Transverse Lambda Polarization at LHC
Transverse polarization of Lambda hyperons produced in p p and p Pb collisions is discussed. A factorized description in the intermediate to high p_T region is considered that involves transverse momentum and spin dependence in the fragmentation process. Consequences and suggestions for investigations at LHC are pointed out for the process p + p -> Lambda^uparrow + jets + X at midrapidity and p + p/Pb -> Lambda^uparrow + X in the forward region.
Hyperon polarization in inclusive hadronic production
A QCD formula for the polarization in the large-pT Λ hyperon production in the unpolarized nucleon-nucleon collision at large xF is derived. We focus on the mechanism in which the chiral-odd spin-independent twist-3 quark distribution EF(x,x) becomes the source of the transversely polarized quarks fragmenting into the polarized Λ. A simple model estimate for that contribution shows the possibility that it gives rise to a sizable Λ polarization.
AXIOMATISABILITY OF WEAKLY FLAT, FLAT, AND PROJECTIVE S-ACTS
ABSTRACT This paper gives necessary and sufficient conditions on a monoid S that the class of flat left S-acts be (first order) axiomatisable. It presents also a streamlined version of the result of Stepanova that the class of projective left S-acts is axiomatisable if and only if the strongly flat left S-acts are axiomatisable and S is left perfect.