Search

In this paper, we study pair production of ψ[1S] and ψ[2S] charmonium states in the forward rapidity region of the LHCb experiment at the s=13TeV using the improved color evaporation model and the parton Reggeization approach, which is a gauge invariant version of the kT–factorization approach. Taking into account single and double parton scattering mechanisms and using the set of model parameters which have been fixed early, we compare our theoretical predictions with the recent LHCb experimental data as well as with another theoretical predictions. The numerical calculations are performed using the parton–level Monte–Carlo event generator KaTie and modified KMRW model for unintegrated parton distribution functions. We have found absolutely dominant role of the double parton scattering mechanism in the charmonium pair production at the LHCb. [ABSTRACT FROM AUTHOR]

In this paper, we consider a heavy quarkonium state in a hot QCD medium, namely the ground state of charmonium and bottomonium. The quark–antiquark potential is proposed in the form of a temperature-dependent Cornell potential, and is extended to include a temperature-dependent parameter. Then, for the proposed potential with different parametrizations of the Debye mass, the N-dimensional Schrödinger equation is analytically solved using the biconfluent Heun equation. The obtained energy eigenvalues and wave functions are employed to study the flavor dependence, the effect of dimensionality and the influence of the additional term on the mass and binding energy of 1S state of charmonium and bottomonium at finite temperature. The findings of this research are compared to those from past studies. We concluded that this work provides a simple and consistent description of quarkonium states at finite temperature in a hot QCD medium, highlighting the effect of noncompact extra dimensions and the flavor dependence of the binding energies of heavy quarkonia. [ABSTRACT FROM AUTHOR]

In this paper, we study the dissociation of heavy quarkonium in the spinning black hole background. Specifically, we analyze the spectral function of charmonium and bottomonium in the spinning black hole background and examine how the angular momentum affects the dissociation of J / Ψ and Υ (1 S) . From the results, we find that the angular momentum and temperature decreases the peak height and expands the peak width of the spectral function, thereby enhancing the dissociation of heavy vector mesons. Moreover, the angular momentum has a stronger dissociation effect in the transverse orientation, revealing the directional influence of angular momentum. [ABSTRACT FROM AUTHOR]

Charmonium production cross-section in proton–proton collisions is measured at the centre-of-mass energy s = 13 TeV using decays to p p ¯ final state. The study is performed using a data sample corresponding to an integrated luminosity of 2.2 fb - 1 collected in 2018 with the LHCb detector. The production cross-section of the η c meson is measured in a rapidity range of 2.0 < y < 4.0 and in a transverse momentum range of 5.0 < p T < 20.0 GeV / c , which is extended compared with previous LHCb analyses. The differential cross-section is measured in bins of p T and, for the first time, of y. Upper limits, at 90% and 95% confidence levels, on the η c (2 S) and h c (1 P) prompt production cross-sections are determined for the first time. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of charmonium S-states by solving the Schrödinger equation with Cornell plus spin–spin interaction term via the artificial neural network (ANN) approach. From the solutions provided by ANN approach, we propose possible assignments for some of the recently discovered charmonium-like resonances. For simplicity purpose, we restricted the study to the ground and radially excited S-states of charmonium. The charmonium wave function is represented by the feed forward ANN and its inputs are assimilated to coordinate values. We calculated the masses, hyperfine splittings, spin-averaged mass spectrum and Regge trajectories of pseudoscalar and vector charmonium states. Overall, our results are in good accordance with the available experimental data and past studies of the mass spectrum of J PC = 1 − − and J PC = 0 − + charmonium states. Further, we propose a possible assignment for some of the recently discovered charmonium-like mesons. We concluded that η c (3 S) , η c (4 S) , ψ (4 S) , η c (5 S) and ψ (6 S) are, respectively, good candidates of X (3 9 4 0) , X (4 1 6 0) , Y (4 2 6 0) , ψ (4 4 1 5) and Y (4 6 6 0) charmonium-like resonances. [ABSTRACT FROM AUTHOR]

We have investigated the internal structure of the open- and hidden-charmed ( DD ∗ / D ¯ D ∗ ) molecules in the unified framework. We first fit the experimental lineshape of the T cc + state and extract the DD ∗ interaction, from which the T cc + is assumed to arise solely. Then we obtain the D D ¯ ∗ interaction by charge conjugation. Our results show that the D D ¯ ∗ interaction is attractive but insufficient to form X (3872) as a bound state. Instead, its formation requires the crucial involvement of the coupled channel effect between the D D ¯ ∗ and c c ¯ components, although the c c ¯ accounts for approximately 1 % only. Besides X (3872) , we have obtained a higher-energy state around 3957.9 MeV with a width of 16.7 MeV, which may be a potential candidate for the X (3940). In J PC = 1 + - sector, we have found two states related to the iso-scalar X ̃ (3872) and h c (2 P) , respectively. Our combined study provides valuable insights into the nature of these DD ∗ / D D ¯ ∗ exotic states. [ABSTRACT FROM AUTHOR]

The investigation of charm physics plays an important role in checking the Standard Model’s description of strong and weak interactions, validating its predictions for particle physics, and exploring new physics beyond the Standard Model. Using a large dataset from e+e− annihilation, BESIII has conducted comprehensive and extensive studies in the areas of hadronic, leptonic and semileptonic decays. This proceeding presents an overview of the recent researches and discoveries by BESIII on decays of charmed baryons, charmed mesons and charmonium states, highlighting their significance in advancing the understanding of new physics, experimental determination of physical parameters and improvement of measurement precision. [ABSTRACT FROM AUTHOR]

In this work, we investigate the decays of meson X(4160) in the molecular frame. By using an effective lagrangian approach, we calculate the widths of X (4160) → J / ψ ϕ , D ∗ D ¯ ∗ , D ∗ D ¯ and D D ¯ through the triangle loop mechanism in the molecular scenario. Based on the compositeness condition, the coupling between X(4160) and the D s ∗ D ¯ s ∗ molecular state is determined. The other coupling constants used are determined phenomenologically. The calculation of the decay widths shows that the D ∗ D ¯ ∗ decay mode has a larger branching ratio. These predictions can be seen as a test for the charmonium assignment of X(4160). [ABSTRACT FROM AUTHOR]

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 0 1 , V 2 1 , V 1 1 and V 3 1 ), the screening parameter δ 0 , and non-commutativity parameters (Φ / η ¯ , χ / χ ¯ and ζ / ζ ¯). 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. [ABSTRACT FROM AUTHOR]

We provide an update on our semi-classical transport approach for quarkonium production in high-energy heavy-ion collisions, focusing on J / ψ and ψ (2 S) mesons in 5.02 TeV Pb-Pb collisions at the Large Hadron Collider (LHC) at both forward and mid-rapidity. In particular, we employ the most recent charm-production cross sections reported in pp collisions, which are pivotal for the magnitude of the regeneration contribution, and their modifications due to cold-nuclear-matter (CNM) effects. Multi-differential observables are calculated in terms of nuclear modification factors as a function of centrality, transverse momentum, and rapidity, including the contributions from feeddown from bottom hadron decays. For our predictions for ψ (2 S) production, the mechanism of sequential regeneration relative to the more strongly bound J / ψ meson plays an important role in interpreting recent ALICE data. [ABSTRACT FROM AUTHOR]

The recent results on charmonium production at BESIII are reviewed, including the observation of charmonium-like states in the processes of electron–positron annihilation into , , , and final states, as well as the study of the prompt inclusive production of the and mesons. [ABSTRACT FROM AUTHOR]

In this study, we solved the Schrödinger wave equation by using effective potential in an artificial neural network (ANN) for the mass spectrum of different charmonium states, including η c , ψ 2 , χ 2 , and χ 4 . The ANN approach provides an efficient, more general, and continuous solution-approximating strategy, thus eliminating the possibility of skipping any region of interest in mass spectroscopy. The close consistency of ANN results with the already-reported results from numerical and theoretical approaches and experimental ones shows the reliability and accuracy of the ANN approach. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this work, the approximate bound state solutions of the fractional Schr¨odinger equation under a spin-spin-dependent Cornell potential are obtained via the convectional Nikiforov-Uvarov approach. The energy spectra are applied to obtain the mass spectra of the heavy mesons such as bottomonium, charmonium and bottom-charm. The masses for the singlet and triplet spin numbers increase as the quantum numbers increase. The fractional Schr¨odinger equation improves the mass spectra compared to other theoretic masses. The bottomonium masses agree with the experimental results where percentage errors for fractional parameters of β = 1, α = 0.97 and β = 1, α = 0.50 were found to be 0.67% and 0.49% respectively. The respective percentage errors of 1.97% and 1.62% for fractional parameters of β = 1, α = 0.97 and β = 1, α = 0.50 were obtained for charmonium meson. The results indicate that the potential curves coupled with the fractional parameters account for the short-range gluon exchange between the quark-antiquark interactions and the linear confinement phenomena which is associated with the quantum chromo-dynamic and phenomenological potential models in particle and high-energy physics. [ABSTRACT FROM AUTHOR]

We study the role of 1 → 2 and 1 → 3 processes in triple charmonium production in the leading logarithmic approximation (LLA). We see that the ratio of effective cross sections of TPS and DPS only moderately depends on charmonium transverse momenta, but the total DPS and TPS cross sections each separately may have rather strong dependence on charmonia transverse momenta in the central kinematics region that can be studied experimentally. [ABSTRACT FROM AUTHOR]

In this study, we investigate the potential of heavy quarkonia within a magnetized hot QGP medium having finite momentum anisotropy. The phenomenon of inverse magnetic catalysis is introduced into the system, influencing the magnetic field-modified Debye mass and thereby altering the effective quark masses. Concurrently, the impact of momentum anisotropy in the medium is considered that influence the particle distribution in the medium. The thermal decay width and dissociation temperature of quarkonium states, specifically the 1S and 2S states of charmonium and bottomonium, are computed. Our results reveal that both momentum anisotropy and the inverse magnetic catalysis effects play a significant role in modifying the thermal decay width and dissociation temperature of these heavy quarkonia states. [ABSTRACT FROM AUTHOR]

The exotic states X(3872) and Z c (3900) have long been conjectured as isoscalar and isovector D ¯ ∗ D molecules. In this work, we first propose the triangle diagram mechanism to investigate their productions in B decays as well as their heavy quark spin symmetry partners, X 2 (4013) and Z c (4020) . We show that the large isospin breaking of the ratio B [ B + → X (3872) K + ] / B [ B 0 → X (3872) K 0 ] can be attributed to the isospin breaking of the neutral and charged D ¯ ∗ D components in their wave functions. For the same reason, the branching fractions of Z c (3900) in B decays are smaller than the corresponding ones of X(3872) by at least one order of magnitude, which naturally explains its non-observation. A hierarchy for the production fractions of X(3872), Z c (3900) , X 2 (4013) , and Z c (4020) in B decays, consistent with all existing data, is predicted. Furthermore, with the factorization ansatz we extract the decay constants of X(3872), Z c (3900) , and Z c (4020) as D ¯ ∗ D (∗) molecules via the B decays, and then calculate their branching fractions in the relevant B (s) decays, which turn out to agree with all existing experimental data. The mechanism we proposed is useful to elucidate the internal structure of the many exotic hadrons discovered so far and to extract the decay constants of hadronic molecules, which can be used to predict their production in related processes. [ABSTRACT FROM AUTHOR]

Strong decays of the charmonium-like state Y(4320) have been studied in the framework of the covariant confined quark model. The resonance Y has been interpreted as a four-quark state with molecular-type interpolating current. We evaluate the hidden-charm decay width of Y into a vector and a scalar, with the latter decaying subsequently to a pair of charged pseudoscalar states. The strong decay mode Y → π + π - J / Ψ has been studied by involving the scalar resonances f 0 (500) and f 0 (980) , considered quark-antiquark states, while the mode Y → K + K - J / Ψ -via f 0 (980) . We have calculated the partial widths of the related strong decays and the branching ratio B (Y → K + K - J / Ψ) / B (Y → π + π - J / Ψ) , recently determined by the BESIII collaboration. The estimated branching ratio and calculated partial strong decay widths are in reasonable agreement with the latest experimental data. [ABSTRACT FROM AUTHOR]

The mass spectra of light-heavy tetraquarks c q c ̄ q ̄ (q = u , d) are computed in a nonrelativistic diquark model with one-gluon exchange plus confining potential. In the diquark model, a c q c ̄ q ̄ state is regarded to be made of a light-heavy diquark (q c) and an antidiquark q ̄ c ̄ in antitriplet and triplet color configuration, respectively. The masses of charm mesons were calculated in order to fit the model parameters used to create the masses of tetraquarks and therefore enhance the model's reliability. The masses of (c q c ̄ q ̄) tetra-quark states are determined to be in the range of 3.8–4.7 GeV, which is consistent with the experimentally reported charmonium-like states. In particular, the Z c (3 9 0 0) , Z c (4 4 3 0) and ψ (4 6 6 0) tetraquarks, which have been seen experimentally, may all be described by our model. [ABSTRACT FROM AUTHOR]

We establish a statistical two-body fractal (STF) model to study the spectrum of J / ψ . J / ψ serves as a reliable probe in heavy-ion collisions. The distribution of J / ψ in hadron gas is influenced by flow, quantum and strong interaction effects. Previous models have predominantly focused on one or two of these effects while neglecting the others, resulting in the inclusion of unconsidered effects in the fitted parameters. Here, we study the issue from a new point of view by analyzing the fact that all three effects induce a self-similarity structure, involving a J / ψ - π two-meson state and a J / ψ , π two-quark state, respectively. We introduce modification factor q T B S and q 2 into the probability and entropy of charmonium. q T B S denotes the modification of self-similarity on J / ψ , q 2 denotes that of self-similarity and strong interaction between c and c ¯ on quarks. By solving the probability and entropy equations, we derive the values of q T B S and q 2 at various collision energies and centralities. Substituting the value of q T B S into distribution function, we successfully obtain the transverse momentum spectrum of low- p T   J / ψ , which demonstrates good agreement with experimental data. The STF model can be employed to investigate other mesons and resonance states. [ABSTRACT FROM AUTHOR]

The deformed Klein–Gordon equation has been solved in three-dimensional extended relativistic quantum mechanics (3D-ERQM) symmetries for the newly improved screened Kratzer potential (NISKP) model under the influence of the deformation space–space symmetries. The new relativistic energy eigenvalues were calculated using the parametric Bopp's shift method and standard perturbation theory in addition to the approximation scheme suggested by Greene and Aldrich for the inverse square terms. The new relativistic energy eigenvalues of (LiH, HCl, CO and H2) molecules under the NISKP model were shown to be sensitive to the atomic quantum numbers (j , l , s , m), mixed potential depths ( D e , r e ), the screening parameter's inverse (α , δ) , control parameter τ and non-commutativity parameters (Θ , β , ζ). In addition, we analyzed the non-relativistic energy values by applying the well-known transmission rules known in the literature. Furthermore, we studied many special cases useful to researchers in the framework of the new extended symmetries, such as the new screened cosine Kratzer potential, the new screened Kratzer potential (SKP), the new Kratzer potential, the new coshine Yukawa potential, the new coshine Yukawa potential, the new shifted improved SKP and the new shifted SKP. The study is further extended to calculate the mass spectra of mesons of the heavy quarkonium system such as charmonium c c ¯ , bottomonium b b ¯ , b ¯ c and light mesons c s ¯ and b s ¯ that have the quark and antiquark flavor within the framework of the NISKP model in 3D-ENRQM symmetries. [ABSTRACT FROM AUTHOR]

We study the production of ground and excited axial charmonia in processes, e - e + → h c (n P) + η c (n ′ S) , and e - e + → χ c 1 (n P) + h c (n ′ P) for n , n ′ = 1 , 2 , through leading order tree-level diagrams ∼ O (α em α s) , which proceed through exchange of a virtual photon and an internal gluon line connecting two quark lines in the triangle quark loop part of the diagram at center of mass energy, s = 10.6 GeV . We employ the framework of 4 × 4 Bethe–Salpeter equation, and calculate their cross sections. These studies might be of interest for future experiments at B-factories, since h c , η c , and χ c 1 , h c production might provide opportunities for observing h c with higher statistics in future. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the masses of the pseudoscalar (D ( D 0 , D + ), D ̄ ( D 0 ̄ , D − ) and vector open charm mesons ( D ∗ ( D ∗ 0 , D ∗ + ), D ̄ ∗ ( D ̄ ∗ 0 , D ∗ − ) as well as the pseudoscalar ( η c (1 S) , η c (2 S)) and the vector charmonium states (J ∕ ψ , ψ (2 S) , ψ (1 D)) in the asymmetric hot strange hadronic medium in the presence of strong magnetic fields. In the magnetized medium, the mass modification of open charm mesons due to their interactions with baryons and the scalar fields (σ , ζ , and δ) is investigated in a chiral effective model. Moreover, the charged pseudoscalar meson ( D ± ), as well as the longitudinal component of charged vector meson ( D ∗ ± ∥ ), experience additional positive mass modifications in the magnetic field due to Landau quantization. The effect of the modification of gluon condensates simulated by the medium change of dilaton field χ on the masses of the charmonia is also calculated in the chiral effective model. The contribution of masses of light quarks is also considered in the modification of gluon condensates. At high temperatures, the magnetically induced modifications of scalar fields significantly reduce the in-medium masses of mesons. The effects of magnetically induced spin mixing between the pseudoscalar and the corresponding vector mesons are incorporated in our study through a phenomenological effective Lagrangian interaction. The spin mixing result in a positive mass shift for the longitudinal component of the vector mesons and a negative mass shift for the pseudoscalar mesons in the presence of the magnetic field. From the obtained in-medium masses of charmonia and open charm mesons, we have also calculated the partial decay widths of ψ (1 D) to D D ̄ , using a light quark pair creation model, namely, the 3 P 0 model. [ABSTRACT FROM AUTHOR]

The detection of radially excited charmonium and charm meson states, and measurement of heavy meson decays, particularly B c + → J / ψ D s + and B c + → J / ψ D s ∗ + , by the LHCb and ATLAS Collaborations, have aroused a lot of theoretical interest in the nonleptonic decays of b-flavored mesons. In this paper, we study the exclusive two-body nonleptonic B ¯ 0 , B s 0 ¯ , B - and B c - -meson decays to two vector meson ( V 1 (n S) V 2 ) states. Assuming the factorization hypothesis, we calculate the weak-decay form factors from the overlapping integrals of meson wave functions, in the framework of the relativistic independent quark (RIQ) model. We find a few dominant decay modes: B - → D ∗ 0 ρ - , B 0 ¯ → D ∗ + ρ - , B s 0 ¯ → D s ∗ + ρ - , B - → J / ψ K ∗ - and B c - → J / ψ D s ∗ - with predicted branching fractions of 1.52, 1.40, 1.16, 0.46 and 0.27 (in % ), which are experimentally accessible. The predicted branching fractions for corresponding decay modes to excited (2S) states, obtained in O (10 - 3 - 10 - 4) lie within the detection accuracy of the current experiments at LHCb and Tevatron. Our predicted CP-odd fractions ( R ⊥ ) for color-favored B c -decays to two charmful states ( D ∗ D (s) ∗ ) are found significant as compared to similar decay modes of other b-flavored mesons. [ABSTRACT FROM AUTHOR]

Abstract The pion, as the Goldstone boson of the strong interaction, is the lightest QCD bound state and responsible for the long-range nucleon-nucleon interaction inside the nucleus. Our knowledge on the pion partonic structure is limited by the existing Drell-Yan data which are primarily sensitive to the pion valence-quark distributions. The recent progress of global analysis of pion’s parton distribution functions (PDFs) utilizing various experimental approaches are introduced. From comparisons between the pion-induced $$J/\psi$$ J / ψ and $$\psi (2S)$$ ψ ( 2 S ) production data with theoretical calculations using the CEM and NRQCD models, we show how these charmonium production data could provide useful constraints on the pion PDFs.

The article discusses the importance of future tau charm facilities in particle physics research, focusing on the proposed Super Tau-Charm Facility (STCF) by China and Super Charm-Tau Facility (SCTF) by Russia. These facilities aim to explore the transition region between perturbative and non-perturbative quantum chromodynamics (QCD) and test electroweak (EW) theory rigorously. The primary challenge lies in achieving high target luminosity and developing cutting-edge technologies for the accelerator and spectrometer. The International Workshop on Future Tau Charm Facilities (FTCF) brings together researchers to refine scientific questions, discuss key technologies, and promote the development of STCF and SCTF projects. [Extracted from the article]

Using e+e− collision data corresponding to a total integrated luminosity of 12.9 fb−1 collected with the BESIII detector at the BEPCII collider, the exclusive Born cross sections and the effective form factors of the reaction e + e − → Ξ − Ξ ¯ + are measured via the single baryon-tag method at 23 center-of-mass energies between 3.510 and 4.843 GeV. Evidence for the decay ψ 3770 → Ξ − Ξ ¯ + is observed with a significance of 4.5σ by analyzing the measured cross sections together with earlier BESIII results. For the other charmonium(-like) states ψ(4040), ψ(4160), Y(4230), Y(4360), ψ(4415), and Y(4660), no significant signal of their decay to Ξ − Ξ ¯ + is found. For these states, upper limits of the products of the branching fraction and the electronic partial width at the 90% confidence level are provided. [ABSTRACT FROM AUTHOR]

We study the production cross-sections and radiative decay widths of heavy quarkonia (charmonia and bottomonia) in magnetized nuclear matter. The production cross-sections of the ψ (3 7 7 0) and ϒ (4 S) , from the D D ̄ and B B ̄ scatterings, respectively, are studied from the medium modifications of the masses and partial decay widths to open charm (bottom) mesons, of these heavy flavor mesons. Within a chiral effective model, the masses of the vector and pseudoscalar charmonium (bottomonium) states are calculated from the medium modification of a dilaton field, χ , which mimics the gluon condensates of quantum chromodynamics (QCD). The effects of the Dirac sea (DS) and the anomalous magnetic moments (AMMs) of the nucleons are taken into consideration in this study. In the presence of a magnetic field, there is mixing of the pseudoscalar (P) meson and the longitudinal component of the vector (V) meson (PV mixing), which leads to appreciable modifications of their masses. The radiative decay widths of the vector (V) heavy quarkonia to the pseudoscalar (P) mesons (J / ψ → η c (1 S) γ , ψ (2 S) → η c (2 S) γ and ψ (1 D) → η c (2 S) γ for the charm sector and ϒ (N S) → η b (N S) γ , N = 1 , 2 , 3 , 4 , for the bottom sector) in the magnetized asymmetric nuclear matter are also investigated in this work. The difference in the mass of the transverse component from the longitudinal component of the vector meson, arising due to PV mixing, is observed as a double peak structure in the invariant mass spectrum of the production cross-section of ψ (3 7 7 0). This is observed to be appreciably more pronounced as the value of the magnetic field is increased. For the bottomonium (ϒ (4 S)) production cross-section, the effect of the PV mixing effect is observed to be marginal, and there is observed to be a downward shift in the peak position due to the DS contributions. The modifications of the production cross-sections as well as the radiative decay widths of the heavy quarkonia in the magnetized matter should have observable consequences on the production of these heavy flavor mesons resulting from ultra-relativistic peripheral heavy ion collision experiments, where the created magnetic field can be extremely large. [ABSTRACT FROM AUTHOR]

We have studied the dissociation of particle-antiparticle confined systems through a complex potential, which comes from adjusting and correcting both the perturbative and nonperturbative terms at finite temperatures. The real component of the confining nonperturbative potential makes the bound state stronger; in contrast, the absolute value of the imaginary component contributes more significantly to the thermal width at higher temperatures. The results are presented using the relativistic Bethe-Salpeter equation for the real and imaginary parts of the given potential within the framework of the asymptotic pattern and characteristics of the real and imaginarytime Green's functions of the bound state as charged particles that couple to a gauge field in any external field. The relativistic behavior of interaction within the Sturmian representation for two intertwined spaces was extracted based on the mathematical quantum field theory technique in the perturbative calculation of the quantum field theory. The expectation value of the vacuum of field operators is defined as a sum of operator product expansion methods. The results are applied to predict the masses of the charmonium confined state and study the heat dynamics and attributes of the system. The expectation values agree with the experimental and theoretical data found within scholarly works and among academic researchers. [ABSTRACT FROM AUTHOR]

Hard exclusive reactions initiated by pion or photon beams within the near-backward kinematical regime specified by the small Mandelstam variable - u can be studied to access pion-to-nucleon and photon-to-nucleon transition distribution amplitudes (TDAs). Checking the validity of collinear factorized description of pion and photon induced reactions in terms of TDAs allows to test the universality of TDAs between the space-like and time-like regimes that is the indispensable feature of the QCD collinear factorization approach. In this short review, we consider the exclusive pion- and photo-production off nucleon of a highly virtual lepton pair (or heavy quarkonium) in the near-backward region. We first employ a simplistic cross channel nucleon exchange model of pion-to-nucleon TDAs to estimate the magnitude of the corresponding cross sections for the kinematical conditions of J-PARC. We then illustrate the flexibility of our approach by building a two parameter model for the photon-to-nucleon TDAs based on recent results for near threshold J / ψ photoproduction at JLab and provide our estimates for near-backward J / ψ photoproduction and timelike Compton scattering cross sections for the kinematical conditions of JLab and of future EIC and EIcC. [ABSTRACT FROM AUTHOR]

The QCD effective charge extracted from the experimental data is used to construct the vector interaction of a Dirac relativistic model for the charmonium spectrum. The process required to fit the spectrum is discussed and the relationship with a previous study of the vector interaction is analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] We perform a lattice QCD calculation of the η c → 2 γ decay width using a model-independent method that requires no momentum extrapolation of the off-shell form factors. This method also provides a straightforward and simple way to examine the finite-volume effects. The calculation is accomplished using N f = 2 twisted mass fermion ensembles. The statistically significant excited-state effects are observed and eliminated using a multi-state fit. The impact of fine-tuning the charm quark mass is also examined and confirmed to be well-controlled. Finally, using three lattice spacings for the continuum extrapolation, we obtain the decay width Γ η c γ γ = 6.67 (16) stat (6) syst keV, which differs significantly from the Particle Data Group's reported value of Γ η c γ γ = 5.4 (4) keV (2.9 σ tension). We provide insight into the comparison between our findings, previous theoretical predictions, and experimental measurements. [ABSTRACT FROM AUTHOR]

In this paper, we have obtained the analytical and numerical mass spectra of the charmonium and bottomonium mesons using the non-relativistic Schrödinger equation under a spin–spin, spin–orbit and tensor coupled Cornell potential energy. We adopted the Wentzel–Kramers–Brilluoin approximation method to obtain the energy bound equation in closed form. We obtained the potential free parameters by fitting the mass spectra equation to the experimental data of the Particle Data Group. The hyperfine mass splitting of the mesons are obtained for different singlet ( s = 0) and triplet ( s = 1) quantum states ( n 2 s + 1 l j) . Also, the hyperfine multiplet splitting for l > 0 and total angular momentum quantum number j = l , j = l ± 1 were obtained. The results revealed that the charmonium masses ψ (n 3 S 1) and η c (n 1 S 0) ( n = 2 , 3 , 4 , 5 , 6) and bottomonium masses ( η b (n 1 S 0)) and Υ (n 3 S 1) ( n = 2 , 3 , 4 , 6) for the s-wave quantum states are in good agreement with the results obtained by other methods in the existing literature and available experimental data. For l > 0 , the charmonia masses χ c j (n 3 P j) ψ 1 1 3 D 1 and ψ 2 2 3 D 1 agreed with the works obtained using other potential models and observed data. In comparison to experimental data, the total absolute deviation error of 3.21% and 1.06% was obtained for the respective charmonium and bottomonium masses. The proposed potential model provides a satisfying account for the mass spectra of the heavy mesons and may be extended to study other spectroscopic parameters. [ABSTRACT FROM AUTHOR]

This paper discusses the charmonium and bottomonium correlators in the pseudoscalar channel and the corresponding spectral reconstruction on the lattice. The absence of a transport peak in the pseudoscalar channel spectral function allows for an easier study of the in-medium modification of bound states. However, extracting spectral information from Euclidean correlators is still a numerically ill-posed problem. To constrain the spectral reconstruction, we use an ansatz motivated from perturbation theory. The perturbative model spectral function has two main contributions: a thermal part around the threshold obtained from pNRQCD and the vacuum part well above the threshold. These two regions are matched continuously, and the model spectral function is obtained by introducing parameters that control the overall thermal shift of the peak and the overall amplitude. The lattice correlator data is computed using clover-improved Wilson valence fermions on large and fine gauge field configurations generated using N f = 2 + 1 flavors Highly Improved Staggered Quark action with physical strange quark mass m s , and slightly heavy degenerate up and down quark masses m l = m s / 5 that correspond to m π ≃ 320 MeV. Our results obtained at T = 220 MeV and T = 251 MeV suggest that no resonance peaks are needed to describe the charmonium lattice data at these temperatures, while for bottomonium thermally broadened resonance peaks persists. [ABSTRACT FROM AUTHOR]

The BESIII collaboration has discovered a new state with hidden charm-strange. Its mass is intriguingly close to the D s (1968) D ¯ s 1 (2536) threshold and does not have the properties of the charmonium states. Working with the QCD sum rules (QCDSR) approach, we test if the charmonium-like structure Y(4500) , detected in the invariant mass spectrum K + K - J / ψ may be interpreted as an exotic D s (1968) D ¯ s 1 (2536) molecular structure with J PC = 1 - - . Considering the contributions of QCD condensates up to operator dimension ten, we estimate the mass and decay constant of Y(4500) resonance. We get m Y = (4488.35 ± 11.54) MeV in excellent agreement with the meson mass reported by BESIII and f Y = (4.04 ± 0.36) × 10 - 3 GeV 4 . Our findings indicate that a pseudoscalar-axialvector molecule current can well describe this state. [ABSTRACT FROM AUTHOR]

The recently reported strong decays of the charmonium-like state by the BESIII collaboration and the dominant radiative transitions of the charmonium low-lying excited states are studied within a covariant quark model by involving the analytic confinement concept. The resonance is interpreted as a four-quark state of molecular type. We use the compositeness condition to eliminate any constituent degrees of freedom from the space of physical states and rigorously fix the renormalized couplings of the hadron states. The helicity amplitudes, or Lorentz structures, are used to express the gauge-invariant transition amplitudes of the processes under consideration. The fractional strong decay width of is calculated, as is the branching ratio of strong decays (via the resonance) with hidden charms, , as measured by the BESIII Collaboration in 2022. Only one common adjustable parameter for the charmonium states , , , , , and is introduced to describe the quark distribution inside the hadron. We calculate the fractional widths of one-photon radiative decays for the states , , , and . Our estimates of the decay widths of the processes under consideration are in reasonable agreement with the latest experimental data. [ABSTRACT FROM AUTHOR]