Measurements of $${\Xi }{^-} $$ and $$\overline{\Xi }{^+} $$ production in proton–proton interactions at $$\sqrt{s_{NN}}$$ = 17.3 $$\hbox {Ge}\hbox {V}$$ in the NA61/SHINE experiment

The production of $$\Xi (1321)^{-}$$ Ξ ( 1321 ) - and $$\overline{\Xi }(1321)^{+}$$ Ξ ¯ ( 1321 ) + hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 $$\hbox {Ge}\hbox {V}\!/\!c$$ Ge / c . Double differential distributions in rapidity $${y}$$ y and transverse momentum $$p_{T}$$ p T are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both $${\Xi }{^-} $$ Ξ - and $$\overline{\Xi }{^+} $$ Ξ ¯ + . The rapidity and transverse momentum spectra are compared to transport model predictions. The $${\Xi }{^-} $$ Ξ - mean multiplicity in inelastic p+p interactions at 158 $$\hbox {Ge}\hbox {V}\!/\!c$$ Ge / c is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair.

Preliminary results on prompt \(\Xi^+/\Xi^-\) production ratio in pp collisions at\(\sqrt{s} = 7\) TeV

The ratio of prompt \(\Xi^+/\Xi^-\) production has been investigated from a limitedsample of data registered by the LHCb experiment at the CERN Large Hadron Colliderin 2010. This ratio has been determined in the rapidity region \(1.9 \leq y \leq 4.9\) covered bythe LHCb detector. The determination of anti-hyperons to hyperons production ratio willallow to study the transport of baryon number from pp collisions to final state hadrons andto constrain and tune Monte Carlo models.

An Artifact in Isolated Organ Perfusion Studies of Coagulation Factors

Using isolated rat livers, Mattii et al. (Proc. Soc. Exper. Biol. Med. 116, 69, 1964) and Olson et al. (J. Clin. Invest 45, 690, 1966) observed generation of modest amounts of factor V. With rabbit liver-spleen combinations, Dodds and Hoyer (Br. J. Haem. 26, 497, 1974) found factor VIII emerging. We have perfused rat livers with rat blood cells in bovine albumin-Tyrode’s solution. One-stage assays for factors V, VIII, XI and XII indicated release of all 4 clotting activities within the first hour of perfusion, followed by a slow diminution. However, the same occurred if there were no liver in the perfusion system. When the rath erythrocytes were free of platelets (> 90%) and leukocytes (> 75%) before mixing with albumin-Tyrode’s, the isolated liver generated factor XII but not factors V, VIII and XI. Production of fibrinogen, prothrombin and factors VII, IX and X was not altered by removing the leukocytes and platelets.