We apply the gradient flow on a color-electric two-point function that encodes the heavy quark momentum diffusion coefficient. The simulations are done on fine isotropic lattices in the quenched approximation at $1.5T_c$. The continuum extrapolation is performed at fixed flow time followed by a second extrapolation to zero flow time. Perturbative calculations of this correlation function under Wilson flow are used to enhance the extrapolations of the nonperturbative lattice correlator. The final estimate for the continuum correlator at zero flow time largely agrees with one obtained from a previous study using the multilevel algorithm. We perform a spectral reconstruction based on perturbative model fits to estimate the heavy quark momentum diffusion coefficient. The approach we present here yields high-precision data for the correlator and is also applicable for actions with dynamical fermions.

In this paper we derive the high energy evolution equation in the Gribov-Zwanziger approach for the confinement of quarks and gluons. We demonstrate that the new equation generates an exponential decrease of the scattering amplitude at large impact parameter and resolves the main difficulties of color glass condensate high energy effective theory. Such behavior occurs if the gluon propagator in Gribov-Zwanziger approach does not vanish at small momenta. Solving the nonlinear equation for deep inelastic scattering, we show that the suggested equation leads to a Froissart disc with radius ($R_F$), which increases as $R_F\propto Y=\ln (1/x)$, and with a finite width for the distribution over $|b-R_F|$.

The LHC has released precise measurements of elastic proton-proton scattering that provide a unique constraint on the asymptotic behavior of the scattering amplitude at high energies. Recent reanalyses of part of these data indicate that the central values of some forward quantities would be different than initially observed. We introduce correlation information between the original and the reanalyzed data sets in a way suitable for a global fitting analysis of all data. The careful treatment of correlated errors leads to much less stringent limits on the $\rho$ uncertainty and sets up the stage for describing the forward data using a scattering amplitude dominated by only crossing-even terms. In the light of these correlated data, we determine the parameters of the soft Pomeron from the Regge theory. We use Born-level and eikonalized amplitudes. In the Born-level case, we estimate the contribution of the double Pomeron exchange, while in the latter case we investigate the role of the eikonalization in both the one- and two-channel models. The role of the proton-Pomeron vertex form and of the nearest $t$-channel singularity in the Pomeron trajectory receives particular attention. We discuss the implications of our results and present predictions for the total cross section and the $\rho$ parameter in proton-proton collisions at LHC and cosmic ray energies.

Motivated by the LHCb’s new observation of structures in the $J/\psi$-pair invariant mass spectrum, which could be classified as possible $cc\overline{c}\overline{c}$ tetraquark candidates, we systematically study $0^{+}$ fully-charmed tetraquark states through QCD sum rules. Developing the calculation techniques to fourfold heavy hadronic systems, four different configuration currents with $0^{+}$ are considered, and vacuum condensates up to dimension six are included in the operator product expansion. Finally, the mass values acquired for $0^{+}cc\overline{c}\overline{c}$ tetraquark states agree well with the experimental data of the broad structure, which support that it could be a $0^{+}$ fully-charmed tetraquark state.

We discuss the construction of relational observables in time-reparametrization invariant quantum mechanics, and we argue that their physical interpretation can be understood in terms of conditional probabilities, which are defined from the solutions of the quantum constraint equation in a generalization of the Page-Wootters formalism. In this regard, we show how conditional expectation values of worldline tensor fields are related to quantum averages of suitably defined relational observables. We also comment on how the dynamics of these observables can be related to a notion of quantum reference frames. After presenting the general formalism, we analyze a recollapsing cosmological model, for which we construct unitarily evolving quantum relational observables. We conclude with some remarks about the relevance of these results for the construction and interpretation of diffeomorphism-invariant operators in quantum gravity.

A Simpson-Visser spacetime has two non-negative parameters $a$ and $m$ and its metric is correspond with (i) a Schwarzschild metric for $a=0$ and $m\ne 0$, (ii) a regular black hole metric for $a<2m$, (iii) a one-way traversable wormhole metric for $a=2m$, (vi) a two-way traversable wormhole metric for $a>2m$, and (v) an Ellis-Bronnikov wormhole metric for $a\ne 0$ and $m=0$. The spacetime is one of the most useful spacetimes for the purpose of comprehensively understanding gravitational lensing of light rays reflected by a photon sphere of black holes and wormholes. We have investigated gravitational lensing in the Simpson-Visser spacetime in a strong deflection limit in all the non-negative parameters of $a$ and $m$. In a case of $a=3m$, two photon spheres and an antiphoton sphere at the throat degenerate into a marginally unstable photon sphere. The deflection angle of the light rays reflected by the marginally unstable photon sphere at the throat diverges nonlogarithmically in the strong deflection limit.

Some million type Ia supernovae (SN) will be discovered and monitored during upcoming wide area time domain surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). For cosmological use, accurate redshifts are needed among other characteristics; however the vast majority of the SN will not have spectroscopic redshifts, even for their host galaxies, only photometric redshifts. We assess the redshift systematic control necessary for robust cosmology. Based on the photometric vs true redshift relation generated by machine learning applied to a simulation of 500,000 galaxies as observed with LSST quality, we quantify requirements on systematics in the mean relation and in the outlier fraction and deviance so as not to bias dark energy cosmological inference. Certain redshift ranges are particularly sensitive, motivating spectroscopic followup of SN at $z\lesssim 0.2$ and around $z\approx 0.5–0.6$. Including Nancy Grace Roman Space Telescope near infrared bands in the simulation, we reanalyze the constraints, finding improvements at high redshift but little at the low redshifts where systematics lead to strong cosmology bias. We identify a complete spectroscopic survey of SN host galaxies for $z\lesssim 0.2$ as a highly favored element for robust SN cosmology.

We present a systematic calculation of the charged current semi-inclusive deeply inelastic scattering process at leading order twist-3 level in the parton model. We consider the general form of the negatively charged beam scattering off the polarized target which has spin-1. The calculations are carried out by applying the collinear expansion where multiple gluon scattering is taken into account and gauge links are obtained automatically. We first present the general form of the differential cross section in terms of the structure functions by kinematic analysis and then present the structure functions in terms of the gauge-invariant parton distribution functions up to twist-3 level. Considering the angle modulations and polarizations of the cross section, we calculate the complete azimuthal asymmetries in the charged current semi-inclusive deeply inelastic scattering process. The charge asymmetries are also considered in this paper with the introduction of the definitions of the plus and minus cross sections.

We present a holographic model of QCD with a first order chiral restoration phase transition with chemical potential, $\mu$. The first order behavior follows from allowing a discontinuity in the dual description as the quarks are integrated out below their constituent mass. The model predicts a deconfined yet massive quark phase at intermediate densities ($350\mathrm{MeV}<\mu <500\mathrm{MeV}$), above the nuclear density phase, which has a very stiff equation of state and a speed of sound close to one. We also include a holographic description of a color superconducting condensate in the chirally restored vacuum and study the resulting equation of state. They provides a well behaved first order transition from the deconfined massive quark phase at very high density ($\mu >500\mathrm{MeV}$). We solve the Tolman-Oppenheimer-Volkoff equations with the resulting equations of state and find stable hybrid stars with quark cores. We compute the tidal deformability for these hybrid stars and show they are consistent with LIGO/Virgo data on a neutron star collision. Our holographic model shows that quark matter could be present at the core of such compact stars.

A class of two-dimensional sigma models interpolating between $C{P}^1$ and the $SU(2)$ principal chiral model is discussed. We add the Wess-Zumino-Novikov-Witten term and examine the renormalization group flow of the two coupling constants which characterize the model under consideration. The model flows to the $SU(2)$ Wess-Zumino-Novikov-Witten conformal field theory in the IR limit. There is an ordinary phase in which the model flows from the asymptotically free UV limit of the $C{P}^1$ model coupled to an extra massless degree of freedom. At higher-loop order we find evidence that there is also a phase in which the model can flow from nontrivial fixed points in the UV. A nonperturbative confirmation of these extra fixed points would be desirable.

For a three-dimensional higher-derivative scalar superfield model, and a four-dimensional higher-derivative chiral superfield model, where the higher-derivative operators are described by polynomials of arbitrary degrees, we explicitly calculate the two-loop effective potential.

We analyze in full detail the geometric structure of the covariant phase space (CPS) of any local field theory defined over a space-time with boundary. To this end, we introduce a new frame: the “relative bicomplex framework.” It is the result of merging an extended version of the “relative framework” (initially developed in the context of algebraic topology by R. Bott and L. W. Tu in the 1980s to deal with boundaries) and the variational bicomplex framework (the differential geometric arena for the variational calculus). The relative bicomplex framework is the natural one to deal with field theories with boundary contributions, including corner contributions. In fact, we prove a formal equivalence between the relative version of a theory with boundary and the nonrelative version of the same theory with no boundary. With these tools at hand, we endow the space of solutions of the theory with a (pre)symplectic structure canonically associated with the action and which, in general, has boundary contributions. We also study the symmetries of the theory and construct, for a large group of them, their Noether currents, and charges. Moreover, we completely characterize the arbitrariness (or lack thereof for fiber bundles with contractible fibers) of these constructions. This clarifies many misconceptions about the role of the boundary terms in the CPS description of a field theory. Finally, we provide what we call the CPS-algorithm to construct the aforementioned (pre)symplectic structure and apply it to some relevant examples.

We describe the first numerical Tolman-Oppenheimer-Volkoff solutions of compact objects in entangled relativity, which is an alternative to the framework of general relativity that does not have any additional free parameter. Assuming a simple polytropic equation of state and the conservation of the rest-mass density, we notably show that, for any given density, compact objects are always heavier (up to $\sim 8\%$) in entangled relativity than in general relativity—for any given central density within the usual range of neutron stars’ central densities, or for a given radius of the resulting compact object.

Working directly with a general Hamiltonian for the spacetime metric with the $3+1$ decomposition and keeping only the spatial covariance, we investigate the possibility of reducing the number of degrees of freedom by introducing an auxiliary constraint. The auxiliary constraint is considered as part of the definition of the theory. Through a general Hamiltonian analysis, we find the conditions for the Hamiltonian as well as for the auxiliary constraint, under which the theory propagates two tensorial degrees of freedom only. The class of theories satisfying these conditions can be viewed as a new construction for the type-II minimally modified gravity theories, which propagate the same degrees of freedom of but are not equivalent to general relativity in the vacuum. We also illustrate our formalism by a concrete example and derive the dispersion relation for the gravitational waves, which can be constrained by observations.

Accurate models of gravitational waves from merging binary black holes are crucial for detectors to measure events and extract new science. One important feature that is currently missing from the Simulating eXtreme Spacetimes (SXS) Collaboration’s catalog of waveforms for merging black holes, and other waveform catalogs, is the gravitational memory effect: a persistent, physical change to spacetime that is induced by the passage of transient radiation. We find, however, that by exploiting the Bondi-van der Burg-Metzner-Sachs (BMS) balance laws, which come from the extended BMS transformations, we can correct the strain waveforms in the SXS catalog to include the missing displacement memory. Our results show that these corrected waveforms satisfy the BMS balance laws to a much higher degree of accuracy. Furthermore, we find that these corrected strain waveforms coincide especially well with the waveforms obtained from Cauchy-characteristic extraction (CCE) that already exhibit memory effects. These corrected strain waveforms also evade the transient junk effects that are currently present in CCE waveforms. Last, we make our code for computing these contributions to the BMS balance laws and memory publicly available as a part of the python package sxs, thus enabling anyone to evaluate the expected memory effects and violation of the BMS balance laws.

We study the kinematic characteristics of the loop-induced effects on nonresonant Higgs pair production via gluon fusion in a type-II two Higgs doublet model with heavy vectorlike quarks. First, we performed a comprehensive analysis of the model phenomenology, suggesting an ansatz to satisfy theoretical and experimental constraints. Contrary to the usual expectation, the loop-induced effects can highly enhance the di-Higgs rate if the Higgs sector is extended into the wrong-sign limit (${\kappa }_t=-{\kappa }_b=1$): the total cross section can be about three times as large as the SM expectation. As anomalous Higgs trilinear self-coupling of ${\lambda }_{hhh}/{\lambda }_{hhh}^{\mathrm{SM}}=-0.5$, 5.5 similarly enhances the di-Higgs rate, we made a comparative study focusing on the kinematic distributions. The threshold effects from the vectorlike quarks generate the correlated bumps in the distributions of the invariant mass of the Higgs boson pair and the transverse momentum of a Higgs boson, located at $M_{hh}\simeq 2M_{\mathrm{VLQ}}$ and $p_T^h\simeq M_{\mathrm{VLQ}}$. Each bump has a long tail stretching toward the high region. The anomalous ${\lambda }_{hhh}$ cases shift the distributions into low regions. In addition, we show the kinematic difference between the loop-induced effects and an $s$-channel wide resonance. Therefore, the kinematic regimes with high $M_{hh}$ and high $p_T^h$ would have high potential to probe the loop-induced effects on the di-Higgs process, which is shown through full HL-LHC simulations in the $b\overline{b}b\overline{b}$ and $b\overline{b}\gamma \gamma$ final states.

We analyze the prospects for using gravitational waves produced in early universe phase transitions as a complementary probe of the flavor anomalies in $B$ meson decays. We focus on the left-right SU(4) model, for which the strength of the observed lepton universality violation and consistency with other experiments impose a vast hierarchy between the symmetry breaking scales. This leads to a multipeaked gravitational wave signature within the reach of upcoming gravitational wave detectors.

Motivated by recent anomalies in flavor changing neutral current $b\to s{\ell }^{+}{\ell }^{-}$ transitions, we study ${\mathcal{B}}_1\to {\mathcal{B}}_2{\ell }^{+}{\ell }^{-}(\ell =e,\mu ,\tau )$ semileptonic weak decays with the SU(3) flavor symmetry, where ${\mathcal{B}}_{1,2}$ are the spin-$\frac{1}{2}$ baryons of single bottomed antitriplet $T_{b3}$, single charmed antitriplet $T_{c3}$, or light baryons octet $T_8$. Using the SU(3) irreducible representation approach, we first obtain the amplitude relations among different decay modes and then predict the relevant not-yet measured observables of $T_{b3}\to T_8{\ell }^{+}{\ell }^{-}$, $T_{c3}\to T_8{\ell }^{+}{\ell }^{-}$, and $T_8\to T_8^{\prime }{\ell }^{+}{\ell }^{-}$ decays. (a) We calculate the branching ratios of the $T_{b3}\to T_8{\mu }^{+}{\mu }^{-}$ and $T_{b3}\to T_8{\tau }^{+}{\tau }^{-}$ decay modes in the whole $q^2$ region and in the different $q^2$ bins by the measurement of ${\mathrm{\Lambda }}_b^0\to {\mathrm{\Lambda }}^0{\mu }^{+}{\mu }^{-}$. Many of them are obtained for the first time. In addition, the longitudinal polarization fractions and the leptonic forward-backward asymmetries of all $T_{b3}\to T_8{\ell }^{+}{\ell }^{-}$ decays are very similar to each other in certain $q^2$ bins due to the SU(3) flavor symmetry. (b) We analyze the upper limits of $\mathcal{B}(T_{c3}\to T_8{\ell }^{+}{\ell }^{-})$ by using the experimental upper limits of $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to p{\mu }^{+}{\mu }^{-})$ and $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to p{e}^{+}{e}^{-})$, and find the experimental upper limit of $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to p{\mu }^{+}{\mu }^{-})$ giving the effective bounds on the relevant SU(3) flavor symmetry parameters. The predictions of $\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^0{e}^{+}{e}^{-})$ and $\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^0{\mu }^{+}{\mu }^{-})$ will be different between the single-quark transition dominant contributions and the $W$-exchange dominant ones. (c) As for $T_8\to T_8^{\prime }{\ell }^{+}{\ell }^{-}$ decays, we analyze the single-quark transition contributions and the $W$-exchange contributions by using the two experimental measurements of $\mathcal{B}({\mathrm{\Xi }}^0\to {\mathrm{\Lambda }}^0{e}^{+}{e}^{-})$ and $\mathcal{B}({\mathrm{\Sigma }}^{+}\to p{\mu }^{+}{\mu }^{-})$, and give the branching ratio predictions by assuming either single-quark transition dominant contributions or the $W$-exchange dominant contributions. According to our predictions, some observables are accessible to the experiments at BESIII, LHCb and Belle-II.