The electronic energy deposited on nuclear emulsions by C ions of 5–200 keV and Kr ions of 5–600 keV is evaluated and compared with those deposited by fast ions for designing and fabricating fine-grain nuclear emulsions for directional dark matter searches. The nuclear quenching factor and the electronic linear energy transfer, which refers to the specific electronic energy deposited along the ion track, are evaluated. The so-called core and penumbra of heavy-ion track structure is modified to understand the track caused by recoil ions produced by dark matter candidate, i.e., weakly interacting massive particles, striking a nucleus in the AgBr crystal of nuclear emulsion. Very heavy recoil ions, 100–180 keV Pb ions, produced in $\alpha$ decay are also studied. Furthermore, the track structures due to protons of 25–80 keV are evaluated to consider the influence of background neutrons in underground laboratories.

The $pp\to \{W,W^{\prime }\}\to l\nu$ and $pp\to \{\gamma ,Z,Z^{\prime }\}\to l^{+}{l}^{-}$ ($l=e$, $\mu$) processes in the $SU(3{)}_C\times SO(5)\times U(1{)}_X$ gauge-Higgs unification (GHU) models are studied, where $W^{\prime }$ and $Z^{\prime }$ bosons are Kaluza-Klein (KK) exited states of the electroweak gauge bosons. From the experimental data collected at the Large Hadron Collider, constraints on the KK mass scale and the Aharonov-Bohm phase are obtained. One can explore the KK mass scale in the grand unified theory inspired GHU model up to 18 TeV for the luminosity $300{\mathrm{fb}}^{-1}$ and 22 TeV for the luminosity $3000{\mathrm{fb}}^{-1}$ at $\sqrt{s}=14\mathrm{TeV}$.

We study the exclusive two-body nonleptonic $B_c\to X_{c\overline{c}}M$ decays, where $X_{c\overline{c}}$ is either a ground ($1S$) or a radially excited ($2S$ or $3S$) charmonium, and $M$ is a pseudoscalar ($P$) or a vector ($V$) meson. We consider here three categories of decays: $B_c\to PP,PV,VP$ decays within the framework of a relativistic independent quark (RIQ) model based on a flavor-independent interaction potential in scalar-vector harmonic form. Using the factorization approximation, we calculate the weak form factors from the overlapping integrals of meson wave functions obtained in the RIQ model and predict the branching fractions for a set of exclusive nonleptonic $B_c$ decays in reasonable agreement with other model predictions. Some of the decays of interest are found to have branching fractions $\sim ({10}^{-3}-{10}^{-4})$ within the detection ability of the current experiments and can be precisely measured at LHCb in the near future. In the wake of the recent measurement of $B_c\to J/\psi \pi (K)$, $B_c\to J/\psi \pi (D_s)$, $B_c\to \pi (J/\psi ,\psi (2S))$, and $B_c\to J/\psi (\pi ,\mu \nu )$ reported by the LHCb and ATLAS Collaborations, we predict the ratios ${\mathcal{R}}_{K/\pi }$, ${\mathcal{R}}_{D_s/\pi }$ and ${\mathcal{R}}_{\psi (2S)/J/\psi }$ in broad agreement with the data from LHCb and ATLAS Collaborations. Our predicted ratio ${\mathcal{R}}_{\pi /\mu \nu }$ is found to be underestimated. The results indicate that the present approach works well in the description of exclusive nonleptonic $B_c$ decays within the framework of the RIQ model.

We describe a novel application of the end-to-end deep learning technique to the task of discriminating top quark-initiated jets from those originating from the hadronization of a light quark or a gluon. The end-to-end deep learning technique uses low-level detector representation of high-energy collision event as inputs to deep learning algorithms. In this study, we use low-level detector information from the simulated Compact Muon Solenoid (CMS) open data samples to construct the top jet classifiers. To optimize classifier performance we progressively add low-level information from the CMS tracking detector, including pixel detector reconstructed hits and impact parameters, and demonstrate the value of additional tracking information even when no new spatial structures are added. Relying only on calorimeter energy deposits and reconstructed pixel detector hits, the end-to-end classifier achieves an area under the receiver operator curve (AUC) score of $0.975\pm 0.002$ for the task of classifying boosted top quark jets. After adding derived track quantities, the classifier AUC score increases to $0.9824\pm 0.0013$, serving as the first performance benchmark for these CMS open data samples.

We present a search for axionlike particles, $a$, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the $a$-gluon coupling is dominant. The search uses $a\to \gamma \gamma$ and $a\to {\pi }^{+}{\pi }^{-}{\pi }^0$ decays, and a data sample corresponding to an integrated luminosity of $168{\mathrm{pb}}^{-1}$ collected with the GlueX detector. The search for $a\to \gamma \gamma$ decays is performed in the mass range of $180<m_a<480\mathrm{MeV}$, while the search for $a\to {\pi }^{+}{\pi }^{-}{\pi }^0$ decays explores the $600<m_a<720\mathrm{MeV}$ region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the $a$-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered.

A light $Z^{\prime }$ vector boson coupled to the second and third lepton generations through the $L_{\mu }-L_{\tau }$ current with mass below 200 MeV provides a very viable explanation in terms of new physics to the recently confirmed $(g-2{)}_{\mu }$ anomaly. This boson can be produced in the bremsstrahlung reaction $\mu N\to \mu N{Z}^{\prime }$ after a high energy muon beam collides with a target. $\mathrm{NA}64\mu$ is a fixed-target experiment using a 160 GeV muon beam from the CERN Super Proton Synchrotron accelerator looking for $Z^{\prime }$ production and its subsequent decays, $Z^{\prime }\to \mathrm{invisible}$. In this paper, we present the study of the $\mathrm{NA}64\mu$ sensitivity to search for such a boson. This includes a realistic beam simulation, a detailed description of the detectors and a discussion about the main potential background sources. A pilot run is scheduled in order to validate the simulation results. If those are confirmed, $\mathrm{NA}64\mu$ will be able to explore all the remaining parameter space which could provide an explanation for the $g-2$ muon anomaly in the $L_{\mu }-L_{\tau }$ model.

We provide a setup by which one can recover the geometry of spacetime from local measurements of quantum particle detectors coupled to a quantum field. Concretely, we show how one can recover the field’s correlation function from measurements on the detectors. Then, we are able to recover the invariant spacetime interval from the measurement outcomes, and hence reconstruct a notion of spacetime metric. This suggest that quantum particle detectors are the experimentally accessible devices that could replace the classical “rulers” and “clocks” of general relativity.

We study supersymmetric ${\mathrm{AdS}}_5\times \mathrm{\Sigma }$ solutions, for $\mathrm{\Sigma }$ being a topological disk with nontrivial $U(1)$ holonomy at the boundary or “half-spindle,” in seven-dimensional $N=2$ gauged supergravity coupled to three vector multiplets. We consider compact and noncompact gauge groups, $SO(4-p,p)$, for $p=0$, 1, 2, and find a number of ${\mathrm{AdS}}_5\times \mathrm{\Sigma }$ solutions with $SO(2)\times SO(2)$ and $SO(2{)}_{\mathrm{diag}}$ residual symmetry from $SO(4)$ and $SO(2,2)$ gauge groups. We also find an $SO(2{)}_R\subset SO(3{)}_R\sim SU(2{)}_R$ symmetric solution, which can be regarded as a solution of pure $N=2$ gauged supergravity with the $SO(3{)}_R$ gauge group and all the fields from vector multiplets vanishing. The solutions preserve $\frac{1}{2}$ of the original $N=2$ supersymmetry and could be interpreted as supergravity duals of $N=1$ superconformal field theories in four dimensions. In particular, some of these solutions can be embedded in ten or eleven dimensions, in which a description in terms of five-branes wrapped on a topological disk can be given.

We study the Page curve and the information paradox for the Bañados-Teiteboim-Zanelli black hole coupled to two thermal baths by applying the island paradigm. We prove that as the island locates outside the event horizon, the entanglement entropy of Hawking radiation for finite temperature black holes obeys the Page curve. However, for extremal rotating black holes, the Page time and the scrambling time become divergent. To avoid the ill-defined nature of the Page time, we consider the contribution of superradiance, which is a process that can extract rotational energy from black holes. The superradiance continues in a period much shorter than the Page time when the central charge $c$ is not too large. In this process, the Page time, the scrambling time and the black hole thermal entropy all decrease. Whenever the superradiance finishes, the black hole turns out to be a neutral black hole and the Hawking radiation dominates. The Page curve can then be well reproduced.

We investigate the $SO(5)$ Landau problem in the $SO(4)$ monopole gauge field background by applying the techniques of the non-linear realization of quantum field theory. The $SO(4)$ monopole carries two topological invariants, the second Chern number and a generalized Euler number, specified by the $SU(2)$ monopole and antimonopole indices, $I_{+}$ and $I_{-}$. The energy levels of the $SO(5)$ Landau problem are grouped into $\mathrm{Min}(I_{+},I_{-})+1$ sectors, each of which holds Landau levels. In the $n$-sectors, $N$th Landau level eigenstates constitute the $SO(5)$ irreducible representation with $(p,q{)}_5=(N+I_{+}+I_{-}-n,N+n{)}_5$ whose function form is obtained from the $SO(5)$ nonlinear realization matrix. In the $n=0$ sector, the emergent quantum geometry of the lowest Landau level is identified as the fuzzy four-sphere with radius being proportional to the difference between $I_{+}$ and $I_{-}$. The Laughlin-like wavefunction is constructed by imposing the $SO(5)$ lowest Landau level projection to the many-body wavefunction made of the Slater determinant. We also analyze the relativistic version of the $SO(5)$ Landau model to demonstrate the Atiyah-Singer index theorem in the $SO(4)$ gauge field configuration.

We revisit a class of non-Hermitian topological models that are Galois conjugates of their Hermitian counter parts. Particularly, these are Galois conjugates of unitary string-net models. We demonstrate that these models necessarily have real spectra, and that topological numbers are recovered as matrix elements of operators evaluated in appropriate biorthogonal basis, that we conveniently reformulate as a concomitant Hilbert space here. We also compute in the biorthogonal basis the topological entanglement entropy, demonstrating that its real part is related to the quantum dimension of the topological order. While we focus mostly on the Yang-Lee model, the results in the paper apply generally to Galois conjugates.

In the present paper we take a step toward the generalization of the post-Newtonian formalism to tensor-multiscalar theories. These are theories where we have more than one scalar field being mediators of the gravitational interaction in addition to the spacetime metric. They are very natural extensions of Einstein’s gravity allowing for the existence of new classes of compact objects and offering interesting phenomenology reaching far beyond the single scalar field theories. We calculate the expansion up to 2.5 post-Newtonian order in the near zone using the so-called direct integration of the relaxed Einstein equations formalism and derive the equation of motion. This work is the first step toward the calculation of gravitational waveforms in tensor-multiscalar theories.

When modified theories of gravity are considered, at most six gravitational wave polarization modes are allowed and classified in tensor modes, the only ones predicted by general relativity (GR), along with additional vector and scalar modes. Therefore, gravitational waves represent a powerful tool to test alternative theories of gravitation. In this paper, we forecast the sensitivity of third-generation ground-based interferometers, Einstein Telescope and Cosmic Explorer, to non-GR polarization modes focusing on the stochastic gravitational wave background. We consider the latest technical specifications of the two independent detectors and the full network in order to estimate both the optimal signal-to-noise ratio and the detectable energy density limits relative to all polarization modes in the stochastic background for several locations on Earth and orientations of the two observatories. By considering optimal detector configurations, we find that in 5 years of observation the detection limit for tensor and extra polarization modes could reach $h_0^2{\mathrm{\Omega }}_{\mathrm{GW}}^{T,V,S}\approx {10}^{-12}-{10}^{-11}$, depending on the network configuration and the stochastic background (i.e., if only one among vector and scalar modes exists or both are present). This means that the network sensitivity to different polarization modes can be approximately improved by a factor ${10}^3$ with respect to second-generation interferometers. We finally discuss the possibility of breaking the scalar modes degeneracy by considering both detectors angular responses to sufficiently high gravitational wave frequencies.

Recent weak-lensing surveys have revealed that the direct measurement of the parameter combination $S_8\equiv {\sigma }_8({\mathrm{\Omega }}_m/0.3{)}^{0.5}$—where ${\sigma }_8$ is a measure of the amplitude of matter fluctuations on $8h^{-1}\mathrm{Mpc}$ scales—is $\sim 3\sigma$ discrepant with the value reconstructed from cosmic microwave background (CMB) data assuming the $\mathrm{\Lambda }$-cold dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) model. In this article, we show that it is possible to resolve the tension if dark matter (DM) decays with a lifetime of ${\mathrm{\Gamma }}^{-1}\simeq 55\mathrm{Gyrs}$ into one massless and one massive product, and transfers a fraction $ϵ\simeq 0.7\%$ of its rest mass energy to the massless component. The velocity kick received by the massive daughter leads to a suppression of gravitational clustering below its free-streaming length, thereby reducing the ${\sigma }_8$ value as compared to that inferred from the standard $\mathrm{\Lambda }\mathrm{CDM}$ model, in a similar fashion to massive neutrino and standard warm DM. Contrarily to the latter scenarios, the time dependence of the power suppression and the free-streaming scale allows the 2-body decaying DM scenario to accommodate CMB, baryon acoustic oscillation, growth factor and uncalibrated supernova Ia data. We briefly discuss implications for DM model building, galactic small-scale structure problems and the recent Xenon-1T excess. Future experiments measuring the growth factor to high accuracy at $0\lesssim z\lesssim 1$ can further test this scenario.

We propose an analytical parametrization of the comoving distance and Hubble parameter to study the cosmic expansion history beyond the vanilla $\mathrm{\Lambda }\mathrm{CDM}$ model. The parametrization is generalized enough to include the contribution of spatial curvature and to capture the higher redshift behaviors. With this parametrization, we study the late-time cosmic behavior and put constraints on the cosmological parameters like present values of Hubble parameter ($H_0$), matter-energy density parameter (${\mathrm{\Omega }}_{\mathrm{m}0}$), spatial curvature energy density parameter (${\mathrm{\Omega }}_{\mathrm{k}0}$), and baryonic matter-energy density parameter (${\mathrm{\Omega }}_{\mathrm{b}0}$) using different combinations data like CMB (cosmic microwave background), BAO (baryon acoustic oscillation), and SN (Pantheon sample for type Ia supernovae). We also rigorously study the Hubble tension in the framework of late time modification from the standard $\mathrm{\Lambda }\mathrm{CDM}$ model. We find that the late time modification of the cosmic expansion can solve the Hubble tension between CMB and SHOES (local distance ladder observation for $H_0$), between $\mathrm{CMB}+\mathrm{BAO}$ and SHOES and between $\mathrm{CMB}+\mathrm{SN}$ and SHOES, but the late time modification cannot solve the Hubble tension between $\mathrm{CMB}+\mathrm{BAO}+\mathrm{SN}$ and SHOES. That means CMB, BAO, and SN data combined put strong enough constraints on $H_0$ (even with varying ${\mathrm{\Omega }}_{\mathrm{k}0}$) and on other background cosmological parameters so that the addition of $H_0$ prior from SHOES (or from similar other local distance observations) cannot significantly pull the $H_0$ value toward the corresponding SHOES value.

We simulate the gravitational dynamics of a massive object interacting with ultralight/fuzzy dark matter (ULDM/FDM), nonrelativistic quantum matter described by the Schrödinger-Poisson equation. We first consider a point mass moving in a uniform background, and then a supermassive black hole (SMBH) moving within a ULDM soliton. After replicating simple dynamical friction scenarios to verify our numerical strategies, we demonstrate that the wake induced by a moving mass in a uniform medium may undergo gravitational collapse that dramatically increases the drag force, albeit in a scenario unlikely to be encountered astrophysically. We broadly confirm simple estimates of dynamical friction timescales for a black hole at the center of a halo but see that a large moving point mass excites coherent “breathing modes” in a ULDM soliton. These can lead to “stone skipping” trajectories for point masses which do not sink uniformly toward the center of the soliton, as well as stochastic motion near the center itself. These effects will add complexity to SMBH-ULDM interactions and to SMBH mergers in a ULDM universe.

The solar disk is among the brightest $\gamma$-ray sources in the sky. It is also among the most mysterious. No existing model fully explains the luminosity, spectrum, time variability, and morphology of its emission. We perform the first analysis of solar disk $\gamma$-rays over a full 11 year solar cycle, utilizing a powerful new method to differentiate solar signals from astrophysical backgrounds. We produce: (i) a robustly measured spectrum from 100 MeV to 100 GeV, reaching a precision of several percent in the 1–10 GeV range, (ii) new results on the anticorrelation between solar activity and $\gamma$-ray emission, (iii) strong constraints on short-timescale variability, ranging from hours to years, and (iv) new detections of the equatorial and polar morphologies of high-energy $\gamma$-rays. We find no significant energy dependence in the time variability of solar disk emission, indicating that strong magnetic-field effects close to the solar surface, rather than modulation throughout the heliosphere, must primarily control the flux and morphology of solar disk emission.

This paper presents a novel method for laser frequency stabilization in the Laser Interferometer Space Antenna (LISA) mission by locking a laser to two stable length references-the arms of the interferometer and an on-board optical cavity. The two references are digitally fused using carefully designed control systems, attempting minimal or no changes to the baseline LISA mission hardware. The interferometer arm(s) provides the most stable reference available in the LISA science band (0.1 mHz–1 Hz), while the cavity sensor’s wideband and linear readout enables additional control system gain below and above the LISA band. The main technical issue with this dual sensor approach is the undesirable slow laser frequency pulling which couples into the control system with the imperfect knowledge of the Doppler shift of the light due to relative spacecraft motion along the LISA arm. This paper outlines requirements on the Doppler shift knowledge to maintain the cavity well within the resonance when activating the fused control system. Two Doppler shift estimation methods are presented that use the already on-board measurements, the inter-spacecraft interferometer link (the main science measurement), and the absolute inter-spacecraft laser ranging system. Both methods reach the required precision after a few thousand seconds of measurement integration. The paper demonstrates an approach to initialize and engage the proposed laser stabilization system, starting from free-running laser and ending with the dual sensor frequency control system. The results show that the technique lowers the residual laser frequency noise in the LISA science band by over 3 orders of magnitude: from $30\mathrm{Hz}/\sqrt{\mathrm{Hz}}$ to as low as $7\mathrm{mHz}/\sqrt{\mathrm{Hz}}$, potentially allowing the requirements on Time Delay Interferometry (TDI) to be relaxed—possibly to the point where first-generation TDI may be sufficient.

The Sun provides an excellent target for studying spin-dependent dark matter-proton scattering due to its high matter density and abundant hydrogen content. Dark matter particles from the Galactic halo can elastically interact with Solar nuclei, resulting in their capture and thermalization in the Sun. The captured dark matter can annihilate into Standard Model particles including an observable flux of neutrinos. We present the results of a search for low-energy ($<500\mathrm{GeV}$) neutrinos correlated with the direction of the Sun using 7 years of IceCube data. This work utilizes, for the first time, new optimized cuts to extend IceCube’s sensitivity to dark matter mass down to 5 GeV. We find no significant detection of neutrinos from the Sun. Our observations exclude capture by spin-dependent dark matter-proton scattering with cross section down to a few times ${10}^{-41}{\mathrm{cm}}^2$, assuming there is equilibrium with annihilation into neutrinos/antineutrinos for dark matter masses between 5 GeV and 100 GeV. These are the strongest constraints at GeV energies for dark matter annihilation directly to neutrinos.

We construct the first comprehensive radioactive background model for a dark matter search with charge-coupled devices (CCDs). We leverage the well-characterized depth and energy resolution of the DAMIC at SNOLAB detector and a detailed geant4-based particle-transport simulation to model both bulk and surface backgrounds from natural radioactivity down to $50{\mathrm{eV}}_{\mathrm{ee}}$. We fit to the energy and depth distributions of the observed ionization events to differentiate and constrain possible background sources, for example, bulk ${}^3\mathrm{H}$ from silicon cosmogenic activation and surface ${}^{210}\mathrm{Pb}$ from radon plate-out. We observe the bulk background rate of the DAMIC at SNOLAB CCDs to be as low as $3.1\pm 0.6\mathrm{counts}{\mathrm{kg}}^{-1}{\mathrm{day}}^{-1}{\mathrm{keV}}_{\mathrm{ee}}^{-1}$, making it the most sensitive silicon dark matter detector. Finally, we discuss the properties of a statistically significant excess of events over the background model with energies below $200{\mathrm{eV}}_{\mathrm{ee}}$.