By performing global fits to inverse beta-decay (IBD) yield measurements from existing neutrino experiments based at highly ${}^{235}\mathrm{U}$-enriched reactor cores and conventional low-enriched cores, we explore current direct bounds on neutrino production by the subdominant fission isotope ${}^{241}\mathrm{Pu}$. For this nuclide, we determine an IBD yield of ${\sigma }_{241}=8.16\pm 3.47{\mathrm{cm}}^2/\mathrm{fission}$, a value $(135\pm 58)\%$ that of current beta-conversion models. This constraint is shown to derive from the nonlinear relationship between the burn-in of ${}^{241}\mathrm{Pu}$ and ${}^{239}\mathrm{Pu}$ in conventional reactor fuel. By considering new hypothetical neutrino measurements at highly-enriched, low-enriched, mixed-oxide, and fast reactor facilities, we investigate the feasible limits of future knowledge of IBD yields for ${}^{235}\mathrm{U}$, ${}^{238}\mathrm{U}$, ${}^{239}\mathrm{Pu}$, ${}^{241}\mathrm{Pu}$, and ${}^{240}\mathrm{Pu}$. We find that the first direct measurement of the ${}^{240}\mathrm{Pu}$ IBD yield can be performed at plutonium-burning fast reactors, while a suite of correlated measurements at multiple reactor types can achieve precision in direct ${}^{238}\mathrm{U}$, ${}^{239}\mathrm{Pu}$, and ${}^{241}\mathrm{Pu}$ yield knowledge that meets or exceeds that of current theoretical predictions.

In this paper, we derive a $T\overline{T}$ deformed soft graviton theorem in terms of celestial holography. As a concrete example, it illustrates that a two-dimensional irrelevant deformation can be applied to a four-dimensional theory at the level of amplitudes.

We investigate generalized thermalization in an isolated free fermionic chain evolving from an out of equilibrium initial state through a sudden quench. We consider the quench where a fermionic chain is broken into two disjoint chains. We focus on the evolution of the local observables namely, occupation number, nearest neighbor hopping, information sharing and out-of-time-order correlations after the quench and study the relaxation of the observable, leading to generalized Gibbs ensemble for the system in the thermodynamic limit though it has been argued that noninteracting or free fermionic models in general do not relax to the generalized Gibbs ensemble (GGE). We obtain the light cone formed by the evolution of the observables along the fermionic lattice chain due to the sudden quench which abides by the Lieb-Robinson bound in quantum systems. We also analytically study a simpler model which captures the essential features of the system. Our analysis strongly suggest that the internal interactions within the system do not remain of much importance once the quench is sufficiently strong.

We study a conformally coupled scalar-tensor theory with a quartic potential possessing local conformal symmetry up to a boundary term. We show that requiring the restoration of the full local conformal symmetry fixes the counterterms that render the on-shell action finite. The building block of the resulting action is a conformally covariant tensor which is constructed out of the metric and the scalar field and it has the same conformal weight as the Weyl tensor. This allows us to obtain the counterterms for the scalar-tensor sector in a closed form. The finiteness of the conformally complete version of the action is suggestive on the validity of the conformal renormalization prescription. We extend this theory by adding the conformal gravity action and also the Einstein-AdS action written in MacDowell-Mansouri form. Even though the latter breaks the conformal symmetry, we find that the action is still renormalized provided a suitable falloff of the scalar field when considering asymptotically locally anti-de Sitter solutions. Black hole solutions in these theories are studied, for which the Hawking temperature and the partition function to first order in the saddle-point approximation are calculated, providing a concrete example of this renormalization scheme.

We present model-marginalized limits on mixed hot dark matter scenarios, which consider both thermal neutrinos and thermal QCD axions. A novel aspect of our analyses is the inclusion of small-scale cosmic microwave background (CMB) observations from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT), together with those from the Planck satellite and baryon acoustic oscillation (BAO) data. After marginalizing over a number of well-motivated nonminimal background cosmologies, the tightest 95% Confidential Level (CL) upper bound we obtain is 0.21 eV, both for $\sum m_{\nu }$ and $m_{\mathrm{a}}$, from the combination of ACT, Planck and BAO measurements. Restricting the analyses to the standard $\mathrm{\Lambda }\mathrm{CDM}$ picture, we find $\sum m_{\nu }<0.16\mathrm{eV}$ and $m_{\mathrm{a}}<0.18\mathrm{eV}$, both at 95% CL Interestingly, the best background cosmology is never found within the minimal $\mathrm{\Lambda }\mathrm{CDM}$ plus hot relics, regardless of the datasets exploited in the analyses. The combination of Planck with either BAO, SPT or ACT prefers a universe with a nonzero value of the running in the primordial power spectrum with strong evidence. Small-scale CMB probes, both alone and combined with BAO, either prefer, with substantial evidence, nonflat universes (as in the case of SPT) or a model with a time varying dark energy component (as in the case of ACT).

Halo models of large scale structure provide powerful and indispensable tools for phenomenological understanding of the clustering of matter in the Universe. While the halo model builds structures out of the superposition of haloes, defining halo profiles in their outskirts—beyond their virial radii—becomes increasingly ambiguous, as one cannot assign matter to individual haloes in a clear way. In this paper, we address this issue by finding a systematic definition of mean halo profile that can be extended to large distances—beyond the virial radius of the halo—and matched to simulation results. These halo profiles are compensated and are the key ingredients for the computation of cosmological correlation functions in an amended halo model. The latter, introduced in our earlier work [A. Y. Chen and N. Afshordi, Phys. Rev. D 101, 103522 (2020)], provides a more physically accurate phenomenological description of nonlinear structure formation, which respects conservation laws on large scales. Here, we show that this model can be extended from the matter auto-power spectrum to the halo-matter cross-power spectra by using data from $N$-body simulations. Furthermore, we find that this (dimensionless) definition of the compensated halo profile, $r^3\times \rho (r)/M_{200c}$, has a near-universal maximum in the small range of 0.03–0.04 around the virial radius, $r\simeq r_{200\mathrm{c}}$, nearly independent of the halo mass. The profiles cross zero into negative values in the halo outskirts—beyond $2–3\times r_{200\mathrm{c}}$—consistent with our previous results. We provide a preliminary fitting function for the compensated halo profiles (extensions of Navarro-Frenk-White profiles), which can be used to compute more physical observables in large scale structure.

We investigate the properties of dark energy halos in models with a nonminimal coupling in the dark sector. We show, using a quasistatic approximation, that a coupling of the mass of dark matter particles to a standard quintessence scalar field $\varphi$ generally leads to the formation of dark energy concentrations in and around compact dark matter objects. These are associated with regions where scalar field gradients are large and the dark energy equation of state parameter is close to $-1/3$. We find that the energy and radius of a dark energy halo are approximately given by $E_{\mathrm{halo}}\sim {\mathit{\beta }}^2\phi m$ and $r_{\mathrm{halo}}\sim \sqrt{\mathit{\beta }\phi (R/H)}$, where $\phi =Gm/(R{c}^2)$, $m$ and $R$ are, respectively, the mass and radius of the associated dark matter object, $\mathit{\beta }=-(8\pi G{)}^{-1/2}d\ln m/d\varphi$ is the nonminimal coupling strength parameter, $H$ is the Hubble parameter, $G$ is the gravitational constant, and $c$ is the speed of light in vacuum. We further show that current observational limits on $\mathit{\beta }$ over a wide redshift range lead to stringent constraints on $E_{\mathrm{halo}}/m$ and, therefore, on the impact of dark energy halos on the value of the dark energy equation of state parameter. We also briefly comment on potential backreaction effects that may be associated with the breakdown of the quasistatic approximation and determine the regions of parameter space where such a breakdown might be expected to occur.

Accurate and efficient modeling of the dynamics of binary black holes (BBHs) is crucial to their detection through gravitational waves (GWs), with LIGO/Virgo/KAGRA, and LISA in the future. Solving the dynamics of a BBH system with arbitrary parameters without simplifications (like orbit- or precession-averaging) in closed-form is one of the most challenging problems for the GW community. One potential approach is using canonical perturbation theory which constructs perturbed action-angle variables from the unperturbed ones of an integrable Hamiltonian system. Having action-angle variables of the integrable 1.5 post-Newtonian (PN) BBH system is therefore imperative. In this paper, we continue the work initiated by two of us in [Tanay et al., Phys. Rev. D 103, 064066 (2021)], where we presented four out of five actions of a BBH system with arbitrary eccentricity, masses, and spins, at 1.5PN order. Here we compute the remaining fifth action using a novel method of extending the phase space by introducing unmeasurable phase space coordinates. We detail how to compute all the frequencies, and sketch how to explicitly transform from the action-angle variables to the usual positions and momenta. This analytically solves the dynamics at 1.5PN. This lays the groundwork to analytically solve the conservative dynamics of the BBH system with arbitrary masses, spins, and eccentricity, at higher PN order, by using canonical perturbation theory.

Within the relativistic mean-field model, we investigate the properties of dark matter (DM) admixed neutron stars, considering nonrotating objects made of isotropic matter. We adopt the IOPB-I hadronic equation of state (EOS) by assuming that the fermionic DM within supersymmetric models has already been accreted inside the neutron star (NS). The impact of DM on the mass-radius relationships and the radial oscillations of pulsating DM admixed neutron stars (with and without the crust) are explored. It is observed that the presence of DM softens the EOS, which in turn lowers the maximum mass and its corresponding radius. Moreover, adding DM results in higher frequencies of pulsating objects, and hence we show the linearity of the fundamental mode frequency of canonical NS with DM Fermi momentum. We also investigate the profile of eigenfunctions solving the Sturm-Liouville boundary value problem and verify its validity. Further, we study the stability of NSs considering the fundamental mode frequency variation with the mass of the star and verify the stability criterion $\partial M/\partial {\rho }_c>0$. Finally, the effect of the crust on the large frequency separation for different DM Fermi momenta is shown as well.

High-energy neutrinos from astrophysical transients serve as a probe of neutrino physics beyond the Standard Model. In particular, nonstandard interaction of neutrinos with the cosmic neutrino background or dark matter (DM) may have imprints on not only their spectra but also the arrival and time-delay distributions. Assuming that the interaction occurs at most once during the neutrino propagation, we provide general analytic formulas for light curves of the neutrino echoes induced by BSM. The formulas can be used for constraining neutrino-neutrino scattering, neutrino-DM scattering, and other scattering processes experienced by relativistic particles.

TianQin is a proposed space-based gravitational-wave detector designed to operate in circular high Earth orbits. As a sequel to [Zhang et al. Phys. Rev. D 103, 062001 (2021)], this work provides an analytical model to account for the perturbing effect of the Earth’s gravity field on the range acceleration noise between two TianQin satellites. For such an “orbital noise,” the Earth’s contribution dominates above $5\times {10}^{-5}\mathrm{Hz}$ in the frequency spectrum, and the noise calibration and mitigation, if needed, can benefit from in-depth noise modeling. Our model derivation is based on Kaula’s theory of satellite gravimetry with Fourier-style decomposition and uses circular reference orbits as an approximation. To validate the model, we compare the analytical and numerical results in two main scenarios. First, in the case of the Earth’s static gravity field, both noise spectra are shown to agree well with each other at various orbital inclinations and radii, confirming our previous numerical work while providing more insight. Second, the model is extended to incorporate the Earth’s time-variable gravity. Particularly relevant to TianQin, we augment the formulas to capture the disturbance from the Earth’s free oscillations triggered by earthquakes, of which the mode frequencies enter TianQin’s measurement band above 0.1 mHz. The analytical model may find applications in gravity environment monitoring and noise-reduction pipelines for TianQin.

The homogeneous Bethe-Salpeter equation (BSE) of a $(1/2{)}^{+}$ bound system, that has both fermionic and bosonic degrees of freedom, that we call a mock nucleon, is studied in Minkowski space, in order to analyze the chiral limit in covariant gauges. After adopting an interaction kernel built with a one-particle exchange, the $\chi$-BSE is numerically solved by means of the Nakanishi integral representation and light-front projection. Noteworthy, the chiral limit induces a scale invariance of the model and consequently generates a wealth of striking features: (i) it reduces the number of nontrivial Nakanishi weight functions to only one; (ii) the form of the surviving weight function has a factorized dependence on the two relevant variables, compact and noncompact; and (iii) the coupling constant becomes an explicit function of the real exponent governing the power-law falloff of the nontrivial Nakanishi weight function. The thorough investigation at large transverse momentum of light-front Bethe-Salpeter amplitudes, obtained with massive constituents, provides a confirmation of the expected universal power-law falloff, with exponents predicted by our nonperturbative framework. Finally, one can shed light on the exponents that govern the approach to the upper extremum of the longitudinal-momentum fraction distribution function of the mock nucleon, when the coupling constant varies.

In this work, we study the propagation and absorption of plasma waves in the chiral Maxwell-Carroll-Field-Jackiw (MCFJ) electrodynamics. The Maxwell equations are rewritten for a cold, uniform, and collisionless fluid plasma model, allowing us to determine the new refractive indices and propagating modes. The cases of propagation parallel and orthogonal to the magnetic field are examined considering a purely timelike CFJ background that plays the role of the magnetic conductivity chiral parameter. The collective electromagnetic modes are associated with four distinct refractive indices associated with right-circularly polarized and left-circularly polarized waves. For each index, the propagation and absorption zones are illustrated for some specific parameter values. In low-frequency regime, we have obtained modified helicons with right- and left-circularly polarizations. The optical behavior is investigated by means of the rotatory power (RP) and dichroism coefficient. The existence of a negative refraction zone enhances the rotatory power. It is also observed RP sign reversal, a feature of rotating plasmas.

The Nambu–Jona-Lasinio model is widely used to study strong-interaction phenomena in vacuum and quark matter. Since the model is nonrenormalizable, one needs to work within a specific regularization scheme to obtain finite results. Here we show that a commonly used cutoff regularization scheme leads to unphysical results, such as superluminal speed of sound and wrong high-temperature behavior of the specific heat and other thermodynamical quantities. Such a troublesome feature of the cutoff regularization invalidates the model for temperature and baryon density values relevant to the phenomenology of heavy-ion collisions and compact stars. We show that the source of the problems stems from cutting off momentum modes in finite integrals depending on thermal distribution functions in the grand canonical potential. The problems go away when taking into account the full momentum range of those integrals. Explicit examples are worked out in the SU(2)-flavor version of the model.

We study the effects of nonholomorphic soft supersymmetry-breaking terms added to the minimal supersymmetric Standard Model on the Higgs-boson masses. The calculation of the nonholomorphic contributions is performed at the one-loop level in the Feynman diagrammatic approach. After generating a feynarts model file with the help of sarah, we calculate the renormalized Higgs-boson self-energies at the one-loop level using the feynarts/formcalc setup. The results obtained from feynarts/formcalc are fed to feynhiggs to estimate the contributions to the neutral $CP$-even Higgs-boson masses, $M_{h,H}$, as well as to the charged Higgs-boson mass, $M_{H^{\pm }}$. For the specific set of parameter points that we choose for this study, the nonholomorphic soft-term contributions to the light $CP$-even Higgs-boson mass, $M_h$, contrary to claims in the literature, turn out to be very small. For the heavy $CP$-even Higgs-boson mass, $M_H$, as well as for the charged Higgs-boson mass, $M_{H^{\pm }}$, the contributions can be substantially larger for some parts of parameter space.

A study of two-pion scattering for the isospin channels, $I=0$ and $I=2$, using lattice QCD is presented. Möbius domain-wall fermions, on top of the Iwasaki-DSDR gauge action for gluons with periodic boundary conditions, are used for the lattice computations, which are carried out on two ensembles of gauge field configurations generated by the RBC and UKQCD Collaborations with physical masses, inverse lattice spacings of 1.023 and 1.378 GeV, and spatial extents of $L=4.63$ and 4.58 fm, respectively. The all-to-all propagator method is employed to compute a matrix of correlation functions of two-pion operators. The generalized eigenvalue problem (GEVP) is solved for a matrix of correlation functions to extract phase shifts with multiple states—two pions with a nonzero relative momentum, as well as two pions at rest. Our results for phase shifts for both the $I=0$ and $I=2$ channels are consistent with the Roy equation and chiral perturbation theory, though at this preliminary stage our errors for $I=0$ are large. An important outcome of this work is that we are successful in extracting two-pion excited states, which are useful for studying $K\to \pi \pi$ decay, on physical-mass ensembles using the GEVP.

Semidefinite programs can be constructed to provide a nonperturbative view of the zero-temperature behavior of quantum systems. Past work has found that small semidefinite programs (relative to the dimension of Hilbert space) yield quantitatively accurate estimates for the ground-state energy and expectation values. This paper examines the properties of these semidefinite programs when applied to lattice-regulated field theories exhibiting fermion sign problems. Specifically on the finite-density Thirring model, small semidefinite programs still yield quantitatively accurate results, and there is no indication that these methods encounter exponential costs (analogous to the fermion sign problem) at finite chemical potential.

Parametrizing TMD parton densities and fragmentation functions in ways that consistently match their large transverse-momentum behavior in standard collinear factorization has remained notoriously difficult. We show how the problem is solved in a recently introduced set of steps for combining perturbative and nonperturbative transverse momentum in TMD factorization. Called a “bottom-up” approach in a previous article, here we call it a “hadron structure oriented” (HSO) approach to emphasize its focus on preserving a connection to the TMD parton model interpretation. We show that the associated consistency constraints improve considerably the agreement between parametrizations of TMD functions and their large-$k_T$ behavior, as calculated in collinear factorization. The procedure discussed herein will be important for guiding future extractions of TMD parton densities and fragmentation functions and for testing TMD factorization and universality. We illustrate the procedure with an application to semi-inclusive deep inelastic scattering (SIDIS) structure functions at an input scale $Q_0$, and we show that there is improved consistency between different methods of calculating at moderate transverse momentum. We end with a discussion of plans for future phenomenological applications.

High-energy heavy-ion collisions generate an extremely strong magnetic field which plays a key role in a number of novel quantum phenomena in quark-gluon plasma (QGP), such as the chiral magnetic effect. However, due to the complexity in theoretical modelings of the coupled electromagnetic fields and the QGP system, especially in the preequilibrium stages, the lifetime of the magnetic field in the QGP medium remains undetermined. We establish, for the first time, a kinetic framework to study the dynamical decay of the magnetic field in the early stages of a weakly coupled QGP by solving the coupled Boltzmann and Maxwell equations. We find that at late times a magnetohydrodynamical description of the coupled system emerges. With respect to realistic collisions at RHIC and the LHC, we estimate the residual strength of the magnetic field in the QGP when the system starts to evolve hydrodynamically.