Mass and width of strange baryon resonances using QCD sum rules

Abstract

The mass spectra of strange baryons in the octet family are investigated in a finite0energy QCD sum rule approach based on the Gauss-Weierstrass transform. The phenomenological form of the spectral function is saturated by the ground state and two of the lowest excited states, considered as having opposite parities. Treating the ground state parameters as known, the masses, widths and couplings to the interpolating fields are determined and compared to experiment.

Pion couplings with low-lying nucleon resonances

“…( 12) and separate its odd and even parts. It is usual to model the continuum part of Π(q, p) ph by Π(q, p) OP E with q 2 0 > s π , a threshold parameter and only terms with postive powers of q 0 are taken into account in doing so [5,8,14,17,15,16]. The parameters δ 2 and C 2 are defined as [19,20,21] 0|qg Gµν…”

“…While the phenomenological Lagrangians are good for a broad understanding of hadronic interactions, QCD based approaches give a microscopic view of hadronic interaction and provide a test of QCD at low energies. QCD-based methods have been applied, in past, to determine the masses and widths of nucleon resonances [5,6,7] and other light baryon resonances [8]. In recent past, these methods have also been applied to calculate coupling constant of a pion with a nucleon resonance [9,10,11,12,13].…”

Double Pole Method in QCD Sum Rules for Vector Mesons

“…In general, by QCDSR, the excited states are studied in "pole + pole + continuum" ansatz with Q 2 ¼ 0 [1,2], as we can see in the spectral sum [7], the Maximum Entropy [8] and Gaussian Sum Rule with "pole + pole + continuum" ansatz [9] approaches. There are studies on the ρ(1S, 2S) mesons [8,10,11], nucleons [7,12], ηc(1S, 2S) mesons [2], ψ(1S, 2S) mesons [1,13] and ϒ(1S, 2S) mesons [14]. In this paper, we obtain the ρ(1S, 2S) mesons masses and their decay constants taking the "pole + pole + continuum" ansatz in QCD sum rules,…”

The ρ(1S, 2S), ψ(1S, 2S), Υ(1S, 2S) and ψ t (1S, 2S) Mesons in a Double Pole QCD Sum Rule

“…There are studies on the ρ(1S, 2S) mesons [16,18,19], nucleons [15,20], η c (1S, 2S) mesons [2], ψ(1S, 2S) mesons [1,21] and Υ(1S, 2S) mesons [22]. In Gaussian Sum Rule is studied the mixed states of the glueballs and scalar mesons.…”

“…In QCDSR, the excited states are studied in: pole-pole plus continuum in Moment Sum Rule at Q 2 = 0 [1, 2], the spectral sum rules with pole-pole-pole plus continuum [15], the Maximum Entropy Method [16] and Gaussian Sum Rule with pole-pole plus continuum ansatz [17]. There are studies on the ρ(1S, 2S) mesons [16,18,19], nucleons [15,20], η c (1S, 2S) mesons [2], ψ(1S, 2S) mesons [1,21] and Υ(1S, 2S) mesons [22].…”