The cosmic microwave background (CMB) lensing power spectrum is a powerful probe of the late-time Universe, encoding valuable information about cosmological parameters such as the sum of neutrino masses and dark energy equation of state. However, the presence of anisotropic cosmic birefringence can bias the reconstructed CMB lensing power spectrum using CMB polarization maps, particularly at small scales, and affect the constraints on these parameters. Upcoming experiments, which will be dominated by the polarization lensing signal, are especially susceptible to this bias. We identify the dominant contribution to this bias as an $N_L^{(1)}$-like noise, caused by anisotropic rotation instead of lensing. We show that, for an CMB-S4-like experiment, a scale-invariant anisotropic rotation field with a standard deviation of 0.05 degrees can suppress the small-scale lensing power spectrum ($L\gtrsim 2000$) at a comparable level to the effect of massive neutrino with ${\sum }_i{m}_{{\nu }_i}=50\mathrm{meV}$, making rotation field an important source of degeneracy in neutrino mass measurement for future CMB experiments. We provide an analytic expression and a simulation-based estimator for this $N_L^{(1)}$-like noise, which allows for efficient forecasting and mitigation of the bias in future experiments. Furthermore, we investigate the impact of a non-scale-invariant rotation power spectrum on the reconstructed lensing power spectrum and find that an excess of power in the small-scale rotation power spectrum leads to a larger bias. Our work provides an effective numeric framework to accurately model and account for the bias caused by anisotropic rotation in future CMB lensing measurements.

We construct a hybrid-inflation model where the inflaton potential is generated radiatively, as gauge symmetries guarantee it to be accidentally flat at tree level. The model can be regarded as a small-field version of natural inflation, with inflation ending when the mass of a second scalar, the waterfall field, turns tachyonic. This provides a minimal, robust realization of hybrid inflation, which predicts specific correlations among cosmic microwave background observables. Tachyonic preheating leads to the production of gravitational waves which, for a low inflationary scale, might be detected by upcoming experiments. Simple variations of the model can give rise to topological defects, such as unstable domain walls. Their dynamics produces a stochastic gravitational-wave background, which can be compatible with the recent detection by pulsar timing arrays.

Dark matter (DM) constitutes the predominant portion of matter in our Universe. Despite compelling evidence, the precise characteristics of DM remain elusive. Among the leading DM candidates are weakly interacting massive particles, which may clump into steep concentrations around the central black holes of galaxies. However, DM profiles of the resulting dense spikes remain uncertain. Here we employ the relativistic dynamics in Schwarzschild geometry and first evaluate the velocity distributions of DM within such spikes. Through variations in black hole masses and dark halo parameters, we identify universal features in DM profiles and fit them with Gaussian distributions. Additionally, we illustrate the impact of dynamical friction on gravitational waves generated by extreme-mass-ratio inspirals within DM spikes, taking into account the velocity distribution of DM in the relativistic regime. Our findings demonstrate the phase shifts in the time-domain waveform, potentially providing useful insights for probing DM in galactic centers by gravitational-wave experiments.

We present a stacked lensing analysis of 96 galaxy clusters selected by the thermal Sunyaev-Zel’dovich (SZ) effect in maps of the cosmic microwave background (CMB). We select foreground galaxy clusters with a $5\sigma$-level SZ threshold in CMB observations from the Atacama Cosmology Telescope, while we define background source galaxies for the lensing analysis with secure photometric redshift cuts in Year 3 data of the Subaru Hyper Suprime Cam survey. We detect the stacked lensing signal in the range of $0.1<R[h^{-1}\mathrm{Mpc}]<100$ in each of three cluster redshift bins, $0.092<z\le 0.445$, $0.445<z\le 0.695$, and $0.695<z\le 1.180$, with 32 galaxy clusters in each bin. The cumulative signal-to-noise ratios of the lensing signal are 14.6, 12.0, and 6.6, respectively. Using a halo-based forward model, we then constrain statistical relationships between the mass inferred from the SZ observation (i.e. SZ mass) and the total mass derived from our stacked lensing measurements. At the average SZ mass in the cluster sample ($2.1-2.4\times {10}^{14}{h}^{-1}{M}_{\odot }$), our likelihood analysis shows that the average total mass differs from the SZ counterpart by a factor of $1.3\pm 0.2$, $1.6\pm 0.2$, and $1.6\pm 0.3$ (68%) in the aforementioned redshift ranges, respectively. Our limits are consistent with previous lensing measurements, and we find that the cluster modeling choices can introduce a $1\sigma$-level difference in our parameter inferences.

We employ first-principles quantum field theoretical methods to investigate the longitudinal and transverse electrical conductivities of a strongly magnetized hot quantum electrodynamics (QED) plasma at the leading order in coupling. The analysis employs the fermion damping rate in the Landau-level representation, calculated with full kinematics and exact amplitudes of one-to-two and two-to-one QED processes. In the relativistic regime, both conductivities exhibit an approximate scaling behavior described by ${\sigma }_{\parallel ,\perp }=T{\tilde{\sigma }}_{\parallel ,\perp }$, where ${\tilde{\sigma }}_{\parallel ,\perp }$ are functions of the dimensionless ratio $|eB|/T^2$ (with $T$ denoting temperature and $B$ magnetic field strength). We argue that the mechanisms for the transverse and longitudinal conductivities differ significantly, leading to a strong suppression of the former in comparison to the latter.

We describe a novel class of quantum mechanical particle oscillations in both relativistic and nonrelativistic systems based on $\mathcal{P}\mathcal{T}$ symmetry and ${\mathcal{T}}^2=-1$ (relevant for fermions), where $\mathcal{P}$ is parity and $\mathcal{T}$ is time reversal. The Hamiltonians are chosen at the outset to be self-adjoint with respect to a $\mathcal{P}\mathcal{T}$ inner product. The quantum mechanical time evolution is based on a modified $\mathcal{C}\mathcal{P}\mathcal{T}$ inner product constructed in terms of a suitable $\mathcal{C}$ operator. The resulting quantum mechanical evolution is shown to be unitary and probability is conserved by the oscillations.

We present a calculation of the vector-isovector timelike form factors of the pion and the kaon using lattice quantum chromodynamics. We calculate two-point correlation functions with $m_{\pi }\sim 280\mathrm{MeV}$, extracting both the finite-volume spectrum and matrix elements for these states created from the vacuum by a vector current. After determining the coupled-channel $\pi \pi ,K\overline{K}$ scattering amplitudes, we perform the necessary correction for the significant finite-volume effects present in the current matrix elements, leading to the timelike form factors. We find these to be dominated by the presence of the $\rho$ resonance, and we extract its decay constant by an analytic continuation of the amplitudes to the resonance pole. In addition, the spacelike pion form factor is determined on the same lattice configurations, and a dispersive parametrization is used to simultaneously describe the spacelike and elastic timelike regions.

We consider three-dimensional (3D) lattice $\mathrm{SU}(N_c)$ gauge Higgs theories with multicomponent ($N_f>1$) degenerate scalar fields and $U(N_f)$ global symmetry, focusing on systems with $N_c=2$, to identify critical behaviors that can be effectively described by the corresponding 3D $\mathrm{SU}(N_c)$ gauge Higgs field theory. The field-theoretical analysis of the RG flow allows one to identify a stable charged fixed point for large values of $N_f$, that would control transitions characterized by the global symmetry-breaking pattern $\mathrm{U}(N_f)\to \mathrm{SU}(2)\otimes \mathrm{U}(N_f-2)$. Continuous transitions with the same symmetry-breaking pattern are observed in the SU(2) lattice gauge model for $N_f\ge 30$. Here we present a detailed finite-size scaling analysis of the Monte Carlo data for several large values of $N_f$. The results are in substantial agreement with the field-theoretical predictions obtained in the large-$N_f$ limit. This provides evidence that the $\mathrm{SU}(N_c)$ gauge Higgs field theories provide the correct effective description of the 3D large-$N_f$ continuous transitions between the disordered and the Higgs phase, where the flavor symmetry breaks to $\mathrm{SU}(2)\otimes \mathrm{U}(N_f-2)$. Therefore, at least for large enough $N_f$, the 3D $\mathrm{SU}(N_c)$ gauge Higgs field theories with multicomponent scalar fields can be nonperturbatively defined by the continuum limit of lattice discretized models with the same local and global symmetries.

In this work, we investigate the resonance production in ${\mathrm{\Lambda }}_c^{+}\to \gamma {\pi }^{+}\mathrm{\Lambda }$ decay through the triangle singularity (TS) mechanism, within an effective Lagrangian approach. We find that the appropriate loop decay process could develop a triangle singularity in the invariant mass $M_{\pi \mathrm{\Lambda }}$ around 1.35 GeV, with the shape depending on the quantum numbers of ${\mathrm{\Sigma }}^{*}$ states that couple to the final $\pi \mathrm{\Lambda }$ system. Especially, the $\mathrm{\Sigma }(1380)1/2^{-}$ state newly predicted in the pentaquark model, if exists, significantly enhances the TS contribution and sharpens the TS peak due to the $S$-wave ${\mathrm{\Sigma }}^{*}\pi \mathrm{\Sigma }$ vertex in the loop. Therefore, the existence of the $\mathrm{\Sigma }(1380)1/2^{-}$ state can be examined by measuring the TS signal in ${\mathrm{\Lambda }}_c^{+}\to \gamma {\pi }^{+}\mathrm{\Lambda }$. Considering also possible tree-level diagrams, we additionally obtain the branching ratio $\text{Br}({\mathrm{\Lambda }}_c^{+}\to \gamma {\pi }^{+}\mathrm{\Lambda })\simeq 1.5\times {10}^{-5}$. We suggest the investigation of this reaction by future BESIII, LHCb, and Belle experiments.

We investigate the thermodynamics and phase structure of $SU(3)$ Yang-Mills theory on ${\mathbb{T}}^2\times {\mathbb{R}}^2$ in Euclidean spacetime in an effective-model approach. The model incorporates two Polyakov loops along two compactified directions as dynamical variables, and is constructed to reproduce thermodynamics on ${\mathbb{T}}^2\times {\mathbb{R}}^2$ measured on the lattice. The model analysis indicates the existence of a novel first-order phase transition on ${\mathbb{T}}^2\times {\mathbb{R}}^2$ in the deconfined phase, which terminates at critical points that should belong to the two-dimensional $Z_2$ universality class. We argue that the interplay of the Polyakov loops induced by their cross-term in the Polyakov-loop potential is responsible for the manifestation of the first-order transition.

We refine our previous calculation of multipole amplitude $E_{0+}$ for pion photoproduction process, $\gamma N\to \pi N$. The treatment of final-state interactions is based upon an earlier analysis of pion-nucleon scattering within Hamiltonian effective field theory, supplemented by incorporating contributions from the $N^{*}(1650)$ and the $K\mathrm{\Lambda }$ coupled channel. The contribution from the bare state corresponding to the $N^{*}(1650)$ significantly enhances our results. Additionally, we also compute the multipole amplitude $M_{1-}$, which is of direct relevance to the Roper resonance. The results are comparable with other dynamical coupled-channel models, even though the contribution from the bare state (interpreted as a $2s$ excitation) in this channel is small because of its large mass.

We investigate hidden charm pentaquark states using an off-shell coupled-channel formalism involving heavy meson and singly heavy baryon scattering. Our approach utilizes an effective Lagrangian to construct the kernel amplitudes, which respect both heavy quark symmetry and hidden local symmetry. After solving the coupled integral equations, we obtain the transition amplitudes for $J/\psi N$ scattering and various heavy meson and singly heavy baryon scattering processes. We identify seven distinct peaks related to molecular states of heavy mesons $\overline{D}$ (${\overline{D}}^{*}$) and singly heavy baryons ${\mathrm{\Sigma }}_c$ (${\mathrm{\Sigma }}_c^{*}$). Four of these peaks can be associated with the known $P_{c\overline{c}}$ states: $P_{c\overline{c}}(4312)$, $P_{c\overline{c}}(4380)$, $P_{c\overline{c}}(4440)$, and $P_{c\overline{c}}(4457)$. We predict two additional resonances with masses around 4.5 GeV, which we interpret as ${\overline{D}}^{*}{\mathrm{\Sigma }}_c^{*}$ molecular states, and identify one cusp structure. Additionally, we predict two $P$-wave pentaquark states with positive parity, which may be candidates for genuine pentaquark configurations. Notably, these pentaquark states undergo significant modifications in the $J/\psi N$ elastic channel, with some even disappearing due to interference from the positive parity channel. The present investigation may provide insight into the absence of pentaquark states in $J/\psi$ photoproduction observed by the GlueX Collaboration.

The conventional wisdom in dealing with electromagnetic transition between heavy quarkonia is the multipole expansion, when the emitted photon has a typical energy of order quarkonium binding energy. Nevertheless, in the case when the energy carried by the photon is of order typical heavy quark momentum, the multipole expansion doctrine is expected to break down. In this work, we apply the “hard-scattering” approach originally developed to tackle the strongly hindered magnetic dipole ($M1$) transition [Y. Jia et al., Phys. Rev. D 82, 014008 (2010)] to the strongly hindered electric dipole ($E1$) transition between heavy quarkonia. We derive the factorization formula for the strongly hindered $E1$ transition rates at the lowest order in velocity and ${\alpha }_s$ in the context of the nonrelativistic QCD, and conduct a detailed numerical comparison with the standard predictions for various bottomonia and charmonia $E1$ transition processes.

We rigorously prove that, in any relativistic kinetic theory whose nonhydrodynamic sector has a finite gap, the Taylor series of all hydrodynamic dispersion relations has a finite radius of convergence. Furthermore, we prove that, for shear waves, such radius of convergence cannot be smaller than $1/2$ times the gap size. Finally, we prove that the nonhydrodynamic sector is gapped whenever the total scattering cross section (expressed as a function of the energy) is bounded below by a positive nonzero constant. These results, combined with well-established covariant stability criteria, allow us to derive a rigorous upper bound on the shear viscosity of relativistic dilute gases.

Using a data sample of $e^{+}{e}^{-}$ collisions corresponding to an integrated luminosity of $7.93{\mathrm{fb}}^{-1}$ collected with the BESIII detector at the center-of-mass energy 3.773 GeV, we perform the first amplitude analysis of the decay $D^{+}\to K_S^0{K}_S^0{\pi }^{+}$. The absolute branching fraction of $D^{+}\to K_S^0{K}_S^0{\pi }^{+}$ is measured to be $(2.97\pm 0.09_{\mathrm{stat}}\pm 0.05_{\mathrm{syst}})\times {10}^{-3}$. The dominant intermediate process is $D^{+}\to K_S^0{K}^{*}(892{)}^{+}$, whose branching fraction is determined to be $(8.72\pm 0.28_{\mathrm{stat}}\pm 0.15_{\mathrm{syst}})\times {10}^{-3}$, including all the $K^{*}(892{)}^{+}$ decays.

In this work, the Coulomb effects (Coulomb correlations) in ${\pi }^{+}{\pi }^{-}$ pairs produced in $\mathrm{p}+\mathrm{Ni}$ collisions at $24\mathrm{GeV}/c$, are studied using experimental ${\pi }^{+}{\pi }^{-}$ pair distributions in $Q$, the relative momentum in the pair center-of-mass system (c.m.s.), and its projections $Q_L$ (longitudinal component) and $Q_t$ (transverse component) relative to the pair direction in the laboratory system (LS). The major part of the pion pairs (“Coulomb pairs”) is produced in the decay of $\rho$, $\omega$ and $\mathrm{\Delta }$ resonances and other short-lived sources. In these pairs, the significant Coulomb interaction occurs at small $Q$, dominating the ${\pi }^{+}{\pi }^{-}$ interaction in the final state. The minor part of the pairs (“non-Coulomb pairs”) is produced if one or both pions arose from long-lived sources like $\eta ,{\eta }^{\prime }$ or from different interactions. In this case, the final state interaction is practically absent. The $Q$, $Q_L$, and $Q_t$ distributions of the Coulomb pairs in the c.m.s. have been simulated assuming they are described by the phase space modified by the known point-like Coulomb correlation function $A_C(Q)$, corrected for small effects due to the nonpointlike pair production and the strong two-pion interaction. The same distributions of non-Coulomb pairs have been simulated according to the phase space, but without $A_C(Q)$. In all $Q_t$ intervals, the experimental $Q_L$ spectrum shows a peak around $Q_L=0$ caused by the Coulomb final state interaction. The full width at half maximum increases with $Q_t$ from $3\mathrm{MeV}/c$ for $0<Q_t<0.25\mathrm{MeV}/c$ to $11\mathrm{MeV}/c$ for $4.0<Q_t<5.0\mathrm{MeV}/c$. The experimental $Q_L$ distributions have been fitted with two free parameters: the fraction of Coulomb pairs and the normalization constant. The precision of the description of these distributions is better than 2% in $Q_t$ intervals 2–3, 3–4, and $4–5\mathrm{MeV}/c$ and better than 0.5% in the total $Q_t$ interval $0–5\mathrm{MeV}/c$. It is shown that the number of Coulomb pairs in all $Q_t$ intervals, including the small $Q_t$ (small opening angles $\theta$ in the LS) is calculated with theoretical precision better than 2%. The comparison of the simulated and experimental numbers of Coulomb pairs at small $Q_t$ allows us to check and correct the detection efficiency for the pairs with small $\theta$ (0.06 mrad and smaller). It is shown that Coulomb pairs can be used as a new physical tool to check and correct the quality of the simulated events. The special property of the Coulomb pairs is the possibility of checking and correcting the detection efficiency, especially for the pairs with small opening angles.

We report an improved measurement of the valence $u$ and $d$ quark distributions from the forward-backward asymmetry in the Drell-Yan process using $8.6{\mathrm{fb}}^{-1}$ of data collected with the D0 detector in $p\overline{p}$ collisions at $\sqrt{s}=1.96$. This analysis provides the values of new structure parameters that are directly related to the valence up and down quark distributions in the proton. In other experimental results measuring the quark content of the proton, $d$ quark contributions are mixed with those from other quark flavors. In this measurement, the $u$ and $d$ quark contributions are separately extracted by applying a factorization of the QCD and electroweak portions of the forward-backward asymmetry.

It was shown recently that extended black hole thermodynamics, where the cosmological constant is a dynamical variable, giving rise to a pressure $p$ and its conjugate volume $V$, can be given a natural setting in the context of braneworld models. We study the specific heat capacities $C_p(T)$ and $C_V(T)$ of the quantum version of the Bañados, Teitelboim, and Zanelli (BTZ) black hole that lives in the induced gravity theory on the brane. There are multiple branches of solutions, and we explore and characterize key features of the possible behavior. We identify and study a critical point in the space of solutions where both specific heats diverge. In the regime of weak backreaction where we are close to an ordinary theory of gravity, the black hole is “subentropic,” but as backreaction is increased we note that there are parts of parameter space that has regions where it is “superentropic.” While a study of the sign of the specific heats does not always show a corresponding instability (conjectured in the literature), the presence of strong backreaction makes interpretation unclear.