We apply the method of QCD sum rules to study the $sq\overline{s}\overline{q}$ tetraquark states with the exotic quantum number $J^{PC}=3^{-+}$, and extract mass of the lowest-lying state to be ${2.33}_{-0.16}^{+0.19}\mathrm{GeV}$. To construct the relevant tetraquark currents we need to explicitly add the covariant derivative operator. Our systematical analysis on their relevant interpolating currents indicates that (a) this state well decays into the $P$-wave $\rho \varphi /\omega \varphi$ channel but not into the $\rho f_2(1525)/\omega f_2(1525)/\varphi f_2(1270)$ channels, and (b) it well decays into the $K^{*}(892){\overline{K}}_2^{*}(1430)$ channel but not into the $P$-wave $K^{*}(892){\overline{K}}^{*}(892)$ channel.

We introduce a novel grooming procedure, which is an extension of the modified MassDrop tagging algorithm, tailored to the needs of deep inelastic scattering (DIS). The new algorithm, which grooms the event as a whole, takes advantage of the natural separation of current and target fragmentation in the Breit frame, in order to eliminate radiation in the beam and central rapidity regions. We study the groomed invariant mass in DIS and within soft-collinear effective theory we construct a factorization theorem for the cross section in the back-to-back limit. In this limit we show that, up to a normalization factor, the cross section does not depend on the incoming hadronic matrix element and we propose this measurement at HERA and the future electron-ion collider (EIC) as a probe to hadronization, precision QCD, and cold nuclear matter effects. We also give an event based definition of the winner-take-all axis and comment on possible applications.

We revisit the calculation of quantum-gravitational corrections to the power spectra of scalar and tensor perturbations in the Born-Oppenheimer approach to quantum gravity. We focus on the issue of the definition of the inner product of the theory and the unitarity of the corrections to the dynamics of the cosmological perturbations. We argue that the correction terms are unitary, provided the inner product is defined in a suitable way, which can be related to a notion of gauge fixing the time variable and the use of conditional probabilities in quantum cosmology. We compare the corrections obtained within this framework to earlier results in the literature and we conclude with some remarks on the physical interpretation of the correction terms.

We study a class of little string theories (LSTs) of A type, described by $N$ parallel M5-branes spread out on a circle and which in the low energy regime engineer supersymmetric gauge theories with $U(N)$ gauge group. The Bogomol’nyi-Prasad-Sommerfield (BPS) states in this setting correspond to M2-branes stretched between the M5-branes. Generalizing an observation made by Ahmed et al. [Bound states of little strings and symmetric orbifold conformal field theories, Phys. Rev. D 96, 081901 (2017).], we provide evidence that the BPS counting functions of special subsectors of the latter exhibit a Hecke structure in the Nekrasov-Shatashvili (NS) limit; i.e., the different orders in an instanton expansion of the supersymmetric gauge theory are related through the action of Hecke operators. We extract $N$ distinct such reduced BPS counting functions from the full free energy of the LST with the help of contour integrals with respect to the gauge parameters of the $U(N)$ gauge group. Physically, the states captured by these functions correspond to configurations where the same number of M2-branes is stretched between some of these neighboring M5-branes, while the remaining M5-branes are collapsed on top of each other and a particular singular contribution is extracted. The Hecke structures suggest that these BPS states form the spectra of symmetric orbifold conformal field theories. We show, furthermore, that to leading instanton order (in the NS limit) the reduced BPS counting functions factorize into simpler building blocks. These building blocks are the expansion coefficients of the free energy for $N=1$ and the expansion of a particular function, which governs the counting of BPS states of a single M5-brane with single M2-branes ending on it on either side. To higher orders in the instanton expansion, we observe new elements appearing in this decomposition whose coefficients are related through a holomorphic anomaly equation.

The $(F1,D2,D8)$ brane configuration with $Li{f}_4^{(2)}\times S^1\times S^5$ geometry is a known Lifshitz vacua supported by massive $B_{\mu \nu }$ field in type IIA theory. This system allows exact IR excitations which couple to massless modes of the fundamental string. Due to these massless modes the solutions have a flow to a dilatonic $Li{f}_4^{(3)}\times S^1\times S^5$ vacua in IR. We study the entanglement entropy on the boundary of this spacetime for the strip and the disk subsystems. To our surprise net entropy density of the excitations at first order is found to be independent of the typical size of subsystems. We interpret our results in light of the first law of entanglement thermodynamics.

Recently, the anomalous decay rate of quasinormal modes has been studied for some geometries under scalar field perturbations, which occurs when the longest-lived modes are the ones with higher angular number, as well as the existence of a critical scalar field mass, i.e., the value of scalar field mass such that the decay rate does not depend appreciably on the angular number, and beyond which the behavior of the decay rate is inverted. Here, we consider the propagation of fermionic fields in the background of Schwarzschild–de Sitter black holes, and we show that the anomalous decay rate behavior and the fine structure, related to the coupling between the chirality and the mass of the field, can be observed in the fermionic spectrum.

The anomalous decay rate of the quasinormal modes occurs when the longest-lived modes are the ones with a higher angular number. Such behavior has been recently studied in different static spacetimes for scalar and fermionic perturbations, being observed in both cases. In this work, we extend the existent studies to the charged spacetimes—namely, the Reissner-Nordström, the Reissner-Nordström de Sitter, and the Reissner-Nordström anti–de Sitter black holes. We show that the anomalous decay rate behavior of the scalar field perturbations is present for every charged geometry in the photon sphere modes, with the existence of a critical scalar field mass whenever $\mathrm{\Lambda }\ge 0$. In general, this critical value of mass increases with the raising of the black hole charge, thus rendering a minimum in the Schwarzschild limit. We also study the dominant mode/family for the massless and massive scalar fields in these geometries, showing a nontrivial dominance of the spectra that depends on the black hole mass and charge.

While cubic quasitopological gravity is unique, there is a family of quartic quasitopological gravities in five dimensions. These theories are defined by leading to a first-order equation on spherically symmetric spacetimes, resembling the structure of the equations of Lovelock theories in higher dimensions, and are also ghost free around anti–de Sitter (AdS). Here we construct slowly rotating black holes in these theories and show that the equations for the off-diagonal components of the metric in the cubic theory are automatically of second order, while imposing this as a restriction on the quartic theories allows to partially remove the degeneracy of these theories, leading to a three-parameter family of Lagrangians of order four in the Riemann tensor. This shows that parallel with Lovelock theory observed on spherical symmetry extends to the realm of slowly rotating solutions. In the quartic case, the equations for the slowly rotating black hole are obtained from a consistent, reduced action principle. These functions admit a simple integration in terms of quadratures. Finally, in order to go beyond the slowly rotating regime, we explore the consistency of the Kerr-Schild Ansatz in cubic quasitopological gravity. Requiring the spacetime to asymptotically match with the rotating black hole in general relativity, for equal oblateness parameters, the Kerr-Schild deformation of an AdS vacuum, does not lead to a solution for generic values of the coupling. This result suggests that in order to have solutions with finite rotation in quasitopological gravity, one must go beyond the Kerr-Schild Ansatz.

A constant early dark energy (EDE) component contributing a fraction $f_{\mathrm{EDE}}(z_c)\sim 10\%$ of the energy density of the universe around $z_c\simeq 3500$ and diluting as or faster than radiation afterwards, can provide a simple resolution to the Hubble tension, the $\sim 5\sigma$ discrepancy—in the $\mathrm{\Lambda }\mathrm{CDM}$ context—between the $H_0$ value derived from early- and late-universe observations. However, it has been pointed out that including Large-Scale Structure (LSS) data, which are in $\sim 3\sigma$ tension with $\mathrm{\Lambda }\mathrm{CDM}$ and EDE cosmologies, might break some parameter degeneracy and alter these conclusions. We reassess the viability of the EDE against a host of high- and low-redshift measurements, by combining LSS observations from recent weak lensing (WL) surveys with CMB, baryon acoustic oscillation (BAO), growth function (FS) and Supernova Ia (SNIa) data. Introducing a model whose only parameter is $f_{\mathrm{EDE}}(z_c)$, we report in agreement with past work a $\sim 2\sigma$ preference for nonzero $f_{\mathrm{EDE}}(z_c)$ from Planck CMB data alone, while the tension with the local $H_0$ measurement from sh0es is reduced below $2\sigma$. Adding BAO, FS and SNIa does not affect this conclusion, while the inclusion of a prior on $H_0$ from sh0es increase the preference for EDE over $\mathrm{\Lambda }\mathrm{CDM}$ to the $\sim 3.6\sigma$ level. After checking the EDE nonlinear matter power spectrum as predicted by standard semi-analytical algorithms via a dedicated set of $N$-body simulations, we test the 1-parameter EDE cosmology against WL data. We find that it does not significantly worsen the fit to the $S_8$ measurement as compared to $\mathrm{\Lambda }\mathrm{CDM}$, and that current WL observations do not exclude the EDE resolution to the Hubble tension. We also caution against the interpretation of constraints obtained from combining statistically inconsistent datasets within the $\mathrm{\Lambda }\mathrm{CDM}$ cosmology. In light of the CMB lensing anomalies, we show that the lensing-marginalized CMB data also favor nonzero $f_{\mathrm{EDE}}(z_c)$ at $\sim 2\sigma$, predicts $H_0$ in $1.4\sigma$ agreement with sh0es and $S_8$ in $1.5\sigma$ and $0.8\sigma$ agreement with kids-viking and des respectively. There still exists however a $\sim 2.5\sigma$ tension with the joint results from kids-viking and des. With an eye on Occam’s razor, we finally discuss promising extensions of the EDE cosmology that could allow us to fully restore cosmological concordance.

The thermal Sunyaev-Zel’dovich (tSZ) effect is a powerful probe of cosmology. The statistical errors in the tSZ power spectrum measurements are dominated by the presence of massive clusters in a survey volume that are easy to identify on an individual cluster basis. First, we study the impact of super sample covariance (SSC) on the tSZ power spectrum measurements, and find that the sample variance is dominated by the connected non-Gaussian (cNG) covariance arising mainly from Poisson number fluctuations of massive clusters in the survey volume. Second, we find that removing such individually detected, massive clusters from the analysis significantly reduces the cNG contribution, thereby causing the SSC to be a leading source of the sample variance. We then show, based on a Fisher analysis, that the power spectrum measured from the remaining diffuse tSZ effects can be used to obtain tight constraints on cosmological parameters as well as the hydrostatic mass bias parameter. Our method allows the use of both individual tSZ cluster counts and the power spectrum measurements of diffuse tSZ signals for cosmology and intracluster gas physics.

We analyze the secular evolution of hierarchical triple systems to second order in the quadrupolar perturbation induced on the inner binary by the distant third body. The Newtonian three-body equations of motion, expanded in powers of the ratio of semimajor axes $a/A$, become a pair of effective one-body Keplerian equations of motion, perturbed by a sequence of multipolar perturbations, denoted quadrupole, $O[(a/A{)}^3]$, octupole, $O[(a/A{)}^4]$, and so on. In the Lagrange planetary equations for the evolution of the instantaneous orbital elements, second-order effects arise from obtaining the first-order solution for each element, consisting of a constant (or slowly varying) piece and an oscillatory perturbative piece, and reinserting it back into the equations to obtain a second-order solution. After an average over the two orbital timescales to obtain long-term evolutions, these second-order quadrupole ($Q^2$) terms would be expected to produce effects of order $(a/A{)}^6$. However we find that the orbital average actually enhances the second-order terms by a factor of the ratio of the outer to the inner orbital periods, $\sim (A/a{)}^{3/2}$. For systems with a low-mass third body, the $Q^2$ effects are small, but for systems with a comparable-mass or very massive third body, such as a Sun-Jupiter system orbiting a solar-mass star, or a $100M_{\odot }$ binary system orbiting a ${10}^6{M}_{\odot }$ massive black hole, the $Q^2$ effects can completely suppress flips of the inner orbit from prograde to retrograde and back that occur in the first-order solutions. These results are in complete agreement with those of Luo, Katz and Dong, derived using a “corrected double averaging” method.

In this paper we discuss the combination of the usual renormalization and factorization scale uncertainties of Higgs-pair production via gluon fusion with the novel uncertainties originating from the scheme and scale choice of the virtual top mass. Moreover, we address the uncertainties related to the top-mass definition for different values of the trilinear Higgs coupling and their combination with the other uncertainties.

The $X(3872)$ resonance has been conjectured to be a $J^{PC}=1^{++}$ charm meson-antimeson two-body molecule. Meanwhile, there is no experimental evidence for larger, few-body compounds of multiple charm meson-antimeson pairs which would resemble larger molecules or nuclei. Here, we investigate such multimeson states to the extent of what can be deduced theoretically from essentials of the interaction between uncharged $D^0$ and $D^{*0}$ mesons. From a molecular $X(3872)$, we predict a $4X$ ($4^{++}$) octamer with a binding energy $B_{4X}>2.08\mathrm{MeV}$, assuming a $D^{*0}{\overline{D}}^0$ system close to the unitary limit [as suggested by the mass of the $X(3872)$]. If we consider heavy-quark spin symmetry explicitly, the $D^{*0}{\overline{D}}^{*0}$ ($2^{++}$) system is close to unitarity, too. In this case, we predict a bound $3X$ ($3^{++}$) hexamer with $B_{3X}>2.29\mathrm{MeV}$ and a more deeply bound $4X$ octamer with $B_{4X}>11.21\mathrm{MeV}$. These results exemplify with hadronic molecules a more general phenomenon of equal-mass two-species Bose systems composed of equal number of either type: the emergence of unbound four- and six-boson clusters in the limit of a short-range two-body interaction which acts only between bosons of different species. Finally, we also study the conditions under which a $2X$ ($2^{++}$) tetramer might form.

The effective-Lagrangian description of Lorentz-invariance violation provided by the so-called Standard Model extension covers all the sectors of the Standard Model, allowing for model-independent studies of high-energy phenomena that might leave traces at relatively low energies. In this context, the quantification of the large set of parameters characterizing Lorentz-violating effects is well motivated. In the present work, effects from the Lorentz-nonconserving Yukawa sector on the electromagnetic moments of charged leptons are calculated, estimated, and discussed. Following a perturbative approach, explicit expressions of leading contributions are derived, and upper bounds on Lorentz violation are estimated from current data on electromagnetic moments. Scenarios regarding the coefficients of Lorentz violation are considered. In a scenario of two-point insertions preserving lepton flavor, the bound on the electron electric dipole moment yields limits as stringent as ${10}^{-27}$, whereas muon and tau-lepton electromagnetic moments determine bounds as restrictive as ${10}^{-14}$ and ${10}^{-5}$, respectively. Another scenario defined by the assumption that Lorentz-violating Yukawa couplings are Hermitian leads to less stringent bounds provided by the muon anomalous magnetic moment, which turn out to be as restrictive as ${10}^{-14}$.

Singlet scalar dark matter can naturally arise in composite Higgs models as an additional stable pseudo-Nambu-Goldstone boson. We study the properties of such a candidate in a model based on $\mathrm{SU}(6)/\mathrm{SO}(6)$, with the light quark masses generated by 4-fermion interactions. The presence of nonlinearities in the couplings allows us to saturate the relic density for masses $400<m_{\mathrm{DM}}<1000\mathrm{GeV}$, and survive the bound from direct detection and indirect detection. The viable parameter regions are in reach of the sensitivities of future upgrades, like XENONnT and LZ.

The LHCb collaboration has recently observed three pentaquark peaks, the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$. They are very close to a pair of heavy baryon-meson thresholds, with the $P_c(4312)$ located 8.9 MeV below the $\overline{D}{\mathrm{\Sigma }}_c$ threshold, and the $P_c(4440)$ and $P_c(4457)$ located 21.8 and 4.8 MeV below the ${\overline{D}}^{*}{\mathrm{\Sigma }}_c$ one. The spin-parities of these three states have not been measured yet. In this work we assume that the $P_c(4312)$ is a $J^P={\frac{1}{2}}^{-}$ $\overline{D}{\mathrm{\Sigma }}_c$ bound state, while the $P_c(4440)$ and $P_c(4457)$ are ${\overline{D}}^{*}{\mathrm{\Sigma }}_c$ bound states of unknown spin-parity, where we notice that the consistent description of the three pentaquarks in the one-boson-exchange model can indeed determine the spin and parities of the later, i.e., of the two ${\overline{D}}^{*}{\mathrm{\Sigma }}_c$ molecular candidates. For this determination we revisit first the one-boson-exchange model, which in its original formulation contains a short-range deltalike contribution in the spin-spin component of the potential. We argue that it is better to remove these deltalike contributions because, in this way, the one-boson-exchange potential will comply with the naïve expectation that the form factors should not have a significant impact in the long-range part of the potential (in particular the one-pion-exchange part). Once this is done, we find that it is possible to consistently describe the three pentaquarks, to the point that the $P_c(4440)$ and $P_c(4457)$ can be predicted from the $P_c(4312)$ within a couple of MeV with respect to their experimental location. In addition the so-constructed one-boson-exchange model predicts the preferred quantum numbers of the $P_c(4440)$ and $P_c(4457)$ molecular pentaquarks to be ${\frac{3}{2}}^{-}$ and ${\frac{1}{2}}^{-}$, respectively.

The polarized strange quark puzzle concerns the fact that the polarized strange quark density extracted from polarized inclusive deep inelastic scattering data is significantly negative, whereas it is zero or slightly positive when extracted from a combined analysis of polarized semi-inclusive and inclusive deep inelastic data. $SU(3)$ flavor symmetry, which, it is generally accepted, is not an exact symmetry, plays an important role in the inclusive analysis, and all the extracted polarized quark densities depend, to some extent, on the level of symmetry breaking introduced. But by far the most sensitive to the breaking is the strange quark density. In this paper we present a NLO QCD analysis of the world data on polarized inclusive DIS data on protons, neutrons and deuterons, including the final JLAB CLAS/EG1b data on the proton and deuteron, and study the sensitivity of the strange quark polarization to the breaking of flavor $SU(3)$.

Here we study two important properties of $2+1$-dimensional QCD—confinement and pseudoscalar glueball spectrum—with holographic approach. We consider the low energy decoupled geometry of the isotropic non-supersymmetric D2 brane. We find the corresponding gauge theory is similar to the $2+1$-dimensional Yang-Mills (YM) theory with the running coupling ${\lambda }^2$. At the extremal limit (i.e., Bogomol’nyi-Prasad-Sommerfield limit), this gauge theory reduces to the super-YM theory. From the Nambu-Goto action of a test string, the potential of a $Q\text{−}\overline{Q}$ pair located on the boundary is calculated. At large $Q\text{−}\overline{Q}$ separation, it gives the tension $\sigma$ of the QCD flux tube. The parametric dependence of $\sigma$ is shown pictorially. It is found that $\sigma$ is a monotonically increasing function of the effective coupling ${\lambda }^2$. In comparison, $\sqrt{\sigma }/g_{\mathrm{YM}}^2{N}_c$ is found to match accurately with the previous results. In the next part, we consider fluctuation of the axion field in the aforementioned gravity background. From the linearized field equation of the fluctuation, we calculate the mass spectrum of $0^{-+}$ numerically using the Wentzel-Kramers-Brillouin approximation. The pseudoscalar mass is found to be related to the string tension approximately as $M_{0^{-+}}/\sqrt{\sigma }\approx 3(n+2)$ for first three energy states, $n=0$, 1, 2.

Binary black holes with spins that are aligned with the orbital angular momentum do not precess. However, post-Newtonian calculations predict that “up-down” binaries, in which the spin of the heavier (lighter) black hole is aligned (antialigned) with the orbital angular momentum, are unstable when the spins are slightly perturbed from perfect alignment. This instability provides a possible mechanism for the formation of precessing binaries in environments where sources are preferentially formed with (anti)aligned spins. In this paper, we present the first full numerical relativity simulations capturing this instability. These simulations span $\sim 100$ orbits and $\sim 3–5$ precession cycles before merger, making them some of the longest numerical relativity simulations to date. Initialized with a small perturbation of 1°–10°, the instability causes a dramatic growth of the spin misalignments, which can reach $\sim 90°$ near merger. We show that this leaves a strong imprint on the subdominant modes of the gravitational wave signal, which can potentially be used to distinguish up-down binaries from other sources. Finally, we show that post-Newtonian and effective-one-body approximants are able to reproduce the unstable dynamics of up-down binaries extracted from numerical relativity.

Regularized Einstein-Gauss-Bonnet theory of gravity in four dimensions is a new attempt to include nontrivial contributions of the Gauss-Bonnet term. In this paper, we make a detailed analysis on possible constraints of the model parameters of the theory from recent cosmological observations and some theoretical constraints, as well. Our results show that the theory with vanishing bare cosmological constant, ${\mathrm{\Lambda }}_0$, is ruled out by the current observational value of $w_{de}$ and the observations of gravitational-wave event GW170817 and the gamma-ray burst (GRB) GRB 170817A, as well. For a nonvanishing bare cosmological constant, instead, our results show that the current observation of the speed of gravitational waves (GWs) measured by GW170817 and GRB 170817A would place a constraint on $\tilde{\alpha }$, a dimensionless parameter of the theory, as $-7.78\times {10}^{-16}\le \tilde{\alpha }\le 3.33\times {10}^{-15}$.