Related papers: Zero mode effect in the $1^{-+}$ four quark states

The QCD sum rule technique is employed to investigate pentaquark states with strangeness S = +1 and IJ^P = 0,1/2^\pm, 1,1/2^\pm, 0,3/2^\pm, 1,3/2^\pm. Throughout the calculation, emphasis is laid on the establishment of a valid Borel…

We construct an equation of state including the hadron-quark phase transition. The mixed phase is obtained by the Gibbs conditions for finite temperature. We adopt the equation of state based on the relativistic mean field theory for the…

The masses of the flavor octet and singlet baryons with negative parity and spin 1/2 are calculated using the QCD sum rule. We find that the chiral symmetry breaking vacuum condensates cause the mass splitting of the positive and negative…

In this article, we construct the six-quark currents with the $J^P=0^+$, $0^-$, $1^+$ and $1^-$ to study the $\Lambda_c$$\Lambda_c$ dibaryon and $\Lambda_c$$\bar{\Lambda}_c$ baryonium states via QCD sum rules. We consider the vacuum…

The claim that the light quark mass ratio (m_d - m_u)/m_s can be extracted from the decay width ratio Gamma(eta' -> pi^0 pi^+ pi^-)/Gamma(eta' -> eta pi^+ pi^-) is critically investigated within a U(3) chiral unitary framework. The…

Using ratios of the inverse Laplace transform sum rules within stability criteria for the subtraction point \mu in addition to the ones of the usual tau spectral sum rule variable and continuum threshold t_c, we extract the \pi(1300) and…

The up and down quark masses are determined from an optimized QCD Finite Energy Sum Rule (FESR) involving the correlator of axial-vector divergences, to five loop order in Perturbative QCD (PQCD), and including leading non-perturbative QCD…

The pentaquark state recently discovered has been studied with three quark models which either fit the nucleon spin structure or the $NN$ scattering. A minimum $\Theta^+$ mass of 1620 MeV is obtained both for the ${1/2}^\pm$ state. The…

We discuss properties of 1^{-+} exotic mesons within the framework of the QCD field-theoretic approach. We estimate the mass of the lowest-lying 1^{-+} exotic meson using renormalization-improved QCD sum rules, and find that the mass lies…

The pentaquark state of $\Theta^{+}(uudd\bar{s})$ has been observed to decay with two decay modes: $\Theta^+\to n K^+$ and $\Theta^+ \to p K^0$. The decay probability ratio of the two decay modes is studied with general symmetry…

We systematically investigate the mass spectra of $\{Q\bar{s}\}\{\bar{Q}^{(')}s\}$ molecular states in the framework of QCD sum rules. The interpolating currents representing the molecular states are proposed. Technically, contributions of…

In this article, we assume that there exists a scalar hidden charm tetraquark state in the $\pi^+ \chi_{c1}$ invariant mass distribution, and study its mass using the QCD sum rules. The numerical result $M_{Z}=(4.36\pm0.18) \rm{GeV}$ is…

We calculate the coupling constants, $g_{\pi NS_{11}}$ and $g_{\eta NS_{11}}, using QCD sum rules in the presence of an external meson field. A covariant derivative is introduced within the S_{11} interpolating field so that in the…

We study $e^{+}e^{-}$ collisions with a $\pi^{+}\pi^{-}\pi^{0}\eta_{c}$ final state using data samples collected with the BESIII detector at center-of-mass energies $\sqrt{s}=4.226$, $4.258$, $4.358$, $4.416$, and $4.600$ GeV. Evidence for…

We present new compact integrated expressions of QCD spectral functions of heavy-light molecules and four-quark $XYZ$-like states at lowest order (LO) of perturbative (PT) QCD and up to $d=8$ condensates of the Operator Product Expansion…

Three different ways of determining the strange quark mass using QCD sum rules are reviewed. First, from a QCD sum rule determination of the up and down quark masses, together with the current algebra ratio $ m_{s}/(m_{u}+m_{d})$. Second…

In previous work it has been shown that, either from a sum rule for the subleading Isgur-Wise function $\xi_3(1)$ or from a combination of Uraltsev and Bjorken SR, one infers for $P$-wave states $|\tau_{1/2}(1)| \ll |\tau_{3/2}(1)|$. This…

In this article, we assume that there exist hidden charmed tetraquark states with the spin-parity $J^P=1^-$, and calculate their masses with the QCD sum rules. The numerical result indicates that the masses of the vector hidden charmed…

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 $\Theta^+ (1540)$…

In this article, we recalculate the contributions of all vacuum condensates up to dimension-6, in particular the one-loop corrections to the quark condensates $\alpha_s<\bar{q}q>$ and partial one-loop corrections to the four-quark…