low mass dimuon production in p-Pb: preliminary investigations - PowerPoint PPT Presentation

low mass dimuon production in p-Pb: preliminary investigations Boris Teyssier ALICE Lyon April 15, 2015 Teyssier dimuons analysis

Datas analysis Datas period: LHC12d,e and f Triggers selection Data: MUL and MLL Mixing: MLL Centrality estimator: V0M 1/6 Teyssier dimuons analysis

Background subtraction � N dir LSpp ( M ) × N dir N bkg ( M ) = R ( M ) × LSmm ( M ) (1) N mix OS ( M ) R ( M ) = (2) � N mix LSpp ( M ) × N mix LSmm ( M ) Strategy for mixing events Mixed events having same conditions → created various pools (in this case z -vertex and centrality) Check if good pool 2/6 Teyssier dimuons analysis

Background subtraction z -vertex pool ratio R over R Ratio OS mix over OS dir pool integrated no pool 2 2 1.5 1.5 1 1 0.5 0.5 0 0 0 2 4 6 8 0 2 4 6 8 2 2 M [GeV/c ] M [GeV/c ] µ µ µ µ 3/6 Teyssier dimuons analysis

Background subtraction centrality pool ratio R over R Ratio OS mix over OS dir pool integrated no pool 2 2 Entries 550086 Entries 550086 Mean Mean 2.55 2.55 RMS RMS 2.183 2.183 1.5 1.5 1 1 0.5 0.5 0 0 0 2 4 6 8 0 2 4 6 8 2 2 M [GeV/c ] M [GeV/c ] µ µ µ µ 4/6 Teyssier dimuons analysis

Background subtraction centrality pool R mix centrality range: 6 0.0 - 5.0 5.0 - 10.0 4 10.0 - 20.0 20.0 - 40.0 2 40.0 - 60.0 60.0 - 90.0 0 0 2 4 6 8 2 M [GeV/c ] µ µ 5/6 Teyssier dimuons analysis

Outlook × 3 10 χ χ χ 2 2 2 ] / ndf / ndf / ndf 31437.8 / 388 31437.8 / 388 31437.8 / 388 2 dN/dM [dimuons per 25 MeV/c ± ± ± EtaDalitz EtaDalitz EtaDalitz 73228.2 73228.2 73228.2 424.9 424.9 424.9 ± ± ± Omega2Body Omega2Body Omega2Body 15803.9 15803.9 15803.9 321.5 321.5 321.5 ± ± ± Phi2Body Phi2Body Phi2Body 16380 16380 16380 442.2 442.2 442.2 15 ± ± ± OpenCharm OpenCharm OpenCharm 197857 197857 197857 1339.8 1339.8 1339.8 10 5 0 0 0.5 1 1.5 2 2.5 3 3.5 2 M [GeV/c ] µ µ 6/6 Teyssier dimuons analysis