Gerasimov-Drell-Hearn sum rule and the discrepancy between the new CLAS and SAPHIR data

Abstract

Contribution of the K + Λ channel to the Gerasimov-Drell-Hearn (GDH) sum rule has been calculated by using the models that fit the recent SAPHIR or CLAS differential cross section data. It is shown that the two data sets yield quite different contributions. Contribution of this channel to the forward spin polarizability of the proton has been also calculated. It is also shown that the inclusion of the recent CLAS C x and C z data in the fitting data base does not significantly change the result of the present calculation. Results of the fit, however, reveal the role of the S 11 (1650), P 11 (1710), P 13 (1720), and P 13 (1900) resonances for the description of the C x and C z data. A brief discussion on the importance of these resonances is given. Measurements of the polarized total cross section σ TT ′ by the CLAS, LEPS, and MAMI collaborations are expected to verify this finding.

Kaon Photoproduction on the Nucleon With Constrained Parameters

“…Near the production threshold the two well established resonances S 11 (1650) and P 13 (1720) show important roles in both fits. This finding emphasizes the results of our previous studies 5, 10 . Reference 11 has also arrived at the same result, except for the P 13 (1720).…”

Progress and Issues in the Electromagnetic Production of Kaon on the Nucleon

“…In Ref. 34 it is reported that the inclusion of these data reduces the complicated structure of the total cross sections σ TT ′ as shown in the right panel of Fig. 3, which indicates that the C x and C z data select only certain important resonances, i.e.…”

“…In view of this, Ref. 34 proposed to use other quantities which can be predicted by the models and can be directly compared with the results from other measurements or model predictions. One of the possible quantities is the contribution of the γp → K + Λ channel to the Gerasimov-Drell-Hearn (GDH) sum rule, 35 which relates the anomalous magnetic moment of the proton κ p to the total photoabsorption cross sections σ TT ′ , i.e.…”

“…It is then concluded that contribution from the model that fits to the SAPHIR data sets is more preferred . 34 Nevertheless, a see Section 3 for the definition of old data experimental measurement of the σ TT ′ is clearly required to confirm this claim. Since the SAPHIR detector has been dismantled, measurements of the σ TT ′ by the CLAS or MAMI collaboration seem to be the only choice.…”

Electromagnetic Productions of the Hyperon and the Hypertriton Using Real and Virtual Photons

“…In Ref. [10] it is suggested that measurements of the polarized total cross section σ TT ′ by the CLAS, LEPS, and MAMI collaborations are expected to help to solve this problem.…”