We improve the resummation calculations in the ResBos program for the Higgs boson production via gluon-gluon fusion by including the next-to-next-to-leading order Wilson coefficient functions and $G$ functions. The improvement leads to increasing the total cross section predictions of the new ResBos program, dubbed as ResBos2, for Higgs boson production by about 8 and 6% at the Tevatron and the LHC, respectively, as compared to the old ResBos program. Furthermore, the improved predictions are compared with those from the programs HNNLO and HqT2. We find that they agree well for the total cross sections but differ slightly for the transverse momentum $Q_T$ distributions. With ResBos2, we present the distributions of the two variables $a_T$ and ${\varphi }^{*}$, which can have better experimental resolutions than $Q_T$, for the process of a Higgs boson decaying into a photon pair. Theoretical uncertainties of the ResBos2 predictions are also discussed.

Nonrelativistic dark matter scattering with nucleons is constrained by direct detection experiments. We use the XENON constraints on the spin-independent and spin-dependent cross section for dark matter scattering with nucleons to constrain a hypothetical Majorana fermionic dark matter particle’s couplings to the Higgs boson and $Z$ boson. In this paper, we illustrate the change in the dark matter nucleon cross section as one goes from nonrelativistic, coherent scattering to relativistic, incoherent scattering. While the $Z$ invisible decay width excludes directly couplings of dark matter to ordinary matter, by introducing a light $Z^{\prime }$ portal to the dark sector, a relatively large dark matter nucleon cross section can be preserved even with accelerator experiment constraints for dark matter with a mass of $\sim 10\mathrm{GeV}$.

It has been argued recently that transverse asymmetries that are expected to be shielded from the presence of the $\mathrm{S}$-wave $K\pi$ pairs originating from the decay of a scalar $K_0^{*}$ meson, are indeed affected by this pollution due to the impossibility to extract cleanly the normalization for these observables. In this short article we show how using folded distributions, which is nowadays the preferred method to obtain the information from the 4-body decay mode $B\to K^{*}(\to K\pi )l^{+}{l}^{-}$, one can easily bypass this problem and extract the clean observables $P_{1,2,3}$ and also $P_{4,5,6}^{\prime }$ in a way completely free from this pollution including all lepton mass corrections. We also show that in case one insists in using uniangular distributions to extract these observables, it is possible to reduce this pollution to just lepton mass suppressed terms. On the contrary, the $S_i$ observables, that are by definition normalized by the full differential decay distribution, will indeed suffer from this pollution via their normalization. Finally, we also present a procedure to minimize the error associated to neglecting lepton mass corrections in the distribution defining a massless-improved limit.

We apply the MIT bag model to study the Boer-Mulders function of the pion, a $T$-odd function that describes the transverse polarization distribution of the quark inside the pion. We simulate the effect of the gauge link through the “one-gluon-exchange” approximation. We consider both the quark helicity nonflip and double-flip contributions. The result in the MIT bag model is compared with those in the spectator models.

With the progress of increasingly precise measurements on the neutrino mixing angles, phenomenological relations such as quark-lepton complementarity (QLC) among mixing angles of quarks and leptons and self-complementarity (SC) among lepton mixing angles have been observed. Using the latest global fit results of the quark and lepton mixing angles in the standard Chau-Keung scheme, we calculate the mixing angles and $CP$-violating phases in the other eight different schemes. We check the dependence of these mixing angles on the $CP$-violating phases in different phase schemes. The dependence of QLC and SC relations on the $CP$ phase in the other eight schemes is recognized and then analyzed, suggesting that measurements on $CP$-violating phases of the lepton sector are crucial to the explicit forms of QLC and SC in different schemes.

We discuss the minimal supersymmetric $U(1{)}_{B-L}\times U(1{)}_R$ extension of the standard model. Gauge couplings unify as in the minimal supersymmetric standard model (MSSM), even if the scale of $U(1{)}_{B-L}\times U(1{)}_R$ breaking is as low as order TeV and the model can be embedded into a $SO(10)$ grand unified theory. The phenomenology of the model differs in some important aspects from the MSSM, leading potentially to rich phenomenology at the LHC. It predicts more light Higgs states and the mostly left $CP$-even Higgs having a mass that easily reaches 125 GeV, with no constraints on the supersymmetry spectrum. Right sneutrinos can be the lightest supersymmetric particle, changing all dark matter constraints on supersymmetry parameter space. The model has seven neutralinos, and squark/gluino decay chains involve more complicated cascades than in the MSSM. We also briefly discuss low-energy and accelerator constraints on the model, where the most important limits come from recent $Z^{\prime }$ searches at the LHC and upper limits on lepton flavor violation.

We consider the Hamiltonian formulation of Yang-Mills theory in the Coulomb gauge and apply the recently developed technique of Hamiltonian flows. We formulate a flow equation for the color Coulomb potential which allows for a scaling solution that results in an almost linearly rising confining potential.

The dilaton action in $3+1$ dimensions plays a crucial role in the proof of the a-theorem. This action arises using Wess-Zumino consistency conditions and crucially relies on the existence of the trace anomaly. Since there are no anomalies in odd dimensions, it is interesting to ask how such an action could arise otherwise. Motivated by this we use the AdS/CFT correspondence to examine both even and odd dimensional conformal field theories. We find that in even dimensions, by promoting the cutoff to a field, one can get an action for this field which coincides with the Wess-Zumino action in flat space. In three dimensions, we observe that by finding an exact Hamilton-Jacobi counterterm, one can find a nonpolynomial action which is invariant under global Weyl rescalings. We comment on how this finding is tied up with the F-theorem conjectures.

We investigate the high-energy properties of matter theories coupled to quantum gravity. Specifically, we show that quantum gravity fluctuations generically induce matter self-interactions in a scalar theory. Our calculations apply within asymptotically safe quantum gravity, where our results indicate that the UV is dominated by an interacting fixed point, with nonvanishing gravitational as well as matter couplings. In particular, momentum-dependent scalar self-interactions are nonzero and induce a nonvanishing momentum-independent scalar potential. Furthermore, we point out that terms of this type can have observable consequences in the context of scalar-field driven inflation, where they can induce potentially observable non-Gaussianities in the cosmic microwave background.

Large $N_c$ and holographic arguments, as well as Monte Carlo results, suggest that the topological structure of the QCD vacuum is dominated by codimension-one membranes which appear as thin dipole layers of topological charge. Such membranes arise naturally as $D6$-branes in the holographic formulation of QCD based on IIA string theory. The polarizability of these membranes leads to a vacuum energy $\propto {\theta }^2$, providing the origin of nonzero topological susceptibility. Here we show that the axial U(1) anomaly can be formulated as anomaly inflow on the brane surfaces. A 4D gauge transformation at the brane surface separates into a 3D gauge transformation of components within the brane and the transformation of the transverse component. The in-brane gauge transformation induces currents of an effective Chern-Simons theory on the brane surface, while the transformation of the transverse component describes the transverse motion of the brane and is related to the Ramond-Ramond closed string field in the holographic formulation of QCD. The relation between the surface currents and the transverse motion of the brane is dictated by the descent equations of Yang-Mills theory.

We study the horizon absorption of gravitational waves in coalescing, circularized, nonspinning black-hole binaries. The horizon-absorbed fluxes of a binary with a large mass ratio ($q=1000$) obtained by numerical perturbative simulations are compared with an analytical, effective-one-body (EOB) resummed expression recently proposed. The perturbative method employs an analytical, linear in the mass ratio, EOB-resummed radiation reaction, and the Regge-Wheeler-Zerilli formalism for wave extraction. Hyperboloidal layers are employed for the numerical solution of the Regge-Wheeler-Zerilli equations to accurately compute horizon fluxes up to the late plunge phase. The horizon fluxes from perturbative simulations and the EOB-resummed expression agree at the level of a few percent down to the late plunge. An upgrade of the EOB model for nonspinning binaries that includes horizon absorption of angular momentum as an additional term in the resummed radiation reaction is then discussed. The effect of this term on the waveform phasing for binaries with mass ratios spanning 1–1000 is investigated. We confirm that for comparable and intermediate-mass-ratio binaries horizon absorption is practically negligible for detection with advanced LIGO and the Einstein Telescope ($\mathrm{\text{faithfulness}}\ge 0.997$).

One way to select a preferred frame from gravitational radiation is via the principal axes of $⟨{\mathcal{L}}_{(a}{\mathcal{L}}_{b)}⟩$, an average of the action of rotation group generators on the Weyl tensor at asymptotic infinity. In this paper we evaluate this time-domain average for a quasicircular binary using approximate (post-Newtonian) waveforms. For nonprecessing unequal-mass binaries, we show the dominant eigenvector of this tensor lies along the orbital angular momentum. For precessing binaries, this frame is not generally aligned with either the orbital or total angular momentum, working to leading order in the spins. The difference between these two quantities grows with time, as the binary approaches the end of the inspiral and both precession and higher harmonics become more significant.

Geometric properties of the quasihyperbolic Szekeres models are discussed and related to the quasispherical Szekeres models. Typical examples of shapes of various classes of two-dimensional coordinate surfaces are shown in graphs, for the hyperbolically symmetric subcase and for the general quasihyperbolic case. An analysis of the mass function $M(z)$ is carried out in parallel to an analogous analysis for the quasispherical models. This leads to the conclusion that $M(z)$ determines the density of rest mass averaged over the whole space of constant time.

We study the gravitational collapse of a magnetized neutron star using a novel numerical approach able to capture both the dynamics of the star and the behavior of the surrounding plasma. In this approach, a fully general relativistic magnetohydrodynamics implementation models the collapse of the star and provides appropriate boundary conditions to a force-free model which describes the stellar exterior. We validate this strategy by comparing with known results for the rotating monopole and aligned rotator solutions and then apply it to study both rotating and nonrotating stellar collapse scenarios and contrast the behavior with what is obtained when employing the electrovacuum approximation outside the star. The nonrotating electrovacuum collapse is shown to agree qualitatively with a Newtonian model of the electromagnetic field outside a collapsing star. We illustrate and discuss a fundamental difference between the force-free and electrovacuum solutions, involving the appearance of large zones of electric-dominated field in the vacuum case. This provides a clear demonstration of how dissipative singularities appear generically in the nonlinear time evolution of force-free fluids. In both the rotating and nonrotating cases, our simulations indicate that the collapse induces a strong electromagnetic transient, which leaves behind an uncharged, unmagnetized Kerr black hole. In the case of submillisecond rotation, the magnetic field experiences strong winding, and the transient carries much more energy. This result has important implications for models of gamma-ray bursts. Even when the neutron star is surrounded by an accretion torus (as in binary merger and collapsar scenarios), a magnetosphere may emerge through a dynamo process operating in a surface shear layer. When this rapidly rotating magnetar collapses to a black hole, the electromagnetic energy released can compete with the later output in a Blandford-Znajek jet. Much less electromagnetic energy is released by a massive magnetar that is (initially) gravitationally stable: its rotational energy is dissipated mainly by internal torques. A distinct plasmoid structure is seen in our nonrotating simulations, which will generate a radio transient with subluminal expansion and greater synchrotron efficiency than is expected in shock models. Closely related phenomena appear to be at work in the giant flares of Galactic magnetars.

We consider a model of $F(R)$ gravity in which exponential and power corrections to Einstein-$\Lambda$ gravity are included. We show that this model has four-dimensional Eguchi-Hanson-type instanton solutions in Euclidean space. We then seek solutions to the five-dimensional equations for which space-time contains a hypersurface corresponding to the Eguchi-Hanson space. We obtain analytic solutions of the $F(R)$ gravitational field equations and, by assuming certain relationships between the model parameters and integration constants, find several classes of exact solutions. Finally, we investigate the asymptotic behavior of the solutions and compute the second derivative of the $F(R)$ function with respect to the Ricci scalar to confirm Dolgov-Kawasaki stability.

When Lorentz invariance is violated at high energy, the laws of black hole thermodynamics are apparently no longer satisfied. To shed light on this observation, we study dispersive fields in de Sitter space. We show that the Bunch-Davies vacuum state restricted to the static patch is no longer thermal, and that the Tolman law is violated. However we also show that, for free fields at least, this vacuum is the only stationary stable state, as if it were in equilibrium. We then present a precise correspondence between dispersive effects found in de Sitter and in black hole metrics. This indicates that the consequences of dispersion on thermodynamical laws could also be similar.

We consider the simplest versions of the Nambu–Jona-Lasinio model and the linear sigma model, in the mean field approximation, in order to analyze hot and dense two flavor quark matter subject to strong magnetic fields. We pay special attention to the case of a finite chemical potential, which has not yet been fully explored. Our results, for the Nambu–Jona-Lasinio model, are in qualitative agreement with other recent applications showing that, for stronger fields, the first order segment of the transition line increases with the magnetic strength while the coexistence chemical potential value, at low temperatures, decreases. In the present work, one of the most important results is related to the analysis of how these features affect the phase coexistence region in the $T\mathrm{\text{−}}{\rho }_B$ plane. We find that the coexistence boundary oscillates around the $B=0$ value for magnetic fields of the order $eB\lesssim 9.5m_{\pi }^2$, which can be understood by investigating the filling of Landau levels at vanishing temperature. So far, most investigations have been concerned with the effects of the magnetic field over the $T\mathrm{\text{−}}\mu$ plane only while other thermodynamical quantities such as the adiabats, the quark number susceptibility, the interaction measure and the latent heat have been neglected. Here, we take a step towards filling this gap by investigating the influence of a magnetic field over these quantities. Finally, we argue that a naive application of the mean field approximation does not seem to be appropriate to treat the linear sigma model in the presence of magnetic fields.

If the lightest supersymmetric particle (LSP) is Higgsino-like, the thermal relic density is lower than the observed dark matter content for a LSP mass in the sub-TeV region. We outline constraints arising from the Fermi Gamma-ray Telescope data and LSP production from gravitino decay that must be satisfied by a successful nonthermal Higgsino scenario. We show that in a generic class of models where anomaly- and modulus-mediated contributions to supersymmetry breaking are of comparable size, Higgsino arises as the only viable sub-TeV dark matter candidate if gravitinos are heavy enough to decay before the onset of big bang nucleosynthesis. The correct relic density can be obtained via modulus decay in these models. As an explicit example, we consider a modulus sector in effective field theory ($D=4$, $N=1$ supergravitiy arising from type IIB Kachru-Kallosh-Linde-Trivedi compactification). Within this class of mirage mediation models, heaviness of the gravitino forces a sub-TeV Higgsino LSP and gives a Higgs mass around 125 GeV. In this example, the constraints from direct detection experiments are also satisfied.

We calculate the vacuum to meson matrix elements of the dimension-4 operator $\overline{\psi }{\gamma }_4{\overleftrightarrow{D}}_i\psi$ and dimension-5 operator $\overline{\psi }{\epsilon }_{ijk}{\gamma }_j\psi B_k$ of the $1^{-+}$ meson on the lattice and compare them to the corresponding matrix elements of the ordinary mesons to discern if it is a hybrid. For the charmoniums and strange quarkoniums, we find that the matrix elements of $1^{-+}$ are comparable in size as compared to other known $q\overline{q}$ mesons. They are particularly similar to those of the $2^{++}$ meson, since their dimension-4 operators are in the same Lorentz multiplet. Based on these observations, we find no evidence to support the notion that the lowest $1^{-+}$ mesons in the $c\overline{c}$ and $s\overline{s}$ regions are hybrids. As far as the exotic quantum number is concerned, the nonrelativistic reduction reveals that the leading terms in the dimension-4 and dimension-5 operators of $1^{-+}$ are identical up to a proportional constant and it involves a center-of-mass momentum operator of the quark-antiquark pair. This explains why $1^{-+}$ is an exotic quantum number in the constituent quark model where the center of mass of the $q\overline{q}$ is not a dynamical degree of freedom. Since QCD has gluon fields in the context of the flux tube which is appropriate for heavy quarkoniums to allow the valence $q\overline{q}$ to recoil against them, it can accommodate such states as $1^{-+}$. By the same token, hadronic models with additional constituents besides the quarks can also accommodate the $q\overline{q}$ center-of-mass motion. To account for the quantum numbers of these $q\overline{q}$ mesons in QCD and hadron models in the nonrelativistic case, the parity and total angular momentum should be modified to $P=(-{)}^{L+l+1}$ and $\overrightarrow{J}=\overrightarrow{L}+\overrightarrow{l}+\overrightarrow{S}$, where $L$ is the orbital angular momentum of the $q\overline{q}$ pair in the meson.

Nonleptonic two-body $B$ decays including radially excited $\pi (1300)$ or $\rho (1450)$ mesons in the final state are studied using the framework of a generalized naive factorization approach. Branching ratios and $CP$ asymmetries of $B\to P\pi (1300)$, $B\to V\pi (1300)$, $B\to P\rho (1450)$ and $B\to V\rho (1450)$ decays are calculated, where $P$ and $V$ stand for pseudoscalar and vector charmless mesons. Form factors for $B\to \pi (1300)$ and $B\to \rho (1450)$ transitions are estimated in the improved version of the Isgur-Scora-Grinstein-Wise quark model. In some processes, $CP$ asymmetries of more than 10% and branching ratios of ${10}^{-5}$ order are found, which could be reached in experiments.