QCD sum rules on the complex Borel plane

Heavy meson spectroscopy under strong magnetic field

“…Although it might be usually difficult to extract the higher-energy structures except for the ground state from QCD sum rules and lattice QCD simulations, phenomenological estimation as constructed by Refs. [75,76] and some numerical techniques such as the maximum entropy method [93][94][95] could be useful to investigate excited states and crossing structures in hadronic spectral functions under finite magnetic field. Furthermore, the spectral function for vector channels can be related to the experimental dilepton spectra (e.g.…”

Measuring the Strangeness Content of the Nucleon by Observing the ϕ-Meson Mass Shift in Nuclear Matter

“…Firstly, the twist-4 contributions to the OPE at dimension 6 are not properly taken into account at present and it would therefore be worth to study them in detail. Furthermore, the MEM extraction could still be improved by a recently formulated sum rules which makes use of complex Borel masses [22]. Moreover, we have studied the φ-meson only at rest in this work, while in an experimental setting the φ always carries a finite amount of momentum, which should in principle be taken into account.…”

Charmonium ground and excited states at finite temperature from complex Borel sum rules

“…For the determination of the upper boundary, we employ an improved scheme as follows. In the originally proposed scheme [47], we employed a simple circular boundary on the complex Borel mass plane, whose radius M 2 r is treated as a free parameter as follows: M 2 < M 2 r , where M 2 = M 2 e iθ . However, it includes the region θ ∼ π 2 , where the damping by the kernels becomes weaker, as 2 This method of setting the lower boundaries was proposed in the first analysis using CBSR with MEM [47].m c(mc)…”

“…Although MEM for QCD sum rules is a powerful tool to investigate the structure of spectral function, which has already been applied to various systems [33,34,[41][42][43][44][45][46], it was difficult to reproduce the second peak with statistical significance from Borel sum rules. However, by using the combination of QCD sum rules on the complex Borel plane (CBSR) and MEM, it has recently become possible to extract excited states due to the improved resolution [47]. In Ref.…”