scholarly journals Y(4260) and Y(4360) as mixed hadrocharmonium

2014 ◽  
Vol 29 (12) ◽  
pp. 1450060 ◽  
Author(s):  
Xin Li ◽  
M. B. Voloshin
Keyword(s):  
Heavy Quark ◽  
Reasonable Agreement ◽  
Light Quark ◽  
Spin Symmetry ◽  
Final States ◽  
Quark Spin ◽  
Spin Singlet ◽  
Heavy Quark Spin Symmetry ◽  
Spin Triplet ◽  
Heavy Quark Pair

Recent BESIII data indicate a significant rate of the process e+e- →hc π+ π- at the Y(4260) and Y(4360) resonances, implying a substantial breaking of the heavy quark spin symmetry. We consider these resonances within the picture of hadrocharmonium, i.e. of (relatively) compact charmonium embedded in a light-quark mesonic excitation. We suggest that the resonances Y(4260) and Y(4360) are a mixture, with mixing close to maximal, of two states of hadrochamonium, one containing a spin-triplet [Formula: see text] pair and the other containing a spin-singlet heavy quark pair. We argue that this model is in a reasonable agreement with the available data and produces distinctive and verifiable predictions for the energy dependence of the production rate in e+e- annihilation of the final states J/ψππ, ψ′ππ and hc ππ, including the pattern of interference between the two resonances.

HYPERFINE MIXING IN b → c SEMILEPTONIC AND ELECTROMAGNETIC DECAYS OF DOUBLY HEAVY bc BARYONS

2014 ◽  
Vol 26 ◽  
pp. 1460107
Author(s):  
C. ALBERTUS ◽  
E. HERNÁNDEZ ◽  
J. NIEVES
Keyword(s):  
Heavy Quark ◽  
Quark Mass ◽  
Semileptonic Decay ◽  
Spin Symmetry ◽  
Mass Limit ◽  
Electromagnetic Decays ◽  
Heavy Quark Mass ◽  
Quark Spin ◽  
Heavy Quark Spin Symmetry ◽  
Symmetry Relations

We show that semileptonic and electromagnetic decays involving spin-1/2 doubly heavy bc baryons are very sensitive to hyperfine mixing in their wave functions. We further show how heavy quark spin symmetry relations, obtained in the infinite heavy quark mass limit and near zero recoil, could be used to extract the admixtures in a model independent way from semileptonic decay data. On the other hand the infinite heavy quark mass limit gives wrong predictions in the electromagnetic case.

scholarly journals Enhanced breaking of heavy quark spin symmetry

2014 ◽  
Vol 738 ◽  
pp. 172-177 ◽  
Author(s):  
Feng-Kun Guo ◽  
Ulf-G. Meißner ◽  
Cheng-Ping Shen
Keyword(s):  
Heavy Quark ◽  
Spin Symmetry ◽  
Quark Spin ◽  
Heavy Quark Spin Symmetry

scholarly journals CHARMING BARYONS

2014 ◽  
Vol 26 ◽  
pp. 1460124
Author(s):  
C. GARCIA-RECIO ◽  
L. L. SALCEDO ◽  
D. GAMERMANN ◽  
J. NIEVES ◽  
O. ROMANETS ◽  
...  
Keyword(s):  
Heavy Quark ◽  
Spin Symmetry ◽  
Flavor Symmetry ◽  
Minimal Extension ◽  
Heavy Flavor ◽  
Vector Mesons ◽  
Quark Spin ◽  
Heavy Quark Spin Symmetry ◽  
Experimental Values

We study odd-parity baryonic resonances with one heavy and three light flavors, dynamically generated by meson-baryon interactions. Special attention is paid to Heavy Quark Spin Symmetry (HQSS), hence pseudoscalar and vector mesons and baryons with Jπ = 1/2+ and 3/2+ are considered as constituent hadrons. For the hidden-charm sector ([Formula: see text]), the meson-baryon Lagrangian with Heavy Flavor Symmetry is constructed by a minimal extension of the SU(3) Weinberg-Tomozawa (WT) Lagrangian to fulfill HQSS, such that not new parameters are needed. This interaction can be presented in different formal ways: as a Field Lagrangian, as Hadron creation-annihilation operators, as SU(6)×HQSS group projectors and as multichannel matrices. The multichannel Bethe-Salpeter equation is solved for odd-parity light baryons, hidden-charm N and Δ and Beauty Baryons (Λb). Results of calculations with this model are shown in comparison with other models and experimental values for baryonic resonances.

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