A determination of the spin and parity of the Λð1405Þ is presented using photoproduction data from the CLAS detector at Jefferson Lab. The reaction γ þ p → Kþ þ Λð1405Þ is analyzed in the decay channel Λð1405Þ → Σþ þ π−, where the decay distribution to Σþπ− and the variation of the Σþ polarization with respect to the Λð1405Þ polarization direction determines the parity. The Λð1405Þ is produced, in the energy range 2.55 < W < 2.85 GeV and for 0.6 < cos θc:m: Kþ < 0.9, with polarization P ¼ 0.45 0.02ðstatÞ 0.07ðsystÞ. The analysis shows that the decays are in S wave, with the Σþ polarized such that the Λð1405Þ has spin-parity JP ¼ 1 2 −, as expected by most theories.
Spin and parity measurement of the Lambda(1405) baryon
CONTALBRIGO, Marco;LENISA, Paolo;PAPPALARDO, Luciano Libero;
2014
Abstract
A determination of the spin and parity of the Λð1405Þ is presented using photoproduction data from the CLAS detector at Jefferson Lab. The reaction γ þ p → Kþ þ Λð1405Þ is analyzed in the decay channel Λð1405Þ → Σþ þ π−, where the decay distribution to Σþπ− and the variation of the Σþ polarization with respect to the Λð1405Þ polarization direction determines the parity. The Λð1405Þ is produced, in the energy range 2.55 < W < 2.85 GeV and for 0.6 < cos θc:m: Kþ < 0.9, with polarization P ¼ 0.45 0.02ðstatÞ 0.07ðsystÞ. The analysis shows that the decays are in S wave, with the Σþ polarized such that the Λð1405Þ has spin-parity JP ¼ 1 2 −, as expected by most theories.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
