Many proposals for physics beyond the Standard Model give rise to a dark sector containing many degrees of freedom. In this work, we explore the cosmological implications of the nontrivial dynamics which may arise within such dark sectors, focusing on decay processes which take place entirely among the dark constituents. First, we demonstrate that such decays can leave dramatic imprints on the resulting dark-matter phase-space distribution. In particular, this distribution need not be thermal—it can even be multimodal, exhibiting a nontrivial pattern of peaks and troughs as a function of momentum. We then proceed to show how these features can induce modifications to the matter power spectrum. Finally, we assess the extent to which one can approach the archaeological “inverse” problem of deciphering the properties of an underlying dark sector from the matter power spectrum. Indeed, one of the main results of this paper is a remarkably simple conjectured analytic expression which permits the reconstruction of many of the important features of the dark-matter phase-space distribution directly from the matter power spectrum. Our results therefore provide an interesting toolbox of methods for learning about, and potentially constraining, the features of nonminimal dark sectors and their dynamics in the early universe.

In this paper, we explore the possibility of the polarization conversion of a wide energy range of cosmic photons to the circular polarization through their interactions with right handed sterile neutrinos as a candidate for dark matter. By considering the sterile neutrino in the seesaw mechanism framework and right-handed current model, we examine the Faraday conversion $\mathrm{\Delta }{\varphi }_{\mathrm{FC}}$ of gamma ray burst (GRB) photons at both the prompt and afterglow emission levels as well as the radio photons emitted from our galaxy and extra-galactic sources interacting with the sterile neutrinos. Consequently, for the sterile neutrino with mixing angle ${\theta }^2\lesssim {10}^{-2}$ motivated by models with a hidden sector coupled to the sterile neutrino, the Faraday conversion can be estimated as $\mathrm{\Delta }{\varphi }_{\mathrm{FC}}\lesssim {10}^{-3}–{10}^{-18}\mathrm{rad}$ for GRB, $\mathrm{\Delta }{\varphi }_{\mathrm{FC}}\lesssim {10}^{-6}–{10}^{-11}\mathrm{rad}$ for radio emission source from our galaxy and $\mathrm{\Delta }{\varphi }_{\mathrm{FC}}\lesssim {10}^{-6}–{10}^{-15}\mathrm{rad}$ for extragalactic sources. We also examine the V-mode power spectrum $C_{Vl}$ of the cosmic microwave background (CMB) at the last scattering surface. We show that the circular polarization power spectrum at the leading order is proportional to the linear polarization power spectrum $C_{pl}$ and the mixing angle where for ${\theta }^2\lesssim {10}^{-2}$ leads to $C_{Vl}\lesssim 0.01$ nano-Kelvin squared.

We formulate a theory of dissipative hydrodynamics with spontaneously broken translations, describing charge density waves in a clean isotropic electronic crystal. We identify a novel linear transport coefficient, lattice pressure, capturing the effects of background strain and thermal expansion in a crystal. We argue that lattice pressure is a generic feature of systems with spontaneously broken translations and must be accounted for while building and interpreting holographic models. We also provide the first calculation of the coefficients of thermal and chemical expansion in a holographic electronic crystal.

By adding the dimension-six operator for the Higgs potential (denoted ${\mathcal{O}}_6$) in Standard Model, we have a first-order electroweak phase transition (EWPT) whose strength is larger than unity. The cutoff parameter of the dimension-six Higgs operator ($\mathrm{\Lambda }$) is found to be in the range 593–860 GeV with the Wilson parameter equal to unity; it is also shown that the greater the $\mathrm{\Lambda }$, the lower the phase transition strength and the larger the Wilson parameter, the wider the domain of $\mathrm{\Lambda }$. At zero temperature, the sphaleron energy is calculated with a smooth Ansatz and an Ansatz with scale-free parameters, thereby we find that smooth profiles are not more accurate than profiles with scale-free parameters. Then, using the one-loop effective Higgs potential with the inclusion of ${\mathcal{O}}_6$ instead of all possible dimension-six operators, we directly calculate the electroweak sphaleron energy at finite temperature with the scale-free parameters Ansatz and show that the decoupling condition is satisfied during the phase transition. Moreover, we can reevaluate the upper bound of the cutoff scale inferred from the first-order phase transition. In addition, with the upper bound of the cutoff parameter (about 800–860 GeV), EWPT is a solution to the energy scale of the dimension-six operators. There is an extended conclusion that EWPT can only be solved at a large energy scale than that of SM.

In our previous work [M. D. Ćirić et al., Classical Quantum Gravity 35, 175005 (2018)] we constructed a model of a noncommutative, charged, and massive scalar field based on the angular twist. Then we used this model to analyze the motion of the scalar field in the Reissner-Nordström black hole background. In particular, we determined the quasinormal mode (QNM) spectrum analytically in the near-extremal limit. To broaden our analysis, in this paper we apply a well-defined numerical method, the continued fraction method, and calculate the QNM spectrum for a nonextremal Reissner-Nordström black hole. To check the validity of our analytic calculations, we compare results of the continued fraction method in the near extremal limit with the analytic results obtained in the previous paper. We find that the results are in good agreement. For completeness, we also study the QNM spectrum in the Wentzel-Kramers-Brillouin approximation.

The three-loop QED mass-dependent contributions to the $g-2$ of each of the charged leptons with two internal closed fermion loops, sometimes called $A_3^{(6)}(\frac{m_1}{m_2},\frac{m_1}{m_3})$ in the $g-2$ literature, is revisited using the Mellin-Barnes (MB) representation technique. Results for the muon and $\tau$ lepton anomalous magnetic moments $A_{3,\mu }^{(6)}$ and $A_{3,\tau }^{(6)}$, which were known as series expansions in the lepton mass ratios up to the first few terms only, are extended to their exact expressions. The contribution to the anomalous magnetic moment of the electron $A_{3,e}^{(6)}$ is also explicitly given in closed form. In addition to this, we show that the different series representations derived from the MB representation collectively converge for all possible values of the masses. Such unexpected behavior is related to the fact that these series bring into play double hypergeometric series that belong to a class of Kampé de Fériet series which we prove to have the same simple convergence and analytic continuation properties as the Appell $F_1$ double hypergeometric series.

We study direct detection bounds on cosmic ray-upscattered dark matter in simplified models including light mediators. We find that the energy dependence in the scattering cross section is significant, and produces stronger bounds than previously found (which assumed constant cross sections) by many orders of magnitude at low dark matter mass. Finally, we compute the “neutrino-floor” that will limit future direct detection searches for cosmic ray-upscattered dark matter. While we focus on vector interactions for illustration, we emphasize that the energy dependence is critical in determining accurate bounds on any particle physics model of dark matter-cosmic ray interactions from experimental data on this scenario.

In order to address this question, we consider a simple renormalizable and gauge invariant model in which the $Z^{\prime }$ only has couplings to the electron and muon and their associated neutrinos, arising from mixing with a heavy vectorlike fourth family of leptons. Within this model we discuss the contributions to the electron and muon anomalous magnetic moments from $Z^{\prime }$ exchange, subject to the constraints from $\mu \to e\gamma$ and neutrino trident production. Using analytic and numerical arguments, we find that such a $Z^{\prime }$ model can account for either the electron or the muon $g-2$ anomalies, but not both, while remaining consistent with the experimental constraints from $\mu \to e\gamma$ and neutrino trident production.

At the LHC, a TeV-scale leptoquark (LQ) that decays dominantly to a top quark ($t$) and a light charged lepton ($\ell =e$, $\mu$) would form a resonance system of boosted-$t+$ high-$p_{\mathrm{T}}\text{−}\ell$. We consider all possible vector LQ models within the Buchmüller-Rückl-Wyler classifications with the desired decay. We propose simple phenomenological Lagrangians that are suitable for bottom-up/experimental studies and, at the same time, can cover the relevant parameter spaces of these models. In this simplified framework, we study the pair and single production channels of vector LQs at the LHC. Interestingly, we find that, like the pair production, the cross sections of some single production processes also depend on the parameter $\kappa$ that appears in the gluon-vector LQ coupling. We adopt a search strategy of selecting events with at least one boosted hadronic top quark and exactly two high-$p_{\mathrm{T}}$ leptons of the same flavor and opposite sign. This combines events from the pair and single production processes and, therefore, can enhance the discovery potential beyond that of the pair-production-only searches. For $5\sigma$ discovery we find that vector LQs can be probed up to 2.55 TeV for 100% branching ratio in the $t\ell$ decay mode and $\mathcal{O}(1)$ new couplings at the 14 TeV LHC with $3{\mathrm{ab}}^{-1}$ of integrated luminosity.

Lattice QCD calculations of nucleon form factors are restricted to discrete values of the Euclidean four-momentum transfer. Therefore, the extraction of radii typically relies on parametrizing and fitting the lattice QCD data to obtain its slope close to zero momentum transfer. We investigate a new method, which allows to compute the nucleon radius directly from existing lattice QCD data, without assuming a functional form for the momentum dependence of the underlying form factor. The method is illustrated for the case of the isovector mean-square charge radius of the nucleon $⟨r_{\mathrm{isov}}^2⟩$ and the quark-connected contributions to $⟨r_p^2⟩$ and $⟨r_n^2⟩$ for the proton and neutron, respectively. Computations are performed using a single gauge ensemble with $N_f=2+1+1$ maximally twisted mass clover-improved fermions at physical quark mass and a lattice spacing of $a=0.08\mathrm{fm}$.

We present the first calculation of the hadronic tensor on the lattice for the nucleon. The hadronic tensor can be used to extract structure functions in deep inelastic scatterings and to provide information for neutrino-nucleon scattering which is crucial to neutrino-nucleus scattering experiments at low energies. The most challenging part in the calculation is to solve an inverse problem. We have implemented and tested three algorithms using mock data, showing that the Bayesian reconstruction method has the best resolution in extracting peak structures while the Backus-Gilbert and maximum entropy methods are somewhat more stable for smooth functions. Numerical results are presented for both the elastic case (clover fermions on domain wall configurations with $m_{\pi }\sim 370\mathrm{MeV}$ and $a\sim 0.06\mathrm{fm}$) and a case (anisotropic clover lattice with $m_{\pi }\sim 380\mathrm{MeV}$ and $a_t\sim 0.035\mathrm{fm}$) with large momentum transfer. For the former case, the reconstructed Minkowski hadronic tensor gives precisely the vector charge which proves the feasibility of the approach. For the latter case, the resonance and possibly shallow inelastic scattering contributions around energy transfer $\nu =1\mathrm{GeV}$ are clearly observed but no information is obtained for higher excited states with $\nu >2\mathrm{GeV}$. A check of the effective masses of the $\rho$ meson with different lattice setups indicates that, in order to reach higher energy transfers, using lattices with smaller lattice spacings is essential.

We study string fragmentation in high multiplicity proton-proton collisions in a model where the string tension fluctuates. These fluctuations produce exponential pion spectra which are fitted to the transverse momentum distributions of charged particles for different multiplicities. For each multiplicity the so obtained hadronic slope parameter defines the magnitude of the string fluctuations which in turn determines the produced ratio of strange to light quarks. pythia string decay simulations are used to convert each ratio of strange to light quarks to the appropriate ratio of strange hadrons to pions.

Correlation functions of Yang-Mills theory in the Landau gauge are calculated from their equations of motion. The employed setup is completely parameter free and leads, within errors, to good quantitative agreement with corresponding lattice results for the ghost and gluon propagators as well as the ghost-gluon and three-gluon vertices. Also, the four-gluon vertex is calculated. The present setup allows for the first time for a unique subtraction of quadratic divergences in the gluon propagator Dyson-Schwinger equation. Thus, there are no ambiguities which can arise due to the use of models or auxiliary workarounds. In addition, several self-tests of the results are described that allow assessing the truncation error in a self-consistent way. This enables a new perspective on how to identify limitations of the present setup and develop future improvements.

We present a search for seven lepton-flavor-violating neutral charm meson decays of the type $D^0\to X^0{e}^{\pm }{\mu }^{\mp }$, where $X^0$ represents a ${\pi }^0$, $K_{\mathit{S}}^0$, ${\overline{K}}^{*0}$, ${\rho }^0$, $\varphi$, $\omega$, or $\eta$ meson. The analysis is based on $468{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected at or close to the $\mathrm{\Upsilon }(4S)$ resonance with the BABAR detector at the SLAC National Accelerator Laboratory. No significant signals are observed, and we establish 90% confidence level upper limits on the branching fractions in the range $(5.0-22.5)\times {10}^{-7}$. The limits are between 1 and 2 orders of magnitude more stringent than previous measurements.

Crucial inputs for a variety of $CP$-violation studies can be determined through the analysis of pairs of quantum-entangled neutral $D$ mesons, which are produced in the decay of the $\psi (3770)$ resonance. The relative strong-phase parameters between $D^0$ and ${\overline{D}}^0$ in the decays $D^0\to K_{S,L}^0{\pi }^{+}{\pi }^{-}$ are studied using $2.93{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data delivered by the BEPCII collider and collected by the BESIII detector at a center-of-mass energy of 3.773 GeV. Results are presented in regions of the phase space of the decay. These are the most precise measurements to date of the strong-phase parameters in $D\to K_{S,L}^0{\pi }^{+}{\pi }^{-}$ decays. Using these parameters, the associated uncertainty on the Cabibbo-Kobayashi-Maskawa angle $\gamma /{\varphi }_3$ is expected to be between 0.7° and 1.2° for an analysis using the decay $B^{\pm }\to D{K}^{\pm }$, $D\to K_S^0{\pi }^{+}{\pi }^{-}$, where $D$ represents a superposition of $D^0$ and ${\overline{D}}^0$ states. This is a factor of 3 smaller than that achievable with previous measurements. Furthermore, these results provide valuable input for charm-mixing studies, other measurements of $CP$ violation, and the measurement of strong-phase parameters for other $D$-decay modes.

We analyze the precise data obtained by the CMD-3 experiment on the $e^{+}{e}^{-}$ annihilation into two charged kaons in the vicinity of the $\varphi$ peak. A perfect fit is obtained only if a pole on the real axis below the reaction threshold is assumed. This can be interpreted as proof of the existence of the 2p state of kaonium, a compound of $K^{+}$ and $K^{-}$. The BABAR Collaboration data on the same process supports this conclusion and, in addition, points to the strong interaction as a dominant source of the binding energy. The possibility of discovering 2p kaonium in the $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}$ process is discussed. The 2p state of $K^0$-onium is indicated on the basis of the CMD-3 $e^{+}{e}^{-}\to K_S^0{K}_L^0$ data.

We try to introduce heavy flavors to Sakai-Sugimoto model by regarding higher dimensional components of gauge fields as heavy mesons. Using the Forgács and Manton approach, we obtain a theory composed of heavy mesons and the instanton of light flavors. Applying the collective coordinate quantization method, we derived a mass formula of heavy baryons. In the leading order of $1/m_H$ expansion ($m_H$ the mass of a heavy quark), we find singlet and doublet states in the heavy quark symmetry (HQS). Also, we obtain the degenerate Roper like and odd parity excitations. By virtue of heavy meson degrees of freedom, our mass formula reproduces the mass ordering of ${\mathrm{\Sigma }}_c^{*}$ and ${\mathrm{\Lambda }}_c^{*}$ correctly.

In this work, we study the circuit complexity for generalized coherent states in thermal systems by adopting the covariance matrix approach. We focus on the coherent thermal (CT) state, which is non-Gaussian and has a nonvanishing one-point function. We find that even though the CT state cannot be fully determined by the symmetric two-point function, the circuit complexity can still be computed in the framework of the covariance matrix formalism by properly enlarging the covariance matrix. Now the group generated by the unitary is the semiproduct of translation and the symplectic group. If the reference state is Gaussian, the optimal geodesic is still be generated by a horizontal generator such that the circuit complexity can be read from the generalized covariance matrix associated to the target state by taking the cost function to be $F_2$. For a single harmonic oscillator, we discuss carefully the complexity and its formation in the cases that the reference states are Gaussian and the target space is excited by a single mode or double modes. We show that the study can be extended to the free scalar field theory.

To understand the time-dependent quantum correlation in expanding universes, we study the time-dependent entanglement entropy in the braneworld model. If we take into account a generalized string cloud geometry caused by uniformly distributed open strings, cosmologies on the braneworld result in the standard Friedmann-Lemaître-Robertson-Walker cosmologies with various matter contents. On the dual field theory side, open strings are reinterpreted as fundamental matter, while the black hole mass corresponds to the excitation energy of massless gauge bosons. We show how the string cloud geometry is matched to various braneworld cosmologies, for example, eternal inflation and radiation- and matter-dominated universes. Then we investigate how the entanglement entropy evolves in those expanding universes.

We construct analytic ($3+1$)-dimensional Skyrmions living at finite baryon density in the $SU(N)$ Skyrme model that are not trivial embeddings of $SU(2)$ into $SU(N)$. We use Euler angle decomposition for arbitrary $N$ and the generalized hedgehog ansatz at finite baryon density. The skyrmions of high topological charge that we find represent smooth baryonic layers whose properties can be computed explicitly. In particular, we determine the energy-to-baryon charge ratio for any $N$ showing the smoothness of the large-$N$ limit. The closeness to the BPS bound of these configurations can also be analyzed. The energy density profiles of these finite density skyrmions have a “lasagna-like” shape, in agreement with recent experimental findings. The shear modulus can be precisely estimated as well, and our analytical result is close to recent numerical studies in the literature.