Nuclear Theory·nucl-th

Thursday·March 30, 2017

5 papers—2 primary·3 cross-listed

03
Possible $D^{(*)} D ˉ^{(*)}$ and $B^{(*)} B ˉ^{(*)}$ molecular states in the extended constituent quark models
You-Chang Yang🇨🇳 · Zhi-Yun Tan🇨🇳 · Jialun Ping🇨🇳 · Hong-Shi Zong🇨🇳
The possible neutral $D^{(*)} D ˉ^{(*)}$ and $B^{(*)} B ˉ^{(*)}$ molecular states are studied in the framework of the constituent quark models, which is extended by including the $s$ -channel one gluon exchange. Using different types of quark-quark potentials, we solve the four-body Schrödinger equation by means of the Gaussian expansion method. The bound states of $D^{(*)} D ˉ^{(*)}$ with $J^{P C} = 1^{++}, 2^{++}$ and $B^{(*)} B ˉ^{(*)}$ with $J^{P C} = 0^{++}, 1^{+-}, 1^{++}, 2^{++}$ are obtained. The molecular states $D^{*} D ˉ$ with $J^{P C} = 1^{++}$ and $B^{*} B ˉ$ with $J^{P C} = 1^{+-}$ are good candidates for the $X (3872)$ and $Z_{b}^{0} (10610)$ , respectively.
↳ hep-phnucl-thEPJC(2017)·16 citations
04
Absorptive corrections for vector mesons. Matching to complex mass scheme and longitudinal corrections
L. A. Jiménez Pérez🇲🇽 · G. Toledo Sánchez🇲🇽
Unstable spin-1 particles are properly described by including absorptive corrections to the electromagnetic vertex and propagator, without breaking the electromagnetic gauge invariance. We show that the modified propagator can be set into a complex mass form, provided the mass and the width parameters, which are properly defined at the pole position, are replaced by energy dependent functions fulfilling the same requirements at the pole. We exemplify the case for the $K^{*} (892)$ vector meson, where the mass function deviates around 2 MeV from the $K π$ threshold to the pole position. The absorptive correction depends on the mass of the particles in the loop. For vector mesons, whose main decay is into two pseudoscalar mesons ( $P P^{'}$ ), the flavor symmetry breaking induces a correction to the longitudinal part of the propagator. Considering the $τ^{-} \to K_{S} π^{-} ν_{τ}$ decay, we illustrate these corrections by obtaining the modified vector and scalar form factors. The $K_{S} π^{-}$ spectrum is described considering the $K^{*} (892)$ and $K^{^{'} *} (1410)$ vectors and one scalar particle. Nonetheless, for this case, the correction to the scalar form factor is found to be negligible.
↳ hep-phnucl-thJ.Phys.G(2017)·8 citations
05
Triangle mechanisms in the build up and decay of the $N^{*} (1875)$
Daris Samart🇹🇭 · Wei-hong Liang🇨🇳 · Eulogio Oset🇪🇸
We have studied the $N^{*} (1875) (3/ 2^{-})$ resonance with a multichannel unitary scheme, considering the $Δ π$ and $Σ^{*} K$ , with their interaction extracted from chiral Lagrangians, and then have added two more channels, the $N^{*} (1535) π$ and $N σ$ , which proceed via triangle diagrams involving the $Σ^{*} K$ and $Δ π$ respectively in the intermediate states. The triangle diagram in the $N^{*} (1535) π$ case develops a singularity at the same energy as the resonance mass. We determine the couplings of the resonance to the different channels and the partial decay widths. We find a very large decay width to $Σ^{*} K$ , and also see that, due to interference with other terms, the $N σ$ channel has an important role in the $π π$ mass distributions at low invariant masses, leading to an apparently large $N σ$ decay width. A discussion is done, justifying the convenience of an experimental reanalysis of this resonance to the light of the findings of the paper, using multichannel unitary schemes.
↳ hep-phnucl-thPRC(2017)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE

Possible D(∗)Dˉ(∗) and B(∗)Bˉ(∗) molecular states in the extended constituent quark models

Absorptive corrections for vector mesons. Matching to complex mass scheme and longitudinal corrections

Triangle mechanisms in the build up and decay of the N∗(1875)

Affiliations

Possible $D^{()} D ˉ^{()}$ and $B^{()} B ˉ^{()}$ molecular states in the extended constituent quark models

Triangle mechanisms in the build up and decay of the $N^{*} (1875)$