Anisotropic flow is accredited to have effects from the initial state geometry and fluctuations in the nuclear overlap region. The elliptic flow ($v_2$) and triangular flow ($v_3$) coefficients of the final state particles are expected to have influenced by eccentricity (${ϵ}_2$) and triangularity (${ϵ}_3$) of the participants, respectively. In this work, we study $v_2$, $v_3$, ${ϵ}_2$, ${ϵ}_3$, and the correlations among them with respect to event topology in the framework of a multiphase transport model (AMPT). We use transverse spherocity and reduced flow vector as event shape classifiers in this study. Transverse spherocity has the unique ability to separate events based on geometrical shapes, i.e., jetty and isotropic, which pertain to pQCD and non-pQCD domains of particle production in high-energy physics, respectively. We use the two-particle correlation method to study different anisotropic flow coefficients. We confront transverse spherocity with a more widely used event shape classifier–reduced flow vector ($q_n$) and they are found to have significant (anti)correlations among them. We observe significant spherocity dependence on $v_2$, $v_3$, and ${ϵ}_2$. This work also addresses transverse momentum dependent crossing points between $v_2$ and $v_3$, which varies for different centrality and spherocity percentiles.

Stimulated by the recent experimental progress on the $T_{\psi \psi }$ states, the fully charmed tetraquark spectroscopy is systemically investigated by dint of the Godfrey-Isgur relativized diquark model, the modified Godfrey-Isgur relativized diquark model with the color screening effects, and the nonrelativistic diquark model. The theoretical results of the diquark-antidiquark scenarios propose to interpret the $T_{\psi \psi }(6200)$, $T_{\psi \psi }(6600)$, $T_{\psi \psi }(6900)$, and $T_{\psi \psi }(7300)$ structures as the candidates of the $1S$-wave, $1P/2S$-wave, $1D/2P$-wave, and $2D/3P/4S$-wave fully charmed tetraquark states, respectively. On account of the deficiency of sufficient experimental information, e.g., the parities of the newly observed $T_{\psi \psi }$ states, there are uncertainties about the assignments of the $T_{\psi \psi }(6600)$, $T_{\psi \psi }(6900)$, and $T_{\psi \psi }(7300)$ states. It is demonstrated that the further experimental survey on the $cc\overline{c}\overline{c}$ states, implemented by the LHCb, ATLAS, CMS, and other collaborations, ought to be continued in the future.

We study the leading-twist unpolarized generalized parton distributions (GPDs) of light and heavy vector mesons, i.e., the $\rho$, $J/\psi$, and $\mathrm{\Upsilon }$, at zero skewness. An ansatz incorporating the zero-mode contribution is introduced to modify the light front overlap representation of GPDs. The leading Fock-state light front wave functions of vector mesons from Dyson-Schwinger and Bethe-Salpeter equations approach are then employed to study the meson GPDs. The light front spatial distribution of valence quarks within vector mesons is then studied with the impact parameter dependent GPD. We also investigate the electromagnetic and gravitational form factors, which are the first and second Mellin moments of the GPDs. The light-cone mass radius of $\rho$ is determined to be 0.30 fm, close to a recent Nambu-Jona-Lasinio model prediction of 0.32 fm. For $J/\psi$ and $\mathrm{\Upsilon }$, they are predicted to be 0.151 fm and 0.089 fm respectively.

Two observed structures with $M=1868\pm 8_{-57}^{+40}\mathrm{MeV}$ and $M=2073\pm 94_{-240}^{+245}\mathrm{MeV}$ are the same states [$K_2^{*}(1980)$] in Particle Data Group. In this paper, analysis of the mass spectrum and calculation of the strong decay for $K_2^{*}$ mesons support the assignment of $2^3{P}_2$ and $1^3{F}_2$ as the low- and high-mass states for $K_2^{*}(1980)$. This analysis reveals very important criteria for the assignment of the observed $K_2^{*}(1980)$, and experimental findings for this assignment are suggested. Additionally, some partial decay widths are predicted based on the high excitations of the $K_2^{*}$ family. This study is crucial for establishing and searching for the higher excitations in the future.

Generalized complete intersection Calabi-Yau manifold (gCICY) is a new construction of Calabi-Yau manifolds established recently. However, the standard algebraic method to generate new gCICYs is very laborious. Because of this complexity, the number of gCICYs and their classification still remains unknown. In this paper, we try to make some progress in this direction using neural networks. Our results showed that the trained models cannot only get high accuracy on the type (1, 1) and type (2, 1) gCICYs existing in the literature but also achieve a 97% accuracy in predicting new gCICYs not used in the training. This shows that machine learning is an effective method to classify and generate new gCICY.

Entanglement is the quantum signature of Hawking’s particle pair creation from causal horizons, for gravitational and analog systems alike. Ambient thermal fluctuations, ubiquitous in realistic situations, strongly affect the entanglement generated in the Hawking process, completely extinguishing it when the ambient temperature is comparable to the Hawking temperature. In this work, we show that optical analog systems have a built-in robustness to thermal fluctuations which are at rest in the laboratory. In such systems, horizons move relative to the laboratory frame at velocities close to the speed of light. We find that a subtle interplay between this relative velocity and dispersion protects the Hawking-generated entanglement—allowing ambient temperatures several orders of magnitude larger than the Hawking temperature without significantly affecting entanglement.

Black hole superradiance provides a window into the dynamics of light scalar fields and their interactions close to a rotating black hole. Owing to the rotation of the black hole, the amplitude of the scalar field becomes magnified, leading to a “black hole bomb” effect. Recent work has demonstrated that rotating black holes in dynamical Chern-Simons gravity possess unique structures, the “Chern-Simons caps,” which may influence the behavior of matter near the black hole. Motivated by the presence of these caps, we study superradiance in dynamical Chern-Simons gravity in the context of a slowly rotating black hole. We find additional contributions to the superradiance beyond what is expected for a Kerr black hole. Studying the superradiant spectrum of perturbations, we find that the Chern-Simons contributions give rise to small corrections to the angular dependence of the resulting scalar cloud. Finally, we comment on potential observable consequences and future avenues for investigation.

We analyze the consequences of different evolutions of the Hubble parameter on the spectrum of scalar inflationary perturbations. The analysis is restricted to inflationary phases described by a transient evolution, when uncommon features arise in the inflationary spectra that may lead to an amplitude enhancement. We then discuss how the spectrum is, respectively, amplified or blue-tilted in the presence or absence of a growing solution of the Mukhanov-Sasaki equation. The cases of general relativity with a minimally coupled inflaton and that of induced gravity are considered explicitly. Finally, some remarks on constant roll inflation are discussed.

We study the time evolution of the numbers of charm mesons after the kinetic freeze-out of the hadron gas produced by a central heavy-ion collision. The $\pi D^{*}\to \pi D^{*}$ reaction rates have $t$-channel singularities that give contributions inversely proportional to the thermal width of the $D$. The ratio of the $D^0$ and $D^{+}$ production rates can differ significantly from those predicted using the measured $D^{*}$ branching fractions.

Dark matter may consist of feebly interacting massive particles (FIMPs) that never thermalized with the cosmic plasma. Their relic density is achieved via freeze-in for a wide range of masses, significantly expanding the model space that can be tested compared to other production mechanisms. However, testing the tiny couplings required by freeze-in is challenging. We show that FIMPs can be probed by LHC searches for new physics in monojet events with large missing energy. We study a $Z^{\prime }$ portal model in which gluon annihilation produces FIMPs in the early universe and today at colliders. Monojet searches by LHC Run 3 might discover new physics accounted for by FIMPs with mass in the MeV–TeV range.

We propose a solution to the recent $W$ mass measurement by embedding the Standard Model within $E_6$ models. The presence of a new $U(1)$ group shifts the $W$ boson mass at the tree level and introduces a new gauge boson $Z^{\prime }$ which has been searched for at collider experiments. In this article, we identify the parameter space that explains the new $W$ mass measurement and is consistent with current experimental $Z^{\prime }$ searches. As $U(1)$ extensions can be accommodated in supersymmetric models, we also consider the supersymmetric scenario of $E_6$ models, and show that a 125 GeV Higgs may be easily achieved in such settings.

We investigate the phase diagram and thermodynamics of $SU(N)$ pure Yang-Mills theory on a manifold ${\mathbb{T}}^2\times {\mathbb{R}}^2$ with an effective model that includes two Polyakov loops along two compactified directions. We find that a rich phase structure can appear owing to the spontaneous breaking of two center symmetries for $N=2$ and 3. Thermodynamic quantities are obtained in the model and compared with recent lattice results. It is shown that two Polyakov loops play significant roles in thermodynamics on ${\mathbb{T}}^2\times {\mathbb{R}}^2$.

We address the possibility of the appearance of a charged kaon condensate in neutron star cores described within a generalized Skyrme model. Our treatment of strange degrees of freedom is based on the bound state approach by Callan and Klebanov, which allows to obtain an in-medium effective potential for the $s$-wave kaon condensate. We predict the onset of kaon condensation at a certain threshold density—whose value depends on the parameters of the model, and ranges between 1.5 and 2.5 times saturation density—and obtain both the particle fractions and equation of state for dense matter in the kaon condensed phase. Finally, we discuss the effect of such condensates on the mass-radius curves and other observable properties of neutron stars with kaon condensed cores.

We study the axial transition form factors $G_A^{B\to B^{\prime }}(Q^2)$ as well as the axial charges $g_A^{B\to B^{\prime }}$ of the octet baryons in the perturbative chiral quark model (PCQM) with including both the ground and excited states in the intermediate quark propagators. The PCQM results on the $G_A^{B\to B^{\prime }}(Q^2)$ and the $g_A^{B\to B^{\prime }}$ are found in good agreement with the existing experimental data and the lattice-QCD values. The study figures out that the $G_A^{B\to B^{\prime }}(Q^2)$ for all transitions behave in the dipolelike form, which is dominantly caused by the three-quark core. The meson cloud with the ground-state quark propagator also plays an extremely important role but results in a flat contribution. The excited-state quark propagator contributing to the $G_A^{B\to B^{\prime }}(Q^2)$ could be regarded as the higher order correction and it is very limited.

In the paper, we present a calculation of the decay widths for the Higgs boson decays to the $B_c$, $B_c^{*}$, $B_c(2{}^1{S}_0)$, and $B_c^{*}(2{}^3{S}_1)$ mesons using the fragmentation-function approach. In the calculation, the fragmentation functions up to order ${\alpha }_s^3$ based on the nonrelativistic QCD factorization theory are used, and the decay widths for $H\to Q+X$ and $H\to g+X$ at the partonic level are calculated up to order ${\alpha }_s$. The large logarithms of $m_H^2/m_{Bc}^2$ are resummed up to next-to-leading logarithmic accuracy by solving the evolution equations for the running quark masses and the fragmentation functions. Compared to the leading-order decay widths based on the nonrelativistic QCD approach, the decay widths based on the fragmentation-function approach that include the higher-order QCD corrections are reduced significantly. Our numerical results show that there are about $1.2\times {10}^5$ $B_c$ events via the Higgs decays to be produced at the HL-LHC with $3{\mathrm{ab}}^{-1}$, and about $1.6\times {10}^6$ $B_c$ events via the Higgs decays to be produced at the HE-LHC with $15{\mathrm{ab}}^{-1}$.

Boosted dark matter is a promising method for probing light dark matter, with a well-developed computational framework for spin-independent scattering already existing. The spin-dependent case, on the other hand, lacks a coherent treatment. We therefore give the first comprehensive derivation of the spin-dependent scattering cross section for boosted dark matter, finding that certain effects can lead to enhanced experimental sensitivity compared to the conventional contact interaction. For example, when the transfer momentum is sufficiently large, the time component of the dark matter current contributes significantly to the proton structure factor. Also, even without a light mediator, we find a residual momentum dependence in the quark-nucleon matching operation that can contribute similarly. We promote this endeavor by deriving direct limits on sub-GeV spin-dependent scattering of boosted dark matter from terrestrial data. We find that the exclusion limits from the boosted structure factor differ by as much as six orders of magnitude from those calculated using nonrelativistic structure factors.

Flux-integrated semiexclusive differential cross sections for charged-current quasielastic and neutral-current elastic neutrino scattering on argon are analyzed. The cross sections are calculated using the relativistic distorted-wave impulse approximation with values of the nucleon axial mass $M_A=1\mathrm{GeV}$ and 1.2 GeV. The elastic scattering cross sections are also computed for different strange quark contributions to the neutral-current axial form factor. The flux-integrated differential cross sections as functions of reconstructed neutrino energy are evaluated for the far detector of the SBN experiment. The effects of the short baseline neutrino oscillations are taken into account in a $3+1$ framework. We found that cross sections depend on oscillation parameters and the ratio of the measured and predicted cross sections can be used in a sterile neutrino oscillation study.

The recent discovery of a radio-emitting neutron star with an ultralong spin period of 76 s, PSR J0901-4046, raises a fundamental question on how such a slowly rotating magnetized object can be active in the radio band. A canonical magnetic field of $1.3\times {10}^{14}\mathrm{G}$ estimated from the pulsar period and its time derivative is wholly insufficient for PSR J0901-4046 to operate. Consideration of a magnetic inclination angle of 10° estimated from the pulse width gives a higher magnetic field of $1.5\times {10}^{15}\mathrm{G}$, which is still an order of magnitude lower than the necessary minimum of $2.5\times {10}^{16}\mathrm{G}$ following from the death line for radio pulsars with magnetic fields exceeding the critical value $4.4\times {10}^{13}\mathrm{G}$. We show that if the observed microstructure of single pulses reflects relativistic beaming, the inferred surface magnetic field appears to be $3.2\times {10}^{16}\mathrm{G}$, and without this assumption it is no less than $2.7\times {10}^{16}\mathrm{G}$, which explains the existence of radio emission from PSR J0901-4046. This estimation makes PSR J0901-4046 a radio pulsar with the strongest magnetic field known and is a sign that PSR J0901-4046 slows down not by magnetic-dipole radiation, but rather by an electric current of 56 MA, when rotational energy is expended in accelerating charged particles over the polar cap.

We discuss quantum scale invariance in (scale invariant) gauge theories with both ultraviolet (UV) and infrared (IR) divergences. First, their Becchi-Rouet-Stora-Tyutin invariance is checked in two apparently unrelated approaches using a scale invariant regularization (SIR). These approaches are then shown to be equivalent. Second, for the Abelian case we discuss both UV and IR quantum corrections present in such theories. We present the Feynman rules in a form suitable for off-shell Green’s function calculations, together with their one-loop renormalization. This information is then used for the muon production cross section at one-loop in a quantum scale invariant theory. Such a theory contains not only new UV poles but also IR poles. While the UV poles bring new quantum corrections (in the form of counterterms), finite or divergent, that we compute, it is shown that the IR poles do not bring new physics. The IR quantum corrections, both finite and divergent, cancel out similarly to the way the IR poles themselves cancel in the traditional approach to IR divergences (in the cross section, after summing over virtual and real corrections). Hence, the evanescent interactions induced by the scale-invariant analytical continuation of the SIR scheme do not affect IR physics, as illustrated at one-loop for the muon production ($e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$) cross section.

We derive the equations of motion governing static dyonic matters, described in terms of two real scalar fields, in nonlinear electrodynamics of the Born-Infeld theory type. We then obtain exact finite-energy solutions of these equations in the quadratic and logarithmic nonlinearity cases subject to dyonic point-charge sources and construct dyonically charged black holes with relegated curvature singularities. In the case of quadratic nonlinearity, which is the core model of this work, we show that dyonic solutions enable us to restore electromagnetic symmetry, which is known to be broken in nondyonic situations by exclusion of monopoles. We further demonstrate that in the context of k-essence cosmology the nonlinear electrodynamics models possess their own distinctive signatures in light of the underlying equations of state of the cosmic fluids they represent. In this context, the quadratic and logarithmic models are shown to resolve a density-pressure inconsistency issue exhibited by the original Born-Infeld model k-essence action function as well as by all of its fractional-powered extensions. Moreover, it is shown that the quadratic model is uniquely positioned to give rise to a radiation-dominated era in the early universe among all the polynomial models and other examples considered.