We propose an effective left-right-right-left model with a parity breaking scale around a few TeV. One of the main achievements of the model is that the mirror fermions as well as the mirror gauge sector simultaneously could be at TeV scale. It is shown that the most dangerous quadratic divergence of the SM Higgs boson involving the top quark in the loop is naturally suppressed, and begins at three loop. The model postpones the fine-tuning of the mass of the SM Higgs boson up to a sufficiently high scale. The model explains the smallness of the neutrino masses whether they are Dirac or Majorana. Furthermore, the strong $CP$ phase is zero in this model.

Using the recent joint results from the ATLAS and CMS collaborations on the Higgs boson, we determine the current status of composite electroweak dynamics models based on the expected scalar sector. Our analysis can be used as a minimal template for a wider class of models between the two limiting cases of composite Goldstone Higgs and Technicolor-like ones. This is possible due to the existence of a unified description, both at the effective and fundamental Lagrangian levels, of models of composite Higgs dynamics where the Higgs boson itself can emerge, depending on the way the electroweak symmetry is embedded, either as a pseudo-Goldstone boson or as a massive excitation of the condensate. In our template, a mass term for the fermions in the fundamental theory acts as a stabilizer of the Higgs potential, without the need for partners of the top quark. We constrain the available parameter space at the effective Lagrangian level. We show that a wide class of models of fundamental composite electroweak dynamics are still compatible with the present constraints. The results are relevant for the ongoing and future searches at the Large Hadron Collider.

A light metastable dark photon decaying into a collimated electron/positron pair can fake a photon, either converted or unconverted, at the LHC. The detailed object identification relies on the specifics of the detector and strategies for the reconstruction. We study the fake rate based on the ATLAS (CMS) detector geometry and show that it can be O(1) with a generic choice of parameters. Especially, the probability of being registered as a photon is angular dependent. Such detector effects can induce bias to measurements on certain properties of new physics. In this paper, we consider the scenario where dark photons in final states are from a heavy resonance decay. Consequently, the detector effects can dramatically affect the results when determining the spin of a resonance. Further, if the decay products from the heavy resonance are one photon and one dark photon, which has a large probability to fake a diphoton event, the resonance is allowed to be a vector. Because of the difference in detectors, the cross sections measured in ATLAS and CMS do not necessarily match. Furthermore, if the diphoton signal is given by the dark photons, the standard model $Z\gamma$ and $ZZ$ final states do not necessarily come with the $\gamma \gamma$ channel, which is a unique signature in our scenario. The issue studied here is relevant also for any future new physics searches with photon(s) in the final state. We discuss possible ways of distinguishing dark photon decay and a real photon in the future.

We study a variation of the Krauss-Nasri-Trodden model with a colored triplet scalar field and a colored singlet scalar field. We discuss the anomaly coming from $b\to s\mu \overline{\mu }$, fit to the muon anomalous magnetic moment and the relic density of the Majorana-type dark matter candidate, and satisfy various constraints such as lepton flavor violations and flavor-changing neutral currents. Also, we discuss the direct constraints from the collider searches and the possibilities of detecting the new fields at the LHC.

We propose a novel general approach to locality of lattice composite fields, which in case of QCD involves locality in both quark and gauge degrees of freedom. The method is applied to gauge operators based on the overlap Dirac matrix elements, showing for the first time their local nature on realistic path-integral backgrounds. The framework entails a method for efficient evaluation of such nonultralocal operators, whose computational cost is volume independent at fixed accuracy, and only grows logarithmically as this accuracy approaches zero. This makes computation of useful operators, such as overlap-based topological density, practical. The key notion underlying these features is that of exponential insensitivity to distant fields, made rigorous by introducing the procedure of statistical regularization. The scales associated with insensitivity property are useful characteristics of nonlocal continuum operators.

We present a lattice study of a Nambu–Jona-Lasinio (NJL) model using Wilson fermions. Four-fermion interactions are a natural part of several extensions of the Standard Model, appearing as a low-energy description of a more fundamental theory. In models of dynamical electroweak symmetry breaking they are used to endow the Standard Model fermions with masses. In infrared conformal models these interaction, when sufficiently strong, can alter the dynamics of the fixed point, turning the theory into a (near) conformal model with desirable features for model building. As a first step toward the nonperturbative study of these models, we study the phase space of the ungauged NJL model.

Parton distribution functions (PDFs) are nonperturbative objects defined by nonlocal light-cone correlations. They cannot be computed directly from QCD. Using a standard lattice QCD approach, it is possible to compute moments of PDFs, which are matrix elements of local operators. Recently, an alternative approach has been proposed, based on the introduction of quasi-parton distribution functions (quasi-PDFs), which are matrix elements of equal-time spatial correlations and hence calculable on the lattice. Quasi-PDFs approach standard PDFs in the limit of very large longitudinal proton momenta $P^z$. This limit is not attainable in lattice simulations, and quasi-PDFs fail to reproduce PDFs at high fractional longitudinal momenta. In this paper, we propose a method to improve the reconstruction of PDFs by combining information from quasi-PDFs and from the Mellin moments of regular PDFs. We test our method using the diquark spectator model for up and down valence distributions of both unpolarized and helicity PDFs. In the future, the method can be used to produce PDFs entirely based on lattice QCD results.

The top-antitop energy asymmetry is a promising observable of the charge asymmetry in jet-associated top-quark pair production at the LHC. We present new predictions of the energy asymmetry in proton-proton collisions at 13 TeV, including QCD corrections at the next-to-leading perturbative order. The effect of QCD corrections on the observable is moderate. With suitable phase-space cuts, the asymmetry can be enhanced at the cost of reducing the cross section. For instance, for a cross section of 1 pb after cuts, we predict an energy asymmetry of $-6.5_{-0.2}^{+0.1}\%$ at the next-to-leading order in QCD. We also investigate scale uncertainties and parton-shower effects, which partially cancel in the normalized asymmetry. Our results provide a sound basis for a measurement of the energy asymmetry at the LHC during run II.

In this paper, we find, within the framework of perturbative QCD, that in deuteron-deuteron scattering Bose-Einstein correlations, due to production of two-parton showers, induce azimuthal angle correlations with three correlation lengths: the size of the deuteron ($R_D$), the proton radius ($R_N$), and the size of the Balitski-Fadin-Kuraev-Lipatov (BFKL) Pomeron, which is closely related to the saturation momentum ($R_c\sim 1/Q_s$). These correlations are independent of the values of rapidities of the produced gluons (long range rapidity correlations) for large rapidities (${\overline{\alpha }}_S|y_1-y_2|\ge 1$) and have no symmetry with respect to $\varphi \to \pi -\varphi$ (${\mathit{p}}_{T1}\to -{\mathit{p}}_{T1}$). Therefore, they give rise to $v_n$ for all values of $n$, not only for even values. The contributions of the correlation lengths $R_D$ and $R_N$ crucially depend on the nonperturbative contributions, and obtaining estimates of their values requires a lot of modeling, while the correlations with $R_c\sim 1/Q_s$ have a perturbative QCD origin and can be estimated in the color glass condensate approach.

We extend our earlier results for the quark helicity evolution at small $x$ [J. High Energy Phys. 01 (2016) 072] to derive the small-$x$ asymptotics of the flavor singlet and flavor nonsinglet quark helicity TMDs and PDFs and of the $g_1$ structure function. In the flavor singlet case we rederive the evolution equations obtained in our previous paper on the subject [J. High Energy Phys. 01 (2016) 072], performing additional cross-checks of our results. In the flavor nonsinglet case we construct new small-$x$ evolution equations by employing the large-$N_c$ limit. All evolution equations resum double-logarithmic powers of ${\alpha }_s{\ln }^2(1/x)$ in the polarization-dependent evolution along with the single-logarithmic powers of ${\alpha }_s\ln (1/x)$ in the unpolarized evolution which includes saturation effects. We solve the linearized flavor nonsinglet equation analytically, obtaining an intercept which agrees with the one calculated earlier by Bartels, Ermolaev and Ryskin [Z. Phys. C 70, 273 (1996)] using the infrared evolution equations. Our numerical solution of the linearized large-$N_c$ evolution equations for the flavor singlet case is presented in the accompanying Letter [Phys. Rev. Lett. 118, 052001 (2017)] and is further discussed here.

We derive the pseudoscalar condensate induced by anomaly and vorticity from the Wigner function for massive fermions in homogeneous electromagnetic fields. It has an anomaly term and a force-vorticity coupling term. As a mass effect, the pseudoscalar condensate is linearly proportional to the fermion mass in small mass expansion. By a generalization to two-flavor and three-flavor cases, the neutral pion and eta meson condensates are calculated from the Wigner function and have anomaly parts as well as force-vorticity parts, in which the anomaly part of the neutral pion condensate is consistent with the previous result. We also discuss the possible observables of the condensates in heavy-ion collisions such as collective flows of neutral pions and eta mesons which may be influenced by the electromagnetic field and vorticity profiles.

Encouraged by the observation of the pentaquark states $P_c^{+}(4380)$ and $P_c^{+}(4450)$, we propose a novel color flux-tube structure, a pentagonal state, for pentaquark states within the framework of a color flux-tube mode involving a five-body confinement potential. Numerical results on the heavy pentaquark states indicate that the states with three color flux-tube structures, diquark, octet, and pentagonal structures, have the closest masses, which can therefore be called QCD isomers, analogous to isomers in chemistry. The pentagonal structure has the lowest energy. The state $P_c^{+}(4380)$ can be described as the compact pentaquark state $uudc\overline{c}$ with the pentagonal structure and $J^P={\frac{3}{2}}^{-}$ in the color flux-tube model. The state $P_c^{+}(4450)$ can not be accommodated into the color flux-tube model. The heavy pentaquark states $uudc\overline{b}$, $uudb\overline{c}$, and $uudb\overline{b}$ are predicted in the color flux-tube model. The five-body confinement potential, based on the color flux-tube picture as a collective degree of freedom, is a dynamical mechanism in the formation of the compact heavy pentaquark states.

In this paper, we study the next-to-leading-order corrections to deeply virtual pion and kaon production in neutrino experiments. We estimate these corrections in the kinematics of the minerva experiment at Fermilab, and find that they are sizable and increase the leading-order cross section by up to a factor of 2. We provide a computational code which can be used for the evaluation of the cross sections, taking into account these corrections and employing various generalized parton distribution models.

The Lorentz and $CPT$ symmetries are not violated at the highest laboratory energies available. However these symmetries may be violated at Planck scale. A particular development is to investigate the breakdown of Lorentz and $CPT$ symmetries by introducing an aether field that exhibits nonzero vacuum expectation value along the fifth dimension. The interactions of the aether field with scalar, electromagnetic, and fermions fields are analyzed. The Stefan-Boltzmann law and Casimir effect at finite temperature are calculated using the Thermo Field Dynamics formalism.

We present a new method for evaluating the response of a moving qubit detector interacting with a scalar field in Minkowski spacetime. We treat the detector as an open quantum system, but we do not invoke the Markov approximation. The evolution equations for the qubit density matrix are valid at all times, for all qubit trajectories, and they incorporate non-Markovian effects. We analyze in detail the case of uniform acceleration, providing a detailed characterization of all regimes where non-Markovian effects are significant. We argue that the most stable characterization of acceleration temperature refers to the late time behavior of the detector because interaction with the field vacuum brings the qubit to a thermal state at the Unruh temperature. In contrast, the early-time transition rate, that is invoked in most discussions of acceleration temperature, does not exhibit a thermal behavior when non-Markovian effects are taken into account. Finally, we note that the non-Markovian evolution derived here also applies to the mathematically equivalent problem of a static qubit interacting with a thermal field bath.

We solve the Hamiltonian and momentum constraints of general relativity for two black holes with nearly extremal spins and relativistic boosts in the puncture formalism. We use a non-conformally-flat ansatz with an attenuated superposition of two Lorentz-boosted, conformally Kerr or conformally Schwarzschild 3-metrics and their corresponding extrinsic curvatures. We compare evolutions of these data with the standard Bowen-York conformally flat ansatz (technically limited to intrinsic spins $\chi =S/M_{\mathrm{ADM}}^2=0.928$ and boosts $P/M_{\mathrm{ADM}}=0.897$), finding, typically, an order of magnitude smaller burst of spurious radiation and agreement with inspiral and merger. As a first case study, we evolve two equal-mass black holes from rest with an initial separation of $d=12M$ and spins ${\chi }_i=S_i/m_i^2=0.99$, compute the waveforms produced by the collision, the energy and angular momentum radiated, and the recoil of the final remnant black hole. We find that the black-hole trajectories curve at close separations, leading to the radiation of angular momentum. We also study orbiting nonspinning and moderate-spin black-hole binaries and compare these with standard Bowen-York data. We find a substantial reduction in the nonphysical initial burst of radiation which leads to cleaner waveforms. Finally, we study the case of orbiting binary black-hole systems with spin magnitude ${\chi }_i=0.95$ in an aligned configuration and compare waveform and final remnant results with those of the SXS Collaboration [A. H. Mroue et al., Phys. Rev. Lett. 111, 241104 (2013).], finding excellent agreement. This represents the first moving puncture evolution of orbiting and spinning black holes exceeding the Bowen-York limit. Finally, we study different choices of the initial lapse and lapse evolution equation in the moving puncture approach to improve the accuracy and efficiency of the simulations.

Results are presented from numerical simulations of the Einstein-Maxwell-Higgs equations with a broken U(1) symmetry. Coherent nontopological soliton solutions are shown to exist that separate an anti–de Sitter (AdS) true vacuum interior from a Reissner-Nordstrom (RN) false vacuum exterior. The stability of these bubble solutions is tested by perturbing the charge of the coherent solution and evolving the time-dependent equations of motion. In the weak gravitational limit, the short-term stability depends on the sign of $(\omega /Q){\partial }_{\omega }Q$, similar to $Q$-balls. The long-term end state of the perturbed solutions demonstrates a rich structure and is visualized using “phase diagrams.” Regions of both stability and instability are shown to exist for ${\kappa }_g\lesssim 0.015$, while solutions with ${\kappa }_g\gtrsim 0.015$ were observed to be entirely unstable. Threshold solutions are shown to demonstrate time-scaling laws, and the space separating true and false vacuum end states is shown to be fractal in nature, similar to oscillons. Coherent states with superextremal charge-to-mass ratios are shown to exist and observed to collapse or expand, depending on the sign of the charge perturbation. Expanding superextremal bubbles induce phase transitions to the true AdS vacuum, while collapsing superextremal bubbles can form nonsingular strongly gravitating solutions with superextremal RN exteriors.

We examine how to construct a spatial manifold and its geometry from the entanglement structure of an abstract quantum state in Hilbert space. Given a decomposition of Hilbert space $\mathcal{H}$ into a tensor product of factors, we consider a class of “redundancy-constrained states” in $\mathcal{H}$ that generalize the area-law behavior for entanglement entropy usually found in condensed-matter systems with gapped local Hamiltonians. Using mutual information to define a distance measure on the graph, we employ classical multidimensional scaling to extract the best-fit spatial dimensionality of the emergent geometry. We then show that entanglement perturbations on such emergent geometries naturally give rise to local modifications of spatial curvature which obey a (spatial) analog of Einstein’s equation. The Hilbert space corresponding to a region of flat space is finite-dimensional and scales as the volume, though the entropy (and the maximum change thereof) scales like the area of the boundary. A version of the $\mathrm{ER}=\mathrm{EPR}$ conjecture is recovered, in that perturbations that entangle distant parts of the emergent geometry generate a configuration that may be considered as a highly quantum wormhole.

Cosmic acceleration may be due to modifications of cosmic gravity and to test this we need robust connections between theory and observations. However, in a model independent approach like effective field theory or a broad class like Horndeski gravity, several free functions of time enter the theory. We show that simple parametrizations of these functions are unlikely to be successful; in particular the approximation ${\alpha }_i(t)\propto {\mathrm{\Omega }}_{\mathrm{de}}(t)$ drastically misestimates the observables. This holds even in simple modified gravity theories like $f(R)$. Indeed, oversimplified approximations to the property functions ${\alpha }_i(t)$ can even miss the signature of modified gravity. We also consider the question of consistency relations and the role of tensor (gravitational wave) perturbations.

We consider a class of flavor models proposed by Aranda, Carone and Lebed, relaxing the assumption of supersymmetry and allowing the flavor scale to float anywhere between the weak and Planck scales. We perform global fits to the charged fermion masses and Cabibbo-Kobayashi-Maskawa angles, and consider the dependence of the results on the unknown mass scale of the flavor sector. We find that the typical Yukawa textures in these models provide a good description of the data over a wide range of flavor scales, with a preference for those that approach the lower bounds allowed by flavor-changing-neutral-current constraints. Nevertheless, the possibility that the flavor scale and Planck scale are identified remains viable. We present models that demonstrate how the assumed textures can arise most simply in a nonsupersymmetric framework.