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

Nbkg(M) = R(M) ×

• Ndir

LSpp(M) × Ndir LSmm(M)

(1) R(M) = Nmix

OS (M)

• Nmix

LSpp(M) × Nmix LSmm(M)

(2) 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

]

2

[GeV/c

µ µ

M 2 4 6 8 0.5 1 1.5 2

no pool

• ver R

pool integrated

ratio R ]

2

[GeV/c

µ µ

M 2 4 6 8 0.5 1 1.5 2

Ratio OS mix over OS dir 3/6 Teyssier dimuons analysis

Background subtraction

centrality pool

]

2

[GeV/c

µ µ

M 2 4 6 8 0.5 1 1.5 2

no pool

• ver R

pool integrated

ratio R

Entries 550086 Mean 2.55 RMS 2.183

]

2

[GeV/c

µ µ

M 2 4 6 8 0.5 1 1.5 2

Entries 550086 Mean 2.55 RMS 2.183

Ratio OS mix over OS dir 4/6 Teyssier dimuons analysis

Background subtraction

centrality pool

centrality range: 0.0 - 5.0 5.0 - 10.0 10.0 - 20.0 20.0 - 40.0 40.0 - 60.0 60.0 - 90.0

]

2

[GeV/c

µ µ

M 2 4 6 8 2 4 6

mix

R

5/6 Teyssier dimuons analysis

Outlook

/ ndf

2

χ 31437.8 / 388 EtaDalitz 424.9 ± 73228.2 Omega2Body 321.5 ± 15803.9 Phi2Body 442.2 ± 16380 OpenCharm 1339.8 ± 197857

]

2

[GeV/c

µ µ

M 0.5 1 1.5 2 2.5 3 3.5 ]

2

dN/dM [dimuons per 25 MeV/c 5 10 15

3

10 ×

/ ndf

2

χ 31437.8 / 388 EtaDalitz 424.9 ± 73228.2 Omega2Body 321.5 ± 15803.9 Phi2Body 442.2 ± 16380 OpenCharm 1339.8 ± 197857 / ndf

2

χ 31437.8 / 388 EtaDalitz 424.9 ± 73228.2 Omega2Body 321.5 ± 15803.9 Phi2Body 442.2 ± 16380 OpenCharm 1339.8 ± 197857

6/6 Teyssier dimuons analysis