Polarization holonomy is analytically determined for a class of closed, spherical trajectories of light transiting a black hole in the Kerr metric. The leading order geometric optics approximation admits a closed-form expression of such paths, and sets of source/receiver locations are quantified for a spectrum of black hole angular momenta. A conserved, conformal Yano-Killing scalar is then exploited to determine the evolving polarization. Polarization holonomy, the angle between outgoing and incoming polarizations, is quantified for the spectrum of admissible direct and retrograde trajectories. This offers a means of experimentally measuring gravitational Faraday rotation from a single, stationary position.

Two-field models are introduced in the warm inflation to analyze the primordial non-Gaussianity of gauge-invariant perturbation. With the assumptions of slow-roll approximation, strong dissipation and temperature independence of dissipative coefficients, bispectrum and nonlinearity functions are analytically obtained via the Green’s function method. In our analysis, thermal effects of nonadiabaticity and entropy fluctuations in warm inflation contribute mainly to the non-Gaussianity. The former is characterized by the slow-roll parameter $\beta$, a unique parameter of warm inflation, and the latter is associated with the perturbations of cosmic temperature, interpreted as thermal fluctuations from the thermalized radiation bath. Therefore, compared to the cold inflation model, the non-Gaussianity form of the warm inflation has significantly different physical meanings. Two models with constant and field-dependent dissipative coefficients are introduced, and both confirm that a stronger damping will enhance the non-Gaussianity. From the numerical results, it is still possible to predict an observably large tensor-to-scalar ratio, with amplitude of $r\sim {10}^{-3}–{10}^{-4}$.

We present an enhanced method for the application of Gaussian mixture modeling (GMM) to the coherent WaveBurst (cWB) algorithm in the search for short-duration gravitational wave (GW) transients. The supervised machine learning method of GMM allows for the multidimensional distributions of noise and signal to be modeled over a set of representative attributes, which aids in the classification of GW signals against noise transients (glitches) in the data. We demonstrate that updating the approach to model construction eliminates bias previously seen in the GMM analysis, increasing the robustness and sensitivity of the analysis over a wider range of burst source populations. The enhanced methodology is applied to the generic burst all-sky short search in the LIGO-Virgo full third observing run (O3), marking the first application of GMM to the 3 detector Livingston-Hanford-Virgo network. For both 2- and 3- detector networks, we observe comparable sensitivities to an array of generic signal morphologies, with significant sensitivity improvements to waveforms in the low quality factor parameter space at false alarm rates of 1 per 100 years. This proves that GMM can effectively mitigate blip glitches, which are one of the most problematic sources of noise for unmodeled GW searches. The cWB-GMM search recovers similar numbers of compact binary coalescence (CBC) events as other cWB postproduction methods, and concludes on no new gravitational wave detection after known CBC events are removed.

We systematically investigate tests of the parity $P$ and the combined parity and charge-conjugate $CP$ symmetries from differential angular distributions of $J/\psi$ decaying into the lowest-lying baryon pairs at BESIII and the next-generation super tau-charm facilities (STCFs). Large corrections from $Z$ and $W$ exchange induced parity-violating effects are found for $J/\psi$ decays with large logarithms resummed up to $\mathcal{O}({\alpha }_s)$. The parity-violating asymmetries on the production and the decay sides of $J/\psi$ are both estimated to be of $\mathcal{O}({10}^{-4})$, thus barely observable with the 10 billion $J/\psi$ events currently collected at BESIII. Nevertheless, these asymmetries utilizing the current BESIII data already permit a measurement of the weak mixing angle with an absolute uncertainty $\delta s_w^2\approx 0.09$, corresponding to the first determination of $s_w^2$ at the $J/\psi$ threshold. In the future, STCFs are estimated to improve this bound by a factor of $\sim 20$ to $\delta s_w^2\approx 0.005$ within one year based on luminosity rescaling. We also obtain the 95% confidence level upper bounds on the electric dipole moments of the octet baryons, which are of $\mathcal{O}({10}^{-18})e\mathrm{cm}$ for BESIII and $\mathcal{O}({10}^{-19})e\mathrm{cm}$ for STCFs. These bounds are improved by 2 to 3 orders of magnitude in comparison with the only existing one on $\mathrm{\Lambda }$ from Fermilab. The method discussed in this work also paves a way for a first and direct measurement of the $\mathrm{\Xi }$ and $\mathrm{\Sigma }$ electric dipole moments.

We compute the family of Feynman integrals related to the H graph with unequal masses in relativistic quantum field theory. We present an $ϵ$-factorized differential equation for the 40 master integrals. The alphabet consists of 29 dlog forms with algebraic arguments, involving six square roots. As these square roots are not simultaneously rationalizable, we express the master integrals in terms of iterated integrals. In addition, we express the H graph with unit powers of the propagators up to weight 4 in terms of multiple polylogarithms in compact form.

The $S_8/{\sigma }_8$ tension in the large-scale structure can be explained by decaying dark matter with an almost degenerate spectrum and small enough decay width. Here we propose the Gemini dark matter model, which contains a heavy mother particle ${\chi }_3$ and two twins ${\chi }_{1/2}$, which are almost degenerate in mass and are produced at the same time. The dark sector is charged under the same Froggatt-Nielsen symmetry that can explain the hierarchy of the Standard Model Yukawa couplings. The slightly heavier ${\chi }_2$ decays into ${\chi }_1$ and the axionic component of the flavon, which washes out the small-scale structure and resolves $S_8/{\sigma }_8$ tension. We present the production mechanism of Gemini dark matter and viable parameter regions. We find that, despite the preferred dark matter mass being $\mathcal{O}(1)–\mathcal{O}(100)\mathrm{keV}$, they constitute cold dark matter. The Gemini dark matter model predicts an abundance of dark radiation that will be probed in future measurements of the cosmic microwave background.

Scenarios seeking to address the issue of electroweak symmetry breaking often have heavy colored gauge bosons coupling preferentially to the top quark. Considering the bulk Randall-Sundrum as a typical example, we consider the prospects of the first Kaluza-Klein mode ($G^{(1)}$) of the gluon being produced at the LHC in association with a $t\overline{t}$ pair. The enhanced coupling not only dictates that the dominant decay mode would be to a $t\overline{t}$ pair, but also to a very large $G^{(1)}$ width, necessitating the use of a renormalized $G^{(1)}$ propagator. This, along with the presence of large backgrounds (specially $t\overline{t}jj$), renders a conventional cut-based analysis ineffective, yielding only marginal significances of only around $2\sigma$. The use of machine learning (ML) techniques alleviates this problem to a great extent. In particular, the use of artificial neural networks helps us identify the most discriminating observables, thereby allowing a significance in excess of $4\sigma$ for $G^{(1)}$ masses of $\sim 4\mathrm{TeV}$.

The so-called metastability bound asserts that an unnaturally small Higgs mass is a necessary condition for electroweak vacuum metastability, offering a new approach toward solving the hierarchy problem. So far, this result relies on the assumption of a negative Higgs mass parameter, or equivalently, on electroweak spontaneous symmetry breaking. We derive a new, corresponding bound for the case of a positive mass parameter. When the new bound is significantly more restrictive than or comparable to its established counterpart, it may offer an explanation for the sign of the Higgs mass parameter, and thus, spontaneous symmetry breaking itself. New physics at scales $\mathcal{O}(1–10)\mathrm{TeV}$ can lower these bounds as far as the TeV scale. As an illustration, we consider vacuum stability in the presence of additional TeV-scale fermions with Yukawa couplings to the Higgs, as well as a dimension-six term parametrizing new physics in the UV. This scenario requires new physics that couples strongly to the Higgs, and can potentially be probed at future colliders. Finally, to allow for comparison with concrete mechanisms predicting metastability, we provide the mass-dependent lifetime of the electroweak vacuum for this model.

Millicharged dark matter particles can be efficiently captured by the Sun, where they annihilate into tau leptons, leading to the production of high-energy neutrinos. In contrast to the Earth, the high temperature of the Sun suppresses the fraction of millicharged particles that are bound to nuclei, allowing for potentially high annihilation rates. We recast existing constraints from the IceCube Neutrino Observatory and use this information to place new limits on the fraction of the dark matter that is millicharged. This analysis excludes previously unexplored parameter space for masses of $m_{\chi }\sim (5–100)\mathrm{GeV}$, charges of $q_{\chi }\sim {10}^{-3}–{10}^{-2}$, and fractional abundances as small as $f_{\mathrm{DM}}\sim {10}^{-5}$.

We show that, if there are conserved flavor symmetries, then some properties of a monopole can depend on $\theta$, even when a fermion is massless. The quantized nature of global symmetries and the fractional nature of the Witten effect can lead to interesting structure. Seen from another point of view, aside from possibly breaking baryon and lepton flavor symmetries (the Callan-Rubakov effect), monopole boundary conditions can also break the axial symmetry that otherwise could have been used to remove $\theta$ from the Lagrangian. As an example, in a toy model, we calculate the $\theta$ dependence of the mass of the monopole and properties of the nonzero charge density surrounding the monopole.

We solve a random matrix model for QCD at finite chemical potential, obtained by generalizing the Stephanov model by modifying the random-matrix integration measure with a one-parameter trace deformation. This allows one to check how important the integration measure is for the qualitative features of random matrix models, as well as to test the robustness and universality of the qualitative picture of the original model. While for a small trace deformation the phase diagram is identical to that of the Stephanov model, for a large deformation an exotic phase with spontaneous charge-conjugation breaking appears.

The critical point is one of the most important aspects of the QCD phase diagram of strongly interacting matter. The nonmonotonic behavior of the higher-order moments of conserved quantities like net-baryon ($\mathrm{\Delta }B$), net-charge ($\mathrm{\Delta }Q$), and net-strangeness ($\mathrm{\Delta }S$) are believed to be the signatures of the QCD critical point as a function of energy. We study the effect of the QCD critical point on moments of net-baryon in the Polyakov loop enhanced Nambu-Jona-Lasinio (PNJL) model of QCD with six-quark and eight-quark interactions for finite and infinite volume systems. The study is performed at energies similar to Relativistic Heavy-Ion Collider beam energy scan. Experimentally measuring conserved quantities is difficult due to systematic limitations. Therefore, net-proton, net-pion, and net-kaon are measured as the proxy of $\mathrm{\Delta }B$, $\mathrm{\Delta }Q$, and $\mathrm{\Delta }S$. Recent studies in the subensemble acceptance method on the hadron resonance gas (HRG) model show the dependency of the measured higher-order moment on the experimental acceptance. We applied the subensemble acceptance method to analyze the behavior of $\kappa {\sigma }^2$ of net-baryon distribution within the subvolume system for various acceptance fractions. These results can be directly mapped to the subvolume (particle) percentage of the total volume (conserved quantities). Our findings are compared to the solenoidal tracker at RHIC (STAR) net-proton and proton data with different energies to investigate the presence of the critical point. Additionally, these results are also compared with the ultrarelativistic quantum molecular dynamics (UrQMD), HRG model, and available lattice data.

The inclusive cross section for the production of a single top quark in association with a $W$ boson is measured using $140{\mathrm{fb}}^{-1}$ of proton-proton collision data collected with the ATLAS detector at $\sqrt{s}=13\mathrm{TeV}$. Events containing two charged leptons and at least one jet identified as originating from a $b$-quark are selected. A multivariate discriminant is constructed to separate the $tW$ signal from the $t\overline{t}$ background. The cross section is extracted using a profile likelihood fit to the signal and control regions and it is measured to be ${\sigma }_{tW}=75_{-14}^{+15}\mathrm{pb}$, in good agreement with the Standard Model prediction. The measured cross section is used to extract a value for the left-handed form factor at the $Wtb$ vertex times the Cabibbo-Kobayashi-Maskawa matrix element $|f_{\mathrm{LV}}{V}_{tb}|$ of $0.97\pm 0.10$.

We investigate the Brower-Goddard extension of the Veneziano and Virasoro-Shapiro four-point amplitudes obtained by generalizing the Koba-Nielsen integrals to $d$-dimensional conformally invariant integrals. The amplitudes derived from this framework exhibit polynomial residues and can be shown to adhere to polynomial bounds at high energies. In odd dimensions, the amplitudes decompose into sums of three partial amplitudes, enabling the formulation of general amplitude relations that subsume the Kawai-Lewellen-Tye (KLT) formula as a particular case. The amplitudes contain multiple tachyons in their spectra. Still, we demonstrate that their residues comply with the positivity conditions mandated by unitarity for spacetime dimensions at or below critical values $D_{\mathrm{crit}}(d)$, where $D_{\mathrm{crit}}(6)=26$ and $D_{\mathrm{crit}}(\infty )=10$. In closing, we contemplate physical applications for membranes and potential extensions of the formalism.

Covariant (Lorentz invariant) fracton matter, minimally coupled and charged under a symmetric rank two gauge tensor, is considered. The gauge transformations correspond to linearized longitudinal diffeomorphisms. Consistent possible anomalies are computed using the brst cohomology method. They depend only on the gauge field, treated as a background field, and on the gauge parameter, promoted to an anticommuting scalar ghost field. The problem is phrased in terms of polyforms, whose total degree is the sum of the form degree and of the ghost number. The most general anomaly in two dimensions and in four dimensions is computed, and an anomaly in arbitrary dimensions is individuated. In conclusion, it is shown that a simple higher-derivative scalar field theory is an example of covariant fracton matter.

Within the framework of geometric inflation, where the Friedmann equation is modified to incorporate an infinite series of higher curvature corrections, we describe the emergence of a de Sitter inflationary phase near the poles of an arbitrary dynamical function. Our analysis is quite general and does not depend on any specific choice of cosmological dynamics.

One of the main predictions of general relativity is the existence of black holes featuring a horizon beyond which nothing can escape. Gravitational waves from the remnants of compact binary coalescences have the potential to probe new physics close to the black hole horizons. This prospect is of particular interest given several quantum-gravity models that predict the presence of horizonless and singularity-free compact objects. The membrane paradigm is a generic framework that allows one to parametrize the interior of compact objects in terms of the properties of a fictitious fluid located at the object’s radius. It has been used to derive the quasinormal mode spectrum of static horizonless compact objects. Extending the membrane paradigm to rotating objects is crucial to constrain the properties of the spinning merger remnants. In this work, we extend the membrane paradigm to linear order in spin and use it to analyze the relationships between the quasinormal modes, the object’s reflectivity, and the membrane parameters. We find a breaking of isospectrality between axial and polar modes when the object is partially reflecting or the compactness differs from the black hole case. We also find that in reflective ultracompact objects some of the modes tend toward instability as the spin increases. Finally, we show that the spin enhances the deviations from the black-hole quasinormal mode spectrum as the compactness decreases. This implies that spinning horizonless compact objects may be more easily differentiated than nonspinning ones in the prompt ringdown.

In this paper, we undertake a comprehensive examination of quasinormal modes linked to Lee-Wick black holes, delving into scalar, electromagnetic, and gravitational perturbations using the spectral method. Such black holes can display a rich structure of horizons, and our analysis considers all the representative scenarios, including extremal and nonextremal situations. In particular, we show that purely imaginary quasinormal modes emerge for extremal and near-extremal configurations, suggesting a rapid return to equilibrium without oscillation.

The simplest model of inflation is based around an inflaton field that starts in a coherent false vacuum state with a positive cosmological constant, rolls slowly to the true vacuum and relaxes to it via reheating. We examine whether the scale of the transition from coherence to chaoticity can be examined via the Hanbury-Brown and Twiss (HBT) effect, in parallel with analogous problems of heavy ion physics (the “pion laser” and the thermalizing glasma). We develop an ansatz which contains a definition of “chaoticity” which parallels that of the usual setups where HBT is used. However, we also discuss the differences between the inflationary setup and more mainstream uses of HBT and conclude that these are more significant than the similarities, making the use of the developed methodology uncertain.