Using a full resummation of the Adler function in the large-${\beta }_0$ approximation of QCD and a mathematical framework of resurgence suitable for the specific properties of the Borel transform in this particular case, we derive a compact resurgent representation of the QCD Adler function, valid in the whole complex momentum plane. The representation is expressed in terms of the inverse Mellin transform of the Borel function and is analytic in the complex momentum plane, except for cuts along the timelike axis and the Landau region of the spacelike axis. It contains a purely nonperturbative term singular at the origin of the coupling plane, depending on a single real arbitrary constant. We compare the resurgent Adler function derived in this work with a previous determination in a similar framework and use its values in the complex plane for a calculation of the hadronic width of the $\tau$ lepton in the Standard Model.

We study the thermoelectric response of a hot and magnetized QCD medium created in the noncentral events at heavy-ion collider experiments. The collisional aspects of the medium have been embedded in the relativistic Boltzmann transport equation (RBTE) using the Bhatnagar-Gross-Krook (BGK) collision integral, which insures the particle number conservation, unlike the commonly used relaxation time approximation (RTA). We have incorporated the thermal medium effects in the guise of a quasiparticle model, where the interaction among the quarks and gluons is assimilated in the medium dependent masses of the quarks, which have been evaluated using imaginary-time formalism of thermal QCD with a background magnetic field. In the absence of $B$, the Seebeck coefficient for individual quark flavors gets slightly reduced in the BGK term in comparison to naive RTA, while it gets enhanced for the composite partonic medium. In the strong magnetic field ($B$), the BGK term enhances the Seebeck coefficient for the individual flavors, as well as that for the medium. The medium Seebeck coefficient rises with the strength of quark chemical potential ($\mu$) in the absence, as well as that in the strong $B$. We observe chirality dependence in the transport coefficients in the weak $B$ as the masses of chiral modes become nondegenerate. In the case of the $L$ modes, the BGK collision term causes a slight reduction in the Seebeck coefficient, while for $R$ modes both the collision integrals produce the same results. The Nernst coefficient gets reduced (enhanced) for $L$ ($R$) chiral modes in the BGK term.

We propose a novel mechanism to generate sterile neutrinos ${\nu }_s$ in the early Universe, by converting ordinary neutrinos ${\nu }_{\alpha }$ in scattering processes ${\nu }_s{\nu }_{\alpha }\to {\nu }_s{\nu }_s$. After initial production by oscillations, this leads to an exponential growth in the ${\nu }_s$ abundance. We show that such a production regime naturally occurs for self-interacting ${\nu }_s$, and that this opens up significant new parameter space where ${\nu }_s$ make up all of the observed dark matter. Our results provide strong motivation to further push the sensitivity of X-ray line searches, and to improve on constraints from structure formation.

In this paper we have studied the effect of deformation and temperature on holographic entanglement entropy and mutual information between two subsystems in a deformed field theory at finite temperature. The $T\overline{T}$ deformation operator in field theory introduces a cutoff in the dual gravity background. We define different regimes of parameters and calculate the entanglement entropy and mutual information analytically. We observe that temperature and deformation parameter have similar effects on entanglement entropy and mutual information. They both lead to decrease in mutual information or somehow the correlation between the two subsystems. Interestingly we observe the emergence of correction terms in entanglement entropy and mutual information that are universal and do not depend on the scale of the nonlocal operator.

The gravastar is an exotic compact object proposed as a final product of the gravitational collapse of a massive object in order to resolve problems associated with black holes. It is enclosed by a thin crust and the inside of it is occupied by the positive cosmological constant. Recently, the present authors studied quantum particle creation through spherically symmetric gravitational collapse to form a gravastar, and showed that the newly formed gravastar emits thermal radiation with the Gibbons-Hawking temperature of its de Sitter core. In this paper, in order to understand more about the thermal radiation associated with the gravastar formation, we investigate the quantum particle creation in another toy model of the gravastar formation; a star with the hollow inside suddenly becomes a gravastar through gravitational vacuum condensation. We find that the thermal radiation is emitted from the gravastar just formed also in the present model. The thermal radiation from the gravastar just formed comes from the change of the geometry inside the star accompanied by gravitational vacuum condensate.

We demonstrate that black holes in order $N\ge 4$ Lovelock gravity can exhibit multicritical phase behavior. We show an explicit example of a quadruple point in $d=10$ fourth-order Lovelock gravity and a quintuple point in $d=14$ sixth-order Lovelock gravity. We also demonstrate that multicriticality can be realized for uncharged, nonrotating black holes by highlighting a new type of multicritical point between black holes and thermal radiation. We discuss the methodology used and make comparisons to other black hole multicritical points in terms of the Gibbs phase rule.

An only early or only late time alteration to $\mathrm{\Lambda }\mathrm{CDM}$ has been inadequate at resolving both the $H_0$ and $S_8$ tensions simultaneously; however, a combination of early and late time alterations to $\mathrm{\Lambda }\mathrm{CDM}$ can provide a solution to both tensions. As an illustration, we examine a combined early dark energy, decaying dark matter model. While early dark energy has the ability to resolve the $H_0$ tension, it leads to a discrepancy in $S_8$ measurements. We show that the addition of decaying dark matter helps resolve the $S_8$ discrepancy that would otherwise be enhanced in an early dark energy model, while the latter is able to relieve the $H_0$ disagreement to within the 95th percentile interval. Our results show a preference for the combined model over $\mathrm{\Lambda }\mathrm{CDM}$ with $\mathrm{\Delta }\mathrm{AIC}=-6.72$, hinting that both early and late Universe modifications may be necessary to address the cosmological tensions.

Galaxy surveys provide one of the best ways to constrain the theory of gravity at cosmological scales. They can be used to constrain the two gravitational potentials encoding time, $\mathrm{\Psi }$, and spatial, $\mathrm{\Phi }$, distortions, which are exactly equal at late time within general relativity. Hence, any small variation leading to a nonzero anisotropic stress, i.e., a difference between these potentials, would be an indication for modified gravity. Current analyses usually consider gravitational lensing and redshift-space distortions to constrain the anisotropic stress, but these rely on certain assumptions like the validity of the weak equivalence principle, and a specific time evolution of the functions encoding deviations from general relativity. In this work, we propose a reparametrization of the gravitational lensing observable, together with the use of the relativistic dipole of the correlation function of galaxies to directly measure the anisotropic stress with a minimum amount of assumptions. We consider the future Legacy Survey of Space and Time of the Vera C. Rubin Observatory and the future Square Kilometer Array, and show that combining gravitational lensing and gravitational redshift with the proposed approach we will achieve model-independent constraints on the anisotropic stress at the level of $\sim 20\%$.

Oscillons are localized long-lived pulsating states in the three-dimensional ${\varphi }^4$ theory. We gain insight into the spatiotemporal structure and bifurcation of the oscillons by studying time-periodic solutions in a ball of a finite radius. A sequence of weakly localized Bessel waves—nonlinear standing waves with the Bessel-like $r$-dependence—is shown to extend from eigenfunctions of the linearized operator. The lowest-frequency Bessel wave serves as a starting point of a branch of periodic solutions with exponentially localized cores and small-amplitude tails decaying slowly toward the surface of the ball. A numerical continuation of this branch gives rise to the energy-frequency diagram featuring a series of resonant spikes. We show that the standing waves associated with the resonances are born in the period-multiplication bifurcations of the Bessel waves with higher frequencies. The energy-frequency diagram for a sufficiently large ball displays sizeable intervals of stability against spherically symmetric perturbations.

We explore the discovery potential for long-lived particles at the 250-GeV ILC. The goal is to investigate possible gains of a dedicated far detector over the main detector ILD. For concreteness, we perform our study for sub-GeV axionlike particles $a$ produced via $e^{+}{e}^{-}\to a\gamma$ or $e^{+}{e}^{-}\to Z\gamma \to (a\gamma )\gamma$ and decaying into pairs of charged leptons. In the ideal case of zero background and perfect detection efficiency, we find that far detectors placed in the planned underground cavities or a large cuboid on the ground can enhance the sensitivity to long-lived pseudoscalars at best moderately. On the other hand, the ILD itself is a perfect environment to search for long-lived particles, due to its excellent angular coverage and radial thickness. For long-lived particles produced with cross sections of a few picobarns, the ILD could probe lifetimes up to 300 ns, or proper decay lengths up to 100 m, in $250{\mathrm{fb}}^{-1}$ of data. For axionlike particles produced through weak interactions, the ILC can reach an even higher sensitivity than searches for displaced vertices in meson decays at Belle II. Our findings apply similarly to other proposed electron-positron experiments with a high angular coverage, such as the FCC-ee and CEPC.

We generalize the next-to-leading order (NLO) QCD calculations for the decay rates of $h\to gg$ and $h\to \gamma \gamma$ to the case of anomalous couplings of the Higgs boson. We demonstrate how this computation can be done in a consistent way within the framework of an electroweak chiral Lagrangian, based on a systematic power counting. It turns out that no additional coupling parameters arise at NLO in QCD beyond those already present at leading order. The impact of QCD is large for $h\to gg$ and the uncertainties from QCD are significantly reduced at NLO. $h\to \gamma \gamma$ is only mildly affected by QCD; here the NLO treatment practically eliminates the uncertainties. Consequently, our results will allow for an improved determination of anomalous Higgs couplings from these processes. The relation of our framework to a treatment in Standard Model effective field theory is also discussed.

We explored the interplay between magnetic field and rotation in the de Hass–van Alphen oscillation. The effect is found to be reduced because of the reweighting of different angular momentum states within the same Landau level by rotation energy. The implications of our results on high energy physics and condensed matter physics are discussed.

We show that inclusive single-spin asymmetries (SSAs) with transversely polarized protons or electrons at a future electron ion collider (EIC) are sensitive to new physics contributions to electroweak dipole operators of electrons and quarks. We use the Standard Model Effective Field Theory (SMEFT) to parametrize possible heavy new physics contributions to these couplings. We show that new physics scales at or beyond the TeV-scale can be probed assuming realistic EIC run parameters, and that the transverse spin asymmetries are sensitive to different combinations of the dipole couplings than other measurements such as anomalous magnetic or electric dipole moments. We also study the physics potential of SSAs at a possible future upgrade of the EIC to collide muons and protons. Measurements at such an upgrade could probe the same SMEFT parameters that explain the current anomaly in the muon anomalous magnetic moment, and could also improve current bounds on the muon electric dipole moment.

We study mono-Higgs signatures emerging in an illustrative new physics scenario involving Standard Model Higgs boson decays to bottom quark pairs using hybrid deep neural networks. We use a multilayer perceptron to analyze the kinematic observables and optimize the signal-to-background discrimination. The global color flow structure of hard jets emerging from the decay of heavy particles with different color charges is crucial to single out the mono-Higgs signature. Upon embedding the different color flow structures for signal and backgrounds into constructed images, we use a convolution neural network to analyze the latter. Specifically, the approach takes initially mono-type data as input, frittering away invaluable multisource and multiscale information. We then discuss a general architecture of hybrid deep neural networks that supports instead mixed input data. In comparison with single input deep neural networks, like multilayer perceptron or convolution neural networks, the hybrid deep neural networks provide higher capacity in feature extraction and thus in signal versus background classification performance. We provide reference results for the case of the high-luminosity Large Hadron Collider.

Angular distributions of $\varphi$ meson decay amplitudes of $e^{+}{e}^{-}$ and $K^{+}{K}^{-}$ channels are computed using both specific interaction Lagrangians and simple arguments relying on angular momentum conservation. Based on the obtained results, we assess methods to experimentally disentangle the longitudinal and transverse polarization modes of the $\varphi$ meson and discuss advantages and disadvantages of employing either the leptonic or hadronic decay modes for this task.

We present the first calculation for the hadroproduction of a $W$ boson in association with a massive bottom ($b$) quark-antiquark pair at next-to-next-to-leading order (NNLO) in QCD perturbation theory. We exploit the hierarchy between the $b$-quark mass and the characteristic energy scale of the process to obtain a reliable analytic expression for the two-loop virtual amplitude with three massive legs, starting from the corresponding result available for massless $b$ quarks. The use of massive $b$ quarks avoids the ambiguities associated with the correct flavor assignment in massless calculations, paving the way to a more realistic comparison with experimental data. We present phenomenological results considering proton-proton collisions at center-of-mass energy $\sqrt{s}=13.6\mathrm{TeV}$ for inclusive $Wb\overline{b}$ production and within a fiducial region relevant for the associated production of a $W$ boson and a Higgs boson decaying into a $b\overline{b}$ pair, for which $Wb\overline{b}$ production represents one of the most relevant backgrounds. We find that the NNLO corrections are substantial and that their inclusion is mandatory to obtain reliable predictions.

The factorization theorems of QCD apply equally well to most simple quantum field theories that require renormalization but where direct calculations are much more straightforward. Working with these simpler theories is convenient for stress testing the limits of the factorization program and for examining general properties of the parton density functions or other correlation functions that might be necessary for a factorized description of a process. With this view in mind, we review the steps of factorization in a real scalar Yukawa field theory for both deep inelastic scattering and semi-inclusive deep inelastic scattering cross sections. In the case of semi-inclusive deep inelastic scattering, we illustrate how to separate the small transverse momentum region, where transverse momentum dependent parton density functions are needed, from a purely collinear large transverse momentum region, and we examine the influence of subleading power corrections. We also review the steps for formulating transverse momentum dependent factorization in transverse coordinate space, and we study the effect of transforming to the well-known $b_{*}$ scheme. Within the Yukawa theory, we investigate the consequences of switching to a generalized parton model approach and compare it with a fully factorized approach. Our results highlight the need to address similar or analogous issues in QCD.

The thermodynamics of finite size quark matter in the quasiparticle model is self-consistently constructed by an effective bag function, which presents the medium effect to the confinement. We obtained completely analytic surface tension in the strong magnetic field with the multiple reflection expansion. The anisotropic structure is demonstrated by the splitting of the longitudinal and transverse surface tensions. The anisotropy of the surface tension could be enhanced by an increase of the magnetic field. The analytical surface tension is modified by an additional term related to the bag function. For strong enough magnetic fields, the increase of the longitudinal surface tension is proportional to the magnetic field. On the contrary, the transverse component vanishes due to all quarks locating in the lowest Landau level.