We study quark and gluon jets separately using public collider data from the CMS experiment. Our analysis is based on $2.3{\mathrm{fb}}^{-1}$ of proton-proton collisions at $\sqrt{s}=7\mathrm{TeV}$, collected at the Large Hadron Collider in 2011. We define two nonoverlapping samples via a pseudorapidity cut—central jets with $|\eta |\le 0.65$ and forward jets with $|\eta |>0.65$—and employ jet topic modeling to extract individual distributions for the maximally separable categories. Under certain assumptions, such as sample independence and mutual irreducibility, these categories correspond to “quark” and “gluon” jets, as given by a recently proposed operational definition. We consider a number of different methods for extracting reducibility factors from the central and forward datasets, from which the fractions of quark jets in each sample can be determined. The greatest stability and robustness to statistical uncertainties is achieved by a novel method based on parametrizing the end points of a receiver operating characteristic curve. To mitigate detector effects, which would otherwise induce unphysical differences between central and forward jets, we use the omnifold method to perform central value unfolding. As a demonstration of the power of this method, we extract the intrinsic dimensionality of the quark and gluon jet samples, which exhibit Casimir scaling, as expected from the strongly ordered limit. To our knowledge, this work is the first application of full phase space unfolding to real collider data (albeit without a full systematics analysis), and the first application of topic modeling using a machine-learned classifier to extract separate quark and gluon distributions at the LHC.

We consider heavy meson-antimeson pairs and their coupling to quarkonium in the context of nonrelativistic effective field theories (EFTs) incorporating the adiabatic expansion. We work out all the leading order couplings of quarkonium to heavy meson-antimeson pairs and obtain their contributions to the masses and widths of quarkonia. We match the new potentials terms to nonrelativistic QCD. Using the available lattice data for the coupled system of quarkonium and the lowest lying heavy meson-antimeson pair, we extract the mixing potential and use it to compute numerically the contributions of $D\overline{D}(B\overline{B})$ and $D_s{\overline{D}}_s(B_s{\overline{B}}_s)$ to the masses and widths of the charmonium (bottomonium) states for $l=0$, 1, 2 and up to $n=6$ covering the states in threshold region. When a quarkonium state and a heavy meson-antimeson pair are separated by small energy gaps, their interactions can be described by a threshold EFT with contact interactions. We work out the matching between the two EFTs obtaining the couplings of the threshold EFT in terms of the mixing potential and quarkonium wave functions.

The existence of de Sitter solutions and their stability within string theory became, in recent years, one of the central research questions within the string theory community. The so-called de Sitter conjecture states that the de Sitter vacua are unstable within string theory. Here, we study the de Sitter solutions in string theory and their stability in the time direction using the $O(d,d)$ symmetry approach allowing for the calculation of the generic form of the string theory effective action. We study the undiscussed case of the constant generalized dilaton as well as the general form of dilaton couplings. Our findings suggest that de Sitter solutions are unstable for the constant generalized dilaton both with and without matter. Furthermore, we found that in order for the theory to be weakly coupled the general form of dilaton coupling is in the form of a cosmological constant.

Multiband observations of coalescing stellar-mass black holes binaries could deliver valuable information on the formation of such sources and potential deviations from general relativity. Some of these binaries might be first detected by the space-based detector LISA and, then, several years later, observed with ground-based detectors. Due to large uncertainties in astrophysical models, it is hard to predict the population of such binaries that LISA could observe. In this work, we assess the ability of LISA to detect the events of the third catalog of gravitational wave sources released by the LIGO/Virgo/KAGRA collaboration. We consider the possibility of directly detecting the source with LISA and performing archival searches in the LISA data stream, after the event has been observed with ground-based detectors. We also assess how much could LISA improve the determination of source parameters. We find that it is not guaranteed that any event other than GW150914 would have been detected. Nevertheless, if any event is detected by LISA, even with a very low signal-to-noise ratio, the measurement of source parameters would improve by combining observations of LISA and ground based detectors, in particular for the chirp mass.

In [J. P. B. Brito et al., Phys. Rev. D 104, 124085 (2021).], we studied the scalar radiation emitted by a source orbiting a Schwarzschild–anti–de Sitter black hole along circular geodesics. We presented results for the emitted power in the context of quantum field theory in curved spacetimes. We computed the emitted power for a region of the parameter space corresponding to large black holes when compared to the anti–de Sitter radius. In this addendum we investigate the regime of small black holes, i.e., the regime of $M^2\mathrm{\Lambda }\lesssim 0$. In this regime, the emitted power, as a function of the source’s angular velocity, exhibits resonant peaks associated with quasinormal frequencies.

The quest for distinguishing black holes from horizonless compact objects using gravitational wave signals from coalescing compact binaries can be helped by utilizing the phenomenon of tidal heating, which leaves its imprint on the binary waveforms through the horizon parameters. These parameters, defined as $H_1$ and $H_2$ with $H_{1,2}\in [0,1]$ for the two compact objects, are combined with the binary components’ masses and spins to form two new parameters, $H_{\mathrm{eff}5}$ and $H_{\mathrm{eff}8}$, to minimize their covariances in parameter estimation studies. In this work, we investigate the effects of tidal heating on gravitational waves to probe the observability of these effective parameters. We use a post-Newtonian waveform that includes the phase contribution due to tidal heating as a function of $H_{\mathrm{eff}5}$ and $H_{\mathrm{eff}8}$, and we examine their $1\sigma$ measurement errors as well as the covariances between them mainly using the Fisher matrix approach. Since this approach works well for high signal-to-noise ratios, we focus primarily on the third-generation (3G) gravitational wave detectors Einstein Telescope and Cosmic Explorer and use the second-generation (2G) detector network of LIGO (Hanford, Livingston) and Virgo for comparison. We study how the errors vary with the binaries’ total mass, mass ratio, luminosity distance, and component spins. We find that the regions in the total binary mass where measurements of $H_{\mathrm{eff}5}$ and $H_{\mathrm{eff}8}$ are most precise are $\sim 20–30M_{\odot }$ for LIGO-Virgo and $\sim 50–80M_{\odot }$ for the 3G detectors. Higher component spins allow more precise measurements of $H_{\mathrm{eff}5}$ and $H_{\mathrm{eff}8}$. For a binary situated at 200 Mpc with component masses $12M_{\odot }$ and $18M_{\odot }$, equal spins ${\chi }_1={\chi }_2=0.8$, and $H_{\mathrm{eff}5}=0.6$, $H_{\mathrm{eff}8}=12$, the $1\sigma$ errors in these two parameters are $\sim 0.01$ and $\sim 0.04$, respectively, in 3G detectors. These estimates suggest that precise measurements of the horizon parameters are possible in third-generation detectors, making tidal heating a potential tool to identify the presence or absence of horizons in coalescing compact binaries. We substantiate our results from Fisher studies with a set of Bayesian simulations.

In gauge invariant theories, like Einstein-Maxwell theory, physical observables should be gauge invariant. In particular, mass, entropy, angular momentum, electric charge, and their respective chemical potentials, temperature, horizon angular velocity, and electric potential, which appear in the laws of black hole thermodynamics, should be gauge invariant. In the usual construction of the laws of black hole thermodynamics, gauge invariance of the intensive quantities is subtle; here, we remedy this and provide a gauge invariant derivation and the proof of the zeroth and first laws of black hole thermodynamics.

Gravitational waves from the coalescences of black holes and neutron stars afford us the unique opportunity to determine the sources’ properties, such as their masses and spins, with unprecedented accuracy. To do so, however, theoretical models of the emitted signal that are (i) extremely accurate and (ii) computationally highly efficient are necessary. The inclusion of more detailed physics such as higher-order multipoles and relativistic spin-induced orbital precession increases the complexity and hence also computational cost of waveform models, which presents a severe bottleneck to the parameter inference problem. A popular method to generate waveforms more efficiently is to build a fast surrogate model of a slower one. In this paper, we show that traditional surrogate modeling methods combined with artificial neural networks can be used to build a computationally highly efficient while still accurate emulation of multipolar time-domain waveform models of precessing binary black holes. We apply this method to the state-of-the-art waveform model seobnr4phm and find significant computational improvements: On a traditional CPU, the typical generation of a single waveform using our neural network surrogate seobnn_v4phm_4dq2 takes 18 ms for a binary black hole with a total mass of $44M_{\odot }$ when generated from 20 Hz. In comparison to seobnr4phm itself, this amounts to an improvement in computational efficiency by 2 orders of magnitude. Utilizing additional graphics processing units (GPU) acceleration, we find that this speedup can be increased further with the generation of batches of waveforms simultaneously. Even without additional GPU acceleration, this dramatic decrease in waveform generation cost can reduce the inference timescale from weeks to hours.

When the expansion of the Universe is dominated by a perfect fluid with equation of state parameter $w$ and a sound speed $c_s$ satisfying $w=c_s^2\le 1$, the Hubble parameter $H$ and time $t$ satisfy the bound $Ht\ge 1/3$. There has been recent interest in “ultraslow” expansion laws with $Ht<1/3$ (sometimes described as “fast expanding” models). We examine various models that can produce ultraslow expansion: scalar fields with negative potentials, barotropic fluids, braneworld models, or a loitering phase in the early Universe. Scalar field models and barotropic models for ultraslow expansion are unstable to evolution toward $w=1$ or $w\to \infty$ in the former case and $w\to \infty$ in the latter case. Braneworld models can yield ultraslow expansion but require an expansion law beyond the standard Friedman equation. Loitering early universe models can produce a quasistatic expansion phase in the early Universe but require an exotic negative-density component. These results suggest that appeals to an ultraslow expansion phase in the early Universe should be approached with some caution, although the loitering early universe may be worthy of further investigation. These results do not apply to ultraslow contracting models.

An internally thermalized dark matter (DM) with only gravitational interaction with the standard model (SM) particles at low temperatures, may undergo number-changing self-scatterings in the early Universe, eventually freezing out to the observed DM abundance. If these reactions, such as a $3\to 2$ process, take place when the DM is nonrelativistic, DM cannibalizes itself to cool much slower than standard nonrelativistic matter during the cannibal phase. As shown in earlier studies, if the cannibal phase takes place during the matter-dominated epoch, there are very strong constraints from structure formation. Considering scenarios in which the cannibal phase freezes out in the radiation-dominated epoch instead, we show that cannibal DM decoupled from the SM can be viable, consistent with all present cosmological constraints. To this end, we solve the coupled evolution equations of the DM temperature and density, and determine its abundance for different DM self-couplings. We then evaluate the constraints on these parameters from the cosmic-microwave background power spectrum, the big-bang nucleosynthesis limits on the relativistic degrees of freedom, the Lyman-$\alpha$ limits on the DM free-streaming length and the theoretical upper bound on the $3\to 2$ annihilation rate from $S-\mathrm{matrix}$ unitarity. We find that depending upon the DM self-couplings, a scalar cannibal DM with mass in the range of around 80 eV to 700 TeV can make up the observed DM density and satisfy all the constraints, when the initial DM temperature ($T_{\mathrm{DM}}$) is lower than the SM one ($T_{\mathrm{SM}}$), with $T_{\mathrm{SM}}/9100\lesssim T_{\mathrm{DM}}\lesssim T_{\mathrm{SM}}/1.1$.

We reexamine sterile neutrino dark matter in gauged $U(1{)}_{B-L}$ model. Improvements have been made by tracing and careful evaluation of the evolution of the number densities of sterile neutrinos $N$ and extra neutral gauge bosons $Z^{\prime }$. As a result, the cosmologically-interesting gauge coupling of $U(1{)}_{B-L}$ for freeze-in sterile neutrinos turns out to be smaller than the values reported in the literature. This avoids the overproduction of $Z^{\prime }$ so that it is consistent with the big bang nucleosynthesis and the cosmic microwave background constraints on the effective number of neutrino species. Similarly, the free-streaming length constraints exclude a large parameter space derived in previous studies. In addition to known freeze-in pair production of $N$ from the standard model fermion pairs, we find the case that $N$ is dominantly produced from a pair of $Z^{\prime }$ at the temperature characterized by the $B-L$ breaking scalar mass. Thus, the naive truncation of the $U(1{)}_{B-L}$ scalar contribution made in the literature is not valid.

We perform a dynamical system analysis of Myrzakulov or $F(R,T)$ gravity, which is a subclass of affinely connected metric theories, where ones uses a specific but nonspecial connection that allows for nonzero curvature and torsion simultaneously. We consider two classes of models, extract the critical points, and examine their stability properties alongside their physical features. In the class 1 models, which possess $\mathrm{\Lambda }$ cold dark matter (CDM) cosmology as a limit, we find the sequence of matter and dark energy eras, and we show that the Universe will result in a dark-energy-dominated critical point for which dark energy behaves like a cosmological constant. Concerning the dark energy equation-of-state parameter, we find that it lies in the quintessence or phantom regime, according to the value of the model parameter. For the class 2 models, we again find the dark-energy-dominated, de Sitter late-time attractor, although the scenario does not possess $\mathrm{\Lambda }\mathrm{CDM}$ cosmology as a limit. The cosmological behavior is richer, and the dark energy sector can be quintessencelike, phantomlike, or experience the phantom-divide crossing during the evolution.

We present a search for continuous gravitational-wave signals from an unidentified pulsar potentially powering HESS J1427-608, a spatially unresolved TeV point source detected by the High Energy Stereoscopic System (HESS). The search uses a semicoherent algorithm, which combines the maximum likelihood $\mathcal{F}$ statistic with a hidden Markov model to efficiently detect and track quasimonochromatic signals that wander randomly in frequency. It uses data from the second observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory. Multiwavelength observations of the HESS source are combined with the proprieties of the population of TeV-bright pulsar wind nebulae to constrain the search parameters. We find no evidence of gravitational-wave emission from this target. We set upper limits on the characteristic wave strain $h_0^{95\%}$ (for circularly polarized signals) at 95% confidence level in sample subbands and interpolate it to estimate the sensitivity in the full band. We find $h_0^{95\%}=1.3\times {10}^{-25}$ near 185 Hz. The implied constraints on the ellipticity and $r$-mode amplitude reach $\epsilon \le {10}^{-5}$ and $\alpha \le {10}^{-3}$ at 200 Hz, respectively.

In the next decade, the Laser Interferometer Space Antenna (LISA) will detect the coalescence of massive black hole binaries (MBHBs) in the range $[{10}^4,{10}^8]{\mathrm{M}}_{\odot }$, up to $z\sim 10$. Their gravitational wave (GW) signal is expected to be accompanied by an electromagnetic counterpart (EMcp), generated by the gas accreting on the binary or on the remnant BH. In this work, we present the number and characteristics (such as redshift and mass distribution, apparent magnitudes or fluxes) of EMcps detectable jointly by LISA and some representative EM telescopes. We combine state-of-the-art astrophysical models for the galaxies formation and evolution to build the MBHBs catalogs, with Bayesian tools to estimate the binary sky position uncertainty from the GW signal. Exploiting additional information from the astrophysical models, such as the amount of accreted gas and the BH spins, we evaluate the expected EM emission in the soft x-ray, optical and radio bands. Overall, we predict between 7 and 20 EMcps in 4 yrs of joint observations by LISA and the considered EM facilities, depending on the astrophysical model. We also explore the impact of the hydrogen and dust obscuration of the optical and x-ray emissions, as well as of the collimation of the radio emission: these effects reduce the number to EMcps to 2 or 3, depending on the astrophysical model, again in 4 yrs of observations. Most of the EMcps are characterized by faint EM emission, challenging the observational capabilities of future telescopes. Finally, we also find that systems with multimodal sky position posterior distributions represent only a minority of cases and do not affect significantly the number of EMcps.

We revisit the detection of luminous dark matter in direct detection experiments. In this scenario, dark matter scatters endothermically to produce an excited state, which decays to produce a photon. We explore ways in which the electron recoil signal from the decay photon can be differentiated from other potential electron recoil signals with a narrow spectral shape. We find that larger volume/exposure xenon detectors will be unable to differentiate the signal origin without significant improvements in detector energy resolution of around an order of magnitude. We also explore what can be learned about a generic luminous dark matter signal with a higher resolution detector. Motivated by the advancements in energy resolution by solid-state detectors, we find that sub-eV resolution enables the discovery of LDM in the presence of background levels that would otherwise make observation impossible. We also find that sub-eV resolution can be used to determine the shape of the luminous dark matter decay spectrum and thus constrain the dark matter mass and velocity distribution.

Cosmic-ray (CR) diffusion is the result of the interaction of such charged particles against magnetic fluctuations. These fluctuations originate from large-scale turbulence cascading toward smaller spatial scales, decomposed into three different modes, as described by magnetohydrodynamics (MHD) theory. As a consequence, the description of particle diffusion strongly depends on the model describing the injected turbulence. Moreover, the amount of energy assigned to each of the three modes is, in general, not equally divided, which implies that diffusion properties might be different from one region to another. Here, motivated by the detection of different MHD modes inside the Cygnus-X star-forming region, we study the 3D transport of CRs injected by two prominent sources within a two-zone model that represents the distribution of the modes. Then, by convolving the propagated CR distribution with the neutral gas, we are able to explain the $\gamma$-ray diffuse emission in the region, observed by the Fermi-LAT and HAWC Collaborations. Such a result represents an important step in the long-standing problem of connecting the CR observables with the microphysics of particle transport.

We developed the spacetime-covariant Hamilton principle for barotropic flows of a perfect fluid in the external axial-vector potential conjugate to the helicity current. Such flows carry helicity, a chiral imbalance, controlled by the axial potential. The interest in such a setting is motivated by the recent observation that the axial-current anomaly of quantum field theories with Dirac fermions appears as a kinematic property of classical hydrodynamics. Especially interesting effects occur under the simultaneous actions of the electromagnetic field and the axial-vector potential. With the help of the Hamilton principle, we obtain the extension of the Euler equations by the axial potential and derive anomalies in the divergence of the axial and vector current. Our approach provides a hydrodynamic expression for vector and axial currents and lays down a platform for studying flows with a chiral imbalance and their anomalies.

We study the pair production of the long-lived mediator particles from the decay of the standard model Higgs boson and their subsequent decay into standard model particles. We compute the projected sensitivity, both model independently and with a minimal model, of using the muon spectrometer of the CMS detector at the HL-LHC experiment for ggF, VBF, and VH production modes of the Higgs boson and various decay modes of the mediator particle, along with dedicated detectors for long-lived particle searches like CODEX-b and MATHUSLA. Subsequently, we study the improvement with the FCC-hh detector at the 100 TeV collider experiment for such long-lived mediators, again focusing on the muon spectrometer. We propose dedicated long-lived particle detector designs for the 100 TeV collider experiment, detector for long-lived particles at high energy of 100 TeV, and study their sensitivities.