The properties of the X(3872) and its spin partner, the X(4014), are studied both in vacuum and at finite temperature. Using an effective hadron theory based on the hidden-gauge Lagrangian, the X(3872) is dynamically generated from the s-wave rescattering of a pair of pseudoscalar and vector charm mesons. By incorporating the thermal spectral functions of open charm mesons, the calculation is extended to finite temperature. Similarly, the properties of the X(4014) are obtained out of the scattering of charm vector mesons. By applying heavy-quark flavor symmetry, the properties of their bottom counterparts in the axial-vector and tensor channels are also predicted. All the dynamically generated states show a decreasing mass and acquire an increasing decay width with temperature, following the trend observed in their meson constituents. These results are relevant in relativistic heavy-ion collisions at high energies, in analyses of the collective medium formed after hadronization, or in femtoscopic studies, and can be tested in lattice-QCD calculations exploring the melting of heavy mesons at finite temperature.

This research has been supported from the Projects No. CEX2019-000918-M, No. CEX2020-001058-M (Unidades de Excelencia “María de Maeztu”), No. PID2019–110165GB-I00, and No. PID2020–118758GB-I00, financed by the Spanish Grant No. MCIN/AEI/10.13039/501100011033, as well as by the EU STRONG-2020 project, under the program H2020-INFRAIA-2018-1 Grant Agreement No. 824093. G. M. acknowledges support from the FPU17/04910 Doctoral Grant from the Spanish Ministerio de Universidades, and U.S. DOE Contract No. DE-AC05-06OR23177, under which Jefferson Science Associates, LLC, operates Jefferson Lab. L. T. and J. M. T.-R. acknowledge support from the DFG through Projects No. 411563442 (Hot Heavy Mesons) and No. 315477589-TRR 211 (Strong-interaction matter under extreme conditions). L. T. also acknowledges support from the Generalitat Valenciana under Contract No. PROMETEO/2020/023.

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000918-M).

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2020-001058-M).

Funded by SCOAP3.

Peer reviewed