We introduce 1P1Q, a novel quantum data encoding scheme for high-energy physics (HEP), where each particle is assigned to an individual qubit, enabling direct representation of collision events on quantum circuits without classical compression. We demonstrate the effectiveness of 1P1Q in quantum machine learning (QML) through two applications: a quantum autoencoder (QAE) for unsupervised anomaly detection and a variational quantum circuit (VQC) for supervised classification of top quark jets. Our results show that the QAE successfully distinguishes signal jets from background quantum chromodynamics (QCD) jets, achieving superior performance compared to a classical autoencoder while utilizing significantly fewer trainable parameters. Similarly, the VQC achieves competitive classification performance, approaching state-of-the-art classical models despite its minimal computational complexity. Furthermore, we validate the QAE on real experimental data from the CMS detector, establishing the robustness of quantum algorithms in practical HEP applications. These results demonstrate that 1P1Q provides an effective and scalable quantum encoding strategy, offering new opportunities for applying quantum computing algorithms in collider data analysis.

In scenarios where the Higgs is viewed as a pseudo-Nambu-Goldstone boson, the question of naturalness finds itself, from a phenomenological perspective, at a tipping point between direct searches and precision. If, by the end of the High-Luminosity LHC operation, all experimental results were to remain consistent with the Standard Model, precision Higgs coupling measurements would begin to drive the naturalness tension. To illustrate this from a fresh perspective, we construct a maximally natural “kitchen sink” model, throwing into the mix three approaches to symmetry-based naturalness: supersymmetry, twin Higgs, and pseudo-Nambu-Goldstone boson Higgs models with a Gegenbauer potential. In other words, we build a “supersymmetric Gegenbauer’s twin” model. This model not only maximizes naturalness, at least from a technical perspective, but can also interpolate between all three ingredients smoothly, revealing the interplay between direct exploration and precision. Implications for FCC-ee and FCC-hh are discussed.

We consider symmetry breaking of arbitrary gauge groups on a six-dimensional space-time which consists of a four-dimensional Minkowski space-time $M^4$ and a two-dimensional sphere $S^2$. We expand the gauge fields in the presence of a nontrivial background unique to $S^2$. We analyze Kaluza-Klein (KK) modes of the gauge fields and derive the mass spectrum of the KK modes. We found that the gauge fields (not) commuting with the background fields (do not) remain symmetry operators in four dimensions. We also discuss the mass spectrum of the extra-dimensional components of the gauge fields and identify a physical scalar $\varphi$ and a Nambu-Goldstone mode $\chi$. As a result, we obtain a method to break gauge symmetry due to the nontrivial solution for gauge fields which is a unique feature of $S^2$.

Within the general $U(1)$ scenario, we demonstrate that the ultrahigh-energy neutrinos recently detected by KM3NeT could originate from a decaying right-handed neutrino dark matter, with a mass of 440 PeV. Considering dark matter production via freeze-in, we delineate the parameter space that satisfies the observed relic abundance and also lies within the reach of multiple gravitational wave detectors. Our study provides a testable new physics scenario, enabled by multimessenger astronomy.

In the Pati-Salam gauge symmetry $SU(4{)}_c\times SU(2{)}_L\times SU(2{)}_R$ (4-2-2, for short), the observed quarks and leptons of each family reside in the bi-fundamental representations (4,2,1) and $(\overline{4},1,2)$. There exist, however, the fundamental representations (4,1,1), (1,2,1), and (1,1,2) and their Hermitian conjugates, which show the presence, in principle, of yet to be discovered color triplets that carry electric charge $\pm e/6$, and color singlet particles with charges of $\pm e/2$. These standard model charges are in full accord with the fact that the 4-2-2 model predicts the presence of a topologically stable, finite energy magnetic monopole that carries two quanta of Dirac magnetic charge, i.e., $4\pi /e$, as well as color magnetic charge that is screened beyond the quark confinement scale. The 4-2-2 model, therefore, predicts the existence of exotic baryons, mesons, and leptons that carry fractional ($\pm e/2$) electric charges. Since their origin lies in the fundamental representations of 4-2-2, these exotic particles may turn out to be relatively light, in the TeV mass range or so. The 4-2-2 magnetic monopole mass depends on the 4-2-2 symmetry breaking scale, which is approximately 100 TeV.

We explore leptogenesis during a cosmological epoch during which the electroweak $\mathrm{SU}(2{)}_L$ force is confined. During weak confinement, there is only one conserved nonanomalous global charge, $r$, which is a linear combination of lepton-number, baryon-number, and hypercharge. The inclusion of heavy Majorana neutrinos leads to an $r$-charge and $CP$-violating interaction with a composite scalar, $\mathrm{\Phi }$, and composite fermions, $\mathrm{\Psi }$, allowing for the generation of an $r$-charge asymmetry, which translates into a baryon asymmetry post $\mathrm{SU}(2{)}_L$ deconfinement. Determining the resulting baryon asymmetry as a function of the model parameters, we find that the predicted baryon-asymmetry can match observations for a wide swath of parameter space: a weak confinement scale ${\mathrm{\Lambda }}_W\sim {10}^{11}–{10}^{14}\mathrm{GeV}$, the sum of the Standard Model Yukawa couplings $\sum Y_{i\alpha }{Y}_{i\alpha }^{*}\sim {10}^{-2}-{10}^0$, $m_{\mathrm{\Phi }}/m_{\mathrm{\Psi }}\sim 0-0.5$, and a $\mathrm{\Phi }-\mathrm{\Psi }-\mathrm{\Psi }$ coupling $|g|\sim 1$ with complex phase ${\theta }_g\sim \pi /4$. While leptogenesis under the assumption of a standard cosmology relies on the complex phase of the neutrino Yukawa couplings, the asymmetry generated in this novel background cosmology primarily depends on a strong phase from $\mathrm{SU}(2{)}_L$ confinement, ${\theta }_g$, and favors negligible $CP$-violation in the right-handed neutrino decays.

Nontrivial electromagnetic properties of neutrinos are an avenue to physics beyond the Standard Model (SM). To this end, we investigate the power of monophoton signals at neutrino experiments to probe a higher-dimensional operator connecting neutrinos to SM photons dubbed, neutrino polarizability. A simplified scenario giving rise to this operator involves a new pseudoscalar that couples to both neutrinos and photons, with clear implications for axionlike particle (ALP) and Majoron physics. By analyzing the photon energy spectrum and angular distributions, we find that NOMAD and MiniBooNE currently set the most stringent limits, while short baseline near detector and the DUNE near detector will soon provide significantly improved constraints.

We identify a new production channel for quantum chromodynamics (QCD) axions in supernova environments that contributes to axion emissivity for all models solving the strong $CP$ problem. This channel arises at tree-level from a shift-symmetry-breaking operator constructed at next-to-leading order in chiral perturbation theory. In scenarios where model-dependent derivative couplings to nucleons are absent, this sets the strongest model-independent constraint on the axion mass, improving on existing bounds by two orders of magnitude.

Axionlike particles (ALPs), hypothetical particles beyond the Standard Model (SM), are considered as promising dark matter candidates. ALPs can convert into photons and vice versa in a magnetic field via the Primakoff effect, potentially generating detectable oscillation in $\gamma$-ray spectra. This study analyzes 16.5 years of data from the Fermi Large Area Telescope (Fermi-LAT) on NGC 1275, the brightest galaxy in the Perseus cluster, to constrain the ALP parameter space. Our results improve the previous 95% exclusion limits of the photon-ALP coupling $g_{a\gamma }$ by a factor of 2 in the ALP mass range of $4\times {10}^{-10}\mathrm{eV}\lesssim m_a\lesssim 5\times {10}^{-9}\mathrm{eV}$. Moreover, we investigate the projected sensitivity of the future Very Large Area $\gamma$-ray Space Telescope (VLAST) on searching for ALPs. We find that (i) the expected sensitivity on the photon-ALP coupling $g_{a\gamma }$ can be stronger than that from the upcoming International Axion Observatory in the ALP mass range of $2\times {10}^{-11}\mathrm{eV}\lesssim m_a\lesssim 1\times {10}^{-7}\mathrm{eV}$, with the best sensitivity of $g_{a\gamma }\sim 7\times {10}^{-13}{\mathrm{GeV}}^{-1}$ at $m_a\sim 2\times {10}^{-10}\mathrm{eV}$; (ii) VLAST can extend the sensitivity of the ALP masses below $5\times {10}^{-12}\mathrm{eV}$, where the photon-ALP coupling $g_{a\gamma }\gtrsim 1.5\times {10}^{-11}{\mathrm{GeV}}^{-1}$ will be excluded; (iii) the entire parameter space of ALP accounting for TeV transparency can be fully tested. These results demonstrate that VLAST will offer an excellent opportunity for ALPs searches.

Lattice-quantum chromodynamics (QCD) simulations and theoretical arguments hint at the existence of an intermediate phase of strongly interacting matter between a confined hadron gas and a deconfined quark-gluon plasma (QGP). We qualitatively and semiquantitatively explore and differentiate the phase structures in the temperature window from the QCD pseudocritical temperature $T_{\mathrm{c}}\simeq 160\mathrm{MeV}$ to the pure gluonic deconfinement temperature $T_{\mathrm{d}}\simeq 285\mathrm{MeV}$. We propose a three-regime picture using a hadron resonance gas description augmented with the exponential spectrum of strings, corresponding to highly excited mesons and glueballs, based on the analysis of a large number $N_{\mathrm{c}}$ of colors. We estimate the entropy density from our model to confirm that the lattice-QCD data are bracketed with three regimes, i.e., a hadron gas, a QGP, and a new phase for $T_{\mathrm{c}}\lesssim T\lesssim T_{\mathrm{d}}$. In this new phase, which we name a spaghetti of quarks with glueballs (SQGBs), thermal degrees of freedom of quarks are liberated, yet gluons remain confined in glueballs. Since the Hagedorn temperature $T_{\mathrm{H}}\sim 285\mathrm{MeV}$ is universal in the meson and the glueball sectors, in the infinite-$N_{\mathrm{c}}$ limit, the phase diagram in the plane of the baryon chemical potential and the temperature is reduced to one with the confined and deconfined phases and quarkyonic matter at high density. At large but finite $N_{\mathrm{c}}$, an SQGB window may open between these phases. We point out that the SQGB has interesting similarities with quarkyonic matter and that this matter in the large-$N_{\mathrm{c}}$ limit is confined as measured by the interaction between heavy quarks, but behaves in other respects like a quasifree gas of quarks. As a result of the extrapolation to $N_{\mathrm{c}}=3$, we present a revised phase diagram with the SQGB phase bounded by thermal crossovers. Finally, we give a quantitative analysis of chiral-symmetry restoration in the SQGB phase.

Motivated by the recent LHCb Collaboration analysis, we have investigated the process $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$ by considering the contributions from the resonances $Y(4710)$ and $K_0^{*}(1430)$. Our results are in good agreement with the measured invariant mass distributions and the Dalitz plot of LHCb, which supports the existence of the $K_0^{*}(1430)$ and the $Y(4710)$ in the process $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$. Since the decay mode of $Y(4710)\to J/\psi {\eta }^{\prime }$ is Okubo-Zweig-Iizuka suppressed for the charmonium state, the measurements of the $\mathcal{B}(Y(4710)\to J/\psi {\eta }^{\prime })$ through the process $B^{-}\to J/\psi {\eta }^{\prime }{K}^{-}$ or other processes is helpful to understanding the nature of the $Y(4710)$. Thus, we advocate that Belle II and LHCb Collaborations could perform the more precise analysis to confirm the evidence of the $Y(4710)$ state, which could be helpful to reduce the experimental uncertainties of its mass and width and to explore its nature.

Motivated by the BESIII amplitude analysis of the single Cabibbo-suppressed process $D^{+}\to {\pi }^0{\pi }^{+}\eta$, we investigate this reaction by taking into account the contributions from the $a_0(980)$, $\rho$, and $a_0(1710)$, where the scalar meson $a_0(980)$ could be dynamically generated from the $S$-wave pseudoscalar meson-pseudoscalar meson interaction within the chiral unitary approach. Our theoretical predictions for the ${\pi }^0\eta$, ${\pi }^{+}\eta$, and ${\pi }^{+}{\pi }^0$ invariant mass distributions are in agreement with the BESIII measurements, especially the clear peaks around 1 GeV in the ${\pi }^0\eta$ and ${\pi }^{+}\eta$ invariant mass distributions could be associated with the dynamically generated state $a_0(980)$. Furthermore, we demonstrate that the intermediate $a_0(1710)$ is also necessary to describe the enhancement structure around 1.6–1.7 GeV in the ${\pi }^{0/+}\eta$ invariant mass distribution. More precise experimental measurements of this process could provide deeper insights into the nature of the scalar mesons $a_0(980)$ and $a_0(1710)$.

I present the leading 3-loop contributions to the Fermi decay constant in the Standard Model, using the tadpole-free pure $\overline{\mathrm{MS}}$ scheme. The calculation is exact in the limit in which the quantum chromodynamics coupling, the top-quark Yukawa coupling, and the square root of the Higgs self-coupling are all treated as large compared to the electroweak gauge couplings. The effect of the 3-loop contribution is to decrease the estimate of the Higgs vacuum expectation value (VEV), for fixed on-shell inputs, by about 3.5 MeV. The renormalization scale dependence of the computed Fermi constant is greatly reduced compared to the previously known complete 2-loop order result, and as a fraction is now less than $\pm 2\times {10}^{-6}$ for renormalization scales between 90 and 250 GeV. This corresponds to a theoretical uncertainty in the VEV that is well under 1 MeV, and much smaller than the current parametric uncertainties coming mostly from the top-quark mass. I also comment on the impact on the precise prediction of the $W$-boson mass.

Dimuonium (${\mu }^{+}{\mu }^{-}$) is one of the pure QED bound systems of leptons, together with positronium and ditauonium. The former had been observed in an experiment in 1951 [M. Deutsch, Phys. Rev. 82, 455 (1951)], while the search for dimuonium and ditauonium (${\tau }^{+}{\tau }^{-}$) are still in vain. The ditauonium is thought to be hard to measure due to its short life time, whereas the dimuonium is very likely to be observed in current running experiments. We calculate in this work the para and ortho dimuonium production in photon-photon collision at the next-to-leading order (NLO) in QED. To handle the Coulomb divergence within the bound system, the nonrelativistic QED description is adopted for consistency. The results indicate that the NLO corrections are negative for both para and ortho states, at the normal order of perturbative QED corrections. The measurement of the dimuonium in the Belle II experiment, especially at the forthcoming facility of STCF, is tenable.

We study entanglement entropy for slablike regions in quantum field theories, using their holographic duals. We focus on the transition between spacelike and timelike separations. By considering boosted subsystems in conformal and confining holographic backgrounds, we identify two classes of extremal surfaces; real ones (Type I) and complex surfaces (Type II). These interpolate between the usual Ryu-Takayanagi prescription and its timelike generalizations. We derive explicit expressions for the entanglement entropy in both conformal and confining cases and discuss their behavior across phase transitions, and null limits. The interpolation between Type I and Type II surfaces reveals an analytic continuation of the extremal surface across the light cone. Our analysis also finds the existence of a Ryu-Takayanagi surface (Type I) even for timelike separations in the confining field theory case.

Different waveform models can yield notably different conclusions about the properties of individual gravitational wave events. For instance, previous analyses using the seobnrv4phm, imrphenomxphm models, and nrsur7dq4 have led to varying results regarding event properties. This variability complicates the interpretation of the data and understanding of the astrophysical phenomena involved. There is an ongoing need to reassess candidate events with the best available interpretations and models. Current approaches lack efficiency or consistency, making it challenging to perform large-scale reanalyses with updated models or improved techniques. It is imperative that investigations into waveform systematics be reproducible. Frameworks like asimov can facilitate large-scale reanalyses with consistent settings and high-quality results, and can reliably show how different waveform models affect the interpretation of gravitational wave events. This, in combination with other provided tools, allows for reanalysis of several events from the GWTC-3 catalog. We include access to full analysis settings that facilitate public use of GWOSC data on the Open Science Grid, particularly those conducted with the imrphenompv2, seobnrv4phm, seobnrv5phm, and nrsur7dq4 waveform models. Our parameter inference results find similar conclusions to previously published work: for several events, all models largely agree, but for a few exceptional events these models disagree substantially on the nature of the merging binary.

When photons, gravitational waves, and massive particles such as neutrinos are gravitationally lensed the signals detected by telescopes or detectors on and around Earth are usually either magnified or demagnified. However, for stationary and axisymmetric spacetimes conventional methods for calculating the magnification factor usually only allow one to calculate it relative to the spacetime position of the source but not with respect to the source’s reference frame. While this may be sufficient when we want to investigate the properties of the lens, when we want to investigate the source and its properties we need to relate the detected signals to the same signals in the reference frame of their source. In this paper we will now show that for stationary and axisymmetric spacetimes which possess a Carter constant, we can use the constants of motion and the tetrad formalism to derive a magnification factor which relates a signal detected in the reference frame of an observer to the same signal in the reference frame of its source.

Cosmic inflation provides a compelling framework for explaining several observed features of our Universe, but its viability depends on an efficient reheating phase that converts the inflaton’s energy into Standard Model particles. This conversion often proceeds through nonperturbative mechanisms such as parametric resonance, which is described by Hill’s equation. In this work, we investigate how stochastic fluctuations in the parameters of Hill’s equation can influence particle production during reheating. We show that such fluctuations can arise from couplings to light scalar fields and can significantly alter the stability bands in the resonance structure, thereby enhancing the growth of fluctuations and broadening the region of efficient energy transfer. Using random matrix theory and stochastic differential equations, we decompose the particle growth rate into deterministic and noise-induced components and demonstrate analytically and numerically that even modest noise leads to substantial particle production in otherwise stable regimes. These results suggest that stochastic effects can robustly enhance the efficacy of reheating across a wide swath of parameter space, with implications for early Universe cosmology, UV completions involving multiple scalar fields, and the resolution of the cosmological moduli problem.

Neutron stars (NSs), the densest known objects composed of matter, provide a unique laboratory to probe whether strange quark matter is the true ground state of matter. We investigate the range of parameters relevant for the equation of state of strange stars taking into account a quantum chromodynamics (QCD)-informed model. The sampling of the parameter space was performed using quasirandom Latin hypercube sampling, ensuring uniform coverage. The parameters are related to the energy density difference between quark matter and the QCD vacuum, the strength of strong interactions, and the gap parameter for color superconductivity. To restrict them, we incorporate observational constraints on the maximum mass of NSs (from both observations of binary systems and NS mergers), the radii of $1.4M_{\odot }$ NSs [inferred from gravitational wave (GW) and electromagnetic observations], and tidal deformations (from GW170817). Our results indicate that strong quark interactions play a crucial role in the description of NSs, with a minimum deviation of at least 20% from the behavior of free quarks. Additionally, we find that color superconductivity is relevant, and derive a maximum gap parameter reaching approximately 230 MeV for a strange quark mass of 100 MeV. Furthermore, we determine that the surface-to-vacuum energy density jump for quark stars lies within the range (1.1–2.2) ${\rho }_{\mathrm{sat}}$, where ${\rho }_{\mathrm{sat}}\simeq 2.7\times {10}^{14}\mathrm{g}{\mathrm{cm}}^{-3}$ is the nuclear saturation density. As a byproduct of the observational constraints, we find that the radius of a $1.4M_{\odot }$ quark star lies in the range (10.0–12.3) km, while its dimensionless tidal deformability falls within the interval (270–970). In addition, all the above constraints are fully consistent with the small mass and radius inferred electromagnetically for the central compact object XMMU J173203.3-344518 (NS) in the supernova remnant HESS J1731-347, with $M=0.77_{-0.17}^{+0.20}{M}_{\odot }$ and $R=10.40_{-0.78}^{+0.86}\mathrm{km}$. The above results may offer important inputs for studies on quark and, in a complementary way, hybrid stars, serving as parameter references for more detailed investigations into their astrophysical signatures, including tidal deformations, cooling curves, quasinormal modes, and ellipticities. We briefly discuss these implications.

The possible occurrence of a first-order hadron-quark phase transition in neutron-star interiors remains an open question. Whether such a transition can be directly tested with improved observations is a key challenge. Here, we incorporate the latest constraints, especially a new radius measurement by the neutron star interior composition explorer for PSR J0614-3329, into a nonparametric Gaussian process equation of state framework that explicitly includes a first-order transition. We find a Bayes factor of $B\approx 2.3$ when comparing models with and without an explicit phase transition, marginally favoring its presence. At 68% credibility, the transition onset density $n_{\mathrm{PT}}$ is either below $2n_s$ (corresponding to masses $\lesssim 1M_{\odot }$, with density jump $\mathrm{\Delta }n\sim 0.5n_s$) or, more prominently, above $4n_s$ (near the central density of the heaviest neutron star, with $\mathrm{\Delta }n\sim 3n_s$), where $n_s$ represents the nuclear saturation density. In addition, by using symmetry-energy expansion at low densities ($<1.1n_s$), we infer a slope parameter $L={40.2}_{-14.3}^{+19.3}\mathrm{MeV}$, in good agreement with nuclear-experiment values. Intriguingly, $L$ correlates positively with the radius difference between $1.4M_{\odot }$ and $2.0M_{\odot }$ stars.