Higgs production from gluon fusion is sensitive to the properties of heavy colored fermions and to the Yukawa couplings, $\frac{Y_F{M}_F}{v}$, of these particles to the Higgs boson. We compute the two-loop, $\mathcal{O}({(\frac{Y_F{M}_F}{v})}^3)$ contributions of new high mass fermions to Higgs production. In the Standard Model, these contributions are part of the well-known electroweak corrections and are negligible. However, in models with TeV scale fermions, such as top partner or composite models, Yukawa corrections are enhanced by effects of $\mathcal{O}({(\frac{Y_F{M}_F}{v})}^3)$ and are potentially significant due to the large mass of the new quarks. We examine the size of these top partner Yukawa corrections to Higgs production for parameter choices which are allowed by precision electroweak constraints.

The existence of old neutron stars deeply constrains self-interacting fermion dark matter, which can form star-killing black holes. We quantify this constraint on dark matter-nucleon scattering, considering collapse scenarios that broaden bounds over intermediate masses. We then find the self-annihilation and coannihilation rates necessary to lift these dark matter-nucleon scattering bounds. For Yukawa-coupled dark matter that fits dwarf galaxy halo profiles with a coupling $\alpha =10^{-1}–10^{-4}$, a scalar mediator mass $m_{\varphi }=1–500\mathrm{MeV}$, and dark matter mass $m_X=0.1–10^7\mathrm{GeV}$, we show that fermion dark matter is unconstrained if it self-annihilates at a rate greater than $10^{-40}{\mathrm{cm}}^3/\mathrm{s}$ or coannihilates with baryons at a rate greater than $10^{-50}{\mathrm{cm}}^3/\mathrm{s}$.

The contribution of the higher-twist mechanism to the large-$p_T$ inclusive gluon production cross section in $\pi p$ collisions is calculated in the case of the principle of maximum conformality and Brodsky-Lepage-Mackenzie approaches in the dependence of the pion distribution amplitudes. The higher-twist cross sections are obtained in the framework of the principle of maximum conformality and Brodsky-Lepage-Mackenzie approaches, and compared and analyzed in relation to the leading-twist cross sections and each other.

In this work we study the implication of the nonuniversal $Z^{\prime }$ model to the double lepton polarization asymmetries in the $B\to K^{*}{\ell }^{+}{\ell }^{-}$, $(l=\mu ,\tau )$ decay. To see the variation in the values of lepton polarization asymmetries from the standard model values, we have taken bounds of the UTfit collaboration, namely, $S_1$ and $S_2$ on the values of different parameters of the universal $Z^{\prime }$ model such as left-right couplings of the extra gauge boson with leptons and the new weak phase ${\varphi }_{sb}$. It is found that double lepton polarization asymmetries are sensitive to the coupling parameters of $Z^{\prime }$ boson with fermions. Therefore, the measurements of these lepton polarization asymmetries for the above-mentioned decay at current colliders can be helpful to clarify the status of the existence of the extra gauge boson, i.e., $Z^{\prime }$.

A search for the standard model Higgs boson ($H$) decaying to $b\overline{b}$ when produced in association with a weak vector boson ($V$) is reported for the following channels: $W(\mu \nu )H$, $W(e\nu )H$, $W(\tau \nu )H$, $Z(\mu \mu )H$, $Z(ee)H$, and $Z(\nu \nu )H$. The search is performed in data samples corresponding to integrated luminosities of up to 5.1 inverse femtobarns at $\sqrt{s}=7\mathrm{TeV}$ and up to $18.9{\mathrm{fb}}^{-1}$ at $\sqrt{s}=8\mathrm{TeV}$, recorded by the CMS experiment at the LHC. An excess of events is observed above the expected background with a local significance of 2.1 standard deviations for a Higgs boson mass of 125 GeV, consistent with the expectation from the production of the standard model Higgs boson. The signal strength corresponding to this excess, relative to that of the standard model Higgs boson, is $1.0\pm 0.5$.

In this paper, we use the appropriate boundary action for the vector fields near the horizon of the near extremal Kerr black hole to calculate the two-point function for the vector fields in Kerr/CFT correspondence. We show the gauge-independent part of the two-point function is in agreement with what is expected from CFT.

The dark matter halo of the Milky Way is predicted to contain a very large number of smaller subhalos. As a result of the dark matter annihilations taking place within such objects, the most nearby and massive subhalos could appear as pointlike or spatially extended gamma-ray sources, without observable counterparts at other wavelengths. In this paper, we use the results of the Aquarius simulation to predict the distribution of nearby subhalos and compare this to the characteristics of the unidentified gamma-ray sources observed by the Fermi Gamma-Ray Space Telescope. Focusing on the brightest high latitude sources, we use this comparison to derive limits on the dark matter annihilation cross section. For dark matter particles lighter than $\sim 200\mathrm{GeV}$, the resulting limits are the strongest obtained to date, being modestly more stringent than those derived from observations of dwarf galaxies or the Galactic center. We also derive independent limits based on the lack of unidentified gamma-ray sources with discernible spatial extension, but these limits are a factor of $\sim 2–10$ weaker than those based on pointlike subhalos. Lastly, we note that four of the ten brightest high-latitude sources exhibit a similar spectral shape, consistent with 30–60 GeV dark matter particles annihilating to $b\overline{b}$ with an annihilation cross section on the order of $\sigma v\sim (5–10)\times 10^{-27}{\mathrm{cm}}^3/\mathrm{s}$ or 8–10 GeV dark matter particles annihilating to ${\tau }^{+}{\tau }^{-}$ with $\sigma v\sim (1.5–3.0)\times 10^{-27}{\mathrm{cm}}^3/\mathrm{s}$.

We develop a method to determine accurately the binding energy of the X(3872) from lattice data for the $D{\overline{D}}^{*}$ interaction. We show that, because of the small difference between the neutral and charged components of the X(3872), it is necessary to differentiate them in the energy levels of the lattice spectrum if one wishes to have a precise determination of the the binding energy of the X(3872). The analysis of the data requires the use of coupled channels. Depending on the number of levels available and the size of the box, we determine the precision needed in the lattice energies to finally obtain a desired accuracy in the binding energy.

We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cross correlations with the cosmic microwave background. We update the data sets used by Giannantonio et al. (2012), and broaden that analysis to include the full set of two-point correlation functions between all surveys. In order to obtain the most reliable constraints on PNG, we advocate the use of the cross correlations between the catalogs as a robust estimator and we perform an extended analysis of the possible systematics to reduce their impact on the results. To minimize the impact of stellar contamination in our luminous red galaxy sample, we use the recent Baryon Oscillations Spectroscopic Survey catalog of Ross et al. (2011). We also find evidence for a new systematic in the NVSS radio galaxy survey similar to, but smaller than, the known declination-dependent issue; this is difficult to remove without affecting the inferred PNG signal, and thus we do not include the NVSS autocorrelation function in our analyses. We find no evidence of primordial non-Gaussianity; for the local-type configuration we obtain for the skewness parameter $-36<f_{\mathrm{NL}}<45$ at 95% C.L. ($5\pm 21$ at $1\sigma$) when using the most conservative part of our data set, improving previous results; we also find no evidence for significant kurtosis, parameterized by $g_{\mathrm{NL}}$. In addition to PNG, we simultaneously constrain dark energy and find that it is required with a form consistent with a cosmological constant.

We adopt the conduction fluid approximation to model the steady-state distribution of matter around a massive black hole at the center of a weakly collisional cluster of particles. By “weakly collisional” we mean a cluster in which the mean free time between particle collisions is much longer than the characteristic particle crossing (dynamical) time scale, but shorter than the cluster lifetime. When applied to a star cluster, we reproduce the familiar Bahcall-Wolf power-law cusp solution for the stars bound to the black hole. Here the star density scales with radius as $r^{-7/4}$ and the velocity dispersion as $r^{-1/2}$ throughout most of the gravitational well of the black hole. When applied to a relaxed, self-interacting dark matter (SIDM) halo with a velocity-dependent cross section $\sigma \sim v^{-a}$, the gas again forms a power-law cusp, but now the SIDM density scales as $r^{-\beta }$, where $\beta =(a+3)/4$, while its velocity dispersion again varies as $r^{-1/2}$. Results are obtained first in Newtonian theory and then in full general relativity. Although the conduction fluid model is a simplification, it provides a reasonable first approximation to the matter profiles and is much easier to implement than a full Fokker-Planck treatment or an $N$-body simulation of the Boltzmann equation with collisional perturbations.

Primordial isocurvature fluctuations between photons and either neutrinos or nonrelativistic species such as baryons or dark matter are known to be subdominant to adiabatic fluctuations. Perturbations in the relative densities of baryons and dark matter (known as compensated isocurvature perturbations or CIPs), however, are surprisingly poorly constrained. CIPs leave no imprint in the cosmic microwave background (CMB) on observable scales, at least at linear order in their amplitude and zeroth order in the amplitude of adiabatic perturbations. It is thus not yet empirically known if baryons trace dark matter at the surface of last scattering. If CIPs exist, they would spatially modulate the Silk damping scale and acoustic horizon, causing distinct fluctuations in the CMB temperature/polarization power spectra across the sky: this effect is first order in both the CIP and adiabatic mode amplitudes. Here, temperature data from the Wilkinson Microwave Anisotropy Probe (WMAP) are used to conduct the first CMB-based observational search for CIPs, using off-diagonal correlations and the CMB trispectrum. Reconstruction noise from weak lensing and point sources is shown to be negligible for this data set. No evidence for CIPs is observed, and a 95% confidence upper limit of $1.1\times {10}^{-2}$ is imposed to the amplitude of a scale-invariant CIP power spectrum. This limit agrees with CIP sensitivity forecasts for WMAP and is competitive with smaller-scale constraints from measurements of the baryon fraction in galaxy clusters. It is shown that the root-mean-squared CIP amplitude on 5–100° scales is smaller than $\sim 0.07–0.17$ (depending on the scale) at the 95% confidence level. Temperature data from the Planck satellite will provide an even more sensitive probe for the existence of CIPs, as will the upcoming ACTPol and SPTPol experiments on smaller angular scales.

The hemispherical power asymmetry in the cosmic microwave background can be explained by the modulation of some primordial cosmological parameters, such as the sound speed of the inflaton. Inspired by new physics beyond the standard knowledge of particle cosmology, this sound speed modulation greatly enriches the cosmological perturbation theory. We numerically examine the mechanism of the sound speed modulation and show it can be nicely consistent with current observations. Furthermore, this mechanism predicts that power asymmetry also exists in the temperature-polarization correlation and polarization autocorrelation of the cosmic microwave background with the same shape and in primordial non-Gaussianity of equilateral type with a particular shape. Therefore, our mechanism is observationally detectable in the forthcoming experiments.

Our motion relative to the cosmic microwave background (CMB) rest frame deflects light rays giving rise to shifts as large as $\ell \to \ell (1\pm \beta )$, where $\beta =0.00123$ is our velocity (in units of the speed of light) on measurements of CMB fluctuations. Here we present a novel harmonic-space approach to this CMB aberration that improves upon prior work by allowing us to (i) go to higher orders in $\beta$, thus extending the validity of the analysis to measurements at $\ell \gtrsim {\beta }^{-1}\simeq 800$; and (ii) treat the effects of window functions and pixelization in a more accurate and computationally efficient manner. We calculate precisely the magnitude of the systematic bias in the power spectrum inferred from the partial sky and show that aberration shifts the multipole moment by $\mathrm{\Delta }\ell /\ell \simeq \beta ⟨\cos \theta ⟩$, with $⟨\cos \theta ⟩$ averaged over the survey footprint. Such a shift, if ignored, would bias the measurement of the sound-horizon size ${\theta }_{\text{*}}$ at the 0.01% level, which is comparable to the measurement uncertainties of Planck. The bias can then propagate into cosmological parameters such as the angular-diameter distance, Hubble parameter and dark-energy equation of state. We study the effect of aberration for current Planck, South Pole Telescope (SPT) and Atacama Cosmology Telescope (ACT) data and show that the bias cannot be neglected. On the other hand, the aberration effect yields the opposite sign of the discrepancy and cannot account for the small tension between ACT and SPT. An Appendix shows how the near constancy of the full-sky power spectrum under aberration follows from unitarity of the aberration kernel.

The “WIMP miracle” for the relic abundance of thermal dark matter motivates weak scale dark matter with renormalizable couplings to standard model particles. We study minimal models with such couplings that explain dark matter as a thermal relic. The models contain a singlet dark matter particle with cubic renormalizable couplings between standard model particles and “partner” particles with the same gauge quantum numbers as the standard model particle. The dark matter has spin 0, $\frac{1}{2}$, or 1, and may or may not be its own antiparticle. Each model has 3 parameters: the masses of the dark matter and standard model partners, and the cubic coupling. Requiring the correct relic abundance gives a 2-dimensional parameter space where collider and direct detection constraints can be directly compared. We focus on the case of dark matter interactions with colored particles. We find that collider and direct detection searches are remarkably complementary for these models. Direct detection limits for the cases where the dark matter is not its own antiparticle require dark matter masses to be in the multi-TeV range, where they are extremely difficult to probe in collider experiments. The models where dark matter is its own antiparticle are strongly constrained by collider searches for monojet and $\text{jets}+\mathrm{MET}$ signals. These models are constrained by direct detection mainly near the limit where the dark matter and partner masses are nearly degenerate, where collider searches become more difficult.

It has been suggested that electroweak symmetry breaking in the standard model may be natural if the standard model merges into a conformal field theory (CFT) at short distances. In such a scenario the Higgs mass would be protected from quantum corrections by the scale invariance of the CFTİn order for the standard model to merge into a CFT at least one new UV scale is required at which the couplings turn over from their usual standard model running to the fixed point behavior. We argue that the Higgs mass is sensitive to such a turn-over scale even if there are no associated massive particles and the scale arises purely from dimensional transmutation. We demonstrate this sensitivity to the turnover scale explicitly in toy models. Thus if scale invariance is responsible for Higgs mass naturalness, then the transition to CFT dynamics must occur near the TeV scale with observable consequences at colliders. In addition, the UV fixed point theory in such a scenario must be interacting because logarithmic running near a free fixed point constitutes hard breaking of scale invariance and spoils the Higgs mass protection.

The effects of the new neutral $Z^{\prime }$ boson in $B_s\to \phi {\ell }^{+}{\ell }^{-}$, when $\phi$ is longitudinal or transverse polarized, are studied. In addition, the implications of the $Z^{\prime }$ boson on the unpolarized and polarized $CP$ violation asymmetries, with reference to leptons, are also presented. It is observed that the branching ratio with polarized $\phi$ is quite sensitive to the $Z^{\prime }$ contributions which are coming through the modification of the Wilson coefficients $C_9^{\text{eff}}$ and $C_{10}$. Moreover, the off-diagonal elements of the chiral $Z^{\prime }$ couplings contain a new weak phase ${\phi }_{sb}$ that provides a new source of $CP$ violation. Keeping in view that in the flavor-changing neutral-current transitions, the $CP$-violation asymmetries are highly suppressed in the Standard Model, we have studied the unpolarized and polarized $CP$-violation asymmetries in $B_s\to \phi {\ell }^{+}{\ell }^{-}$ decays. Our results indicate that these $CP$-violation asymmetries are remarkably significant and can give us hints of any new physics coming through the $Z^{\prime }$ boson. It is hoped that accurate measurements of these asymmetries will not only help us to establish NP but also give us a chance to determine the precise values of the coupling parameters of the $Z^{\prime }$ boson.

We propose an evolution equation for unintegrated gluon densities that is valid for large values of the QCD coupling constant ${\overline{\alpha }}_s$. Our approach is based on the linear resummation model introduced by Staśto. We generalize the model including a nonlinear term in the diffusive regime. The validity of the diffusive evolution at strong coupling is supported by the AdS/CFT consideration, as well as perturbative arguments. We solve the evolution equation numerically and extract the saturation scale, which we compare with the weak coupling counterpart.

A new class of conserved currents, describing nongravitational energy-momentum density, is presented. The proposed currents do not require the existence of a (timelike) Killing vector, and are not restricted to spherically symmetric spacetimes (or similar ones, in which the Kodama vector can be defined). They are based instead on almost-Killing vectors, which could in principle be defined on generic spacetimes. We provide local arguments, based on energy density profiles in highly simplified (stationary, rigidly rotating) star models, which confirm the physical interest of these almost-Killing currents. A mass function is defined in this way for the spherical case, qualitatively different from the Hernández-Misner mass function. An elliptic equation determining the new mass function is derived for the Tolman-Bondi spherically symmetric dust metrics, including a simple solution for the Oppenheimer-Snyder collapse. The equations for the nonsymmetric case are shown to be of a mixed elliptic-hyperbolic nature.

We construct the quantum mechanical model of the Colella-Overhauser-Werner (COW) experiment assuming that the underlying space time has a granular structure, described by a canonical noncommutative algebra of coordinates $x^{\mu }$. The time-space sector of the algebra is shown to add a mass-dependent contribution to the gravitational acceleration felt by neutron de Brogli waves measured in a COW experiment. This makes time-space noncommutativity a potential candidate for an apparent violation of the weak equivalence principle even if the ratio of the inertial mass $m_i$ and gravitational mass $m_g$ is a universal constant. The latest experimental result based on the COW principle is shown to place an upper bound several orders of magnitude stronger than the existing one on the time-space noncommutative parameter. We argue that the evidence of noncommutative structure of space-time may be found if the COW-type experiment can be repeated with several particle species.

We explore the consequences of loop quantum cosmology (inverse-volume corrections) in the spectrum of the gravitational waves using the method of the Bogoliubov coefficients. These corrections are taken into account at the background level of the theory as well as at the first order in the perturbations theory framework. We show that these corrections lead to an intense graviton production during the loop superinflationary phase prior to the standard slow-roll era, which leave their imprints through new features on the energy spectrum of the gravitational waves as would be measured today, including a new maximum on the low frequency end of the spectrum.