相关论文: Exotic Hadron in Pole-dominated QCD Sum Rules

Borel transformed QCD sum rules conventionally use a real valued parameter (the Borel mass) for specifying the exponential weight over which hadronic spectral functions are averaged. In this paper, it is shown that the Borel mass can be…

The saturation of QCD chiral sum rules of the Weinberg-type is analyzed using ALEPH and OPAL experimental data on the difference between vector and axial-vector correlators (V-A). The sum rules exhibit poor saturation up to current energies…

We search for the strange pentaquark $\Theta^+$ using kaon interactions in the material of the Belle detector. No signal is observed in the $p K_S$ final state, while in the $p K^-$ final state we observe $\sim 1.6 \cdot 10^4$…

We use QCD sum rules to study the possible existence of $QQ-\bar{u}\bar{d}$ mesons, assumed to be a state with $J^{P}=1^{+}$. For definiteness, we work with a current with an axial heavy diquark and a scalar light antidiquark, at leading…

We construct QCD sum rules for nonperturbative studies without assuming the quark-hadron duality for the spectral density at low energy on the hadron side. Instead, both resonance and continuum contributions to the spectral density are…

We report on a study of the pentaquark Theta^+(1540), using a variety of different interpolating fields. We use Chirally Improved fermions in combination with Jacobi smeared quark sources to improve the signal and get reliable results even…

The newly observed $\Theta^+$ resonance is believed to be a pentaquark with the constituent quarks $uudd\bar s$. There are a few options for the constituent quark structure. Some advocate diquark-diquark-antiquark $(ud)$-$(ud)$-$\bar s$…

We investigate the static electromagnetic properties of three charm--strange molecular tetraquark candidates with quantum numbers $J^{P}=1^{+}$, namely the $D\bar{K}^{\ast}$, $D^{\ast}\bar{K}$, and $D^{\ast}\bar{K}^{\ast}$ systems. The…

We show that at certain values of QCD condensates the nucleon QCD sum rules with "pole+continuum" model for the hadron spectrum obtain an unphysical solution. This provides constrains for the values of condensates to be consistent with…

Recent results from H1, ZEUS, HERMES and HERA-B on searches for exotic baryons in ep collisions, eD scattering and pA scattering at HERA are reviewed. Evidence for the production of the strange pentaquark Theta^+ and of a narrow…

We have investigated negative-parity uudd\bar{s} pentaquarks by employing a quark model with the meson exchange and the effective gluon exchange as qq and q\bar{q} interactions. The system for the five quarks is dynamically solved; the…

In this article, we investigate the mass spectrum of the ground state hidden-charm tetraquark molecular states without strange, with strange and with hidden-strange via the QCD sum rules in a comprehensive way and revisit the assignments of…

A search for narrow Theta(1540)^+, a candidate for pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction p+C(N) \to Theta^+ \bar{K}^0 + C(N) on carbon nuclei or quasifree nucleons at…

We derive, in model independent way, the spin structure of the matrix element for the reaction of associative $\Theta^+$ pentaquark production, $\pi^{\pm}+D\to \Theta^+ +\Sigma^{\pm}, $ in the threshold region and in collinear kinematics.…

We estimate the mass of the pentaquark state with QCD sum rules and find that pentaquark states with isospin $I=0, 1, 2$ lie close to each other around $(1.55\pm 0.15)$ GeV. The experimentally observed baryon resonance $\Theta^+ (1540)$…

The difference of vector and axial-vector charged current correlators is analyzed by means of QCD sum rules. The contribution of 10-dimensional 4-quark condensates is calculated and its value is estimated within the framework of…

It is shown, that if the pentaquark $\Theta^+ = uudd\bar{s}$ baryon can be represented by the local quark current $\eta_{\Theta}$, its decay $\Theta^+ \to n K^+ (p K^0)$ is forbidden in the limit of chirality conservation. The…

We study the hidden-charm pentaquark states $udsc\bar{c}$ with spins 1/2, 3/2, and 5/2 within the QCD sum-rule approach. First, we construct the currents for the particular configuration of pentaquark states that consist of the flavor…

In this research, we tentatively assign the $T_{c\bar{s}}(2900)$ as the $A\bar{A}$-type tetraquark state, and study the mass spectrum of the tetraquark states with strange and doubly strange, which have the spin-parity $J^P = 0^+$, $1^+$…

The pion-baryon sigma terms and the strange-quark condensates of the octet and the decuplet baryons are calculated by employing the method of quantum chromodynamics (QCD) sum rules. We evaluate the vacuum-to-vacuum transition matrix…