Attempts at constraining theories of late time accelerated expansion often assume broad priors for the parameters in their phenomenological description. Focusing on shift-symmetric scalar-tensor theories with standard gravitational wave speed, we show how a more careful analysis of their dynamical evolution leads to much narrower priors. In doing so, we propose a simple and accurate parametrization of these theories, capturing the redshift dependence of the equation of state, $w(z)$, and the kinetic braiding parameter, ${\alpha }_{\mathrm{B}}(z)$, with only two parameters each, and derive their statistical distribution (also known as theoretical priors) that fit the cosmology of the underlying model. We have considered two versions of the shift-symmetric model, one where the energy density of dark energy is given solely by the scalar field and another where it also has a contribution from the cosmological constant. By including current data, we show how theoretical priors can be used to improve constraints by up to an order of magnitude. Moreover, we show that shift-symmetric theories without a cosmological constant are observationally viable. We work up to quartic order in first derivatives of the scalar in the action, and our results suggest this truncation is a good approximation to more general shift-symmetric theories. This work establishes an actionable link between phenomenological parametrizations and Lagrangian-based theories, the two main approaches to test cosmological gravity and cosmic acceleration.

Current and future generations of intensity mapping surveys promise dramatic improvements in our understanding of galaxy evolution and large-scale structure. An intensity map provides a census of the cumulative emission from all galaxies in a given region and redshift, including faint objects that are undetectable individually. Furthermore, cross-correlations between line intensity maps and galaxy redshift surveys are sensitive to the line intensity and clustering bias without the limitation of cosmic variance. Using the Fisher information matrix, we derive simple expressions describing sensitivities to the intensity and bias obtainable for cross-correlation surveys, focusing on cosmic variance evasion. Based on these expressions, we conclude that the optimal sensitivity is obtained by matching the survey depth, defined by the ratio of the clustering power spectrum to noise in a given mode, between the two surveys. We find that midinfrared to far-infrared space telescopes could benefit from this technique by cross-correlating with coming galaxy redshift surveys such as those planned for the Nancy Grace Roman Space Telescope, allowing for sensitivities beyond the cosmic variance limit. Our techniques can therefore be applied to survey design and requirements development to maximize the sensitivities of future intensity mapping experiments to tracers of galaxy evolution and large-scale structure cosmology.

The hypothesis that strange quark matter is the true ground state of matter has been investigated for almost four decades, but only a few works have explored the dynamics of binary systems of quark stars. This is partly due to the numerical challenges that need to be faced when modeling the large discontinuities at the surface of these stars. After adopting a suitable definition of the baryonic mass of strange quark matter, we introduce a novel technique in which a very thin crust is added to the equation of state of strange quark matter to produce a smooth and gradual change of the specific enthalpy across the star and up to its surface. The introduction of the crust has been carefully tested by considering the oscillation properties of isolated quark stars, showing that the response of the simulated quark stars matches accurately the perturbative predictions. Using this technique, we have carried out the first fully general-relativistic simulations of the merger of quark-star binaries finding several important differences between quark-star binaries and hadronic-star binaries with the same mass and comparable tidal deformability. In particular, we find that the dynamical mass loss is $\sim 20\%$ smaller than that coming from a corresponding hadronic binary. In addition, quark-star binaries have merger and postmerger frequencies that obey the same quasiuniversal relations derived from hadron stars if expressed in terms of the tidal deformability, but not when expressed in terms of the average stellar compactness. Hence, it may be difficult to distinguish the two classes of stars if no information on the stellar radius is available. Finally, differences are found in the distributions in velocity and entropy of the ejected matter, for which quark stars have much smaller tails. Whether these differences in the ejected matter will leave an imprint in the electromagnetic counterpart and nucleosynthetic yields remains unclear, calling for the construction of an accurate model for the evaporation of the ejected quarks into nucleons.

The discovery of the coalescence of binary neutron star GW170817 was a watershed moment in the field of gravitational wave astronomy. Among the rich variety of information that we were able to uncover from this discovery was the first non-electromagnetic measurement of the neutron star radius, and the cold nuclear equation of state. It also led to a large equation of state model selection study from gravitational-wave data. In those studies Bayesian nested sampling runs were conducted for each candidate equation of state model to compute their evidence in the gravitational-wave data. Such studies, though invaluable, are computationally expensive and require repeated, redundant, computation for any new models. We present a novel technique to conduct model selection of equation of state in an extremely rapid fashion ($\sim$ minutes) on any arbitrary model. We test this technique against the results of a nested-sampling model selection technique published earlier by the LIGO/Virgo collaboration, and show that the results are in good agreement with a median fractional error in Bayes factor of about 10%, where we assume that the true Bayes factor is calculated in the aforementioned nested sampling runs. We found that the highest fractional error occurs for equation of state models that have very little support in the posterior distribution, thus resulting in large statistical uncertainty. We then used this method to combine multiple binary neutron star mergers to compute a joint-Bayes factor between equation of state models. This is achieved by stacking the evidence of the individual events and computing the Bayes factor from these stacked evidences for each pairs of equation of state.

High to ultrahigh energy neutrino detectors can uniquely probe the properties of dark matter $\chi$ by searching for the secondary neutrinos produced through annihilation and/or decay processes. We evaluate the sensitivities to dark matter thermally averaged annihilation cross section $⟨\sigma v⟩$ and partial decay width ${\mathrm{\Gamma }}_{\chi \to \nu \overline{\nu }}$ (in the mass scale ${10}^7\le m_{\chi }/\mathrm{GeV}\le {10}^{15}$) for next generation observatories like POEMMA (Probe of Extreme Multi-Messenger Astrophysics) and GRAND (Giant Radio Array for Neutrino Detection). We show that in the range ${10}^7\le m_{\chi }/\mathrm{GeV}\le {10}^{11}$, space-based Cherenkov detectors like POEMMA have the advantage of full-sky coverage and rapid slewing, enabling an optimized dark matter observation strategy focusing on the Galactic Center. We also show that ground-based radio detectors such as GRAND can achieve high sensitivities and high duty cycles in radio quiet areas. We compare the sensitivities of next generation neutrino experiments with existing constraints from IceCube and updated 90% C.L. upper limits on $⟨\sigma v⟩$ and ${\mathrm{\Gamma }}_{\chi \to \nu \overline{\nu }}$ using results from the Pierre Auger Collaboration and Antarctic Impulsive Transient Antenna. We show that in the range ${10}^7\le m_{\chi }/\mathrm{GeV}\le {10}^{11}$, POEMMA and GRAND10k will improve the neutrino sensitivity to particle dark matter by factors of 2 to 10 over existing limits, whereas GRAND200k will improve this sensitivity by 2 orders of magnitude. In the range ${10}^{11}\le m_{\chi }/\mathrm{GeV}\le {10}^{15}$, POEMMA’s fluorescence observation mode will achieve an unprecedented sensitivity to dark matter properties. Finally, we highlight the importance of the uncertainties related to the dark matter distribution in the galactic halo, using the latest fit and estimates of the galactic parameters.

The accretion of a spherically symmetric, collisionless kinetic gas cloud onto a Schwarzschild black hole is analyzed. Whereas previous studies have treated this problem by specifying boundary conditions at infinity, here the properties of the gas are given at a sphere of finite radius. The corresponding steady-state solutions are computed using four different models with an increasing level of sophistication, starting with the purely radial infall of Newtonian particles and culminating with a fully general relativistic calculation in which individual particles have angular momentum. The resulting mass accretion rates are analyzed and compared with previous models, including the standard Bondi model for a hydrodynamic flow. We apply our models to the supermassive black holes Sgr A* and M87*, and we discuss how their low luminosity could be partially explained by a kinetic description involving angular momentum. Furthermore, we get results consistent with previous model-dependent bounds for the accretion rate imposed by rotation measures of the polarized light coming from Sgr A* and with estimations of the accretion rate of M87* from the Event Horizon Telescope collaboration. Our methods and results could serve as a first approximation for more realistic black hole accretion models in various astrophysical scenarios in which the accreted material is expected to be nearly collisionless.

The ongoing development of the space-based laser interferometer missions is aiming at unprecedented gravitational wave detections in the millihertz frequency band. The spaceborne nature of the experimental setups leads to a degree of subtlety regarding the otherwise overwhelming laser frequency noise. The cancellation of the latter is accomplished through the time-delay interferometry technique. Moreover, to eventually achieve the desired noise level, the phase fluctuations of the onboard ultrastable oscillator must also be suppressed. This can be fulfilled by introducing sideband signals which, in turn, give rise to an improved cancellation scheme accounting for the clock-jitter noise. Nonetheless, for certain Sagnac-type interferometry layouts, it can be shown that resultant residual clock noise found in the literature can be further improved. In this regard, we propose refined cancellation combinations for two specific clock noise patterns. This is achieved by employing the so-called geometric time-delay interferometry interpretation. It is shown that for specific Sagnac combinations, the residual noise diminishes significantly to attain the experimentally acceptable sensitivity level. Moreover, we argue that the derived combination, in addition to the existing ones in the literature, furnishes a general-purpose cancellation scheme that serves for arbitrary time-delay interferometry combinations. The subsequential residual noise will only involve factors proportional to the commutators between the delay operators. Our arguments reside in the form of the clock noise expressed in terms of the coefficients of the generating set of the first module of syzygies, the linear combination of which originally constitutes the very solution for laser noise reduction.

We study a cross-shaped cavity filled with superfluid ${}^4\mathrm{He}$ as a prototype resonant-mass gravitational wave detector. Using a membrane and a reentrant microwave cavity as a sensitive optomechanical transducer, we were able to observe the thermally excited high-$Q$ acoustic modes of the helium at 20 mK temperature and achieved a strain sensitivity of $8\times {10}^{-19}{\mathrm{Hz}}^{-1/2}$ to gravitational waves. To facilitate the broadband detection of continuous gravitational waves, we tune the kilohertz-scale mechanical resonance frequencies up to $173\mathrm{Hz}/\mathrm{bar}$ by pressurizing the helium. With reasonable improvements, this architecture will enable the search for gravitational waves in the $1–30\mathrm{kHz}$ range, relevant for a number of astrophysical sources both within and beyond the Standard Model.

We consider an effective field theory framework with three Standard Model (SM) gauge singlet right-handed neutrinos, and an additional SM gauge singlet scalar field. The framework successfully generates eV masses of light neutrinos via the seesaw mechanism, and accommodates a feebly interacting massive particle (FIMP) as a dark matter candidate. Two of the gauge singlet neutrinos participate in neutrino mass generation, while the third gauge singlet neutrino is a FIMP dark matter. We explore the correlation between the vev (vacuum expectation value) of the gauge singlet scalar field which translates as mass of the BSM Higgs, and the mass of dark matter, which arises due to the relic density constraint. We furthermore explore the constraints from the light neutrino masses in this setup. We chose the gauge singlet BSM Higgs in this framework in the TeV scale. We perform a detailed collider analysis to explore the discovery prospect of the TeV scale BSM Higgs through its difatjet signature, at a future $pp$ collider which can operate with $\sqrt{s}=100\mathrm{TeV}$ c.m. energy.

Gravitational wave (GW) memory is an important prediction of general relativity. Existing works on the GW memory detection targeted the nonoscillatory strain. It is hard for the wave strain analysis method to detect the GW memory due to its quasidirect current behavior and weakness. We implement a completely different scheme in this work to estimate the GW memory. In this scheme, we first apply the Bondi-Metzner-Sachs method to calculate the GW memory of a binary black hole based on numerical relativity simulation. Then we construct a surrogate model to relate a binary black hole’s parameters and the GW memory. Afterwards we apply this surrogate model together with Bayesian techniques to estimate the GW memory of the 48 binary black hole events recorded in GWTC-2. The GW memory corresponding to all 48 events has been estimated.

We address the physical origin of the ultrarelativistic prompt emission (UPE) phase of GRB 190114C observed in the interval $t_{\mathrm{rf}}=1.9–3.99\mathrm{s}$, by the Fermi-GBM in 10 keV–10 MeV energy band. Thanks to the high signal-to-noise ratio of Fermi-GBM data, a time-resolved spectral analysis has evidenced a sequence of similar blackbody plus cutoff power-law spectra ($\mathrm{BB}+\mathrm{CPL}$), on ever decreasing time intervals during the entire UPE phase. We assume that during the UPE phase, the “inner engine” of the GRB, composed of a Kerr black hole (BH) and a uniform test magnetic field $B_0$, aligned with the BH rotation axis, operates in an overcritical field $|\mathbf{E}|\ge E_c$, where $E_c=m_e^2{c}^3/(e\hslash )$, being $m_e$ and $-e$ the mass and charge of the electron. We infer an $e^{+}{e}^{-}$ pair electromagnetic plasma in presence of a baryon load, a PEMB pulse, originating from a vacuum polarization quantum process in the inner engine. This initially optically thick plasma self-accelerates, giving rise at the transparency radius to the MeV radiation observed by Fermi-GBM. At times $t_{\mathrm{rf}}>3.99\mathrm{s}$, the electric field becomes undercritical, $|\mathbf{E}|<E_c$, and the inner engine, as previously demonstrated, operates in the classical electrodynamics regime and generate the GeV emission. During both the “quantum” and the “classical” electrodynamics processes, we determine the time varying mass and spin of the Kerr BH in the inner engine, fulfilling the Christodoulou-Hawking-Ruffini mass-energy formula of a Kerr BH. For the first time, we quantitatively show how the inner engine, by extracting the rotational energy of the Kerr BH, produces a series of PEMB pulses. We follow the quantum vacuum polarization process in sequences with decreasing time bins. We compute the Lorentz factors, the baryon loads and the radii at transparency, as well as the value of the magnetic field, $B_0$, assumed to be constant in each sequence. The fundamental hierarchical structure, linking the quantum electrodynamics regime to the classical electrodynamics regime, is characterized by the emission of “blackholic quanta” with a timescale $\tau \sim {10}^{-9}\mathrm{s}$, and energy $\mathcal{E}\sim {10}^{45}\mathrm{erg}$.

Oscillons are long-lived, slowly radiating solutions of nonlinear classical relativistic field theories. Recently it was discovered that in one spatial dimension their decay may proceed in “staccato” bursts. Here we perform a systematic numerical study to demonstrate that although this behavior is not confined to one spatial dimension, it quickly becomes unobservable when the dimension of space is increased, at least for the class of potentials considered here. To complete the picture we also present explicit results on the dimension dependence of the collapse instability observed for three-dimensional oscillons.

In this work, we will present the first complete calculation of the one-loop longitudinal photon-to-quark-antiquark light cone wave function, with massive quarks. The quark masses are renormalized in the pole mass scheme. The result is used to calculate the next-to-leading order correction to the high energy deep inelastic scattering longitudinal structure function on a dense target in the dipole factorization framework. For massless quarks the next-to-leading order correction was already known to be sizeable, and our result makes it possible to evaluate it also for massive quarks.

The hard thermal loop (HTL) effective field theory of QED can be derived from the classical limit of transport theory, corresponding to the leading term in a gradient expansion of the quantum approach. In this paper, we show that power corrections to the HTL effective Lagrangian of QED can also be obtained from transport theory by including higher orders in such gradient expansion. The gradient expansion is increasingly infrared (IR) divergent, but the correction that we compute is IR finite. We employ dimensional regularization, and show that this result comes after a cancellation of divergencies between the vacuum and medium contributions. While the transport framework is an effective field theory of the long distance physics of the plasma, we show that it correctly reproduces the correct QED ultraviolet divergencies associated with the photon wave function renormalization.

The question whether the Higgs boson is connected to additional $CP$ violation is one of the driving forces behind precision studies at the Large Hadron Collider. In this work, we investigate the $CP$ structure of the top quark Yukawa interaction—one of the most prominent places for searching for New Physics—through Higgs boson loops in top quark pair production. We calculate the electroweak corrections including arbitrary $CP$ mixtures at next-to-leading-order in the Standard Model Effective Field Theory. This approach of probing Higgs boson degrees of freedom relies on the large $t\overline{t}$ cross section and the excellent perturbative control. In addition, we consider all direct probes with on-shell Higgs boson production in association with a single top quark or top quark pair. This allows us to contrast loop sensitivity versus on-shell sensitivity in these fundamentally different process dynamics. We find that loop sensitivity in $t\overline{t}$ production and on-shell sensitivity in $t\overline{t}H$ and $tH$ provide complementary handles over a wide range of parameter space.

We study canonical and affine versions of the quantized covariant Euclidean Higgs scalar field-theory for two real fields on four dimensional lattices through the Monte Carlo method. We calculate the two-point function near the continuum limit at finite volume.

In a previous work we have studied the isospin $1/2$ lowest positive and negative parity states of the pentaquark $uudc\overline{c}$, in a constituent quark model with a linear confinement and an SU(4) flavor-spin hyperfine interaction and we compared the results with the $P_c^{+}(4312)$, $P_c^{+}(4440)$ and $P_c^{+}(4457)$ pentaquarks observed at LHCb in 2019. Here we extend the previous work by calculating ratios of decay rates of the $P_c$ pentaquarks to $J/\mathrm{\Psi }$ and ${\eta }_c$ and similarly the ratio of decay rates to ${\mathrm{\Lambda }}_c{\overline{D}}^{*}$ and ${\mathrm{\Lambda }}_c\overline{D}$. Our predictions are based on the $\mathrm{SU}(4)\times \mathrm{SU}(2)$ structure of compact pentaquarks.

We propose a method to examine how a parton shower sums large logarithms. In this method, one works with an appropriate integral transform of the distribution for the observable of interest. Then, one reformulates the parton shower so as to obtain the transformed distribution as an exponential for which one can compute the terms in the perturbative expansion of the exponent. We apply this general program to the thrust distribution in electron-positron annihilation, using several shower algorithms. Of the approaches that we use, the most generally applicable is to compute some of the perturbative coefficients in the exponent by numerical integration and to test whether they are consistent with next-to-leading-log summation of the thrust logarithms.

We introduce, within the refined Gribov-Zwanziger setup, a composite Becchi-Rouet-Stora-Tyutin (BRST) invariant fermionic operator coupled to the inverse of the Faddeev-Popov operator. As a result, an effective BRST invariant action in Euclidean space-time is constructed, enabling us to pave the first step towards the study of the behavior of the fermion propagator in the infrared region in the class of the linear covariant gauges. The aforementioned action is proven to be renormalizable to all orders by means of the algebraic renormalization procedure.

We reconsider the problem of transverse momentum broadening of a highly energetic parton suffering multiple scatterings in dense colored media, such as the thermal quark-gluon plasma or large nuclei. In the framework of Molière’s theory of multiple scattering we rederive a simple analytic formula, to be used in jet quenching phenomenology, that accounts for both the multiple soft and hard Rutherford scattering regimes. Further, we discuss the sensitivity of momentum broadening to modeling of the nonperturbative infrared sector by presenting a detailed analytic and numerical comparison between the two widely used models in phenomenology: the Hard Thermal Loop and the Gyulassy-Wang potentials. We show that for the relevant values of the parameters the nonuniversal, model dependent contributions are negligible at LHC, RHIC and EIC energies, thus consolidating the predictive power of jet quenching theory.