We study corrections to observables related to the muon in the context of models of new physics which generate mass-enhanced corrections to the muon dipole moments. Working in the Standard Model effective theory, we demonstrate a correlation between the decay of the Higgs boson to muons and the magnetic and electric dipole moments of the muon generated by the dominant matching corrections. This defines a novel way to classify predictions for a wide variety of models of new physics based on the pattern of deviations of these three observables. In particular, when applied to specific models, we find that this correlation has a potential to rule out whole models or set upper bounds on the scale of new physics motivated by the muon anomalous magnetic moment.

In this work, we propose and explore for the first time a new collider signature of heavy neutral scalars typically found in many distinct classes of multi-Higgs models. This signature, particularly relevant in the context of the Large Hadron Collider (LHC) measurements, is based on a topology with two charged leptons and four jets arising from first and second generation quarks. As an important benchmark scenario of the multi-Higgs models, we focus on a recently proposed Branco-Grimus-Lavoura (BGL) type model enhanced with an Abelian U(1) flavor symmetry and featuring an additional sector of right-handed neutrinos. We discuss how kinematics of the scalar fields in this model can be used to efficiently separate the signal from the dominant backgrounds and explore the discovery potential of the new heavy scalars in the forthcoming LHC runs. The proposed method can be applied for analysis of the statistical significance of heavy scalars’ production at the LHC and future colliders in any multi-Higgs model.

We construct the general partial wave amplitude basis for the $N\to M$ scattering, which consists of Poincaré Clebsch-Gordan coefficients, in a Lorentz invariant form given in terms of the spinor-helicity variables. The inner product of the Clebsch-Gordan coefficients is defined, which converts on-shell phase space integration into an algebraic problem. We also develop the technique of partial wave expansions of arbitrary amplitudes, including those with infrared divergence. These are applied to the computation of anomalous dimension matrix for general effective operators, where unitarity cuts for the loop amplitudes, with an arbitrary number of external particles, are obtained via partial wave expansion.

We study the generation number of massless fermions in compactifications recently found in heterotic supergravity. The internal spaces are products of two-dimensional spaces of constant curvature, and the standard embedding is not assumed. The generation number is constrained by the equations of motion and the Bianchi identity. In the case that the Euler characteristics of the three internal submanifolds are $(2,-2,-2)$, the generation number is three or less. We also show that three-generation solutions exist for arbitrary Euler characteristics of the negatively curved 2-manifolds, and we present some explicit solutions.

In this paper we study $I=0$ bottomonium in $S$, $P$, $D$ and $F$ waves considering five coupled channels, one confined quarkonium and four open $B^{(*)}{\overline{B}}^{(*)}$ and $B_s^{(*)}{\overline{B}}_s^{(*)}$ meson-meson channels. To this end we use and extend a recently developed novel approach utilizing lattice QCD string breaking potentials for the study of quarkonium bound states and resonances. This approach is based on the Born-Oppenheimer approximation and the unitary emergent wave method and allows to compute the poles of the $\mathrm{T}$ matrix. We compare our results to existing experimental results for $I=0$ bottomonium and discuss masses, decay widths and the assignment of angular momentum quantum numbers. Moreover, we determine the quarkonium and meson-meson composition of these states to clarify, which of them are ordinary quarkonium, and which of them should rather be interpreted as tetraquarks.

We study the process $D^0\to {\pi }^{+}{\pi }^{-}{f}_0(980)$, $f_0\to {\pi }^{+}{\pi }^{-}$ by introducing the triangle mechanism, in which $f_0(980)$ is considered to be dynamically generated from the meson-meson interaction. For the total contribution of this process, the contribution of the triangular loop formed by $K^{*}\overline{K}K$ particles could generate a triangular singularity of about 1418 MeV. We calculate the differential decay width of this process and show a narrow peak of about 980 MeV in the ${\pi }^{+}{\pi }^{-}$ invariant mass distribution, which comes from $f_0$ decay. For the $M_{\mathrm{inv}}(\pi f_0)$ invariant mass distribution, we obtain a finite peak at 1418 MeV, which is consistent with the triangle singularity.

The production of a heavy quark is accompanied by gluon bremsstrahlung, which is suppressed at small angles $\mathrm{\Theta }\lesssim M_Q/E$ for mass $M_Q$ and high energy $E$, according to perturbative quantum chromodynamics (QCD) (“dead cone effect”). As particles at small angles typically have large momenta, the heavy quark mass also causes a suppression of high momentum particles. In this paper, we studied this effect in $c$- and $b$-quark events using data from Z boson decays in $e^{+}{e}^{-}$ annihilation. The heavy quark fragmentation function for charged particles is reconstructed in the momentum fraction variable $x$ or $\xi =\ln (1/x)$ by removing the decays of the heavy quark hadrons. Indeed, we find an increasing suppression of particles with rising $x$ down to a fraction of $\lesssim 1/10$ for particles with $x\gtrsim 0.2$ in $b$-quark and $x\gtrsim 0.4$ in $c$-quark jets in comparison to light quark fragmentation. The sensitivity to the dead cone effect in the present momentum analysis is considerably increased in comparison to the recently presented angular analysis. This amount of suppression and the differences between $c$- and $b$-quark fragmentation are in good quantitative agreement with the expectations based on perturbative QCD within the modified leading logarithmic approximation (MLLA) in the central kinematic region. The data also support a two parameter description in the MLLA of these phenomena (“limiting spectrum”). The sensitivity of these measurements to the heavy quark mass is investigated.

We present an updated set of SKMHS diffractive parton distribution functions (PDFs). In addition to the diffractive deep-inelastic scattering (diffractive DIS) datasets, the recent diffractive dijet cross-section measurement by the H1 experiment from the HERA collider are added to the data sample. The new set of diffractive PDFs, entitled SKMHS23 and SKMHS23-dijet, are presented at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO) accuracy in perturbative QCD. Since the gluons directly contribute to jet production through the boson-gluon fusion process, the data on diffractive dijet production in inclusive DIS help constrain the gluon density, allowing for the determination of both the quark and gluon densities with better accuracy. The NLO and NNLO theory predictions calculated using both SKMHS23 and SKMHS23-dijet are compared to the analyzed data showing excellent agreement. The effect arising from the inclusion of diffractive dijet data and higher-order QCD corrections on the extracted diffractive PDFs and data/theory agreements are clearly examined and discussed.

We explore the potential of jet observables in charged-current deep inelastic scattering events at the future Electron-Ion Collider. Tagging jets with a recoiling neutrino, which can be identified by the event’s missing transverse momentum, will allow for flavor-sensitive measurements of transverse momentum dependent parton distribution functions. We present the first predictions for transverse-spin asymmetries in azimuthal neutrino-jet correlations and hadron-in-jet measurements. We study the kinematic reach and the precision of these measurements and explore their feasibility using parametrized detector simulations. We conclude that jet production in charged-current deep inelastic scattering, while challenging in terms of luminosity requirements, will complement the Electron-Ion Collider experimental program to study the three-dimensional structure of the nucleon encoded in transverse momentum dependent parton distribution functions.

We revisit the phenomenology of the deep exclusive electroproduction of a lepton pair, i.e. double deeply virtual Compton scattering (DDVCS), in view of new experiments planned in the near future. The importance of DDVCS in the reconstruction of generalized parton distributions (GPDs) in their full kinematic domain is emphasized. Using Kleiss-Stirling spinor techniques, we provide the leading order complex amplitudes for both DDVCS and Bethe-Heithler sub-processes. Such a formulation turns out to be convenient for practical implementation in the PARTONS framework and EpIC Monte Carlo generator that we use in simulation studies.

Direct detection of sub-GeV dark matter (DM) is challenging because the recoil energy of the nuclei or electron from the elastic scattering of a sub-GeV DM off the target can hardly reach the detector threshold. In this paper, we present a new direct detection strategy for sub-MeV DM via the three-body inelastic scattering process, $\mathrm{DM}+\mathrm{DM}+\mathrm{T}\to \eta +\mathrm{T}$, where $\eta$ is either a DM composite state or any dark radiation, $\mathrm{T}$ is the detector target. This process is common for a large class of DM models without presuming particular thermal history in the early Universe. The typical signature from this process is almost a monoenergetic pulse signal where the recoil energy comes from either the binding energy or the consumed DM particle. We show that detectable DM mass range can be effectively enlarged compared to the elastic scattering process.

Measurements of electrons from ${\nu }_e$ interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons.

The time evolution of the averaged energy-momentum tensor as well as its variation with energy density are calculated in a far-from-equilibrium state of $\mathcal{N}=4$ SYM theory undergoing a Bjorken expansion. The calculation is carried out holographically where we consider a collection of trajectories of the energy density in the space of solutions by small changes to the initial conditions of the bulk spacetime. We argue that the proper interpretation of the variation of the diagonal energy momentum tensor components with respect to the energy density is that of a far-from-equilibrium speed of sound. We demonstrate remarkable agreement with a corresponding hydrodynamic prediction. We find by Borel resummation that the holographic system has one attractor for this speed of sound longitudinal, and another transverse to the direction of Bjorken expansion. Attractor times for various initial flow conditions show that reaching an attractor does not imply or require local thermal equilibrium. In the cases studied, reaching an attractor implies hydrodynamization (quantities evolve approximately according to hydrodynamics), justifying the name hydrodynamic attractor.

Exploration of entanglement entropy (EE) and obtaining the Page curve in the context of eternal black holes associated with top-down nonconformal holographic thermal duals at intermediate coupling has been entirely unexplored in the literature. We fill this gap by obtaining the Page curve of an eternal neutral black hole from a doubly holographic setup relevant to the M-theory dual of thermal QCD-like theories at high temperatures (i.e., above $T_c$) and intermediate coupling (effected by inclusion of terms quartic in curvature in M theory). Remarkably, excluding the higher derivative terms, the EE of the Hawking radiation from the on-shell Wald entanglement entropy integral (for appropriate choices of constants of integration appearing in the embeddings) increases almost linearly due to dominance of entanglement entropy contribution from the Hartman-Maldacena (HM)-like surface $S_{\mathrm{EE}}^{\mathrm{HM},{\beta }^0},\beta \sim l_p^6$. This imparts a “Swiss-cheese” structure to $S_{\mathrm{EE}}^{\mathrm{HM},{\beta }^0}$ effecting a “Large N scenario” (LNS). Then after the Page time, the EE contribution from the island surface (IS) $S_{\mathrm{EE}}^{\mathrm{IS},{\beta }^0}$ dominates and saturates the linear time growth of the entanglement entropy of Hawking radiation and leads to the Page curve. The same is also obtained via the areas of the Hartman-Maldacena-like/island surfaces. Requiring the (IS) EE ($S_{\mathrm{EE}}^{\mathrm{IS},{\beta }^0}$) per unit Hawking-Beckenstein entropy ($S_{\mathrm{BH}}$) post the Page time to be around 2, and positivity of the Page time, set respectively a lower and upper bound on the horizon radius $r_h$ (the nonextremality parameter). Further, with the inclusion of the $\mathcal{O}(R^4)$ terms in M theory, the fact the turning point associated with the HM-like surface is in the deep IR, requires a relationship between $l_p$ and $r_h$ along with a conjectural $\gamma \equiv e^{-\mathcal{O}(1)N^{1/3}}$-suppression (motivated by the aforementioned requirement $\frac{S_{\mathrm{EE}}^{\mathrm{IS},{\beta }^0}}{S_{\mathrm{BH}}}\sim 2$ up to leading order). We obtain a hierarchy with respect to $\gamma$ in $S_{\mathrm{EE}}^{\mathrm{HM},{\beta }^0},S_{\mathrm{EE}}^{\mathrm{IS},{\beta }^0}$ and $S_{\mathrm{EE}}^{\mathrm{HM},\beta },S_{\mathrm{EE}}^{\mathrm{HM},\beta }$ [at $\mathcal{O}(\beta )$]. This is due to the existence of massless graviton corresponding to a null mass eigenvalue of the Laplace-Beltrami equation in the internal space.

Supposing the existence of dark fluid with a Chaplygin-like equation of state $p=-B/\rho$ (CDF) as a cosmic background, we obtain a static spherically symmetric black hole (BH) solution to the Einstein gravitational equations. We study the $P-V$ critical behavior of an anti-de Sitter (AdS) BH surrounded by the CDF in the extended phase space where the cosmological constant appears as pressure, and our results show the existence of the van der Waals like small/large BH phase transition. Also, it is found that such a BH displays a first-order low-/high-$\mathrm{\Phi }$ BH phase transition and admits the same criticality with the van der Waals liquid/gas system in the nonextended phase space, where the normalization factor $q$ is considered as a thermodynamic variable, while the cosmological constant is fixed. In both $P-V$ and the newly proposed $q-\mathrm{\Phi }$ phase spaces, we calculate the BH equations of state and then numerically study the corresponding critical quantities. Moreover, the critical exponents are derived, and the results show the universal class of the scaling behavior of thermodynamic quantities near criticality. Finally, we study the shadow thermodynamics of AdS BHs surrounded by the CDF. We find that there exists a positive correlation between the shadow radius and the event horizon radius in our case. By analyzing the temperature and heat capacity curves under the shadow context, we discover that the shadow radius can replace the event horizon radius to demonstrate the BH phase transition process, and the changes of the shadow radius can serve as order parameters for the small/large BH phase transition, indicating that the shadow radius could give us a glimpse into the BH phase structure from the observational point of view.

As some of the most compact stellar objects in the Universe, neutron stars are unique cosmic laboratories. The study of neutron stars provides an ideal theoretical test bed for investigating both physics at supranuclear densities as well as fundamental physics. Their global astrophysical properties however depend strongly on the star’s internal structure, which is currently unknown due to uncertainties in the equation of state. In recent years, a lot of work has revealed the existence of universal relations between stellar quantities that are insensitive to the equation of state. At the same time, the field of multimessenger astronomy has been uniquely expanded with the advent of gravitational wave astronomy, which has recently been making strides towards incorporating machine learning techniques. In this paper, we develop universal relations for rapidly rotating neutron stars, by using supervised machine learning methods, thus proposing a new way of discovering and validating such relations. The analysis is performed for tabulated hadronic, hyperonic, and hybrid equation of state ensembles that obey the multimessenger constraints and cover a wide range of stiffnesses. The relations discussed could provide an accurate tool to constrain the equation of state of nuclear matter when measurements of the relevant observables become available.

In [1], we developed a first-quantized worldline formalism for all-order computations of amplitudes in QED. In particular, we demonstrated in this framework an all-order proof of the infrared safety of the Faddeev-Kulish (FK) $S$-matrix for virtual exchanges in the scattering of charged fermions. In this work, we extend the worldline formalism for both the Dyson and FK $S$-matrix to consider further the emission and absorption of arbitrary numbers of photons. We show how Low’s theorem follows in this framework and derive Weinberg’s theorem for the exponentiation of IR divergences. In particular, we extend our all-order proof of the IR safety of the FK $S$-matrix to both virtual exchanges and real photon emissions. We argue that the worldline approach leads to a modern Wilsonian interpretation of the IR safety of the FK $S$-matrix and provides a novel template for the treatment of IR divergences in real-time problems. Using Grassmannian integration methods, we derive a simple and powerful result for N-th rank vacuum polarization tensors. Applications of these methods will be discussed in follow-up work.

Nuclear reactors represent a promising neutrino source for $\mathrm{CE}\nu \mathrm{NS}$ (coherent-elastic neutrino-nucleus scattering) searches. However, reactor sites also come with high ambient neutron flux. Neutron capture-induced nuclear recoils can create a spectrum that strongly overlaps the $\mathrm{CE}\nu \mathrm{NS}$ signal for recoils $\lesssim 100\mathrm{eV}$ for nuclear reactor measurements in silicon or germanium detectors. This background can be particularly critical for low-power research reactors providing a moderate neutrino flux. In this work we quantify the impact of this background and show that, for a measurement 10 m from a 1 MW reactor, the effective thermal neutron flux should be kept below $\sim 7\times {10}^{-4}\mathrm{n}/{\mathrm{cm}}^2\mathrm{s}$ so that the $\mathrm{CE}\nu \mathrm{NS}$ events can be measured at least at a $5\sigma$ level with germanium detectors in 100 kg yr exposure time. This flux corresponds to 60% of the sea-level flux but needs to be achieved in a nominally high-flux (reactor) environment. Improved detector resolution can help the measurements, but the thermal flux is the key parameter for the sensitivity of the experiment. For silicon detectors, the constraint is even stronger and thermal neutron fluxes must be near an order of magnitude lower. This constraint highlights the need of an effective thermal neutron mitigation strategy for future low threshold $\mathrm{CE}\nu \mathrm{NS}$ searches. In particular, the neutron capture-induced background can be efficiently reduced by active veto systems tagging the deexcitation gamma following the capture.

The recent BESIII data on $J/\psi \to \gamma (K_S{K}_S{\pi }^0)$, which is significantly more precise than earlier $\eta (1405/1475)$-related data, enables quantitative discussions on $\eta (1405/1475)$ at the previously unreachable level. We conduct a three-body unitary coupled-channel analysis of experimental Monte Carlo outputs for radiative $J/\psi$ decays via $\eta (1405/1475)$: $K_S{K}_S{\pi }^0$ Dalitz plot distributions from the BESIII, and branching ratios of $\gamma (\eta {\pi }^{+}{\pi }^{-})$ and $\gamma (\gamma {\pi }^{+}{\pi }^{-})$ final states relative to that of $\gamma (K\overline{K}\pi )$. Our model systematically considers (multi)loop diagrams and an associated triangle singularity, which is critical for making excellent predictions on $\eta (1405/1475)\to \pi \pi \pi$ line shapes and branching ratios. The $\eta (1405/1475)$ pole locations are revealed for the first time. Two poles for $\eta (1405)$ are found on different Riemann sheets of the $K^{*}\overline{K}$ channel, while one pole is found for $\eta (1475)$. The $\eta (1405/1475)$ states are described by two bare states dressed with continuum states. The lower bare state would be an excited ${\eta }^{\prime }$, while the higher one could be an excited ${\eta }^{(\prime )}$, hybrid, glueball, or a mixture of these. This work presents the first-ever pole determination based on a manifestly three-body unitary coupled-channel framework applied to experimental three-body final state distributions (Dalitz plots).

Motivated by exploring the thermalization process in relativistic and nonrelativistic holographic field theories after a nonlocal quench, we investigate some features in the time evolution of the entanglement wedge cross section (EWCS). This quantity is a possible holographic dual to some nonlocal information measures such as entanglement of purification. In particular, we focus on the time dependence of the EWCS during black hole formation in ($D+2$)-dimensional anti–de Sitter spacetime as well as geometries with Lifshitz and hyperscaling-violating exponents. A combination of analytic and numerical results for large symmetric strip shaped boundary subregions shows that the scaling of the EWCS at early times only depends on the Lifshitz exponent. In addition, this early-growth regime is followed by a linear-growth regime whose velocity depends on the dimensions of spacetime, the Lifshitz exponent, and the hyperscaling parameter. This velocity is the same as the entanglement velocity and for nontrivial dynamical exponent depends on the temperature of the final equilibrium state.