We construct a classical nonrelativistic string model in $3+1$ dimensions. The model contains a spurion tensor field that is responsible for the noncommutative structure of the model. Under double-dimensional reduction the model reduces to the exotic nonrelativistic particle in $2+1$ dimensions.

We consider a Yang-Mills-Higgs theory with spontaneous symmetry breaking of the gauge group $G\to U(1{)}^r\to C_G$, with $C_G$ being the center of $G$. We study two vacua solutions of the theory which produce this symmetry breaking. We show that for one of these vacua, the theory in the Coulomb phase has the mass spectrum of particles and monopoles which is exactly the same as the mass spectrum of particles and solitons of two-dimensional affine Toda field theory, for suitable coupling constants. That result holds also for $\mathcal{N}=4$ super Yang-Mills theories. On the other hand, in the Higgs phase, we show that for each of the two vacua the ratio of the tensions of the BPS $Z_N$ strings satisfy either the Casimir scaling or the sine law scaling for $G=SU(N)$. These results are extended to other gauge groups: for the Casimir scaling, the ratios of the tensions are equal to the ratios of the quadratic Casimir constant of specific representations; for the sine law scaling, the tensions are proportional to the components of the left Perron-Frobenius eigenvector of Cartan matrix $K_{ij}$ and the ratios of tensions are equal to the ratios of the soliton masses of affine Toda field theories.

We consider an $\mathcal{N}=2$ supersymmetric $SU(2)\times U(1)$ gauge theory with $N_f=2$ massless flavors and a Fayet-Iliopoulos (FI) term. In the presence of the FI term, supersymmetry is spontaneously broken at tree level (on the Coulomb branch), leaving a pseudoflat direction in the classical potential. This vacuum degeneracy is removed once quantum corrections are taken into account. Because of the $SU(2)$ gauge dynamics, the effective potential exhibits a local minimum at the dyon point, where not only supersymmetry but also $U(1{)}_R$ symmetry is broken, while a supersymmetric vacuum would be realized toward infinity with the runaway behavior of the potential. This local minimum is found to be parametrically long-lived. Interestingly, from a phenomenological point of view, in this metastable vacuum the massive hypermultiplets inherent in the theory play the role of the messenger fields in the gauge mediation scenario, when the standard model gauge group is embedded into their flavor symmetry.

Neutrinos streaming off a supernova core transform collectively by neutrino-neutrino interactions, leading to “spectral splits” where an energy $E_{\mathrm{split}}$ divides the transformed spectrum sharply into parts of almost pure but different flavors. We present a detailed description of the spectral-split phenomenon which is conceptually and quantitatively understood in an adiabatic treatment of neutrino-neutrino effects. Central to this theory is a self-consistency condition in the form of two sum rules (integrals over the neutrino spectra that must equal certain conserved quantities). We provide explicit analytic and numerical solutions for various neutrino spectra. We introduce the concept of the adiabatic reference frame and elaborate on the relative adiabatic evolution. Violating adiabaticity leads to the spectral split being “washed out.” The sharpness of the split appears to be represented by a surprisingly universal function.

We derive the energy asymmetry given the protoneutron star during the time when the neutrino sphere is near the surface of the protoneutron star, using the modified Urca process. The electrons produced with the antineutrinos are in Landau levels due to the strong magnetic field, and this leads to asymmetry in the neutrino momentum, and a pulsar kick. The magnetic field must be strong enough for a large fraction of the electrons to be in the lowest Landau level; however, there is no direct dependence of our pulsar velocity on the strength of the magnetic field. Our main prediction is that the large pulsar kicks start at about 10 s and last for about 10 s, with the corresponding neutrinos correlated with the direction of the magnetic field. We predict a pulsar velocity of $1.03\times {10}^{-4}(T/{10}^{10}\mathrm{K}{)}^7\mathrm{km}/s$, which reaches $1000\mathrm{km}/s$ if $T\simeq {10}^{11}\mathrm{K}$.

$N=2$ supersymmetric Yang-Mills theory with flavor hypermultiplets at finite temperature and in the ${\mathrm{dS}}_4$ space is studied for finite quark number density ($n_b$) by a dual supergravity background with nontrivial dilaton and axion. The quarks and their number density $n_b$ are introduced by embedding a probe D7 brane. We find a critical value of the chemical potential at the limit of $n_b=0$, and it coincides with the effective quark mass given in each theory for $n_b=0$. At this point, a transition of the D7 embedding configurations occurs between their two typical ones. The phase diagrams of this transition are shown in the plane of chemical potential versus temperature and cosmological constant for Yang-Mills theory at finite temperature and in ${\mathrm{dS}}_4$, respectively. In this phase transition, the order parameter is considered as $n_b$. This result seems to be reasonable since both theories are in the quark deconfinement phase.

We compute the one loop corrections from quantum gravity to the self-mass-squared of a massless, minimally coupled scalar on a locally de Sitter background. The calculation was done using dimensional regularization and renormalized by subtracting fourth order BPHZ (Bogoliubov-Parasiuk-Hepp-Zimmerman) counterterms. Our result should determine whether quantum gravitational loop corrections can significantly alter the dynamics of a scalar inflaton.

Full general relativity requires that chaos indicators should be invariant in various spacetime coordinate systems for a given relativistic dynamical problem. On the basis of this point, we calculate the invariant Lyapunov exponents (LEs) for one of the spinning compact binaries in the conservative second post-Newtonian (2PN) Lagrangian formulation without the dissipative effects of gravitational radiation, using the two-nearby-orbits method with projection operations and with coordinate time as an independent variable. It is found that the actual source leading to zero LEs in one paper [J. D. Schnittman and F. A. Rasio, Phys. Rev. Lett. 87, 121101 (2001)] but to positive LEs in the other [N. J. Cornish and J. Levin, Phys. Rev. Lett. 89, 179001 (2002)] does not mainly depend on rescaling, but is due to two slightly different treatments of the LEs. It takes much more CPU time to obtain the stabilizing limit values as reliable values of LEs for the former than to get the slopes (equal to LEs) of the fit lines for the latter. Due to coalescence of some of the black holes, the LEs from the former are not an adaptive indicator of chaos for comparable mass compact binaries. In this case, the invariant fast Lyapunov indicator (FLI) of two-nearby orbits, as a very sensitive tool to distinguish chaos from order, is worth recommending. As a result, we do again find chaos in the 2PN approximation through different ratios of FLIs varying with time. Chaos cannot indeed be ruled out in real binaries.

We found a new branch of solutions in Freund-Rubin type flux compactifications. The geometry of these solutions is described as the external space which has a de Sitter symmetry and the internal space which is topologically spherical. However, it is not a simple form of ${\mathrm{dS}}_p\times S^q$ but a warped product of de Sitter space and a deformed sphere. We explicitly constructed numerical solutions for a specific case with $p=4$ and $q=4$. We show that the new branch of solutions emanates from the marginally stable solution in the branch of ${\mathrm{dS}}_4\times S^4$ solutions.

Binary black-hole systems with spins aligned with the orbital angular momentum are of special interest, as studies indicate that this configuration is preferred in nature due to non-vacuum environmental interactions, as well as post-Newtonian (PN) spin-orbit couplings. If the spins of the two bodies differ, there can be a prominent beaming of the gravitational radiation during the late plunge, causing a recoil of the final merged black hole. In this paper we perform an accurate and systematic study of recoil velocities from a sequence of equal-mass black holes whose spins are aligned with the orbital angular momentum, and whose individual spins range from $a=+0.584$ to $-0.584$. In this way we extend and refine the results of a previous study which concentrated on the antialigned portion of this sequence, to arrive at a consistent maximum recoil of $448\pm 5\mathrm{km}/\mathrm{s}$ for antialigned models as well as to a phenomenological expression for the recoil velocity as a function of spin ratio. Quite surprisingly, this relation highlights a nonlinear behavior, not predicted by the PN estimates, and can be readily employed in astrophysical studies on the evolution of binary black holes in massive galaxies. An essential result of our analysis, without which no systematic behavior can be found, is the identification of different stages in the waveform, including a transient due to lack of an initial linear momentum in the initial data. Furthermore, by decomposing the recoil computation into coupled modes, we are able to identify a pair of terms which are largely responsible for the kick, indicating that an accurate computation can be obtained from modes up to $\ell =3$. Finally, we provide accurate measures of the radiated energy and angular momentum, finding these to increase linearly with the spin ratio, and derive simple expressions for the final spin and the radiated angular momentum which can be easily implemented in $N$-body simulations of compact stellar systems. Our code is calibrated with strict convergence tests and we verify the correctness of our measurements by using multiple independent methods whenever possible.

We investigate the modifications to predictions for the abundances of light elements from standard big-bang nucleosynthesis when exotic late-decaying particles with lifetimes exceeding $\sim 1\sec$ are prominent in the early Universe. Utilizing a model-independent analysis of the properties of these long-lived particles, we identify the parameter space associated with models that are consistent with all observational data and hence resolve the much discussed discrepancies between observations and theoretical predictions for the abundances of ${}^7\mathrm{Li}$ and ${}^6\mathrm{Li}$.

Recent measurements of $|V_{us}|$ from kaon decays strongly support the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. The unitarity provides a stringent constraint on the parameter space of the nonuniversal gauge interaction model based on the separate $SU(2{)}_L$ gauge group acting on the third generation fermions. I show that this constraint is stronger than those from the CERN LEP and SLC data and low-energy experiment data.

We present a simple texture that predicts the cotangent of the solar neutrino mixing angle to be equal to the golden ratio. This prediction is $1.4\sigma$ below the present best-fit value and final SNO and KamLAND data could discriminate it from tri-bimaximal mixing. The neutrino mass matrix is invariant under a $Z_2\otimes {\mathrm{Z}}_2^{\prime }$ symmetry: that geometrically is a reflection along the diagonal of the golden rectangle. Assuming an analogous structure in the quark sector suggests a golden prediction for the Cabibbo angle, ${\theta }_C=\pi /4-{\theta }_{12}\approx 13.3°$, up to the uncertainties comparable to $V_{ub}$.

Using $14.0\times {10}^6\psi (2S)$ events collected with the BES-II detector, the $C$-parity violating process $J/\psi \to \gamma \gamma$ via $\psi (2S)\to {\pi }^{+}{\pi }^{-}J/\psi$ is studied. We determine a new upper limit for the $J/\psi \to \gamma \gamma$ branching ratio of $\mathcal{B}(J/\psi \to \gamma \gamma )<2.2\times {10}^{-5}$ at the 90% C.L., which is about 20 times lower than the previous measurement.

We show a natural form of the interaction between the unparticle and supersymmetry. Using the couplings of the unparticle to supersymmetry presented, as examples, we calculate the differential decay rates for the processes $\tilde{f}\to f+{\mathcal{U}}_{3/2}$, ${\tilde{\chi }}^0\to \gamma +{\mathcal{U}}_{3/2}$, ${\tilde{\chi }}^{\pm }\to W^{\pm }+{\mathcal{U}}_{3/2}$ and ${\tilde{\chi }}^0\to Z^0+{\mathcal{U}}_{3/2}$. Finally, we discuss the phenomenological implication of our results and give some comments.

We discuss apparent paradoxes regarding the location of the zeros of the partition function in the complex $\beta$ plane (Fisher’s zeros) of a pure $SU(2)$ lattice gauge theory in 4 dimensions. We propose a new criterion to draw the region of the complex $\beta$ plane where reweighting methods can be trusted when the density of states is almost but not exactly Gaussian. We propose new methods to infer the existence of zeros outside of this region. We demonstrate the reliability of these proposals with quasi-Gaussian Monte Carlo distributions where the locations of the zeros can be calculated by independent numerical methods. The results are presented in such a way that the methods can be applied for general lattice models. Applications to specific lattice models will be discussed in a separate publication.

We describe a formalism to calculate form factor and charge density distribution of the pion in the chiral limit using the holographic dual model of QCD with hard-wall cutoff. We introduce two conjugate pion wave functions and present analytic expressions for these functions and for the pion form factor. They allow us to relate such observables as the pion decay constant and the pion charge electric radius to the values of chiral condensate and hard-wall cutoff scale. The evolution of the pion form factor to large values of the momentum transfer is discussed, and results are compared to existing experimental data.

Recently Osland and Vereshagin noticed, based on sample calculations of some box diagrams, that in unpolarized $e^{+}{e}^{-}$ collisions $CP$-odd effects in the nondiagonal chargino-pair production process are generated at one loop. Here we perform a full one-loop analysis of these effects and point out that in some cases the neglected vertex and self-energy contributions may play a dominant role. We also show that $CP$ asymmetries in chargino production are sensitive not only to the phase of $\mu$ parameter in the chargino sector but also to the phase of stop trilinear coupling $A_t$.

Optical precision experiments are a powerful tool to explore hidden sectors of a variety of standard-model extensions with potentially tiny couplings to photons. An important example is given by extensions involving an extra light U(1) gauge degree of freedom, so-called paraphotons, with gauge-kinetic mixing with the normal photon. These models naturally give rise to minicharged particles which can be searched for with optical experiments. In this paper, we study the effects of paraphotons in such experiments. We describe in detail the role of a magnetic field for photon-paraphoton oscillations in models with low-mass minicharged particles. In particular, we find that the upcoming light-shining-through-walls experiments are sensitive to paraphotons and can distinguish them from axionlike particles.

We investigate models in minimal supergravity parameter space which contain metastable sleptons. We find the luminosity required to determine the slepton spin in these scenarios, and apply our analysis to two benchmark models. We show that the spin of the slepton in one of the benchmark models can be determined with less than $30{\mathrm{fb}}^{-1}$ of data, while the slepton spin in the other model can be determined with roughly $40{\mathrm{fb}}^{-1}$ of data. We show how our analysis can be applied to other models, and give an estimate of the luminosity needed for a spin determination as a function of the slepton mass. This analysis can be used to distinguish supersymmetry and extra dimensions.