The Moon blocks cosmic rays, causing a deficit in their flux from its direction. Characterizing this Moon shadow is a technique used by cosmic ray air shower experiments to calibrate their angular resolution and validate the pointing accuracy. The GRAPES-3 air shower array, located in Ooty, India consists of an array of scintillator detectors and a large area muon telescope. It is sensitive to the measurement of cosmic ray and gamma ray induced showers in the TeV-PeV energy range. The timing measurements of the scintillator detectors were improved after upgrading the time-to-digital converters and coaxial cables in late 2012. The propagation delay of photomultiplier signal in coaxial cables were accurately determined on hourly basis using a random walk technique. The correction of shower front curvature for its dependence on the shower size and age together with accurate timing measurements led to a better angular resolution estimated using array division methods reported elsewhere [Jhansi et al., J. Cosmol. Astropart. Phys. 07 (2020) 024]. In this paper, we discuss the validation of the angular resolution by observing the shadow of the Moon in cosmic ray flux using 3 years (2014 to 2016) of air shower data recorded during the postupgrade period. The angular resolution of the array was estimated to be $0.83°\pm 0.09°$ with a statistical significance of $9.1\sigma$ and pointing accuracy along the right ascension and declination directions were obtained to be $0.032°\pm 0.004°$ and $0.09°\pm 0.003°$ for showers of energy $>5\mathrm{TeV}$, containing about 95% of triggered showers. The angular resolution improves to $0.38°\pm 0.06°$ and $0.29°\pm 0.06°$ for energy $>100\mathrm{TeV}$ and $>200\mathrm{TeV}$ respectively. The results are consistent with the values obtained from array division methods and are comparable to several air shower arrays that are located at almost twice the altitude of GRAPES-3. The improved angular resolution together with the accurate pointing increases the ability of GRAPES-3 to detect multi-TeV gamma ray sources.

The framework of the so-called 3-3-1LHN model accommodates two different, but viable, scenarios of dark matter. In one case, the dark matter particle is a heavy Dirac neutrino $N_1$. In the other case, we have a scalar, $\varphi$, as a dark matter candidate. In both cases, the dark matter phenomenology, relic abundance, and scattering cross section off of nuclei are controlled by exchange of $Z^{\prime }$. We then investigate the impact on the parameter space $(M_{Z^{\prime }},M_{(N_1,\varphi )})$ due to the recent PandaX-4T experimental result in both scenarios. We obtain that the PandaX-4T experiment excludes scenarios with dark matter mass below 1.9 TeV. Concerning $Z^{\prime }$, we find the lower bound $M_{Z^{\prime }}>4.1\mathrm{TeV}$ for the case where $N_1$ is the dark matter and $M_{Z^{\prime }}>5.7\mathrm{TeV}$ for the other case. This implies that the 3-3-1 symmetry is spontaneously broken above 10 TeV scale. We also comment on the contributions to the relic abundance of processes involving flavor-changing neutral current mediated by $Z^{\prime }$.

We show that models in which the strong $CP$ problem is solved by introducing an axion field with a mass enhanced by non-QCD UV dynamics at a scale ${\mathrm{\Lambda }}_{\mathrm{SI}}$ exhibit enhanced sensitivity to external sources of $CP$ violation. In the presence of higher-dimensional $CP$-odd sources at a scale ${\mathrm{\Lambda }}_{\mathrm{CP}}$, the same mechanisms that enhance the axion mass also modify the axion potential, shifting the potential minimum by a factor $\propto {\mathrm{\Lambda }}_{\mathrm{SI}}^2/{\mathrm{\Lambda }}_{\mathrm{CP}}^2$. This phenomenon of $CP$-violation enhancement, which puts stringent constraints on the scale of new physics, is explicitly demonstrated within a broad class of “small instanton” models with $CP$-odd sources arising from the dimension-six Weinberg gluonic and four-fermion operators. We find that for heavy axion masses $\gtrsim 100\mathrm{MeV}$, arising from new dynamics at ${\mathrm{\Lambda }}_{\mathrm{SI}}\lesssim {10}^{10}\mathrm{GeV}$, $CP$ violation generated up to the Planck scale can be probed by future electric dipole moment experiments.

If non-Abelian gauge fields in $SU(3)$ QCD have a line-singularity leading to noncommutativity with respect to successive partial-derivative operations, the non-Abelian Bianchi identity is violated. The violation as an operator is shown to be equivalent to violation of Abelian-like Bianchi identities. Then there appear eight Abelian-like conserved magnetic monopole currents of the Dirac type in $SU(3)$ QCD. Exact Abelian (but kinematical) symmetries appear in non-Abelian $SU(3)$ QCD. Here we try to show, using lattice Monte Carlo simulations of $SU(3)$ QCD, the Abelian dual Meissner effect due to the above Abelian-like monopoles are responsible for color confinement in $SU(3)$ QCD. If this picture is correct, the string tension of non-Abelian Wilson loops is reproduced fully by that of the Abelian Wilson loops. This is called perfect Abelian dominance. Furthermore, since the linear potential in Abelian Wilson loops is caused by the solenoidal monopole currents, the Abelian string tension is fully reproduced by that of Abelian monopole potentials. It is called perfect monopole dominance. In this report, the perfect Abelian dominance is shown to exist with the help of the multilevel method but without introducing additional smoothing techniques like partial gauge fixings, although lattice sizes studied are not large enough to study the infinite volume limit. Perfect monopole dominance on ${24}^3\times 4$ at $\beta =5.6$ is also shown without any additional gauge fixing but with a million thermalized configurations. The dual Meissner effect around a pair of static quark and antiquark is studied also on the same lattice. Abelian electric fields are squeezed due to solenoidal monopole currents and the penetration length for an Abelian electric field of a single color is the same as that of non-Abelian electric field. The coherence length is also measured directly through the correlation of the monopole density and the Polyakov loop pair. The Ginzburg-Landau parameter indicates that the vacuum type is the weak type I (dual) superconductor. Although the scaling and the infinite-volume limits are not studied yet, the results obtained above without any additional assumptions as well as more clear previous $SU(2)$ results seem to suggest strongly the above Abelian dual Meissner picture of color confinement mechanism.

Recent results suggest that flow-based algorithms may provide efficient sampling of field distributions for lattice field theory applications, such as studies of quantum chromodynamics and the Schwinger model. In this work, we provide a numerical demonstration of robust flow-based sampling in the Schwinger model at the critical value of the fermion mass. In contrast, at the same parameters, conventional methods fail to sample all parts of configuration space, leading to severely underestimated uncertainties.

Semi-inclusive $J/\psi$ production in electron-proton collisions is a promising process to study gluon transverse momentum distributions (TMDs) at the future electron-ion collider (EIC). In this article, we improve on previous studies of the $\cos 2\varphi$ azimuthal asymmetry that arises from the linear polarization of gluons inside unpolarized protons by including TMD evolution. We find that in the TMD regime the asymmetry grows monotonically with increasing transverse momentum of the outgoing $J/\psi$, in contrast to tree level calculations with Gaussian TMDs. Our predictions for the asymmetry at the EIC can become very large at larger $x$, $Q$, and transverse momenta, even larger than the positivity bound. This problem stems from the very small $b$ region and implies a range of validity of TMD factorization that is more restricted than usually expected. We also include an estimate of the nonperturbative uncertainty from the large $b$ region and we conclude that it is smaller than the largest source of uncertainty, which stems from the choice of color octet long-distance matrix elements.

We reanalyze the anomalous angular distribution of lepton pairs produced in a pion-induced Drell-Yan process by taking into account the Glauber gluon effect in the $k_T$ factorization theorem. Compared to the previous study, we adopt the realistic parton distribution functions (PDFs) for a proton from the Coordinated Theoretical-Experimental Project on QCD and for a pion from the xFitter, include the QCD evolutions of the strong coupling and the PDFs, and integrate the differential cross section over the kinematic regions for the NA10, E615 and COMPASS experiments. These improvements then allow rigorous confrontations of theoretical results with the data. It is shown that the lepton angular distribution and the violation of the Lam-Tung relation measured in all the above experiments can be well accommodated with a single Glauber phase. We illustrate the Glauber effect in the geometric picture for a Drell-Yan process, and its distinction from the conventional Boer-Mulders mechanism. The observables are pointed out, which can be used to discriminate the two proposals, when data become more precise.

An interpretation is given for elastic proton scattering at ultrahigh energies with impact-parameter amplitude exceeding the black disk limit. It is shown that this scattering mode can arise due to the contribution of an exceptional intermediate state that unites correlated partons of colliding protons at ultrahigh energies into a single coherent system. The behavior of the real part of the amplitude in this mode is discussed.

Analog gravity describes fluctuations of hydrodynamic systems in terms of a massless scalar field propagating on curved spacetimes. This analogy between hydrodynamic and gravitational systems remains largely unexplored for nonlinear dynamical effects. In this paper, we provide the first description of dynamical analog spacetimes up to arbitrary order nonlinear perturbations constructed about stationary solutions. We find a high frequency response that exhibit known properties of perturbed black holes, as well as a low frequency regime for analog spacetimes with novel characteristics. Our framework more generally describes nonlinear perturbations of compressible hydrodynamic systems as analogs of nonlinear wave phenomena on black hole spacetimes.

We calculate the complete differential decay distributions for the $B$ meson decays, $\overline{B}\to D^{(*)}\ell \overline{X}$, to a massive right-handed (RH) neutrino in the low-energy effective field theory (LEFT) framework. We find that a massive RH neutrino does not introduce any new angular structures compared to the massless case, but can cause significant distortions in angular observables. We study the phenomenology of low-energy four-fermion operators permitted by the standard model effective field theory (SMEFT) extended with RH neutrinos (SMNEFT). We show that to explain the positive value of the difference in forward-backward asymmetries, $\mathrm{\Delta }{A}_{\mathrm{FB}}\equiv A_{\mathrm{FB}}^{\mu }-A_{\mathrm{FB}}^e$, tentatively inferred from Belle data, the RH neutrino must be massive. We also make predictions for $q^2$ dependent angular observables to motivate future measurements.

The double copy of the Coulomb solution in three dimensions is a nonvacuum solution that can be obtained through different matter couplings. It is the static black hole solution of Einstein-Maxwell theory or general relativity minimally coupled to a free scalar field (with one ghost sign in the action in both cases). We consider generalizations of these matter couplings by paying particular attention to the regularity of the static black solution on the gravity side and the corresponding single copy electric field in the gauge theory. We show that (i) Einstein-Born-Infeld theory yields a singular double copy, which admits stable orbits for certain choices of parameters, with a regular single copy electric field, and (ii) black hole solutions constructed by Bueno et al. [Phys. Rev. D 104, L021501 (2021).] by coupling to the scalar field exemplify mostly regular double copies with regular single copy electric fields and also admit stable orbits. Additionally, we use these solutions to investigate the connection between horizons on the gravity side and electric fields on the gauge theory side, which was previously observed in four dimensions.

In this work we present a “modest” holographic reconstruction of the bulk geometry in asymptotically flat spacetime using the two-point correlators of boundary quantum field theory (QFT) in asymptotically flat spacetime. The boundary QFT lives on the null boundary of the spacetime, namely null infinity and/or the Killing horizons. The bulk reconstruction relies on two unrelated results: (i) there is a bulk-to-boundary type correspondence between free quantum fields living in the bulk manifold and free quantum fields living on its null boundary, and (ii) one can construct the metric by making use of the Hadamard expansion of the field living in the bulk. This holographic reconstruction is “modest” in that the fields used are noninteracting and not strong-weak holographic duality in the sense of AdS/CFT, but it works for generic asymptotically flat spacetime subject to some reasonably mild conditions.

Analog gravity models describe linear fluctuations of fluids as a massless scalar field propagating on stationary acoustic spacetimes constructed from the background flow. In this paper, we establish that this paradigm generalizes to arbitrary order nonlinear perturbations propagating on dynamical analog spacetimes. Our results hold for all inviscid, spherically symmetric and barotropic nonrelativistic flows in the presence of an external conservative force. We demonstrate that such fluids always admit a dynamical description governed by a coupled pair of wave and continuity equations. We provide an iterative approach to solve these equations about any known stationary solution to all orders in perturbation. In the process, we show that there exists a dynamical acoustic spacetime on which nonlinear fluctuations of the mass accretion rate propagate. The dynamical acoustic spacetime has a well-defined causal structure and curvature, and we find a classical fluctuation relation for the horizon. We find that the spacetime can have acoustic horizons that grow as well as recede under perturbations, with the latter having no known black hole analog. As an example, we numerically investigate the Bondi flow solution subject to exponentially damped time dependent perturbations. We find that second and higher order classical perturbations possess an acoustic horizon that oscillates to a new size at late times. In particular, the case of a receding acoustic horizon is realized through “low frequency” perturbations. We discuss our results in the context of more general analog models and its potential implications on astrophysical accretion flows.

We disclose the effects of an extra longitudinal degree of freedom on the evolution of perturbations in the framework of mimetic gravity. We consider a flat Friedmann-Robertson-Walker background and explore the linear perturbations by adopting the spherically symmetric collapse formalism. By suitably choosing the potential of the mimetic field, we are able to solve the perturbed field equations in the linear regime and derive the matter density contrast ${\delta }_m$ in terms of the redshift parameter $z$. We observe that ${\delta }_m$ starts growing at the early stages and, as the Universe expands, it grows faster compared to the standard cosmology. This may due to the extra degree of freedom of the gravitational field which affects the growth of perturbations. We observe that in the presence of a mimetic potential, the growth rate function is smaller than the $\mathrm{\Lambda }\mathrm{CDM}$ model in small redshifts. We then consider the effects of this potential on the density abundance, the deceleration parameter and jerk parameter. We find out that mimetic potential can play the role of dark energy (DE) and affects the dynamics of matter perturbations and cosmological parameters. We also investigate the mass function and the number count for the collapsed objects in the mimetic scenario. We find that the mass function of models with potential is smaller than the model without potential. With the decreasing the role of DE, the mass function starts to grow in smaller redshifts; i.e., halo abundance is formed later. It is found that the more massive structures are less abundant and form at later times, as it should be in the hierarchical model of structure formation.

We consider the effects of the Earth’s rotation on antenna patterns of a ground-based gravitational wave (GW) detector in a general metric theory that allows at most six polarization states (two spin-0, two spin-1, and two spin-2) in a four-dimensional spacetime. By defining the cyclically averaged antenna matrix for continuous GWs from a known pulsar, we show that waveforms for each polarization state can be uniquely reconstructed in a time domain from a given set of the strain outputs at a single detector. Constraining the propagation speed of extra polarization modes, if they coexist with the transverse-traceless modes, is also discussed. We also examine possible effects due to the length-of-day modulation as well as a secular change in the pulsar spin period.

In this work we consider a generalized Bronnikov-Ellis wormhole and the tideless Morris-Thorne wormhole and we study the propagation of massive scalar fields. We calculate the quasinormal frequencies using the Wentzel-Kramers-Brillouin method and the pseudospectral Chebyshev method and we show the presence of an anomalous decay rate for the quasinormal modes in the generalized Bronnikov-Ellis wormhole. However, such anomalous behavior is avoided for the fundamental mode in the Morris-Thorne wormhole background.

In this manuscript we reassess the potential of interacting dark matter–dark energy models in solving the Hubble constant tension. These models have been proposed but also questioned as possible solutions to the $H_0$ problem. Here we examine several interacting scenarios against cosmological observations, focusing on the important role played by the calibration of supernovae data. In order to reassess the ability of interacting dark matter–dark energy scenarios in easing the Hubble constant tension, we systematically confront their theoretical predictions using a prior on the supernovae Ia absolute magnitude $M_B$, which has been argued to be more robust and certainly less controversial than using a prior on the Hubble constant $H_0$. While some data combinations do not show any preference for interacting dark sectors and in some of these scenarios the clustering ${\sigma }_8$ tension worsens, interacting cosmologies with a dark energy equation of state $w<-1$ are preferred over the canonical $\mathrm{\Lambda }\mathrm{CDM}$ picture even with cosmic microwave background data alone and also provide values of ${\sigma }_8$ in perfect agreement with those from weak lensing surveys. Future cosmological surveys will test these exotic dark energy cosmologies by accurately measuring the dark energy equation of state and its putative redshift evolution.

We study the properties of pasta structures and their influence on the neutron star observables employing the effective relativistic mean-field (E-RMF) model. The compressible liquid drop model is used to incorporate the finite size effects, considering the possibility of nonspherical structures in the inner crust. The unified equation of state are constructed for several E-RMF parameters to study various properties such as pasta mass and thickness in the neutron star’s crust. The majority of the pasta properties are sensitive to the symmetry energy in the subsaturation density region. Using the results from Monte Carlo simulations, we estimate the shear modulus of the crust in context of quasiperiodic oscillations from soft gamma-ray repeaters and calculate the frequency of fundamental torsional oscillation mode in the inner crust. Global properties of the neutron star such as mass-radius profile, the moment of inertia, crustal mass, crustal thickness and fractional crustal moment of inertia are worked out. The results are consistent with various observational and theoretical constraints.

The pion structure in Minkowski space is explored using the Nakanishi integral representation. A general framework is developed for the pion Bethe-Salpeter amplitude based on the Källen-Lehmann representation of the dressed quarks with an ansatz for the pseudoscalar $\pi -q\overline{q}$ vertex fulfilling the axial Ward-Takahashi identity. The Nakanishi weight functions are derived for the scalar amplitudes associated with the decomposition of the pion Bethe-Salpeter amplitude in different operator bases in the Dirac spinor space in terms of the involved spectral densities. The approach is applied to an analytical model of the pion Bethe-Salpeter amplitude, which is combined with Landau gauge lattice QCD results for the quark running mass at spacelike momentum. From the Nakanishi integral representation several pion observables were calculated, such as the decay constant, the spin decomposition of the valence probabilities, longitudinal and transverse momentum distributions from the valence component of the light-front wave function.