Measurement of V-0 production ratios in pp collisions at root s=0.9 and 7 TeV

The (Lambda) over bar/Lambda and (Lambda) over bar /K-S(0) production ratios are measured by the LHCb detector from 0.3 nb(-1) of pp collisions delivered by the LHC at root s = 0.9TeV and 1.8 nb-1 at root s = 7TeV. Both ratios are presented as a function of transverse momentum, p(T), and rapidity, y, in the ranges 0.15 < p(T) < 2.50GeV/c and 2.0 < y < 4.5. Results at the two energies are in good agreement as a function of rapidity loss, Delta y = y(beam) - y, and are consistent with previous measurements. The ratio (Lambda) over bar/Lambda, measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio (Lambda) over bar /K-S(0), measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected. RI Galli, Domenico/A-1606-2012; Popovici, Bogdan/B-6521-2012; Muresan, Raluca-Anca/C-3725-2011; Patrignani, Claudia/C-5223-2009; Coca, Cornelia/B-6015-2012; Eklund, Lars/C-7709-2012; Soler, Paul/E-8464-2011; Leflat, Alexander/D-7284-2012; Petrolini, Alessandro/H-3782-2011; Sarti, Alessio/I-2833-2012