Maxima of the linear density field form a point process that can be used to understand the spatial distribution of virialized halos that collapsed from initially overdense regions. However, owing to the peak constraint, clustering statistics of discrete density peaks are difficult to evaluate. For this reason, local bias schemes have received considerably more attention in the literature thus far. In this paper, we show that the two-point correlation function of maxima of a homogeneous and isotropic Gaussian random field can be thought of, up to second order at least, as arising from a local bias expansion formulated in terms of rotationally invariant variables. This expansion relies on a unique smoothing scale, which is the Lagrangian radius of dark matter halos. The great advantage of this local bias approach is that it circumvents the difficult computation of joint probability distributions. We demonstrate that the bias factors associated with these rotational invariants can be computed using a peak-background split argument, in which the background perturbation shifts the corresponding probability distribution functions. Consequently, the bias factors are orthogonal polynomials averaged over those spatial locations that satisfy the peak constraint. In particular, asphericity in the peak profile contributes to the clustering at quadratic and higher order, with bias factors given by generalized Laguerre polynomials. We speculate that our approach remains valid at all orders, and that it can be extended to describe clustering statistics of any point process of a Gaussian random field. Our results will be very useful to model the clustering of discrete tracers with more realistic collapse prescriptions involving the tidal shear for instance.

In this paper, we continue to study a unified dark fluid model with a constant adiabatic sound speed but with the entropic perturbations. When the entropic perturbations are included, an effective sound speed, which reduces to the adiabatic sound speed when the entropic perturbations are zero, has to be specified as an additional free model parameter. Because of the relations between the adiabatic sound speed and equations of state $c_{s,ad}^2(a)=w(a)-d\ln (1+w(a))/3d\ln a$, the equation of state can be determined up to an integration constant, in principle, when an adiabatic sound speed is given. Then there are two degrees of freedom to describe the linear perturbations for a fluid. Its microscale properties are characterized by its equations of state or adiabatic sound speed and an effective sound speed. We take the effective sound speed and adiabatic sound speed as free model parameters and then use the currently available cosmic observational data sets, which include type Ia supernova Union 2.1, baryon acoustic oscillation, and WMAP 7-yr data of cosmic background radiation, to constrain the possible entropic perturbations and the adiabatic sound speed via the Markov Chain Monte Carlo method. The results show that the cosmic observations favor a small effective sound speed $c_{s,\mathrm{eff}}^2={0.00155}_{-0.00155}^{+0.000319}$ in the $1\sigma$ region.

By incorporating the curvature ${\Omega }_k$ as a free parameter, it has been found that the tension between the high redshift cosmic microwave background (CMB) shift parameter $R(z^{*})$ data and the low redshift Type Ia supernova (SNIa) and baryonic acoustic oscillation (BAO) data from the combination of Sloan Digital Sky Survey (SDSS) and Two-Degree Field Galaxy Redshift Survey (2dFGRS) can be ameliorated, and both $\mathrm{SNIa}+\mathrm{BAO}$ and $\mathrm{SNIa}+\mathrm{BAO}+\mathrm{CMB}$ favor that the decelerating parameter $q(z)$ shows a rapid variation in the sign at the small redshift. In this paper, with the Monte Carlo Markov chain method, we re-examine the evolutionary behavior of $q(z)$ using the latest observational data including the Union2 SNIa, BAO, and CMB data ($R(z^{*})$, $l_A(z^{*})$, $z^{*}$) from Wilkinson Microwave Anisotropy Probe 7-yr (WMAP7). For the BAO data, four different data sets obtained from the Two-Degree Field Galaxy Survey, the combination of SDSS and 2dFGRS, the WiggleZ Dark Energy Survey, and the Baryonic Oscillation Spectroscopic Survey, are used. Except for the spatially flat case constrained by $\mathrm{SNIa}+\mathrm{\text{the WiggleZ}}\mathrm{BAO}$ data, both SNIa and other $\mathrm{BAO}+\mathrm{SNIa}$ favor that the present cosmic acceleration is slowing down irrespective of whether the spatial curvature is included or not. However, once the WMAP7 CMB data is included, observations favor strongly the Lambda cold dark matter model, a spatially flat universe, and a speeding-up of the cosmic acceleration. Therefore, the inclusion of spatial curvature seems to have no effect on alleviating the tension between $\mathrm{SNIa}+\mathrm{BAO}$ and CMB in clear contrast to the previous work in the literature.

We study the standard model Higgs field as a source for the primordial curvature perturbation, particularly in the curvaton and modulated reheating scenario. We conclude that the Higgs cannot play as a curvaton due to the small energy density when it decays, however the modulated reheating by Higgs can be a viable scenario. In the latter case, the non-Gaussianity is inevitably generated and strongly constrains the type of potential of inflaton field and the Higgs-dependent interaction term. For the quadratic potential of the inflaton field with decay rate which nonlinearly depends on the Higgs vacuum expectation value, the contribution of the Higgs field to the primordial curvature perturbation must be less than 8%.

While standard solar model (SSM) predictions depend on approximately 20 input parameters, SSM neutrino flux predictions are strongly correlated with a single model output parameter, the core temperature $T_c$. Consequently, one can extract physics from solar neutrino flux measurements while minimizing the consequences of SSM uncertainties, by studying flux ratios with appropriate power-law weightings tuned to cancel this $T_c$ dependence. We reexamine an idea for constraining the primordial $\mathrm{C}+\mathrm{N}$ content of the solar core from a ratio of CN-cycle ${}^{15}\mathrm{O}$ to pp-chain ${}^8\mathrm{B}$ neutrino fluxes, showing that non-nuclear SSM uncertainties in the ratio are small and effectively governed by a single parameter, the diffusion coefficient. We point out that measurements of both CN-I cycle neutrino branches—${}^{15}\mathrm{O}$ and ${}^{13}\mathrm{N}$ $\beta$-decay—could, in principle, lead to separate determinations of the core C and N abundances, due to out-of-equilibrium CN-cycle burning in the cooler outer layers of the solar core. Finally, we show that the strategy of constructing “minimum uncertainty” neutrino flux ratios can also test other properties of the SSM. In particular, we demonstrate that a weighted ratio of ${}^7\mathrm{Be}$ and ${}^8\mathrm{B}$ fluxes constrains a product of S-factors to the same precision currently possible with laboratory data.

In this work, we study the constraints on the scenario of light stops and sbottoms in the next-to-minimal supersymmetric standard model (NMSSM), especially by a 125 GeV Higgs boson discovery and the LHC bounds on supersymmetry. The constraints from dark matter detections are also taken into account. From the parameter scan, we find that the NMSSM can well accommodate a light Higgs boson around 125 GeV and decay patterns. We would like to stress that the LHC direct supersymmetry searches with b tagging are very powerful and can set strong bounds on many NMSSM parameter points with light stops and sbottoms. We find $\tilde{t}\to b{\tilde{\chi }}_1^{+}$ is a very promising channel for light stop detection if the mass splitting between ${\tilde{\chi }}_1^{+}$ and ${\tilde{\chi }}_1^0$ is very small. It is also pointed out that in order to close the parameter space of light stops and sbottoms, new search strategies for signal channels such as $pp\to {\tilde{t}}_1{\tilde{t}}_1\to t\overline{t}hh{\tilde{\chi }}_1^0{\tilde{\chi }}_1^0$ and $pp\to {\tilde{b}}_1{\tilde{b}}_1\to t\overline{t}{W}^{+}{W}^{-}{\tilde{\chi }}_1^0{\tilde{\chi }}_1^0$ may be necessary.

If supersymmetry (SUSY) has a compressed spectrum the current limits from the LHC can be drastically reduced. We take possible “worst case” scenarios where combinations of the top squark, squark and gluino masses are degenerate with the mass of the lightest SUSY particle. To accurately derive limits in the model, care must be taken when describing QCD radiation and we examine this in detail. Lower mass bounds are then produced by considering all the 7 TeV hadronic SUSY and monojet searches. The evolution of the limits as the mass splitting is varied is also presented.

We introduce a perturbative extension of the standard model featuring a new dark matter sector together with a 125 GeV Higgs. The new sector consists of a vectorlike heavy electron ($E$), a complex scalar electron ($S$) and a standard model singlet Dirac fermion ($\chi$). The interactions among the dark matter candidate $\chi$ and the standard model particles occur via loop-induced processes involving the operator $S\overline{E}\chi y$, with $y$ being the Yukawa-like coupling. The model is an explicit underlying realization of the light magnetic dark matter effective model introduced earlier to alleviate the tension among several direct dark matter search experiments. We further constrain the parameters of the underlying theory using results from the Large Hadron Collider. The extension can accommodate the recently observed properties of the Higgs-like state and leads to interesting predictions. Finally, we show that the model’s collider phenomenology and constraints nicely complement the ones coming from dark matter searches.

Three-step cascade decays into two invisible particles and two visible particles via two intermediate on-shell particles develop cusped peak structures in several kinematic distributions. We study their basic properties and demonstrate that the masses of the missing particles and the intermediate particles can be determined by the cusp and endpoint positions. Effects from realistic considerations such as finite decay widths, the longitudinal boost of the mother particle, the initial state radiation, and spin correlations are shown to be under control for the processes illustrated.

The kinematics of a final state system with two invisible particles and two visible particles can develop cusped peak structures. This happens when the system has a fixed invariant mass (such as from a narrow resonant particle decay or with a fixed collision c.m. energy) and undergoes decays of two on-shell intermediate particles. Focusing on the antler decay topology, we derive general analytic expressions for the invariant mass distribution and the kinematic cusp position. The sharp cusp peaks and the endpoint positions can help to determine the masses of the missing particles and the intermediate particles. We also consider transverse momentum variables and angular variables. In various distributions the kinematic cusp peaks are present and pronounced. We also study the effects on such kinematic cusp structures from realistic considerations including finite decay widths, the longitudinal boost of the system, the initial state radiation, and spin correlations.

In a lattice QCD calculation with two light dynamical chirally improved quarks we determine ground state and some excited state masses in all four $\Lambda$ baryon channels $\frac{1}{2}\genfrac{}{}{0ex}{}{{\pm }^{}}{}$ and $\frac{3}{2}\genfrac{}{}{0ex}{}{{\pm }^{}}{}$. We perform an infinite volume extrapolation and confirm the widely discussed $\Lambda (1405)$. We also analyze the amount of octet-singlet mixing, which is helpful in comparing states with the quark model.

A first exploratory lattice QCD simulation is presented, aimed at extracting the masses and widths of the broad scalar $D_0^{*}(2400)$ and the axial $D_1(2430)$ charm-light resonances. For that purpose $D\pi$ and $D^{*}\pi$ scattering are simulated, and the resonance parameters are extracted using a Breit-Wigner fit of the resulting phase shifts. We use a single two-flavor dynamical ensemble with $m_{\pi }\approx 266\mathrm{MeV}$, $a\simeq 0.124\mathrm{fm}$ and a rather small volume $V={16}^3\times 32$. The resulting $D_0^{*}(2400)$ mass is $351\pm 21\mathrm{MeV}$ above the spin average $\frac{1}{4}(m_D+3m_{D^{*}})$, in agreement with the experimental value of $347\pm 29\mathrm{MeV}$ above. The resulting $D_0^{*}\to D\pi$ coupling, $g^{\mathrm{lat}}=2.55\pm 0.21\mathrm{GeV}$, is close to the experimental value $g^{\exp }\le 1.92\pm 0.14\mathrm{GeV}$, where $g$ parametrizes the width $\Gamma \equiv g^2{p}^{*}/s$. The resonance parameters for the broad $D_1(2430)$ are also found close to the experimental values; these are obtained by appealing to the heavy quark limit, where the neighboring resonance $D_1(2420)$ is narrow. The calculated $I=1/2$ scattering lengths are $a_0=0.81\pm 0.14\mathrm{fm}$ for $D\pi$ and $a_0=0.81\pm 0.17\mathrm{fm}$ for $D^{*}\pi$ scattering. The simulation of the scattering in these channels incorporates quark-antiquark as well as multihadron interpolators, and the distillation method is used for contractions. In addition, the ground and several excited charm-light and charmonium states with various $J^P$ are calculated using standard quark-antiquark interpolators.

By studying the color structure of multiparticle production processes in $\mathrm{p}+\mathrm{A}$-type (dilute-dense) collisions, we find that higher-point functions beyond typical dipoles and quadrupoles, e.g., sextupoles, octupoles, etc., naturally appear in the cross sections, but are explicitly suppressed in the large-$N_c$ limit. We evaluate the sextupole in the McLerran-Venugopalan model and find that, in general, its analytical form cannot be written as combination of dipoles and quadrupoles. Within the color glass condensate framework, we present a proof that in the large-$N_c$ limit, all multiparticle production processes in the collision of a dilute system off a dense system can, up to all orders in ${\alpha }_s$, be described in terms of only dipoles and quadrupoles.

The single-spin asymmetry of unpolarized leptons scattering deep-inelastically off transversely polarized nucleons is studied in a partonic picture within a collinear twist-3 framework. Since this observable is generated by multiphoton exchanges between a lepton and nucleon a partonic description of the asymmetry contains essential elements of a full next-to-leading order calculation for single-spin asymmetries in perturbative quantum chromodynamics. In particular, it is shown how nontrivial cancellations between kinematical and dynamical twist-3 contributions lead to a well-behaved and finite formula. This final result can be expressed in terms of multipartonic quark-gluon and quark-photon correlation functions. Hence, a measurement of the transverse target single-spin asymmetry may provide new constraints on these multipartonic correlations.

We investigate the implications of direct $CP$ violation (CPV) on the determination of the unitarity triangle angle $\gamma$ from $B\to DK$ decays. We show that $\gamma$ can still be extracted even with the inclusion of direct CPV in charm if (i) at least one of the $D$ decays has negligible $CP$ violation; and (ii) data from a charm factory at threshold are used. If approximate expressions without direct $CP$ violation in charm are used, this can result in a shift in $\gamma$ that is $\mathcal{O}(r_D/r_B)$. It is modest for $B\to DK$ but can be $\mathcal{O}(1)$ for $B\to D\pi$. We illustrate the size of the shift using an example of the Gronau-London-Wyler method.

We use a macroscopic description of a system of relativistic particles based on adding a nonequilibrium tensor to the usual hydrodynamic variables. The nonequilibrium tensor is linked to relativistic kinetic theory through a nonlinear closure suggested by the entropy production principle; the evolution equation is obtained by the method of moments and together with energy-momentum conservation closes the system. Transport coefficients are chosen to reproduce second-order fluid dynamics if gradients are small. We compare the resulting formalism to exact solutions of Boltzmann’s equation in $0+1$ dimensions and show that it tracks kinetic theory better than second-order fluid dynamics.

In this paper we assume the Higgs is an elementary scalar, and study how new physics could affect its couplings to electroweak gauge bosons. Adding LHC data to LEP data provides new, more stringent limits, particularly when the Higgs to two photon decay signal strength is taken into account. We then study the effect of anomalous angular correlations in the decay to WW*. We obtain a new limit on the rare decay to photon-$Z$, and use it to constrain supersymmetry, to find that staus with large mixing would be most sensitive to this channel. We also use these limits to constrain radion exchange in warped extra dimensions, finding a limit on the radion mass and interaction scale of the order of TeV. Finally, we have extrapolated the current data to obtain prospects for the full 2012 data set.

A measurement of the ${\Lambda }_b^0$ lifetime and mass in the decay channel ${\Lambda }_b^0\to J/\psi ({\mu }^{+}{\mu }^{-}){\Lambda }^0(p{\pi }^{-})$ is presented. The analysis uses a signal sample of about 2200 ${\Lambda }_b^0$ and ${\overline{\Lambda }}_b^0$ decays that are reconstructed in $4.9{\mathrm{fb}}^{-1}$ of ATLAS $pp$ collision data collected in 2011 at the LHC center-of-mass energy of 7 TeV. A simultaneous mass and decay time maximum likelihood fit is used to extract the ${\Lambda }_b^0$ lifetime and mass. They are measured to be ${\tau }_{{\Lambda }_b}=1.449\pm 0.036(\mathrm{stat})\pm 0.017(\mathrm{syst})\mathrm{ps}$ and $m_{{\Lambda }_b}=5619.7\pm 0.7(\mathrm{stat})\pm 1.1(\mathrm{syst})\mathrm{MeV}$.

In this paper we consider scalar-tensor theories, allowing for both conformal and disformal couplings to a fluid with a general equation of state. We derive the effective coupling for both background cosmology and for perturbations in that fluid. As an application we consider the scalar degree of freedom to be coupled to baryons and study the dynamics of the tightly coupled photon-baryon fluid in the early Universe. We derive an expression for the effective speed of sound, which differs from its value in General Relativity. We apply our findings to the $\mu$-distortion of the cosmic microwave background radiation, which depends on the effective sound-speed of the photon-baryon fluid, and show that the predictions differ from General Relativity. Thus, the $\mu$-distortion provides further information about gravity in the very early Universe well before decoupling.

We construct supersymmetric $Q$-balls and boson stars in $(d+1)$ dimensions. These nontopological solitons are solutions of a scalar field model with global $U(1)$ symmetry and a scalar field potential that appears in gauge-mediated supersymmetry breaking in the minimal supersymmetric extension of the standard model. We are interested in both the asymptotically flat as well as in the asymptotically anti-de Sitter (AdS) solutions. In particular, we show that for our choice of the potential gravitating, asymptotically flat boson stars exist in $(2+1)$ dimensions. We observe that the behavior of the mass and charge of the asymptotically flat solutions at the approach of the maximal frequency depends strongly on the number of spatial dimensions. In particular, we find that in the “thick-wall limit” $Q$-balls are always unstable in flat space-time, but that they can become stable in AdS. Moreover, for the asymptotically AdS solutions the model on the conformal boundary can be interpreted as describing $d$-dimensional condensates of scalar glueballs.