechanism. This provides new insight regarding the role of the quark and gluon orbital angular momentum as well as that of initial- and final-state gluon exchange interactions in hard QCD processes.

We evaluate the decay rate of the uniformly accelerated proton. We obtain an analytic expression for the inverse beta decay process caused by the acceleration. We evaluate the decay rate both from the inertial frame and from the accelerated frame where we should consider thermal radiation by the Unruh effect. We explicitly check that the decay rates obtained in both frames coincide with each other.

The anti–de Sitter C metric (AdS C metric) is characterized by a quite interesting new feature when compared with the C metric in flat or de Sitter backgrounds. Indeed, contrary to what happens in these two last exact solutions, the AdS C metric only describes a pair of accelerated black holes if the acceleration parameter satisfies $A>\mathrm{}1/\mathcal{l},$ where $\mathcal{l}$ is the cosmological length. The two black holes cannot interact gravitationally and their acceleration is totally provided by the pressure exerted by a strut that pushes the black holes apart. Our analysis is based on the study of the causal structure, on the description of the solution in the AdS 4-hyperboloid in a 5D Minkowski spacetime, and on the physics of the strut. We also analyze the cases $A=1/\mathcal{l}$ and $A<\mathrm{}1/\mathcal{l}$ that represent a single accelerated black hole in the AdS background.

Current observational data favor cosmological models which differ from the standard model due to the presence of some form of dark energy and, perhaps, by additional contributions to the more familiar dark matter. Primordial nucleosynthesis provides a window on the very early evolution of the universe and constraints from big bang nucleosynthesis (BBN) can bound the parameters of models for dark matter or energy at redshifts of the order of ten billion. The spectrum of temperature fluctuations imprinted on the cosmic microwave background (CMB) radiation opens a completely different window on the universe at epochs from redshifts of the order of ten thousand to nearly the present. The CMB anisotropy spectrum provides constraints on new physics which are independent of and complementary to those from BBN. Here we consider three classes of models for the dark matter or energy: extra particles which were relativistic during the early evolution of the universe $\left(“X”\right);$ quintessence models involving a minimally coupled scalar field $\left(“Q”\right);$ models with a non-minimally coupled scalar field which modify the strength of gravity during the early evolution of the universe $\left(“G”\right).\mathrm{}$ We constrain the parameters of these models using data from BBN and the CMB and identify the allowed regions in their parameter spaces consistent with the more demanding joint BBN and CMB constraints. For $“X”$ and $“Q”$ such consistency is relatively easy to find; it is more difficult for the $“G”$ models with an inverse power law potential for the scalar field.