Tau * 3 mu so far - University of Manchester

Report
•Analysis
using GaudiPython, python configurables and
LoKi in DaVinci
•Using
StdLooseMuons
•Hits
in M2 + M3 for 3 GeV < p < 6 GeV
•Hits in M2 + M3 + (M4 or M5) for 6 GeV < p < 10 GeV
•Hits in M2 + M3 + M4 + M5 for P > 10 GeV
•Decay
descriptors from ParticleTable.txt
•
Sources of τ in one year at full running conditions
LHCb acceptance ~ 5 x 1010 per year
•Assume BR ~ 2 x 10-8
~1000 events per year
•In
Background
b (10000000) – 1,010,045 events ~ 2pb-1
•Inclusive b Di μ (10012000) – 523, 217events
•Inclusive c (20000000) – 104,506 events ~ 30nb-1
•Inclusive Ds (23263001) – 107,431 events ~ 0.2pb-1
•Inclusive J/Ψ (24142000) – 123,545 events ~ 25pb-1
•Inclusive
Signal
•τ→
3 μ (31113001) – 30,000 events
Inital cuts (from Grant)
•μ
PID vs π > -5
•Min IP χ2 wrt PV > 3
•Track χ2/DoF < 4
•pt > 0.2 GeV
•τ
• Muons
• Tau
mass difference from PDG < 120 MeV
•Vertex χ2/DoF < 9
•Vertex IP χ2 < 5
•Cos of daughter momentum and direction of vertex >
0.999
Cuts from StrippingTriMuons
•3
muons with pt > 0.3 GeV
and Min IP χ2 wrt PV > 4
•1 muon with pt > 1 GeV
•τ
• Muons
• Tau
mass difference from PDG < 150 MeV
•Vertex χ2 < 25
•Pseudo-lifetime wrt primary vertex > 40µm
Current cuts
• Muons
• Tau
•3
muons with pt > 0.2 GeV
•τ
mass difference from PDG < 200 MeV
Background Datasets
Inc B DiMuon 258,339/523,217 = 49.4%
• Inc B 68,170/ 1,010,045 = 6.7%
• Inc C 4,900/104,506 = 4.7%
• Inc Ds 6,703/107,431 = 6.2%
• Inc J/Psi 10,585/123,545 = 8.6%
•
Signal Datasets
•Tau 2 3 Mu 25,460,/30,000 = 84.9%
Two approaches to analysis (from Grant)
1.
Standard Cuts
E.g. Tau mass, Muon PIDmu, DiMuon masses
2.
Geometrical likelihood
E.g. Angles, IP, pt, pt asymmetry

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