We propose that a significant positive deviation from $1/3$ for the spin density matrix element ${\rho }_{00}$ of the $\varphi$ meson may indicate the existence of a mean field of the $\varphi$ meson generated in heavy-ion collisions. This explains why STAR preliminary data for the $\varphi$ meson’s ${\rho }_{00}$ are much larger than $1/3$, while the data of $\mathrm{\Lambda }$ and $\overline{\mathrm{\Lambda }}$ polarization seem not to allow such a significant and positive deviation. The contribution is from the polarization of the strange quark and antiquark through the spin-orbit interaction in the $\varphi$ field, a similar interaction that is responsible for nuclear shell structure at the nucleon level. We show that ${\rho }_{00}$ for the $\varphi$ meson is a good analyzer for fields even if they may strongly fluctuate in space-time.

Many scenarios of new physics predict the existence of neutrino nonstandard interactions, new vector contact interactions between neutrinos, and first generation fermions beyond the Standard Model. We obtain model-independent constraints on the Standard Model effective field theory at high energies from bounds on neutrino nonstandard interactions derived at low energies. Our analysis explores a large set of new physics scenarios and includes full one-loop running effects below and above the electroweak scale. Our results show that neutrino nonstandard interactions already push the scale of new physics beyond the TeV. We also conclude that bounds derived by other experimental probes, in particular by low-energy precision measurements and by charged lepton flavor violation searches, are generally more stringent. Our study constitutes a first step toward the systematization of phenomenological analyses to evaluate the impact of neutrino nonstandard interactions for new physics scenarios at high energies.

We present the calculation of the $K_{l3}$ form factors with $N_f=2+1$ nonperturbatively $O(a)$-improved Wilson quark action and Iwasaki gauge action at the physical point on a large volume of $(10.9\mathrm{fm}{)}^3$ at one lattice spacing of $a=0.085\mathrm{fm}$. We extract the form factors from 3-point functions with three different time separations between the source and sink operators to confirm suppression of excited state contributions. The form factors are calculated in very close to the zero momentum transfer, $q^2=0$, thanks to the large volume, so that stable interpolations to $q^2=0$ are carried out. Using our form factors, we obtain the form factor at $q^2=0$, $f_{+}(0)=0.9603(16)({}_{-4}^{+14})(44)(19)(1)$, where the first, second, and fifth errors are statistical, systematic errors from fit functions and the isospin breaking effect, respectively. The third and fourth errors denote the finite lattice spacing effects estimated from the renormalization factor and contribution beyond the leading order SU(3) chiral perturbation theory. The result of $f_{+}(0)$ yields the Cabibbo-Kobayashi-Maskawa (CKM) matrix element, $|V_{us}|=0.2255(13)(4)$, where the first error comes from our calculation and the second from the experiment. This value is consistent with the ones determined from the unitarity of the CKM matrix and the $K_{l2}$ decay within one standard deviation, while it is slightly larger than recent lattice calculations by at most $1.5\sigma$. Furthermore, we evaluate the shape of the form factors and the phase space integral from our results. We confirm that those results are consistent with the experiment, and also $|V_{us}|$ determined with our phase space integral agrees with the one in the above.

We determine the mass spectra of heavy baryons containing one or more bottom quarks along with their hyperfine splittings and various mass differences on MILC $2+1$ Asqtad lattices at three different lattice spacings. NRQCD action is used for bottom quarks whereas relativistic HISQ action for the lighter up/down, strange, and charm quarks. We consider all possible combinations of bottom and lighter quarks to construct the bottom baryon operators for the states $J^P=1/2^{+}$ and $3/2^{+}$.

Dijet azimuthal angle correlation is arguably one of the most direct probes of the medium-induced broadening effects. The evidence for such broadening, however, is not yet clearly observed within the precision of current midrapidity measurements at RHIC and the LHC. We show that the dijet correlation in forward rapidity from the future LHC RUN3, aided by forward detector upgrades, can reveal this broadening thanks to the steeper jet spectra, suppressed vacuum radiations and lower underlying event background, with a sensitivity comparable to that of the future high-luminosity $\mathrm{Au}+\mathrm{Au}$ run at RHIC. Dijet correlation measurements at the two facilities together can provide powerful constraints on the temperature dependence of medium transport properties.

We study the spectrum of the isoscalar pentaquark $udsc\overline{c}$, of either positive or negative parity, in a constituent quark model with linear confinement and a flavor-spin hyperfine interaction previously extended to SU(4) and used to describe the spectrum of the $uudc\overline{c}$ pentaquarks observed at LHCb in 2019. For positive parity we make a distinction between the case where one unit of angular momentum is located in the subsystem of four quarks and the case where the angular momentum is located in the relative motion between a ground-state four-quark subsystem and the antiquark. The novelty is that we introduce the coupling between different flavor states, due to the breaking of exact SU(4)-flavor symmetry of the Hamiltonian model, both for positive- and negative-parity states. An important consequence is that the lowest state, located at 4404 MeV, has quantum numbers $J^P=1/2^{-}$ while without coupling the lowest state has $J^P=1/2^{+}$ or $3/2^{+}$.

The phenomenon of neutrino flavor oscillations motivates searches for sterile neutrinos in a broad range of masses and mixing-parameter values. A sterile neutrino $N$ that mixes predominantly with the $\tau$ neutrino is particularly challenging experimentally. To address this challenge, we propose a new method to search for a ${\nu }_{\tau }$-mixing $N$ that is lighter than the $\tau$ lepton. The method uses the large $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}$ samples collected at $B$-factory experiments to produce the $N$ in $\tau$-lepton decays. We exploit the long lifetime of a sterile neutrino in this mass range to suppress background and apply kinematic and vertexing constraints that enable measuring the sterile-neutrino mass. Estimates for the sensitivities of the BABAR, Belle, and Belle II experiments are calculated and presented.

We propose to detect the interference effect between the atmospheric-scale and solar-scale waves of neutrino oscillation, one of the key consequences of the three-generation structure of leptons. In vacuum, we show that there is a natural and general way of decomposing the oscillation amplitude into these two oscillation modes. The nature of the interference is cleanest in the ${\overline{\nu }}_e$ disappearance channel, since it is free from the $CP$ phase $\delta$. We find that the upcoming JUNO experiment offers an ideal setting to observe this interference with more than $4\sigma$ significance, even under conservative assumptions about the systematic uncertainties. Finally, we discuss the relationship between the mass-ordering resolution and the interference effect.

Precise scientific analysis in collider-based particle physics is possible because of complex simulations that connect fundamental theories to observable quantities. The significant computational cost of these programs limits the scope, precision, and accuracy of Standard Model measurements and searches for new phenomena. We therefore introduce Deep neural networks using Classification for Tuning and Reweighting (Dctr), a neural network-based approach to reweight and fit simulations using all kinematic and flavor information—the full phase space. Dctr can perform tasks that are currently not possible with existing methods, such as implementing uncertainties on nonperturbative models without rerunning the simulation. The core idea behind the new approach is to exploit powerful high-dimensional classifiers to reweight phase space as well as to identify the best parameters for describing data. Numerical examples from $e^{+}{e}^{-}\to \text{jets}$ demonstrate the fidelity of these methods for simulation parameters that have a big and broad impact on phase space as well as those that have a minimal and/or localized impact. The high fidelity of the full phase-space reweighting enables a new paradigm for simulations, parameter tuning, and model systematic uncertainties across particle physics and possibly beyond.

We report the measurement of $e^{+}{e}^{-}\to D_s^{+}{D}_{s2}^{*}(2573{)}^{-}+\mathrm{c}.\mathrm{c}.$ via initial-state radiation using a data sample of an integrated luminosity of $921.9{\mathrm{fb}}^{-1}$ collected with the Belle detector at the $\mathrm{\Upsilon }(4S)$ and nearby. We find evidence for an enhancement with a $3.4\sigma$ significance in the invariant mass of $D_s^{+}{D}_{s2}^{*}(2573{)}^{-}+\mathrm{c}.\mathrm{c}.$ The measured mass and width are $({4619.8}_{-8.0}^{+8.9}(\mathrm{stat}.)\pm 2.3(\mathrm{syst}.))\mathrm{MeV}/c^2$ and $({47.0}_{-14.8}^{+31.3}(\mathrm{stat}.)\pm 4.6(\mathrm{syst}.))\mathrm{MeV}$, respectively. The mass, width, and quantum numbers of this enhancement are consistent with the charmoniumlike state at $4626\mathrm{MeV}/c^2$ recently reported by Belle in $e^{+}{e}^{-}\to D_s^{+}{D}_{s1}(2536{)}^{-}+\mathrm{c}.\mathrm{c}.$ The product of the $e^{+}{e}^{-}\to D_s^{+}{D}_{s2}^{*}(2573{)}^{-}+\mathrm{c}.\mathrm{c}.$ cross section and the branching fraction of $D_{s2}^{*}(2573{)}^{-}\to {\overline{D}}^0{K}^{-}$ is measured from $D_s^{+}{D}_{s2}^{*}(2573{)}^{-}$ threshold to 5.6 GeV.

The surface/state correspondence suggests that the bulk codimensional two surface could be dual to the quantum state in the holographic conformal field theory (CFT). Inspired by the cutoff-anti–de Sitter (AdS)/$T\overline{T}$-deformed-CFT correspondence, we propose that the quantum states of the two-dimensional $T\overline{T}$-deformed holographic CFT are dual to some particular surfaces in the ${\mathrm{AdS}}_3$ gravity. In particular, the time slice of the cutoff surface is dual to the ground state of the $T\overline{T}$-deformed CFT. We examine our proposal by studying the entanglement entropy and complexity. We find that the complexity of the ground state in the deformed theory is consistent with the one of a particular cMERA and the holographic complexity via CV or CA prescription.

We investigate critical phenomena of the Yang-Mills (YM) type one-dimensional matrix model that is a large-$N$ reduction (or dimensional reduction) of the $D+1$ dimensional $U(N)$ pure YM theory (bosonic Banks-Fischler-Shenker-Susskind model). This model shows a large-$N$ phase transition at finite temperature, which is analogous to the confinement/deconfinement transition of the original YM theory. We study the matrix model at a three-loop calculation via the “principle of minimum sensitivity” and find that there is a critical dimension $D=35.5$: At $D\le 35$, the transition is of first order, while it is of second order at $D\ge 36$. Furthermore, we evaluate several observables in our method, and they nicely reproduce the existing Monte Carlo results. Through the gauge/gravity correspondence, the transition is expected to be related to a Gregory-Laflamme transition in gravity, and we argue that the existence of the critical dimension is qualitatively consistent with it. Besides, in the first order transition case, a stable phase having negative specific heat appears in the microcanonical ensemble, which is similar to Schwarzschild black holes. We study some properties of this phase.

We study how to compute the operator product expansion coefficients in the exact renormalization group formalism. After discussing possible strategies, we consider some examples explicitly, within the $\epsilon$ expansions, for the Wilson-Fisher fixed points of the real scalar theory in $d=4-\epsilon$ dimensions and the Lee-Yang model in $d=6-\epsilon$ dimensions. Finally we discuss how our formalism may be extended beyond perturbation theory.

Static, spherically symmetric black holes and compact objects without an event horizon have unstable (stable) circular orbits of a light called photon (antiphoton) sphere. A Damour-Solodukhin wormhole has been suggested as a simple black hole mimicker and the difference of its metric tensors from a black hole is described by a dimensionless parameter $\lambda$. The wormhole with two flat regions has two photon spheres and an antiphoton sphere for $\lambda <\sqrt{2}/2$ and a photon sphere for $\lambda \ge \sqrt{2}/2$. When the parameter $\lambda$ is $\sqrt{2}/2$, the photon sphere is marginally unstable because of degeneration of the photon spheres and antiphoton sphere. We investigate gravitational lensing by the wormhole in weak and strong gravitational fields. We find that the deflection angle of a light ray reflected by the marginally unstable photon sphere diverges nonlogarithmically in a strong deflection limit for $\lambda =\sqrt{2}/2$, while the deflection angle reflected by the photon sphere diverges logarithmically for $\lambda \ne \sqrt{2}/2$. We extend a strong deflection limit analysis for the nonlogarithmic divergence case. We expect that our method can be applied for gravitational lenses by marginally unstable photon spheres of various compact objects.

Electromagnetic and linear gravitational radiation do not solely propagate on the null cone in $3+1$ dimensions in curved spacetimes, contrary to their well-known behavior in flat spacetime. Their additional propagation inside the null cone is known as the tail effect. A compact body will produce a signal whose tail will interact with its future worldline, thus producing a tail-induced self-force. We present new results for the tail-induced scalar, electromagnetic, and gravitational self-force for a test mass in orbit around a central mass, including effects from the internal structure of that body.

The discovery of gravitational waves (GWs) provides an unprecedented arena to test general relativity, including the gravitational Lorentz invariance violation (gLIV). In the propagation of GWs, a generic gLIV leads to anisotropy, dispersion, and birefringence. GW events constrain the anisotropic birefringence particularly well. Kostelecký and Mewes (2016) performed a preliminary analysis for GW150914. We improve their method and extend the analysis systematically to the whole GW transient catalog, GWTC-1. This is the first global analysis of the spacetime anisotropic Lorentzian structure with a catalog of GWs, where multiple events are crucial in breaking the degeneracy among gLIV parameters. With the absence of abnormal propagation, we obtain new limits on 34 coefficients for gLIV in the nonminimal gravity that surpass previous limits by $\sim {10}^2–{10}^5$.

The discovery of new four-dimensional black hole solutions presents a new approach to understand the Gauss-Bonnet gravity in low dimensions. In this paper, we test the Gauss-Bonnet gravity by studying the phase transition and microstructures for the four-dimensional charged anti–de Sitter black hole. In the extended phase space, where the cosmological constant and the Gauss-Bonnet coupling parameter are treated as thermodynamic variables, we find that the thermodynamic first law and the corresponding Smarr formula are satisfied. Both in the canonical ensemble and grand canonical ensemble, we observe the small-large black hole phase transition, which is similar to the case of the van der Walls fluid. This phase transition can also appear in the neutral black hole system. Furthermore, we construct the Ruppeiner geometry, and find that besides the attractive interaction, the repulsive interaction can also dominate among the microstructures for the small black hole with high temperature in a charged or neutral black hole system. This is quite different from the five-dimensional neutral black hole, for which only dominant attractive interaction can be found. The critical behaviors of the normalized scalar curvature are also examined. These results will shed new light into the characteristic property of four-dimensional Gauss-Bonnet gravity.

The detection and characterization of the stochastic gravitational wave background (SGWB) is one of the main goals of gravitational wave (GW) experiments. The observed SGWB will be the combination of GWs from cosmological (as predicted by many models describing the physics of the early universe) and astrophysical origins, which will arise from the superposition of GWs from unresolved sources whose signal is too faint to be detected. Therefore, it is important to have a proper modeling of the astrophysical SGWB (ASGWB) in order to disentangle the two signals; moreover, this will provide additional information on astrophysical properties of compact objects. Applying the cosmic rulers formalism, we compute the observed ASGWB angular power spectrum, hence using gauge-invariant quantities, accounting for all effects intervening between the source and the observer. These are the so-called projection effects, which include Kaiser, Doppler, and gravitational potentials effect. Our results show that these projection effects are the most important at the largest scales, and they contribute to up to tens of percent of the angular power spectrum amplitude, with the Kaiser term being the largest at all scales. While the exact impact of these results will depend on instrumental and astrophysical details, a precise theoretical modeling of the ASGWB will necessarily need to include all these projection effects.

We show that it is possible to combine an early phase of string gas cosmology which can explain the origin of the observed structures on cosmological scales with a short later period of power law inflation which creates spatial flatness. The resulting model is consistent with the “swampland criteria” and the constraints coming from the Trans-Planckian Censorship Conjecture. Such a construction is not possible using only canonical slow-roll inflation, but it can emerge in the warm inflation scenario or in cold inflation with an exponential potential. The resulting cosmology is nonsingular. We discuss the spectrum of cosmological perturbations resulting in our scenario. On large scales (scales which remain larger than the Hubble radius after the initial string gas phase), the spectrum is determined by the thermal string gas fluctuations set up in the primordial phase, and it is almost scale invariant with a slight red tilt. On small scales, the perturbations produced during the inflationary phase dominate. On these scales, the spectrum is once again nearly scale invariant. There is an intermediate range (scales which enter the Hubble radius during the period of inflation) in which the string gas fluctuations are damped but continue to dominate over those produced during the period of inflation. On these scales, the spectrum has a sharp red spectral index of $n_s-1\sim -2$.

The current paradigm for constructing waveforms from precessing compact binaries is to first construct a waveform in a noninertial, coprecessing binary source frame followed by a time-dependent rotation to map back to the physical, inertial frame. A key insight in the construction of these models is that the coprecessing waveform can be effectively mapped to some equivalent aligned spin waveform. Secondly, the time-dependent rotation implicitly introduces $m$-mode mixing, necessitating an accurate description of higher-order modes in the coprecessing frame. We assess the efficacy of this modeling strategy in the strong field regime using numerical relativity simulations. We find that this framework allows for the highly accurate construction of $(2,\pm 2)$ modes in our dataset, while for higher order modes, especially the $(2,|1|),(3,|2|)$ and $(4,|3|)$ modes, we find rather large mismatches. We also investigate a variant of the approximate map between coprecessing and aligned spin waveforms, where we only identify the slowly varying part of the time domain coprecessing waveforms with the aligned-spin one, but find no significant improvement. Our results indicate that the simple paradigm to construct precessing waveforms does not provide an accurate description of higher order modes in the strong-field regime and demonstrate the necessity for modeling mode asymmetries and mode-mixing to significantly improve the description of precessing higher order modes.