Analysis of recent CLAS data on Σ * (1385) photoproduction off a neutron target

et al. 2019

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The f 1 (1420) productions via pion and kaon induced reactions on a proton target are investigated in an effective Lagrangian approach. Two treatments of the t-channel Born term, the Feynman model and the Regge model, are introduced to calculate the total and differential cross sections of the π − p → f 1 (1420)n and K − p → f 1 (1420)Λ reactions. The numerical results indicate that the experimental data of the total cross section of the π − p → f 1 (1420)n reaction can be reproduced in both the Feynman and the Regge models. Based on the parameters determined in the pion induced reaction, the cross sections of the K − p → f 1 (1420)Λ reaction, about which there is little data found in the literature, are predicted in the same beam momentum range. It is found that the line shapes of the total cross section obtained in a kaon induced reaction with two treatments are quite different. The cross sections for both reactions are at an order of magnitude of µb, or larger, at a beam momenta up to 10 GeV/c. The differential cross sections for both pion and kaon induced reactions are also present. It is found that in the Regge model, the t channel provides a sharp increase at extreme forward angles. The results suggest that the experimental study of the f 1 (1420) in the kaon induced reaction on a proton target is as promising as in the pion induced reaction. Such an experimental measurement is also very helpful to clarify the production mechanism of the f 1 (1420).

Section: Numerical Resultsmentioning

confidence: 90%

Productions of f1(1420) in pion and kaon induced reactions

et al. 2019

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“…In Refs. [20,21], the local gauge invariance of the Regge trajectory was discussed. In the case of this work, the gauge invariance is kept because the Lagrangians for the t channel produce an amplitude which keeps gauge invariance by itself.…”

Section: B Interpolating Reggeized T Channelmentioning

confidence: 99%

Analysis of recent CLAS data on f1(1285) photoproduction

2017

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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.

“…[27,35]. For describing the P b production in photon and pion induced processes, the following Lagrangians are needed [22,23,[36][37][38], where N, A, P b , π, and ϒ are the nucleon, photon, P b state, pion, and ϒ meson fields, respectively. And τ is the Pauli matrix.…”

Section: A Lagrangians For the P B Productionmentioning

confidence: 99%

Systematic study of the production of hidden-bottom pentaquarks via γp and π−p scatterings

Chen

2020

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In this work, the production of hidden-bottom pentaquark P b states via γp and π − p scatterings is studied within an effective Lagrangian approach and the vector-meson-dominance mechanism. For the P b production in the process γp → ϒp, the dipole Pomeron model is employed to calculate the background contribution, and the experimental data can be well described. For the process π − p → ϒn, the Reggeized t-channel with π exchange is considered as the main background for the P b production. The cross section from the t-channel π exchange is very small due to weak coupling of P b state to the ππ channel predicted theoretically. Near the threshold, two-peak structure from the states P b ð11080Þ and P b ð11125Þ can be observed if energy bin width is chosen as 0.01 GeV, and the same result is obtained in the π − p scattering. Moreover, by taking the branching ratio of Br½P b → πN ≃ 0.05%, the numerical result shows that the average value of the cross section from the P b ð11080Þ state produced in the γp or π − p scattering reaches at least 0.1 nb with a bin of 0.1 GeV. Even if we reduce the branching ratio of the P b state into πN channel by one order, the theoretical average of the cross section from P b ð11080Þ production in π − p scattering can reach the order of 0.01 nb with a bin of 0.1 GeV, which means that the signal can still be clearly distinguished from the background. The experimental measurements and studies on the hidden-bottom pentaquark P b state production in the γp or π − p scattering near-threshold energy region around W ≃ 11 GeV are strongly suggested, which are accessible at COMPASS and JPARC. Particularly, the result of the photoproduction suggests that it is very promising to observe the hidden-bottom pentaquark at the proposed EicC facility in China.