We discuss a model based on the dark sector described by a non-Abelian $SU(2{)}_D$ gauge symmetry where we introduce $SU(2{)}_L\times SU(2{)}_D$ bidoublet vector-like leptons to generate active neutrino masses and kinetic mixing between $SU(2{)}_D$ and $U(1{)}_Y$ gauge fields at the one-loop level. After spontaneous symmetry breaking of $SU(2{)}_D$, we have a remnant $Z_4$ symmetry, guaranteeing the stability of dark matter candidates. We formulate the neutrino mass matrix and related lepton-flavor-violating processes and discuss dark matter physics where we estimate relic density of dark matter. We find that our model realizes a multicomponent dark matter scenario due to the $Z_4$ symmetry, and that the relic density can be explained by gauge interactions with a kinetic mixing effect.

The cross section for lepton pair annihilation into a photon and a dark photon or an axionlike particle is constant for large center-of-mass energies because some of the portal operators coupling the Standard Model and dark sector are proportional to the energy. Feebly coupled though they are, these portal operators will be enhanced by the large center-of-mass energy made available by a muon collider and thus provide the ideal example of possible physics beyond the Standard Model to be studied with such a machine. We discuss the characteristic signature of the presence of these operators: monochromatic single photon events for the two benchmarks of having center-of-mass energies of 3 and 10 TeV and integrated luminosity of, respectively, 1 and $10{\mathrm{ab}}^{-1}$. We find that an effective scale of the portal operator as large as $\mathrm{\Lambda }=112\mathrm{TeV}$ for an axionlike particle and $\mathrm{\Lambda }=141\mathrm{TeV}$ for a dark photon can be separated from the background with a confidence level of 95% in the first benchmark; these interaction scales can be raised to $\mathrm{\Lambda }=375$ and 459 TeV in the case of the second benchmark. The signal for the pseudoscalar particle can be distinguished from that of the spin-1 with about 500 events. The response of the detector to high-energy photons is examined.

The E989 experiment at the Fermi National Laboratory reported a $4.2\sigma$ discrepancy between the measured magnetic dipole moment of the muon, and its prediction in the Standard Model (SM). In this study, we address the anomaly by considering a minimal and generic extension to the SM which also provides for a dark matter (DM) candidate. The extra states in this framework are: a SM singlet Majorana fermion, referred to as the Bino, playing the role of DM; and muonic scalars, referred to as sleptons. The couplings between the sleptons, SM muons and the Bino can account for the muon $g-2$ anomaly if the scalar muon partners, or smuons, mix chirality. On the other hand, the DM relic density is satisfied primarily through coannihilation effects involving the Bino and the lighter sleptons. The viable parameter space of our model includes regions with relatively light coannihilating particles, similar to what has been found in previous scans of the Minimal Supersymmetric Standard Model (MSSM). Relaxing the assumption of minimal flavor violation typically assumed in the MSSM, we see that scenarios with sizable smuon mixing and large mass splittings between the smuons can satisfy both the muon $g-2$ anomaly and the DM relic density for coannihilating particle masses up to and beyond the TeV scale. When we specify the origin of the left-right smuon mixing to be trilinear couplings between the smuons and the SM Higgs boson, the constraints on these scenarios arising from perturbative unitarity and electroweak vacuum stability confine the coannihilating particle masses to be $\lesssim 1\mathrm{TeV}$. We demonstrate that next generation direct detection experiments are only marginally sensitive to the viable parameter space of our model, and, thus, a future lepton collider could be the essential probe necessary to distinguish our model from other solutions to the muon $g-2$ anomaly which involve extra states beyond the SM.

We consider the production of matter and radiation during reheating after inflation, restricting our attention solely to gravitational interactions. Processes considered are the exchange of a graviton, $h_{\mu \nu }$, involved in the scattering of the inflaton or particles in the newly created radiation bath. In particular, we consider the gravitational production of dark matter (scalar or fermionic) from the thermal bath as well as from scattering of the inflaton condensate. We also consider the gravitational production of radiation from inflaton scattering. In the latter case, we also derive a lower bound on the maximal temperature of order of ${10}^{12}\mathrm{GeV}$ for a typical $\alpha$-attractor scenario from $\varphi \varphi \to h_{\mu \nu }\to$ Standard Model fields (dominated by the production of Higgs bosons). This lower gravitational bound becomes the effective maximal temperature for reheating temperatures, $T_{\mathrm{RH}}\lesssim {10}^9\mathrm{GeV}$. The processes we consider are all minimal in the sense that they are present in any nonminimal extension of the Standard Model theory based on Einstein gravity and cannot be neglected. We compare each of these processes to determine their relative importance in the production of both radiation and dark matter.

The calculation of dynamic response functions is expected to be an early application benefiting from rapidly developing quantum hardware resources. The ability to calculate real-time quantities of strongly correlated quantum systems is one of the most exciting applications that can easily reach beyond the capabilities of traditional classical hardware. Response functions of fermionic systems at moderate momenta and energies corresponding roughly to the Fermi energy of the system are a potential early application because the relevant operators are nearly local, and the energies can be resolved in moderately short real time, reducing the spatial resolution and gate depth required. This is particularly the case in quasielastic electron and neutrino scattering from nuclei, a topic of great interest in the nuclear and particle physics communities and directly related to experiments designed to probe neutrino properties. In this work we use current quantum hardware and error mitigation protocols to calculate response functions for a highly simplified nuclear model through calculations of a 2-point real time correlation function for a modified Fermi-Hubbard model in two dimensions with three distinguishable nucleons on four lattice sites.

We consider $1+1$ dimensional Yang-Mills theory with gauge group $G$ coupled to a massive Majorana fermion field in an adjoint representation and a number of massless Dirac or Majorana fermions transforming in arbitrary representations of the gauge group $G$. It is shown that the spectrum of the massive sector of this theory becomes supersymmetric at particular mass of adjoint fermion. This mass is independent of the detailed structure of the massless sector of the model and depends only on the gauge group $G$ and integer $k$ measuring the total anomaly. The massless sector of the model is shown to be not necessarily supersymmetric.

The resummed thermodynamics of $\mathcal{N}=4$ supersymmetric Yang-Mills theory in four space-time dimensions has been calculated previously to two loop order within hard thermal loop perturbation theory (HTLpt) using the canonical dimensional regularization (DRG) scheme. Herein, we revisit this calculation using the regularization by dimensional reduction (RDR) scheme. Since the RDR scheme manifestly preserves supersymmetry it is the preferred scheme; however, it is important to assess if and by how much the resummed perturbative results depend on the regularization scheme used. Comparing predictions for the scaled entropy obtained using the DRG and RDR schemes we find that for $\lambda \lesssim 6$ they are numerically very similar. We then compare the results obtained in both schemes with the strict perturbative result, which is accurate up to order ${\lambda }^2$, and a generalized Padé approximant constructed from the known large-$N_c$ weak- and strong-coupling expansions. Comparing the strict perturbative expansion of the two-loop HTLpt result with the perturbative expansion to order ${\lambda }^2$, we find that both the DRG and RDR HTLpt calculations result in the same scheme-independent predictions for the coefficients at order $\lambda$, ${\lambda }^{3/2}$, and ${\lambda }^2\log \lambda$; however, at order ${\lambda }^2$ there is a residual regularization scheme dependence.

The doubly charmed baryon ${\mathrm{\Xi }}_{cc}^{++}$ was observed by LHCb Collaboration in 2017. The branching fractions of two-body doubly charmed baryon decays were predicted in the framework of a rescattering mechanism, and some $SU(3{)}_F$ relations were investigated in the topological amplitudes. In this work, we study the correlation between a topological diagram at quark level and a rescattering triangle diagram at hadron level in the doubly charmed baryon decay. The completeness of our framework is confirmed from the fact that all 12 possible structures of meson-baryon scattering appear once each in the intermediate form between the topological diagram and the triangle diagram, topological-scattering diagram. It is found that the triangle diagrams derived from the topological diagrams are consistent with the ones derived directly from the chiral Lagrangian. The relative magnitudes of rescattering contributions in the $C$, $C^{\prime }$, $E$, $E^{\prime }$, $P$, and $P^{\prime }$ diagrams extracted from $SU(3{)}_F$ symmetry are consistent with the numerical analysis in literature. Taking ${\mathrm{\Xi }}_{cc}^{++}\to {\mathrm{\Xi }}_c^{+}{\pi }^{+}$, ${\mathrm{\Xi }}_{cc}^{+}\to {\mathrm{\Xi }}_c^0{\pi }^{+}$, and ${\mathrm{\Xi }}_{cc}^{+}\to {\mathrm{\Xi }}_c^{+}{\pi }^0$ modes as examples, we show the isospin relation is satisfied in terms of triangle diagrams.

We study the $CP$ violation in the lepton-number-violating process $B_s^0\to D_s^{-}{\mu }^{+}{\mu }^{+}{\pi }^{-}$ and its $CP$-conjugate process $\overline{B_s^0}\to D_s^{+}{\mu }^{-}{\mu }^{-}{\pi }^{+}$ that are induced by two GeV-scale Majorana neutrinos with nearly-degenerate masses. Our result shows that the size of the $CP$ violation could become considerable if the mass difference between the two Majorana neutrinos is around the decay width of the neutrinos. We perform experimental analysis on the $CP$-violating processes at LHCb within its upgrade II. The analysis shows that under current constraint on the heavy-light neutrino mixing parameter, it is possible that such $CP$ violation is observed with the LHCb experimental ability. We also give the upper bound on the heavy-light mixing parameter $|U_{\mu N}{|}^2$ under the assumption that no positive signal of the process is observed. The result shows that such modes can give complementary constraint compared with previous experiments such as NuTeV, BEBC, etc., in the mass region $1\mathrm{GeV}<m_N<3\mathrm{GeV}$.

We analyze families of hybrid equations of state of cold QCD matter, which combine input from gauge-gravity duality and from various ab initio methods for nuclear matter at low density, and predict that all neutron stars are fully hadronic without quark matter cores. We focus on constraints from recent measurements by the NICER telescope on the radius and mass of the millisecond pulsar PSR $\mathrm{J}0740+6620$. These results are found to be consistent with our approach: they set only mild constraints on the hybrid equations of state and favor the most natural models which are relatively stiff at low density. Adding an upper bound on the maximal mass of neutron stars, as suggested by the analysis of the GW170817 neutron star merger event, tightens the constraints considerably. We discuss updated predictions on observables such as the transition density and latent heat of the nuclear to quark matter transition as well as the masses, radii, and tidal deformabilities of neutron stars.

We present an exact solution of the Maxwell-Einstein equations, which describes the exterior of a charged spherical mass collapsing into its own trapping horizon and then bouncing back from an antitrapping horizon at the same space location of the same asymptotic region. The solution is locally but not globally isometric to the maximally extended Reissner-Nordström metric and depends on seven parameters. It is regular and defined everywhere except for a small region, where quantum tunneling is expected. This region lies outside the mass: The mass bounce and its near exterior are governed by classical general relativity. We discuss the relevance of this result for the fate of realistic black holes. We comment on the possible effects of the classical instabilities and the Hawking radiation.

Nodal, excited compactons in the $\mathbb{C}{P}^N$ models with V-shaped potentials are analyzed. It is shown that the solutions exist as compact $Q$-balls and $Q$-shells. The solutions have a discontinuity in the second derivative associated with the character of the potential, however, their energy and charge densities are both continuous. The excited $Q$-balls and $Q$-shells are analyzed as electrically neutral and electrically charged objects.

We consider entanglement across a planar boundary in flat space. Entanglement entropy is usually thought of as the von Neumann entropy of a reduced density matrix, but it can also be thought of as half the von Neumann entropy of a product of reduced density matrices on the left and right. The latter form allows a natural regulator in which two cones are smoothed into a Euclidean hourglass geometry. Since there is no need to tensor factor the Hilbert space, the regulated entropy is manifestly gauge invariant and has a manifest state-counting interpretation. We explore this prescription for scalar fields, where the entropy is insensitive to a nonminimal coupling, and for Maxwell fields, which have the same entropy as $d-2$ scalars.

We study the circular motion of charged particles near a charged black hole. The general form of the Lyapunov exponent of charged particles is obtained by using the Jacobian matrix. The results show that the chaos bound can be saturated by the circular motion of charged particles on the horizon. By further expanding the Lyapunov exponent near the horizon and investigating Reissner-Nordström (RN) black holes with different $M/Q$, we find that in contrast to the static equilibrium, the circular motion of charged particles can have a larger Lyapunov exponent due to the existence of angular momentum. For the RN black holes which have the mass-charge ratio $1<M/Q<1.1547$, the chaos bound is locally violated by the null and the timelike circular motion with large angular momentum. As an illustration of the universality of our results, we study the charged particles’ circular motion near the Reissner-Nordström Anti–de Sitter (RN-AdS) black hole and find that the null and the timelike circular motion with large angular momentum can exceed the chaos bound under the background of RN-AdS black holes with the mass-charge ratio in the range $1.23132<M/Q<1.75225$.

We use big bang nucleosynthesis (BBN) data in order to impose constraints on higher-order modified gravity and, in particular, on (i) $f(G)$ Gauss-Bonnet gravity and $f(P)$ cubic gravities arising, respectively, through the use of the quadratic-curvature Gauss-Bonnet $G$ term and the cubic-curvature combination, (ii) string-inspired quadratic Gauss-Bonnet gravity coupled to the dilaton field, (iii) models with string-inspired quartic curvature corrections, and (iv) running vacuum models. We perform a detailed investigation of the BBN epoch, and we calculate the deviations of the freeze-out temperature $T_f$ in comparison to the $\mathrm{\Lambda }\mathrm{CDM}$ paradigm. We then use the observational bound on $|\frac{\delta T_f}{T_f}|$ in order to extract constraints on the involved parameters of various models. We find that all models can satisfy the BBN constraints, and thus, they constitute viable cosmological scenarios, since they can additionally account for the dark energy sector and the late-time acceleration, in a quantitative manner, without spoiling the formation of light elements during the BBN epoch. Nevertheless, the obtained constraints on the relevant model parameters are quite strong.

In this work, we study the existence of asymptotically Lifshitz black holes in critical gravity in four dimensions with a negative cosmological constant under two scenarios: First, including dilatonic fields as the matter source, where we find an asymptotically Lifshitz solution for a fixed value of the dynamical exponent $z=4$. As a second case, we also added a nonminimally coupled scalar field $\mathrm{\Phi }$ with a potential given by a mass term and a quartic term. Using this approach, we found a solution for $z$ defined in the interval (1,4), recovering the Schwarzchild-anti–de Sitter case with planar base manifold in the isotropic limit. Moreover, when we analyzed the limiting case $z=4$, we found that there exists an additional solution that can be interpreted as a stealth configuration in which the stealth field is overflying the $z=4$ solution without the nonminimally coupled field $\mathrm{\Phi }$. Finally, we studied the nontrivial thermodynamics of these new anisotropic solutions and found that they all satisfy the first law of thermodynamics as well as the Smarr relation. We were also able to determine that the nonstealth configuration is thermodynamically preferred in this case.

We carefully perform a Hamiltonian Dirac’s constraint analysis of the $\omega =-\frac{3}{2}$ Brans-Dicke theory with the Gibbons-Hawking-York boundary term. The Poisson brackets are computed via functional derivatives. After a brief summary of the results for the $\omega \ne -\frac{3}{2}$ case [G. Gionti S. J., Canonical analysis of Brans-Dicke theory addresses Hamiltonian inequivalence between the Jordan and Einstein frames, Phys. Rev. D 103, 024022 (2021)] we derive all Hamiltonian Dirac’s constraints and constraint algebra in both the Jordan and the Einstein frames. Confronting and contrasting Dirac’s constraint algebra in both frames, it is shown that they are not equivalent. This highlights that the transformations from the Jordan to the Einstein frames are not Hamiltonian canonical transformations.

Future datasets will enable cross-correlations between redshift space distortions (RSDs) and weak lensing (WL). While photometric lensing and clustering cross-correlations have provided some of the tightest cosmological constraints to date, it is not well understood how to optimally perform similar RSD/WL joint analyses in a lossless way. RSD is typically measured in 3D redshift space, but WL is inherently a projected signal, making angular statistics a natural choice for the combined analysis. Thus, we determine the amount of RSD information that can be extracted using projected statistics. Specifically we perform a Fisher analysis to forecast constraints and model bias comparing two different fingers-of-God models using both the 3D power spectrum $P(k,\mu )$ and tomographic $C(\ell )$. We find that because naïve tomographic projection mixes large scales with poorly modeled nonlinear radial modes, it does not provide competitive constraints to the 3D RSD power spectrum without the model bias becoming unacceptably large. This is true even in the limit of narrow tomographic bins. In light of this we propose a new radial weighting scheme which unmixes radial RSD scales in projection yielding competitive constraints to the 3D RSD power spectrum, while keeping the model bias small. This work lays the groundwork for optimal joint analyses of RSD and cosmic shear.

Using data from the Sloan Digital Sky Survey we study correlations between directions of galaxy angular momenta determined from images of spiral galaxies and various observables derived from the reconstructed initial conditions. We find an apparent systematic effect consistent with galaxy-orientation-dependent selection function. After restricting our attention to the brightest half of the galaxies where this systematic effect is presumed to be absent, we find hints of excess/deficit correlation for two observables. Interestingly, tidal torque theory predicts excess/deficit correlation in exactly these two observables. After correcting for the redshift space distortions, the significance of these correlations drops below $3\sigma$ threshold. We do not find any other systematic issues, but a thorough systematic analysis goes beyond the scope of this work.