HADRONIC FORM FACTORS IN THE γp→K<sup>+</sup>Λ PROCESS

Mart, T.; Sari, Agustina

doi:10.1142/s0217732313500545

Cited by 10 publications

(2 citation statements)

References 22 publications

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“…where Λ had is the cut-off parameter, q 2 is the squared of four-momentum of the off-shell intermediate particle with the corresponding mass m. Note that this form has been used in most analyses of the meson-nucleon scattering as well as meson photoproduction. Clearly, the use of other types of form factor is also possible in this case and the effect of different hadronic form factors on the isobar model could become an important issue in kaon photoproduction [13].…”

Section: Isobar Modelmentioning

confidence: 99%

Are Hyperon Resonances Required in the Elementary K +Λ Photoproduction?

Mart

Nurhadiansyah

2012

Few-Body Syst

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We have investigated the role of hyperon resonances in the kaon photoproduction process, γ p → K + Λ , by using a covariant isobar model. To this end, new experimental data are used in the fitting process, whereas the old SAPHIR 1998 data are also used for comparison. The result indicates that the Λ (1600)P 01 and Λ (1810)P 01 hyperon resonances can significantly reduce the χ 2 and, simultaneously, can increase the hadronic form factor cut-off in the background terms. This finding is different from the result of the previous studies, which showed that the Λ (1800)S 01 was important for this purpose, instead of the Λ (1600)P 01 . IntroductionRecently, it has been shown that kaon photoproduction process provides an important tool for investigating missing resonances, the resonances predicted by constituent quark models but not observed yet by the Particle Data Group (PDG) [1]. The relatively small decay widths to pion-nucleon channel are believed to be the reason behind this fact. However, certain constituent quark models [2,3] predict that these resonances have larger decay widths to other channels, such as kaon-hyperon ones. Thus, kaon photoproduction is well suited to shed more light on the existence of these missing resonances.Whereas nucleon resonances have been intensively investigated by using kaon photoproduction, there has been no thorough study on hyperon resonances by means of this process. Ideally, such a study should be performed by using the kaon-nucleon scattering, in which hyperon resonances propagate in the s-channel. Furthermore, kaon-nucleon scattering experiment has become the main focus of recent experimental activities at JPARC in Japan [4]. Nevertheless, in order to achieve an accuracy similar to that obtained in experiments using electromagnetic beams performed at Jefferson Lab, MAMI, and Spring8, one needs very intense kaon beam. Moreover, it is widely understood that hadronic interaction is not as "clean" as the electromagnetic one. In view of this, kaon photoproduction could offer a complementary solution, since the hyperon resonance propagates in the u-channel and, therefore, the process is sensitive to certain observables at backward kaon scattering angles.More than a decade ago it was found that the second peak in the cross section of SAPHIR data [5] can be nicely reproduced by including a missing D 13 (1895) nucleon resonance in a covariant isobar model. [6]. An isobar model which includes this resonance and hadronic form factors was fitted to the SAPHIR data. The form factor cut-off Λ was allowed to vary during the fitting process and it was found that Λ = 0.64 GeV. Although there is no tool to measure this form factor directly, since it is an off-shell form factor, such a small cut-off was considered to be unreasonably soft [7] and the form factors were considered as an artificial ⋆ Dedicated to Professor Henryk Witala at the occasion of his 60th birthday.

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Section: Isobar Modelmentioning

confidence: 99%

Are Hyperon Resonances Required in the Elementary K +Λ Photoproduction?

Mart

Nurhadiansyah

2012

Few-Body Syst

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“…For example, at a total center of momentum (c.m.) energy W just above 2 GeV the necessity to include hadronic form factors [2][3][4] and the phenomenon of Regge behavior seems to be inexorable [5][6][7][8]. Clearly, such problems can be efficiently avoided by lowering the considered energy.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic production ofKΣon the nucleon near threshold

Mart

2014

Phys. Rev. C

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Photo-and electroproduction of KΣ have been investigated near their production thresholds by using an effective Lagrangian approach. For this purpose, the background amplitude is constructed from suitable Feynman diagrams, whereas the resonance terms are calculated by means of the Breit-Wigner form of multipoles. Experimental data available in the proton channels (K + Σ 0 and K 0 Σ + ) with energies up to 50 MeV above the thresholds have been utilized to extract the unknown parameters. In these proton channels the calculated observables fit nicely the experimental data, whereas in the neutron channels (K + Σ − and K 0 Σ 0 ) the predicted observables contain some uncertainties due to the the uncertainties in the values of helicity photon couplings. To this end, new K 0 Σ + photoproduction data are urgently required. The present analysis indicates the validity of the PΛ = − 1 3 PΣ relation derived a long time ago. In the electroproduction sector the present analysis confirms the smooth transition between photoproduction and low Q 2 electroproduction data. The effect of new Crystall Ball data is shown to be mild at the backward angles. It is also found that the electroproductions of K 0 Σ + and K 0 Σ 0 are practically not the suitable reactions for investigating the K 0 charge form factor, since the effect is small.

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