Leptogenesis typically requires the introduction of heavy particles whose out-of-equilibrium decays are essential for generating a matter-antimatter asymmetry, according to one of Sakharov’s conditions. We demonstrate that in Dirac leptogenesis, scatterings between the light degrees of freedom—Standard Model particles plus Dirac neutrinos—are sufficient to generate the asymmetry. The generation requires at least two effective charges conserved by the fast Standard Model interactions. Due to its vanishing source term in the Boltzmann equations, the asymmetry of right-handed neutrinos solely arises through wash-in processes. Sakharov’s conditions are satisfied because the right-handed neutrino partners are out of equilibrium. Consequently, heavy degrees of freedom never needed to be produced in the early universe, allowing for a reheating temperature well below their mass scale. Considering a minimal leptoquark model, we discuss the viable parameter space along with the potential observational signature of an increased number of effective neutrinos in the early universe.

LHC searches have revealed that the Higgs boson decay to a photon pair is nearly consistent with the Standard Model (SM), whereas recently, there is evidence for the decay of the Higgs boson to a $Z$ boson and a photon. These decays are governed by the same set of Wilson coefficients at the tree level in Standard Model effective field theory (SMEFT). In this study, we aim to explain this potential discrepancy between the decays $h\to \gamma \gamma$ and $h\to Z\gamma$. We conduct a model-independent analysis in SMEFT to determine the magnitude and features of the Wilson coefficients required to account for the observed distinction between the two signal strengths. Following this, we adopt a top-down approach, considering all single- and two-field extensions of the SM, including scalars and fermions, as candidates for new interactions. We perform the matching of these models to one loop using automated packages and compare the models’ predictions regarding $h\to Z\gamma$.

We present some lattice QCD results on first (${\chi }_1^i$) and second (${\chi }_2^i$) cumulants of and correlations (${\chi }_{11}^{ij}$) among net baryon-number ($B$), strangeness ($S$) and electric charge ($Q$) along the pseudocritical line [$T_{pc}({\mu }_B)$] in the temperature ($T$)–baryon chemical potential (${\mu }_B$) phase diagram of ($2+1$)-flavor QCD. We point out that violations of sum rules among second order cumulants, which hold in the isospin symmetric limit of vanishing electric charge chemical potential, are small along the $T_{pc}({\mu }_B)$ for the entire range of ${\mu }_B$ covered in the RHIC beam energy scan. For the strangeness neutral matter produced in heavy-ion collisions this leads to a close relation between ${\chi }_{11}^{BS}$ and ${\chi }_{11}^{QS}$. We compare lattice QCD results for ${\chi }_{11}^{BS}/{\chi }_2^S$ along the $T_{pc}({\mu }_B)$ line with preliminary experimental measurements of ${\chi }_{11}^{BS}/{\chi }_2^S$ for collision energies $7.7\mathrm{GeV}\le \sqrt{s_{NN}}\le 62.4\mathrm{GeV}$. While we find good agreements for $\sqrt{s_{NN}}\ge 39\mathrm{GeV}$, differences are sizeable at smaller values of $\sqrt{s_{NN}}$. Moreover, we compare lattice QCD results for the ratio of the strangeness (${\mu }_S$) to baryon (${\mu }_B$) chemical potentials, which define a strangeness neutral system with fixed electric charge to baryon number density, with experimental results obtained by the STAR collaboration for ${\mu }_S/{\mu }_B$ using strange baryon yields on the freeze-out line. Finally, we determine the baryon chemical potential at the freeze-out (${\mu }_B^f$) by comparing ${\chi }_1^B/{\chi }_2^B$ along the $T_{pc}({\mu }_B)$ with the experimentally measured net-proton cumulants ${\chi }_1^p/{\chi }_2^p$. We find that $\{{\mu }_B^f,T_{pc}({\mu }_B^f)\}$ are consistent with the freeze-out parameters of the statistical-model fits to experimentally measured hadron yields for $\sqrt{s_{NN}}\ge 11.5\mathrm{GeV}$.

We compute the one-loop contributions to spin-averaged generalized parton distributions (GPDs) in the proton from pseudoscalar mesons with intermediate octet and decuplet baryon states at nonzero skewness. Our framework is based on nonlocal covariant chiral effective theory, with ultraviolet divergences regularized by introducing a relativistic regulator derived consistently from the nonlocal Lagrangian. Using the splitting functions calculated from the nonlocal Lagrangian, we find the nonzero skewness GPDs from meson loops by convoluting with the phenomenological pion GPD and the generalized distribution amplitude, and verify that these satisfy the correct polynomiality properties. We also compute the lowest two moments of GPDs to quantify the meson loop effects on the Dirac, Pauli, and gravitational form factors of the proton.

We investigated the pionic transitions between the $X_2$ [spin-2 partner of the $X(3872)$] and ${\chi }_{c1,2}$ using a nonrelativistic effective field theory. The $X_2$ is assumed to be a bound state of the $D^{*}$ and ${\overline{D}}^{*}$ mesons and to decay through several kinds of loops, including the bubble, triangle, and box loops. Within the present model, the widths for the single-pion decays $X_2\to {\pi }^0{\chi }_{cJ}$ are predicted to be about 3–30 keV. For the dipion decays, the widths are a few keVs. These widths yield a branching fraction of ${10}^{-3}–{10}^{-2}$. The ratio $R_{\mathrm{c}0}=\mathrm{\Gamma }(X_2\to {\pi }^{+}{\pi }^{-}{\chi }_{cJ})/\mathrm{\Gamma }(X_2\to {\pi }^0{\pi }^0{\chi }_{cJ})\simeq 1.6$, which is a bit smaller than the expected value of 2, and $R_{21}=\mathrm{\Gamma }(X_2\to \pi \pi {\chi }_{c2})/\mathrm{\Gamma }(X_2\to \pi \pi {\chi }_{c1})\simeq 0.85$. These ratios are nearly independent of the $X_2$ mass and the coupling constants, which might be a good quantity for the experiments. Moreover, the invariant mass spectra of the ${\pi }^0{\chi }_{cJ}$ final state for the dipion processes are presented, showing a cusp structure at the $D{\overline{D}}^{*}$ threshold enhanced and narrowed by the nearby triangle singularity.

In this work a rotating SU(2) gluon system has been studied with the framework of a dyon ensemble. By solving the rotation-modified Yang-Mills equation we have obtained rotational corrections to the so-called dyon solutions with arbitrary centers to $\mathcal{O}({\omega }^2)$ order and the corresponding semiclassical potential. In the dyon dilute limit, the radial position-dependent deconfinement temperature has been obtained by minimizing the semiclassical potential in both real and imaginary angular velocity cases. Although without the rotation-dependent coupling constant the critical temperature, as a function of $\omega$, behaves differently from the lattice simulation at each radial position, its radial dependence is qualitatively the same as the recent lattice result. That is, in the real velocity case the outer layer will deconfine in a more difficult manner while the reverse is true in the imaginary velocity case.

Inspired by the BESIII newest observation of X(2370) glueball-like particle, we search its productions in both $e^{+}{e}^{-}$ collisions at $\sqrt{s}=4.95\mathrm{GeV}$ and proton-proton (pp) collisions at $\sqrt{s}=13\mathrm{TeV}$ with a parton and hadron cascade model PACIAE. In this model, the final partonic state (FPS) and the final hadronic state (FHS) are consecutively simulated and recorded. The X(2370) glueball- or tetraquark-state is then, respectively, recombined by two gluons or four quarks $ss\overline{s}\overline{s}$ in the FPS using the quantum statistical mechanics inspired dynamically constrained phase-space coalescence (DCPC) model. The X(2370) molecular-state is recombined by the baryon-antibaryon of $\mathrm{\Lambda }\text{−}\overline{\mathrm{\Lambda }}$ or $\mathrm{\Sigma }\text{−}\overline{\mathrm{\Sigma }}$, or by three mesons of ${\pi }^{+}{\pi }^{-}{\eta }^{\prime }$, $K^{+}{K}^{-}{\eta }^{\prime }$, or $K_S^0{K}_S^0{\eta }^{\prime }$ in the FHS using DCPC model. In both $e^{+}{e}^{-}$ and pp collisions, significant discrepancies in the yields, the transverse momentum spectra and the rapidity distributions among the X(2370) glueball-, tetraquark-, and molecular-state are observed. These discrepancies are proposed as valuable criteria identifying the X(2370) different states from each other. Our results not only support the BESIII observation of glueball-like particle X(2370) production in $e^{+}{e}^{-}$ collisions, but also serve as a prediction for the X(2370) production in pp collisions. We strongly suggest the experimental measurement of the X(2370) glueball-like particle production in pp collisions at the LHC energies.

This paper presents a search for exotic decays of the Higgs boson into a pair of new pseudoscalar particles, $H\to aa$, where one pseudoscalar decays into a $b$-quark pair and the other decays into a $\tau$-lepton pair, in the mass range $12\le m_a\le 60\mathrm{GeV}$. The analysis uses $pp$ collision data at $\sqrt{s}=13\mathrm{TeV}$ collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of $140{\mathrm{fb}}^{-1}$. No significant excess above the Standard Model (SM) prediction is observed. Assuming the SM Higgs boson production cross section, the search sets upper limits at 95% confidence level on the branching ratio of Higgs bosons decaying into $b\overline{b}{\tau }^{+}{\tau }^{-}$, $\mathcal{B}(H\to aa\to b\overline{b}{\tau }^{+}{\tau }^{-}$), between 2.2% and 3.9% depending on the pseudoscalar mass.

Analyzing $e^{+}{e}^{-}$ collision data corresponding to an integrated luminosity of $7.33{\mathrm{fb}}^{-1}$ collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we measure the branching fraction of the semileptonic decay $D_s^{+}\to K^0{e}^{+}{\nu }_e$ to be $(2.98\pm 0.23_{\mathrm{stat}}\pm 0.12_{\mathrm{syst}})\times {10}^{-3}$. Based on fit to the partial decay rates in various $q^2$ intervals, the product value of $D_s^{+}\to K^0$ hadronic form factor and Cabibbo-Kobayashi-Maskawa element is measured to be $f_{+}^{K^0}(0)|V_{cd}|=0.143\pm 0.011_{\mathrm{stat}}\pm 0.003_{\mathrm{syst}}$. With $|V_{cd}|=0.22486\pm 0.00067$ as an input, the hadronic form factor is evaluated to be $f_{+}^{K^0}(0)=0.636\pm 0.049_{\mathrm{stat}}\pm 0.013_{\mathrm{syst}}$. The branching fraction and form factor measurements are factors of 1.6 and 1.7 more precise than the previous world averages, respectively.

Inspired by the recent observation of the Higgs boson radiative decay into $Z^0$ by ATLAS and CMS Collaborations, we investigate the next-to-leading-order (NLO) electroweak correction to this rare decay process in Standard Model (SM). Implementing the on shell renormalization scheme, we find that the magnitude of the NLO electroweak correction may reach 7% of the leading-order (LO) prediction, much more significant than that of the NLO QCD correction, which is merely about 0.3%. After incorporating the $\mathcal{O}(\alpha )$ correction, the predicted partial width from various $\alpha$ schemes tend to converge to each other. Including both NLO electroweak and QCD corrections, the SM prediction for the branching fraction shifts from the LO value of $(1.40–1.71)\times {10}^{-3}$ to $(1.55\pm 0.06)\times {10}^{-3}$, considerably lower than the measured value ${\mathcal{B}}_{\exp }[H\to Z^0\gamma ]=(3.4\pm 1.1)\times {10}^{-3}$. Resolving this discrepancy clearly calls for further theoretical investigations, and, more importantly, experimental efforts from HL-LHC and the prospective Higgs factories such as CEPC and FCC-ee.

We explore alternative formulations of the analogy between viable Horndeski gravity and Eckart’s first-order thermodynamics. We single out a class of identifications for the effective stress-energy tensor of the scalar field fluid that, upon performing the imperfect fluid decomposition, yields constitutive relations that can be mapped onto Eckart’s theory. We then investigate how different couplings to Einstein’s gravity, at the level of the field equations, can affect the thermodynamic formalism overall. Last, we specialize the discussion to the case of “traditional” scalar-tensor theories and identify a specific choice of the coupling function that leads to a significant simplification of the formalism.

Following the work of Capstick and Isgur [Phys. Rev. D 34, 2809 (1986)], we systematically study the mass spectrum of the heavy baryons in the relativized quark potential model with chromodynamics. Besides the original Godfrey-Isgur (GI) model, we also adopt a modified GI model which replaces the linear confinement by a screened one. The two models give similar results in our work. All heavy baryons observed so far can be explained as three-quark states. In particular, we identify the ${\mathrm{\Omega }}_c(3000)/{\mathrm{\Omega }}_b(6316)$, ${\mathrm{\Omega }}_c(3050)/{\mathrm{\Omega }}_b(6330)$, ${\mathrm{\Omega }}_c(3065)/{\mathrm{\Omega }}_b(6340)$, and ${\mathrm{\Omega }}_c(3090)/{\mathrm{\Omega }}_b(6350)$ states as the $p_{\lambda }$ excitations with quantum numbers $1/2^{-}$, $3/2^{-}$, $3/2^{-}$, and $5/2^{-}$. The ${\mathrm{\Omega }}_c(3120)$ is a $3/2^{-}$ state with the $p_{\rho }$ excitation, whose bottom partner is predicted to be ${\mathrm{\Omega }}_b(6446/6457,3/2^{-})$. The higher state ${\mathrm{\Omega }}_c(3188)$ is the $2s_{\lambda }$ excitation with quantum numbers $1/2^{+}$, and ${\mathrm{\Omega }}_c(3327)$ is a $d_{\lambda }$ excitation with quantum numbers $3/2^{+}$ or $5/2^{+}$.

We analyze data from the CsI, liquid Ar and Ge detectors of the COHERENT experiment and confirm within $1.5\sigma$ that the measured elastic neutrino-nucleus scattering cross section is proportional to the square of the number of neutrons in the nucleus, as expected for coherent scattering in the standard model. We also show how various degeneracies involving nonstandard neutrino interaction parameters are broken in a combined analysis of the three datasets.

The decay $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ is an ideal process in which to study flavor-conserving $C$ and $CP$ violation beyond the Standard Model. We deduce the $C$- and $CP$-odd quark operators that contribute to $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ originating from the mass-dimension-six Standard Model effective field theory. The corresponding hadron-level operators that generate a nonvanishing $I=0$ amplitude at order $p^6$ in the chiral effective theory are presented for the first time, to the best of our knowledge, in addition to the leading-order operators ascribed to the $I=2$ final state. By fitting the KLOE-2 and the most recent BESIII experimental data, we determine the coefficients of the lowest-order $I=0$ and $I=2$ amplitudes and estimate the potential new physics energy scale. We also perform an impact study of the future $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ experiments.

Thermal photons produced in heavy-ion collision experiments are an important observable for understanding quark-gluon plasma (QGP). The thermal photon rate from the QGP at a given temperature can be calculated from the spectral function of the vector current correlator. Extraction of the spectral function from the lattice correlator is known to be an ill-conditioned problem, as there is no unique solution for a spectral function for a given lattice correlator with statistical errors. The vector current correlator, on the other hand, receives a large ultraviolet contribution from the vacuum, which makes the extraction of the thermal photon rate difficult from this channel. We therefore consider the difference between the transverse and longitudinal part of the spectral function, only capturing the thermal contribution to the current correlator, simplifying the reconstruction significantly. The lattice correlator is calculated for light quarks in quenched QCD at $T=470\mathrm{MeV}$ ($\sim 1.5T_c$), as well as in $2+1$ flavor QCD at $T=220\mathrm{MeV}$ ($\sim 1.2T_{pc}$) with $m_{\pi }=320\mathrm{MeV}$. In order to quantify the nonperturbative effects, the lattice correlator is compared with the corresponding $\mathrm{NLO}+{\mathrm{LPM}}^{\mathrm{LO}}$ estimate of correlator. The reconstruction of the spectral function is performed in several different frameworks, ranging from physics-informed models of the spectral function to more general models in the Backus-Gilbert method and Gaussian process regression. We find that the resulting photon rates agree within errors.

In this paper we continue to develop the homotopy method for solving of the nonlinear evolution equation for the diffractive production in deep inelastic scattering. We introduce part of the nonlinear corrections as a first step of this approach. This simplified nonlinear evolution equation is solved analytically taking into account the initial and boundary conditions for the process. At the second step of our approach we demonstrated that the perturbative procedure can be used for the remaining parts of the nonlinear corrections. It turns out that these corrections are small and can be estimated in the regular iterative procedure.

We start from a recently favored picture in which the ${\mathrm{\Lambda }}_c(2940)$ and ${\mathrm{\Lambda }}_c(2910)$ correspond mostly to $N{D}^{*}$ bound states with $J^P=1/2^{-},3/2^{-}$ respectively, and then add a $D$ as a third particle, looking for the possible binding of the $DN{D}^{*}$ three-body system within the framework of the fixed center approximation. We find that the system is bound with respect to the corresponding ${\mathrm{\Lambda }}_c(2940)D$, ${\mathrm{\Lambda }}_c(2910)D$ thresholds with a binding of about 60 MeV and a width of about 90 MeV. Alternatively we assume a cluster of $ND$ and a $D^{*}$ meson interacting with the cluster, and we find similar results. The observation of these states of $J^P=1/2^{+},3/2^{+}$ would provide new and valuable information concerning the $DN$ and $D^{*}N$ interaction, an issue of current debate.

Based on $(2712.4\pm 14.1)\times {10}^6\psi (2S)$ events, $7.9{\mathrm{fb}}^{-1}\psi (3773)$ data, and $0.8{\mathrm{fb}}^{-1}$ off-resonance data samples collected with the BESIII detector, we measure the branching fraction of $\psi (2S)\to \gamma {\pi }^0$ and $e^{+}{e}^{-}\to \gamma {\pi }^0$ form factor at momentum transfers $Q^2\sim 13{\mathrm{GeV}}^2$. The $e^{+}{e}^{-}\to \gamma {\pi }^0$ cross section is fitted with considering the interference between the $\psi (2S)$ and continuum amplitudes and two solutions are found, $\mathcal{B}=3.74\times {10}^{-7}$ with $\varphi =3.93\mathrm{rad}$ and $\mathcal{B}=7.87\times {10}^{-7}$ with $\varphi =2.08\mathrm{rad}$. Here, $\mathcal{B}$ is the branching fraction of $\psi (2S)\to \gamma {\pi }^0$ and $\varphi$ is the relative phase angle between the $\psi (2S)$ and continuum amplitudes. Due to insufficient off-resonance data, the branching fraction $\mathcal{B}(\psi (2S)\to \gamma {\pi }^0)$ is determined to be in the range $[2.7,9.7]\times {10}^{-7}$ within 1 standard deviation of the contour region.

We describe a procedure to determine moments of parton distribution functions of any order in lattice quantum chromodynamics (QCD). The procedure is based on the gradient flow for fermion and gauge fields. The flowed matrix elements of twist-2 operators renormalize multiplicatively, and the matching with the physical matrix elements can be obtained using continuum symmetries and the irreducible representations of Euclidean 4-dimensional rotations. We calculate the matching coefficients at one-loop in perturbation theory for moments of any order in the flavor nonsinglet case. We also give specific examples of operators that could be used in lattice QCD computations. It turns out that it is possible to choose operators with identical Lorentz indices and still have a multiplicative matching. One can thus use twist-2 operators exclusively with temporal indices, thus substantially improving the signal-to-noise ratio in the computation of the hadronic matrix elements.

Junction conditions play a crucial role in constructing new gravity solutions. In this paper, we derive the junction condition for gluing together an arbitrary number of spacetimes along a common interface. We develop a geometric technique of reverse extension and provide precise definitions of geometric quantities at the interface. This leads to a geometric derivation of the multiway junction condition. As a cross-check, we independently rederive the junction condition by varying the action of some specific gravitational models including both Einstein gravity and dilaton gravity. We demonstrate that the junction condition is invariant under a change of frames, and the form of the junction condition is the same for both space- and timelike interfaces.