Joint analysis of the baryon acoustic oscillations (BAOs) measurement by the Dark Energy Spectroscopic Instrument (DESI) first data release, type Ia supernovae (SNe) of the Dark Energy Survey Year 5 (DES5YR) release and cosmic microwave background (CMB) data favors a quintomlike dynamic dark energy model over the standard lambda cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) model at $3.9\sigma$ level (Adame et al. 2024). We confirm the previous finding in the literature that the preference for dynamic dark energy does not rely on the detailed modeling of CMB physics and remains at a similar significance level ($3.2\sigma$) when the full CMB likelihood is replaced by a CMB acoustic-oscillation angle (${\theta }_{\star }$) prior and a baryon abundance (${\mathrm{\Omega }}_b{h}^2$) prior. The computationally efficient ${\theta }_{\star }$ and ${\mathrm{\Omega }}_b{h}^2$ priors allow us to take a frequentist approach by comparing DES5YR SNe and DESI BAO with a large number ($\gtrsim {10}^4$) of Planck-constrained $\mathrm{\Lambda }\mathrm{CDM}$ simulations. We find that $\ge 3.2\sigma$ preference for dynamic dark energy is very rare (occurrence $\mathrm{rate}=0.28\%$) in simulations. When we combine DESI BAO with SN simulations or combine DES5YR SNe with BAO simulations, the occurrence rate of $\ge 3.2\sigma$ preference for dynamic dark energy increases to 1.2% and 4.8%, respectively. These results indicate an internal inconsistency, i.e., a significant tension between $\mathrm{DESI}\mathrm{BAO}+\mathrm{DES}5\mathrm{YR}$ SNe and Planck-constrained $\mathrm{\Lambda }\mathrm{CDM}$ models in both Bayesian and frequentist points of view. Although both DESI BAO and DES5YR SNe contribute to the preference for dynamic dark energy, the contribution from DES5YR SNe is more significant. In the frequentist point of view, even DES5YR SNe alone is in tension with Planck-constrained $\mathrm{\Lambda }\mathrm{CDM}$ models, though in Bayesian point of view this tension is prior dependent and inclusive.

The paradigm of the inflationary universe provides a possible explanation for several observed cosmological properties. In order for such solutions to be successful, the universe must convert the energy stored in the inflaton potential into standard model particles through a process known as reheating. In this paper, we reconsider the reheating process for the case where the inflaton potential respects an approximate (but spontaneously broken) conformal symmetry during the reheating epoch. After reviewing the effective field theory of reheating, we present solutions for the nonlinear oscillations of the inflaton field, derive the corresponding Hill’s equation for the coupled reheating field, and determine the stability diagram for parametric resonance. For this class of models—the simplest realization being a scalar field with a quartic term—the expansion of the Universe drives the coupled field toward a more unstable part of parameter space, in contrast to the standard case. We also generalize this class of models to include quadratic breaking terms in the potential during the reheating epoch and address the process of stability in that universality class of models.

The first high-energy neutrino source identified by IceCube was a blazar—an active galactic nucleus driving a relativistic jet toward Earth. Jets driven by accreting black holes are commonly assumed to be needed for high-energy neutrino production. Recently, IceCube discovered neutrinos from Seyfert galaxies, which appears unrelated to jet activity. Here, we show that the observed luminosity ratios of neutrinos and hard x rays from blazars $\mathrm{TXS}0506+056$ and $\mathrm{GB}6\mathrm{J}1542+6129$ are consistent with neutrino production in a $\gamma$-obscured region near a central supermassive black hole, with the x-ray flux corresponding to reprocessed $\gamma$-ray emission with flux comparable to that of neutrinos. Similar neutrino–hard x-ray flux ratios are found for four Seyfert galaxies, NGC 1068, NGC 4151, CGCG 420-015, and NGC 3079, raising the possibility of a common neutrino production mechanism that may not involve a strong jet.

Dark matter (DM) properties at small scales remain uncertain. Recent theoretical and observational advances have provided the tools to narrow them down. Here, we show for the first time that the correlation between internal velocities and sizes of dwarf galaxies is a sharp probe of small-scale DM properties. We study modified DM power spectra, motivated by DM production during inflation. Using semianalytic models and scaling relations, we show that such models can change the kinematics and structure of dwarf galaxies without strongly affecting their total abundance. We analyze data from Milky Way classical satellite galaxies and those discovered with the Sloan Digital Sky Survey, finding that the DM power spectrum at comoving scales $4{\mathrm{Mpc}}^{-1}<k<37{\mathrm{Mpc}}^{-1}$ cannot deviate by more than a factor of $\sim 2.5$ from scale invariance. Our results are robust against baryonic uncertainties such as the stellar mass-halo mass relation, halo occupation fraction, and subhalo tidal disruption; allowing us to independently constrain them. This work thus opens a window to probe both dwarf galaxy formation models and small-scale DM properties.

We study the corrections to the vacuum energy density occurring in a Casimir apparatus in the framework of two models of nonlinear electrodynamics, namely the ModMax model and the Euler-Heisenberg model. We linearize the two theories around a fixed background magnetic field ${\overrightarrow{B}}_0$, whose lines of force are orthogonal to the metallic plates of a Casimir cavity. We find the dispersion relations of the electromagnetic perturbations $\overrightarrow{e}$ and $\overrightarrow{b}$ behaving as plane waves inside the cavity in the magnetic background, thus computing the vacuum energy density and the strength of the force arising between the plates confining the electromagnetic field. In both models we find a tiny increase in the absolute value of the Casimir energy density, resulting in a small strengthening of the attractive force between the plates. However, in the Euler-Heisenberg model the correction to the energy density and to the attractive force depends quadratically on the intensity of the background magnetic field, while in the ModMax model both energy density and force turn out to be independent of $B_0$, due to the conformal invariance. One may expect that future refined experimental techniques (like those developed in the LIGO and VIRGO interferometers) will allow for accurate measurements of the Casimir force in the presence of magnetic fields of different intensities, thus allowing—in principle—to discriminate between the two considered models.

We investigate the emission of circularly polarized photons from a magnetized quark-gluon plasma with nonzero quark-number and chiral charge chemical potentials. These chemical potentials qualitatively influence the differential emission rates of circularly polarized photons. A nonzero net electric charge density, induced by quark-number chemical potentials, enhances the overall emission of one circular polarization over the other, while a nonzero chiral charge density introduces a spatial asymmetry in the emission with respect to reflection in the transverse plane. The signs of the electrical and chiral charge densities determine which circular polarization dominates overall and whether the emission preferentially aligns with or opposes the magnetic field. Based on these findings, we propose that polarized photon emission is a promising observable for characterizing the quark-gluon plasma produced in heavy-ion collisions.

Historically it has been believed that a time-independent classical source has no effect on the scattering of relativistic uncharged fields, in contrast with single particle quantum mechanics. In this work we show that the dynamics is not trivial. We solve exactly for the scattering amplitudes and find that a key ingredient is the production of particles from the unstable vacuum, conceptually similar to the Schwinger mechanism. We compute exactly the probabilities for the vacuum to decay in $n$ particles. The time dependence of such probabilities displays interesting properties such as the quantum Zeno effect and, in particular, has no regime where the exponential decay law is a good approximation. We show that the trivial scattering found in the past is the by-product of the adiabatic switching of the interaction. In fact, it is not possible to switch off the interaction (adiabatically or otherwise) at distant times and recover the exact results. Finally, this nontrivial vacuum behavior is a source of particle production. We argue that such nonperturbative calculations can be phenomenologically relevant for the production processes that are suppressed at the lower orders in perturbation theory, for instance dilaton production in a medium.

The neutrino oscillation experiments provide definitive evidence of new physics beyond the Standard Model, and the neutrino mass-squared differences and flavor mixing have been precisely measured. This study examines the neutrino sector within the flavor-dependent $U(1{)}_F$ model, where the unique fermion sector can simultaneously address both the flavor mixing puzzle and the mass hierarchy puzzle. It is found that the lightest neutrino is naturally massless in this model, and the predicted neutrino mass-squared differences, flavor mixing angles, and Dirac $CP$ phase agree well with the experimental measurements. Additionally, the effects of the Dirac $CP$ phase and Majorana $CP$ phase on the theoretical predictions of the neutrino transition magnetic dipole moments are analyzed.

We propose a novel leptogenesis mechanism with a temperature-dependent coupling between the right-handed neutrino and Standard Model particles. This coupling experiences suppression at high temperatures and becomes sizable when the lepton asymmetry washout processes are Boltzmann-suppressed. Such a feature ensures that the washout rates remain consistently below the Hubble expansion rate, preserving all lepton asymmetry generated in the decay of right-handed neutrinos. We illustrate the feasibility of this mechanism with two example models and show that the observed baryon asymmetry of the Universe can be successfully obtained for right-handed neutrino masses larger than ${10}^9\mathrm{GeV}$ as well as for smaller violation of charge-parity symmetry.

We propose a novel scenario to obtain the correct relic abundance for thermally underproduced dark matter. This scenario utilizes a strongly first-order phase transition at temperature $T_{\mathrm{PT}}$ that gives rise to dark matter mass $m$. Freeze-out in the broken phase can yield the desired abundance in the entire region currently allowed by observational bounds and theoretical constraints for ${10}^2{T}_{\mathrm{PT}}\lesssim m\lesssim {10}^4{T}_{\mathrm{PT}}$. We show that the accompanying gravitational waves are strong enough to be detected by many upcoming and proposed experiments. This, in tandem with dark matter indirect searches, provides a multimessenger probe of such models. Positive signals in the future can help reconstruct the potential governing the phase transition and shed light on an underlying particle physics realization.

We analyze the exclusive two-body nonleptonic decays of $B_s$ meson to ground as well as radially excited $2S$ charmonium state with a light meson $K_s$, induced by the $b\to c\overline{c}d$ transition. Within the framework of relativistic independent quark model based on a flavor-independent interaction potential in scalar-vector harmonic form, we calculate the weak form factors from the overlapping integrals of meson wave function obtained in this model. Using the factorization approximation, we predict the branching fractions for the $B_s\to \psi (1S,2S)K_s$ and $B_s\to {\eta }_c(1S,2S)K_s$, which can be compared with future theoretical predictions. Branching fraction for $B_s\to J/\psi K_s$ decay is found to be in good agreement with the data from the LHCb collaboration, whereas for $B_s\to \psi (2S)K_s$, it is found to be within the detection ability of the CMS collaboration. We also predict the ratios of branching fractions $(\mathcal{R})$, which are in broad agreement with the data from LHCb collaboration. These results indicate that the present approach works well in the description of exclusive nonleptonic $B_s$ decays within the framework of the relativistic independent quark model.

A consistent action for heterotic and type II superstring field theory was recently proposed by Sen. We give an algebraic formulation of this action in terms of certain twisted $L_{\infty }$ algebra. We further show that Sen’s Wilsonian effective superstring field action can be obtained using homotopy transfer and the effective theory also possesses the algebraic structure of a twisted $L_{\infty }$ algebra.

We compare the effective action of the scale factor obtained from lattice quantum gravity [in the form of causal dynamical triangulations (CDT)] to the corresponding effective action obtained from the simplest functional renormalization group (FRG) calculation. In this way, we can identify the generic infinite four-volume limit of the lattice theory in the so-called de Sitter phase with the Gaussian fixed-point limit or the IR fixed-point limit obtained by FRG. We also show how to identify a putative UV lattice gravity fixed point. Our Monte Carlo simulations of CDT allow for the existence of such a UV fixed point, although the data precision does not yet provide a proof of its existence. The concept of a correlation length relevant for the lattice gravity fixed points is argued to be different from the concept of correlation lengths encountered in field theories in a fixed spacetime background.

A model is proposed for a classical bosonic string in $d=3$ Minkowski space with an action functional that includes Gauss and mean world-sheet curvature. The Lagrangian is invariant under $3d$ Poincaré transformations modulo total divergence. In addition to the diffeomorphism, the action enjoys the extra gauge symmetry with the second derivatives of the scalar gauge parameter. This symmetry gauges out all the local degrees of freedom (d.o.f.), while some global d.o.f. survive. The Hamiltonian constrained analysis confirms that the model does not have any local d.o.f.. The world sheet of the string turns out to be a cylinder with timelike axis. The global d.o.f. of this string describe one single irreducible massive $3d$ particle with spin. The particle momentum is a conserved vector directed along the cylinder axis while the momentum square is a fixed constant determined by the parameters in the action. The total angular momentum is a conserved vector that defines the position of the axis of the cylinder whose specific value is defined by initial data, while the spin, being the product of momentum and angular momentum is fixed by the parameters in the string Lagrangian.

The Newtonian restricted three-body problem involving a positive primary point mass, $m_{+}$, and a negative secondary point mass, $m_{-}$, in a circular orbit, and a positive or negative tertiary point mass, $m_3$, with $m_{+}>|m_{-}|\gg |m_3|$, is solved. Five Lagrange points are found for $m_3$, three of which are coplanar with $m_{+}$ and $m_{-}$, and two of which are not, a subtle consequence of the gravitational repulsion from $m_{-}$. All Lagrange points are linearly unstable, except for one point in the regime $m_{+}\gtrsim 8.4|m_{-}|$, which is linearly stable and collinear with $m_{+}$ and $m_{-}$.

A massive black hole can develop a dark-matter overdensity, and the dark matter changes the evolution of a stellar-mass compact object inspiraling around the massive black hole through the dense dark-matter environment. Specifically, dynamical friction speeds up the inspiral of the compact object and causes feedback on the dark-matter distribution. These intermediate mass-ratio inspirals with dark matter are a source of gravitational waves (GWs), and the waves can dephase significantly from an equivalent system in vacuum. Prior work has shown that this dephasing needs to be modeled to detect the GWs from these systems with LISA (the Laser Interferometer Space Antenna); it also showed that the density and distribution of dark matter can be inferred from a GW measurement. In this paper, we study whether the parametrized post-Einsteinian (ppE) framework can be used to infer the presence of dark matter in these systems. We confirm that if vacuum waveform templates are used to model the GWs from an inspiral in a dark-matter halo, then the resulting parameter estimation is biased. We then apply the ppE framework to determine whether it can reduce the parameter-estimation biases, and we find that adding one ppE phase term to a waveform template eliminates the parameter-estimation biases (statistical errors become larger than the systematic ones), but the effective post-Newtonian order in the ppE framework must be specified without uncertainties. When the post-Newtonian order has uncertainty, we find that the systematic errors on the ppE and the binary’s parameters exceed the statistical errors. Thus, the simplest ppE framework would not give unbiased results for these systems, and a further extension of it, or dedicated parameter estimation with gravitational waveforms that include dark-matter effects would be needed.

In the present work, we have studied the masses and magnetic moments of $\mathrm{spin}-{\frac{1}{2}}^{+}$ and $\mathrm{spin}-{\frac{3}{2}}^{+}$ singly and doubly charmed baryons in the strange hadronic medium at finite temperature using the chiral SU(3) quark mean field model. The properties of baryons within the framework of the chiral SU(3) mean field model are defined in terms of constituent quark masses and energies, which are modified through the exchange of scalar fields $\sigma$, $\zeta$, and $\delta$ and the vector fields $\omega$, $\rho$, and $\varphi$. The scalar-isovector field, $\delta$, and the vector-isovector field, $\rho$, contribute when the medium has finite isospin asymmetry. We have calculated the effective masses of constituent quarks and charmed baryons in the nuclear and strange matter within the chiral SU(3) quark mean field model and have used these as the input in SU(4) constituent chiral quark model to compute the effective magnetic moments of these baryons. Considering the configuration mixing, the contributions of valence quarks, quark sea, and orbital angular momentum of quark sea have been considered explicitly to calculate the in-medium magnetic moments.

We propose the nucleon consumption induced by dark matter (DM) as a new scenario to overcome the energy threshold of direct detection. It can be realized with proton ($\chi +p\to \chi +{\ell }^{+}$) or neutron ($\chi +n\to \chi +\nu$) target. Both effective operators and concrete models are provided to illustrate the idea. Since the initial DM and nucleon velocity is only ${10}^{-3}$ and $1/4$ of the speed of light, respectively, the cross section and hence event rate are determined by the involved particle masses and not affected by the nucleon Fermi motion. Of the two realizations, the proton consumption has richer phenomena with both charged lepton and the daughter nuclei deexcitation to allow double or even triple coincidence to significantly suppress the background. We also illustrate the projected sensitivities at DM and neutrino experiments such as PandaX-4T, DUNE, JUNO, and Hyper-K.

Using $7.93{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ collision data collected at the center-of-mass energy of 3.773 GeV with the BESIII detector, we measure the absolute branching fractions of $D^0\to K^{-}{e}^{+}{\nu }_e$, $D^0\to K^{-}{\mu }^{+}{\nu }_{\mu }$, $D^{+}\to {\overline{K}}^0{e}^{+}{\nu }_e$, and $D^{+}\to {\overline{K}}^0{\mu }^{+}{\nu }_{\mu }$ to be $(3.521\pm 0.009_{\mathrm{stat}}\pm 0.016_{\mathrm{syst}})\%$, $(3.419\pm 0.011_{\mathrm{stat}}\pm 0.016_{\mathrm{syst}})\%$, $(8.864\pm 0.039_{\mathrm{stat}}\pm 0.082_{\mathrm{syst}})\%$, and $(8.665\pm 0.046_{\mathrm{stat}}\pm 0.084_{\mathrm{syst}})\%$, respectively. By performing a simultaneous fit to the partial decay rates of these four decays, the product of the hadronic form factor $f_{+}^K(0)$ and the modulus of the $c\to s$ Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ is determined to be $f_{+}^K(0)|V_{cs}|=0.7171\pm 0.0011_{\mathrm{stat}}\pm 0.0013_{\mathrm{syst}}$. Taking the value of $|V_{cs}|=0.97349\pm 0.00016$ from the standard model global fit or that of $f_{+}^K(0)=0.7452\pm 0.0031$ from the lattice quantum chromodynamics calculation as input, we derive the results $f_{+}^K(0)=0.7366\pm 0.0011_{\mathrm{stat}}\pm 0.0013_{\mathrm{syst}}$. and $|V_{cs}|=0.9623\pm 0.0015_{\mathrm{stat}}\pm 0.0017_{\mathrm{syst}}\pm 0.0040_{\mathrm{LQCD}}$.