Τ au→ 3 mu so far

1. 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

2. 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

3. Datasets Background 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

4. Cuts • Muons • Tau Inital cuts (from Grant) μ PID vsπ > -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

5. Cuts • Muons • Tau Cuts 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

6. Cuts • Muons • Tau Current cuts 3 muons with pt >0.2 GeV τ mass difference from PDG < 200 MeV

7. Results 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%

8. Results Two approaches to analysis (from Grant) Standard Cuts E.g. Tau mass, MuonPIDmu, DiMuon masses Geometrical likelihood E.g. Angles, IP, pt, pt asymmetry

9. TMVA Results

10. TMVA Results

11. TMVA Results