A note on the QCD vacuum tensor susceptibility

Abstract

We consider the procedure of determination of induced quark condensates in the QCD sum rule approach. It is noted that the previous estimations of this value were very rough. It is shown, that the detailed analyses of this parameter of QCD vacuum leads to the conclusion that the value of the tensor susceptibility has opposite sign and much larger than estimations which were obtained before. The reason of this contradiction is discussed. It is noted that naive ways of determination of induced condensates may lead to wrong results. The case of tensor susceptibility is the example demonstrating the importance of the procedure which is applied for calculation of such condensates. New results for the nucleon tensor charge are presented. The tensor charge is related to the first moment of the transversity distribution function h 1 (x).

New shapes of light-cone distributions of the transversely polarized $\rho$ -mesons

“…The limit of these expressions to the standard (local) contributions Here µ 2 ∼ 1 GeV 2 corresponds to the average value of the Borel parameter M 2 in the stability window; α s 1GeV 2 ≈ 0.52. We also use the 'mixed' perturbative spectral density suggested in [31] in the "mixed" SR: …”

Progress in vacuum susceptibilities and their applications to the chiral phase transition of QCD

“…In the QCD sum rules external field formula, QCD vacuum susceptibilities play important roles in determining the hadron properties [2,3,5,6]. For example, the strong and parity-violating pion-nucleon coupling depends crucially upon the vacuum susceptibilities of pion [7,8], and the tensor vacuum susceptibility is closely related to the tensor charge of nucleon [9,10,11,12,13,14,15,16,17]. The nonlinear susceptibilities are also found to be correlated with the cumulant of baryon-number fluctuations in experiments [18,19,20,21,22].…”

Calculation of Tensor Susceptibility Beyond Rainbow-Ladder Approximation

“…In particular, tensor vacuum susceptibility is relevant for the determination of the tensor charge of the nucleon in the QCD sum rule approach [4]. The previous calculations of the tensor vacuum susceptibility have shown that the theoretical treatment of this quantity is subtle and different treatments can lead to different results [5][6][7][8][9]. In order to get a reliable theoretical prediction of the tensor charge, one needs to determine the tensor vacuum susceptibility as precisely as possible.…”