In 2015, the PHENIX Collaboration has measured single-spin asymmetries for charged pions in transversely polarized $p+p$ collisions at the center-of-mass energy of $\sqrt{s}=200\mathrm{GeV}$. The pions were detected at central rapidities of $|\eta |<0.35$. The single-spin asymmetries are consistent with zero for each charge individually, as well as consistent with the previously published neutral-pion asymmetries in the same rapidity range. However, they show a slight indication of charge-dependent differences which may suggest a flavor dependence in the underlying mechanisms that create these asymmetries.

We argue for the quantum-gravitational inconsistency of certain 6D $\mathcal{N}=(1,0)$ supergravity theories, whose anomaly-free gauge algebra $\mathfrak{g}$ and hypermultiplet spectrum $M$ were observed by Raghuram et al. [J. High Energy Phys. 07 (2021) 048] to be realizable only as part of a larger gauge sector $({\mathfrak{g}}^{\prime }\supset \mathfrak{g},M^{\prime }\supset M)$ in F-theory. To detach any reference to a string theoretic method of construction, we utilize flavor symmetries to provide compelling reasons why the vast majority of such $(\mathfrak{g},M)$ theories are not compatible with quantum gravity constraints, and how the “automatic enhancement” to $({\mathfrak{g}}^{\prime },M^{\prime })$ remedies this. In the first class of models, with ${\mathfrak{g}}^{\prime }=\mathfrak{g}\oplus \mathfrak{h}$, we show that there exists an unbroken flavor symmetry $\mathfrak{h}$ acting on the matter $M$, which, if ungauged, would violate the no-global-symmetries hypothesis. This argument also applies to 1-form center symmetries, which govern the gauge group topology and massive states in representations different from those of massless states. In a second class, we find that $\mathfrak{g}$ is incompatible with the flavor symmetry of certain supersymmetric strings that must exist by the completeness hypothesis.

The background-field method is adopted for studying the dynamics of coherent states within an interacting scalar field theory. Focusing on a coherent state that corresponds to the homogeneous condensate, the quantum depletion of the expectation value of the field operator is demonstrated to be due to the annihilation of the condensate constituents into relativistic quanta. Moreover, due to the fact that the initial field acceleration and energy for the nonsqueezed coherent states are determined in terms of a bare coupling constant, instead of the renormalized one, the appearance of perturbative singularities is shown to be inevitable. In other words, consistency of these states requires the finiteness of the bare coupling constant, through the resummation.

Black hole spectroscopy is the proposal to observe multiple quasinormal modes in the ringdown of a binary black hole merger. In addition to the fundamental quadrupolar mode, overtones and higher harmonics may be present and detectable in the gravitational wave signal, allowing for tests of the no-hair theorem. We analyze in detail the strengths and weaknesses of the standard Rayleigh criterion supplied with a Fisher matrix error estimation, and we find that the criterion is useful, but too restrictive. Therefore, we motivate the use of a conservative high Bayes factor threshold to obtain the black hole spectroscopy horizons of current and future detectors; i.e., the distance (averaged in sky location and binary inclination) up to which one or more additional modes can be detected and confidently distinguished from each other. We set up all of our searches for additional modes starting at $t=10(M_1+M_2)$ after the peak amplitude in simulated signals of circular nonspinning binaries. An agnostic multimode analysis allows us to rank the subdominant modes: for nearly equal mass binaries, we find $(\ell ,m,n)=(2,2,1)$ and (3,3,0) and, for very asymmetric binaries, (3,3,0) and (4,4,0), for the secondary and tertiary modes, respectively. At the current estimated rates for heavy stellar mass binary black hole mergers, with primary masses between 45 and 100 solar masses, we expect an event rate of mergers within our conservative estimate for the (2,2,1) spectroscopy horizon of $0.03–0.10{\mathrm{yr}}^{-1}$ for LIGO at design sensitivity and $(0.6-2.4)\times {10}^3{\mathrm{yr}}^{-1}$ for the future third generation ground-based detector Cosmic Explorer.

It has been known for many years that the leading correction to the black hole entropy is a logarithmic term, which is universal and closely related to conformal anomaly. A fully consistent analysis of this issue has to take quantum backreactions to the black hole geometry into account. However, it was always unclear how to naturally derive the modified black hole metric, especially from an effective action, because the problem refers to the elusive nonlocality of quantum gravity. In this paper, we show that this problem can be resolved within an effective field theory (EFT) framework of quantum gravity. Our work suggests that the EFT approach provides a powerful and self-consistent tool for studying the quantum gravitational corrections to black hole geometries and thermodynamics.

The solar gravitational lens (SGL) offers unique capabilities for direct high-resolution imaging of faint, distant objects, such as exoplanets. For that purpose, in the near future, a spacecraft carrying a meter-class telescope with a solar coronagraph would be placed in the focal region of the SGL. That region begins at $\sim 547$ astronomical units from the Sun and occupies the immediate vicinity of the target-specific primary optical axis—the line that connects the center of the target and that of the Sun. Clearly, this axis is not at rest. It undergoes complex motion as the exoplanet orbits its host star, as that star moves with respect to the Sun, and even as the Sun itself moves with respect to the Solar System’s barycenter due to the gravitational pull of planets in our Solar System. Although less prominent, other motions exist. An image of an extended object is projected by the SGL into an image plane and moves within that plane, responding to the motion of the optical axis. To sample the image, a telescope must always be on the move, following the projection, with precise knowledge of its own position with respect to the image. We consider the dominant motions that determine the position of the focal line as a function of time. We evaluate the needed navigational capability for the telescope to conduct a multiyear exoplanet imaging mission in the focal region for the SGL. We show that even in a rather conservative case, when an Earth-like exoplanet is in our immediate stellar neighborhood at $\sim 10$ light years, the motion of the image is characterized by a small total acceleration that is driven primarily by the orbital motion of the exoplanet (its effect on the projected image estimated to be at the level of $\sim 6\mu {\mathrm{m}/\mathrm{s}}^2$, decreasing inversely with distance to a target) and by the reflex motion of our Sun (target independent, contributing at $\sim 0.2\mu {\mathrm{m}/\mathrm{s}}^2$). We discuss how the amplified light of the host star allows us to establish a local reference frame that significantly relaxes navigational requirements for the imaging operations. We conclude that the required navigation in the SGL’s focal region, although complex, can be accurately modeled, and a $\sim 10$-year prospective imaging mission is achievable with the already available propulsion technology.

We revisit a general minisuperspace (MSS) formalism for scalar tensor Friedmann-Lemaître-Robertson-Walker type cosmological models in an arbitrary frame with a perfect fluid source. We discuss how to impose Cauchy data on the corresponding dynamical system in order to reconstruct a standard ($\mathrm{\Lambda }\mathrm{CDM}$) cosmological model. So far, the integrability of such models has been extensively studied in the Einstein or Jordan frames mainly. We extend these studies to an arbitrary frame taking into account nonminimal coupling between matter and gravity. To this aim we explore a gauge freedom associated with a choice of lapse function. We show that particular isothermal MSS coordinates are related with Einstein frames representing solution equivalent classes and have some invariant meaning. This provides a new universal framework for investigating cosmic evolution in an arbitrary frame: analytical solutions obtained in the Einstein frame can be transformed back to the physical frame by making use of a conformal transformation and field redefinition. We also show how such a technique can be useful when applied to Wheeler-DeWitt quantum cosmology.

We consider a spatially flat Friedmann-Lemaître-Robertson-Walker background space with an ideal gas and a multifield Lagrangian consisting of two minimally coupled scalar fields which evolve in a field space of constant curvature. For this cosmological model we classify the potential function for the scalar fields such that variational point symmetries exist. The corresponding conservation laws are calculated. Finally, analytic solutions are presented for specific functional forms of the scalar field potential in which the cosmological field equations are characterized as a Liouville integrable system by point symmetries. The free parameters of the cosmological model are constrained in order to describe analytic solutions for an inflationary epoch. Finally, stability properties of exact closed-form solutions are investigated. These solutions are scaling solutions with important physical properties for the cosmological model.

Recently, a new choice of variables was identified to understand how the quantum group structure appeared in three-dimensional gravity [M. Dupuis, L. Freidel, F. Girelli, A. Osumanu, and J. Rennert, On the origin of the quantum group symmetry in 3d quantum gravity, arXiv:2006.10105]. These variables are introduced via a canonical transformation generated by a boundary term. We show that this boundary term can actually be taken to be the volume of the boundary and that the new variables can be defined in any dimension greater than three. In addition, we study the associated metric and teleparallel formalisms. The former is a variant of the Henneaux-Teitelboim model for unimodular gravity. The latter provides a non-Abelian generalization of the usual Abelian teleparallel formulation.

We present angular diameter measurements obtained by measuring the position of baryon acoustic oscillations (BAO) in an optimized sample of galaxies from the first three years of Dark Energy Survey data (DES Y3). The sample consists of 7 million galaxies distributed over a footprint of $4100{\mathrm{deg}}^2$ with $0.6<z_{\text{photo}}<1.1$ and a typical redshift uncertainty of $0.03(1+z)$. The sample selection is the same as in the BAO measurement with the first year of DES data, but the analysis presented here uses three times the area, extends to higher redshift, and makes a number of improvements, including a fully analytical BAO template, the use of covariances from both theory and simulations, and an extensive preunblinding protocol. We used two different statistics; angular correlation function and power spectrum, and validate our pipeline with an ensemble of over 1500 realistic simulations. Both statistics yield compatible results. We combine the likelihoods derived from angular correlations and spherical harmonics to constrain the ratio of comoving angular diameter distance $D_M$ at the effective redshift of our sample to the sound horizon scale at the drag epoch. We obtain $D_M(z_{\mathrm{eff}}=0.835)/r_{\mathrm{d}}=18.92\pm 0.51$, which is consistent with, but smaller than, the Planck prediction assuming flat $\mathrm{\Lambda }\mathrm{CDM}$, at the level of $2.3\sigma$. The analysis was performed blind and is robust to changes in a number of analysis choices. It represents the most precise BAO distance measurement from imaging data to date, and is competitive with the latest transverse ones from spectroscopic samples at $z>0.75$. When combined with DES $3\mathrm{x}2\mathrm{pt}+\mathrm{SNIa}$, they lead to improvements in $H_0$ and ${\mathrm{\Omega }}_m$ constraints by $\sim 20\%$.

We apply the formalism of dynamical system analysis to investigate the evolution of interacting dark energy scenarios at the background and perturbation levels in a unified way. Since the resulting dynamical system contains the extra perturbation variable related to the matter overdensity, the critical points of the background analysis split, corresponding to different behavior of matter perturbations and hence to stability properties. From the combined analysis, we find critical points that describe the nonaccelerating matter-dominated epoch with the correct growth of matter structure, and the fact that they are saddle provides the natural exit from this phase. Furthermore, we find stable attractors at late times corresponding to a dark energy–dominated accelerated solution with constant matter perturbations, as required by observations. Thus, interacting cosmology can describe the matter and dark energy epochs correctly, both at the background and perturbation levels, which reveals the capabilities of the interaction.

False vacuum decay in quantum mechanical first order phase transitions is a phenomenon with wide implications in cosmology and presents interesting theoretical challenges. In the standard approach, it is assumed that false vacuum decay proceeds through the formation of bubbles that nucleate at random positions in spacetime and subsequently expand. In this paper, we investigate the presence of correlations between bubble nucleation sites using a recently proposed semiclassical stochastic description of vacuum decay. This procedure samples vacuum fluctuations, which are then evolved using classical lattice simulations. We compute the two-point function for bubble nucleation sites from an ensemble of simulations, demonstrating that nucleation sites cluster in a way that is qualitatively similar to peaks in random Gaussian fields. We qualitatively assess the phenomenological implications of bubble clustering in early Universe phase transitions, which include features in the power spectrum of stochastic gravitational waves and an enhancement or suppression of the probability of observing bubble collisions in the eternal inflation scenario.

In the early Universe above the weak scale, both baryon $B$ and lepton $L$ numbers are violated by nonperturabive effects in the Standard Model while $B-L$ remains conserved. Introducing new physics which violates perturbatively $L$ and/or $B$, one can generate dynamically a nonzero $B-L$ charge and hence a nonzero $B$ charge. In this work, we focus on the former scenario, which is also known as leptogenesis. We show how to describe the evolutions of lepton flavor charges taking into account the complete Standard Model lepton flavor and spectator effects in a unified and lepton flavor basis–independent way. The recipe we develop can be applied to any leptogenesis model with arbitrary number of new scalars carrying nonzero hypercharges and is valid for cosmic temperature ranging from ${10}^{15}\mathrm{GeV}$ down to the weak scale. We demonstrate that in order to describe the physics in a basis-independent manner and to include lepton flavor effect consistently it is necessary to describe both left-handed and right-handed lepton charges in terms of density matrices. This is a crucial point since physics should be basis independent. As examples, we apply the formalism to type-I and type-II leptogenesis models where in the latter case a flavor-covariant formalism is indispensable.

Gravitational waves from the coalescence of compact-binary sources are now routinely observed by Earth bound detectors. The most sensitive search algorithms convolve many different precalculated gravitational waveforms with the detector data and look for coincident matches between different detectors. Machine learning is being explored as an alternative approach to building a search algorithm that has the prospect to reduce computational costs and target more complex signals. In this work we construct a two-detector search for gravitational waves from binary black hole mergers using neural networks trained on nonspinning binary black hole data from a single detector. The network is applied to the data from both observatories independently and we check for events coincident in time between the two. This enables the efficient analysis of large quantities of background data by time-shifting the independent detector data. We find that while for a single detector the network retains 91.5% of the sensitivity matched filtering can achieve, this number drops to 83.9% for two observatories. To enable the network to check for signal consistency in the detectors, we then construct a set of simple networks that operate directly on data from both detectors. We find that none of these simple two-detector networks are capable of improving the sensitivity over applying networks individually to the data from the detectors and searching for time coincidences.

Compact binary systems emit gravitational radiation which is potentially detectable by current Earth bound detectors. Extracting these signals from the instruments’ background noise is a complex problem and the computational cost of most current searches depends on the complexity of the source model. Deep learning may be capable of finding signals where current algorithms hit computational limits. Here we restrict our analysis to signals from nonspinning binary black holes and systematically test different strategies by which training data is presented to the networks. To assess the impact of the training strategies, we reanalyze the first published networks and directly compare them to an equivalent matched-filter search. We find that the deep learning algorithms can generalize low signal-to-noise ratio (SNR) signals to high SNR ones but not vice versa. As such, it is not beneficial to provide high SNR signals during training, and fastest convergence is achieved when low SNR samples are provided early on. During testing we found that the networks are sometimes unable to recover any signals when a false alarm probability $<{10}^{-3}$ is required. We resolve this restriction by applying a modification we call unbounded Softmax replacement (USR) after training. With this alteration we find that the machine learning search retains $\ge 91.5\%$ of the sensitivity of the matched-filter search down to a false-alarm rate of 1 per month.

Taking a two interacting scalar toy model with interaction term $g\varphi {\chi }^2$, we study the production of $\chi$ particles coming from the decay of an asymptotic and highly occupied beam of $\varphi$ particles. We perform a nonperturbative analysis coming from parametric resonant instabilities and investigate the possibility that massive $\chi$ particles are produced from decays of massless $\varphi$ particles from the beam. Although this process is not present in a perturbative analysis, our nonperturbative approach allows it to happen under certain conditions. For a momentum $p$ of the beam particles and a mass $m_{\chi }$ of the produced ones, we find that the decay is allowed if the energy density of the beam exceeds the instability threshold $p^2{m}_{\chi }^4/(2g^2)$. We also provide an analytical expression for the spontaneous decay rate at the earliest time.

A search for double-heavy tetraquark state candidates $X_{cc\overline{s}\overline{s}}$ decaying to $D_s^{+}{D}_s^{+}$ and $D_s^{*+}{D}_s^{*+}$ is presented for the first time using the data samples of $102\times {10}^6$ $\mathrm{\Upsilon }(1S)$ and $158\times {10}^6$ $\mathrm{\Upsilon }(2S)$ events, and the data samples at $\sqrt{s}=10.52$, 10.58, and 10.867 GeV corresponding to integrated luminosities of 89.5, 711.0, and $121.4{\mathrm{fb}}^{-1}$, respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. The invariant-mass spectra of the $D_s^{+}{D}_s^{+}$ and $D_s^{*+}{D}_s^{*+}$ are studied to search for possible resonances. No significant signals are observed, and the 90% confidence level upper limits on the product branching fractions [$\mathcal{B}(\mathrm{\Upsilon }(1S,2S)\to X_{cc\overline{s}\overline{s}}+\text{anything})\times \mathcal{B}(X_{cc\overline{s}\overline{s}}\to D_s^{+}{D}_s^{+}(D_s^{*+}{D}_s^{*+}))$] in $\mathrm{\Upsilon }(1S,2S)$ inclusive decays and the product values of Born cross section and branching fraction [$\sigma (e^{+}{e}^{-}\to X_{cc\overline{s}\overline{s}}+\text{anything})\times \mathcal{B}(X_{cc\overline{s}\overline{s}}\to D_s^{+}{D}_s^{+}(D_s^{*+}{D}_s^{*+}))$] in $e^{+}{e}^{-}$ collisions at $\sqrt{s}=10.52$, 10.58, and 10.867 GeV under different assumptions of $X_{cc\overline{s}\overline{s}}$ masses and widths are obtained.

With a distinctive internal structure from all established hadrons, the beauty-charmed baryons ${\mathrm{\Xi }}_{bc}$ can provide us with new points of view to decipher the strong interaction. In this work, we point out that the inclusive ${\mathrm{\Xi }}_{bc}\to {\mathrm{\Xi }}_{cc}^{++}+X$ decay is a golden channel for the experimental discovery of ${\mathrm{\Xi }}_{bc}$ at the LHC. A unique feature of this process is that the ${\mathrm{\Xi }}_{cc}^{++}$ is displaced, which greatly reduces the combinatorial background. A feasibility analysis is performed on the ${\mathrm{\Xi }}_{bc}^{+}$ search, which is expected to have a longer lifetime than ${\mathrm{\Xi }}_{bc}^0$ and thus a better displacement resolution. The ${\mathrm{\Xi }}_{bc}^{+}\to {\mathrm{\Xi }}_{cc}^{++}+X$ branching ratio is calculated within the heavy diquark effective theory. Combining the production rate of ${\mathrm{\Xi }}_{bc}$ and the detection efficiency of ${\mathrm{\Xi }}_{cc}^{++}$, we anticipate that hundreds of signal events will be collected during LHCb Run 3.

We study self-interacting massive scalar field theory in static spacetimes with a bifurcate Killing horizon and a wedge reflection. In this theory the Hartle-Hawking state is defined to have the $N$-point correlation functions obtained by analytically continuing those in the Euclidean theory, whereas the double Kubo-Martin-Schwinger (KMS) state is the pure state invariant under the Killing flow and the wedge reflection which is regular on the bifurcate Killing horizon and reduces to the thermal state at the Hawking temperature in each of the two static regions. We demonstrate in the Schwinger-Keldysh operator formalism of perturbation theory the equivalence between the Hartle-Hawking state and the double KMS state with the Hawking temperature, which was shown before by Jacobson in the path-integral framework.

In this paper, we introduce the post-Minkowskian approximation of energy-momentum-squared gravity (EMSG). This approximation is used to study the gravitational energy flux in the context of EMSG. As an application of our results, we investigate the EMSG effect on the first time derivative of the orbital period of the binary pulsars. Utilizing this post-Keplerian parameter, the free parameter of the EMSG theory, $f_0^{\prime }$, is estimated for six known binary pulsars. Taking the binaries that have the most accurate observations, it turns out that $-6\times {10}^{-37}\mathrm{m}{\mathrm{s}}^2{\mathrm{kg}}^{-1}<f_0^{\prime }<+{10}^{-36}\mathrm{m}{\mathrm{s}}^2{\mathrm{kg}}^{-1}$. This bound is in agreement with the precedent studies.