A measurement of $\Lambda$ polarization in inclusive production by $\Sigma^-$ of 340-GeV/c in C and Cu targets

The WA89 collaboration Adamovich, M.I. ; Alexandrov, Yu.A. ; Baranov, S.P. ; et al.
Eur.Phys.J.C 32 (2004) 221-228, 2004.
Inspire Record 645459 DOI 10.17182/hepdata.43190

We have measured the polarization of $\Lambda$ hyperons produced inclusively by a $\Sigma^-$ beam of 340 GeV/c momentum in nuclear targets. From a sample of 9.5 millions of identified $\Lambda$ decays, polarizations were determined in the range $x_F \gt 0.1$ and $p_t\leq 1.6$ GeV/c . The polarization w.r.t. the production normal is mainly positive for $x_F \geq 0.3$. At fixed values of $x_F$, it increases with $p_t$ to a maximum between $p_t = 0.5$ and $p_t = 1$ GeV/c , and then decreases to zero or even negative values, in sharp contrast to the plateau above $p_t = 1$ GeV/c observed in inclusive $\Lambda$ production by protons.

8 data tables

Measured values of the LAMBDA polarization as a function of PT in the XL range 0.1 to 0.2.

Measured values of the LAMBDA polarization as a function of PT in the XL range 0.2 to 0.3.

Measured values of the LAMBDA polarization as a function of PT in the XL range 0.3 to 0.4.

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Measurement of the polarization of Lambda0, anti-Lambda0, Sigma+ and Xi- produced in a Sigma- beam of 330-GeV/c

The WA89 collaboration Adamovich, M.I. ; Albertson, E. ; Alexandrov, Yu. A. ; et al.
Z.Phys.A 350 (1995) 379-386, 1995.
Inspire Record 375458 DOI 10.17182/hepdata.48194

The polarization of Lambda0, AntiLambda0, Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams.

3 data tables

Target Consisted of a copper and a carbon block arranged side by side.

Target Consisted of a copper and a carbon block arranged side by side.

Target Consisted of a copper and a carbon block arranged side by side.