Analysis of recent CLAS data on f1(1285) photoproduction

Abstract

Based on the experimental data released recently by the CLAS Collaboration, the f 1 (1285) photoproduction off a proton target is investigated in an effective Lagrangian approach. In our model, s-channel, u-channel, and t-channel Born terms are included to calculate the differential cross sections, which are compared with the recent CLAS experiment. An interpolating Reggeized treatment is applied to the t channel, and it is found that the t-channel contribution is dominant in the f 1 (1285) photoproduction and the u-channel contribution is responsible for the enhancement at backward angles. The present calculation does not take into account any explicit s-channel nucleon-resonance contribution; nevertheless, our model provides a good description of the main features of the data. It suggests small couplings of the f 1 (1285) and the nucleon resonances in this energy region.

f1(1285) → e+e- decay and direct f1 production in e+e- collisions

“…A few theoretical models consistent with this result are proposed already [27][28][29]. The total f 1 width measured by CLAS Collaboration Γ CLAS f = (18.4 ± 1.4) MeV is also considerably smaller than the PDG value, Γ f = (24.1 ± 1.0) MeV.…”

“…There are some papers concerning f 1 → ρ 0 γ decay, where the amplitude M( f 1 → ρ 0 γ) is parametrized only by one constant [26,28,29]. These models correspond to our model at g 1 = 0.…”

Study on the reaction of γp→f1(1285)p in Regge-effective Lagrangian approach

“…The current information about this reaction is not enough to distinguish our model and the one of Ref. [22]. To shed light on the relevant mechanisms of the γp → f 1 (1285)p reaction, the further measurement of the total cross sections is called for.…”

“…It should be noted that after we submitted this work to arXiv, Wang and He also discussed the γp → f 1 (1285)p reaction within a similar way [22], where the t-channel ρ and ω trajectories exchanges, the s-and u-channel nucleon term are considered, and the s-channel nucleon resonances are not included. They suggested that the s-channel nucleon resonances is not very large.…”

Decay rates f1(1285)→ρ0π+Osipov1, Пивоваров2, Волков3 2018Phys. Rev. D7140View full textAdd to dashboardCite

“…This includes a recent measurement of the branching fraction of the τ → f 1 πν τ decay [27] and its theoretical description given in the different approaches [28][29][30][31][32]. In a number of works, the electromagnetic vertices f 1 ργ and f 1 ωγ have been considered [33][34][35]. The vertex f 1 γγ is important in the study of the hyperfine structure of muonic hydrogen [36].…”