Narrow Results

The Belle-II experiment is expected to collect large data samples at the $\mathrm{{\rm Y}}(4S)$ and $\mathrm{{\rm Y}}(5S)$ resonances to study primarily $B$ and $B_s$ mesons. We discuss what other data above the $B\bar{B}$ threshold are of interest. We propose to perform a high-statistics energy scan from the $B\bar{B}$ threshold up to the highest possible energy, and to collect data at the $\mathrm{{\rm Y}}(6S)$ and at higher mass states if they are found in the scan. We emphasize the interest in increasing the maximal energy from 11.24 GeV to 11.5–12 GeV in the future. These data are needed for the investigation of bottomonium and bottomonium-like states.

In the framework of electroweak theory and perturbative quantum chromodynamics, we examine various exclusive decay channels of $W$ bosons that can be fully or partially reconstructed. Our findings provide predictions for the partial widths and address some gaps in previous literature. We also place a strong emphasis on understanding and estimating the associated theoretical uncertainties.

It is pointed out that in the decays the possible "molecular" component of the X(3872) should give rise essentially only to a final state with a predictable spectrum, and should yield virtually no contribution to decays into D⁺D^-γ. The latter final state with charged D mesons should however arise from the radiative decays of the short-distance core of the X(3872) through the transition X(3872) → ψ(3770)γ. Thus an observation of the radiative decays of X(3872) to pairs of neutral and charged D mesons would provide an insight into the internal dynamics of the X(3872) resonance.

We discuss the extension of the superflavor symmetry of doubly heavy baryons to states which contain an excited heavy diquark and we examine some of the consequences of this symmetry for the spectra of doubly heavy baryons and heavy mesons. We explore the ramifications of a proposed symmetry that relates heavy diquarks to doubly heavy mesons. We present a method for determining how the excitation energy of a system containing two heavy quarks will scale as one changes the strength of the interactions and the reduced mass of the system. We use this to derive consequences of the heavy diquark-doubly heavy meson symmetry. We compare these consequences to the results of a quark model as well as the experimental data for doubly and singly heavy mesons. We also discuss the possibility of treating the strange quark as a heavy quark and apply the ideas developed here to strange hadrons.

The mass spectrum of heavy mesons using the Cornell potential is used for studying the quark–antiquark interaction. By appropriately modifying the potential parameters, the established potential models such as Kratzer’s potential and the anharmonic one are applied in the Pekeris approximation. The Schrodinger equation for the Cornell potential setting is solved in this paper via the Nikiforov–Uvarov method. We acquire the confined-state energy spectrum to verify whether the outcome produced by this approach is accurate. The spectrum of energy formulation is used to determine the mass spectra of heavy quarkonium compounds, including charmonium and bottomonium. There is a comparison with various theoretical stances. The outcomes align well with both experimental data and other researchers’ findings.

We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general structures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with $J^{PC}=1^{++}$ binds, which we identify as the reported neutral $X(3872)$. The bottom isotriplet exotic with $J^{PC}=1^{+-}$ binds, and is identified as a mixed state of the reported charged exotics $Z_b^{+}(10610)$ and $Z_b^{+}(10650)$. The bound bottom isosinglet molecule with $J^{PC}=1^{++}$ is a possible neutral $X_b(10532)$ to be observed.

In this paper, we investigate the benefits of machine learning (ML) approaches in predicting the spectra of meson bound states. A linear model (LM) approach is used to predict the spectra of some heavy mesons. Our proposed method has been successfully reproduced in recent experiments, to validate known outcomes. Our results are compared favorably to those obtained using other techniques. This novel perspective opens up a new future in the use of ML in the field of particle physics.

In this paper, we perform a complete non-relativistic study of the improved class of inversely quadratic Yukawa plus Hulthén potential (ICIQYHP) model in the context of three-dimensional non-relativistic non-commutative quantum phase-space (3D-NRNCPS) symmetries impacted by perturbed spin–orbit interaction and the external magnetic fields for the homogeneous (N₂ and O₂) and heterogeneous (CO and NO) diatomic molecules and the heavy meson systems, such as charmonium (cc) and bottomonium (bb) using generalized Bopp’s shifts method and standard perturbation theory with the Greene–Aldrich approximation to the centrifugal barrier. The new non-relativistic energy equation and eigenfunction for the ICIQYHP in the presence of deformation phase–space are obtained to be sensitive to the atomic quantum numbers ($j,l,s,$ and $m$), the mixed potential depths ($V_{01},V_{21},V_{11}$ and $V_{31}$), the screening parameter ${\delta }_0$, and non-commutativity parameters ($\mathrm{\Phi }/\overline{\eta },\chi /\overline{\chi }$ and $\zeta /\overline{\zeta }$). The critical particular cases in 3D-NRNCPS symmetries have been obtained by adjusting the parameters of the ICIQYHP, such as the improved Hulthén potential, the improved Coulomb potential, and the improved inversely quadratic Yukawa potential. We have also studied the spin-averaged mass spectra of the heavy mesons and the thermo-magnetic properties under the class of inversely quadratic Yukawa plus Hulthén potential model in 3D-NRQM and 3D-NRNCPS symmetries. This research can potentially be applied to atomic, condensed matter, nuclear, molecular physics, and chemical physics.

We discuss the possible existence of exotic dibaryons with a heavy antiquark, being realized three-body systems, and B^(*)NN. These are genuinely exotic states with no quark-antiquark annihilation. We consider the heavy quark spin symmetry and chiral symmetry, and introduce the one pion exchange potential between a meson and a nucleon N. As for the NN interaction, we employ the Argonne potential. By solving the coupled-channel equations for PNN and , we find bound and resonant states near the thresholds both in charm and bottom sectors.

The covariant quark model with infrared confinement (CQM) is a well-suited theoretical framework to describe large variety of hadronic processes, including rare decays of heavy mesons. In this text we focus on the reactions $B\to K^{(\ast )}{\mu }^{+}{\mu }^{-}$, which have been recently measured by Refs. 1–4. The measurements include also information about the angular distributions and their significance is given by possible New Physics (NP) effects which are predicted in numerous beyond Standard Model (SM) scenarios. Even with clever choice of experimental observables, a model dependence cannot be fully removed from the theoretical predictions. In this text we present the computation of the $B\to K^{(\ast )}$ form factors within the CQM and give results for some of the most commonly used observables ($A_{FB}$, $F_L$).

We briefly review the formation of pion-mediated heavy-light exotic molecules with both charm and bottom, under the general structures of chiral and heavy quark symmetries. The charm isosinglet exotic molecules with $J^{PC}=1^{++}$ binds, which we identify as the reported neutral $X(3872)$. The bottom isotriplet exotic with $J^{PC}=1^{+-}$ binds, and is identified as a mixed state of the reported charged exotics $Z_b^{+}(10610)$ and $Z_b^{+}(10650)$. The bound bottom isosinglet molecule with $J^{PC}=1^{++}$ is a possible neutral $X_b(10532)$ to be observed.

The possible existence of and BNN states is discussed. They are manifestly exotic dibaryons whose bound states which are stable against a strong decay. As for the interactions, we consider the one pion exchange potential enhanced by the heavy quark spin symmetry. By solving the coupled-channel Schrödinger equations for the three-body systems, we find the bound states with J^P = 0⁻ and resonances with J^P = 1⁻ for I = 0. We also discuss the spin degeneracy of the P_QNN states in the heavy quark mass limit.