The "$a_1(1420)$" peak as the $\pi f_0(980)$ decay mode of the $a_1(1260)$

Abstract

We study the decay mode of the $a_1(1260)$ into a ${\pi }^{+}$ in p-wave and the $f_0(980)$ that decays into ${\pi }^{+}{\pi }^{-}$ in s-wave. The mechanisms proceeds via a triangular mechanism where the $a_1(1260)$ decays into $K^{\ast }\bar{K}$, the $K^{\ast }$ decays to an external ${\pi }^{+}$ and an internal $K$ that fuses with the $\bar{K}$ to produce the $f_0(980)$ resonance. The mechanism develops a singularity at a mass of the $a_1(1260)$ around 1420 MeV, producing a peak in the cross section of the $\pi p$ reaction, used to generate the mesonic final state, which provides a natural explanation of all the features observed in the COMPASS experiment, where a peak observed at this energy is tentatively associated to a new resonance called $a_1(1420)$. On the other hand, the triangular singularity studied here gives rise to a remarkable feature, where a peak is seen for a certain decay channel of a resonance at an energy about 200 MeV higher than its nominal mass.

References in corpus (6)

• Dynamically Generated Open and Hidden Charm Meson Systems
• A Discussion on Triangle Singularities in the ${\Lambda }_b\to J/\psi K^{-}p$ Reaction
• $B^0$ and $B_s^0$ decays into $J/\psi$ $f_0(980)$ and $J/\psi$ $f_0(500)$ and the nature of the scalar resonances
• On the nature of $a_1(1420)$
• $f_1(1285)$ decays into $a_0(980){\pi }^0$, $f_0(980){\pi }^0$ and isospin breaking
• Observation of the ${\Lambda }_b^0\to J/\psi p{\pi }^{-}$ decay

Cited by in corpus (31)

• PANDA Phase One
• Role of a triangle singularity in the $\gamma p\to K^{+}\Lambda (1405)$ reaction
• Novel approaches in Hadron Spectroscopy
• Triangle singularity in the $J/\psi \to K^{+}{K}^{-}{f}_0(980)(a_0(980))$ decays
• Revising the $f_1(1420)$ resonance
• Triangular singularity and a possible $\varphi p$ resonance in the ${\Lambda }_c^{+}\to {\pi }^0\varphi p$ decay
• Triangle Singularity as the Origin of the $a_1(1420)$
• Triangle singularity mechanism for the $pp\to {\pi }^{+}d$ fusion reaction
• Axial meson exchange and the $Z_c(3900)$ and $Z_{cs}(3985)$ resonances as heavy hadron molecules
• Abnormal isospin violation and $a_0-f_0$ mixing in the $D_s^{+}\to {\pi }^{+}{\pi }^0{a}_0(980)(f_0(980))$ reactions
• Triangle singularities in $B^{-}\to D^{\ast 0}{\pi }^{-}{\pi }^0\eta$ and $B^{-}\to D^{\ast 0}{\pi }^{-}{\pi }^{+}{\pi }^{-}$
• Triangle singularity in the $B^{-}\to K^{-}{\pi }^{0}X(3872)$ reaction and sensitivity to the $X(3872)$ mass
• Triangle singularity in $B^{-}\to K^{-}X(3872);X\to {\pi }^0{\pi }^{+}{\pi }^{-}$ and the X(3872) mass
• $f_2(1810)$ as a triangle singularity
• Tetraquarks in holographic QCD
• Test of the multiquark structure of $a_1(1420)$ in strong two-body decays
• Possibility of $T_{c\bar{s}}(2900)$ as the resonance-like structure induced by threshold effects
• Threshold effects as the origin of $Z_{cs}(4000)$, $Z_{cs}(4220)$ and $X(4700)$ observed in $B^{+}\to J/\psi \varphi K^{+}$
• Comprehensive study of light axial vector mesons with the presence of triangle singularity
• Photo- and electro-production of narrow exotic states: from light quarks to charm and up to bottom
• Role of the triangle mechanism in the ${\Lambda }_b\to {\Lambda }_c{\pi }^{-}{f}_0(980)$ reaction
• Observation of a structure in the M${}_{p\eta }$ invariant mass distribution near 1700 MeV/$c^2$ in the $\gamma \mathbf{p}\to \mathbf{p}{\pi }^0\eta$ reaction
• Heating triangle singularities in heavy ion collisions
• The vertex corrections due to the triangle singularity mechanism in the light axial vector meson couplings to $K^{\ast }\bar{K}+c.c.$
• Effects of Final State Interactions on Landau Singularities
• The $\pi f_0(500)$ decay of the $a_1(1260)$
• $\Lambda (1405)$ mediated triangle singularity in the $K^{-}d\to p{\Sigma }^{-}$ reaction
• The role of triangle singularity in the decay process $D^0\to {\pi }^{+}{\pi }^{-}{f}_0(980),f_0\to {\pi }^{+}{\pi }^{-}$
• Triangle mechanism in the decay process $B_0\to J/\psi K^0{f}_0(980)(a_0(980))$
• Spectroscopy of $a_1$ mesons from lattice QCD with the truncated overlap fermions
• Meson Spectroscopy at COMPASS