Study of $a_1(1260)$ in the $γp \to π^+π^+π^- n$ reaction

Abstract

We investigate the discovery potential of the a1(1260) photoproduction in the γp → a1(1260) + n and γp → π + π + π − n reactions via the π-exchange mechanism. For the γp → π + π + π − n reaction, we perform a calculation for the differential and total cross sections by including the contributions from the a1(1260) intermediate resonance decaying into ρπ then into π + π + π − . Besides, the nonresonance process is also considered. With a lower mass of a1(1260), we get a fairly good description of the experimental data for the invariant π + π + π − mass distributions. For the γp → a1(1260) + n reaction, with our model parameters, the total cross section is of the order of 10 µb at photon beam energy Eγ ∼ 2.5 GeV. It is expected that our model calculations could be tested by future experiments.

Theoretical description of the $\boldsymbol{J/ψ\to η(η') h_1(1380)}$, $\boldsymbol{J/ψ\to η(η') h_1(1170)}$ and $\boldsymbol{J/ψ\to π^0 b_1(1235)^0}$ reactions

“…The three pion decay of the a 1 (1260) is studied in Ref. [23], the strong decays of the b 1 (1235) in Ref. [12], and the decay of f 1 (1285) → ρ 0 π + π − has been investigated in Ref.…”

“…Other strong or electromagnetic reactions involving axial vector mesons include the γp → π + π + π − η reaction studied in Ref. [23], the π − p → a 1 (1260)p reaction studied in Ref. [33], the e + e − → f 1 (1285)γ(a 1 (1260)γ) reactions studied in Ref.…”