Search

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]

We calculated transitions of the higher radial excited charmonia ψ (n S) (n = 3 , 4 , 5) to the orbital excited charmonium h c (1 P) with emission of one pion or eta meson. In calculations, the intermediate S- and P-wave charmed meson loops were considered in terms of the nonrelativistic effective field theory. The results indicate that the transitions of interest are dominated by the loops involving the s l P = (1 / 2) + charmed mesons, whereas the s l P = (1 / 2) - charmed meson loops are of minor contributions. The partial decay widths of ψ (n S) → h c π 0 are of the order of 0.01–1 keV. For the case of ψ (n S) → h c η , the partial decay widths are from 0.1 to 100 keV, implying the branching ratios from 10 - 5 to 10 - 3 . Moreover, the partial decay widths for ψ (n S) → h c η are found to decrease as the η - η ′ mixing angle increases. It is hoped that the present calculated results would be observed in the future experiments. [ABSTRACT FROM AUTHOR]

We make use of published yields for D-mesons and J/ψ in Pb+Pb collisions at ALICE and a schematic description of the expansion of the hadron gas to study D-meson collisions during the hadronic break-up phase as a production mechanism for charmonium in relativistic heavy ion collisions at the Large Hadron Collider. Our calculation is based on chemical reaction rates with thermal cross sections for an effective meson interaction among pseudoscalar and vector mesons. We find that due to regeneration, the newly measured J/ψ yields are consistent with anywhere from roughly 25% to 110% of the total yield present at hadronization time. This allows us to bound the fractional abundance of J/ψ immediately after hadronization: 0.28≤dN0J/ψ/dydNeqJ/ψ/dy≤1.13. Our results are robust under the relaxation of the particulars of our schematic description and imply that it will be difficult to distinguish regeneration during hadronization from regeneration by final-state hadronic interactions. Therefore, regeneration must be taken into account when modeling.

We measure the cross section of e+e− → ηcJ/ψ at the Υ(nS)(n = 1–5) on-resonance and 10.52 GeV off-resonance energy points using the full data sample collected by the Belle detector with an integrated luminosity of 955 fb−1. We also search for double charmonium production in e+e− → ηcJ/ψ via initial state radiation near the ηcJ/ψ threshold. No evident signal of the double charmonium state is found, but evidence for the e+e−→ ηcJ/ψ process is found with a statistical significance greater than 3.3σ near the ηcJ/ψ threshold. The average cross section near the threshold is measured and upper limits of cross sections are set for other regions. [ABSTRACT FROM AUTHOR]

The lowest-lying charmonium-like tetraquarks c c ¯ q q ¯ (q = u , d) and c c ¯ s s ¯ , with spin-parity J P = 0 + , 1 + and 2 + , and isospin I = 0 and 1, are systematically investigated within the theoretical framework of complex-scaling range for a chiral quark model that has already been successfully applied in former studies of various tetra- and penta-quark systems. A four-body S-wave configuration which includes meson–meson, diquark–antidiquark and K-type arrangements of quarks, along with all possible color wave functions, is comprehensively considered. Several narrow resonances are obtained in each tetraquark channel when a fully coupled-channel computation is performed. We tentatively assign theoretical states to experimentally reported charmonium-like signals such as X(3872), Z c (3900) , X(3960), X(4350), X(4685) and X(4700). They can be well identified as hadronic molecules; however, other exotic components which involve, for instance, hidden-color channels or diquark–antidiquark structures play a considerable role. Meanwhile, two resonances are obtained at 4.04 GeV and 4.14 GeV which may be compatible with experimental data in the energy interval 4.0–4.2 GeV. Furthermore, the X(3940) and X(4630) may be identified as color compact tetraquark resonances. Finally, we also find few resonance states in the energy interval from 4.5 to 5.0 GeV, which would be awaiting for discovery in future experiments. [ABSTRACT FROM AUTHOR]

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 / ψ and 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. [ABSTRACT FROM AUTHOR]

J / ψ , a charmonium bound state made of a charm and an anti-charm quark, was discovered in the 1970s and confirmed the quark model. Because the mass of charm quarks is significantly above the quantum chromodynamics (QCD) scale Λ Q C D , charmonia are considered excellent probes to test perturbative quantum chromodynamics (pQCD) calculations. In recent decades, they have been studied extensively at different high-energy colliders. However, their production mechanisms, which involve multiple scales, are still not very well understood. Recently, in high-multiplicity p + p collisions at RHIC and at the LHC, a significant enhancement of J / ψ production yield has been observed, which suggests a strong contribution of multi-parton interaction (MPI). This is different from the traditional pQCD picture, where charm quark pairs are produced from a single hard scattering between partons in p + p collisions. In this work, we will report the J / ψ normalized production yield as a function of normalized charged particle multiplicity over a board range of rapidity and event multiplicity in the J / ψ → μ + μ − channel with PHENIX Run 15 p + p data at s = 200 GeV. The results are compared with PYTHIA 8 simulations with the MPI option turned on and off. Finally, the outlooks of J / ψ in p + A u and A u + p collisions, along with color glass condensate (CGC) predictions and the multiplicity-dependent ψ (2 S) / J / ψ ratio in p + p data, will be briefly discussed. [ABSTRACT FROM AUTHOR]

The measurement of charmonium states produced in proton-neon ( p Ne ) collisions by the LHCb experiment in its fixed-target configuration is presented. The production of J / ψ and ψ (2 S) mesons is studied with a beam of 2.5 Te V protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy s NN = 68.5 Ge V . The data sample corresponds to an integrated luminosity of 21.7 ± 1.4 nb - 1 . The J / ψ and ψ (2 S) hadrons are reconstructed in μ + μ - final states. The J / ψ production cross-section per target nucleon in the centre-of-mass rapidity range y ⋆ ∈ [ - 2.29 , 0 ] is found to be 506 ± 8 ± 46 nb/nucleon . The ratio of J / ψ and D 0 cross-sections is evaluated to (1.06 ± 0.02 ± 0.09) % . The ψ (2 S) to J / ψ relative production rate is found to be (1.67 ± 0.27 ± 0.10) % in good agreement with other measurements involving beam and target nuclei of similar sizes. [ABSTRACT FROM AUTHOR]

The cross-sections of exclusive (coherent) photoproduction J/ψ and ψ(2S) mesons in ultra-peripheral PbPb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV are measured using a data sample corresponding to an integrated luminosity of 228 ± 10 μb−1, collected by the LHCb experiment in 2018. The differential cross-sections are measured separately as a function of transverse momentum and rapidity in the nucleus-nucleus centre-of-mass frame for J/ψ and ψ(2S) mesons. The integrated cross-sections are measured to be σ J / ψ coh = 5.965 ± 0.059 ± 0.232 ± 0.262 mb and σ ψ 2 S coh = 0.923 ± 0.086 ± 0.028 ± 0.040 mb, where the first listed uncertainty is statistical, the second systematic and the third due to the luminosity determination. The cross-section ratio is measured to be σ ψ 2 S coh / σ J / ψ coh = 0.155 ± 0.014 ± 0.003, where the first uncertainty is statistical and the second is systematic. These results are compatible with theoretical predictions. [ABSTRACT FROM AUTHOR]

The collective properties of final state hadrons produced in the high statistics 44 96 Ru + 44 96 Ru and 40 96 Zr + 40 96 Zr collisions at s NN = 200 GeV are found to be significantly different. Such differences were argued to be precise probes of the difference in nucleon distribution in the isobar nuclei. We investigate the J / ψ production in the isobar collision via a relativistic transport approach. By comparing the isobar systems according to equal centrality bin and equal multiplicity bin, we find that the yield ratio of J / ψ is sensitive to the differences in both the number of binary collisions and the medium evolution. Besides, the elliptic flow v 2 of J / ψ is qualitatively different from the light hadrons, and the ratio between Ru + Ru and Zr + Zr collisions is sensitive to the medium evolution. The charmonium production provides an independent probe to study the nucleon distribution in the isobar system. [ABSTRACT FROM AUTHOR]

In this work, we investigate the form factors of B c decays into J / Ψ , ψ (2 S , 3 S) , η c , η c (2 S , 3 S) , χ c 0 , χ c 1 , h c , and X(3872) mesons in the covariant light-front quark model (CLFQM). For the purpose of the branching ratio calculation, the form factors of B c → D (∗) , D s (∗) transitions are also included. In order to obtain the form factors for the physical transition processes, we need to extend these form factors from the space-like region to the time-like region. The q 2 dependence for each transition form factor is also plotted. Then, using the factorization method, we calculate the branching ratios of 80 B c decay channels with a charmonium involved in each mode. Most of our predictions are comparable to the results given by other approaches. As to the decays with the radially excited-state S-wave charmonia involved, such as ψ (2 S , 3 S) and η c (2 S , 3 S) , two sets of parameters for their light-front wave functions, corresponding to scenario I (SI) and scenario II (SII), are adopted to calculate the branching ratios. By comparing with the future experimental data, one can discriminate which parameters are more favored. [ABSTRACT FROM AUTHOR]

[Display omitted] We propose that the X (3915) observed in the J / ψ ω channel is the same state as the χ c 2 (3930) , and the X (3960) , observed in the D s + D s - channel, is an S -wave D s + D s - hadronic molecule. In addition, the J PC = 0 + + component in the B + → D + D - K + assigned to the X (3915) in the current Review of Particle Physics has the same origin as the X (3960) , which has a mass around 3.94 GeV. To check the proposal, the available data in the D D ¯ and D s + D s - channels from both B decays and γ γ fusion reaction are analyzed considering both the D D ¯ - D s D ¯ s - D * D ¯ * - D s * D ¯ s * coupled channels with 0 + + and a 2 + + state introduced additionally. It is found that all the data in different processes can be simultaneously well reproduced, and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73, 3.94, 3.99 and 4.23 GeV, respectively. The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons. [ABSTRACT FROM AUTHOR]

A Schrödinger-type equation for a heavy quarkonium in terms of the dynamical quark mass is obtained in a quasi-particle approach by Llanes-Estrada and Cotanch. To observe the relationship between the obtained equation and the constituent quark (potential) model equation, we treat the dynamical quark mass by a constant parameter M and expand the equation in 1/M up to order (1/M). The equation reduces to that of the traditional nonrelativistic constituent quark model when a nonlocal interaction is neglected. We investigate the nonrelativistic model where the dynamical quark mass M in the Schrödinger-type equation is treated as a free parameter and call it the quasi-quark (QQ) model. To elucidate the role of the nonlocal interaction and to observe the reliability of the QQ model, we studied the charmonium S-wave states. [ABSTRACT FROM AUTHOR]

We study the processes, e − e + → γ ⁎ γ ⁎ → J / ψ + J / ψ , and e − e + → γ ⁎ γ ⁎ → η c + η c at s = 10.6 GeV in the framework of 4 × 4 Bethe-Salpeter equation. For J / ψ + J / ψ production, the dominant contribution is through fragmentation process, while for η c + η c production, the quark rearrangement diagrams contribute. Our results of cross section for J / ψ + J / ψ and ψ (2 S) + ψ (2 S) are compatible with the experimental upper limits set by Belle Collaboration, while in the absence of experimental data for η c (1 S) + η c (1 S) , and η c (2 S) + η c (2 S) production, we have given theoretical prediction of their cross sections, and compared with NRQCD prediction. [ABSTRACT FROM AUTHOR]

Nonleptonic B c decays to P -wave charmonia and light π + , K + , and ρ + , K ∗ + mesons are analyzed using factorization. The hadronic form factors parametrizing the B c → χ c J (h c) matrix elements are expressed in terms of universal functions at the leading order of an expansion in the relative velocity of the heavy quarks in the B c rest-frame and in 1 / m Q . Several ratios of branching fractions are evaluated, and when experimental information can be used, single branching fractions are presented. Both the 1 P and 2 P charmonia are considered. If the exotic candidate state χ c 1 (3 8 7 2) corresponds to χ c 1 (2 P) , it should be produced in nonleptonic B c decays with predicted abundances with respect to the other states in the charmonium 2 P spin four-plet. [ABSTRACT FROM AUTHOR]

Widely applied to both light and heavy meson decay and standing as one of the most successful strong decay models is the 3 P 0 model, in which q q ¯ pair production is the dominant mechanism. In the present, we use the bound-state corrected version of the 3 P 0 , called the C 3 P 0 model, to calculate the decay widths of the charmonium J PC = 1 - - states, nominally J / ψ , ψ (2 S) , ψ (3770) , ψ (4040) , ψ (4160) , ψ (4415) and ψ (4660) to several common channels. [ABSTRACT FROM AUTHOR]

We present a search for the lepton flavor violating decay J/ψ → e±μ∓ using 8.998 × 109J/ψ events collected with the BESIII detector at the BEPCII e+e− storage ring. No excess of signal above background is observed; we therefore set an upper limit on the branching fraction of ℬ (J / ψ → e ± μ ∓) < 4.5 × 10 − 9 at the 90% confidence level. Improving the previous best result by a factor of more than 30, this measurement places the most stringent limit to date on lepton flavor violation in the heavy quarkonium sector. [ABSTRACT FROM AUTHOR]

The analytical solutions of the mass-dependent Klien-Gordon equation (KGE) with the improved harmonic oscillator potential and the improved vector quark-antiquark interaction are derived from the symmetries of three-dimensional relativistic noncommutative quantum mechanics (3D-RNCQM symmetries) using Bopp's shift method and perturbation theory. The energy state equations are sensitive to the global parameters characterizing the noncommutativity space-space (Θ, σ) and the potential parameter (Enl, a, b, c, m0, k) in addition to the discrete atomic quantum numbers (j,l,s,m). The energy spectra for the mass-dependent Shrödinger equation with improved vector quark-antiquark interaction and harmonic oscillator potential were found using nonrelativistic limit principles. We also used the current findings to determine the heavy-meson masses of charmonium cc and bottomonium bb; in both ordinary nonrelativistic quantum mechanics symmetries and three-dimensional nonrelativistic noncommutative 3D-NRNCQM symmetries. [ABSTRACT FROM AUTHOR]

Lorentz scalar and mass interactions are studied in more detail in the framework of a reduced Dirac equation for heavy quark–antiquark mesons. A microscopic model for these interactions is proposed and analyzed. The charmonium mass spectrum is reproduced by means of two free parameters; a third parameter is fixed by means of a phenomenological hypothesis in accordance with the model. [ABSTRACT FROM AUTHOR]

The axial-vector mesons f 1 (1285) and f 1 (1420) are particularly viewed as the mixtures of flavor states f n and f s with mixing angle φ . In order to determine this angle, we study the B d , s 0 → J / ψ f 1 (1285 , 1420) and B d , s 0 → η c f 1 (1285 , 1420) decays in perturbative QCD (PQCD) approach, including the effects of vertex corrections, nonfactorizable diagrams and penguin operators. Not only the branching fractions, but also the direct CP asymmetries and the polarization fractions are calculated. It is found that the branching fractions of these decays are large enough to be measured in the running LHCb and Belle-II experiments. Moreover, in comparison with the observed B (B d , s 0 → J / ψ f 1 (1285)) , B s 0 → (J / ψ , η c) f 1 (1420) decays have large branching fractions, which could be measured promisingly through f 1 (1420) → K S 0 K ± π ∓ in experiments. We also propose several ratios that could be used to further constrain the absolute value of the mixing angle φ , but its sign cannot be determined yet in these decays. The direct CP asymmetries of these decays indicate the penguin pollution in the B d 0 → (J / ψ , η c) f 1 decays cannot be neglected. We acknowledge that there are large theoretical uncertainties arising from the distribution amplitudes of axial-vector mesons and charmonium states, and more precise nonperturbative parameters are called. The comparisons between our results and future experimental data would help us to understand the nature of f 1 states and to test the PQCD approach. [ABSTRACT FROM AUTHOR]

Using proton-proton collision data, collected by the LHCb experiment and corresponding to the integrated luminosity of 9 fb−1, the several new decays to charmonium and three light charged hadrons are observed. In particular, following channels are observed → ψ(2S)π+π−π+, → (ψ(2S) → J/ψπ+π−)π+, → J/ψK+π−π+, and → J/ψK+K−K+. The first evidence of the → ψ(2S)K+K−π+ decays is obtained. The branching fractions of these decays are measured with respect to the high-statistic normalization channels. [ABSTRACT FROM AUTHOR]

Study of the mechanism of heavy quarkonia production is a powerful tool for a better understanding of the dynamics of strong interactions and probably to search for new physics. It is well-known that the fragmentation mechanism is dominant for heavy quarkonia production and forms the nonperturbative aspect of hadron production. Since the main contribution of J ∕ ψ production in high energy processes results from the gluon fragmentation, through this work, we study the fragmentation mechanism of gluon into S-wave vector heavy charmonium J ∕ ψ at lowest order perturbative QCD and extend our work to the noncommutative standard model. To investigate the effects of space–time noncommutativity, we employ the Seiberg–Witten maps. Our results show that the noncommutative effects are considerable, specifically when the gluon transverse momentum is small; p T < 3 0 GeV. [ABSTRACT FROM AUTHOR]

We study D s + D s - and D D ¯ states assuming that they are hadronic molecules with J PC = 0 + + quantum number. We use two-point QCD sum rule formalism and extract the mass and decay constant values of these states. We take into account contributions of various quark, gluon, and mixed vacuum condensates up to dimension eight. The extracted mass and decay constant values of D D ¯ and D s + D s - states read as M D D ¯ = 3795 - 82 + 85 MeV , f D D ¯ = 1. 70 - 0.29 + 0.33 × 10 - 2 GeV 5 , and M D s + D s - = 3983 - 88 + 93 MeV , f D s + D s - = 2. 52 - 0.54 + 0.64 × 10 - 2 GeV 5 , respectively. The predicted mass of D s + D s - state is in good agreement with the recent LHCb observation and supports quantum number and molecular picture assignments. A possible observation of D D ¯ state would help for establishing the lowest four-quark state in charmonium sector. [ABSTRACT FROM AUTHOR]

The feasibility of detection of the charmonium states at the ALICE experiment at the Large Hadron Collider is studied. It is demonstrated that the current resolution of the tracking system and the electromagnetic calorimeter is sufficient for signal discrimination of and . Kinematic selection cuts are optimized for selection of these charmonium states. [ABSTRACT FROM AUTHOR]

We review recent studies about anisotropic flows ( v 1 , v 2 , v 3 ) of charmonium in the quark-gluon plasma produced in relativistic heavy-ion collisions. Collective flows of the bulk medium are developed due to the anisotropic pressure gradient of the medium. Strongly coupled with the bulk medium, charm quarks carry collective flows from the expanding medium, which will be inherited by the regenerated charmonium via the coalescence process. In event-by-event collisions where nucleon positions fluctuate from the smooth distribution, there is triangularity in the medium initial energy density. Triangular flows of the bulk medium and heavy flavor particles can be developed due to the initial fluctuations. In the longitudinal direction, the rapidity-odd distribution of the initial energy density is induced by the rotation of the medium in non-central heavy-ion collisions. Charmonium suffers biased dissociation along positive and negative x-directions in forward (backward) rapidity. The directed flow of charmonium becomes non-zero. The directed, elliptic and triangular flows ( v 1 , v 2 , v 3 ) of charmonium come from the anisotropic initial distributions of the medium energy density in the transverse and longitudinal directions. [ABSTRACT FROM AUTHOR]

In the present work, we have studied the differential scattering cross-section for ground states of charmonium and bottomonium in the frame work of the medium-modified form of quark-antiquark potential and Born approximation using the nonrelativistic quantum chromodynamics approach. To reach this end, quasiparticle (QP) Debye mass depending upon baryonic chemical potential ( μ b ) and temperature has been employed, and hence the variation of differential scattering cross-section with baryonic chemical potential and temperature at fixed value of the scattering angle (θ = 9 0 o ) has been studied. The variation of differential scattering cross-section with scattering angle θ (in degree) at fixed temperature and baryonic chemical potential has also been studied. We have also studied the effect of impact parameter and transverse momentum on differential scattering cross-section at θ = 90 o . [ABSTRACT FROM AUTHOR]

Numerous resonances in the c c ¯ and 4q systems, containing c c ¯ plus s s ¯ quarks (or light q q ¯ ) were observed during last decades and recently the LHCb has found a remarkable narrow peak T cc (3875) in the D D ∗ system. Besides there are several highly excited charmonium-like resonances, which can be treated as the shifted standard charmonium states. We analyze all these groups of the resonances in the mass region (3900–4700) MeV, using relativistic strong coupling theory with possible channel coupling phenomena. For the shifted charmonium states conventional charmonium spectrum is presented, being calculated with the relativistic string Hamiltonian, which does not contain fitting parameters, while for high excitations the universal flattened confining potential is used. It is shown that X(4274), X(4500), X(4700) can be identified as 3 3 P 1 , 4 3 P 0 , 5 3 P 0 states. The group of exotic states are considered using the Extended Recoupling Model, where two mesons m 1 , m 2 transfer into another pair of mesons m 3 , m 4 and back (infinite number of times), creating the four-quark resonance. Within this approach the resonances – T cc (3875) , Z c (3900) , X (3915) , Z cs (3985) , X (4014) , and X(4140) – can be explained as the exotic four-quark states in the S-wave decay channels. [ABSTRACT FROM AUTHOR]

In the fractional nonrelativistic potential model, the decomposition of heavy quarkonium in a hot magnetized medium is investigated. The analytical solution of the fractional radial Schrodinger equation for the hot-magnetized ¨ interaction potential is displayed by using the conformable fractional Nikiforov-Uvarov method. Analytical expressions for the energy eigenvalues and the radial wave function are obtained for arbitrary quantum numbers. Next, we study the charmonium and bottmonium binding energies for different values of the magnetic field in the thermal medium. The effect of the fractional parameter on the decomposition temperature is also analyzed for charmonium and bottomonium in the presence of hot magnetized media. We conclude that the dissociation of heavy quarkonium in the fractional nonrelativistic potential model is faster than the classical nonrelativistic potential model. [ABSTRACT FROM AUTHOR]

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In this work, we perform a detailed study of transition form factors for axial- vector meson production via the two-photon fusion process γ*γ* → 1++, with space-like virtual photons in the initial state and a P-wave axial-vector quarkonium in the final state. In this analysis, we employ the formalism of light-front quarkonium wave functions obtained from a solution of the Schrödinger equation for a selection of interquark potentials for Q Q ¯ interaction. We found the helicity structure and covariant decomposition of the matrix elements that can be generically applied for any q q ¯ axial-vector meson γ*γ* → 1++ transition, while our numerical results are given for the phenomenologically relevant charmonium χc1 state. We present the helicity form factors as functions of both photon virtualities. We also obtain, that QFLT(Q2, 0)/FTT(Q2, 0) = const. [ABSTRACT FROM AUTHOR]

The polarizations of prompt and non-prompt ▪ and ψ (2S) mesons are measured in proton-proton collisions at s = 13 TeV, using data samples collected by the CMS experiment in 2017 and 2018, corresponding to a total integrated luminosity of 103.3 fb − 1. Based on the analysis of the dimuon decay angular distributions in the helicity frame, the polar anisotropy, λ ϑ , is measured as a function of the transverse momentum, p T , of the charmonium states, in the 25–120 and 20–100 GeV ranges for the ▪ and ψ (2S) , respectively. The non-prompt polarizations agree with predictions based on the hypothesis that, for p T ≳ 25 GeV , the non-prompt ▪ and ψ (2S) are predominantly produced in two-body B meson decays. The prompt results clearly exclude strong transverse polarizations, even for p T exceeding 30 times the ▪ mass, where λ ϑ tends to an asymptotic value around 0.3. Taken together with previous measurements, by CMS and LHCb at s = 7 TeV, the prompt polarizations show a significant variation with p T , at low p T. [ABSTRACT FROM AUTHOR]

We report the p + p and p + d differential cross sections measured in the SeaQuest experiment for J / ψ and ψ (2 S) production at ▪ beam energy covering the forward x -Feynman (x F) range of 0.5 < x F < 0.9. The measured cross sections are in good agreement with theoretical calculations based on the nonrelativistic QCD (NRQCD) using the long-distance matrix elements deduced from a recent global analysis of proton- and pion-induced charmonium production data. The σ ψ (2 S) / σ J / ψ cross section ratios are found to increase as x F increases, indicating that the q q ¯ annihilation process has larger contributions in the ψ (2 S) production than the J / ψ production. The σ p d / 2 σ p p cross section ratios are observed to be significantly different for the Drell-Yan process and J / ψ production, reflecting their different production mechanisms. We find that the σ p d / 2 σ p p ratios for J / ψ production at the forward x F region are sensitive to the d ¯ / u ¯ flavor asymmetry of the proton sea, analogous to the Drell-Yan process. The transverse momentum (p T) distributions for J / ψ and ψ (2 S) production are also presented and compared with data collected at higher center-of-mass energies. [ABSTRACT FROM AUTHOR]

In this research, we model Hulthén plus generalized inverse quadratic Yukawa potential to interact in a quark-antiquark system. The solutions of the Schrödinger equation are obtained using the Nikiforov-Uvarov method. The energy spectrum and normalized wave function were obtained. The masses of the heavy mesons for different quantum states such as 1S, 2S, 1P, 2P 3S, 4S, 1D, and 2D were predicted as 3.096 GeV, 3.686 GeV, 3.327 GeV, 3.774GeV, 4.040 GeV, 4.364GeV, 3.761 GeV, and 4.058 GeV respectively for charmonium (cc). Also, for bottomonium (bb) we obtained 9.460 GeV, 10.023 GeV, 9.841 GeV, 10.160 GeV, 10.345 GeV, 10.522 GeV, and 10.142GeV for different states of 1S, 2S, 1P, 2P, 3S, 4S, 1D respectively. The partition function was calculated from the energy spectrum, thereafter other thermal properties were obtained. The results obtained showed an improvement when compared with the work of other researchers and excellently agreed with experimental data with a percentage error of 1.60 % and 0.46 % for (cc) and (bb), respectively. [ABSTRACT FROM AUTHOR]

In the wake of recent measurements of ratios of semileptonic branching fractions: R J / ψ , R D and R D ∗ reported by the LHCb, BELLE and HFLAV Collaborations, we calculate invariant form factors for the exclusive semileptonic B c -meson decays to radially excited charmonium and charm meson states in the full kinematical region within the framework of relativistic independent quark (RIQ) model. We evaluate the lepton mass effect in the decay processes induced by b → c , u transition at the quark level. Our predictions on branching fractions for B c → η c / ψ (n S) are found ∼ 10 - 2 - 10 - 4 and that for B c → D ∗ (n S) are ∼ 10 - 4 in their e - decay modes, which lie within the detection accuracy of current experiment. Our predictions on branching fractions, forward backward asymmetry and asymmetry parameter are found in reasonable agreement with other model predictions; which can hopefully be tested in future experiments at LHC and Tevatron. Our predicted observable R in this sector are found comparable to other standard model (SM) predictions that violate the lepton flavor universality hinting at new physics beyond SM. [ABSTRACT FROM AUTHOR]

The most precise measurement of decay-time-dependent CP violation in the decays of B 0 → J / ψ K S 0 and B 0 → ψ (2 S) K S 0 was reported by LHCb collaboration with the values of S J / ψ K S 0 = 0. 8 3 ± 0. 0 8 ± 0. 0 1 , C J / ψ K S 0 = 0. 1 2 ± 0. 0 7 ± 0. 0 2 and S ψ (2 S) K S 0 = 0. 8 4 ± 0. 1 0 ± 0. 0 1 , C ψ (2 S) K S 0 = − 0. 0 5 ± 0. 1 0 ± 0. 0 1. In this study, the parameters of CP violation in these decay modes have been calculated under the factorization approach. In these decays, CP violation in the interference of mixing and decay has has arisen from decay-time-dependent asymmetry. This type of CP violation has been characterized by Im λ f ≠ 0. We have estimated the parameters of S J / ψ K S 0 = 0. 8 8 ± 0. 0 0 and C J / ψ K S 0 = 0. 1 1 ± 0. 0 1 for the B 0 → J / ψ K S 0 decay and S ψ (2 S) K S 0 = 0. 8 9 ± 0. 0 1 and C ψ (2 S) K S 0 = − 0. 0 4 ± 0. 0 2 correspond to the B 0 → ψ (2 S) K S 0 decay which are compatible with the experimental values approved by the LHCb collaboration. In the following, we have obtained the value of sin 2 β. Finally, we have calculated the total amplitude and obtained comparable results with the experimental values for the branching ratios of both decays. [ABSTRACT FROM AUTHOR]

The Born cross sections of the e+e−→ D*+D*− and e+e−→ D*+D− processes are measured using e+e− collision data collected with the BESIII experiment at center-of-mass energies from 4.085 to 4.600 GeV, corresponding to an integrated luminosity of 15.7 fb−1. The results are consistent with and more precise than the previous measurements by the Belle, Babar and CLEO collaborations. The measurements are essential for understanding the nature of vector charmonium and charmonium-like states. [ABSTRACT FROM AUTHOR]

A search for the decay B0→ ϕμ+μ− is performed using proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV collected by the LHCb experiment and corresponding to an integrated luminosity of 9 fb−1. No evidence for the B0→ ϕμ+μ− decay is found and an upper limit on the branching fraction, excluding the ϕ and charmonium regions in the dimuon spectrum, of 4.4 × 10−3 at a 90% credibility level, relative to that of the B s 0 → ϕμ+μ− decay, is established. Using the measured B s 0 → ϕμ+μ− branching fraction and assuming a phase-space model, the absolute branching fraction of the decay B0→ ϕμ+μ− in the full q2 range is determined to be less than 3.2 × 10−9 at a 90% credibility level. [ABSTRACT FROM AUTHOR]

A search for the decay B0→ ϕμ+μ− is performed using proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV collected by the LHCb experiment and corresponding to an integrated luminosity of 9 fb−1. No evidence for the B0→ ϕμ+μ− decay is found and an upper limit on the branching fraction, excluding the ϕ and charmonium regions in the dimuon spectrum, of 4.4 × 10−3 at a 90% credibility level, relative to that of the B s 0 → ϕμ+μ− decay, is established. Using the measured B s 0 → ϕμ+μ− branching fraction and assuming a phase-space model, the absolute branching fraction of the decay B0→ ϕμ+μ− in the full q2 range is determined to be less than 3.2 × 10−9 at a 90% credibility level. [ABSTRACT FROM AUTHOR]

The excitation energy spectra of heavy baryons consisting of a heavy quark and two light quarks are investigated using diquark models in order to examine the nature of the diquark as a constituent of single heavy baryons. We consider two diquark models; in Model A the diquark is treated as a point-like particle, while it has a spatial size in Model B. We determine the masses of scalar and axial vector diquarks by the mass difference of the ground-state charmed baryons and the Λ c baryon, while the mass of the ud scalar diquark in the Λ c baryon is assumed to be 500 MeV as a reference. The parameters of these models are fixed by the 1 p excitation energy of Λ c . We find that Model A reproduces well the excitation energy spectra of the charmed and bottomed baryons, although the string tension of the confinement potential in Model A should be half of that of the charmonium, while Model B suggests degeneracy of the 2 s and 1 d states, which is not seen in the Λ c spectrum. [ABSTRACT FROM AUTHOR]

A study of B+→ J/ψηK+ decays, followed by J/ψ → μ+μ− and η → γγ, is performed using a dataset collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The J/ψη mass spectrum is investigated for contributions from charmonia and charmonium-like states. Evidence is found for the B+→ (ψ2(3823) → J/ψη)K+ and B+→ (ψ(4040) → J/ψη)K+ decays with significance of 3.4 and 4.7 standard deviations, respectively. This constitutes the first evidence for the ψ2(3823) → J/ψη decay. [ABSTRACT FROM AUTHOR]

We study the internal structure of a range of four-quark states with charm quark contributions using a two-body Bethe–Salpeter equation. Thereby, we examine charmonium-like states with hidden charm and quark content c c ¯ q q ¯ , open-charm states with quark content c c q ¯ q ¯ and all-charm states with c c c ¯ c ¯ . In particular we study the internal competition between meson–meson components and diquark–antidiquark components in the wave functions of these states. Our results indicate that the χ c 1 (3872) and the Z c (3900) are predominantly D D ¯ ∗ states and that the recently discovered open-charm state T cc + is dominated by an internal D D ∗ component. In both cases the diquark components are negligible. For the all-charm state X(6900) with as yet unknown quantum numbers we identify candidates in the excitation spectra of 0 + and 1 + states. Furthermore, our framework serves to provide predictions for further, yet undiscovered open and hidden charm four-quark states. [ABSTRACT FROM AUTHOR]

In recent years there was significant progress in the B-physics studies including those at the Large Hadron Collider (LHC). This report will focus on two recent results in B-physics from the CMS collaboration. [ABSTRACT FROM AUTHOR]