Anisotropic diffusion is one of the potential interpretations for the morphology of the Geminga pulsar halo. It interprets the observed slow-diffusion phenomenon through a geometric effect, assuming the mean magnetic field direction around Geminga is closely aligned with the line of sight toward it. However, this direction should not extend further than the correlation length of the turbulent magnetic field $L_c$, which could be 100 pc or less. We first revisit the $L_c=\infty$ scenario and show that the halo asymmetry predicted by this scenario is mainly contributed by the electrons located beyond the “core” section around Geminga, which has a length of 100 pc. Then, considering the directional variation of the magnetic field beyond the core section, we take one magnetic field configuration as an example to investigate the possible halo morphology. The predicted morphology has some different features compared to the $L_c=\infty$ scenario. The current experiments may already be able to test these features. In addition, we use a semi-analytical method to solve the anisotropic propagation equation, which offers significant convenience compared to numerical approaches.

Photon–axion-like particle (ALP) oscillations result in the survival of gamma rays from distant sources above TeV energies. Studies of events observed by CAST, Fermi-LAT, and IACT have constrained the ALP parameters. We investigate the effect of photon-ALP oscillations on the gamma-ray spectra of the first extragalactic neutrino source, TXS $0506+056$, for observations by Fermi-LAT and MAGIC around the IC170922-A alert. We obtain a constraint on the ALP coupling parameter $g_{a\gamma }<5\times {10}^{-11}{\mathrm{GeV}}^{-1}$ with 95% C.L. when focusing on the ALP mass range $0.1\mathrm{neV}\le m_a\le 1000\mathrm{neV}$. Importantly, we study the implications of $\mathrm{ALP}\text{−}\gamma$ oscillations on the counterpart $\gamma$ rays of the sub-PeV neutrinos observed from TXS $0506+056$. We also show the diffuse $\gamma$-ray fluxes and observabilities from flat-spectrum radio quasars, high-synchrotron peaked sources, and low-intermediate-synchrotron peaked sources, assuming similar gamma-ray emissions as that from TXS $0506+056$.

Within the bottom-up approach to holography, we construct a class of six-dimensional gravity models and discuss solutions that can be interpreted, asymptotically in the far UV, in terms of dual five-dimensional conformal field theories deformed by a single scalar operator. We treat the scaling dimension of this operator, related to the mass of the one scalar field in the gravity theory, as a free parameter. One dimension in the regular geometry is compactified on a shrinking circle, hence mimicking confinement in the resulting dual four-dimensional theories. We study the mass spectrum of bosonic states. The lightest state in this spectrum is a scalar particle. Along the regular (confining) branch of solutions, we find the presence of a tachyonic instability in part of the parameter space, reached by a smooth deformation of the mass spectrum, as a function of the boundary value of the background scalar field in the gravity theory. In a region of parameter space nearby the tachyonic one, the lightest scalar particle can be interpreted as an approximate dilaton, sourced by the trace of the stress-energy tensor, and its mass is parametrically suppressed. We also compute the free energy, along several branches of gravity solutions. We find that both the dilatonic and tachyonic regions of parameter space, identified along the branch of confining solutions, are hidden behind a first-order phase transition, so that they are not realized as stable solutions, irrespectively of the scaling dimension of the deforming field-theory operator. The (approximate) dilaton, in particular, appears in metastable solutions. Yet, the mass of the lightest state, computed close to the phase transition, is (mildly) suppressed. This feature is amplified when the (free) parameter controlling the scaling dimension of the deformation is $5/2$, half the dimension of space-time in the field theory.

There has been great interest in a model with three-Higgs-doublets in which fermions with a particular charge couple to a single and distinct Higgs field. We study the phenomenological differences between the two common incarnations of this so-called type-Z three-Higgs-doublet model (3HDM). We point out that the differences between the two models arise from the scalar potential only. Thus we focus on observables that involve the scalar self-couplings. We find it difficult to uncover features that can uniquely set apart the $Z_3$ variant of the model. However, by studying the dependence of the trilinear Higgs couplings on the nonstandard masses, we have been able to isolate some of the exclusive indicators for the $Z_2\times Z_2$ version of the type-Z 3HDM. This highlights the importance of precision measurements of the trilinear Higgs couplings.

We update results on the QCD equation of state in ($2+1$)-flavor QCD with nonzero conserved charge chemical potentials obtained from an eighth-order Taylor series. To construct bulk thermodynamic observables, we use continuum extrapolated results for the second and fourth order expansion coefficients of pressure, while using spline interpolated result based on high statistics $N_{\tau }=8$ data for the sixth and eighth order expansion coefficients. We present results for basic bulk thermodynamic observables of strangeness-neutral strong-interaction matter, i.e., pressure, number densities, energy, and entropy density, and resum Taylor series results using Padé approximants. Furthermore, we calculate the speed of sound as well as the adiabatic compression factor of the strangeness-neutral matter on lines of constant entropy per net baryon number. We show that the equation of state [$P(n_B),\epsilon (n_B)$] is already well described by the 4th-order Taylor series in almost the entire range of temperatures accessible with the beam energy scan in collider mode at the Relativistic Heavy Ion Collider.

Hadronic matrix elements evaluated on the lattice can be converted to a continuum scheme such as $\overline{\mathrm{MS}}$ using intermediate nonperturbative renormalization schemes. Discretization effects on the lattice and convergence of the continuum perturbation theory are both scheme dependent and we explore this dependence in the framework of the Rome-Southampton method for generalized kinematics. In particular, we implement several nonexceptional interpolating momentum schemes, where the momentum transfer is not restricted to the symmetric point defined in $\mathrm{RI}/\mathrm{SMOM}$. Using flavor nonsinglet quark bilinears, we compute the renormalization factors of the quark mass and wave function for $N_f=3$ flavors of dynamical quarks. We investigate the perturbative and nonperturbative scale dependencies. Our numerical results are obtained from lattice simulations performed with domain-wall fermions, based on ensembles generated by RBC-UKQCD collaborations; we use two different lattice spacings $1/a\sim 1.79$ and 2.38 GeV. We also give the numerical values for the relevant anomalous dimensions and matching coefficients at next-to-next-to-leading order.

We present the first physical-continuum limit $x$-dependent nucleon gluon distribution from lattice QCD using the pseudo-PDF approach, on lattice ensembles with $2+1+1$ flavors of highly improved staggered quarks (HISQ), generated by MILC Collaboration. We use clover fermions for the valence action on three lattice spacings $a\approx 0.9$, 0.12 and 0.15 fm and three pion masses $M_{\pi }\approx 220$, 310 and 690 MeV, with nucleon two-point measurements numbering up to $O({10}^6)$ and nucleon boost momenta up to 3 GeV. We study the lattice-spacing and pion-mass dependence of the reduced pseudo–Ioffe-time distribution matrix elements obtained from the lattice calculation, then extrapolate them to the continuum-physical limit before extracting $xg(x)/⟨x{⟩}_g$. We use the gluon momentum fraction $⟨x{⟩}_g$ calculated from the same ensembles to determine the nucleon gluon unpolarized PDF $xg(x)$ for the first time entirely through lattice-QCD simulation. We compare our results with previous single-ensemble lattice calculations, as well as selected global fits.

An earlier developed $k_T$-factorization framework to calculate the associated prompt photon and hadronic jets production cross sections at high energies is extended now to the electron-proton deep inelastic scattering. The proposed method is based on joint usage of the pegasus and cascade Monte-Carlo event generators, which deal with the transverse momentum dependent (TMD) gluon and quark densities in a proton. The first of them, pegasus, is applied to produce off-shell photon-gluon fusion events. Then, to properly simulate the kinematics of the produced jets, the TMD parton shower algorithm implemented into the cascade is used. We demonstrate basic features of the approach considering latest H1 and ZEUS data on prompt photon plus jet production at low $Q^2$ collected at HERA. We achieve a good description of the measurements and point out that a correct simulation of parton showers is essential for studying noninclusive processes at high energies within the TMD-based approaches.

Within the framework of nonrelativistic QCD (NRQCD) factorization formalism, we compute QCD next-to-next-to-leading order (NNLO) corrections to the helicity amplitudes as well as the decay width of $Z\to H+\gamma$, where $H$ can be ${\eta }_Q(Q=c,b),J/\psi$, or $\mathrm{\Upsilon }$. In addition, we resum the next-to-leading logarithms (NLL) of $m_Z^2/m_Q^2$ to all orders of ${\alpha }_s$ for the leading-twist helicity amplitude by employing the light-cone factorization approach. It is worth mentioning that we obtain the analytic expressions of the truncated NLL at ${\alpha }_s^2$. We find that the $\mathcal{O}({\alpha }_s)$ corrections are around 10% for ${\eta }_c$ and $\mathrm{\Upsilon }$ productions, however insignificant for $J/\psi$ and ${\eta }_b$ productions. The $\mathcal{O}({\alpha }_s^2)$ corrections are moderate for charmonium production, while very small for bottomonium production. Moreover, it is found that the NLL resummation can considerably alter the NRQCD prediction, especially for $J/\psi$ production. Combining the NRQCD and light-cone computation, we make phenomenological predictions on the decay widths and branching fractions. In addition, we investigate the dependence of the theoretical results on the heavy quark mass, and find the branching fraction of $Z\to H+\gamma$ monotonically decreases as $m_Q$ increases.

We predict femtoscopy correlation functions for $S$-wave $D_{(s)}\varphi$ pairs of lightest pseudoscalar open-charm mesons and Goldstone bosons from next-to-leading-order unitarized heavy-meson chiral perturbation theory amplitudes. The effect of the two-state structure around 2300 MeV can be clearly seen in the $(S,I)=(0,1/2)$ $D\pi$, $D\eta$, and $D_s\overline{K}$ correlation functions, while in the scalar-strange (1,0) sector, the $D_{s0}^{*}(2317{)}^{\pm }$ state lying below the $DK$ threshold produces a depletion of the correlation function near threshold. These exotic states owe their existence to the nonperturbative dynamics of Goldstone-boson scattering off $D_{(s)}$. The predicted correlation functions could be experimentally measured and will shed light into the hadron spectrum, confirming that it should be viewed as more than a collection of quark model states.

Axionlike particles (ALPs) belong to a well motivated class of particles which are part of a more complete UV theory. In this work, we initiate and present the inclusion of such ALPs or the conventional axions in the heavy hadron chiral perturbation theory in a model independent effective Lagrangian way. Such a framework is well suited for studying heavy to heavy quark flavor preserving transitions. For light ALPs, the limits on the ALP couplings (or their combinations) turn out to be independent of ALP mass. Radiative and leptonic decays of heavy vector mesons to corresponding heavy pseudoscalar mesons will be able to provide some of the most stringent constraints on ALPs, particularly the diagonal couplings.

A search is presented for displaced production of Higgs bosons or $Z$ bosons, originating from the decay of a neutral long-lived particle (LLP) and reconstructed in the decay modes $H\to \gamma \gamma$ and $Z\to ee$. The analysis uses the full Run 2 dataset of proton-proton collisions delivered by the LHC at an energy of $\sqrt{s}=13\mathrm{TeV}$ between 2015 and 2018 and recorded by the ATLAS detector, corresponding to an integrated luminosity of $139{\mathrm{fb}}^{-1}$. Exploiting the capabilities of the ATLAS liquid argon calorimeter to precisely measure the arrival times and trajectories of electromagnetic objects, the analysis searches for the signature of pairs of photons or electrons which arise from a common displaced vertex and which arrive after some delay at the calorimeter. The results are interpreted in a gauge-mediated supersymmetry breaking model with pair-produced Higgsinos that decay to LLPs, and each LLP subsequently decays into either a Higgs boson or a $Z$ boson. The final state includes at least two particles that escape direct detection, giving rise to missing transverse momentum. No significant excess is observed above the background expectation. The results are used to set upper limits on the cross section for Higgsino pair production, up to a ${\tilde{\chi }}_1^0$ mass of 369 (704) GeV for decays with 100% branching ratio of ${\tilde{\chi }}_1^0$ to Higgs ($Z$) bosons for a ${\tilde{\chi }}_1^0$ lifetime of 2 ns. A model-independent limit is also set on the production of pairs of photons or electrons with a significant delay in arrival at the calorimeter.

A search for the direct production of a pair of $\tau$ sleptons, the supersymmetric partners of $\tau$ leptons, is presented. Each $\tau$ slepton is assumed to decay to a $\tau$ lepton and the lightest supersymmetric particle (LSP), which is assumed to be stable and to not interact in the detector, leading to an imbalance in the total reconstructed transverse momentum. The search is carried out in events identified as containing two $\tau$ leptons, each decaying to one or more hadrons and a neutrino, and significant transverse momentum imbalance. In addition to scenarios in which the $\tau$ sleptons decay promptly, the search also addresses scenarios in which the $\tau$ sleptons have sufficiently long lifetimes to give rise to nonprompt $\tau$ leptons. The data were collected in proton-proton collisions at a center-of-mass energy of $13\mathrm{TeV}$ at the CERN LHC with the CMS detector in 2016–2018, and correspond to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. No significant excess is seen with respect to standard model expectations. Upper limits on cross sections for the pair production of $\tau$ sleptons are obtained in the framework of simplified models. In a scenario in which the $\tau$ sleptons are superpartners of left-handed $\tau$ leptons, and each undergoes a prompt decay to a $\tau$ lepton and a nearly massless LSP, $\tau$ slepton masses between 115 and 340 GeV are excluded. In a scenario in which the lifetime of the $\tau$ sleptons corresponds to $c{\tau }_0=0.1\mathrm{mm}$, where ${\tau }_0$ represents the mean proper lifetime of the $\tau$ slepton, masses between 150 and 220 GeV are excluded.

In this paper, we study the holographic quantum error correcting code properties in different boundary fractal-like structures. We construct and explore different examples of the uberholographic bulk reconstruction corresponding to these structures in higher dimensions for Cantor-like sets, thermal states, and $T\overline{T}$-deformed conformal field theories. We show how the growth of the dimensionality of the system emphasizes the role of the Cantor set, due to the special bound naturally arising in this context.

A modular representation for the semileptonic decays of baryons originating from spin-polarized and correlated baryon-antibaryon pairs is derived. The complete spin information of the decaying baryon is propagated to the daughter baryon via a real-valued matrix. It allows us to obtain joint differential distributions in sequential processes involving the semileptonic decay in a straightforward way. The formalism is suitable for extraction of the semileptonic form factors in experiments where strange baryon-antibaryon pairs are produced in electron-positron annihilation or in charmonia decays. We give examples such as the complete angular distributions in the $e^{+}{e}^{-}\to \mathrm{\Lambda }\overline{\mathrm{\Lambda }}$ process, where $\mathrm{\Lambda }\to p{e}^{-}{\overline{\nu }}_e$ and $\overline{\mathrm{\Lambda }}\to \overline{p}{\pi }^{+}$. The formalism can also be used to describe the distributions in semileptonic decays of charm and bottom baryons. Using the same principles, the modules to describe electromagnetic and neutral current weak baryon decay processes involving a charged lepton-antilepton pair can be obtained. As an example, we provide the decay matrix for the Dalitz transition between two spin-$1/2$ baryons.

At the HL-LHC and future high energy colliders, a sample of a billion top quarks will be produced, allowing precision searches for new physics in top quark decay and production. To aid in this endeavor, we characterize the independent three and four point on-shell amplitudes involving top quarks, under the assumption of $SU(3{)}_c\times U(1{)}_{em}$ invariance. The four point amplitudes factorize into primary and descendent amplitudes, where descendants are primaries multiplied by Mandelstam variables. By enumerating the allowed amplitudes, we can check for amplitude redundancies to find the number of independent terms and convert those into a Lagrangian which parametrizes these amplitudes. These results are then cross checked by utilizing the Hilbert series to count the number of independent Lagrangian operators. Interestingly, we find situations where the Hilbert series has cancellations which, if naïvely interpreted, would lead to the incorrect conclusion that there are no primary operators at a given mass dimension. We characterize the four fermion ($ffff$) and two fermion, two gauge boson ($ffVV$) operators respectively up to dimension 12 and 13. Finally, by combining unitarity bounds on the coupling strengths and simple estimates of the branching ratio sensitivities, we highlight interesting amplitudes for top quark decay that should be studied more closely at the HL-LHC. Of those highlighted, there are both new charge current and flavor changing neutral current decays that occur at dimension 8 and 10 in SMEFT.

We study the conformally reduced $R+R^2$ theory of gravity and we show that the theory is asymptotically safe with an ultraviolet critical manifold of dimension three. In particular, we discuss the universality properties of the fixed point and its stability under the use of different regulators with the help of the proper-time flow equation. We find three relevant directions, corresponding to the $\sqrt{g}$, $\sqrt{g}R$, and $\sqrt{g}{R}^2$ operators, whose critical properties are very similar to the ones shared by the full theory. Our result shows that the basic mechanism at the core of the asymptotic safety program is still well described by the conformal sector also beyond the Einstein-Hilbert truncation. Possible consequences for the asymptotic safety program are discussed.

Do gravitational interactions respect the basic principles of relativity and quantum mechanics? We show that any graviton $S$-matrix that satisfies these assumptions cannot significantly differ from General Relativity at low energies. We provide sharp bounds on the size of potential corrections in terms of the mass $M$ of new higher-spin states, in spacetime dimensions $D\ge 5$ where the $S$-matrix does not suffer from infrared ambiguities. The key novel ingredient is the full set of $\mathrm{SO}(D-1)$ partial waves for this process, which we show how to efficiently compute with Young tableau manipulations. We record new bounds on the central charges of holographic conformal theories.