We derive new constraints on models of decaying and annihilating dark matter (DM) by requiring that the energy injected into the intergalactic medium (IGM) not overheat it at late times, when measurements of the Lyman-$\alpha$ forest constrain the IGM temperature. We improve upon previous analyses by using the recently developed DarkHistory code package, which self-consistently takes into account additional photoionization and photoheating processes due to reionization and DM sources. Our constraints are robust to the uncertainties of reionization and competitive with leading limits on sub-GeV DM that decays preferentially to electrons [https://github.com/hongwanliu/DarkHistory/tree/T_igm_temperature_constraints].

The Tibet-$\mathrm{AS}\gamma$ Collaboration has recently reported a measurement of diffuse $\gamma$-ray flux from the outer Galactic disk in the energy range reaching PeV. We complement this measurement with the Fermi/LAT measurement of the diffuse flux from the same sky region and study the pion decay model of the combined $\mathrm{Fermi}/\mathrm{LA}\mathrm{T}+\mathrm{Tibet}\text{−}\mathrm{AS}\gamma$ spectrum. We find that within such a model the average cosmic-ray spectrum in the outer Galactic disk has the same characteristic features as the local cosmic-ray spectrum. In particular, it experiences a hardening at several hundred GV rigidity and a knee feature in the PV rigidity range. The slope of the average cosmic-ray spectrum above the break is close to the locally observed slope of the helium spectrum $\gamma \simeq 2.5$, but is harder than the slope of the local proton spectrum in the same rigidity range. Although the combination of Fermi/LAT and Tibet-$\mathrm{AS}\gamma$ data points to the presence of the knee in the average cosmic-ray spectrum, the quality of the data is not yet sufficient for the study of knee shape and cosmic-ray composition.

We present a novel way of wavefront sensing using a commercially available, continuous-wave time-of-flight camera with quarter video graphics array resolution. This CMOS phase camera is capable of sensing externally modulated light sources with frequencies up to 100 MHz. The high-spatial-resolution of the sensor, combined with our integrated control electronics, allows the camera to image power modulation index as low as $-62\mathrm{dBc}/\sec /\mathrm{pixel}$. The phase camera is applicable to problems where alignment and mode-mismatch sensing is needed and suited for diagnostic and control applications in gravitational-wave detectors. Specifically, we explore the use of the phase camera in sensing the beat signals due to thermal distortions from pointlike heat absorbers on the test masses in the Advanced LIGO detectors. The camera is capable of sensing optical path distortions greater than about 2 nm in the Advanced LIGO input mirrors, limited by the phase resolution. In homodyne readout, the performance can reach up to 0.1 nm, limited by the modulation amplitude sensitivity.

Muon decay is self-analyzing; the spectral-angular distribution of the emitted electron reveals the spin orientation of the polarized muon. Here, we show that the same feature applies to muons in nonplane-wave states and helps reveal the rich polarization opportunities available. We focus on the so-called vortex states, in which the muon carries a nonzero orbital angular momentum with respect to the average propagation direction and exhibits a cone structure in the momentum distribution. We compute the spectrum and the angular distribution of the electrons emitted in decays of vortex muons and show that the most revealing observable is not the angular distribution but the fixed-angle electron spectra. Even for very small cone opening angles of the vortex muons, it will be easy to observe significant modifications of the electron spectra which would allow one to distinguish vortex muons from approximately plane-wave muons, as well as to differentiate among various polarization states. These features will be the key to tracking the evolution of vortex muons in external magnetic fields.

Self-destructing dark matter (SDDM) is a class of dark sector models in which the collision of a dark sector particle with the earth induces its prompt decay into Standard Model particles, generating unique signals at neutrino detectors. The inherent fragility of SDDM makes its survival from the early Universe unlikely, implying a late time production mechanism. We present an efficient late time production mechanism for SDDM based on atomic rearrangement, the mechanism responsible for muon or antiproton capture in hydrogen. In this model, an atomic rearrangement process occurs in our Galaxy, converting dark atoms into highly excited bound states—our SDDM candidates. While the resulting SDDM is only a small fraction of the dark matter flux, its striking self-destruction signals imply a significant discovery reach in the existing data from the Super-Kamiokande experiment.

Extensions to the Standard Model that use strictly off-shell degrees of freedom—the fakeons—allow for new measurable interactions at energy scales usually precluded by the constraints that target the on-shell propagation of new particles. Here we employ the interactions between a new fake scalar doublet and the muon to explain the recent Fermilab measurement of its anomalous magnetic moment. Remarkably, unlike in the case of usual particles, the experimental result can be matched for fakeon masses below the electroweak scale without contradicting the stringent precision data and collider bounds on new light degrees of freedom. Our analysis, therefore, demonstrates that the fakeon approach offers unexpected viable possibilities to model new physics naturally at low scales.

Modern advances in algorithms for lattice QCD calculations have steadily driven down the resources required to generate gauge field ensembles and calculate quark propagators, such that, in cases relevant to nuclear physics, performing quark contractions to assemble correlation functions from propagators has become the dominant cost. This work explores a propagator sparsening algorithm for forming correlation functions describing multihadron systems, such as light nuclei, with reduced computational cost. The algorithm constructs correlation functions from sparsened propagators defined on a coarsened lattice geometry, where the sparsened propagators are obtained from propagators computed on the full lattice. This algorithm is used to study the low-energy QCD ground-state spectrum using a single Wilson-clover lattice ensemble with $m_{\pi }\approx 800\mathrm{MeV}$. It is found that the extracted ground state masses and binding energies, as well as their statistical uncertainties, are consistent when determined from correlation functions constructed from sparsened and full propagators. In addition, while evidence of modified couplings to excited states is observed in sparsened correlation functions, it is demonstrated that these effects can be removed, if desired, with an inexpensive modification to the sparsened estimator.

Lattice gauge theory is an essential tool for strongly interacting non-Abelian fields, such as those in quantum chromodynamics where lattice results have been of central importance for several decades. Recent studies suggest that quantum computers could extend the reach of lattice gauge theory in dramatic ways, but the usefulness of quantum annealing hardware for lattice gauge theory has not yet been explored. In this work, we implement SU(2) pure gauge theory on a quantum annealer for lattices comprising a few plaquettes in a row with a periodic boundary condition. These plaquettes are in two spatial dimensions and calculations use the Hamiltonian formulation where time is not discretized. Numerical results are obtained from calculations on D-Wave Advantage hardware for eigenvalues, eigenvectors, vacuum expectation values, and time evolution. The success of this initial exploration indicates that the quantum annealer might become a useful hardware platform for some aspects of lattice gauge theories.

We propose a new type of structure for singly heavy baryons of $Qqq\overline{q}q$ in addition to the conventional one of $Qqq$. Based on chiral symmetry of the light quarks, we show that the $Qqq\overline{q}q$ baryon offers a novel picture for heavy-quark spin-singlet and flavor-antisymmetric baryons. By making use of the effective Lagrangian approach, we find that ${\mathrm{\Lambda }}_c(2765)$ and ${\mathrm{\Xi }}_c(2967)$ are mostly $Qqq\overline{q}q$, while ${\mathrm{\Lambda }}_c(2286)$ and ${\mathrm{\Xi }}_c(2470)$ are mostly $Qqq$. The masses of negative-parity baryons are predicted. We also derive a sum rule and the extended Goldberger-Treiman relation that the masses of the baryons satisfy. Furthermore, a mass degeneracy of parity partners of the baryons with the restoration of chiral symmetry is discussed. These are the unique features that the conventional picture of radial excitation in the quark model does not accommodate. Our findings provide useful information not only for future experiments but also for future lattice simulations on diquarks.

In the $B^{+}\to D^{+}{D}^{-}{K}^{+}$ decay, LHCb has reported the observation of the open-charm exotic states $X_{0,1}^0\equiv X_{0,1}(2900{)}^0$ with four different quark flavors $(ud\overline{s}\overline{c})$, where the subscripts (0,1) denote the spins. To confirm the discovery, we propose ${\mathrm{\Lambda }}_b\to {\mathrm{\Sigma }}_c^{0(++)}{X}_{0,1}^{\prime 0(--)}$ in the final state interaction, where $X_{0,1}^{\prime 0(--)}$ with $su\overline{d}\overline{c}$ ($ds\overline{u}\overline{c}$) are the new $X_{0,1}$-like exotic states. More specifically, ${\mathrm{\Lambda }}_c^{+}{D}_s^{-}$ in ${\mathrm{\Lambda }}_b\to {\mathrm{\Lambda }}_c^{+}{D}_s^{-}$ are transformed as ${\mathrm{\Sigma }}_c^{0(++)}{X}_{0,1}^{\prime 0(--)}$, by exchanging ${\pi }^{+(-)}$. As the order of magnitude estimates, we calculate $\mathcal{B}({\mathrm{\Lambda }}_b\to {\mathrm{\Sigma }}_c^{0(++)}{X}_{0,1}^{\prime 0(--)})=(2.3\pm 0.6,4.3\pm 0.8_{-2.5}^{+3.3})\times {10}^{-4}$. In addition, we estimate other $b$-baryon decays with the $X_{0,1}$-like states, such as $\mathcal{B}({\mathrm{\Xi }}_b^{0(-)}\to {\mathrm{\Xi }}_c^{0(+)}(2645)X_0^{\prime 0(--)},{\mathrm{\Lambda }}_b\to {\mathrm{\Xi }}_c^{\prime 0}{X}_{0,1}^0)\sim {10}^{-5}$. While one needs ${\mathrm{\Lambda }}_b\to {\mathrm{\Sigma }}_c^{0(++)}{M}_{c}M$ to observe $X_{0,1}^{\prime 0(--)}\to M_{c}M$ with $M_{c}M=D_s^{-}{\pi }^{+}$, ${\overline{D}}^0{\overline{K}}^0$ $(D_s^{-}{\pi }^{-}$, $D^{-}{K}^{-})$, $\mathcal{B}({\mathrm{\Lambda }}_b\to {\mathrm{\Sigma }}_c^{0(++)}{X}_{0,1}^{\prime 0(--)},X_{0,1}^{\prime 0(--)}\to M_{c}M)\sim {10}^{-4}$ are accessible to the LHCb experiment.

We report on the expected sensitivity of dedicated scintillator-based detectors at the LHC for elementary particles with charges much smaller than the electron charge. The dataset provided by a prototype scintillator-based detector is used to characterize the performance of the detector and provide an accurate background projection. Detector designs, including a novel slab detector configuration, are considered for the data taking period of the LHC to start in 2022 (Run 3) and for the high luminosity LHC. With the Run 3 dataset, the existence of new particles with masses between 10 MeV and 45 GeV could be excluded at 95% confidence level for charges between 0.003 e and 0.3 e, depending on their mass. With the high luminosity LHC dataset, the expected limits would reach between 10 MeV and 80 GeV for charges between 0.0018 e and 0.3 e, depending on their mass.

By analyzing $6.32{\mathrm{fb}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we determine the branching fraction of the leptonic decay $D_s^{+}\to {\tau }^{+}{\nu }_{\tau }$, with ${\tau }^{+}\to {\pi }^{+}{\pi }^0{\overline{\nu }}_{\tau }$, to be ${\mathcal{B}}_{D_s^{+}\to {\tau }^{+}{\nu }_{\tau }}=(5.29\pm {0.25}_{\mathrm{stat}}\pm {0.20}_{\mathrm{syst}})\%$. We estimate the product of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ and the $D_s^{+}$ decay constant $f_{D_s^{+}}$ to be $f_{D_s^{+}}|V_{cs}|=(244.8\pm {5.8}_{\mathrm{stat}}\pm {4.8}_{\mathrm{syst}})\mathrm{MeV}$, using the known values of the ${\tau }^{+}$ and $D_s^{+}$ masses as well as the $D_s^{+}$ lifetime, together with our branching fraction measurement. Combining the value of $|V_{cs}|$ obtained from a global fit in the standard model and $f_{D_s^{+}}$ from lattice quantum chromodynamics, we obtain $f_{D_s^{+}}=(251.6\pm {5.9}_{\mathrm{stat}}\pm {4.9}_{\mathrm{syst}})\mathrm{MeV}$ and $|V_{cs}|=0.980\pm {0.023}_{\mathrm{stat}}\pm {0.019}_{\mathrm{syst}}$. Using the branching fraction of ${\mathcal{B}}_{D_s^{+}\to {\mu }^{+}{\nu }_{\mu }}=(5.35\pm 0.21)\times {10}^{-3}$, we obtain the ratio of the branching fractions ${\mathcal{B}}_{D_s^{+}\to {\tau }^{+}{\nu }_{\tau }}/{\mathcal{B}}_{D_s^{+}\to {\mu }^{+}{\nu }_{\mu }}=9.89\pm 0.71$, which is consistent with the standard model prediction of lepton flavor universality.

The mono-photon signature emerging in an ${\mathrm{E}}_6$ supersymmetric standard model (${\mathrm{E}}_6\mathrm{SSM}$) from inert Higgsino dark matter (DM) is analyzed at future $e^{+}{e}^{-}$ colliders. As the inert neutral and charged Higgsinos are nearly degenerate, the inert chargino is a rather long lived particle and the charged particle associated with its decay to the inert Higgsino is quite soft. We show that the pair production of inert charginos at a 500 GeV electron-positron collider with an initial or final state photon is the most promising channel for probing the inert Higgsino as one DM candidate within the ${\mathrm{E}}_6\mathrm{SSM}$. We also emphasize that this signal has no chance of being observed at the Large Hadron Collider (LHC) with higher energy and/or luminosity. Finally, we remark that, combined with a DM signal produced in direct detection (DD) experiments involving an active Higgsino state as the second DM candidate, this dual evidence could point to a two-component DM version of the ${\mathrm{E}}_6\mathrm{SSM}$.

In this work we study static black holes in the regularized 4D Einstein-Gauss-Bonnet theory of gravity; a shift-symmetric scalar-tensor theory that belongs to the Horndeski class. This theory features a simple black hole solution that can be written in closed form, and which we show is the unique static, spherically symmetric and asymptotically flat black hole vacuum solution of the theory. We further show that no asymptotically flat, time-dependent, spherically symmetric perturbations to this geometry are allowed, which suggests that it may be the only spherically symmetric vacuum solution that this theory admits (a result analogous to Birkhoff’s theorem). Finally, we consider the thermodynamic properties of these black holes, and find that their final state after evaporation is a remnant with a size determined by the coupling constant of the theory. We speculate that remnants of this kind from primordial black holes could act as dark matter, and we constrain the parameter space for their formation mass, as well as the coupling constant of the theory.

It is challenging to construct explicit and controllable models that realize de Sitter solutions in string compactifications. This difficulty is the main motivation for the refined de Sitter conjecture and the trans-Planckian censorship conjecture which forbid stable de Sitter solutions but allow metastable, unstable and rolling solutions in a theory consistent with quantum gravity. Inspired by this, we first study a toy de Sitter no-scale supergravity model and show that for particular choices of parameters it can be consistent with the refined de Sitter conjecture and the trans-Planckian censorship conjecture. Then we modify the model by adding rolling dynamics and show that the theory can become stable along the imaginary direction, where it would otherwise be unstable. We extend the model to multifield rolling and de Sitter fields, finding the parameter space where they can be compatible with the refined de Sitter conjecture. The modified models with rolling fields can be used to construct quintessence models to accommodate the accelerating expansion of the Universe.

The present work aims to explore the model given by Lanczos-Lovelock gravity theories indexed by a fixed integer to require a unique anti–de Sitter vacuum, dressed by a scalar field nonminimal coupling. For this model, we add a special matter source characterized by a nonlinear Maxwell field coupling with a function depending on the scalar field. Computing its thermodynamics parameters by using the Euclidean action, we obtain interesting and nonzero thermodynamical quantities, unlike its original version, allowing to analyze thermodynamical stability. Together with the above, we find that these solutions satisfy the first law of thermodynamics as well as a Smarr relation.

In this work we show that Einstein gravity in four dimensions can be consistently obtained from the compactification of a generic higher curvature Lovelock theory in dimension $D=4+p$, ($\mathrm{p}\ge 1$). The compactification is performed on a direct product space ${\mathcal{M}}_D={\mathcal{M}}_4\times {\mathcal{K}}^p$, where ${\mathcal{K}}^p$ is a Euclidean internal manifold of constant curvature. The process is carried out in such a way that no fine tuning between the coupling constants is needed. The compactification requires us to dress the internal manifold with the flux of suitable $p$-forms whose field strengths are proportional to the volume form of the internal space. We explicitly compactify Einstein-Gauss-Bonnet theory from dimension six to Einstein theory in dimension four and sketch out a similar procedure for this compactification to take place starting from dimension five. Several black $\mathrm{string}/p$-branes solutions are constructed, among which, a five dimensional asymptotically flat black string composed of a Schwarzschild black hole on the brane is particularly interesting. Finally, the thermodynamic of the solutions is described and we find that the consistent compactification modifies the entropy by including a constant term, which may induce a departure from the usual behavior of the Hawking-Page phase transition. New scenarios are possible in which large black holes dominate the canonical ensemble for all temperatures above the minimal value.

The graphical calculus method is generalized to study the relation between covariant and canonical dynamics of loop quantum gravity. On one hand, a graphical derivation of the partition function of the generalized Euclidean Engle-Pereira-Rovelli-Livine (EPRL) spin-foam model is presented. On the other hand, the action of a Euclidean Hamiltonian constraint operator on certain spin network states is calculated by graphical method. It turns out that the EPRL model can provide a rigging map such that the Hamiltonian constraint operator is weakly satisfied on certain physical states for the Immirzi parameter $\beta =1$. In this sense, the quantum dynamics between the covariant and canonical formulations are consistent to each other.

The first law of black hole thermodynamics in the presence of a cosmological constant $\mathrm{\Lambda }$ can be generalized by introducing a term containing the variation $\delta \mathrm{\Lambda }$. Similar to other terms in the first law, which are variations of some conserved charges like mass, entropy, angular momentum, electric charge, etc., it has been shown [Classical Quant. Grav. 35, 125012 (2018)] that the new term has the same structure: $\mathrm{\Lambda }$ is a conserved charge associated with a gauge symmetry; and its role in the first law is quite similar to an “electric charge” rather than to the pressure. Besides, its conjugate chemical potential resembles an “electric potential” on the horizon, in contrast with the volume enclosed by horizon. In this work, first we propose and prove the generalized Smarr relation in this new paradigm. Then, we reproduce systematically the “effective volume” of a black hole which has been introduced before in the literature as the conjugate of pressure. Our construction removes the ambiguity in the definition of volume. Finally, we apply and investigate this formulation of “$\mathrm{\Lambda }$ as a charge” on a number of solutions to different models of gravity for different spacetime dimensions. Especially, we investigate the applicability and validity of the analysis for black branes, whose enclosed volume is not well defined in principle.

We perform numerical simulations of gravitational waves (GWs) induced by hydrodynamic and hydromagnetic turbulent sources that might have been present at cosmological quantum chromodynamic (QCD) phase transitions. For turbulent energies of about 4% of the radiation energy density, the typical scale of such motions may have been a sizable fraction of the Hubble scale at that time. The resulting GWs are found to have an energy fraction of about ${10}^{-9}$ of the critical energy density in the nHz range today and may already have been observed by the NANOGrav Collaboration. This is further made possible by our findings of shallower spectra proportional to the square root of the frequency for nonhelical hydromagnetic turbulence. This implies more power at low frequencies than for the steeper spectra previously anticipated. The behavior toward higher frequencies depends strongly on the nature of the turbulence. For vortical hydrodynamic and hydromagnetic turbulence, there is a sharp drop of spectral GW energy by up to five orders of magnitude in the presence of helicity, and somewhat less in the absence of helicity. For acoustic hydrodynamic turbulence, the sharp drop is replaced by a power law decay, albeit with a rather steep slope. Our study supports earlier findings of a quadratic scaling of the GW energy with the magnetic energy of the turbulence and inverse quadratic scaling with the peak frequency, which leads to larger GW energies under QCD conditions.