EXOTIC BARYONS INSPIRE   JSON PDGID:
B172

${{\mathit P}_{{{c {{\overline{\mathit c}}}}}}{(4457)}^{+}}$

$I(J^P)$ = $1/2(?^{?})$ 

was ${{\mathit P}_{{{c}}}{(4450)}}$
A resonance seen in ${{\mathit \Lambda}_{{{b}}}^{0}}$ $\rightarrow$ ${{\mathit P}_{{{c}}}^{+}}{{\mathit K}^{-}}$, then ${{\mathit P}_{{{c}}}}$ $\rightarrow$ ${{\mathit J / \psi}}{{\mathit p}}$, with a significance of 12 standard deviations. The ${{\mathit J / \psi}}{{\mathit p}}$ quark content is ${{\mathit u}}{{\mathit u}}{{\mathit d}}{{\mathit c}}{{\overline{\mathit c}}}$, a pentaquark. See also the ${{\mathit P}_{{{c {{\overline{\mathit c}}}}}}{(4380)}^{+}}$. In the best amplitude fit, the two states have opposite parity, one having $\mathit J = 3/2$, the other $\mathit J = 5/2$. Extraction of the pentaquark signals requires some understanding of the dominant ${{\mathit K}^{-}}{{\mathit p}}$ background. AAIJ 2015P used a model-dependent approach. AAIJ 2016AG reanalyzed the data making minimal assumptions about the ${{\mathit K}^{-}}{{\mathit p}}$ background, and thus confirmed the strong significance of the pentaquark signals.
${{\mathit P}_{{{c {{\overline{\mathit c}}}}}}{(4457)}^{+}}$ MASS   $4457.3 {}^{+4.0}_{-1.8}$ MeV 
 
${{\mathit P}_{{{c {{\overline{\mathit c}}}}}}{(4457)}^{+}}$ WIDTH   $6.4 {}^{+6.0}_{-2.8}$ MeV 
 
$\Gamma_{1}$ ${{\mathit J / \psi}}{{\mathit p}}$   seen 828
 
FOOTNOTES