Thermal QCD sum rules study of vector charmonium and bottomonium states

Abstract

We calculate the masses and leptonic decay constants of the heavy vector quarkonia, J/ψ and Υ mesons at finite temperature. In particular, considering the thermal spectral density as well as additional operators coming up at finite temperature, the thermal QCD sum rules are acquired. Our numerical calculations demonstrate that the masses and decay constants are insensitive to the variation of temperature up to T ∼ = 100 M eV , however after this point, they start to fall altering the temperature. At deconfinement temperature, the decay constants attain roughly to 45% of their vacuum values, while the masses are diminished about 12%, and 2.5% for J/ψ and Υ states, respectively. The obtained results at zero temperature are in good consistency with the existing experimental data as well as predictions of the other nonperturbative models. Considerable decreasing in the values of the decay constants can be considered as a sign of the quark gluon plasma phase transition.

Improved Hilbert moment thermal QCD sum rules for B_s meson and stability with respect to moment parameter

“…These results are in good agreement with the existing experimental data m Bs = 5.36677 ± 0.00024 GeV [26], with predictions of other nonperturbative models [13][14][15][16] (for more details, see [2]) and with lattice QCD calculations m Bs = 5.385 ± 0.044 GeV, f Bs = 0.253 ± 0.015 GeV [27]. We also make an error analysis to understand the sensitivity of obtained results to uncertainties on the continuum threshold and quark and gluon condensates.…”

$$ B_c B_c J/\psi $$ B c B c J / ψ

“…In the calculations, thermal versions of some parameters such as the continuum thresholds and the vacuum condensates are used. Temperature-dependent masses and decay constants are obtained in [26,27] by using the thermal QCD sum rules approach. The values of the masses at T = 0 are calculated as m J/ψ = (3.05 ± 0.08) and m B c = (6.37 ± 0.05) GeV, which values are in very good agreement with the experimental data.…”

“…This extension is based on two basic assumptions: that the Operator Product Expansion (OPE) and the notion of quark-hadron duality remain valid at finite temperature, but the vacuum condensates must be replaced by their thermal expectation values [14][15][16][17]. The thermal QCD sum rules approach has been extensively used for studying the masses and decay constants of both light and heavy mesons as a reliable and wellestablished method [14][15][16][17][18][19][20][21][22][23][24][25][26][27]. But in the literature there are few theoretical works devoted to the analysis of the hadron vertex form factors at finite temperature.…”

“…In order to calculate the form factors, one must have the temperature dependencies of the masses and decay constants of the hadrons in the vertex. Since we aim to extend the strong form factors to finite temperatures, in this study, we choose mesons whose masses and leptonic decay constants have been investigated in a thermal QCD sum rules approach [26,27].…”

Study ofχc01P→J/ψγandχBashiry1 2014Advances in High Energy Physics1010View full textAdd to dashboardCite

“…Heavy quarkonium states can have many bound states and decay channels used to study and determine different parameters of standard model (SM) and QCD from the theoretical perspective. In particular, the calculation of bottomonium masses [3], total widths, coupling constants [4][5][6][7], and branching ratio can serve as benchmarks for the low energy predictions of QCD. In addition, the theoretical calculations on the branching ratio of radiative decays of heavy quarkonium states are relatively clean with respect to the hadronic or semileptonic decays, and their comparison with experimental data could provide important insights into their nature and hyperfine interaction.…”