Motivated by recent experimental advances in three-body hadronic $D$ decays from BESIII, we present a systematic analysis of $D_{(s)}\to P_1(V\to )P_2{P}_3$ decay processes, where $V$ denotes vector resonances ($\rho ,K^{*},\omega$, $\varphi$) and $P_{1,2,3}$ are light pseudoscalar mesons ($\pi ,K,{\eta }^{(\prime )}$). Using the factorization-assisted topological-amplitude (FAT) approach, we calculate the intermediate subprocesses $D_{(s)}\to P_{1}V$, incorporating relativistic Breit-Wigner distributions to model the subsequent $V\to P_2{P}_3$ strong decays. By comprehensively including all relevant resonances ($\rho ,K^{*},\omega ,\varphi$), we calculate branching fractions for these decay modes as well as the Breit-Wigner-tail effects in $D_{(s)}\to P_1(\omega \to )KK$ processes. Our framework comprehensively incorporates both factorizable and nonfactorizable contributions, significantly improving theoretical predictions in the nonperturbative regime where conventional methods face challenges due to the limited mass scale of charm mesons. The FAT approach yields results in good agreement with experimental data, demonstrating its effectiveness in capturing nonfactorizable contributions with improved precision. Our predictions for yet-unobserved decay modes, particularly those with branching fractions in the order of ${10}^{-4}–{10}^{-3}$, are expected to be tested in future high-precision experiments at BESIII and LHCb.

Within the nonrelativistic QCD framework, we calculate the double heavy quarkonium (double charmonium and double bottomonium) production at a future super $Z$ factory and at the Circular Electron Positron Collider (CEPC) and Electron-Positron Future Circular Collider (FCC-ee). The complete color-octet (CO) channels in the ${\gamma }^{*}/Z^{*}$-propagated process are considered along with the color-singlet (CS) channels at leading order of ${\alpha }_s$. We found that the contributions of CO states to the total cross section are significant or dominant for many processes within the energy region at a $Z$ factory and at the CEPC and FCC-ee. The experimental measurements will help us to verify the CO mechanism. Among these CO channels, the gluon fragmentation process (into ${{}^{3}S}_1^8$ states at leading order) is most important. The comparison between the theoretical results and future data may give constraints to the CO matrix elements. Additionally, we consider the relativistic corrections to both the CS and CO channels which decrease the cross sections significantly. Specially, the $K$ factors are about 0.5 for most charmonium channels. We get estimates of the events for double heavy quarkonium production. The final events of $J/\psi +{\eta }_c$, $J/\psi +J/\psi$, and ${\eta }_c+{\eta }_c$ production, with $J/\psi$ reconstructed by lepton pair and ${\eta }_c$ reconstructed by hadronic decays, would be (1, 8, 4) and (11, 77, 37) at the CEPC (2-yr) and at the FCC-ee (4-yr) for the $Z$ factory mode, respectively.

We explore flavored resonant leptogenesis embedded in a neutrinophilic two-Higgs-doublet model. Successful leptogenesis is achieved by the very mildly degenerate two heavier right-handed neutrinos (RHNs) $N_2$ and $N_3$ with a level of only $\mathrm{\Delta }{M}_{32}/M_2\sim \mathcal{O}(0.1\%–1\%)$. The lightest RHN, with a MeV–GeV mass, lies below the sphaleron freeze-out temperature and is stable, serving as a dark matter candidate. The model enables TeV-scale leptogenesis while avoiding the extreme mass degeneracy typically plaguing conventional resonant leptogenesis. Baryon asymmetry, neutrino masses, and potentially even dark matter relic density can be addressed within a unified, experimentally testable framework.

Gauge anomalous quantum field theories are inconsistent as full UV theories since they lead to the breaking of Lorentz invariance or unitarity, as well as nonrenormalizability. It is well known, however, that they can be interpreted as effective field theories (EFT) with a cutoff. The latter cannot be made arbitrarily large, and it is related to the energy scale at which additional fermions with suitable gauge charges enter, rendering the full model anomaly free. A nondecoupling effect that remains in the EFT is the appearance of anomalous loop-induced triple-gauge couplings, encapsulating information from the full UV theory. In this work, we take as an example an Abelian gauge symmetry $U(1{)}_{\mu }^{\prime }$ under which second-generation leptons are axially charged, leading to an EFT that consists of the Standard Model (SM) with an additional massive $Z^{\prime }$ gauge boson. As a consequence, there are triple-gauge couplings involving the $Z^{\prime }$ and electroweak SM gauge bosons via mixed gauge anomalies. We study the possibility of probing these loop suppressed anomalous couplings at hadron and lepton colliders, with $Z^{\prime }$-lepton couplings allowed by current experimental bounds, finding that due to the large SM backgrounds and small signal, the HL-LHC is incapable of this task. The 100 TeV $pp$ collider at $\mathcal{L}=20{\mathrm{ab}}^{-1}$ on the other hand could probe anomalous couplings for $m_{Z^{\prime }}\in [150,800]\mathrm{GeV}$ and obtain discovery significances for $m_{Z^{\prime }}\in [230,330]\mathrm{GeV}$. Lepton colliders are also well suited for probing these anomalous couplings. In particular, we show that a muon collider running at the $Z^{\prime }$ resonance and an electron-positron collider such as CLIC with $\sqrt{s}=3\mathrm{TeV}$ can be complimentary in probing the anomalous couplings for $m_{Z^{\prime }}\in [100,700]\mathrm{GeV}$, with CLIC sensitive to discovery for $m_{Z^{\prime }}\in [125,225]\mathrm{GeV}$.

Recently, the Belle II Collaboration reported the branching fraction $\mathcal{B}(B^{+}\to K^{+}\nu \overline{\nu })=(2.3\pm 0.7)\times {10}^{-5}$ with a significance of $3.5\sigma$, which is $2.7\sigma$ above the Standard Model expectation. Motivated by this measurement, we calculate this decay channel at the next-to-leading order and twist-three level using the perturbative QCD approach. By combining lattice QCD data with our results, we obtain form factors with improved reliability. Using these form factors, we estimate the branching ratios of $B^{+}\to K^{+}$ semileptonic flavor-changing neutral current decays, including $B^{+}\to K^{+}\nu \overline{\nu }$ and $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$. To address the anomalies in these two processes, we introduce a leptoquark model as a new physics scenario. Analyzing five possible types of leptoquarks, we successfully explain the latest experimental measurements and derive further constraints on the leptoquarks. Furthermore, the single leptoquark model becomes invalid once the stringent constraints from process $B_s\to {\mu }^{+}{\mu }^{-}$ and $B_s-\overline{B_s}$ mixing is taken into account.

We explore the top quark flavor-changing four-fermion interactions ($tuee$ and $tcee$) with scalar, vector, and tensor structures using machine learning models to analyze trilepton processes at the LHC. The study is performed using $t\overline{t}$ and $tW$ processes, where a top quark decays into $u/c+e^{+}+e^{-}$. The analysis incorporates both reducible and irreducible backgrounds while accounting for realistic detector effects. The dominant backgrounds for these trilepton signatures arise from $t\overline{t}$ production, single top quark production in association with $V$, and $VV$ production (where $V=W$, $Z$). These backgrounds are significantly reduced using machine-learning-based classification models, which optimize event selection and improve signal sensitivity. For an integrated luminosity of $3000{\mathrm{fb}}^{-1}$ at the LHC, we find that the expected 95% confidence level (CL) limits on the scale of four-fermion flavor-changing neutral current interactions reach $\mathrm{\Lambda }\le 5.5\mathrm{TeV}$ for $tuee$ and $\mathrm{\Lambda }\le 5.7\mathrm{TeV}$ for $tcee$ in the $t\overline{t}$ channel, and $\mathrm{\Lambda }\le 1.9\mathrm{TeV}$ ($tuee$) and $\mathrm{\Lambda }\le 2.0\mathrm{TeV}$ ($tcee$) in the $tW$ channel. We also provide an interpretation of our EFT analysis in the context of a specific $Z^{\prime }$ model, illustrating how the derived constraints translate into bounds on the parameter space of a heavy neutral gauge boson mediating flavor-changing interactions.

We consider the 3-state Potts model in $d\ge 2$ dimensions. For $d$ less than the upper critical dimension $d_{\mathrm{crit}}$, the model has a critical and a tricritical fixed point. In $d=2$, these fixed points are described by minimal models, and so are exactly solvable. For $d>2$, however, strong coupling makes them difficult to study and there is no consensus on the value of $d_{\mathrm{crit}}$. We use the numerical conformal bootstrap to compute critical exponents of both the critical and tricritical fixed points for general $d$. In $d=2$ our results match the expected values, and as we increase $d$ we find that the critical exponents of each fixed point get closer until they merge near $d_{\mathrm{crit}}\lesssim 2.5$, which is an upper bound on $d_{\mathrm{crit}}$.

We present a numerical linear programming bootstrap to construct dual model scattering amplitudes. Dual models describe tree-level exchanges of higher spin resonances in theories like string theory and large $N$ gauge theories. Despite being very simple objects, their numerical bootstrap has proven challenging due to slow convergence of the infinite sums over resonances. Our bootstrap succeeds thanks to an efficient parametrization of the amplitude in terms of Mandelstam-Regge poles and the use of combined regions that make crossing symmetry constraining. Along the way, we discover and conjecture a property of “superunitarity” of the Veneziano amplitude, which we use to keep a linear problem. As results, we present first the study of a class of stringlike amplitudes with linear trajectories, for which we observe that the Veneziano amplitude lies at a preferred location, at the bottom of a pit, which minimizes crossing. Then, we introduce a toy-model deformation to nonlinear trajectories, mimicking some features of QCD, for which our algorithm also detects a clear pit. This gives compelling evidence that our bootstrap is able to produce amplitudes that can exhibit nontrivial phenomenological features.

We consider the chiral phase transition relevant for QCD matter at finite temperature but with vanishing baryon density. Presumably, the chiral phase transition is of second order for two-flavor QCD in the chiral limit [F. Cuteri et al., On the order of the QCD chiral phase transition for different numbers of quark flavours, J. High Energy Phys. 11 (2021) 141.]. Near the transition temperature, we apply the Schwinger-Keldysh formalism and construct a low-energy effective field theory for the system, in which fluctuations and dissipations are systematically captured. The dynamical variables involve the chiral charge densities and order parameter (chiral condensate). Via the holographic Schwinger-Keldysh technique, the effective action is further confirmed within a modified anti–de Sitter QCD model. With higher-order terms suitably neglected, the stochastic equations derived from the effective field theory resemble those of model F in the Hohenberg-Halperin classification. Within the effective field theory, we briefly discuss the spontaneous breaking of chiral symmetry and Goldstone modes.

Theoretical approaches to QED scattering in strong fields typically treat the field as a fixed background with simple spacetime dependence, such as a plane wave. Two major challenges are therefore the inclusion of backreaction (e.g., depletion of the field) and spatial geometry (e.g., focusing). We show here that a solution to one problem can solve the other: even if particle wave functions in a chosen focused background are not known, we show they can be constructed once depletion is accounted for. We demonstrate this by giving the exact wave functions in a flying focus beam for which all energy is absorbed by particles scattering on it. In addition we use the wave functions to obtain a simple expression for the nonlinear Compton scattering amplitude, comparing with the plane wave case. Our methods thus open a new avenue of investigation in which two previously challenging effects are simultaneously brought under analytic control.

We advance the study of pure de Sitter supergravity by introducing a finite formulation of unimodular supergravity via the super-Stückelberg mechanism. Building on previous works, we construct a complete four-dimensional action of spontaneously broken $\mathcal{N}=1$ supergravity to all orders in the Stückelberg fields, which allows for de Sitter solutions. The introduction of finite supergravity transformations extends the super-Stückelberg procedure beyond the second order, offering a recursive solution to all orders in the Goldstino sector. This work bridges the earlier perturbative approaches and the complete finite theory, opening new possibilities for de Sitter vacua in supergravity models and eventually string theory.

The first black hole solutions of the SU(N) Bach-Yang-Mills equations are presented. Static generalizations breaking spherical symmetry are also constructed. These constitute the first examples in the literature of C-metrics sourced by a Yang-Mills field.

We investigate the propagation of massive scalar fields in the background of four-dimensional Einstein-Gauss-Bonnet black holes with de Sitter (dS) asymptotics. Our study focuses on the various branches of quasinormal modes present in this background, employing the pseudospectral Chebyshev method and the third-order Wentzel-Kramers-Brillouin approximation. We identify that the introduction of the Gauss-Bonnet coupling constant $\alpha$ gives rise to three branches of modes: the perturbative (in $\alpha$) Schwarzschild branch, the perturbative (in $\alpha$) dS branch, and a nonperturbative (in $\alpha$) dS branch. Our results show that the propagation of a massive scalar field is stable in this background. Furthermore, the Gauss-Bonnet coupling constant induces significant deviations in the Schwarzschild branch and smaller deviations in the perturbative dS branch compared to the corresponding branches in the Schwarzschild-dS limit. Additionally, the nonperturbative dS branch of modes, absent when $\alpha =0$, emerges as a novel feature of the Einstein-Gauss-Bonnet framework.

We study the possibility of the highest energy neutrino event with 220 PeV energy, detected recently by the KM3NeT experiment to be originating from heavy dark matter (DM) decay. Considering a heavy right handed neutrino (RHN) DM for illustrative purposes, we show that DM mass of 440 PeV, can explain the observed flux. The required DM lifetime to produce the best-fit value of the neutrino flux saturates the existing gamma-ray bounds. Due to the large uncertainty in the flux, it is possible to explain the KM3NeT event from RHN DM decay at $3\sigma$ confidence level (CL) while being in agreement with gamma-ray bounds and nonobservation of similar events at IceCube. While we consider a gauged $B-L$ scenario where DM relic can be generated due to other interactions, we also briefly discuss some alternate DM possibilities where the gamma-ray bounds can be alleviated compared to the minimal RHN DM discussed here.

Ionization or excitation resulting from the noninstantaneous response of the electron cloud to nuclear recoil is known as the Migdal effect. Dark matter searches utilizing this process set the most stringent bounds on the spin-independent dark matter–nucleon scattering cross section over a large region of the sub-GeV dark matter parameter space, underscoring its significance in dark matter detection. In this paper, we quantify the regions of dark matter parameter space that are challenging to probe via the Migdal effect due to the presence of dominant solar neutrino backgrounds for both liquid noble and semiconductor targets. Our findings reveal that there is no hard floor in the dark matter parameter space. Instead, we map the so-called neutrino fog. In mapping the neutrino fog, we identify the importance of incorporating the Migdal effect induced by neutrinos, as well as neutrino-electron scattering and dominant coherent neutrino-nucleus scattering, particularly for semiconductor targets. Furthermore, we demonstrate that a large portion of the relic density allowed parameter space lies within the neutrino fog. Finally, we estimate the exposure required to detect neutrino-induced Migdal events in direct detection experiments.

Axionlike particles (alps), hypothetical light particles beyond the Standard Model, are expected to mix with photons in the presence of magnetic fields. This mixing can alter the propagation of high-energy gamma rays across cosmological distances. In this study, we investigate this effect by performing spectral fits to observations of multiple blazars, incorporating the photon-ALP oscillation mechanism. We use Monte Carlo simulations to fit the observed spectra under both the ALP and null hypotheses, evaluating model performance through chi-squared statistics. When the ALP mass lies in the range of $4.4\times {10}^{-10}\mathrm{eV}\le m_a\le 1.3\times {10}^{-8}\mathrm{eV}$, the ALP-photon coupling constant, $g_{a\gamma }$, is constrained to be below approximately $3.6\times {10}^{-11}{\mathrm{GeV}}^{-1}$. This parameter region is particularly favored in the scan of the ALP parameter space. We find that ALP effects are more pronounced during flaring states and in environments with stronger magnetic fields, resulting in improved spectral fits and tighter constraints on $m_a$ and $g_{a\gamma }$. Moreover, the normalized chi-squared difference between the ALP and null hypotheses increases with redshift, indicating that photon-ALP mixing becomes more significant over longer propagation distances. These results support the presence of photon-ALP conversion in high-energy astrophysical environments and suggest that alps may offer a more effective explanation for certain features in gamma-ray spectra, especially at high redshifts. Our findings provide new insights that may guide future observational and theoretical studies of ALP physics.

We provide a comprehensive comparison of linear amplifiers and microwave photon counters in axion dark matter experiments. The study is done assuming a range of realistic operating conditions and detector parameters, over the frequency range between 1 and 30 GHz. As expected, photon counters are found to be advantageous under low background, at high frequencies ($\nu >5\mathrm{GHz}$), if they can be implemented with robust wide-frequency tuning or a very low dark count rate. Additional noteworthy observations emerging from this study include: (1) an expanded applicability of off-resonance photon background reduction, including the single-quadrature state squeezing, for scan rate enhancements; (2) a much broader appeal for operating the haloscope resonators in the overcoupling regime, up to $\beta \sim 10$; (3) the need for a detailed investigation into the cryogenic and electromagnetic conditions inside haloscope cavities to lower the photon temperature for future experiments; (4) the necessity to develop a distributed network of coupling ports in high-volume axion haloscopes to utilize these potential gains in the scan rate.