On the strong coupling N(*)N(*) $\pi$

Abstract

We study the strong vertices N * N π, N * N * π and N N π in QCD, where N * denotes the negative parity N (1535) state. We use the most general form of the interpolating currents to calculate the corresponding strong coupling constants. It is obtained that the coupling associated to N * N π vertex is strongly suppressed compared to those related to two other vertices. The strong coupling corresponding to N * N * π is obtained to be roughly half of that of N N π vertex. We compare the obtained results on N * N π and N N π vertices with the existing predictions of other theoretical studies as well as those extracted from the experimental data.

Dmeson mass increase by restoration of chiral symmetry in nuclear matter

“…As a result, an opposite mass shift of +45 MeV at ρ 0 was obtained, however, with a significant ambiguity from phenomenological density dependence of the threshold parameter. Recent new analyses [21,22] support the conclusions of [19]. The results of the present paper, obtained by applying the MEM to the QCD sum rules, are independent of uncertainties from phenomenological functional forms and its threshold parameter.…”

“…In this section, we compare our results with those of previous works, which are summarized in Table II. We in particular will comment and shortly discuss the results of the in-medium D meson masses from QCD sum rules [19][20][21][22]. In Ref.…”

“…The approaches of Refs. [19,21,22] relate the spectral function to the forward D-N scattering amplitude in the limit of vanishing three-momentum [31]. In this method, the vacuum and in-medium parts of the…”

“…The Borel windows in Refs. [21] and [22] correspond to 2.00 GeV < M < 2.83 GeV and 2.10 GeV < M < 2.32 GeV, respectively. On the other hand, in Ref.…”

“…There are furthermore results from a chiral SU (3) model extended to SU (4) [11][12][13][14] and a pion exchange model betweenD and N [15]. The second approach includes the quarkmeson coupling (QMC) model [16,17] and QCD sum rules [18][19][20][21][22]. Among all these, only QCD sum rules are directly based on QCD.…”