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Bruschini, R., & Gonzalez, P. (2021). Diabatic description of bottomoniumlike mesons. Phys. Rev. D, 103(11), 114016–13pp.
Abstract: We apply the diabatic approach, specially suited for a QCD based study of conventional (quark-antiquark) and unconventional (quark-antiquark + meson-meson) meson states, to the description of hidden-bottom mesons. A spectral analysis of the I = 0, J(++) and 1(--) resonances with masses up to about 10.8 GeV is carried out. Masses and widths of all the experimentally known resonances, including conventional and unconventional states, can be well reproduced. In particular, we predict a significant B (B) over bar* component in Upsilon(10580). We also predict the existence of a not yet discovered unconventional 1(++) narrow state, with a significant B-s(B) over bar (s)* content making it to decay into Upsilon(1S)phi, whose experimental discovery would provide definite support to our theoretical analysis.
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Bruschini, R., & Gonzalez, P. (2021). Coupled-channel meson-meson scattering in the diabatic framework. Phys. Rev. D, 104(7), 074025–16pp.
Abstract: We apply the diabatic framework, a QCD-based formalism for the unified study of quarkoniumlike systems in terms of heavy quark-antiquark and open-flavor meson-meson components, to the description of coupled-channel meson-meson scattering. For this purpose, we first introduce a numerical scheme to find the solutions of the diabatic Schrodinger equation for energies in the continuum, then we derive a general formula for calculating the meson-meson scattering amplitudes from these solutions. We thus obtain a completely nonperturbative procedure for the calculation of open-flavor meson-meson scattering cross sections from the diabatic potential, which is directly connected to lattice QCD calculations. A comprehensive analysis of various elastic cross sections for open-charm and open-bottom meson-meson pairs is performed in a wide range of the center-of-mass energies. The relevant structures are identified, showing a spectrum of quasiconventional and unconventional quarkoniumlike states. In addition to the customary Breit-Wigner peaks, we obtain nontrivial structures such as threshold cusps and minimums. Finally, our results are compared with existing data and with results from our previous bound-state-based analysis, finding full compatibility with both.
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Bruschini, R., & Gonzalez, P. (2020). Radiative decays in charmonium beyond the p/m approximation. Phys. Rev. D, 101(1), 014027–16pp.
Abstract: We analyze the theoretical description of radiative decays in charmonium. We use an elementary emission decay model to build the most general electromagnetic transition operator. We show that accurate results for the widths can be obtained from a simple quark potential model reasonably fitting the spectroscopy if the complete form of the operator is used instead of its standard p/m approximation and the experimental masses are properly implemented in the calculation.
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Bruschini, R., & Gonzalez, P. (2020). Diabatic description of charmoniumlike mesons. Phys. Rev. D, 102(7), 074002–19pp.
Abstract: We apply the diabatic formalism, first introduced in molecular physics, to the description of heavy-quark mesons. In this formalism the dynamics is completely described by a diabatic potential matrix whose elements can be derived from unquenched lattice QCD studies of string breaking. For energies far below the lowest open flavor meson-meson threshold, the resulting diabatic approach reduces to the well-known Born-Oppenheimer approximation where heavy-quark meson masses correspond to energy levels in an effective quark-antiquark potential. For energies close below or above that threshold, where the Born-Oppenheimer approximation fails, this approach provides a set of coupled Schrodinger equations incorporating meson-meson components nonperturbatively, i.e., beyond loop corrections. A spectral study of heavy mesons containing c (c) over bar with masses below 4.1 GeV is carried out within this framework. From it a unified description of conventional as well as unconventional resonances comes out.
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Bruschini, R., & Gonzalez, P. (2019). Quark model description of psi(4260). Phys. Rev. C, 99(4), 045205–9pp.
Abstract: From lattice indications we follow a Born-Oppenheimer approximation to build a quark-antiquark static potential for J(Pc) = 1(--) charmonium states below their first S-wave meson-meson threshold. We show that a good description of the mass and decay properties of the experimentally well established psi(4260) resonance is feasible.
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