Lattice studies of the doubly charm tetraquark $T_{cc}=cc\overline{u}\overline{d}$ require the determination of the $D{D}^{*}$ scattering amplitude, which most often incorporate only meson-meson interpolators. We additionally incorporate diquark-antidiquark operators and find that these have some impact on certain eigenenergies. This study presents the first extraction of the $D{D}^{*}$ scattering amplitude based on the meson-meson as well as diquark antidiquark interpolators. The effect of the additional operators renders slightly smaller values of $p$ $\cot {\delta }_0$ and a $T_{cc}$ pole slightly closer to the threshold. The scattering amplitude is extracted from eigenenergies by adopting plane-wave and effective-field-theoretic methods, which also incorporate the left-hand cut and address the partial wave mixing. The $T_{cc}$ is found to be a subthreshold resonance with a pole at $m_{T_{cc}}-m_D-m_{D^{*}}=-{5.2}_{-0.8}^{+0.7}-i·{6.3}_{-4.8}^{+2.4}\mathrm{MeV}$, employing coordinated lattice simulations (CLS) ensembles with $m_{\pi }\simeq 280\mathrm{MeV}$ and the distillation method. A more significant effect of diquark-antidiquark operators on eigen-energies is found for larger heavy quark masses relevant for $T_{bb}$. We find that deeply bound $T_{bb}$ does not emerge when employing only meson-meson operators, where each meson is separately momentum projected, while the deeply bound state emerges after adding local diquark antidiquark operators.

We evaluate the phase-space integrals that arise in double real emission diagrams for semi-inclusive deep-inelastic scattering at next-to-next-to-leading order in QCD. Utilizing the reverse unitarity technique, we convert these integrals into loop integrals, allowing us to employ integration-by-parts identities and reduce them to a set of master integrals. The master integrals are then solved using the method of differential equations and expressed in terms of Goncharov polylogarithms. By examining the series expansion in the dimensional regulator, we discover additional relations among some of the master integrals. As an alternative approach, we solve the master integrals by decomposing them into angular and radial components. The angular parts are evaluated using Mellin-Barnes representation, while special attention is given to the singular structures of the radial integrals to handle them accurately. Here the results are provided in terms of one-fold integrals over classical polylogarithms. This approach provides a clearer understanding of the origin of soft and collinear singularities.

We investigate the properties of charmonium systems in strong external magnetic fields using a relativistic light-front Hamiltonian approach within the basis light-front quantization framework. By solving the eigenvalue problem for the invariant mass squared operator with confinement potentials and one-gluon-exchange interactions, we obtain the mass spectrum and wave functions under varying magnetic fields. Our results reveal significant spectral modifications through the Zeeman effect, including ${\eta }_c\text{−}J/\psi$ mixing and magnetic sublevel splitting. Momentum density analysis demonstrates wave function deformation, with transverse momentum broadening and longitudinal narrowing under strong fields, alongside structural shifts in parton distributions such as double-hump profiles in excited states. Relativistic corrections and center-of-mass coupling critically drive these dynamics, highlighting the necessity of a relativistic framework for QCD bound states in extreme magnetic environments.

Within the basis light-front quantization framework, we systematically investigate the unpolarized and longitudinally polarized double parton distributions (DPDs) of quarks inside the proton. We utilize the light-front wave functions of the proton derived in the valence sector from a Hamiltonian quantized on the light front. The interaction terms of the Hamiltonian consist of a one-gluon exchange interaction at fixed coupling and a three-dimensional confinement potential. Our current analysis yields significant correlations of the quarks’ longitudinal momenta with their transverse separation. We also demonstrate that our calculations do not support the commonly used $x-{\overrightarrow{k}}_{\perp }$ factorization of the DPDs in $x$ and $k_{\perp }$. Our results are qualitatively consistent with those of other phenomenological models.

In ultrarelativistic collisions of nuclei at the Large Hadron Collider, the created QCD environment rapidly changes, leading to a nonadiabatic evolution of the quantum states involved. Considering this, we first examine the preequilibrium state of QCD matter and its effect on the initially produced charmonium using a temperature-independent Hamiltonian. As the QCD matter reaches local thermal equilibrium, this Hamiltonian transforms to its finite temperature counterpart. To model the preequilibrium stage, we use the bottom-up thermalization approach to determine the effective temperature of the QCD matter, followed by a Gubser-type expansion for the thermalized medium. Additionally, we consider collisional damping, gluonic dissociation, and regeneration mechanisms, which specifically modify the charmonium yield in the thermalized medium. Mainly, the gluonic dissociation and collisional damping cause a reduction in the yield conversely, regeneration through gluonic deexcitation enhances the yield of charmonium. Further, we explore the combined effects of these mechanisms on the collective yield of charmonium states with transverse momentum ($p_{\mathrm{T}}$) and event multiplicity in the proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$. Based on our findings, we contend that the combined effects of these mechanisms can serve as a robust probe for determining the possible existence of a thermalized QCD medium in such a small collision system.

The proton’s internal structure is characterized not only by its charge and magnetic distribution, but also by its mechanical and mass properties, which are encoded in the energy-momentum tensor (EMT) of quantum chromodynamics (QCD). These properties provide insights into the spatial distributions of energy, pressure, and shear forces within the proton. Understanding the proton’s internal structure, including properties such as its mechanical and mass radii, is essential for unraveling the complex interplay between quarks and gluons that govern its stability and dynamics. In this study, we investigate the gravitational form factors (GFFs) of the proton, particularly the D term, which encodes key information about the internal stress distribution, pressure, and shear forces within the nucleon. Using a model for skewness-dependent generalized parton distributions constructed from the double-distribution representation, we extract the quark contribution to the $D(t)$ GFF of the EMT by analyzing available data on Compton form factors. We then employ this extracted GFF to explore the mechanical properties of the proton, including its mechanical and mass radii, as well as the internal pressure and shear force distributions. Our results provide new insights into the proton’s internal structure and contribute to the broader understanding of nucleon properties.

Both positive and negative charge conjugation glueball spectra are computed with a constituent gluon approach. We first compute the spectrum of the Hamiltionian describing two-gluon bound states having $C=+$, before tackling the three-gluon bound states having $C=-$. We review the construction of two and three particle helicity states in order to build totally symmetric wave functions for our glueball states. In the literature, two different couplings schemes are used to build three particle states. We derive for the first time the relation between these two three-body state definitions. The glueball spectra are compared with those obtained from quantum chromodynamics simulations on a lattice. The two-gluon glueball spectra show a good agreement with the constituent approach and the numerical lattice simulations. The three-gluon spectrum is in overall agreement with the masses observed on the lattice but also predicts additional low-lying states.

As in previous decades, a comprehensive understanding of the intricate internal configuration of hadrons continues to be a central objective within both experimental and theoretical hadron physics. This pursuit plays a pivotal role in advancing our knowledge of quantum chromodynamics (QCD) and critically evaluating the robustness and accuracy of the theoretical models developed to date. Furthermore, deciphering the underlying mechanisms of exotic states, both those currently observed and those anticipated in future experiments, remains a pressing and unresolved challenge. Motivated by this, in the present study, we investigate the electromagnetic properties of the $D{\overline{D}}_1(2420)$ and $D^{*}{\overline{D}}^{*}(2400)$ molecular tetraquark states with quantum numbers $J^{PC}=1^{--}$, using the QCD light-cone sum rule method. These states are analyzed within a hadronic molecular framework, where their magnetic and quadrupole moments are computed to probe internal structure and geometric deformation. Our results reveal distinct electromagnetic signatures, with the magnetic moments primarily dominated by light-quark contributions, and the quadrupole moments suggesting an oblate charge distribution. The findings are compared with prior studies assuming compact tetraquark configurations, emphasizing the sensitivity of electromagnetic observables to the underlying hadronic structure. This analysis provides critical insights into the nature of exotic hadrons and contributes to the broader understanding of QCD dynamics in the nonperturbative regime.

We present an updated global analysis of beauty decays sensitive to the angle $\gamma$ of the Cabibbo-Kobayashi-Maskawa matrix and of $D$-meson mixing data in the framework of approximate universality, in which $CP$ violation in $D-\overline{D}$ mixing is described in terms of two universal weak phases corresponding to dispersive and absorptive contributions. We extract the fundamental theoretical parameters determining absorptive and dispersive contributions to $D$ meson mixing and $CP$ violation, together with the angle $\gamma$. The results for the charm mixing parameters are $x_{12}\simeq x=(0.401\pm 0.043)\%$ and $y_{12}\simeq y=(0.610\pm 0.017)\%$, while the two $CP$-violating phases are given by ${\varphi }_2^M=(0.13\pm 0.70)°$ and ${\varphi }_2^{\mathrm{\Gamma }}=(2.1\pm 1.6)°$. The angle $\gamma$ is found to be $\gamma =(65.7\pm 2.5)°$, in excellent agreement with the indirect determination from the unitarity triangle analysis.

By analyzing $(2712.4\pm 14.3)\times {10}^6\psi (3686)$ events collected with the BESIII detector operating at the BEPCII collider, the decays ${\chi }_{c0,1,2}\to 3K_S^0{K}^{\pm }{\pi }^{\mp }$ are observed for the first time with statistical significances greater than $10\sigma$. The branching fractions of these decays are determined to be $\mathcal{B}({\chi }_{c0}\to 3K_S^0{K}^{\pm }{\pi }^{\mp })=(7.95\pm 0.50\pm 0.65)\times {10}^{-5}$, $\mathcal{B}({\chi }_{c1}\to 3K_S^0{K}^{\pm }{\pi }^{\mp })=(2.62\pm 0.08\pm 0.19)\times {10}^{-4}$, and $\mathcal{B}({\chi }_{c2}\to 3K_S^0{K}^{\pm }{\pi }^{\mp })=(1.72\pm 0.07\pm 0.15)\times {10}^{-4}$, where the first uncertainties are statistical and the second systematic.

We measure the time-integrated $CP$ asymmetry, $A_{CP}$, in $D^0\to {\pi }^0{\pi }^0$ decays reconstructed in $e^{+}{e}^{-}\to c\overline{c}$ events collected by Belle II during 2019–2022. The data corresponds to an integrated luminosity of $428{\mathrm{fb}}^{-1}$. The $D^0$ decays are required to originate from the flavor-conserving $D^{*+}\to D^0{\pi }^{+}$ decay to determine the charm flavor at production time. Control samples of $D^0\to K^{-}{\pi }^{+}$ decays, with or without an associated pion from a $D^{*+}$ decay, are used to correct for detection asymmetries. The result, $A_{CP}(D^0\to {\pi }^0{\pi }^0)=(0.30\pm 0.72\pm 0.20)\%$, where the first uncertainty is statistical and the second systematic, is consistent with $CP$ symmetry.

A search for cascade decays of charged sleptons and sneutrinos using final states characterized by three leptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on a dataset with $140{\mathrm{fb}}^{-1}$ of proton-proton (pp) collisions at a center-of-mass energy of $\sqrt{s}=13\mathrm{TeV}$ recorded by the ATLAS detector at the Large Hadron Collider. This paper focuses on a supersymmetric scenario that is motivated by the muon anomalous magnetic moment observation, dark-mattter relic density abundance, and electroweak naturalness. A mass spectrum involving light Higgsinos and heavier sleptons with a bino at intermediate mass is targeted. No significant deviation from the Standard Model expectation is observed. This search enables us to place stringent constraints on this model, excluding at the 95% confidence level charged slepton and sneutrino masses up to 450 GeV when assuming a lightest neutralino mass of 100 GeV and mass-degenerate selectrons, smuons and sneutrinos.

I demonstrate that soft graviton modes in de Sitter spacetimes are the Goldstone modes of the spontaneously broken asymptotic symmetry group of de Sitter space. I then show that any local measurement, including the effects of the environment, will collapse the symmetric state onto the broken state in the large volume limit. In any discussion involving observers, de Sitter spacetimes are, therefore, best described globally by the broken phase, while local observers, in the small volume limit, can not discriminate between different degenerate global vacuum states and are therefore best described by the symmetric state. As a consequence, a small Hubbled-sized local region initially in the symmetric state will, after a time-scale corresponding to the Page time of de Sitter space, have expanded to a large region in the broken state. This illuminates the physical nature of soft graviton modes in de Sitter spacetimes.

We introduce the concept of “ajar systems” as an intermediate case between closed and open systems, where the time scale for charge exchange with the environment is parametrically larger than all other characteristic time scales. The Schwinger-Keldysh effective action for such finite-temperature systems exhibits a symmetry group $G_1\times G_2$ weakly broken to its diagonal subgroup $G_{\mathrm{diag}}$, which we systematically describe using spurion techniques. For $G=U(1)$, we calculate leading-order corrections to correlation functions in both diffusive and spontaneously broken phases. Unlike systems with approximate symmetries where both real and imaginary parts of dispersion relations receive corrections, ajar systems modify only the imaginary part—preserving gapless modes while adding finite damping.

In this study, we investigate the imaginary potential of heavy quarkonium in the spinning black hole background. Then, we estimate the thermal width, which is determined by the imaginary part of the finite-temperature potential. In the ultralocal description, the boosted fluid represents a globally rotating fluid. Using a holographic approach, we systematically analyze how the boost parameter influences these quantities. Our results reveal that increasing the boost parameter causes the imaginary potential to emerge at smaller interquark distances, suggesting that the boost parameter accelerates quarkonium melting. Furthermore, we find that the boost parameter enhances the thermal width, indicating greater instability of the bound state at higher boost parameter values. Notably, we observe that the effect of the boost parameter on quarkonium dissociation is more pronounced when the axis of the quark-antiquark pair is transverse to the direction of the boost parameter.

Is bipartite entanglement sufficient for holography? Through the analysis of the Markov gap, it is known that the answer is no. In this paper, we give a new perspective on this issue from a different angle using a multientropy. We define a genuine $\mathtt{q}$-partite multientropy from a $\mathtt{q}$-partite multientropy by subtracting appropriate linear combinations of $\tilde{\mathtt{q}}$-partite multientropies for $\tilde{\mathtt{q}}<\mathtt{q}$, in such a way that the genuine $\mathtt{q}$-partite multientropy vanishes for all $\tilde{\mathtt{q}}$-partite entangled states. After studying several aspects, we apply it to black holes and holography. For the application to black holes, we see that such a genuine $\mathtt{q}$-partite multientropy is important only after the Page time. For the application to holography, we prove that nonbipartite multientropies are always positive and $\mathcal{O}(1/G_N)$, as long as boundary subregions are connected. This indicates that for holography, genuine multipartite entanglement is not small and plays an important role.

We explore the time-dependent Casimir-Polder-like quantum gravitational interaction between a nonpointlike object and a gravitational Dirichlet boundary, i.e., the dynamical gravitational Casimir-Polder interaction, based on the theory of linearized quantum gravity. We demonstrate that the dynamical interaction potential is nonzero prior to the radiation, which is generated by the gravitational vacuum-fluctuation-induced mass quadrupole of the object, being reflected by the gravitational boundary and backreacted to the object (i.e., the mirror image of the object lies outside its causal region). This indicates the nonlocality of the fluctuating gravitational field in vacuum and calls for a reevaluation of the inherent causality within the interaction. Moreover, the dynamical gravitational Casimir-Polder interaction can be either attractive or repulsive depending on the distance of the object with respect to the boundary and the time of interaction. When the interaction time is sufficiently long for the system to approach asymptotic equilibrium, the dynamical gravitational Casimir-Polder interaction potential reduces to the static one, which is time-independent and consistently repulsive in both the near and far regimes.

We develop a systematic framework for analyzing time-ordered perturbative expansions in quantum field theory (QFT) applicable to stationary spacetimes with a timelike Killing vector field. Focusing on the interaction between a scalar field and multiple Unruh-DeWitt detectors undergoing uniform acceleration, we employ the global Killing time to synchronize interactions and consistently implement the Dyson expansion. Our formalism prevents causality-violating errors that arise from a naive treatment of time-ordering for detectors with differing proper times and accelerations. Using light-cone coordinates and explicit parametrizations of the detector worldlines, we construct and classify all relevant interaction terms up to the third order for a two-detector system. This provides a clear and unambiguous foundation for calculating higher-order S-matrix contributions and investigating phenomena such as entanglement harvesting.