We investigate the transverse energy-energy correlator (TEEC) event-shape observable for back-to-back $\gamma +h$ and $Z+h$ production in both $pp$ and $pA$ collisions. Our study incorporates nuclear modifications into the transverse-momentum dependent (TMD) factorization framework, with resummation up to next-to-leading logarithmic accuracy, for TEEC as a function of the variable $\tau =(1+\cos \varphi )/2$, where $\varphi$ is the azimuthal angle between the vector boson and the final hadron. We analyze the nuclear modification factor $R_{pA}$ in $p\mathrm{Au}$ collisions at Relativistic Heavy Ion Collider and $p\mathrm{Pb}$ collisions at the Large Hadron Collider. Our results demonstrate that the TEEC observable is a sensitive probe for nuclear modifications in TMD physics. Specifically, the changes in the $\tau$-distribution shape provide insights into transverse momentum broadening effects in large nuclei, while measurements at different rapidities allow us to explore nuclear modifications in the collinear component of the TMD parton distribution functions in nuclei.

We study radiation by a fast particle in a medium with a finite chiral chemical potential. The medium’s anomalous response encompasses the chiral magnetic effect, enabling novel chiral Cherenkov and pair production processes. The kinematics of the corresponding cascades is fundamentally different from conventional cascades. Notably, it is not dominated by the strong ordering of momenta. Employing the effective Chern-Simons extensions of QED and QCD to incorporate the chiral magnetic effect, we derive and solve the evolution equations describing the cascades in a chiral medium, presuming that the anomalous contributions are dominant.

The chiral bag model offers a dual description of hadron physics in terms of quarks and hadrons in the sense of Cheshire Cat principle. In this work, we find that, within the chiral bag, confinement is likely caused by monopole condensation. The chiral bag surface can be interpreted as an ${\eta }^{\prime }$ domain wall, where a dynamical Chern-Simons theory emerges. Under level-rank duality, the Chern-Simons theory serves as the counterterm introduced to block the so-called color charge leakage. To ensure the correct net baryon number of the full chiral bag, an additional Chern-Simons theory involving the vector meson field arises on the bag surface and extends outside the bag. This leads to a Chern-Simons-Higgs theory localized on the ${\eta }^{\prime }$ domain wall, as previously conjectured. We also propose that the skyrmion description of baryons could be understood as a system of monopoles enveloped by a meson cloud.

Quantum information methods have been brought to bear on high-energy physics, including the study of entanglement and Bell nonlocality in collider experiments. Quantum information observables have also been employed to constrain possible new-physics effects. We improve on this point by introducing quantum information tools routinely used to compare quantum states: the trace distance and the fidelity. We find that the former outperforms other quantum information observables considered in the literature and, together with the cross section, yields the strongest bounds on possible departures from the Standard Model. The power of the proposed methodology is demonstrated with three examples of new-physics searches. The first concerns the chromomagnetic dipole moment of the top quark and yields the first bound computed by means of quantum tomography and actual experimental data. The other two examples use Monte Carlo simulations and set the projected limits on the anomalous couplings of the $\tau$ leptons at Belle and at a future collider—which is taken to be LEP3. For these new-physics searches, we also compare the sensitivity of the trace distance to those of other quantum information quantities like concurrence, magic, and the fidelity distance. In passing, we provide the first determinations of magic in collider data by analyzing the top-quark pair production at the LHC and the charmonium decays. The significance is well above the $5\sigma$ level in both the cases.

New physics beyond the Standard Model (SM) may appear in the form of nonstandard neutrino interactions (NSIs). We have studied neutral current (anti)neutrino-nucleon scattering in presence of NSIs. We obtain that in this scenario, nucleon matrix elements depend not only on the isovector axial nucleon form factor but also on the isoscalar one. For the axial form factors we consequently rely on the quark flavor decomposition performed by QCD simulations in the lattice (LQCD). We have examined cross sections and polarization observables. For the current bounds on diagonal muon flavor NSI couplings, we find substantial deviations from the SM predictions in cross sections and transverse polarizations of the outgoing nucleons. In view of the progress in the precision of LQCD determinations of nucleon properties, modern measurements of neutral current (anti)neutrino-nucleon scattering will be in the position to discover or significantly constrain NSIs.

We study the direct $CP$ asymmetries in the decays of $B^0\to {\mathrm{\Xi }}_c^{+}{\overline{\mathrm{\Xi }}}_c^{-}$ and $B_s^0\to {\mathrm{\Lambda }}_c^{+}{\overline{\mathrm{\Lambda }}}_c^{-}$, emphasizing the critical role of final-state interactions (FSIs). In these channels, the small energy release and annihilation topology suppress short-distance contributions while enhancing long-distance effects. By separating the decay amplitudes into S and P waves, we show that the P-wave component, carrying only a single weak phase, contributes negligibly to $CP$ asymmetries. In contrast, the S-wave amplitude—strongly modified by FSIs—acquires a substantial strong phase that enables interference among multiple weak phases, producing large $CP$-violating effects. Numerically, we find sizable asymmetries of $a_{CP}^{\mathrm{dir}}=0.88\pm 0.05\pm 0.10$ for $B^0\to {\mathrm{\Xi }}_c^{+}{\overline{\mathrm{\Xi }}}_c^{-}$ and $a_{CP}^{\mathrm{dir}}=-0.106\pm 0.019\pm 0.010$ for $B_s^0\to {\mathrm{\Lambda }}_c^{+}{\overline{\mathrm{\Lambda }}}_c^{-}$, where the first and second uncertainties stem from the poorly known hadron couplings and the omission of the $B^0\to K^{+}{K}^{-}\to {\mathrm{\Xi }}_c^{+}{\overline{\mathrm{\Xi }}}_c^{-}$ rescattering process. For practical feasibility, we restrict our analysis to intermediate states involving pseudoscalar mesons, which yield tractable loop integrals. Excited intermediate states, such as $D^{(*)}{\overline{D}}^{(*)}$, are omitted because their inclusion would require handling nonrenormalizable interactions, introducing substantial ambiguity. These results, combined with the relatively large branching fractions, make these modes prime targets for experimental searches at LHCb and Belle II, potentially offering new insights into strong dynamics and nonperturbative QCD in heavy-hadron decays.

We present measurements of total neutron production from atmospheric neutrino interactions in water, analyzed as a function of electron-equivalent visible energy over a range of 30 MeV to 10 GeV. These results are based on 4,270 days of data collected by Super-Kamiokande, including 564 days with 0.011 wt% gadolinium added to enhance neutron detection. Neutron signal selection is based on a neural network trained on simulation, with its performance validated using an Am/Be neutron point source. The measurements are compared to predictions from neutrino event generators combined with various hadron-nucleus interaction models, which include an intranuclear cascade model and a nuclear deexcitation model. We observe significant variations in the predictions depending on the choice of hadron-nucleus interaction model. We discuss key factors that contribute to describing our data, such as in-medium effects in the intranuclear cascade and the accuracy of statistical evaporation modeling.

The STAR Collaboration reports precise measurements of the longitudinal double-spin asymmetry, $A_{LL}$, for dijet production with at least one jet at intermediate pseudorapidity $0.8<{\eta }_{\text{jet}}<1.8$ in polarized proton-proton collisions at a center-of-mass energy of 200 GeV. This study explores partons scattered with a longitudinal momentum fraction ($x$) from 0.01 to 0.5, which are predominantly characterized by interactions between high-$x$ valence quarks and low-$x$ gluons. The results are in good agreement with previous measurements at 200 GeV with improved precision and are found to be consistent with the predictions of global analyses that find the gluon polarization to be positive. In contrast, the negative gluon polarization solution from the JAM Collaboration is found to be strongly disfavored.

Is the standard model charge-parity ($CP$) violation ever enough to generate the observed baryon asymmetry? Yes! We introduce a mechanism of baryogenesis (and dark matter production) that can generate the entire observed baryon asymmetry of the Universe using only the $CP$ violation within standard model systems—a feat which no other mechanism currently proposed can achieve. Baryogenesis proceeds through a mesogenesis scenario but with well motivated additional dark sector dynamics: a morphon field generates present day mass contributions for the particle mediating the decay responsible for baryogenesis. The effect is an enhancement of baryon production while evading present day collider constraints. The $CP$ violation comes entirely from standard model contributions to neutral meson systems. Meanwhile, the dark dynamics generate gravitational waves that may be searched for with current and upcoming pulsar timing arrays, as we demonstrate with an example potential that is tuned to generate domain walls that annihilate later. This mechanism, mesogenesis with a morphing mediator, motivates probing a new parameter space as well as improving the sensitivity of existing mesogenesis searches at hadron and electron colliders.

Local operators are the basic observables in quantum field theory which encode the physics observed by a local experimentalist. However, when gravity is dynamical, diffeomorphism symmetries are gauged which apparently obstruct a sensible definition of local operators, as different locations in spacetime are connected by these gauged symmetries. This consideration brings in the puzzle of reconciling our empirical world with quantum gravity. Intuitively, this puzzle can be avoided using relatively defined observables when there exists a natural reference system such as a distribution of galaxies in our Universe. Nevertheless, this intuition is classical as the rods and clock defined in this way may also have quantum fluctuations, so it is not a priori clear if it can be realized in the quantum regime. In this paper, we provide an affirmative answer to this question. Interestingly, we notice that the quantum fluctuations of the reference system are in fact essential for the realization of the above intuition in the quantum regime.

In this work, we present a geometrical reconstruction of the critical points of the spinfoam amplitude for a 4D Lorentzian model with a nonzero cosmological constant. By establishing the correspondence between the moduli space of $\mathrm{SL}(2,\mathbb{C})$ flat connections on the graph-complement 3-manifold $S^3\backslash {\mathrm{\Gamma }}_5$ and the geometry of a constantly curved 4-simplex, we demonstrate how the critical points encode discrete curved geometries. The analysis extends to 4-complexes dual to colored graphs, aligning with the improved spinfoam model recently introduced in Han and Pan [Complex Chern-Simons theory with $k=8\mathbb{N}$ and an improved Spinfoam model with cosmological constant, Phys. Rev. D 111, DD13861 (2025).]. Central to this reconstruction are translating the geometry of constantly curved 4-simplices into Fock-Goncharov coordinates and spinors, which translate the geometry data into holonomies and symplectic structures, thereby defining the critical points of the spinfoam amplitude. This framework provides an algorithmic foundation for computing quantum gravity corrections and opens avenues for applications in quantum cosmology and black hole physics, where the cosmological constant plays a pivotal role.

We derive the explicit embedding of the effective Kerr spacetimes, which are pertinent to the vanishing of static Love numbers, soft hair descriptions of Kerr black holes, and low-frequency scalar-Kerr scattering amplitudes, as solutions within $N=2$ supergravity. These spacetimes exhibit a hidden $SL(2,R)\times U(1)$ or $SO(4,2)$ symmetry resembling the so called subtracted geometries with $SL(2,R)\times SL(2,R)$ symmetry, which accurately represent the near-horizon geometry of Kerr black holes and, as we will argue most accurately represents the internal structure of the Kerr black hole. To quantify the differences among the effective Kerr spacetimes, we compare their physical quantities, internal structures, and geodesic equations. Although their thermodynamic properties, including entropy, match those of Kerr, our study uncovers significant differences in the interiors of these effective Kerr solutions. A careful examination of the internal structure of the spacetimes highlights the distinctions between various effective Kerr geometries and their quasinormal spectra.

We suggest a dynamical mechanism which explains why, in the supersymmetric Ishibashi-Kawai-Kitazawa-Tsuchiya matrix model, the $SO(9)$ symmetry of the Lagrangian is spontaneously broken to $SO(3)\times SO(6)$, allowing only three large classical spatial dimensions to emerge. The argument relies on the identification of D-strings as stable excitations of the matrices about the cosmological background and the absence of forces between parallel D-string excitations. A spatial dimension can only become large if the D-strings winding in that direction can annihilate. In the absence of forces, this requires the string-world sheets to intersect, a process which is highly suppressed if more than three dimensions of space are large. Implications for a recently proposed matrix cosmology scenario are discussed.

The loop quantum gravitational collapse of a dust ball in the presence of positive cosmological constant is investigated within the Oppenheimer-Snyder collapse scenario. The dust ball interior is described within the framework of loop quantum cosmology, while its exterior geometry is determined by the differentiability of the spacetime metric at the dust ball surface and the assumption of the (vacuum) exterior to be stationary. In order to determine the global causal structure of the investigated spacetime a robust (numerical) method of constructing Penrose-Carter diagrams is built. Unfortunately, the presence of a cosmological constant does not cure the problems already present in the case of it vanishing; the exterior geometry resembles that of the Reissner-Nordström-de Sitter black hole, in particular featuring timelike singularties.

We present exact results in softly broken supersymmetric $\mathrm{SU}(N_C)$ chiral gauge theories with charged fermions in one antisymmetric, $N_F$ fundamental, and $N_C+N_F-4$ antifundamental representations. We achieve this by considering the supersymmetric version of these theories and utilizing anomaly mediated supersymmetry breaking at a scale $m\ll \mathrm{\Lambda }$ to generate a vacuum. The connection to nonsupersymmetric theories is then conjectured in the limit $m\to \infty$. For odd $N_C$, we determine the massless fermions and unbroken global symmetries in the infrared. For even $N_C$, we find global symmetries are nonanomalous and no massless fermions. In all cases, the symmetry breaking patterns differ from what the tumbling hypothesis would suggest.

Nonlinear tails in black hole perturbations, arising from second-order effects, present a distinct departure from the well-known Price tail of linear theory. We present an analytical derivation of the power law indices and amplitudes for nonlinear tails stemming from outgoing sources, and validate these predictions to percent-level accuracy with numerical simulations. We then perform a perturbative analysis on the dynamical formation of nonlinear tails in a self-interacting scalar field model, wherein the nonlinear tails are sourced by a $\lambda {\mathrm{\Phi }}^3$ cubic coupling. Due to cascading mode excitations and back-reactions, nonlinear tails with $t^{-l-1}$ power law are sourced in each harmonic mode, dominating the late time behavior of the scalar perturbations. In verification, we conducted numerical simulations of the self-interacting scalar model, including all real spherical harmonic (RSH) with $l\le 4$ and their respective nonlinear couplings. We find general agreement between the predicted and numerical power law indices and amplitudes for the nonlinear tails, with the exception of $l=4$ modes, which display $t^{-4}$ power law instead of the predicted $t^{-5}$. This discrepancy is due to distortion in the source of the tails, which is caused by another nonlinear effect. These results establish nonlinear tails as universal features of black hole dynamics, with implications for gravitational wave astronomy: they may imprint observable signatures in merger remnants, offering novel probes of strong-field gravity and nonlinear mode couplings.

In this work, we study the problem of generalizing the Gibbons-Hawking-York boundary terms for general quadratic theories of gravity and propose a simple condition to obtain them. From these terms, we derive the junction conditions for a subset of this family of theories that includes Gauss-Bonnet (GB) gravity. We reobtain the well-known results for GB theory, generalize them to other quadratic theories, and compare the resulting junction conditions with the ones already derived in the literature using other methods.

According to Albert Einstein, gravitation is analogous to an optical medium. Building on this idea, various definitions of the gradient-index (GRIN) medium representing curved spacetime have been proposed; often, these approaches demand advanced knowledge of general relativity (GR) and its associated mathematical methods. This paper introduces an alternative approach for generating the form of GRIN media that reproduces the exact behavior of photon trajectories in the presence of a Schwarzschild black hole or about the equatorial plane of a Kerr black hole. Our approach is based on Noether’s theorem that leads to the optical Fermat principle, leveraging the system’s symmetry, resulting in an unrestricted and robust method for finding GRIN media in a flat spacetime that reproduces the behavior of null geodesics in Schwarzschild-like spacetimes, employing only photon trajectories as input. This approach is also valid for massive particles and provides a complementary understanding of GR. For this reason, the method is applied to generate the GRIN medium from the S2 star’s trajectory around SgrA*, demonstrating that sufficient precision can be achieved to reproduce the orbit’s subtle apsidal precession.

The upcoming gravitational-wave (GW) observatory LISA will measure the parameters of sources like extreme-mass-ratio inspirals (EMRIs) to exquisite precision. These measurements will also be sensitive to perturbations to the vacuum, GR-consistent evolution of sources, which might be caused by astrophysical environments or deviations from general relativity (GR). Previous studies have shown such “beyond-vacuum-GR” perturbations to potentially induce severe biases ($\gtrsim 10\sigma$) on recovered parameters under the “null” vacuum-GR hypothesis. While Bayesian inference can be performed under the null hypothesis using Markov-chain Monte Carlo (MCMC) samplers, it is computationally infeasible to repeat for more than a modest subset of all possible beyond-vacuum-GR hypotheses. We introduce bias-corrected importance sampling, a generic inference technique for nested models that is informed by the null hypothesis posteriors and the linear signal approximation to correct any induced inference biases. For a typical EMRI source that is significantly influenced by its environment but has been inferred only under the null hypothesis, the proposed method efficiently recovers the injected (unbiased) source parameters and the true posterior at a fraction of the expense of redoing MCMC inference under the full hypothesis. In future GW data analysis, using the output of the proposed LISA global-fit pipeline, such methods may be necessary for the feasible and systematic inference of beyond-vacuum-GR effects.

We investigate the non-Gaussianity of second-order matter density perturbations induced by primordial gravitational waves (GWs). These tensor induced scalar modes arise from local fluctuations in the GW energy density, which is quadratic in tensor perturbations. The resulting second-order density contrast follows a $\chi$-squared distribution, naturally exhibiting significant non-Gaussianity. We compute the bispectrum of these tensor induced scalar modes and analyze its dependence on various primordial GW power spectra, including scale-invariant, blue-tilted, Gaussian-bump, and monochromatic sources. We find that the bispectrum shape is inherently sensitive to the underlying GW spectrum by construction. In particular, Gaussian-bump and monochromatic sources produce a strong signal peaking in the equilateral configuration that is similar to the effect of scalar induced tensor modes. Our findings reveal a new way to probe primordial GWs via galaxy surveys and highlight a unique feature of tensor induced density perturbations, otherwise mimicking linear ones on subhorizon scales.