In the conventional formulation of $N=1$ supersymmetry, a vector multiplet is supposed to be in the adjoint representation of a given gauge group. We present a new formulation with a vector multiplet in the nonadjoint representation of $\mathrm{SO}(N)$ gauge group. Our basic algebra is $[T^I,T^J]=f^{IJK}{T}^K$, $[T^I,U^i]=-(T^I{)}^{ij}{U}^j$, $[U^i,U^j]=-(T^I{)}^{ij}{T}^I$, where $T^I$ are the generators of $\mathrm{SO}(N)$, while $U^i$ are the new “generators” in certain nonadjoint real representation $R$ of $\mathrm{SO}(N)$. We use here the word generator in the broader sense of the word. Such a representation can be any real representation of $\mathrm{SO}(N)$ with the positive definite metric, satisfying $(T^I{)}^{ij}=-(T^I{)}^{ji}$ and $(T^I{)}^{[ij|}(T^I{)}^{|k]l}\equiv 0$. The first nontrivial examples are the spinorial ${\mathbf{8}}_{\mathrm{S}}$ and conjugate spinorial ${\mathbf{8}}_{\mathrm{C}}$ representations of SO(8) consistent with supersymmetry. We further couple the system to chiral multiplets and show that a Higgs mechanism can give positive definite $(\mathrm{\text{mass}}{)}^2$ to the new gauge fields for $U^i$. We show an analogous system working with $N=1$ supersymmetry in 10D, and thereby $N=4$ system in 4D interacting with extra multiplets in the representation $R$. We also perform superspace reformulation as an independent confirmation.

Coalescing binary black hole mergers are expected to be the strongest gravitational wave sources for ground-based interferometers, such as the LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Until recently it has been impossible to reliably derive the predictions of general relativity for the final merger stage, which takes place in the strong-field regime. Recent progress in numerical relativity simulations is, however, revolutionizing our understanding of these systems. We examine here the specific case of merging equal-mass Schwarzschild black holes in detail, presenting new simulations in which the black holes start in the late-inspiral stage on orbits with very low eccentricity and evolve for $\sim 1200M$ through $\sim 7$ orbits before merging. We study the accuracy and consistency of our simulations and the resulting gravitational waveforms, which encompass $\sim 14\mathrm{cycle}$ before merger, and highlight the importance of using frequency (rather than time) to set the physical reference when comparing models. Matching our results to post-Newtonian (PN) calculations for the earlier parts of the inspiral provides a combined waveform with less than one cycle of accumulated phase error through the entire coalescence. Using this waveform, we calculate signal-to-noise ratios (SNRs) for iLIGO, adLIGO, and LISA, highlighting the contributions from the late-inspiral and merger-ringdown parts of the waveform, which can now be simulated numerically. Contour plots of SNR as a function of $z$ and $M$ show that adLIGO can achieve $\mathrm{SNR}\gtrsim 10$ for some intermediate mass binary black holes (IMBBHs) out to $z\sim 1$, and that LISA can see massive binary black holes (MBBHs) in the range $3\times {10}^4\lesssim M/M_{\odot }\lesssim {10}^7$ at $\mathrm{SNR}>100$ out to the earliest epochs of structure formation at $z>15$.

We present the properties of a cosmic superstring network in the scenario of flux compactification. An infinite family of strings, the $(p,q)$ strings, are allowed to exist. The flux compactification leads to a string tension that is periodic in $p$. Monopoles, appearing here as beads on a string, are formed in certain interactions in such networks. This allows bare strings to become cosmic necklaces. We study network evolution in this scenario, outlining what conditions are necessary to reach a cosmologically viable scaling solution. We also analyze the physics of the beads on a cosmic necklace, and present general conditions for which they will be cosmologically safe, leaving the network’s scaling undisturbed. In particular, we find that a large average loop size is sufficient for the beads to be cosmologically safe. Finally, we argue that loop formation will promote a scaling solution for the interbead distance in some situations.

The equation of state for radiation is derived in a canonical formulation of the electromagnetic field. This allows one to include correction terms expected from canonical quantum gravity and to infer implications to the universe evolution in radiation dominated epochs. Corrections implied by quantum geometry can be interpreted in physically appealing ways, relating to the conformal invariance of the classical equations.

$J/\psi$ photoproduction is studied in the framework of the analytic $S$-matrix theory. The differential and integrated elastic cross sections for $J/\psi$ photoproduction are calculated from a dual amplitude with Mandelstam analyticity. It is argued that, at low energies, the background, which is the low-energy equivalent of the high-energy diffraction, replaces the Pomeron exchange. The onset of the high-energy Pomeron dominance is estimated from the fits to the data.

The minimal supersymmetric extension of the standard model with large $\tan \beta$ and heavy squarks ($M_{\tilde{q}}\gtrsim 1\mathrm{TeV}$) is a theoretically well-motivated and phenomenologically interesting extension of the standard model. This scenario naturally satisfies all the electroweak precision constraints and, in the case of not too heavy slepton sector ($M_{\tilde{\ell }}\lesssim 0.5\mathrm{TeV}$), can also easily accommodate the $(g-2{)}_{\mu }$ anomaly. Within this framework nonstandard effects could possibly be detected in the near future in a few low-energy flavor violating observables, such as $\mathcal{B}(B\to \tau \nu )$, $\mathcal{B}(B_{s,d}\to {\ell }^{+}{\ell }^{-})$, $\mathcal{B}(B\to X_s\gamma )$, and $\mathcal{B}(\mu \to e\gamma )$. Interpreting the $(g-2{)}_{\mu }$ anomaly as the first hint of this scenario, we analyze the correlations of these low-energy observables under the additional assumption that the relic density of a binolike lightest supersymmetric particle accommodates the observed dark-matter distribution.

If supersymmetry is discovered at the LHC, the measured spectrum of superpartner masses and couplings will allow us to probe the origins of supersymmetry breaking. However, to connect the collider-scale Lagrangian soft parameters to the more fundamental theory from which they arise, it is usually necessary to evolve them to higher scales. The apparent unification of gauge couplings restricts the possible forms of new physics above the electroweak scale, and suggests that such an extrapolation is possible. Even so, this task is complicated if the low-scale spectrum is not measured completely or precisely, or if there is new physics at heavy scales beyond the reach of collider experiments. In this work we study some of these obstacles to running up, and we investigate how to get around them. Our main conclusion is that even though such obstacles can make it very difficult to accurately determine the values of all the soft parameters at the high scale, there exist a number of special combinations of the soft parameters that can avoid these difficulties. We also present a systematic application of our techniques in an explicit example.

We recall how a new light gauge boson emerged in supersymmetric extensions of the standard model with an extra singlet chiral superfield, and how it could often behave very much as a light pseudoscalar, with the corresponding symmetry broken at a scale higher than electroweak. (I) The possible existence of such a new gauge boson $U$, light and very weakly coupled, allows for light dark matter particles, which could be at the origin of the 511 keV line from the galactic bulge. Could such a light gauge boson be found directly in $e^{+}{e}^{-}$ annihilations? Not so easily, in fact, due to various constraints limiting the size of its couplings, especially the axial ones, leading to an axionlike behavior or extra parity-violation effects. In particular, searches for the decay ${\rm Y}\to \gamma +\mathrm{\text{invisible}}U$ may be used to constrain severely the axial coupling of the $U$ to the electron, $f_{eA}=f_{bA}$, to be less than about ${10}^{-6}{m}_U(\mathrm{MeV})$, 50 times smaller than the $\simeq 5{10}^{-5}{m}_U(\mathrm{MeV})$ that could otherwise have been allowed from $g_e-2$. (II) The vector coupling of the $U$ to the electron may in principle be larger, but is also limited in size. Even under favorable circumstances (no axial couplings to quarks and charged leptons, and very small couplings to neutrinos), taking also into account possible $Z\mathrm{\text{−}}U$ mixing effects, we find from $g_{\mu }-2$, under reasonable assumptions (no cancellation effect, lepton universality), that the vector coupling of the $U$ to the electron can be at most as large as $\simeq 1.3{10}^{-3}$, for $m_U<m_{\mu }$. Such a coupling to the muon of the order of ${10}^{-3}$ could also be responsible for the somewhat large value of the measured $g_{\mu }-2$, as compared to standard model expectations, should this effect turn out to be real. (III) The $U$ couplings to electrons are otherwise likely to be smaller, e.g. $\lesssim 3{10}^{-6}{m}_U(\mathrm{MeV})$, if the couplings to neutrinos and electrons are similar. This restricts significantly the possibility of detecting a light $U$ boson in $e^{+}{e}^{-}\to \gamma U$, making this search quite challenging. Despite the smallness of these couplings, $U$ exchanges can provide annihilation cross sections of light dark matter (LDM) particles of the appropriate size, even if this may require that light dark matter be relatively strongly self-interacting.

We calculate an analogue of the average phase factor of the staggered fermion determinant at imaginary chemical potential. Our results from the lattice agree well with the analytical predictions in the microscopic regime for both quenched and phase-quenched QCD. We demonstrate that the average phase factor in the microscopic domain is dominated by the lowest-lying Dirac eigenvalues.

Zero-bin subtractions are required to avoid double counting soft contributions in collinear loop integrals in soft-collinear effective theory (SCET). In traditional approaches to factorization, double counting is avoided by dividing jet functions by matrix elements of soft Wilson lines. In this paper, we compare the two approaches to double counting, studying the quark form factor and deep inelastic scattering (DIS) as $x_B\to 1$ as examples. We explain how the zero-bin subtractions in SCET are required to reproduce the well-established factorization theorem for DIS as $x_B\to 1$. We study one-loop virtual contributions to the quark form factor and real gluon emission diagrams in DIS. The two approaches to double counting are equivalent if dimensional regularization (DR) is used to regulate infrared (IR) divergences. We discuss in detail ambiguities in the calculation of one-loop scaleless integrals in DR in SCET and perturbative QCD. We also demonstrate a nontrivial check of the equivalence of the zero-bin subtraction and the soft Wilson line subtraction in the virtual two-loop Abelian contributions to the quark form factor.

We present a comprehensive update of the bounds on $R$-parity violating supersymmetric couplings from lepton-flavor- and lepton-number-violating decay processes. We consider $\tau$ and $\mu$ decays as well as leptonic and semileptonic decays of mesons. We present several new bounds resulting from $\tau$, $\eta$, and kaon decays and correct some results in the literature concerning $B$ meson decays.

Effective field theory of Balitsky, Fadin, Kuraev, and Lipatov (BFKL) pomerons interacting by QCD triple pomeron vertices is investigated. Classical equations of motion for the effective pomeron fields are presented being a minimal extension of the Balitsky-Kovchegov equation that incorporates both merging and splitting of the pomerons and that is self-dual. The equations are solved for symmetric boundary conditions. The solutions provide the dominant contribution to the scattering amplitudes in the semiclassical approximation. We find that for rapidities of the scattering larger than a critical value $Y_c$ at least two classical solutions exist. Curiously, for each of the two classical solutions with the lowest action the symmetry between the projectile and the target is found to be spontaneously broken, being however preserved for the complete set of classical solutions. The solving configurations at rapidities $Y>Y_c$ consist of a Gribov field being strongly suppressed even at very large gluon momenta and the complementary Gribov field that converges at high $Y$ to a solution of the Balitsky-Kovchegov equation. Interpretation of the results is given and possible consequences are shortly discussed.

We show that hard-scattering factorization is violated in the production of high-$p_T$ hadrons in hadron-hadron collisions, in the case that the hadrons are back-to-back, so that $k_T$ factorization is to be used. The explicit counterexample that we construct is for the single-spin asymmetry with one beam transversely polarized. The Sivers function needed here has particular sensitivity to the Wilson lines in the parton densities. We use a greatly simplified model theory to make the breakdown of factorization easy to check explicitly. But the counterexample implies that standard arguments for factorization fail not just for the single-spin asymmetry but for the unpolarized cross section for back-to-back hadron production in QCD in hadron-hadron collisions. This is unlike corresponding cases in $e^{+}{e}^{-}$ annihilation, Drell-Yan, and deeply inelastic scattering. Moreover, the result endangers factorization for more general hadroproduction processes.

Results from a phenomenological analysis of $W$ and $Z$ hard diffractive hadroproduction at high energies are reported. Using the Regge factorization approach, we consider the recent diffractive parton density functions extracted by the H1 Collaboration at DESY-HERA. In addition, we take into account multiple Pomeron exchange corrections considering a gap survival probability factor. It is found that the ratio of diffractive to nondiffractive boson production is in good agreement with the CDF and D0 data. We make predictions which could be compared to future measurements at the LHC.

We present results of a search at CDF in $929\pm 56{\mathrm{pb}}^{-1}$ of $p\overline{p}$ collisions at 1.96 TeV for the anomalous production of events containing a high-transverse momentum charged lepton ($\ell$, either $e$ or $\mu$) and photon ($\gamma$), accompanied by missing transverse energy (${\mathrm{E̸}}_T$), and/or additional leptons and photons, and jets (X). We use the same selection criteria as in a previous CDF Run I search, but with an order-magnitude larger data set, a higher $p\overline{p}$ collision energy, and the CDF II detector. We find 163 $\ell \gamma {\mathrm{E̸}}_T+X$ events, compared to an expectation of $150.6\pm 13.0$ events. We observe 74 $\ell \ell \gamma +X$ events, compared to an expectation of $65.1\pm 7.7$ events. We find no events similar to the Run I $ee\gamma \gamma {\mathrm{E̸}}_T$ event.

One of the goals of the landscape program in string theory is to extract information about the space of string vacua in the form of statistical correlations between phenomenological features that are otherwise uncorrelated in field theory. Such correlations would thus represent predictions of string theory that hold independently of a vacuum-selection principle. In this paper, we study statistical correlations between two features which are likely to be central to any potential description of nature at high-energy scales: gauge symmetries and spacetime supersymmetry. We analyze correlations between these two kinds of symmetry within the context of perturbative heterotic string vacua, and find a number of striking features. We find, for example, that the degree of spacetime supersymmetry is strongly correlated with the probabilities of realizing certain gauge groups, with unbroken supersymmetry at the string scale tending to favor gauge-group factors with larger rank. We also find that nearly half of the heterotic landscape is nonsupersymmetric and yet tachyon-free at tree level; indeed, less than a quarter of the tree-level heterotic landscape exhibits any supersymmetry at all at the string scale.

We study the solution of the nonlinear Balitsky-Kovchegov evolution equation with the recently calculated running coupling corrections [I. I. Balitsky, Phys. Rev. D 75, 014001 (2007). and Y. Kovchegov and H. Weigert, Nucl. Phys. A784, 188 (2007).]. Performing a numerical solution we confirm the earlier result of Albacete et al. [Phys. Rev. D 71, 014003 (2005).] (obtained by exploring several possible scales for the running coupling) that the high energy evolution with the running coupling leads to a universal scaling behavior for the dipole-nucleus scattering amplitude, which is independent of the initial conditions. It is important to stress that the running coupling corrections calculated recently significantly change the shape of the scaling function as compared to the fixed coupling case, in particular, leading to a considerable increase in the anomalous dimension and to a slow-down of the evolution with rapidity. We then concentrate on elucidating the differences between the two recent calculations of the running coupling corrections. We explain that the difference is due to an extra contribution to the evolution kernel, referred to as the subtraction term, which arises when running coupling corrections are included. These subtraction terms were neglected in both recent calculations. We evaluate numerically the subtraction terms for both calculations, and demonstrate that when the subtraction terms are added back to the evolution kernels obtained in the two works the resulting dipole amplitudes agree with each other. We then use the complete running coupling kernel including the subtraction term to find the numerical solution of the resulting full nonlinear evolution equation with the running coupling corrections. Again the scaling regime is recovered at very large rapidity with the scaling function unaltered by the subtraction term.

We consider an exact Foldy-Wouthuysen transformation for the Dirac spinor field on the combined background of a gravitational wave and constant uniform magnetic field. By taking the classical limit of the spinor field Hamiltonian, we arrive at the equations of motion for the nonrelativistic spinning particle. Two different kinds of gravitational fields are considered and in both cases the effect of the gravitational wave on the spinor field and on the corresponding spinning particle may be enforced by a sufficiently strong magnetic field. This result can be relevant for astrophysical applications and, in principle, useful for creating the gravitational wave detectors based on atomic physics and precise interferometry.

We investigate the weak-field, post-Newtonian (PN) expansion to the solution of the field equations in Chern-Simons (CS) gravity with a perfect fluid source. In particular, we study the mapping of this solution to the parametrized post-Newtonian (PPN) formalism to 1 PN order in the metric. We find that the PPN parameters of Chern-Simons gravity are identical to those of general relativity, with the exception of the inclusion of a new term that is proportional to the Chern-Simons coupling parameter and the curl of the PPN vector potentials. We also find that the new term is naturally enhanced by the nonlinearity of spacetime and we provide a physical interpretation for it. By mapping this correction to the gravito-electromagnetic framework, we study the corrections that this new term introduces to the acceleration of point particles and the frame-dragging effect in gyroscopic precession. We find that the CS correction to these classical predictions could be used by current and future experiments to place bounds on intrinsic parameters of Chern-Simons gravity and, thus, string theory.

We consider the variation of the surface spanned by closed strings in a spacetime manifold. Using the Nambu-Goto string action, we induce the geodesic surface equation and the geodesic surface deviation equation which yields a Jacobi field, and we define the index form of a geodesic surface as in the case of point particles to discuss conjugate strings on the geodesic surface.