We propose that the LHC hints for a Higgs diphoton excess and the muon $g-2(g_{\mu }-2)$ discrepancy between theory and experiment may be related by vectorlike “leptons” charged under both $U(1{)}_Y$ hypercharge and a “dark” $U(1{)}_d$. Quantum loops of such leptons can enhance the Higgs diphoton rate and also generically lead to $U(1{)}_Y\mathrm{\text{−}}U(1{)}_d$ kinetic mixing. The induced coupling of a light $U(1{)}_d$ gauge boson $Z_d$ to electric charge can naturally explain the measured $g_{\mu }-2$. We update $Z_d$ mass and coupling constraints based on comparison of the electron $g-2$ experiment and theory, and find that explaining $g_{\mu }-2$ while satisfying other constraints requires $Z_d$ to have a mass $\sim 20–100\mathrm{MeV}$. We predict new Higgs decay channels $\gamma Z_d$ and $Z_d{Z}_d$, with rates below the diphoton mode but potentially observable. The boosted $Z_d\to e^{+}{e}^{-}$ in these decays would mimic a promptly converted photon and could provide a fraction of the apparent diphoton excess. More statistics or a closer inspection of extant data may reveal such events.

We investigate the effect induced by the Kaluza-Klein (KK) graviton in the $W^{+}{W}^{-}\gamma /Z$ production in the framework of the large extra dimensions (LED) model at both the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). The integrated cross sections and various kinematic distributions in the LED model are presented and compared with those in the standard model. The results show that the contributions from KK-graviton exchange remarkably affect the observables of the triple gauge boson ($W^{+}{W}^{-}\gamma /Z$) production processes at both the ILC and LHC, particularly either in the high transverse momentum region or in the central rapidity region. We also find that the relative LED discrepancy for the $W^{+}{W}^{-}\gamma /Z$ production at the LHC is generally larger than that at the ILC due to the additional LED contribution via $gg$ fusion subprocess and the KK-graviton exchanging resonant effect induced by the continuous large colliding energy in $pp$ collision. We conclude that the $W^{+}{W}^{-}\gamma$ and $W^{+}{W}^{-}Z$ productions at the LHC could have the distinct advantage over at the ILC from the aspect of effectively exploring the LED signal in measuring $W^{+}{W}^{-}\gamma /Z$ production.

We show how the leading physical and Wilson low-energy constants associated with Wilson fermions in lattice gauge theory can be determined individually by using spectral information of the Wilson Dirac operator with fixed index at finite volume. The methods are demonstrated in simulations with leading-order improved Wilson fermions. In addition to the expected suppression of the leading term in Wilson chiral perturbation theory we observe a substantial reduction also of the higher-order Wilson low-energy constants.

We study the nuclear enhancement of the transverse momentum imbalance for back-to-back particle production in both $p+A$ and $e+A$ collisions. Specifically, we present results for $\mathrm{\text{photon}}+\mathrm{\text{jet}}$ and $\mathrm{\text{photon}}+\mathrm{\text{hadron}}$ production in $p+A$ collisions, di-jet and di-hadron production in $e+A$ collisions, and heavy-quark and heavy-meson pair production in both $p+A$ and $e+A$ collisions. We evaluate the effect of both initial-state and final-state multiple scattering, which determine the strength of the nuclear-induced transverse momentum imbalance in these processes. We give theoretical predictions for the experimentally relevant kinematic regions in $d+Au$ collisions at Relativistic Heavy Ion Collider, $p+Pb$ collisions at Large Hadron Collider and $e+A$ collisions at the future Electron Ion Collider and Large Hadron Electron Collider.

We investigate single-inclusive high-$p_T$ jet production in longitudinally polarized $pp$ collisions at the Relativistic Heavy Ion Collider, with particular focus on the algorithm adopted to define the jets. Following and extending earlier work in the literature, we treat the jets in the approximation that they are rather narrow, in which case analytical results for the corresponding next-to-leading order partonic cross sections can be obtained. This approximation is demonstrated to be very accurate for practically all relevant situations, even at Tevatron and LHC energies. We confront results for cross sections and spin asymmetries based on using cone and $k_t$-type jet algorithms. We find that jet cross sections at the Relativistic Heavy Ion Collider can differ significantly depending on the algorithm chosen, but that the spin asymmetries are rather robust. Our results are also useful for matching threshold-resummed calculations of jet cross sections to fixed-order ones.

We propose a simple extension of the electroweak standard model based on the discrete $S_3$ symmetry that is capable of realizing a nearly minimal Fritzsch-type texture for the Dirac mass matrices of both charged leptons and neutrinos. This is achieved with the aid of additional $Z_5$ and $Z_3$ symmetries, one of which can be embedded in $U(1{)}_{B-L}$. Five complex scalar singlet fields are introduced in addition to the standard model with right-handed neutrinos. Although more general, the modified texture of the model retains the successful features of the minimal texture without fine-tuning; namely, it accommodates the masses and mixing of the leptonic sector and relates the emergence of large leptonic mixing angles with the seesaw mechanism. For large deviations of the minimal texture, both quasidegenerate spectrum or inverted hierarchy are allowed for neutrino masses.

We report the results of a study of the exclusive charmless semileptonic decays, $B^0\to {\pi }^{-}{\ell }^{+}\nu$, $B^{+}\to {\pi }^0{\ell }^{+}\nu$, $B^{+}\to \omega {\ell }^{+}\nu$, $B^{+}\to \eta {\ell }^{+}\nu$, and $B^{+}\to {\eta }^{\prime }{\ell }^{+}\nu$ ($\ell =e$ or $\mu$) undertaken with approximately $462\times {10}^6$ $B\overline{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the BABAR detector. The analysis uses events in which the signal $B$ decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions in several bins of $q^2$, the square of the momentum transferred to the lepton-neutrino pair, for $B^0\to {\pi }^{-}{\ell }^{+}\nu$, $B^{+}\to {\pi }^0{\ell }^{+}\nu$, $B^{+}\to \omega {\ell }^{+}\nu$, and $B^{+}\to \eta {\ell }^{+}\nu$. From these distributions, we extract the form-factor shapes $f_{+}(q^2)$ and the total branching fractions $\mathcal{B}(B^0\to {\pi }^{-}{\ell }^{+}\nu )=(1.45\pm {0.04}_{\mathrm{stat}}\pm {0.06}_{\mathrm{syst}})\times {10}^{-4}$ (combined ${\pi }^{-}$ and ${\pi }^0$ decay channels assuming isospin symmetry), $\mathcal{B}(B^{+}\to \omega {\ell }^{+}\nu )=(1.19\pm {0.16}_{\mathrm{stat}}\pm {0.09}_{\mathrm{syst}})\times {10}^{-4}$ and $\mathcal{B}(B^{+}\to \eta {\ell }^{+}\nu )=(0.38\pm {0.05}_{\mathrm{stat}}\pm {0.05}_{\mathrm{syst}})\times {10}^{-4}$. We also measure $\mathcal{B}(B^{+}\to {\eta }^{\prime }{\ell }^{+}\nu )=(0.24\pm {0.08}_{\mathrm{stat}}\pm {0.03}_{\mathrm{syst}})\times {10}^{-4}$. We obtain values for the magnitude of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element $|V_{ub}|$ by direct comparison with three different QCD calculations in restricted $q^2$ ranges of $B\to \pi {\ell }^{+}\nu$ decays. From a simultaneous fit to the experimental data over the full $q^2$ range and the FNAL/MILC lattice QCD predictions, we obtain $|V_{ub}|=(3.25\pm 0.31)\times {10}^{-3}$, where the error is the combined experimental and theoretical uncertainty.

The detection of magnetic fields at high redshifts, and in empty intergalactic space, supports the idea that cosmic magnetism has a primordial origin. Assuming that Maxwellian electromagnetism and general relativity hold, and without introducing any new physics, we show how the observed magnetic fields can easily survive cosmological evolution from the inflationary era in a marginally open Friedmann universe but fail to do so, by a very wide margin, in a flat or a marginally closed universe. Magnetic fields evolve very differently in open and closed Friedmann models. The existence of significant magnetic fields in the universe today, that require primordial seeding, may therefore provide strong evidence that the universe is marginally open rather than marginally closed.

Either by solving the ghost propagator Dyson-Schwinger equations or through a one-loop computation in the refined Gribov-Zwanziger (RGZ) formalism, we show that a nontrivial ghost-gluon vertex is required to obtain a ghost propagator prediction compatible with the available corresponding lattice data in the SU(3) case. For the necessary gluon propagator input, we present RGZ tree-level fits which account well for the gluon lattice data. Interestingly, this propagator can be rewritten in terms of a running gluon mass. A comparison of both Dyson-Schwinger equations and RGZ results for the ghost propagator is furthermore provided. We also briefly discuss the connection between the RGZ and the operator product expansion $d=2$ gluon condensate.

Quantum-corrected equations of motion generically contain higher time derivatives, computed here in the setting of canonically quantized systems. The main example in which detailed derivations are presented is a general anharmonic oscillator, but conclusions can be drawn also for systems in quantum gravity and cosmology.

We demonstrate the presence of genuine multipartite entanglement between the modes of quantum fields in nonuniformly moving cavities. The transformations generated by the cavity motion can be considered as multipartite quantum gates. We present two setups for which multimode entanglement can be generated for bosons and fermions. As a highlight we show that the genuine bosonic multipartite correlations can be resonantly enhanced. Our results provide fundamental insights into the structure of Bogoliubov transformations and suggest strong links between quantum information, quantum fields in curved spacetimes and gravitational analogues by way of the equivalence principle.

The $\mathrm{CP}(N-1)$ $\sigma$ model on finite interval of length $R$ with Dirichlet boundary conditions is analyzed in the $1/N$ expansion. The theory has two phases, separated by a phase transition at $R\sim 1/\Lambda$, and $\Lambda$ is a dynamical scale of the $\mathrm{CP}(N-1)$ model. The vacuum energy dependence of $R$, and especially Casimir-type scaling $1/R$, is discussed.

We prove that the hard thermal loop contribution to static thermal amplitudes can be obtained by setting all the external four-momenta to zero before performing the Matsubara sums and loop integrals. At the one-loop order we do an iterative procedure for all the one-particle irreducible one-loop diagrams, and at the two-loop order we consider the self-energy. Our approach is sufficiently general to the extent that it includes theories with any kind of interaction vertices, such as gravity in the weak field approximation, for $d$ space-time dimensions. This result is valid whenever the external fields are all bosonic.

Considering cylindrical topology, we present the static solution for a charged black hole in conformal gravity. We show that unlike the general relativistic case, there are two different solutions, both including a factor which gives rise to a linear term in the potential, which also features in the neutral case. This may have significant ramifications for particle trajectories.

We study nonspinning $Q$-balls and boson stars in four-dimensional anti-de Sitter (AdS) space-time. We use an exponential scalar field potential that appears in gauge-mediated supersymmetry (SUSY) breaking in the minimal supersymmetric extension of the Standard Model (MSSM). We investigate the dependence of the charge and mass of these nontopological solitons on the negative cosmological constant, the frequency that appears in the periodic time dependence, and the ratio between the SUSY-breaking scale and the Planck mass. Next to fundamental solutions without nodes in the scalar field function, we also construct radially excited solutions. In the second part of the paper we put the emphasis on the holographic interpretation of these solutions in terms of Bose-Einstein condensates of scalar glueballs that are described by a strongly coupled quantum field theory (QFT) on the boundary of global AdS.

The background of gravitational waves produced by the ensemble of rotating neutron stars (which includes pulsars, magnetars, and gravitars) is investigated. A formula for $\Omega (f)$ (a function that is commonly used to quantify the background, and is directly related to its energy density) is derived, without making the usual assumption that each radiating system evolves on a short time scale compared to the Hubble time; the time evolution of the systems since their formation until the present day is properly taken into account. Moreover, the formula allows one to distinguish the different parts of the background: the unresolvable (which forms a stochastic background or confusion noise, since the waveforms composing it cannot be either individually observed or subtracted out of the data of a detector) and the resolvable. Several estimations of the background are obtained, for different assumptions on the parameters that characterize neutron stars and their population. In particular, different initial spin period distributions lead to very different results. For one of the models, with slow initial spins, the detection of the background by present or planned detectors can be rejected. However, other models do predict the detection of the background, that would be unresolvable, by the future ground-based gravitational wave detector ET. A robust upper limit for the background of rotating neutron stars is obtained; it does not exceed the detection threshold of two cross-correlated Advanced LIGO interferometers. If gravitars exist and constitute more than a few percent of the neutron star population, then they produce an unresolvable background that could be detected by ET. Under the most reasonable assumptions on the parameters characterizing a neutron star, the background is too faint to be detected. Previous papers have suggested neutron star models in which large magnetic fields (like the ones that characterize magnetars) induce big deformations in the star, which produce a stronger emission of gravitational radiation. Considering the most optimistic (in terms of the detection of gravitational waves) of these models, an upper limit for the background produced by magnetars is obtained; it could be detected by ET, but not by BBO or DECIGO. Simple approximate formulas to characterize both the total and the unresolvable backgrounds are given for the ensemble of rotating neutron stars, and, for completion, also for the ensemble of binary star systems.

We consider a singlet Dirac fermion with Peccei-Quinn (PQ) symmetry as dark matter. A singlet complex scalar is introduced to mediate between dark matter and the Standard Model through Higgs portal interaction and electroweak PQ anomalies. We show that a resonant annihilation of dark matter with axion mediation can explain the monochromatic photon line of the Fermi Large Area Telescope data at 130 GeV by anomaly interactions while the annihilation cross section with Higgs portal interaction is $p$-wave suppressed. We discuss the interplay between the direct detection of the fermion dark matter and the collider search of Higgs-like scalars. We also present an ultraviolet completion of the dark matter model into the Next-to-Minimal Supersymmetric Standard Model with PQ symmetry.

Some vectorlike quarks are added to the Higgs triplet model with the motivation of fitting the recent Higgs boson data released by LHC and Tevatron collaborations. These vectorlike quarks can suppress the cross section of $gg\to h$ sizably, while the charged scalars, especially for the doubly charged scalar, can enhance $\mathrm{Br}(h\to \gamma \gamma )$ more sizably. Besides, the Higgs couplings to $WW$, $ZZ$, and light fermions can be the same as their standard model (SM) values. Thus, the model will enhance the Higgs production rates into $\gamma \gamma$ and $jj\gamma \gamma$, while those for $W{W}^{*}$, $Z{Z}^{*}$, and $\tau \overline{\tau }$ at the LHC are reduced relative to their SM predictions. The Higgs production rate into $Vb\overline{b}$ at the Tevatron is the same as the SM prediction.

We present an analysis of normal and inverted hierarchical neutrino mass models within the framework of tri-bimaximal mixing. Considering the neutrinos to be quasidegenerate (QDN), we study two different neutrino mass models with mass eigenvalues $(m_1,-m_2,m_3)$ and $(m_1,m_2,m_3)$ for both normal hierarchical and inverted hierarchical cases. Parameterizing the neutrino mass matrix using best-fit oscillation and cosmology data for a QDN scenario, we find the right-handed Majorana mass matrix using the type I seesaw formula for two types of Dirac neutrino mass matrices: charged lepton type and up quark type. Incorporating the presence of the type II seesaw term which arises naturally in generic left-right symmetric models along with the type I term, we compare the predictions for neutrino mass parameters with the experimental values. Within such a framework and incorporating both oscillation as well as cosmology data, we show that a QDN scenario of neutrino masses can still survive in nature with some minor exceptions. A viable extension of the standard model with an Abelian-gauged flavor symmetry is briefly discussed which can give rise to the desired structure of the Dirac and Majorana mass matrices.

We investigate the impact of recent limits from LHC searches for supersymmetry and from direct and indirect searches for dark matter on global Bayesian inferences of the parameter space of the constrained Minimal Supersymmetric Standard Model (CMSSM). In particular we apply recent exclusion limits from the CMS ${\alpha }_T$ analysis of $1.1{\mathrm{fb}}^{-1}$ of integrated luminosity, the current direct detection dark matter limit from XENON100, as well as recent experimental constraints on $\gamma$-ray fluxes from dwarf spheroidal satellite galaxies of the Milky Way from the FermiLAT telescope, in addition to updating values for other non-LHC experimental constraints. We extend the range of scanned parameters to include a significant fraction of the focus point/hyperbolic branch region. While we confirm earlier conclusions that at present LHC limits provide the strongest constraints on the model’s parameters, we also find that when the uncertainties are not treated in an excessively conservative way, the new bounds from dwarf spheroidals have the power to significantly constrain the focus point/hyperbolic branch region. Their effect is then comparable, if not stronger, to that from XENON100. We further analyze the effects of one-year projected sensitivities on a neutrino flux from the Sun in the 86-string $\mathrm{\text{IceCube}}+\mathrm{\text{DeepCore}}$ configuration at the South Pole. We show that data on neutrinos from the Sun, expected for the next few months at IceCube and DeepCore, have the potential to further constrain the same region of parameter space independently of the LHC and can yield additional investigating power for the model.