Within the framework of the $B$-meson light-cone sum rules, we review the calculation of radiative corrections to the three $B\to \pi$ transition form factors at leading power in $\mathrm{\Lambda }/m_b$. To resum large logarithmic terms, we perform the complete renormalization group evolution of the correlation function. We employ the integral transformation which diagonalizes evolution equations of the jet function and the $B$-meson light-cone distribution amplitude to solve these evolution equations and obtain renormalization group improved sum rules for the $B\to \pi$ form factors. Results of the form factors are extrapolated to the whole physical $q^2$ region and are compared with that of other approaches. The effect of $B$-meson three-particle light-cone distribution amplitudes, which will contribute to the form factors at next-to-leading power in $\mathrm{\Lambda }/m_b$ at tree level, is not considered in this paper.

We study single spin asymmetries at one-loop accuracy in semi-inclusive DIS with a transversely polarized hadron in the initial state. Two measurable spin observables are predicted in the framework of QCD collinear factorization. One of the spin observables is the Sivers weighted asymmetry; another one is the Collins weighted asymmetry. The prediction takes a form of convolutions of perturbative coefficient functions and nonperturbative functions, which are twist-2 transversity distributions, twist-3 parton distributions, and twist-2 and twist-3 parton fragmentation functions. These nonperturbative functions can be extracted from measurements of the spin observables and provide valuable information of the inner structure of hadrons. The measurements can be done in current COMPASS and JLab experiments and in future experiments of EIC. The perturbative coefficient functions are calculated at the one-loop level. There are collinear divergences in the calculation involving chirality-even and chirality-odd twist operators. We find that all collinear divergences can be correctly subtracted so that the final results are finite.

The decay $J/\psi \to \gamma \gamma \varphi$ is studied using a sample of $1.31\times {10}^{9}J/\psi$ events collected with the BESIII detector. Two structures around $1475\mathrm{MeV}/c^2$ and $1835\mathrm{MeV}/c^2$ are observed in the $\gamma \varphi$ invariant mass spectrum for the first time. With a fit on the $\gamma \varphi$ invariant mass, which takes into account the interference between the two structures, and a simple analysis of the angular distribution, the structure around $1475\mathrm{MeV}/c^2$ is found to favor an assignment as the $\eta (1475)$ and the mass and width for the structure around $1835\mathrm{MeV}/c^2$ are consistent with the $X(1835)$. The statistical significances of the two structures are $13.5\sigma$ and $6.3\sigma$, respectively. The results indicate that both $\eta (1475)$ and $X(1835)$ contain a sizeable $s\overline{s}$ component.

The time evolution of entanglement tracks how information propagates in interacting quantum systems. We study entanglement entropy in ${\mathrm{CFT}}_2$ with a time-dependent Hamiltonian. We perturb by operators with time-dependent source functions and use the replica trick to calculate higher-order corrections to entanglement entropy. At first order, we compute the correction due to a metric perturbation in ${\mathrm{AdS}}_3/{\mathrm{CFT}}_2$ and find agreement on both sides of the duality. Past first order, we find evidence of a universal structure of entanglement propagation to all orders. The central feature is that interactions entangle unentangled excitations. Entanglement propagates according to “entanglement diagrams,” proposed structures that are motivated by accessory spacetime diagrams for real-time perturbation theory. To illustrate the mechanisms involved, we compute higher-order corrections to free fermion entanglement entropy. We identify an unentangled operator, one which does not change the entanglement entropy to any order. Then, we introduce an interaction and find it changes entanglement entropy by entangling the unentangled excitations. The entanglement propagates in line with our conjecture. We compute several entanglement diagrams. We provide tools to simplify the computation of loop entanglement diagrams, which probe UV effects in entanglement propagation in CFT and holography.

A symmetry of Brans-Dicke gravity in (electro)vacuo or in the presence of conformally invariant matter is presented and used as a solution-generating technique starting from a known solution as a seed. This novel technique is applied to generate, as examples, new spatially homogeneous and isotropic cosmologies, a 3-parameter family of spherical time-dependent spacetimes conformal to a Campanelli-Lousto geometry, and a family of cylindrically symmetric geometries.

It was shown that the dark matter (DM) minihalo around an intermediate mass black hole (IMBH) can be redistributed into a cusp, called the DM minispike. We consider an intermediate-mass-ratio inspiral consisting of an IMBH harbored in a DM minispike with nonannihilating DM particles and a small black hole (BH) orbiting around it. We investigate gravitational waves (GWs) produced by this system and analyze the waveforms with the comprehensive consideration of gravitational pull, dynamical friction and accretion of the minispike and calculate the time difference and phase difference caused by it. We find that for a certain range of frequency, the inspiralling time of the system is dramatically reduced for smaller central IMBH and large density of DM. For the central IMBH with ${10}^5{M}_{\odot }$, the time of merger is ahead, which can be distinguished by LISA, Taiji and Tianqin. We focus on the effect of accretion and compare it with that of gravitational pull and friction. We find that the accretion mass is a small quantity compared to the initial mass of the small BH and the accretion effect is inconspicuous compared with friction. However, the accumulated phase shift caused by accretion is large enough to be detected by LISA, Taiji, and Tianqin, which indicate that the accretion effect can not be ignored in the detection of GWs.

We present the first set of numerical relativity simulations of binary neutron mergers that include spin precession effects and are evolved with multiple resolutions. Our simulations employ consistent initial data in general relativity with different spin configurations and dimensionless spin magnitudes $\sim 0.1$. They start at a gravitational-wave frequency of $\sim 392\mathrm{Hz}$ and cover more than 1 precession period and about 15 orbits up to merger. We discuss the spin precession dynamics by analyzing coordinate trajectories, quasilocal spin measurements, and energetics, by comparing spin aligned, antialigned, and irrotational configurations. Gravitational waveforms from different spin configuration are compared by calculating the mismatch between pairs of waveforms in the late inspiral. We find that precession effects are not distinguishable from nonprecessing configurations with aligned spins for approximately face-on binaries, while the latter are distinguishable from nonspinning configurations. Spin precession effects are instead clearly visible for approximately edge-on binaries. For the parameters considered here, precession does not significantly affect the characteristic postmerger gravitational-wave frequencies nor the mass ejection. Our results pave the way for the modeling of spin precession effects in the gravitational waveform from binary neutron star events.

In this paper, we shall consider an exponential inflationary model in the context of vacuum $F(R)$ gravity. By using well-known reconstruction techniques, we shall investigate which $F(R)$ gravity can realize the exponential inflation scenario at leading order in terms of the scalar curvature, and we shall calculate the slow-roll indices and the corresponding observational indices, in the context of slow-roll inflation. We also provide some general formulas of the slow-roll and the corresponding observational indices in terms of the $e$-foldings number. In addition, for the calculation of the slow-roll and of the observational indices, we shall consider quite general formulas, for which it is not necessary for the assumption that all the slow-roll indices are much smaller than unity to hold true. Finally, we investigate the phenomenological viability of the model by comparing it with the latest Planck and BICEP2/Keck-Array observational data. As we demonstrate, the model is compatible with the current observational data for a wide range of the free parameters of the model.

We present constraints on the patchy reionization by measuring the trispectrum of the Planck 2015 cosmic microwave background (CMB) temperature anisotropies. The patchy reionization leads to anisotropies in the CMB optical depth, and the statistics of the observed CMB anisotropies is altered. We estimate the trispectrum of the CMB temperature anisotropies to constrain spatial variation of the optical depth. We show that the measured trispectrum is consistent with that from the standard lensed CMB simulation at $2\sigma$. While no evidence of the patchy reionization is found in the Planck 2015 temperature trispectrum, the CMB constraint on the patchy reionization is significantly improved from previous works. Assuming the analytic bubble-halo model of Wang and Hu (2006), the constraint obtained in this work rules out the typical bubble size at the ionization fraction of $\sim 0.5$ as $R\gtrsim 10\mathrm{Mpc}$. Further, our constraint implies that large-scale $B$-modes from the patchy reionization are not a significant contamination in detecting the primordial gravitational waves of $r\gtrsim 0.001$ if the $B$ mode induced by the patchy reionization is described by Dvorkin et al. (2009). The CMB trispectrum data starts to provide meaningful constraints on the patchy reionization.

We study observational consequences arising from dark matter (DM) of nonthermal origin, produced by dark freeze-out from a hidden sector heat bath. We assume this heat bath was populated by feebly coupled mediator particles, produced via a Higgs portal interaction with the Standard Model (SM). The dark sector then attained internal equilibrium with a characteristic temperature different from the SM photon temperature. We find that even if the coupling between the DM and the SM sectors is very weak, the scenario allows for indirect observational signals. We show how the expected strength of these signals depends on the temperature of the hidden sector at DM freeze-out.

Two of the most powerful methods currently used to determine the angle $\gamma$ of the CKM Unitarity Triangle exploit $B^{+}\to D{K}^{+}$, $D\to K_S^0{\pi }^{+}{\pi }^{-}$ decays and $B^0\to D{K}^{+}{\pi }^{-}$, $D\to K^{+}{K}^{-}$, ${\pi }^{+}{\pi }^{-}$ decays. It is possible to combine the strengths of both approaches in a “double Dalitz plot” analysis of $B^0\to D{K}^{+}{\pi }^{-}$, $D\to K_S^0{\pi }^{+}{\pi }^{-}$ decays. The potential sensitivity of such an analysis is investigated in the light of recently published experimental information on the $B^0\to D{K}^{+}{\pi }^{-}$ decay. The formalism is also expanded, compared to previous discussions in the literature, to allow $B^0\to D{K}^{+}{\pi }^{-}$ with any subsequent $D$ decay to be included.

We have computed the isospin and spin averaged cross sections of the processes $\pi K^{*}\to \rho K$ and $\rho K^{*}\to \pi K$, which are crucial in the determination of the abundances of $K^{*}$ and $K$ in heavy ion collisions. Improving previous calculations, we have considered several mechanisms which were missing, such as the exchange of axial and vector resonances ($K_1(1270)$, $K_2^{*}(1430)$, $h_1(1170)$, etc…) and also other processes such as $\pi K^{*}\to \omega K,\varphi K$ and $\omega K^{*},\varphi K^{*}\to \pi K$. We find that some of these mechanisms give important contributions to the cross section.

Axionlike particles are promising candidates to make up the dark matter of the Universe, but it is challenging to design experiments that can detect them over their entire allowed mass range. Dark matter in general, and, in particular, axionlike particles and hidden photons, can be as light as roughly ${10}^{-22}\mathrm{eV}$ ($\sim {10}^{-8}\mathrm{Hz}$), with astrophysical anomalies providing motivation for the lightest masses (“fuzzy dark matter”). We propose experimental techniques for direct detection of axionlike dark matter in the mass range from roughly ${10}^{-13}\mathrm{eV}$ ($\sim {10}^2\mathrm{Hz}$) down to the lowest possible masses. In this range, these axionlike particles act as a time-oscillating magnetic field coupling only to spin, inducing effects such as a time-oscillating torque and periodic variations in the spin-precession frequency with the frequency and direction of these effects set by the axion field. We describe how these signals can be measured using existing experimental technology, including torsion pendulums, atomic magnetometers, and atom interferometry. These experiments demonstrate a strong discovery capability, with future iterations of these experiments capable of pushing several orders of magnitude past current astrophysical bounds.

We study the production of heavy sterile neutrino $N$, $e^{+}{e}^{-}\to N\nu (\overline{\nu })$, at the Circular Electron Positron Collider (CEPC) and its $ljj$ signal in its decay to three charged fermions. We study background events for this process which are mainly events coming from W pair production. We study the production of a single heavy sterile neutrino and the sensitivity of CEPC to the mixing of the sterile neutrino with active neutrinos. We study the production of two degenerate heavy sterile neutrinos in a low energy seesaw model by taking into account the constraints on mixings of sterile neutrinos from the neutrinoless double $\beta$ decay experiment and the masses and mixings of active neutrinos. We show that CEPC under proposal has a good sensitivity to the mixing of sterile neutrinos with active neutrinos for a mass of a sterile neutrino around 100 GeV.

We investigate the possibility of using neutrino trident production to probe leptophilic charged scalars at future high intensity neutrino experiments. We show that under specific assumptions, this production process can provide competitive sensitivity for generic charged scalars as compared to common existing bounds. We also investigate how the recently proposed mixed-flavor production—where the two oppositely charged leptons in the final state need not be muon flavored—can give a 20%–50% increase in sensitivity for certain configurations of new physics couplings as compared to traditional trident modes. We then categorize all renormalizable leptophilic scalar extensions based on their representation under $\mathrm{SU}(2)\times \mathrm{U}(1)$, and discuss the Higgs triplet and Zee-Babu models as explicit UV realizations. We find that the inclusion of additional doubly charged scalars and the need to reproduce neutrino masses make trident production uncompetitive with current bounds for these specific UV completions. Our work represents the first application of neutrino trident production to study charged scalars. Additionally, it is the first application of mixed-flavor trident production to study physics beyond the standard model more generally.

We investigate the production of heavy colored scalars and vectors and their relevance at the LHC for the study of vectorlike quarks ($T$). These colored states ($C$) are present in a large number of extensions of the standard model, in particular, in composite models and in extradimensional models. Assuming that these bosonic states are heavier than the vectorlike quarks (VLQ), we consider their production through the process $pp\to C\to tT$. Large QCD production cross sections for $C$ enable us to probe heavier masses for the VLQ, thereby allowing us to put stronger limits on the vectorlike quarks which are produced in their decay chain. We adopt a universal analysis strategy by including leptons under the classification of “jets,” thereby limiting the bias towards a specific combination of final state. We also study the possibility of disentangling these scenarios from supersymmetric extensions of the standard model by using simple discriminants based on jet multiplicity and missing energy. We demonstrate that a simple set of cuts is sufficient to disentangle the VLQ signal from the backgrounds. In models with a moderate $B.R.(C\to Tt)$, the analysis enables one to get a hint of VLQ masses as heavy as 3 TeV.

We study the two-dimensional lattice Thirring model in the presence of a fermion chemical potential. Our model is asymptotically free and contains massive fermions that mimic a baryon and light bosons that mimic pions. Hence, it is a useful toy model for QCD, especially since it, too, suffers from a sign problem in the auxiliary field formulation in the presence of a fermion chemical potential. In this work, we formulate the model in both the world line and fermion-bag representations and show that the sign problem can be completely eliminated with open boundary conditions when the fermions are massless. Hence, we are able accurately compute a variety of interesting quantities in the model, and these results could provide benchmarks for other methods that are being developed to solve the sign problem in QCD.

In this paper, we systematically calculate two-body strong decays of newly observed $D_J(3000)$ and $D_{sJ}(3040)$ with $2\mathrm{P}(1^{+})$ and $2\mathrm{P}(1^{+\prime })$ assignments in an instantaneous approximation of the Bethe-Salpeter equation method. Our results show that both resonances can be explained as the $2\mathrm{P}(1^{{+}^{\prime }})$ with broad width via ${}^3{P}_1$ and ${}^1{P}_1$ mixing in $D$ and $D_s$ families. For $D_J(3000)$, the total width is 229.6 MeV in our calculation, close to the upper limit of experimental data, and the dominant decay channels are $D_2^{*}\pi$, $D^{*}\pi$, and $D^{*}(2600)\pi$. For $D_{sJ}(3040)$, the total width is 157.4 MeV in our calculation, close to the lower limit of experimental data, and the dominant channels are $D^{*}K$ and $D^{*}{K}^{*}$. These results are consistent with observed channels in experiments. Given the very little information that has been obtained from experiments and the large error bars of the total decay widths, we recommend the detection of dominant channels in our calculation.

The structure, spectroscopic parameters and width of the resonance with quantum numbers $J^{PC}=1^{++}$ discovered by the COMPASS Collaboration and classified as the $a_1(1420)$ meson are examined in the context of QCD sum rule method. In the calculations the axial-vector meson $a_1(1420)$ is treated as a four-quark state with the diquark-antidiquark structure. The mass and current coupling of $a_1(1420)$ are evaluated using QCD two-point sum rule approach. Its observed decay mode $a_1(1420)\to f_0(980)\pi$, and kinematically allowed ones, namely $a_1\to K^{*\pm }{K}^{\mp }$, $a_1\to K^{*0}{\overline{K}}^0$ and $a_1\to {\overline{K}}^{*0}{K}^0$ channels are studied employing QCD sum rules on the light-cone. Our prediction for the mass of the $a_1(1420)$ state $m_{a_1}={1416}_{-79}^{+81}\mathrm{MeV}$ is in excellent agreement with the experimental result. Width of this state $\mathrm{\Gamma }=145.52\pm 20.79\mathrm{MeV}$ within theoretical and experimental errors is also in accord with the COMPASS data.

While the postulate of covariance of Maxwell’s equations for all inertial observers led Einstein to special relativity, it was the further demand of general covariance—form invariance under general coordinate transformations, including between accelerating frames—that led to general relativity. Several lines of inquiry over the past two decades, notably the development of metamaterial-based transformation optics, has spurred a greater interest in the role of geometry and space-time covariance for electrodynamics in ponderable media. I develop a generally covariant, coordinate-free framework for electrodynamics in general dielectric media residing in curved background space-times. In particular, I derive a relation for the spatial medium parameters measured by an arbitrary timelike observer. In terms of those medium parameters I derive an explicit expression for the pseudo-Finslerian optical metric of birefringent media and show how it reduces to a pseudo-Riemannian optical metric for nonbirefringent media. This formulation provides a basis for a unified approach to ray and congruence tracing through media in curved space-times that may smoothly vary among positively refracting, negatively refracting, and vacuum.