Amplitude analysis of the ${\chi }_{c1}\to \eta {\pi }^{+}{\pi }^{-}$ decays

Abstract

Using $448.0\times 10^6$~$\psi (3686)$ events collected with the BESIII detector, an amplitude analysis is performed for $\psi (3686)\to \gamma {\chi }_{c1}$, ${\chi }_{c1}\to \eta {\pi }^{+}{\pi }^{-}$ decays. The most dominant two-body structure observed is $a_0(980{)}^{\pm }{\pi }^{\mp }$; $a_0(980{)}^{\pm }\to \eta {\pi }^{\pm }$. The $a_0(980)$ line shape is modeled using a dispersion relation, and a significant non-zero $a_0(980)$ coupling to the ${\eta }^{\prime }\pi$ channel is measured. We observe ${\chi }_{c1}\to a_2(1700)\pi$ production for the first time, with a significance larger than 17$\sigma$. The production of mesons with exotic quantum numbers, $J^{PC}=1^{-+}$, is investigated, and upper limits for the branching fractions ${\chi }_{c1}\to {\pi }_1(1400{)}^{\pm }{\pi }^{\mp }$, ${\chi }_{c1}\to {\pi }_1(1600{)}^{\pm }{\pi }^{\mp }$, and ${\chi }_{c1}\to {\pi }_1(2015{)}^{\pm }{\pi }^{\mp }$, with subsequent ${\pi }_1(X{)}^{\pm }\to \eta {\pi }^{\pm }$ decay, are determined.

14 pages, 6 figures

References in corpus (6)

• Hybrid Mesons
• Re-analysis of data on a0(1450) and a0(980)
• Confirmation of a pi_1^0 Exotic Meson in the ηπ^0 System
• $f_0(500)$, $f_0(980)$ and $a_0(980)$ production in the ${\chi }_{c1}\to \eta {\pi }^{+}{\pi }^{-}$ reaction
• Predictions for ${\eta }_c\to \eta {\pi }^{+}{\pi }^{-}$ producing $f_0(500)$, $f_0(980)$ and $a_0(980)$
• Measurements of $\psip$ decays into $\gamma K\bar{K}\pi$ and $γη\pipi$

Cited by in corpus (28)

• 50 Years of Quantum Chromodynamics
• A Review on Partial-wave Dynamics with Chiral Effective Field Theory and Dispersion Relation
• Partial wave analysis of $J/\psi \to \gamma \eta {\eta }^{\prime }$
• Review of the low-lying excited baryons ${\Sigma }^{\ast }(1/2^{-})$
• Abnormal isospin violation and $a_0-f_0$ mixing in the $D_s^{+}\to {\pi }^{+}{\pi }^0{a}_0(980)(f_0(980))$ reactions
• Evidence of the low-lying baryon ${\Sigma }^{\ast }(1/2^{-})$ in the process ${\Lambda }_c^{+}\to \eta {\pi }^{+}\Lambda$
• Roles of $a_0(980)$, $\Lambda (1670)$, and $\Sigma (1385)$ in the ${\Lambda }_c^{+}\to \eta \Lambda {\pi }^{+}$ decay
• Hadronic three-body D decays mediated by scalar resonances
• $Z_{cs}$ states from the $D_s^{\ast }{\bar{D}}^{\ast }$ and $J/\psi K^{\ast }$ coupled channels: Signal in $B^{+}\to J/\psi \varphi K^{+}$ decay
• Constructing the $J^{P(C)}=1^{-(+)}$ light flavor hybrid nonet with the newly observed ${\eta }_1(1855)$
• Theoretical description of the $\mathbf{J}/\mathbf{\psi }\to \mathbf{\eta }({\mathbf{\eta }}^{\prime }){\mathbf{h}}_1(1380)$, $\mathbf{J}/\mathbf{\psi }\to \mathbf{\eta }({\mathbf{\eta }}^{\prime }){\mathbf{h}}_1(1170)$ and $\mathbf{J}/\mathbf{\psi }\to {\mathbf{\pi }}^0{\mathbf{b}}_1(1235{)}^0$ reactions
• Study of the Decay $D_s^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}\eta$ and Observation of the W-annihilation Decay $D_s^{+}\to a_0(980{)}^{+}{\rho }^0$
• Amplitude analysis and branching fraction measurement of $D_s^{+}\to K^{-}{K}^{+}{\pi }^{+}{\pi }^0$
• Observation of $D^{+}\to K_S^0{a}_0(980{)}^{+}$ in the amplitude analysis of $D^{+}\to K_S^0{\pi }^{+}\eta$
• Three-body unitary coupled-channel approach to radiative $J/\psi$ decays and $\eta (1405/1475)$
• Observation of ${\Lambda }_c^{+}\to \Lambda a_0(980{)}^{+}$ and Evidence for $\Sigma (1380{)}^{+}$ in ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}\eta$
• $a_0(980)-f_0(980)$ mixing in ${\chi }_{c1}\to {\pi }^0{f}_0(980)\to {\pi }^0{\pi }^{+}{\pi }^{-}$ and ${\chi }_{c1}\to {\pi }^0{a}_0(980)\to {\pi }^0{\pi }^0\eta$
• Amplitude analysis and branching-fraction measurement of $D_s^{+}\to K_S^0{K}^{-}{\pi }^{+}{\pi }^{+}$
• Semileptonic decays $D\to \eta \pi e^{+}{\nu }_e$ in the $a_0(980)$ region
• ${\chi }_{c1}$ decays into a pseudoscalar meson and a vector-vector molecule
• Study of $a_0^0(980)$-$f_0(980)$ mixing from $a_0(1450)\to a_0^0(980)f_0(500)\to {\pi }^{+}{\pi }^{-}{f}_0(500)$
• $J/\psi$ decay to $\varphi ,\omega ,K^{\ast 0}$ plus $f_0(1370)$, $f_0(1710)$, $K_0^{\ast }(1430)$, $f_2(1270)$, $f_2^{\prime }(1525)$ and $K_2^{\ast }(1430)$: role of the $D$-wave for tensor production
• Low-mass enhancement of kaon pairs in $B^{+}\to {\bar{D}}^{(\ast )0}{K}^{+}{\bar{K}}^0$ and $B^0\to D^{(\ast )-}{K}^{+}{\bar{K}}^0$ decays
• The role of meson interactions in the $D_s^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}\eta$ decay
• Study of $D_s^{+}\to f_0(980){\rho }^{+}$ and $\varphi {\pi }^{+}$ decays through $D_s^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}{\pi }^0$
• Search for the light hadron decay ${\chi }_{c1}(3872)\to {\pi }^{+}{\pi }^{-}\eta$
• Study of the light scalar $a_0(980)$ through the decay $D^0\to a_0(980{)}^{-}{e}^{+}{\nu }_e$ with $a_0(980{)}^{-}\to \eta {\pi }^{-}$
• The ${\bar{B}}_s^0\to J/\psi {\pi }^0\eta$ decay and the $a_0(980)-f_0(980)$ mixing