Only two types of Standard Model particles are able to propagate the 480meters separating the ATLAS interaction point and FASER: neutrinos and muons. Furthermore, muons are copiously produced in proton collisions. We propose to use $\mathrm{FASER}\nu$ as a muon fixed target experiment in order to search for new bosonic degrees of freedom coupled predominantly to muons. These muon force carriers are particularly interesting in light of the recent measurement of the muon anomalous magnetic moment. Using a novel analysis technique, we show that even in the current LHC run, $\mathrm{FASER}\nu$ could potentially probe previously unexplored parts of the parameter space. In the high-luminosity phase of the LHC, we find that the improved sensitivity of $\mathrm{FASER}\nu 2$ will probe unexplored parameter space and may be competitive with dedicated search proposals.

We numerically address the issue of which monopole operators are relevant under renormalization group flow in three-dimensional parity-invariant noncompact QED with four flavors of massless two-component Dirac fermion. Using lattice simulation and finite-size scaling analysis of the free energy to introduce monopole-antimonopole pairs in $N=4$ and $N=12$ flavor noncompact ${\mathrm{QED}}_3$, we estimate the infrared scaling dimensions of monopole operators that introduce $2\pi$ and $4\pi$ fluxes around them. We first show that the estimates for the monopole scaling dimensions are consistent with the large-$N$ expectations for $N=12$ ${\mathrm{QED}}_3$. Applying the same procedure in $N=4$ ${\mathrm{QED}}_3$, we estimate the scaling dimension of $4\pi$ flux monopole operator to be 3.7(3), which allows the possibility of the operator being irrelevant. This finding offers support to the scenario in which higher-flux monopoles are irrelevant deformations to the Dirac spin liquid phase that could be realized on certain non-bipartite lattices by forbidding $2\pi$-flux monopoles.

The phase diagram and the equation of state of quantum chromodynamics (QCD) is investigated in the presence of weak background electric fields by means of continuum extrapolated lattice simulations. The complex action problem at nonzero electric field is circumvented by a novel Taylor expansion, enabling the determination of the linear response of the thermal QCD medium to constant electric fields—in contrast to simulations at imaginary electric fields, which, as we demonstrate, involve an infrared singularity. Besides the electric susceptibility of QCD matter, we determine the dependence of the Polyakov loop on the field strength to leading order. Our results indicate a plasma-type behavior with a negative susceptibility at all temperatures, as well as an increase in the transition temperature as the electric field grows.

Based on the hadronic resonance picture, we explore a unified framework to describe the observed $Z_{cs}$ and $Z_c$ states that are close to the thresholds of the $D^{(*)}{\overline{D}}_s^{(*)}$ and $D^{(*)}{\overline{D}}^{(*)}$ systems, respectively. We assume that the $Z_{cs}(4000)$ and $Z_{cs}(3985)$ are two different states. Specifically, we assign the $Z_{cs}(4000)$ as the SU(3) partner of the $Z_c(3900)$ ($J^{PC}=1^{+-}$) due to its observation in the $J/\mathrm{\Psi }K$ channel, the difficulty of this assignment is the large width difference between the $Z_{cs}(4000)$ and the $Z_c(3900)$ state. Then the $Z_{cs}(3985)$ should corresponds to the $Z_c$ state that is close to the threshold of $D{\overline{D}}^{*}$ system with $J^{PC}=1^{++}$, the difficulty of this assignment is the absence of such a $Z_c$ state in experiment. We construct the effective potentials of the $Z_{cs}$ and $Z_c$ states by analogy with the effective potentials of the leading-order and next-to-leading-order $N-\overline{N}$ interactions. Then we introduce an SU(3) breaking factor $g_x$ to identify the differences between the effective potentials in the $Z_{cs}$ and $Z_c$ states. We perform two calculations to discuss the differences and similarities of the $Z_{cs}$ and $Z_c$ states. In the first calculation, we show that the above two difficulties can be explained simultaneously by the inclusion of the SU(3) breaking effect. In the second calculation, we show that this framework is promising to simultaneously describe the interactions of the observed $Z_{cs}$ and $Z_c$ states that are close to the thresholds of the $D^{(*)}{\overline{D}}_s^{(*)}$ and $D^{(*)}{\overline{D}}^{(*)}$ systems, respectively.

The possibility that gauge theories with chiral symmetry breaking below the conformal window exhibit an infrared fixed point is explored. With this assumption three aspects of pion physics are reproduced if the quark mass anomalous dimension at the infrared fixed point is ${\gamma }_{*}=1$. First, by matching the long-distance scalar adjoint correlation function. Second, by perturbing the fixed point by a small quark mass, the $m_q$-dependence of the pion mass is reproduced by renormalization group arguments. Third, consistency of the trace anomaly and the Feynman-Hellmann theorem, for small $m_q$, imply the same result once more. This suggests the following picture for the conformal window; close to its upper boundary ${\gamma }_{*}$ is zero and grows as the number of fermions is reduced until its lower boundary ${\gamma }_{*}=1$ is reached, where chiral symmetry breaking sets in. Below, the strongly coupled gauge theory with ${\gamma }_{*}=1$ is infrared dual to the free theory of pions. A possible dilaton sector of the scenario will be addressed in a companion paper.

A novel method to differentiate the effects of Dirac and Majorana (D-M) neutrinos in four-body decays has been discussed in [C. S. Kim et al., Inferring the nature of active neutrinos: Dirac or Majorana?, Phys. Rev. D 105, 113006 (2022).]. There, it is concluded that the back-to-back kinematic scenario seems to avoid the constraint imposed by the “practical Dirac-Majorana confusion theorem,” as one does not need to fully integrate over neutrino and antineutrino momenta. In this paper, we propose to analyze radiative leptonic lepton-decays ($\ell \to {\ell }^{\prime }\nu \overline{\nu }\gamma$), as an independent alternative process to study the possible Majorana nature of neutrinos. Our approach demonstrates that, in the back-to-back kinematic configuration (for the ${\ell }^{\prime }-\gamma$ and $\nu -\overline{\nu }$ systems, respectively), the distinction between Dirac and Majorana cases disappears when the inaccessible neutrino angle is integrated out, which might appear unexpected considering the claims in [C. S. Kim et al., Inferring the nature of active neutrinos: Dirac or Majorana?, Phys. Rev. D 105, 113006 (2022).]. Our results apply in absence of nonstandard interactions, which can enhance generally the sensitivity to the neutrino nature.

Holographic screens are codimension-one hypersurfaces that extend the notion of apparent horizons to general (non-black hole) spacetimes and that display interesting thermodynamic properties. We show that if a spacetime contains a codimension-two, boundary-homologous, minimal extremal spacelike surface $X$ (known as an HRT surface in $\mathrm{AdS}/\mathrm{CFT}$), then any holographic screens are sequestered to the causal wedges of $X$. That is, any single connected component of a holographic screen can be located in at most one of the causal future, causal past, inner wedge, or outer wedge of $X$. We comment on how this result informs possible coarse grained entropic interpretations of generic holographic screens, as well as on connections to semiclassical objects such as quantum extremal surfaces.

In this article, we set up a variational problem to arrive at the equation of the maximal hypersurface in the interior of a spherically symmetric evolving trapped region. In the first part of the article, we present the Lagrangian and the corresponding Euler-Lagrange equations that maximize the interior volume of a trapped region that is formed dynamically due to infalling matter in $D$-dimensions, with and without the cosmological constant. In the second part, we explore the properties of special radii, which we call Reinhart radii, that play a crucial role in approximating the maximal interior volume of a black hole. We derive a formula to locate these Reinhart radii in terms of coordinate invariants like area radius, principle values of the energy-momentum tensor, Misner-Sharp mass, and cosmological constant. Based on this formula, we estimate the location of Reinhart radii in various scenarios: (a) the case of static Bañados Teitelboim Zanelli black holes in ($2+1$) dimensions and for the Schwarzschild, Schwarzschild-de Sitter, and Schwarzschild-anti–de Sitter black holes in $D$-dimensions. We plot the location of the Reinhart radii in relation to the event horizon and cosmological horizon in a static $D$-dimensional scenario, (b) cosmological case: we prove that these Reinhart radii do not exist for homogeneous evolving dust for the zero and negative cosmological constant but exist in the presence of positive cosmological constant when the scale factor is greater than a critical value. We also show the relation between these Reinhart radii and Kodama vectors.

In this article, we consider a class of four-dimensional Einstein-Maxwell theory which is coupled nonminimally to a scalar field and the Gauss-Bonnet invariant. We mainly use the numerical methods to find the solutions to the theory, with the Newman, Tamburino, Unti (NUT) twist. We find explicitly the numerical solutions to all of the field equations. To find the appropriate consistent numerical solutions, we use the perturbative expansion of the fields asymptotically, as well as near horizon. The solutions describe the NUTty black holes with the scalar charge which also depend explicitly on the values of the nonminimal coupling constants. We provide a detailed numerical analysis of the solutions in terms of all existing parameters of the theory.

The stochastic gravitational wave background (SGWB) recently detected by the PTA collaborations could be the gravitational waves (GWs) induced by curvature perturbations. However, primordial black holes (PBHs) might be overproduced if the SGWB is explained by the GWs induced by the curvature perturbations that follow the Gaussian distribution. This motivates models associated with the non-Gaussianity of the curvature perturbations that suppress the PBH production rate. In this work, we show that the axion curvaton model can produce the curvature perturbations that induce GWs for the detected SGWB while preventing the PBH overproduction with the non-Gaussianity.

Recent advancements in gravitational wave astronomy have seen the application of convolutional neural networks (CNNs) in signal detection from compact binary coalescences. This study presents a comparative analysis of two CNN architectures: one-dimensional (1D) and two-dimensional (2D) along with an ensemble model combining both. We trained these models to detect gravitational wave signals from binary black hole (BBH) mergers, neutron star-black hole (NSBH) mergers, and binary neutron star (BNS) mergers within real detector noise. Our investigation entailed a comprehensive evaluation of the detection performance of each model type across different signal classes. To understand the models’ decision-making processes, we employed feature map visualization and attribution analysis. The findings revealed that while the 1D model showed superior performance in detecting BBH signals, the 2D model excelled in identifying NSBH and BNS signals. Notably, the ensemble model outperformed both individual models across all signal types, demonstrating enhanced detection capabilities. Additionally, input feature visualization indicated distinct areas of focus in the data for the 1D and 2D models, emphasizing the effectiveness of their combination.

A future Galactic supernova (SN) explosion can lead to a gamma-ray signal induced by ultralight axionlike particles (ALPs) thermally produced in the SN core and converted into high-energy photons in the Galactic magnetic field. The detection of such a signal is in the reach of the Large Area Telescope aboard the Fermi Gamma-Ray Space Telescope. The observation of gamma-ray emission from a future SN has a sensitivity to $g_{a\gamma }\gtrsim 4\times {10}^{-13}{\mathrm{GeV}}^{-1}$ for a SN at fiducial distance of 10 kpc and would allow us to reconstruct the ALP-photon coupling within a factor of $\sim 2$, mainly due to the uncertainties on the modeling of the Galactic magnetic field.

This paper investigates the impact of a lack of knowledge of instrumental noise on the characterization of stochastic gravitational wave backgrounds with the Laser Interferometer Space Antenna (LISA). We focus on constraints on modeled backgrounds that represent the possible backgrounds from the mergers of binary black holes of stellar origin, from primordial black hole generation, from nonstandard inflation, and from sound wave production during cosmic fluid phase transitions. We use splines to model generic, slowly varying, uncertainties in the auto- and cross-spectral densities of the LISA time delay interferometry channels. We find that allowing for noise knowledge uncertainty in this way leads to 1–2 orders of magnitude degradation in our ability to constrain stochastic backgrounds and a corresponding increase in the background energy density required for a confident detection. We also find that, to avoid this degradation, the LISA noise would have to be known at the subpercent level, which is unlikely to be achievable in practice.

The twist-3 contribution, consisting of twist-2 transversity generalized parton distributions (GPDs) and a twist-3 meson wave function, to deeply virtual pion electroproduction is discussed. The twist-3 meson wave function includes both the $q\overline{q}$ and the $q\overline{q}g$ Fock components. Two methods to regularize the end point singularities are introduced—quark transverse momenta and a gluon mass. Using existing generalized parton distribution parametrizations the transverse and the transverse-transverse interference cross sections for ${\pi }^0$ production are calculated and compared to experimental data.

We present the first observation of the singly Cabibbo-suppressed decay ${\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^0$ with a significance of $5.7\sigma$ and the first evidence of ${\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^{+}{\pi }^{-}$ decay with a significance of $3.1\sigma$, based on $e^{+}{e}^{-}$ annihilation data recorded by the BESIII detector at the BEPCII collider. The data correspond to an integrated luminosity of $6.4{\mathrm{fb}}^{-1}$, in the center-of-mass energy range from 4.600 to 4.950 GeV. We determine the branching fractions of ${\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^0$ and ${\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^{+}{\pi }^{-}$ relative to their Cabibbo-favored counterparts to be $\frac{\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^0)}{\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{\pi }^{+}{\pi }^0)}=(2.09\pm 0.39_{\mathrm{stat}}\pm 0.07_{\mathrm{syst}})\times {10}^{-2}$ and $\frac{\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^{+}{\pi }^{-})}{\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{\pi }^{+}{\pi }^{+}{\pi }^{-})}=(1.13\pm 0.41_{\mathrm{stat}}\pm 0.06_{\mathrm{syst}})\times {10}^{-2}$, respectively. Moreover, by combining our measured result with the world average of $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{\pi }^{+}{\pi }^0)$, we obtain the branching fraction $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{K}^{+}{\pi }^0)=(1.49\pm 0.27_{\mathrm{stat}}\pm 0.05_{\mathrm{syst}}\pm 0.08_{\mathrm{ref}})\times {10}^{-3}$. This result significantly departs from theoretical predictions based on quark $SU(3)$ flavor symmetry, which is underpinned by the presumption of meson pair $S$-wave amplitude dominance.

We investigate the ergoregion instability of area-quantized rotating quantum black holes (QBH) under gravitational perturbation. We show that the instability can be avoided in binary systems that include QBHs if the separation between the inspiraling components at the onset of black hole formation is less than a critical value. We also analyze the formation history of such systems from stellar progenitors and demonstrate that a significant fraction of progenitor masses cannot lead to QBH formation, making it unlikely for LIGO-Virgo black hole binaries to comprise rotating QBHs.

In this paper, we establish a unified parametrized framework for analyzing the polarization modes of gravitational waves in the general metric theory (where gravity is only described by the metric) and the general scalar-tensor theory (where gravity is described by the metric and an additional scalar field). Specifically, we study the polarization modes of gravitational waves in the most general metric theory and general scalar-tensor theory that satisfy the following conditions: (1) Spacetime is four-dimensional; (2) The theory satisfies the principle of least action; (3) The theory is generally covariant; (4) The action describing a free particle is $\int ds$. We find that the polarization modes of gravitational waves in the theory satisfying the above conditions depend on the selection of parameters in the framework, and the theory allows for up to all six polarization modes. Once we have established our framework, the analysis of the polarizations of gravitational waves in specific theories will depend on determining the corresponding parameters within our framework. We also find that the polarization modes of gravitational waves in the general metric theory and the general scalar-tensor theory that satisfy the conditions also have some interesting universal properties.

Inflationary and bouncing scenarios are two frameworks that provide the mechanism to overcome the horizon problem as well as generate the primordial perturbations. In this work, we investigate the conservation of perturbations in single-field models of both inflationary and bouncing scenarios, where the quantity, $z=a\mathrm{d}\varphi /\mathrm{d}\log a$, with $a$ representing the scale factor and $\varphi$ denoting the scalar field, decreases with time. We observe that this behavior occurs during the ultraslow-roll phase in the context of inflation and the contracting phase in the context of bounce. We show that the conjugate momentum associated with the comoving curvature perturbation during both the ultraslow-roll phase and the contracting phase of bouncing scenarios is conserved in the super-Hubble limit. We illustrate that, within the framework of inflation, this conservation of momentum allows for the evolution of perturbations across the ultraslow-roll phase, enabling the calculation of the power spectrum for modes that exit the Hubble radius before the ultraslow-roll phase begins. Similarly, in the context of a bounce, we can determine the power spectrum after the bounce using this method. We support our approach with both numerical and analytical arguments.

The IceCube Neutrino Observatory has recently reported strong evidence for neutrino emission from the Galactic plane. The signal is consistent with model predictions of diffuse emission from cosmic ray propagation in the interstellar medium. However, owing to IceCube’s limited potential of identifying individual neutrino sources, it is also feasible that unresolved Galactic sources could contribute to the signal. We investigate the contribution of this quasidiffuse emission and show that the observed Galactic diffuse flux at 100 TeV could be dominated by the hard emission of unresolved sources. Particularly interesting candidate sources are young massive stellar clusters that have been considered as cosmic-ray PeVatrons. We examine whether this hypothesis can be tested by the upcoming KM3NeT detector or the planned future facility IceCube-Gen2 with about 5 times the sensitivity of IceCube.

Recent studies on cosmic rays (CRs) have reported the possibility of an excess in the antiproton flux around 10–20 GeV. However, the associated systematic uncertainties have impeded the interpretation of these findings. In this study, we conduct a global Bayesian analysis to constrain the propagation parameters and evaluate the CR antiproton spectrum, while comprehensively accounting for uncertainties associated with interstellar CR propagation, production cross sections for antiprotons and other secondaries, and the charge- and energy-dependent effects of solar modulation. We establish that the most recent Alpha Magnetic Spectrometer (AMS-02) $\overline{p}$ spectrum is in agreement with a pure secondary origin. Based on this, we establish upper limits on dark matter (DM) annihilation. We also determine that the AMS-02 data favor the empirical hadronic interaction models over phenomenological ones. Finally, we find that the latest AMS-02 antiproton data from 2011 to 2018 disfavors the antiproton excess at $\mathcal{O}(10)\mathrm{GeV}$ and the corresponding DM interpretation that can simultaneously account for the Galactic Center excess in the gamma-ray observation.