Dr Erin Seder (CEA Saclay DSM/IRFU/SPhN/LSN)
The latest measurements of charged pion, kaon, and unidentified hadron multiplicities in semi-inclusive deep-inelastic scattering from the COMPASS experiment at CERN are presented. The data were collected using a 160 GeV muon beam incident on an isoscalar 6LiD target. The large statistics collected cover a wide kinematic range in photon virtuality: 1 < Q2 < 50 (GeV/c)2, relative virtual-photon energy: 0.1 < y < 0.7 , Bjorken scaling variable: 0.004 < x < 0.4, and relative hadron energy: 0.2 < z < 0.85. In addition, we present the charge sum of the multiplicities integrated over z. The results of the pion and unidentified hadron sums are in very good agreement with LO expectations, while the results of the kaon sum show a different x dependence than that predicted using the current DSS ratio of fragmentation functions Dstr/Dfav.
Dr Fabienne Kunne (CEA Saclay DSM/IRFU/SPhN/LSN)