scholarly journals Single-particle spectral density of the unitary Fermi gas: Novel approach based on the operator product expansion, sum rules and the maximum entropy method

2015 ◽  
Vol 356 ◽  
pp. 467-497 ◽  
Author(s):  
Philipp Gubler ◽  
Naoki Yamamoto ◽  
Tetsuo Hatsuda ◽  
Yusuke Nishida
2020 ◽  
Vol 35 (14) ◽  
pp. 2050073
Author(s):  
Zhi-Gang Wang

In this paper, we construct the charmed-diquark–charmed-diquark–charmed-diquark-type current to study the axial vector triply-charmed hexaquark state with the QCD sum rules in details. In calculations, we take the energy scale formula [Formula: see text] to choose the pertinent energy scale of the QCD spectral density so as to enhance the pole contribution and improve the convergent behavior of the operator product expansion. If the spin-breaking effects are small for the triply-charmed hexaquark states, the ground state hexaquark states with [Formula: see text], [Formula: see text] and [Formula: see text] are estimated to have the masses about 5.8 GeV and narrow widths.


2019 ◽  
Vol 34 (19) ◽  
pp. 1950097 ◽  
Author(s):  
Zhi-Gang Wang

In this paper, we study the [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] pentaquark molecular states with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension [Formula: see text] in a consistent way. The present calculations support assigning the [Formula: see text] to be the [Formula: see text] pentaquark molecular state with [Formula: see text], assigning the [Formula: see text] to be the [Formula: see text] pentaquark molecular state with [Formula: see text], assigning the [Formula: see text] to be the [Formula: see text] pentaquark molecular state with [Formula: see text] or the [Formula: see text] pentaquark molecular state with [Formula: see text]. Special attention is paid to the operator product expansion.


2008 ◽  
Vol 23 (27n30) ◽  
pp. 2230-2233
Author(s):  
TORU KOJO ◽  
DAISUKE JIDO

The light scalar nonets are studied using the QCD sum rules for the tetraquark operators. The operator product expansion for the correlators is calculated up to dimension 12 and this enables us to perform analyses retaining sufficient pole-dominance. To classify the light scalar nonets, we investigate the dependence on current quark mass and flavor dynamics. Especially, to examine the latter, we study separately SU(3) singlet and octet states, and show that the number of annihilation diagrams is largely responsible for their differences, which is also the case even after the inclusion of the finite quark mass. Our results support the tetraquark picture for isosinglets, while that for octets is not conclusive yet.


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