Test of the multiquark structure of $a_1(1420)$ in strong two-body decays

Abstract

We present an analysis of strong two-body decays of the $a_1(1420)$ with $J^{PC}=1^{++}$ recently reported by the COMPASS Collaboration at CERN. Following the interpretation of the COMPASS Collaboration that the $a_1$ is an unusual state with a four-quark $q\bar{q}s\bar{s}$ structure we consider two possible configurations for this state --- hadronic molecular and color diquark-antidiquark structures. We find that the dominant decay mode of the $a_1$ is the decay into $K$ and $K^{\ast }$. In particular, we calculate that the four decay modes $a_1\to VP$ with $VP=K^{\ast \pm }{K}^{\mp }$, $K^{\ast 0}{\bar{K}}^0$, ${\bar{K}}^{\ast 0}{K}^0$ together give a dominant contribution to the measured total width of about 150 MeV. The observational mode $a_1\to f_0(980)+{\pi }^0$ is significantly suppressed by one order of magnitude.

10 pages

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• On the nature of $a_1(1420)$
• The "$a_1(1420)$" peak as the $\pi f_0(980)$ decay mode of the $a_1(1260)$
• Four-quark structure of Zc(3900), Z(4430) and Xb(5568) states
• Form factors of the B-S-transitions in the covariant quark model
• $Z_b(10610)$ and $Z_b^{\prime }(10650)$ decays in a covariant quark model
• $a_1(1420)$ resonance as a tetraquark state and its isospin partner
• Tetraquarks in holographic QCD
• Peak locations and relative phase of different decay modes of the $a_1$ axial vector resonance in diffractive production
• Isospin-violating strong decays of scalar single-heavy tetraquarks

Cited by in corpus (6)

• Triangle Singularity as the Origin of the $a_1(1420)$
• Radiative decays $D^*_{(s)}\to D_{(s)}γ$ in covariant confined quark model
• Role of the triangle mechanism in the ${\Lambda }_b\to {\Lambda }_c{\pi }^{-}{f}_0(980)$ reaction
• Probing the ATOMKI X17 vector boson using Dalitz decays $V\to P{e}^{+}{e}^{-}$
• Spectroscopy of $a_1$ mesons from lattice QCD with the truncated overlap fermions
• Radiative transitions of charmonium states in the covariant confined quark model