The double quarkonium production in single and double diffractive processes is investigated considering $pp$ collisions at the Run 2 LHC energy. Using the nonrelativistic QCD factorization formalism for the quarkonium production and the resolved Pomeron model to describe the diffractive processes, we estimate the rapidity and transverse momentum dependencies of the cross sections for the $J/\mathrm{\Psi }J/\mathrm{\Psi }$ and $\mathrm{\Upsilon }\mathrm{\Upsilon }$ production. The contributions of the color-singlet and color-octet channels are estimated, and predictions for the total cross sections in the kinematical regions of the LHC experiments are also presented. Our results demonstrate that the double quarkonium production in diffractive processes is not negligible and that its study can be useful to test the underlying assumptions present in the description of the single and double diffractive processes.

In the present paper, the ATLAS inclusive $W^{\pm }$ and $Z$ boson production data are analyzed together with the CMS inclusive $W^{\pm }$ and $Z$ boson production data to investigate any possible tensions between the data sets and to determine the strange sea fraction, within the framework of a parton distribution function fit at next-to next-to-leading order in perturbative QCD.

The Yukawa model in curved spacetime is considered. We consider a complex scalar field coupled to a $U(1)$ gauge field and also interacting with Dirac fields with a general Yukawa coupling. The local momentum space method is used to obtain the one-loop effective action, and we adopt the gauge condition independent background field method introduced by Vilkovisky and DeWitt. The pole parts of the one-loop effective action that depend on the background scalar field, that we do not assume to be constant, are found and used to calculate the counterterms and to determine the relevant renormalization group functions. Terms in the effective action that involve the gradient terms in the scalar field as well as the effective potential are found in the case where the scalar field and Dirac fields are massless. We also discuss the anomaly that arises if the pseudoscalar mass term for the Dirac fermions is removed by a chiral transformation.

Relativistic quantum mechanics of a Proca (spin-1) particle in Riemannian spacetimes is constructed. Covariant equations defining electromagnetic interactions of a Proca particle with the anomalous magnetic moment and the electric dipole moment in Riemannian spacetimes are formulated. The relativistic Foldy-Wouthuysen transformation with allowance for terms proportional to the zero power of the Planck constant is performed. The Hamiltonian obtained agrees with the corresponding Foldy-Wouthuysen Hamiltonians derived for scalar and Dirac particles and with their classical counterpart. The unification of relativistic quantum mechanics in the Foldy-Wouthuysen representation is discussed.

We study the creation of a spherical, finite radius source for a quantized massless scalar field in $3+1$ dimensions. The goal is to model the breakdown of correlations that has been proposed to occur at the horizon of an evaporating black hole. We do this by introducing at fixed radius $r=a$ a one parameter family of self-adjoint extensions of the three dimensional Laplacian operator that interpolate between the condition that the values and the derivatives on the two sides of $r=a$ coincide for $t\le 0$ (no wall) and the two-sided Dirichlet boundary condition for $t\ge 1/\lambda$ (fully-developed wall). Creation of the shell produces null, spherical pulses of energy on either side of the shell, one ingoing and the other outgoing. The renormalized energy density $⟨T_{00}⟩$ diverges to positive infinity in the outgoing energy pulse, just outside the light cone of the fully-formed wall at $t=1/\lambda$. Unlike in the $3+1$ point source creation, there is no persistent memory cloud of energy. As in the creation of a $1+1$ dimensional wall, the response of an Unruh-DeWitt detector in the post-shell region is independent of the time scale for shell formation and is finite. The latter property casts doubt on the efficacy of this mechanism for firewall creation.

We present a complete formulation of the scalar bispectrum in the unified effective field theory (EFT) of inflation, which includes the Horndeski and beyond-Horndeski Gleyzes-Langlois-Piazza-Vernizzi classes, in terms of a set of simple one-dimensional integrals. These generalized slow-roll expressions remain valid even when slow-roll is transiently violated, and encompass all configurations of the bispectrum. We show analytically that our expressions explicitly preserve the squeezed-limit consistency relation beyond slow-roll. As an example application of our results, we compute the scalar bispectrum in a model in which potential-driven G-inflation at early times transitions to chaotic inflation at late times, showing that our expressions accurately track the bispectrum when slow-roll is violated and conventional slow-roll approximations fail.

We consider the world-sheet S matrix of superstrings on an ${\mathrm{AdS}}_3\times {\mathrm{S}}^3\times {\mathrm{T}}^4$ NS-NS background in uniform light-cone gauge. We argue that scattering is given by a CDD factor that is nontrivial only between opposite-chirality particles, yielding a spin-chain-like Bethe ansatz. Our proposal reproduces the spectrum of nonprotected states computed from the Wess-Zumino-Witten description and the perturbative tree-level S matrix. This suggests that the model is an integrable deformation of a free theory similar to those arising from the $T\overline{T}$ composite operator.

We revisit the instanton-dyon liquid model in the confined phase by using a nonlinear Debye-Huckel (DH) resummation for the Coulomb interactions induced by the moduli, followed by a cluster expansion. The organization is shown to rapidly converge and yields center symmetry at high density. The dependence of these results on a finite vacuum angle is also discussed. We also formulate the hypernetted chain (HNC) resummation for the dense instanton-dyon liquid and use it to estimate the liquid pair correlation functions in the DH limit. At very low temperature, the dense limit interpolates between chains and rings of instanton–anti-instanton dyons and a bcc crystal, with strong topological and magnetic correlations.

In the Standard Model, the Higgs boson is a $CP$-even state with $CP$-conserving couplings; any deviations from this would be a sign of new physics. These $CP$ properties can be probed by measuring Higgs decays to $\tau$ lepton pairs, in which the transverse correlation between the $\tau$ spins depends on $CP$. This paper develops such an analysis, using full simulation of signal and background events in the International Large Detector concept for the International Linear Collider. We consider Higgs-strahlung events (${\mathit{e}}^{+}{\mathit{e}}^{-}\to \mathit{HZ}$) in which the $Z$ boson decays to electrons, muons, or hadrons, and the Higgs boson decays to $\tau$ leptons, which then decay either to ${\tau }^{\pm }\to {\pi }^{\pm }\nu$ or ${\tau }^{\pm }\to {\pi }^{\pm }{\pi }^0\nu$. Assuming $2{\mathrm{ab}}^{-1}$ of integrated luminosity at a center-of-mass energy of 250 GeV, the mixing angle between even and odd $CP$ components of the $\tau$ pair from Higgs boson decays can be measured to a precision of 75 mrad (4.3°).

We revisit the extraction of the triple electroweak gauge boson couplings from the Large Hadron Collider Run I data on the $W^{+}{W}^{-}$ and $W^{\pm }Z$ productions when the analysis also contains additional operators that modify the couplings of the gauge bosons to light quarks and the gauge boson self-energies. We work in the framework of effective Lagrangians where we consider dimension-six operators and perform a global fit to consistently take into account the bounds on these additional operators originating from the electroweak precision data. We show that the constraints on the Wilson coefficients $f_B/{\mathrm{\Lambda }}^2$ and $f_W/{\mathrm{\Lambda }}^2$ are modified when we include the additional operators while the limits on $f_{WWW}/{\mathrm{\Lambda }}^2$ remain unchanged.

We propose an algorithm of extracting Schrödinger theories under all viable physical time from the Einstein-Hilbert path integral, formulated as the timeless transition amplitudes $\widehat{\mathbb{P}}:\mathbb{K}\to {\mathbb{K}}^{*}$ between the boundary states in a kinematic Hilbert space $\mathbb{K}$. Each of these Schrödinger theories refers to a certain set of quantum degrees of freedom in $\mathbb{K}$ as a background, with their given values specifying moments of the physical time. Restricted to these specified background values, the relevant elements of $\widehat{\mathbb{P}}$ are transformed by the algorithm into the unitary propagator of a corresponding reduced phase space Schrödinger theory. The algorithm embodies the fundamental principle of quantum Cauchy surfaces, such that all the derived Schrödinger theories emerge from one timeless canonical theory defined by $\widehat{\mathbb{P}}$ as a rigging map, via the relational Dirac observables referring to the corresponding backgrounds. We demonstrate its application to a Friedmann-Robertson-Walker loop quantum cosmology (FRW loop quantum cosmology) model with a massless Klein-Gordon scalar field. Recovering the famous singularity-free quantum gravitational dynamics with the background of the scalar field, we also obtain in another reference frame a modified Klein-Gordon field quantum dynamics with the background of the spatial (quantum) geometry.

Black holes in Lorentz-violating theories have been claimed to violate the second law of thermodynamics by perpetual motion energy extraction. We revisit this question for a Penrose splitting process in a spherically symmetric setting with two species of particles that move on radial geodesics that extend to infinity. We show that energy extraction by this process cannot happen in any theory in which gravity is attractive, in the sense of a geometric inequality that we describe. This inequality is satisfied by all known Einstein-æther and Hořava black hole solutions.

It is known that if the Peccei-Quinn symmetry-breaking field is displaced from its minimum during inflation, the axion isocurvature spectrum is generically strongly blue tilted with a break transition to a flat spectrum. We fit this spectrum (incorporated into the “vanilla” $\mathrm{\Lambda }\text{−}\mathrm{CDM}$ cosmological model) to the Planck and BOSS DR11 data to assess how much the existing data can accommodate the presence of axionic blue-tilted isocurvature perturbations. We find that the preferred parameter region is consistent with all of the dark matter being composed of QCD axions in the context of inflationary cosmology with an expansion rate of order $10^8\mathrm{GeV}$, the axion decay constant of order $10^{13}\mathrm{GeV}$, and the initial misalignment angle of order unity. The data are consistent with there being no isocurvature perturbations at the level of just above one sigma. Intriguingly, isocurvature with a spectral break may at least partially explain the low-$\ell$ vs high-$\ell$ anomalies seen in the CMB data.

We investigate the possibility of addressing inflation, a strongly first-order electroweak phase transition (SFOEWPT) together with the dark matter (DM) explanation simultaneously. We study the Higgs-portal real scalar singlet model and the complex scalar singlet model. In both models, the SFOEWPT can occur through two-step patterns in which the magnitude of the Higgs-singlet quartic couplings meets the slow-roll condition of inflation. The Higgs-portal real scalar singlet model cannot address the correct DM relic density together with the explanation of inflation and SFOEWPT. Taking advantage of the cancellation in the DM-nucleon interaction, the weakly interacting massive particles DM can saturate the correct DM relic abundance in the complex scalar singlet model, with the pseudoscalar being the DM candidate after the global U(1) symmetry is broken. The key ingredient in obtaining the successful inflation and the SFOEWPT is that the magnitude of the scalar quartic couplings should be relatively lower. Because the cancellation of the DM-nucleon scattering amplitude mediated by mixtures of SM Higgs and other heavy scalars can occur to a different extent in many models, we can expect that the features being explored here are general.

We investigate the splashback features of dark-matter halos based on cosmic density and velocity fields. Besides the density correlation function binned by the halo orientation angle, which was used in the literature, we introduce, for the first time, the corresponding velocity statistic, alignment momentum correlation function, to take into account the asphericity of halos. Using large-volume, high-resolution $N$-body simulations, we measure the alignment statistics of density and velocity. On halo scales, $x\sim R_{200\mathrm{m}}\sim 1h^{-1}\mathrm{Mpc}$, we detect a sharp steepening in the momentum correlation associated with the physical halo boundary, or the splashback feature, which is found more prominent than in the density correlation. We also find that the splashback radius determined from the density correlation becomes $\sim 3.5\%$ smaller than that from the momentum correlation, with their correlation coefficient being 0.605. Moreover, the orientation-dependent splashback feature due to halo asphericity is measured when the density profile is determined by dark-matter particles, which can be used as a test of collisional cold dark matter since the halo shape is predicted to be rounder in such a model.

We introduce the Generalised Lensing and Shear Spectra (GLaSS) code which is available for download from https://github.com/astro-informatics/GLaSS It is a fast and flexible public code, written in Python, that computes generalized spherical cosmic shear spectra. The commonly used tomographic and spherical Bessel lensing spectra come as built-in run-mode options. GLaSS is integrated into the Cosmosis modular cosmological pipeline package. We outline several computational choices that accelerate the computation of cosmic shear power spectra. Using GLaSS, we test whether the assumption that using the lensing and projection kernels for a spatially-flat universe—in a universe with a small amount of spatial curvature—negligibly impacts the lensing spectrum. We refer to this assumption as the spatially-flat universe approximation, that has been implicitly assumed in all cosmic shear studies to date. We confirm that the spatially-flat universe approximation has a negligible impact on Stage IV cosmic shear experiments.

Weakly interacting massive particles (WIMPs) have long reigned as one of the leading classes of dark matter candidates. The observed dark matter abundance can be naturally obtained by freezeout of weak-scale dark matter annihilations in the early Universe. This “thermal WIMP” scenario makes direct predictions for the total annihilation cross section that can be tested in present-day experiments. While the dark matter mass constraint can be as high as $m_{\chi }\gtrsim 100\mathrm{GeV}$ for particular annihilation channels, the constraint on the total cross section has not been determined. We construct the first model-independent limit on the WIMP total annihilation cross section, showing that allowed combinations of the annihilation-channel branching ratios considerably weaken the sensitivity. For thermal WIMPs with $s$-wave $2\to 2$ annihilation to visible final states, we find the dark matter mass is only known to be $m_{\chi }\gtrsim 20\mathrm{GeV}$. This is the strongest largely model-independent lower limit on the mass of thermal-relic WIMPs; together with the upper limit on the mass from the unitarity bound ($m_{\chi }\lesssim 100\mathrm{TeV}$), it defines what we call the “WIMP window.” To probe the remaining mass range, we outline ways forward.

In the Milky Way galaxy, positrons, which are responsible for the diffuse 511 keV gamma ray emission observed by space-based gamma ray observatories, are thought to annihilate predominantly through charge exchange interactions with neutral hydrogen. These charge exchange interactions can only take place if positrons have energies greater than 6.8 eV, the minimum energy required to liberate the electron bound to the hydrogen atom and then form positronium, a short-lived bound state composed of a positron-electron pair. Here we demonstrate the importance of positron interactions with neutral alkali metals in the warm interstellar medium (ISM). Positrons may undergo charge exchange with these atoms at any energy. In particular, we show that including positron interactions with sodium at solar abundance in the warm ISM can significantly reduce the annihilation timescale of positrons with energies below 6.8 eV by at least an order of magnitude. We show that including these interactions in our understanding of positron annihilation in the Milky Way rules out the idea that the number of positrons in the Galactic ISM could be maintained in steady state by injection events occurring at a typical periodicity $>\mathrm{Myr}$.

The open-charm strong decays of higher charmonium states up to the mass of the $6P$ multiplet are systematically studied in the ${}^3{P}_0$ model. The wave functions of the initial charmonium states are calculated in the linear potential and screened potential quark models. The decay widths for most of the well-established charmonium states above the open-charm thresholds can be reasonably described. By comparing our quark model calculations with the experimental observations we also discuss the nature of some of the newly observed charmonium-like states. It is found that (i) the $\psi (4415)$ may favor the $\psi (4S)$ or ${\psi }_1(3D)$ assignment. There may exist two highly overlapping vector charmonium states around 4.4 GeV; (ii) in the LP model the $J^{PC}=1^{--}$ $Y(4660)$ resonance and the $J^{PC}=0^{++}$ $X(4500)$ resonance may be assigned as the $\psi (5S)$ and ${\chi }_{c0}(4P)$, respectively; (iii) the newly observed state $X^{*}(3860)$ can be assigned as the ${\chi }_{c0}(2P)$ state with a narrow width of about 30 MeV; (iv) it seems to be difficult to accommodate the $X(4140)$ and $X(4274)$ states in the same potential model as excited ${\chi }_{c1}$ states; (v) the $X(3940)$ resonance can be assigned as the ${\eta }_c(3S)$ state; (vi) the vector charmonium-like states $Y(4230/4260,4360)$ and scalar $X(4700)$ cannot be described by any conventional charmonium states self-consistently in our model.