We report on the results of a Markov chain Monte Carlo analysis of an inverse power law (IPL) quintessence model using the Dark Energy Task Force (DETF) simulated data sets as a representation of future dark energy experiments. We generate simulated data sets for a $\Lambda \mathrm{CDM}$ background cosmology as well as a case where the dark energy is provided by a specific IPL fiducial model, and present our results in the form of likelihood contours generated by these two background cosmologies. We find that the relative constraining power of the various DETF data sets on the IPL model parameters is broadly equivalent to the DETF results for the $w_0-w_a$ parametrization of dark energy. Finally, we gauge the power of DETF “stage 4” data by demonstrating a specific IPL model which, if realized in the universe, would allow stage 4 data to exclude a cosmological constant at better than the $3\sigma$ level.

Higher dimensional nonrenormalizable operators may modify the standard model Higgs potential in many interesting ways. Here, we consider the appearance of a second vacuum which may play an important role in cosmology. For a certain range of parameters, the usual second-order electroweak phase transition is followed by a first-order phase transition that may drive the late time accelerated expansion of the Universe. Such a potential contains kinklike solutions which in turn can play a crucial role in reconstructing the global shape of the potential in colliders, as we explicitly demonstrate.

The standard cosmological model is assumed to respect parity symmetry. Under this assumption the cross correlations of the cosmic microwave background’s temperature anisotropy and “gradient”-like polarization, with the “curl”-like polarization, identically vanish over the full sky. However, extensions of the standard model which allow for light scalar field or axion coupling to the electromagnetic field, or coupling to the Riemann gravitational field strength, as well as other modifications of field theories, may induce a rotation of the cosmic microwave background polarization plane on cosmological scales and manifest itself as nonvanishing $TB$ and $EB$ cross correlations. Recently, the degree of parity violation (reflected in polarization rotation) was constrained using data from BOOMERANG, WMAP, and QUAD. Forecasts have been made for near-future experiments (e.g. PLANCK) to further constrain parity- and Lorentz-violating terms in the fundamental interactions of nature. Here we consider a real-world effect induced by a class of telescope beam systematics which can mimic the rotation of polarization plane or otherwise induce nonvanishing $TB$ and $EB$ correlations. In particular, adopting the viewpoint that the primary target of future experiments will be the inflationary $B$-mode signal, we assume the beam systematics of the upcoming PLANCK and POLARBEAR experiments are optimized towards this goal, and explore the implications of the allowed levels of beam systematics on the resulting precision of polarization-rotation measurements.

Concepts developed in the gravitational lensing techniques such as shear, convergence, tangential, and radial arcs maybe used to see how tenable inhomogeneous models proposed to explain the acceleration of the universe models are. We study the widely discussed Lemaitre-Tolman-Bondi (LTB) cosmological models. It turns out that for the observer sitting at origin of a global LTB solution the shear vanishes as in the Friedmann-Robertson-Walker models, while the value of convergence is different, which may lead to observable cosmological effects. We also consider Swiss-cheese models proposed recently based on LTB with an observer sitting in the Friedmann-Robertson-Walker part. It turns out that they have different behavior as far as the formation of radial and tangential arcs are concerned.

We study the effects of $CP$ violation in the associated production of a charged Higgs boson and a top quark at the LHC, $pp\to t{H}^{\pm }+X$. We calculate the $CP$ violating asymmetry between the total cross section for $H^{+}$ and $H^{-}$ production at next-to-leading order in the minimal supersymmetric standard model (MSSM), and perform a detailed numerical analysis. In the production, the asymmetry is of the order of 20%. The asymmetry in the production and any subsequent decay of an on shell charged Higgs boson is to a good approximation the sum of the asymmetry in the production and the asymmetry in the decay. We consider subsequent decays of $H^{\pm }$ to $tb$, ${\nu }_{\tau }{\tau }^{\pm }$ and $W{h}^0$. In the case with $H^{\pm }\to tb$ decay, mainly due to $CP$ violating box graphs with gluino, the asymmetry can go up to $\sim 12\%$.

We introduce particle phenomenology on the noncommutative spacetime called the Groenewold-Moyal plane. The length scale of spacetime noncommutativity is constrained from the $CPT$ violation measurements in the $K^0-{\overline{K}}^0$ system and $g-2$ difference of ${\mu }^{+}-{\mu }^{-}$. The $K^0-{\overline{K}}^0$ system provides an upper bound on the length scale of spacetime noncommutativity of the order of ${10}^{-32}\mathrm{m}$, corresponding to a lower energy bound $E$ of the order of $E\gtrsim {10}^{16}\mathrm{GeV}$. The $g-2$ difference of ${\mu }^{+}-{\mu }^{-}$ constrains the noncommutativity length scale to be of the order of ${10}^{-20}\mathrm{m}$, corresponding to a lower energy bound $E$ of the order of $E\gtrsim {10}^3\mathrm{GeV}$. We also present the phenomenology of the electromagnetic interaction of electrons and nucleons at the tree level on the noncommutative spacetime. We show that the distributions of charge and magnetization of nucleons are affected by spacetime noncommutativity. The analytic properties of electromagnetic form factors are also changed and it may give rise to interesting experimental signals.

We undertake a phenomenological study of the extra neutral $Z^{\prime }$ boson in the minimal quiver standard model and discuss limits on the model’s parameters from previous precision electroweak experiments, as well as detection prospects at the Large Hadron Collider at CERN. We find that masses lower than around 700 GeV are excluded by the $Z$-pole data from the CERN LEP collider, and below 620 GeV by experimental data from di-electron events at the Fermilab Tevatron collider. We also find that at a mass of 1 TeV the LHC cross section would show a small peak in the di-lepton and top pair channel.

Group theoretical factors from grand unified theory (GUT) symmetry breaking can lead to predictions for the ratios of quark and lepton masses (or Yukawa couplings) at the unification scale. Because of supersymmetric (SUSY) threshold corrections the viability of such predictions can depend strongly on the SUSY parameters. For three common minimal SUSY breaking scenarios with anomaly, gauge, and gravity mediation we investigate which GUT scale ratios $m_e/m_d$, $m_{\mu }/m_s$, $y_{\tau }/y_b$, and $y_t/y_b$ are allowed when phenomenological constraints from electroweak precision observables, $B$ physics, $(g-2{)}_{\mu }$, mass limits on sparticles from direct searches as well as, optionally, dark matter constraints are taken into account. We derive possible new predictions for the GUT scale mass ratios and compare them with the phenomenologically allowed ranges. We find that new GUT scale predictions such as $m_{\mu }/m_s=9/2$ or 6 and $y_{\tau }/y_b=3/2$ or 2 are often favored compared to the ubiquitous relations $m_{\mu }/m_s=3$ or $y_{\tau }/y_b=1$. They are viable for characteristic SUSY scenarios, testable at the CERN LHC and future colliders.

We investigate pion superfluidity in the frame of a two flavor Nambu–Jona-Lasinio model beyond mean field approximation. We calculate the thermodynamics to the next to leading order in an expansion in the inverse number of colors, including both quark and meson contributions at finite temperature and baryon and isospin density. Because of the meson fluctuations, the Sarma phase which exists at the mean field level is washed away, and the Bose-Einstein condensation region at low isospin density is highly suppressed.

We study $CP$ violation and the contribution of the strong kaon-pion interactions in the three-body $B\to K{\pi }^{+}{\pi }^{-}$ decays. We extend our recent work on the effect of the two-pion $S$- and $P$-wave interactions to that of the corresponding kaon-pion ones. The weak amplitudes have a first term derived in QCD factorization and a second one as a phenomenological contribution added to the QCD penguin amplitudes. The effective QCD coefficients include the leading order contributions plus next-to-leading order vertex and penguins corrections. The matrix elements of the transition to the vacuum of the kaon-pion pairs, appearing naturally in the factorization formulation, are described by the strange $K\pi$ scalar ($S$-wave) and vector ($P$-wave) form factors. These are determined from Muskhelishvili-Omnès coupled channel equations using experimental kaon-pion $T$-matrix elements, together with chiral symmetry and asymptotic QCD constraints. From the scalar form factor study, the modulus of the $K_0^{*}(1430)$ decay constant is found to be $(32\pm 5)\mathrm{MeV}$. The additional phenomenological amplitudes are fitted to reproduce the $K\pi$ effective mass and helicity angle distributions, the $B\to K^{*}(892)\pi$ branching ratios and the $CP$ asymmetries of the recent data from Belle and BABAR collaborations. We use also the new measurement by the BABAR group of the phase difference between the $B^0$ and ${\overline{B}}^0$ decay amplitudes to $K^{*}(892)\pi$. Our predicted $B^{\pm }\to K_0^{*}(1430){\pi }^{\pm }$, $K_0^{*}(1430)\to K^{\pm }{\pi }^{\mp }$ branching fraction, equal to $(11.6\pm 0.6)\times {10}^{-6}$, is smaller than the result of the analyzes of both collaborations. For the neutral $B^0$ decays, the predicted value is $(11.1\pm 0.5)\times {10}^{-6}$. In order to reduce the large systematic uncertainties in the experimental determination of the $B\to K_0^{*}(1430)\pi$ branching fractions, a new parametrization is proposed. It is based on the $K\pi$ scalar form factor, well constrained by theory and experiments other than those of $B$ decays.

We incorporate the color-screening effect due to light quark pair creation into the heavy quark-antiquark potential, and investigate the effects of screened potential on the spectrum of higher charmonium. We calculate the masses, electromagnetic decays, and E1 transitions of charmonium states in the screened potential model, and propose possible assignments for the newly discovered charmonium or charmoniumlike “$X$, $Y$, $Z$” states. We find the masses of higher charmonia with screened potential are considerably lower than those with unscreened potential. The ${\chi }_{c2}(2P)$ mass agrees well with that of the $Z(3930)$, and the mass of $\psi (4415)$ is compatible with $\psi (5S)$ rather than $\psi (4S)$. In particular, the discovered four $Y$ states in the initial state radiation process, i.e., $Y(4008)$, $Y(4260)$, $Y(4320/4360)$, $Y(4660)$ may be assigned as the $\psi (3S)$, $\psi (4S)$, $\psi (3D)$, $\psi (6S)$ states, respectively. The $X(3940)$ and $X(4160)$ found in the double charmonium production in $e^{+}{e}^{-}$ annihilation may be assigned as the ${\eta }_c(3S)$ and ${\chi }_{c0}(3P)$ states. Based on the calculated E1 transition widths for ${\chi }_{c1}(2P)\to \gamma J/\psi$ and ${\chi }_{c1}(2P)\to \gamma \psi (2S)$ and other results, we argue that the $X(3872)$ may be a ${\chi }_{c1}(2P)$ dominated charmonium state with some admixture of the $D^0{\overline{D}}^{*0}$ component. Possible problems encountered in these assignments and comparisons with other interpretations for these $X$, $Y$, $Z$ states are discussed in detail. We emphasize that more theoretical and experimental investigations are urgently needed to clarify these assignments and other interpretations.

We calculate ${\alpha }^2{\alpha }_s^2$ order QED contribution to $J/\psi$ production in the $pp(\overline{p})\to J/\psi +c\overline{c}$ color-singlet process at the Tevatron and LHC in the framework of nonrelativistic QCD. The contribution of the interference between the ${\alpha }^2{\alpha }_s^2$ QED and ${\alpha }_s^4$ QCD is also taken into account. The $J/\psi$ production associated with a charm-quark pair could be a measurable signal at hadron collider experiment. Our calculations show that by including the QED contribution, the $p_t$ distribution is enhanced by a factor of 1.5 (1.9) at the Tevatron (LHC) at $p_t=50(100)\mathrm{GeV}$. In addition, the polarization of $J/\psi$ turns from unpolarized in all regions to increasingly transverse when $p_t$ becomes larger.

We calculate rates of flavor exchange within clouds of neutrinos interacting with each other through the standard model coupling, assuming a conventional mass matrix. For cases in which there is an angular dependence in the relation among intensity, flavor, and spectrum, we find instabilities in the evolution equations and greatly speeded-up flavor exchange. The instabilities are categorized by examining linear perturbations to simple solutions, and their effects are exhibited in complete numerical solutions to the system. The application is to the region just under the neutrino surfaces in the supernova core.

The Penrose inequality has so far been proven in cases of spherical symmetry and in cases of zero extrinsic curvature. The next simplest case worth exploring would be nonspherical, nonrotating black holes with nonzero extrinsic curvature. Following Karkowski et al.’s construction of prolate black holes, we define initial data on an asymptotically flat spacelike 3-surface with nonzero extrinsic curvature that may be chosen freely. This gives us the freedom to define the location of the apparent horizon such that the Penrose inequality is violated. We show that the dominant energy condition is violated at the poles for all cases considered.

We show that Gordon’s optical metric on a curved spacetime can be generalized to include absorption by allowing the metric to become complex. We demonstrate its use in the realm of geometrical optics by giving three simple examples. We use one of these examples to compute corrected distance-redshift relations for Friedman-Lemaître-Robertson-Walker models in which the cosmic fluid has an associated complex index of refraction that represents grey extinction. We then fit this corrected Hubble curve to the type Ia supernovae data and provide a possible explanation (other than dark energy) of the deviation of these observations from dark matter predictions.

We consider corrections to the Einstein-Hilbert action, which contain both higher order and nonlocal terms. We derive an effective Newtonian gravitational constant applicable at the weak field limit and use the primordial nucleosynthesis (BBN) bound and the local gravity constraints on $G_{\mathrm{eff}}$ in order to test the viability of several cases of our general Lagrangian. We will also provide a BBN constrain on the $\square R$ gravitational correction.

We propose a simple dark energy model with the following properties: the model predicts a late-time dark radiation component that is not ruled out by current observational data, but which produces a distinctive time-dependent equation of state $w(z)$ for $z<3$. The dark energy field can be coupled strongly enough to standard model particles to be detected in colliders, and the model requires only modest additional particle content and little or no fine-tuning other than a new energy scale of order milli-electron volts.

We study the effects of including one-loop radiative corrections in a nonsupersymmetric hybrid inflationary model. These corrections can arise from Yukawa couplings between the inflaton and right-handed neutrinos, and induce a maximum in the potential which admits hilltop-type solutions in addition to the standard hybrid solutions. We obtain a red-tilted spectral index $n_s$, consistent with Wilkinson Microwave Anisotropy Probe 5 yr analysis data, for sub-Planckian values of the field. This is in contrast to the tree level hybrid analysis, in which a red-tilted spectrum is achieved only for trans-Planckian values of the field. Successful reheating is obtained at the end of the inflationary phase via a conversion of the inflaton and waterfall fields into right-handed neutrinos, whose subsequent decay can explain the observed baryon asymmetry via leptogenesis.

We propose a simple gauge extension of the minimal supersymmetric standard model, where the fine-tuning in the Higgs mass parameters is highly reduced. The Higgs boson is insensitive to high energies because of supersymmetry and also because it is a pseudo-Goldstone boson of a global symmetry (referred to as “double protection” or “super-little Higgs” mechanism). A large shift in the Higgs quartic self-coupling is obtained via a nondecoupling $D$ term coming from an extra gauge group, resulting in a Higgs that can be as heavy as 135 GeV with a tuning milder than 10%. With an appropriate choice of quantum numbers one can achieve that the additional quartic is generated without a corresponding shift in the Higgs mass, thus preserving the double protection of the Higgs. The model predicts the existence of several top-partner fermions one of which can be as light as 700 GeV, while the ordinary minimal supersymmetric standard model states could be as light as 400 GeV. In addition to many new particles in the multi-TeV range there would also be an axionlike state very weakly coupled to standard model matter, which could be in the sub-GeV regime, and sterile neutrinos, which could be light.

We consider models with multiple Higgs scalar gauge singlets and the resulting restrictions on the parameters from precision electroweak measurements. In these models, the scalar singlets mix with the $SU(2{)}_L$ Higgs doublet, potentially leading to reduced couplings of the scalars to fermions and gauge bosons relative to the standard model Higgs boson couplings. Such models can make the Higgs sector difficult to explore at the LHC. We emphasize the new physics resulting from the addition of at least two scalar Higgs singlets.