scholarly journals Lepton polarization asymmetries for FCNC decays of the Λb baryon

2015 ◽  
Vol 30 (27) ◽  
pp. 1550172 ◽  
Author(s):  
L. Mott ◽  
W. Roberts

Branching ratios, lepton forward–backward asymmetries, and lepton polarization asymmetries for the flavor-changing neutral current (FCNC) dileptonic decays of the [Formula: see text] baryon to the ground state and a number of excited state [Formula: see text] baryons are calculated using form factors extracted using wave functions from a constituent quark model. The SM branching ratios for the transition to the ground state calculated using these quark model form factors are consistent with the recent measurement reported by the LHCb collaboration. It is shown that the lepton polarization asymmetries are largely insensitive to the transition form factors and, therefore, may also be insensitive to the effects of QCD in the nonperturbative regime. These observables could therefore provide somewhat model independent ways of extracting various combinations of the Wilson coefficients.

2007 ◽  
Vol 76 (6) ◽  
Author(s):  
M. De Sanctis ◽  
M. M. Giannini ◽  
E. Santopinto ◽  
A. Vassallo

2010 ◽  
Vol 25 (24) ◽  
pp. 2077-2088 ◽  
Author(s):  
W. ZHENG ◽  
H. R. PANG

In the framework of constituent quark model, mass spectra of the ground-state baryons consisting of three or two heavy (b or c) and one light (u, d or s) quarks are calculated by solving three-body Faddeev equations. The results imply that, it is possible to obtain a unified model to describe heavy baryons spectra, as well as meson and SU(3) octet and decuplet baryon spectra. We find that, when taking into account the relativistic correction quark–diquark approximation and three-body Faddeev approach tend to give similar predictions for heavy–light systems. We also study the spin splitting of JP = (1/2+) and JP = (3/2+).


Author(s):  
Qi-Fang Lü ◽  
Dian-Yong Chen ◽  
Yu-Bing Dong

AbstractInspired by recent measurement of possible fully charmed tetraquarks in LHCb Collaboration, we investigate the mass spectra of fully heavy tetraquarks $$QQ {\bar{Q}} {\bar{Q}}$$ Q Q Q ¯ Q ¯ in an extended relativized quark model. Our estimations indicate that the broad structure around 6.4 GeV should contain one or more ground states for $$cc {\bar{c}} {\bar{c}}$$ c c c ¯ c ¯ tetraquarks, while the narrow structure near 6.9 GeV can be categorized as the first radial excitation of $$cc {\bar{c}} {\bar{c}}$$ c c c ¯ c ¯ system. Moreover, with the wave functions of the tetraquarks and mesons, the strong decays of tetraquarks into heavy quarkonium pair are qualitatively discussed, which can be further checked by the LHCb and CMS Collaborations.


2005 ◽  
Vol 20 (08n09) ◽  
pp. 1914-1917
Author(s):  
Y. B. DONG

The recent measurement of quark-hadron duality is shortly discussed by using a simple constituent quark model. Comparing with the moments of the structure functions in the resonance region and in the deep inelastic scattering region, we study the occurances of Bloom-Gilman quark-hadron duality for the nucleon structure function F2 and g1. Local duality is also analyzed.


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