Charmed baryon [lambda][subscript]c+ decays with a [sigma]+ in the final state and decay asymmetry parameters
Author: Song Yang
Publisher:
Published: 1993
Total Pages: 0
ISBN-13:
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Author: Song Yang
Publisher:
Published: 1993
Total Pages: 0
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DOWNLOAD EBOOKAuthor: C.E.K. Charlesworth
Publisher:
Published: 1992
Total Pages: 0
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DOWNLOAD EBOOKThe charmed baryon $\Lambda\sbsp{c}{+}$ has been observed using the ARGUS detector in the DORIS II $e\sp{+}e\sp-$ storage ring at DESY. The ARGUS experiment is a 4$\pi$ magnetic solenoidal detector used to observe $e\sp{+}e\sp-$ annihilations at center-of-mass energies around 10.4 GeV. We have studied 5 decays modes of the $\Lambda\sbsp{c}{+}$. The decay mode $\Lambda\sbsp{c}{+}\to pK\sp-\pi\sp+$ was used to measure the $\Lambda\sbsp{c}{+}$ fragmentation properties. A value of 0.24 $\pm$ 0.04 was found for the Peterson et al. parameter $\epsilon$, and the $\sigma(\Lambda\sbsp{c}{+}$) $\cdot\ BR(\Lambda\sbsp{c}{+}\to pK\sp-\pi\sp+$) was measured to be 12.0 $\pm$ 1.1 $\pm$ 1.3) pb. The decay modes $\Lambda\sbsp{c}{+}\to\Lambda\pi\sp+$ and $\Lambda\sbsp{c}{+}\to\Sigma\sp0\pi\sp+$ were also studied. In the former the asymmetry parameter $\alpha\sb{\Lambda\sb{c}}$ was measured to be $-$1.0 $\pm$ 0.5, indicating that parity is maximally violated in this decay. The two production cross section times branching ratios were measured to be (2.2 $\pm$ 0.3 $\pm$ 0.3) pb and (2.0 $\pm$ 0.7 $\pm$ 0.3) pb respectively. Finally, a search was made for evidence of W-exchange in the decay $\Lambda\sbsp{c}{+}\to\Xi\sp-K\sp+\pi\sp+$. This final state can arise through a simple spectator decay or via the more exotic W-exchange decay into $\Xi\sp{*0}K\sp+$, where the $\Xi\sp{*0}$ subsequently decays into $\Xi\sp-\pi\sp+$. The two body rate was measured to be (35 $\pm$ 17)% of the three body rate, indicating that a significant portion of the $\Xi\sp-K\sp+\pi\sp+$ final state may occur via W-exchange.
Author:
Publisher:
Published: 1998
Total Pages:
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DOWNLOAD EBOOKThe strong decays of excited nonstrange baryons into the final states [Lambda]K, [Sigma]K, and for the first time into [Lambda](1405)K, [Lambda](1520)K, [Sigma](1385)K, [Lambda]K{sup *}, and [Sigma]K{sup *}, are examined in a relativized quark pair creation model. The wave functions and parameters of the model are fixed by previous calculations of N[pi] and N[pi][pi], etc., decays. The results show that it should be possible to discover several new negative parity excited baryons and confirm the discovery of several others by analyzing these final states in kaon production experiments. They also establish clear predictions for the relative strengths of certain states to decay to [Lambda](1405)K and [Lambda](1520)K, which can be tested to determine if a three-quark model of the [Lambda](1405)K is valid. The authors results compare favorably with the results of partial wave analyses of the limited existing data for the [Lambda]K and [Sigma]K channels. They do not find large [Sigma]K decay amplitudes for a substantial group of predicted and weakly established negative-parity states, in contrast to the only previous work to consider decays of these states into the strange final states [Lambda]K and [Sigma]K.
Author: Michael Manfred Zoeller
Publisher:
Published: 1994
Total Pages: 145
ISBN-13:
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