ΤAU→ 3 MU SO FAR•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

ΤAU SOURCES• Sources of τ in one year at full running conditions

•In LHCb acceptance ~ 5 x 1010 per year•Assume BR ~ 2 x 10-8

~1000 events per year

DATASETSBackground

•Inclusive 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

Signal

•τ→ 3 μ (31113001) – 30,000 events

CUTSInital cuts (from Grant)

•μ PID vs π > -5•Min IP χ2 wrt PV > 3•Track χ2/DoF < 4•pt > 0.2 GeV

•τ mass difference from PDG < 120 MeV•Vertex χ2/DoF < 9•Vertex IP χ2 < 5•Cos of daughter momentum and direction of vertex > 0.999

• Muons• Tau

CUTSCuts from StrippingTriMuons

•3 muons with pt > 0.3 GeV and Min IP χ2 wrt PV > 4•1 muon with pt > 1 GeV

•τ mass difference from PDG < 150 MeV•Vertex χ2 < 25•Pseudo-lifetime wrt primary vertex > 40µm

• Muons• Tau

CUTSCurrent cuts

•3 muons with pt > 0.2 GeV

•τ mass difference from PDG < 200 MeV

• Muons• Tau

RESULTSBackground 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%

RESULTSTwo 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

TMVA RESULTS

TMVA RESULTS

TMVA RESULTS