If long-range attractive forces exist and are stronger than gravity then cosmic halo formation can begin in the radiation-dominated era. We study a simple realization of this effect in a system where dark matter fermions have Yukawa interactions mediated by scalar particles, analogous to the Higgs boson in the standard model. We develop a self-consistent description of the system including exact background dynamics of the scalar field, and precise modeling of the fermion density fluctuations. For the latter, we provide accurate approximations for the linear growth as well as quantitative modeling of the nonlinear evolution using $N$-body simulations. We find that halo formation occurs exponentially fast and on scales substantially larger than simple estimates predict. The final fate of these halos remains uncertain, but could be annihilation, dark stars, primordial black holes, or even the existence of galaxy-sized halos at matter-radiation equality. More generally, our results demonstrate the importance of mapping scalar-mediated interactions onto structure formation outcomes and constraints for beyond the standard model theories.

We calculate the spin-flavor precession (SFP) of Dirac neutrinos induced by strong magnetic fields and finite neutrino magnetic moments in dense matter. As found in the case of Majorana neutrinos, the SFP of Dirac neutrinos is enhanced by the large magnetic field potential and suppressed by large matter potentials composed of the baryon density and the electron fraction. The SFP is possible irrespective of the large baryon density when the electron fraction is close to $1/3$. The diagonal neutrino magnetic moments that are prohibited for Majorana neutrinos enable the spin precession of Dirac neutrinos without any flavor mixing. With supernova hydrodynamics simulation data, we discuss the possibility of the SFP of both Dirac and Majorana neutrinos in core-collapse supernovae. The SFP of Dirac neutrinos occurs at a radius where the electron fraction is $1/3$. The required magnetic field of the proto-neutron star for the SFP is a few ${10}^{14}\mathrm{G}$ at any explosion time. For the Majorana neutrinos, the required magnetic field fluctuates from ${10}^{13}\mathrm{G}$ to ${10}^{15}\mathrm{G}$. Such a fluctuation of the magnetic field is more sensitive to the numerical scheme of the neutrino transport in the supernova simulation.

We present a variational quantum eigensolver (VQE) algorithm for the efficient bootstrapping of the causal representation of multiloop Feynman diagrams in the loop-tree duality or, equivalently, the selection of acyclic configurations in directed graphs. A loop Hamiltonian based on the adjacency matrix describing a multiloop topology, and whose different energy levels correspond to the number of cycles, is minimized by VQE to identify the causal or acyclic configurations. The algorithm has been adapted to select multiple degenerated minima and thus achieves higher detection rates. A performance comparison with a Grover’s based algorithm is discussed in detail. The VQE approach requires, in general, fewer qubits and shorter circuits for its implementation, albeit with lesser success rates.

We study the origin of the real intermediate state subtraction problem and compare its different solutions. We show that the ambiguity in subtraction schemes arises from the on-shell approximation for the 2-point functions that reduces the Schwinger-Dyson equations to the Boltzmann limit. We also suggest a new subtraction scheme which, unlike the earlier definitions, never leads to negative scattering rates. This scheme also quantifies the validity of the on-shell limit in terms of an effective one-particle weight function $R(\mathrm{\Delta })$, where $\mathrm{\Delta }$ measures the region around the resonance associated with the real state.

The cosmological first-order phase transition (FOPT) can be of strong dynamics, but its bubble wall velocity is difficult to determine due to the lack of detailed collision terms. Recent holographic numerical simulations of strongly coupled theories with an FOPT prefer a relatively small wall velocity linearly correlated with the phase pressure difference between false and true vacua for a planar wall. In this article, we analytically reveal the nonrelativistic limit of a planar/cylindrical/spherical wall expansion of a bubble strongly interacting with the thermal plasma. The planar-wall result reproduces the linear relation found previously in the holographic numerical simulations. The results for cylindrical and spherical walls can be directly tested in future numerical simulations. Once confirmed, the bubble wall velocity for a strongly coupled FOPT can be expressed purely in terms of the hydrodynamics without invoking the underlying microphysics.

In this paper, we propose a new method for measuring the Sachs form factors ratio ($R={\mu }_p{G}_E/G_M$) based on the transfer of polarization from the initial proton to the final electron in the elastic $e\overrightarrow{p}\to \overrightarrow{e}p$ process, in the case when the axes of quantization of spins of the target proton at rest and of the scattered electron are parallel, i.e., when an electron is scattered in the direction of the spin quantization axis of the proton target. To do this, in the kinematics of the SANE Collaboration experiment [A. Liyanage et al., Phys. Rev. C 101, 035206 (2020).] on measuring double-spin asymmetry in the $\overrightarrow{e}\overrightarrow{p}\to ep$ process, using Kelly [Phys. Rev. C 70, 068202 (2004).] and Qattan et al. [Phys. Rev. C 91, 065203 (2015).] parametrizations, a numerical analysis was carried out of the dependence of the longitudinal polarization degree of the scattered electron on the square of the momentum transferred to the proton, as well as on the scattering angle of the electron. It is established that the difference in the longitudinal polarization degree of the final electron in the case of conservation and violation of scaling of the Sachs form factors can reach 70%. This fact can be used to set up polarization experiments of a new type to measure the ratio $R$.

We point out a dark matter candidate that arises in a minimal extension of solutions to the hierarchy problem based on compositeness. In such models, some or all of the Standard Model fields are composites of a conformal field theory (CFT), which confines near the electroweak scale. We posit an elementary scalar field, whose mass is expected to lie near the cutoff of the CFT and whose couplings to the Standard Model are suppressed by the cutoff. Hence, it can naturally be ultraheavy and feebly coupled. This scalar can constitute all of the dark matter for masses between ${10}^{10}\mathrm{GeV}$ and ${10}^{18}\mathrm{GeV}$, with the relic abundance produced by the freeze-in mechanism via a coupling to the CFT. The principal experimental constraints come from bounds on the tensor-to-scalar ratio. We speculate about future detection prospects.

We examine dark matter, neutrino magnetic moment, and mass in a Type-III radiative scenario. The Standard Model is enriched with three vectorlike fermion triplets and two inert doublets to provide a suitable platform for the above phenomenological aspects. The inert scalars contribute to the total relic density of dark matter in the Universe. Neutrino aspects are realized at one loop with the magnetic moment obtained through charged scalars, while the neutrino mass gets contributions from charged and neutral scalars. Taking inert scalars up to 2 TeV and triplet fermions in the few hundred TeV range, we obtain a common parameter space, compatible with experimental limits associated with both neutrino and dark matter sectors. Using a specific region for the transition magnetic moment [$\mathcal{O}({10}^{-11}{\mu }_B)$], we explain the excess recoil events, reported by the XENON1T Collaboration. Finally, we demonstrate that the model is able to provide neutrino magnetic moments in a wide range from ${10}^{-12}{\mu }_B$ to ${10}^{-10}{\mu }_B$, meeting the bounds of various experiments such as Super-K, TEXONO, Borexino, and XENONnT.

We present a lattice calculation of the low energy constants of QCD with $N_c=3$, 4 and 5 colors and $N_f=2$ flavors of degenerate mass fermions. We fit data for the pseudoscalar meson mass, the pseudoscalar decay constant, and the axial Ward identity fermion mass to formulas from next-to-next-to leading order chiral perturbation theory. We extract the next to leading order low energy constants and study their behavior as a function of $N_c$. Preexisting analyses of $N_c=3$ inform our fitting strategies.

In this paper, we present lattice QCD results for the $x$ dependence of the unpolarized gluon parton distribution functions (PDFs) for the proton. We use one ensemble of $N_f=2+1+1$ maximally twisted mass fermions with a clover improvement, and the Iwasaki improved gluon action. The quark masses are tuned to produce a pion with a mass of 260 MeV. The ensemble has a lattice spacing of $a=0.093\mathrm{fm}$ and a spatial extent of 3 fm. We employ the pseudodistribution approach, which relies on matrix elements of nonlocal operators that couple to momentum-boosted hadrons. In this work, we use five values of the momentum boost between 0 and 1.67 GeV. The gluon field-strength tensors of the nonlocal operator are connected with straight Wilson lines of varying length $z$. The light-cone Ioffe time distribution (ITD) is extracted utilizing data with $z$ up to 0.56 fm and a quadratic parametrization in terms of the Ioffe time at fixed values of $z$. We explore systematic effects, such as the effect of the stout smearing for the gluon operator, excited states effects, and the dependence on the maximum value of $z$ entering the fits to obtain the gluon PDF. Also, for the first time, the mixing with the quark singlet PDFs is eliminated using matrix elements with nonlocal quark operators that were previously analyzed within the quasi-PDF framework on the same ensemble. Here, we expand the dataset for the quark singlet and reanalyze within the pseudo-PDFs method eliminating the corresponding mixing in the gluon PDF.

We extend our relativistic theory of gravitational structure of composite hadrons to obtain the pion gravitational form factors at large momentum transfers. The approach was used in the case of intermediate region of the variable in our preceding works [Phys. Rev. D 103, 014029 (2021)] and [Phys. Rev. D 106, 054013 (2022)]. The calculation is carried out in the framework of a relativistic composite-particle model complemented by the special relativistic form of impulse approximation. It is found that in the limit of massless and pointlike quarks, the obtained asymptotic expansion coincides with the predictions of perturbative QCD for gravitational pion form factors. The principal contribution to the asymptotics, coinciding with the predictions of QCD, is given by the relativistic effect of spin rotation. In particular, the asymptotics of the $D$ form factor is completely determined by this kinematic effect. Several restrictions on the allowed form of gravitational form factors of quarks are derived.

We study the inhomogeneous phase of a two-flavor quark matter under rotation at finite temperature and density using the Nambu-Jona-Lasinio model. To do this, we consider the chiral broken phase, in particular, described by the so-called dual chiral density wave which is formed as a standing wave of simultaneous scalar and pseudoscalar condensates. The solution of the corresponding Dirac equation as well as the energy spectrum found in the mean-field approximation. We then use the thermodynamic potential calculated for this model, to study the $\mu$ and $\mathrm{\Omega }$ dependence of constituent mass and the wave vector at $T=0$. We find there exist two islands in the $\mu -\mathrm{\Omega }$ plane that the dual-chiral density wave survives. The first region lies at intermediate densities and small $\mathrm{\Omega }$. We observe, by increasing the angular velocity of matter, dual-chiral density wave forms in regions with smaller chemical potential. On the other hand, in contrast to the former, the second region is located at the large $\mathrm{\Omega }$ and small densities. Finally, we study this phase of quark matter at finite temperature and present $T-\mu$, $T-\mathrm{\Omega }$, and $\mu -\mathrm{\Omega }$ phase portraits of a hot-rotating quark matter at finite density.

There are three types of fragmentation functions (FFs) which are used to describe the twist-3 cross sections of the hard semi-inclusive processes under QCD collinear factorization, and they are called intrinsic, kinematical, and dynamical FFs. In this work, we investigate the theoretical relations among these FFs for a tensor-polarized spin-1 hadron. Three Lorentz-invariance relations are derived by using the identities between the nonlocal quark-quark and quark-gluon-quark operators, which guarantee the frame independence of the twist-3 spin observables. The QCD equation of motion relations are also presented for the tensor-polarized FFs. In addition, we show that the intrinsic and kinematical twist-3 FFs can be decomposed into the contributions of twist-2 FFs and twist-3 three-parton FFs, and the latter are also called dynamical FFs. If one neglects the dynamical FFs, we can obtain relations which are analogous to the Wandzura-Wilczek relation. Then, the intrinsic and kinematical twist-3 FFs are expressed in terms of the leading-twist ones. Since the FFs of a spin-1 hadron can be measured at various experimental facilities in the near future, these theoretical relations will play an important role in the analysis of the collinear tensor-polarized FFs.

We present a detailed investigation on the intrinsic charm content in a light meson within the ’t Hooft model, namely, two-dimensional QCD in the large-$N_c$ limit. The intrinsic charm parton distribution function (PDF) of a light meson, which first arises at order $N_c^{-1}$, is explicitly expressed in terms of the ’t Hooft wave functions of the light meson and an infinite tower of excited charmed mesons. We also derive the functional forms of the two-dimensional counterparts of the meson cloud model and Brodsky-Hoyer-Peterson-Sakai model. We then make a quantitative comparison between our results and model predictions. We also study how the profile of the intrinsic charm PDF varies with charm-quark mass. The average momentum fraction carried by the charm quark inside a light meson is found to decrease as $m_c^{-6}$ in the heavy charm quark mass limit.

We determine the Cabibbo-Kobayashi-Maskawa matrix-element magnitude $|V_{cb}|$ using ${\overline{B}}^0\to D^{*+}{\ell }^{-}{\overline{\nu }}_{\ell }$ decays reconstructed in $189{\mathrm{fb}}^{-1}$ of collision data collected by the Belle II experiment, located at the SuperKEKB $e^{+}{e}^{-}$ collider. Partial decay rates are reported as functions of the recoil parameter $w$ and three decay angles separately for electron and muon final states. We obtain $|V_{cb}|$ using the Boyd-Grinstein-Lebed and Caprini-Lellouch-Neubert parametrizations, and find $|V_{cb}{|}_{\mathrm{BGL}}=(40.57\pm 0.31\pm 0.95\pm 0.58)\times {10}^{-3}$ and $|V_{cb}{|}_{\mathrm{CLN}}=(40.13\pm 0.27\pm 0.93\pm 0.58)\times {10}^{-3}$ with the uncertainties denoting statistical components, systematic components, and components from the lattice QCD input, respectively. The branching fraction is measured to be $\mathcal{B}({\overline{B}}^0\to D^{*+}{\ell }^{-}{\overline{\nu }}_{\ell })=(4.922\pm 0.023\pm 0.220)\%$. The ratio of branching fractions for electron and muon final states is found to be $0.998\pm 0.009\pm 0.020$. In addition, we determine the forward-backward angular asymmetry and the $D^{*+}$ longitudinal polarization fractions. All results are compatible with lepton-flavor universality in the Standard Model.

The process $e^{+}{e}^{-}\to \omega {\pi }^0\to {\pi }^{+}{\pi }^{-}{\pi }^0{\pi }^0$ is studied in the center-of-mass energy region 1.05–2.00 GeV using data with an integral luminosity of about $35{\mathrm{pb}}^{-1}$ collected with the SND detector at the VEPP-2000 $e^{+}{e}^{-}$ collider. In the energy range under study, the value of the measured Born cross section varies from 0.7 to 18 nb. The statistical uncertainty of the cross section is 2%–23%, while the systematic uncertainty is in the range of 3.0%–14.2%. The results are consistent with previous measurements but have better accuracy.

It was shown that the Lie algebra underlying higher-spin holography admits a contraction including a Poincaré subalgebra in any space-time dimensions. The associated curvatures, however, do not reproduce upon linearization those that are usually employed to formulate the equations of motion of free massless particles in Minkowski space. We show that, despite this mismatch, the new linearized curvatures can also be used to describe massless higher-spin fields. This suggests a new way to build interacting higher-spin gauge theories in Minkowski space that may admit a holographic description.

We show that viable electroweak baryogenesis can be realized without a first-order phase transition if plasma is heated inhomogeneously by nongravitational structure formation in some particle species. Yukawa interactions can mediate relatively long-range attractive forces in the early Universe. This creates an instability and leads to growth of structure in some species even during the radiation dominated era. At temperatures below the electroweak scale, the collapsing and annihilating halos can heat up plasma in fireballs that expand and create the out-of-equilibrium high-temperature environment suitable for generating the baryon asymmetry. The plasma temperature at the time of baryogenesis can be as low as a few MeV, making it consistent with both standard and low-reheat cosmologies.

Based on a dynamical model on particle production, the production and fraction of exotic components in neutron star matter are analyzed. It is found that there exists a small fraction of strangeness in twice saturation density matter. For five times saturation density matter, the fraction of strange baryons can be as high as 25%–50%, depending on the equation of state used. The neutron-proton asymmetry of dense matter does not significantly impact the strangeness fraction in neutron star matter. This research provides new insights into the strange components in neutron stars.

Given a model for self-dual nonlinear electrodynamics in four spacetime dimensions, any deformation of this theory which is constructed from the duality-invariant energy-momentum tensor preserves duality invariance. In this work we present new proofs of this known result and also establish a previously unknown converse: any parametrized family of duality-invariant Lagrangians, all constructed from an Abelian field strength $F_{\mu \nu }$ but not its derivatives, is related by a generalized stress tensor flow, in a sense which we make precise. We establish this and other properties of stress tensor deformations of theories of nonlinear electrodynamics using both a conventional Lagrangian representation and using two auxiliary field formulations. We analyze these flows in several examples of duality-invariant models including the Born-Infeld and ModMax theories, and we derive a new auxiliary field representation for the two-parameter family of ModMax-Born-Infeld theories. These results suggest that the space of duality-invariant theories may be characterized as a subspace of theories of electrodynamics with the property that all tangent vectors to this subspace are operators constructed from the stress tensor.