In this paper we show that ${\beta }_{*}^{\prime }$, the $\beta$-function slopes in the electric and magnetic theories, are equal at the corresponding infrared fixed points. This follows from the scaling of the correlators of the trace of the energy momentum tensors. The slopes ${\beta }_{*}^{\prime }$ determine the scaling dimensions. Our paper can be considered as a commentary to D. Anselmi, M. T. Grisaru, and A. Johansen [Nucl. Phys. B491, 221 (1997)]; it proposes an improved derivation not based on a rather contrived construction by D. Kutasov [Phys. Lett. B 351, 230 (1995)], D. Kutasov and A. Schwimmer [Phys. Lett. B 354, 315 (1995)], and D. Kutasov, A. Schwimmer, and N. Seiberg, [Nucl. Phys. B459, 455 (1996)]. As a byproduct we note that ${\gamma }_{Q^{*}}^{\prime }$—the slopes of the matter superfield anomalous dimension—vanish at both edges of the conformal window where one of the dual theories is strongly coupled. Finally, we determine the two-coupling magnetic fixed point at weak coupling correcting the result of I. I. Kogan, M. A. Shifman, and A. I. Vainshtein [Phys. Rev. D 53, 4526 (1996); Phys. Rev. D59, 109903(E) (1999)].

Motivated by the anisotropic momentum distribution of particles in heavy-ion collisions, we study the angular dependence of quark average momentum and quark distribution function in the Polyakov-Nambu-Jona-Lasinio quark model. We also investigate the phase transitions and net baryon number fluctuations in anisotropic quark matter. The numerical results suggest that the QCD phase structure and isentropic trajectories are sensitive to the anisotropic parameter at finite density, in particular, in the area near the critical region and the first-order phase transition. Compared with the isotropic quark matter, the values of baryon number kurtosis and skewness at lower collision energies are possibly enhanced with the anisotropic momentum distribution squeezed along the direction of nucleus-nucleus collision in experiments.

The measurements of the Cabibbo-Kobayashi-Maskawa (CKM) elements can be contaminated by new-physics effects. We point out that purely leptonic operators at the high scale can influence semileptonic $K$ decays and nuclear beta decay through renormalization group (RG) running, and hence can influence the measurements of $V_{us}$. Interestingly, through this mechanism, a single six-dimensional effective operator $O_{\ell \ell }$ at the high scale can alleviate the tension due to the Cabibbo angle anomaly, by generating the desired operators at the low scale through RG running. When generated as a result of a $Z^{\prime }$ model, the nonuniversal leptonic couplings of this operator can also contribute to the lepton flavor universality violating ratios such as $R_{K^{(*)}}$, which would act as stringent constraints on such scenarios. By performing a global fit of the $Z^{\prime }$ model, we find that it is essential to have nonuniversal couplings of such a $Z^{\prime }$ boson to all three generations of leptons.

The effective number of relativistic neutrino species is a fundamental probe of the early Universe, and its measurement represents a key constraint on many scenarios beyond the Standard Model of Particle Physics. In light of this, an accurate prediction of $N_{\mathrm{eff}}$ in the Standard Model is of pivotal importance. In this work, we consider the last ingredient needed to accurately calculate $N_{\mathrm{eff}}^{\mathrm{SM}}$: standard zero and finite-temperature QED corrections to $e^{+}{e}^{-}\leftrightarrow \nu \overline{\nu }$ interaction rates during neutrino decoupling at temperatures around $T\sim \mathrm{MeV}$. We find that this effect leads to a reduction of $-0.0007$ in $N_{\mathrm{eff}}^{\mathrm{SM}}$. This next-to-leading-order QED correction to the interaction rates, together with finite-temperature QED corrections to the electromagnetic density of the plasma, and the effect of neutrino oscillations, implies that $N_{\mathrm{eff}}^{\mathrm{SM}}=3.043$ with a theoretical uncertainty that is much smaller than any projected observational sensitivity.

Gravitational redshift can cause the distortion of photon wave packets; thus, the non-Markovian speedup evolution of a photon system must be controlled by considering gravitational redshift. We analyze the non-Markovian speedup dynamics of a photon system in the amplitude-damping channel or pure-dephasing channel under the effect of gravitational redshift, which is modelled as a beam-splitter operation. We show that the gravitational redshift weakens the non-Markovian dynamical behavior in both channels. For the amplitude-damping channel, the gravitational redshift promotes further speedup evolution of a photon system when the initial coherence of the system is nonzero. A stronger gravitational redshift and larger initial coherence make improving the evolution speed of the photon system easier. For the pure-dephasing channel, the non-Markovian dynamical behavior decreases owing to the gravitational redshift; however, the evolution speed of the photon is not influenced by the gravitational redshift.

$f(Q)$ gravity is an extension of the symmetric teleparallel equivalent to general relativity (STEGR). This work shows that based on the scalar-nonmetricity formulation, a scalar mode in $f(Q)$ gravity has a negative kinetic energy. This conclusion holds regardless of the coincident gauge frequently used in STEGR and $f(Q)$ gravity. To study the scalar mode, we further consider the covariant $f(Q)$ gravity as a special class in higher-order scalar tensor (HOST) theory and rewrite the four scalar fields, which play a role of the Stüeckelberg fields associated with the diffeomorphism, by vector fields. Applying the standard Arnowitt-Deser-Misner (ADM) formulation to the new formulation of the $f(Q)$ gravity, we demonstrate that the ghost scalar mode can be eliminated by the second-class constraints, thus ensuring that $f(Q)$ gravity is a healthy theory.

We show that “gravity at cosmological distances: explaining the accelerating expansion without dark energy” recently proposed by J. Harada [Phys. Rev. D 108, 044031 (2023)] is equivalent to the Einstein equation extended by the presence of an arbitrary conformal Killing tensor. This turns Harada’s equations of third order in the derivatives of the metric tensor to second order, and offers a strategy of solution that covariantly shortcuts Harada’s derivation and obtains both modified Friedmann equations. Another illustration is presented for the case of flat space and constant curvature.

The physical and mathematical properties of nonequatorial ($m\ne l$) scalar clouds that are supported by extremal Kerr black holes are studied analytically in the dimensionless large-mass $M\mu \gg 1$ regime (here $M$ is the mass of the central supporting black hole and $\{\mu ,l,m\}$ are respectively the proper mass, the spheroidal harmonic index, and the azimuthal harmonic index of the linearized scalar field). In particular, we determine the discrete resonant spectrum $m/l=m/l(M\mu )$ that characterizes the composed black hole nonequatorial-scalar-field cloudy configurations. Interestingly, we reveal the existence of a critical dimensionless angular ratio, $(m/l{)}_{\max }=(1+\frac{1}{4\sqrt{5}}{)}^{-1}<1$, above which maximally spinning Kerr black holes cannot support spatially regular bound-state configurations of the stationary massive scalar fields.

We utilize the probability distribution function (PDF) of normalized convergence maps reconstructed from the Subaru Hyper Suprime-Cam (HSC) year 1 shear catalogue, in combination with the power spectrum, to measure the matter clustering amplitude $S_8={\sigma }_8\sqrt{{\mathrm{\Omega }}_m/0.3}$. The large-scale structure’s statistical properties are incompletely described by the traditional two-point statistics, motivating our investigation of the PDF—a complementary higher-order statistic. By defining the PDF over the standard-deviation-normalized convergence map, we are able to isolate the non-Gaussian information. We use tailored simulations to compress the data vector and construct a likelihood approximation. We mitigate the impact of survey and astrophysical systematics with cuts on smoothing scales, redshift bins, and data vectors. We find $S_8=0.860_{-0.109}^{+0.066}$ from the PDF alone and $S_8=0.798_{-0.042}^{+0.029}$ from the combination of the PDF and power spectrum (68% confidential level (CL)). The PDF improves the power-spectrum-only constraint by about 10%.

A larger Planck scale during an early epoch leads to a smaller Hubble rate, which is the measure for efficiency of primordial processes. The resulting slower cosmic tempo can accommodate alternative cosmological histories. We consider this possibility in the context of extra dimensional theories, which can provide a natural setting for the scenario. If the fundamental scale of the theory is not too far above the weak scale, to alleviate the “hierarchy problem,” cosmological constraints imply that thermal relic dark matter would be at the GeV scale, which may be disfavored by cosmic microwave background measurements. Such dark matter becomes viable again in our proposal, due to a smaller requisite annihilation cross section, further motivating ongoing low energy accelerator-based searches. Quantum gravity signatures associated with the extra dimensional setting can be probed at high energy colliders—up to $\sim 13\mathrm{TeV}$ at the LHC or $\sim 100\mathrm{TeV}$ at FCC-hh. Searches for missing energy signals of dark sector states, with masses $\gtrsim 10\mathrm{GeV}$, can be pursued at a future circular lepton collider.

We proposed a cubic graphene periodic structure as a producer and probe of dark photons in an ordinary-sized laboratory. Utilizing modified Maxwell equations and hydrodynamic model in the system, corrections to dispersions of a collective excitation, plasmon, were demonstrated. If there is kinetic mixing between dark photons and ordinary matter, we found a significant difference in dispersion relationships, specifically a momentum gap in the plasmon dispersion curve. The relation between momentum gap, Compton wave of dark photons, and coupling between dark photon and ordinary photon was obtained. Considering the momentum gap, examining the effect of dark photons in the structure is not difficult.

It is possible that the strongest interactions between dark matter and the Standard Model occur via the neutrino sector. Unlike gamma rays and charged particles, neutrinos provide a unique avenue to probe for astrophysical sources of dark matter, since they arrive unimpeded and undeflected from their sources. Previously, we reported on annihilations of dark matter to neutrinos; here, we review constraints on the decay of dark matter into neutrinos over a range of dark matter masses from MeV to ZeV, compiling previously reported limits, exploring new electroweak corrections and computing constraints where none have been computed before. We examine the expected contributions to the neutrino flux at current and upcoming neutrino experiments as well as photons from electroweak emissions expected at gamma-ray telescopes, leading to constraints on the dark matter decay lifetime, which ranges from $\tau \sim 1.2\times {10}^{21}\mathrm{s}$ at 10 MeV to $1.5\times {10}^{29}\mathrm{s}$ at 1 PeV.

We study the impact of time-dependent solar cycles in the atmospheric neutrino rate at DUNE, Hyper-Kamiokande (HK), and JUNO, focusing in particular on the flux below 1 GeV. Including the effect of neutrino oscillations for the upward-going component that travels through the Earth, we find that across the solar cycle the amplitude of time variation is about $\pm 5\%$ at DUNE, $\pm 4\%$ at JUNO, and $\pm 1\%$ at HK. We find significant variance in the ratio of upward-going events to downward-going ones in all three experiments, though the overall event rates vary significantly across the three. Over the 11-year solar cycle, we find that the estimated statistical significance for observing time modulation of atmospheric neutrinos is $4.8\sigma$ for DUNE and $2.0\sigma$ for HK and JUNO. Flux measurements at all three experiments will be important for understanding systematics in the low-energy atmospheric flux as well as for understanding the effect of oscillations in low-energy atmospheric neutrinos.

Ultralight bosons are well-motivated particles from various physical and cosmological theories and can be spontaneously produced during the superradiant process, forming a dense hydrogenlike cloud around the spinning black hole. After the growth saturates, the cloud slowly depletes its mass through gravitational-wave emission. In this work we study the orbit dynamics of a circular binary system containing such a gravitational atom saturated in various spin-0, -1 and -2 superradiant states, taking into account both the effects of dynamical friction and the cloud mass depletion. We estimate the significance of mass depletion, finding that although dynamical friction could dominate the inspiral phase, it typically does not affect the outspiral phase driven by the mass depletion. Focusing on the large orbit radius, we investigate the condition to observe the outspiral and the detectability of the cloud via pulsar-timing signal in the case of black hole–pulsar binary.

Recent years, multiphoton pair production has become one of the most promising approaches to investigate the Schwinger effect. However, the production and evolution of chirality, a key topic in the study of this effect, has not been thoroughly considered in the context of multiphoton pair production. In this work, as the first step of filling this gap, we used the Dirac-Heisenberg-Wigner formalism to study the production and evolution of chirality in vacuum under the excitation of the spatially homogeneous electric and magnetic fields $\mathit{E}(t)$ and $\mathit{B}(t)$ that satisfy $\mathit{E}(t)\parallel \mathit{B}(t)$ and are only nonzero in a short time span $0<t<\tau$, which serve as a simplified model of the laser beams in multiphoton pair production experiments. Based on analytical calculation, we discovered that, after the external fields vanish, an oscillation of pseudoscalar condensate occurs in the system, which leads to the suppression of the chirality of the produced fermion pairs; at the same time, it introduces a special fermion energy ${\epsilon }_p=\sqrt{3}m$ at which the chiral charge distribution of the fermions maximizes. This novel phenomenon could help us identify different types of products in future multiphoton pair production experiments.

There exists a significant deviation between the most recent lattice quantum chromodynamics (QCD) simulation and experimental measurement by Belle for ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\ell }^{+}{\nu }_{\ell }$. In this work, we investigate the ${\mathrm{\Xi }}_c\to \mathrm{\Xi }$ form factors in QCD sum rules. To this end, the two-point correlation functions of ${\mathrm{\Xi }}_c$ and $\mathrm{\Xi }$, and the three-point correlation functions of ${\mathrm{\Xi }}_c\to \mathrm{\Xi }$ are calculated. At the QCD level, contributions from up to dimension-6 four-quark operators are considered, and the leading order results of the Wilson coefficients are obtained. For the form factors, relatively stable Borel windows can be found. Our form factors are comparable with those of lattice QCD, except for $f_{\perp }$. The obtained form factors are then used to predict the branching ratios of ${\mathrm{\Xi }}_c\to \mathrm{\Xi }{\ell }^{+}{\nu }_{\ell }$, and our predictions are consistent with the most recent data of ALICE and Belle, and those of lattice QCD within error. Given that the branching ratios only contain limited information, we suggest the experimentalists directly measure the form factors of ${\mathrm{\Xi }}_c\to \mathrm{\Xi }$.

We explore an odd class of quantum field theories where a hierarchy problem is resolved with new dynamics as opposed to new particles. The essential element of our construction is a $U(1)$ pseudo-Nambu-Goldstone boson with symmetry breaking interactions all characterized by a large number $N$ of units of the fundamental charge. In the resulting effective theory, quantum corrections, like those to the effective potential and mass, which are normally power divergent and saturated at the UV cutoff, are instead saturated at a much lower scale. This critical scale, which does not involve any new particle, corresponds to the onset of unsuppressed multiparticle production in scattering processes. Remarkably, this all happens within the tractable domain of weak coupling. Terms involving arbitrarily high powers of the Goldstone field must, however, be taken into account. In particular, a truncation to the renormalizable part of the effective Lagrangian would completely miss the physics.

We study the Dirac decomposition of the gauge-invariant quark propagator, whose imaginary part describes the hadronization of a quark as this interacts with the vacuum, and relate each of its coefficients to a specific sum rule for the chiral-odd and chiral-even quark spectral functions. Working at first in lightlike axial gauge, we obtain a new sum rule for the spectral function associated with the gauge-fixing vector and show that its second moment is, in fact, equal to zero. Then, we demonstrate that the first moment of the chiral-odd quark spectral function is equal in any gauge to the so-called inclusive jet mass, which is related to the mass of the particles produced in the hadronization of a quark. Finally, we present a gauge-dependent formula that connects the second moment of the chiral-even quark spectral function to invariant mass generation and final state rescattering in the hadronization of a quark.

We study the nonstrange and strangeonium light hybrid mesons with $J^{PC}=2^{+-}$ by using the method of QCD sum rules. The local hybrid interpolating currents with three Lorentz indices are constructed to couple to such exotic quantum numbers. We calculate the correlation functions up to dimension eight condensates at the leading order of ${\alpha }_s$. In our results, the masses of the nonstrange $b_2$ and $h_2$ hybrids are about 2.65 GeV, while that of the strangeonium $h_2^{\prime }$ hybrid is about 2.72 GeV. Such exotic $2^{+-}$ hybrids can be generated through both the two-gluon and three-gluon emission processes in the radiative decays of ${\chi }_{cJ}$. Moreover, these hybrid mesons may be detectable due to their peculiar decay behaviors and small decay widths. Using the high-statistics data samples of $\psi (3686)$ in BESIII and BelleII, it is possible to hunt for such hybrid states through the partial wave analyses in the $b_2\to \omega /a_1/h_1/a_2\pi \to 4\pi$, $h_2\to \rho \pi \to 3\pi$, and $h_2\to b_1\pi \to 5\pi$ processes.

The partons’ transverse momentum can be explored with QCD lattice simulations by studying the quasitransverse-momentum-dependent parton distribution functions (qTMDPDFs), which are factorized in terms of physical TMDPDFs and soft factors in the limit of the large hadron’s momentum. We present the next-to-next-to-leading order (NNLO) calculation of the coefficient function for this factorization. Together with already known expressions for anomalous dimensions, this result allows analysis of lattice data at NNLO perturbative accuracy.