References - Bogoliubov Laboratory of Theoretical Physics - JINR

The sensitivity of the data to the nucleon parton distribution functions is illustrated by
comparison of the results obtained using the parametrizations CTEQ5L [8] (solid line) and
GRV98LO [9] (dashed line). The GRV98 parton distributions have been chosen, because
the strange sea there is purely perturbative, originating only from the production of q¯qpairs
by gluons. On the contrary CTEQ allows explicit non-perturbative strangeness in
the nucleon. The amount of strangeness was extracted from dimuon experiments CCFR
and NuTeV [10]. This leads to ¯s(x) being nearly two times larger in CTEQ than in GRV98
for COMPASS energies in the x =0.001 − 0.01 range. Therefore the calculation of DLL
for ¯ Λ using CTEQ gives twice bigger spin transfer and is closer to the experimental points
in comparison with GRV98.
It should be noted that the polarization of Λ and ¯ Λ could be used as a tool to estimate
s(x) and¯s(x) independently of each other. More detailed description of the analysis could
be found in [12].
References
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[2] NOMAD Collaboration, P. Astier et al., Nucl. Phys., B588 (2000) 3.
[3] NOMAD Collaboration, P. Astier et al., Nucl. Phys., B605 (2001) 3.
[4] E665 Collaboration, M.R. Adams et al., Eur. Phys. J. C17 (2000) 263.
[5] HERMES Collaboration, A. Airapetian et al., Phys. Rev., D74 (2006) 072004.
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283.
[8] F. Olness et al., Eur. Phys. J., C40(2005) 145.
[9] M. Glück,E.Reya,A.Vogt,Eur.Phys.J.,C5 (1998) 461.
[10] CCFR and NuTeV Collaborations, M. Goncharov et al., Phys. Rev., D64 (2001)
112006.
[11] M. Burkardt, R.L. Jaffe, Phys. Rev. Lett., 70 (1993) 2537.
[12] COMPASS Collaboration, M. Alekseev et al., Eur. Phys. J. C64 (2009) 171.
322