Köln 2004 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 38: Electromagnetic and Hadronic Probes VI

HK 38.7: Vortrag

Donnerstag, 11. März 2004, 15:30–15:45, B

Coupled channels calculations for photo-induced K-Λ and K-Σ production — •Alexander Usov and Olaf Scholten — KVI, 9747 AA Groningen, The Netherlands

We calculated K-Λ and K-Σ photoproduction in gauge-invariant coupled channels framwork. Different recipe’s for restoring gauge invariance are compared, such as Ohta’s minimal-substitution method[1] and Davidson - Workman’s recipe[2]. The difference between these procedures is analyzed in terms of a four-point ’contact’-term. We find that the calculated cross sections strongly depend on the choice for this contact term. A recent microscopic calculation[3] suggest that the structure of the contact term depends strongly on the mass of the intermediate particles used to dress the vertex. A consistent calculation of vertex dressing, in line with [4] is thus called for.

[1] K. Ohta, Phys. Rev. C40, 1335 (1989); S. Kondratyuk and O. Scholten, Nucl. Phys. A677, 396 (2000)

[2] R.M. Davidson and R. Workman, Phys. Rev. C63, 025210 (2001); and Phys. Rev. C63, 058201 (2001)

[3] A.Yu. Korchin and O. Scholten, Phys. Rev. C68, 045206 (2003)

[4] S. Kondratyuk and O. Scholten, Phys. Rev. C64, 024005 (2001)