The extensions of the minimal supersymmetric model (MSSM), driving mainly from the need to solve the $\mu$ problem, involve novel matter species and gauge groups. These extended MSSM models can be searched for at the LHC via the effects of the gauge and Higgs bosons or their fermionic partners. Traditionally, the focus has been on the study of the extra forces induced by the new gauge and Higgs bosons present in such models. An alternative way of studying such effects is through the superpartners of matter species and the gauge forces. We thus consider a $U(1{)}^{\prime }$ gauge extension of the MSSM, and perform an extensive study of the signatures of the model through the production and decays of the scalar quarks and gluino, which are expected to be produced copiously at the LHC. After a detailed study of the distinctive features of such models with regard to the signatures at the LHC, we carry out a detailed Monte Carlo analysis of the signals from the process $pp\to n\mathrm{\text{leptons}}+m\mathrm{\text{jets}}+{\mathrm{E̸}}_T$, and compare the resulting distributions with those predicted by the MSSM. Our results show that the searches for the extra gauge interactions in the supersymmetric framework can proceed not only through the forces mediated by the gauge and Higgs bosons but also through the superpartner forces mediated by the gauge and Higgs fermions. Analysis of the events induced by the squark/gluino decays presented here is complementary to the direct $Z^{\prime }$ searches at the LHC.

The spectrum of baryons with two heavy quarks is predicted, assuming a configuration of a light quark and a heavy diquark. The masses are computed within a semirelativistic quark model, using a potential obtained in a gauge-gravity (anti-de Sitter/QCD) framework. All the parameters defining the model are determined fitting the meson spectrum. The obtained mass of ${\Xi }_{cc}$ is in agreement with the measurements.

We perform a study of the exclusive production of $D\overline{D}$, $D^{*}$$\overline{D}$, and $D^{*}{\overline{D}}^{*}$ in initial-state-radiation events, from $e^{+}{e}^{-}$ annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium and possible new resonances. The data sample corresponds to an integrated luminosity of $384{\mathrm{fb}}^{-1}$ and was recorded by the BABAR experiment at the PEP-II storage rings. The $D\overline{D}$, $D^{*}\overline{D}$, and $D^{*}{\overline{D}}^{*}$ mass spectra show clear evidence of several $\psi$ resonances. However, there is no evidence for $Y(4260)\to D^{*}\overline{D}$ or $Y(4260)\to D^{*}{\overline{D}}^{*}$.

In [J. Alexandre, K. Farakos, N. E. Mavromatos, and P. Pasipoularides, Phys. Rev. D 77, 105001 (2008).] we have studied decoherence models for flavor oscillations in four-dimensional stochastically-fluctuating space times and discussed briefly the sensitivity of current terrestrial and astrophysical neutrino experiments to such models. In this addendum we extend these results to incorporate the effects due to the expansion of the Universe, so that our analysis can be useful in studies of extragalactic high-energy neutrinos, such as those coming from gamma ray bursts at cosmological distances. Unfortunately for some microscopic models of foam, constructed in the string theory framework, we arrive at pessimistic conclusions about the detectability of the decoherence effects via flavor-oscillation measurements.

We report precise simulations of ${\varphi }^4$ theory in the Ising limit. A recent technique to stochastically evaluate the all-order strong coupling expansion is combined with exact identities in the closely related Aizenman random current representation. In this way estimates of the renormalized coupling close to the continuum limit become possible with unprecedented precision and yet low CPU cost. As a sample application we present results for the unbroken phase of the Ising model in dimensions 3, 4 and 5 and investigate the question of triviality by studying a finite size scaling continuum limit.

We study the effect of extra dimensions on the process of massive Dirac fermion emission in the spacetime of the ($4+n$)-dimensional black hole, by examining the Dirac operator in arbitrary spacetime dimension. We comment on both bulk and brane emissions and find the absorption cross section and luminosity of Hawking radiation in the low-energy approximation.

The constraints on departures from general relativity (GR) at cosmological length scales due to cosmic microwave background (CMB) data are discussed. The departure from GR is measured by the ratio, parametrized as $1+{\varpi }_0(1+z{)}^{-S}$, between the gravitational potentials conventionally appearing in the geodesic equation and the Poisson equation. Current CMB data indicate ${\varpi }_0={1.67}_{-1.87}^{+3.07}$ at the $2\sigma$ confidence level, while $S$ remains unconstrained. The departure from GR affects the lensing conversion of E-mode into B-mode polarization. Hence, the lensing measurements from CMBpol alone should be able to improve the constraint to ${\varpi }_0<0.52$ ($2\sigma$) for a fiducial ${\varpi }_0=0$ model independent of $S$.

Recently, there have been several evidences that the hadronic total cross section ${\sigma }_{\mathrm{tot}}$ is proportional to $B{log}^{2}s$, which is consistent with the Froissart unitarity bound. The COMPETE Collaboration has further assumed ${\sigma }_{\mathrm{tot}}\simeq B{log}^2(s/s_0)+Z$ to extend its universal rise with the common values of $B$ and $s_0$ for all hadronic scatterings to reduce the number of adjustable parameters. It was suggested that the coefficient $B$ was universal in the arguments of the color glass condensate of QCD in recent years. However, there has been no rigorous proof yet based only on QCD. We attempt to investigate the value of $B$ for ${\pi }^{\mp }p$, $K^{\mp }p$ and $\overline{p}p$, $pp$ scatterings, respectively, through the search for the simultaneous best fit to the experimental ${\sigma }_{\mathrm{tot}}$ and $\rho$ ratios at high energies. The ${\sigma }_{\mathrm{tot}}$ at the resonance- and intermediate-energy regions has also been exploited as a duality constraint based on the special form of the finite-energy sum rule. We estimate the values of $B$, $s_0$, and $Z$ individually for ${\pi }^{\mp }p$, $K^{\mp }p$ and $\overline{p}p$, $pp$ scatterings without using the universality hypothesis. It turns out that the values of $B$ are mutually consistent within 1 standard deviation. It has to be stressed that we cannot obtain such a definite conclusion without the duality constraint. It is also interesting to note that the values of $Z$ for $\pi p$, $Kp$, and $\overline{p}(p)p$ approximately satisfy the ratio $2:2:3$ predicted by the quark model. The obtained value of $B$ for $\overline{p}(p)p$ is $B_{pp}=0.280\pm 0.015\mathrm{mb}$, which predicts ${\sigma }_{\mathrm{tot}}^{pp}=108.0\pm 1.9\mathrm{mb}$ and ${\rho }^{pp}=0.131\pm 0.0025$ at the LHC energy $\sqrt{s}=14\mathrm{TeV}$.

To illuminate how electroweak symmetry breaking shapes the physical world, we investigate toy models in which no Higgs fields or other constructs are introduced to induce spontaneous symmetry breaking. Two models incorporate the standard $\mathrm{SU}(3{)}_{\mathrm{c}}\otimes \mathrm{SU}(2{)}_{\mathrm{L}}\otimes \mathrm{U}(1{)}_Y$ gauge symmetry and fermion content similar to that of the standard model. The first class—like the standard electroweak theory—contains no bare mass terms, so the spontaneous breaking of chiral symmetry within quantum chromodynamics is the only source of electroweak symmetry breaking. The second class adds bare fermion masses sufficiently small that QCD remains the dominant source of electroweak symmetry breaking and the model can serve as a well-behaved low-energy effective field theory to energies somewhat above the hadronic scale. A third class of models is based on the left-right-symmetric $\mathrm{SU}(3{)}_{\mathrm{c}}\otimes \mathrm{SU}(2{)}_{\mathrm{L}}\otimes \mathrm{SU}(2{)}_{\mathrm{R}}\otimes \mathrm{U}(1)$ gauge group. In a fourth class of models, built on $\mathrm{SU}(4{)}_{\mathrm{PS}}\otimes \mathrm{SU}(2{)}_{\mathrm{L}}\otimes \mathrm{SU}(2{)}_{\mathrm{R}}$ gauge symmetry, the lepton number is treated as a fourth color and the color gauge group is enlarged to the $\mathrm{SU}(4{)}_{\mathrm{PS}}$ of Pati and Salam (PS). Many interesting characteristics of the models stem from the fact that the effective strength of the weak interactions is much closer to that of the residual strong interactions than in the real world. The Higgs-free models not only provide informative contrasts to the real world, but also lead us to consider intriguing issues in the application of field theory to the real world.

We have performed new big bang nucleosynthesis calculations, which employ arbitrarily specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these distributions to the thermodynamics, the expansion rate, and scale factor-time/temperature relationship, as well as to all relevant weak, electromagnetic, and strong nuclear reaction processes in the early Universe. With this approach, we can treat any scenario in which neutrino or antineutrino spectral distortion might arise. These scenarios might include, for example, decaying particles, active-sterile neutrino oscillations, and active-active neutrino oscillations in the presence of significant lepton numbers. Our calculations allow lepton numbers and sterile neutrinos to be constrained with observationally determined primordial helium and deuterium abundances. We have modified a standard big bang nucleosynthesis code to perform these calculations and have made it available to the community.

Alternative theories of gravity predict the presence of massive scalar, vector, and tensor gravitational wave modes in addition to the standard massless spin 2 graviton of general relativity. The deflection and frequency shift effects on light from distant sources propagating through a stochastic background of gravitational waves, containing such modes, differ from their counterparts in general relativity. Such effects are considered as a possible signature for alternative gravity in attempts to detect deviations from Einstein’s gravity by astrophysical means.

We model the nonlinear saturation of the $r$-mode instability via three-mode couplings and the effects of the instability on the spin evolution of young neutron stars. We include one mode triplet consisting of the $r$-mode and two near-resonant inertial modes that couple to it. We find that the spectrum of evolutions is more diverse than previously thought. We start our evolutions with a star of temperature $\sim {10}^{10}\mathrm{K}$ and a spin frequency close to the Kepler break-up frequency. We assume that hyperon bulk viscosity dominates at high temperatures ($T\sim {10}^9–{10}^{10}\mathrm{K}$) and boundary layer viscosity dominates at lower temperatures ($\sim \mathrm{\text{a few}}\times {10}^8\mathrm{K}$). To explore possible nonlinear behavior, we vary properties of the star such as the hyperon superfluid transition temperature, the strength of the boundary layer viscosity, and the fraction of the star that cools via direct URCA reactions. The evolution of the star is dynamic and initially dominated by fast neutrino cooling. Nonlinear effects become important when the $r$-mode amplitude grows above its first parametric instability threshold. The balance between neutrino cooling and viscous heating plays an important role in the evolution. Depending on the initial $r$-mode amplitude, and on the strength of the viscosity and of the cooling this balance can occur at different temperatures. If thermal equilibrium occurs on the $r$-mode stability curve, where gravitational driving equals viscous damping, the evolution may be adequately described by a one-mode model. Otherwise, nonlinear effects are important and lead to various more complicated scenarios. Once thermal balance occurs, the star spins down oscillating between thermal equilibrium states until the instability is no longer active. The average evolution of the mode amplitudes can be approximated by quasistationary states that are determined algebraically. For lower viscosity we observe runaway behavior in which the $r$-mode amplitude passes several parametric instability thresholds. In this case more modes need to be included to model the evolution accurately. In the most optimistic case, we find that gravitational radiation from the $r$-mode instability in a very young, fast spinning neutron star within about 1 Mpc of Earth may be detectable by advanced LIGO for years, and perhaps decades, after formation. Details regarding the amplitude and duration of the emission depend on the internal dissipation of the modes of the star, which would be probed by such detections.

We study the Gregory-Laflamme instability of 5D compactified, electrically charged black strings. We consider static, linear perturbations of these solutions and derive a master equation for these perturbations. Using numerical analysis we search for the threshold unstable modes and derive the critical wavelength. The results are illustrated in the black string mass vs electric charge phase diagram. A similar diagram is constructed using the global thermodynamic equilibrium argument applied to the charged string and 5D electrically charged black hole. The results derived illustrate that an electric charge makes the black string less stable.

A theorem related to the Newman-Penrose constants is proven. The theorem states that all the Newman-Penrose constants of asymptotically flat, stationary, asymptotically algebraically special electrovacuum space-times are zero. Straightforward application of this theorem shows that all the Newman-Penrose constants of the Kerr-Newman space-time must vanish.

The phase-integral approximation devised by Fröman and Fröman is used for computing cosmological perturbations in the quadratic chaotic inflationary model. The phase-integral formulas for the scalar and tensor power spectra are explicitly obtained up to fifth order of the phase-integral approximation. We show that the phase integral gives a very good approximation for the shape of the power spectra associated with scalar and tensor perturbations as well as the spectral indices. We find that the accuracy of the phase-integral approximation compares favorably with the numerical results and those obtained using the slow-roll and uniform-approximation methods.

The spectrum of the gravitational wave background originating from quantum fluctuations during inflation is calculated numerically for various inflation models over a wide range of frequencies. We take into account four ingredients: the scalar field dynamics during inflation making no use of the slow-roll approximation, the fermionic decay of the scalar field with a small coupling constant during the reheating process, the change of the effective number of degrees of freedom $g_{*}$ in the radiation-dominated era, and the anisotropic stress of free-streaming neutrinos. By numerically solving the evolution of gravitational waves during and after inflation up to the present, all of these effects can be examined comprehensively and accurately over a broad spectrum, even at very high frequencies. We find that the spectrum shows (i) a large deviation from the spectrum less accurate obtained by Taylor expanding around the CMB scale using the slow-roll approximation, (ii) a characteristic frequency dependence due to the reheating effect, and (iii) damping due to the $g_{*}$ changes and the neutrino anisotropic stress. We suggest that future analysis of the gravitational wave background should take into consideration the fact that analytical estimates using the Taylor expansion overestimate the amplitude of the spectrum.

We investigate the high-energy neutrino emission expected from newly born magnetars surrounded by their stellar ejecta. Protons might be accelerated up to 0.1–100 EeV energies possibly by, e.g., the wave dissipation in the winds, leading to hadronic interactions in the stellar ejecta. The resulting PeV-EeV neutrinos can be detected by IceCube/KM3Net with a typical peak time scale of a few days after the birth of magnetars, making the characteristic soft-hard-soft behavior. Detections would be important as a clue to the formation mechanism of magnetars, although there are ambiguities coming from uncertainties of several parameters such as velocity of the ejecta. Nondetections would also lead to useful constraints on the scenario.

Data collected at the Pierre Auger Observatory are used to establish an upper limit on the diffuse flux of tau neutrinos in the cosmic radiation. Earth-skimming ${\nu }_{\tau }$ may interact in the Earth’s crust and produce a $\tau$ lepton by means of charged-current interactions. The $\tau$ lepton may emerge from the Earth and decay in the atmosphere to produce a nearly horizontal shower with a typical signature, a persistent electromagnetic component even at very large atmospheric depths. The search procedure to select events induced by $\tau$ decays against the background of normal showers induced by cosmic rays is described. The method used to compute the exposure for a detector continuously growing with time is detailed. Systematic uncertainties in the exposure from the detector, the analysis, and the involved physics are discussed. No $\tau$ neutrino candidates have been found. For neutrinos in the energy range $2\times {10}^{17}\mathrm{eV}<E_{\nu }<2\times {10}^{19}\mathrm{eV}$, assuming a diffuse spectrum of the form $E_{\nu }^{-2}$, data collected between 1 January 2004 and 30 April 2008 yield a 90% confidence-level upper limit of $E_{\nu }^{2}d{N}_{{\nu }_{\tau }}/d{E}_{\nu }<9\times {10}^{-8}\mathrm{GeV}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}{\mathrm{sr}}^{-1}$.

We test the reliability of the Polyakov-loop extended Nambu–Jona-Lasinio (PNJL) model, comparing the model result with the lattice data at nonzero imaginary chemical potential. The PNJL model with the vector-type four-quark and scalar-type eight-quark interactions reproduces the lattice data on the pseudocritical temperatures of the deconfinement and chiral phase transitions. The QCD phase diagram in the real chemical potential region is predicted by the PNJL model. The critical end point survives, even if the vector-type four-quark interaction is taken into account.

Recently, realistic lattice QCD calculations with $2+1$ flavors of domain wall fermions and the Iwasaki gauge action have been performed by the RBC and UKQCD Collaborations. Here, results for the bottomonium spectrum computed on their gauge configurations of size ${24}^3\times 64$ with a lattice spacing of approximately 0.11 fm and four different values for the light quark mass are presented. Improved lattice nonrelativistic QCD is used to treat the $b$ quarks inside the bottomonium. The results for the radial and orbital energy splittings are found to be in good agreement with experimental measurements, indicating that systematic errors are small. The calculation of the ${\rm Y}(2S)-{\rm Y}(1S)$ energy splitting provides an independent determination of the lattice spacing. For the most physical ensemble it is found to be $a^{-1}=1.740(25)(19)\mathrm{GeV}$, where the first error is statistical/fitting and the second error is an estimate of the systematic errors due to the lattice nonrelativistic QCD action.