1 / 11

Significance of TAU observation in OPERA

Questions to OPERA: 1. Does it exist the n m – n t oscillation ? 2. Is it coherent with expectation ?. Significance of TAU observation in OPERA. We compute it as function of observed EVENTS (instead of the canonical dependence of LUMINOSITY). Scenarios .

star
Download Presentation

Significance of TAU observation in OPERA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Questions to OPERA: 1. Does it exist the nm – nt oscillation ? 2. Is it coherent with expectation ? Significance of TAU observation in OPERA We compute it as function of observed EVENTS (instead of the canonical dependence of LUMINOSITY) 22 September 2010

  2. Scenarios. • Standard: 5.3(2008+09) + 4.2(2010) + 4.2(2011) = 13.7*1019p.o.t • Smallcompensation in 2011: 5.3+4.2+4.5 = 14.0 • More in 2010&2011: 5.3+4.7+5.0 = 15.3 • Add MTE in 2011: 5.3+4.7+5.5 = 15.5 • Add 2013 with MTE: 5.3+4.7+5.5+5.0 = 20.5 22 September 2010

  3. SIGNAL: for each scenario the 95% C.L. on the corresponding Poisson pdf is computed: • lower and higher limits on the TAU events we may observed • corresponding significance is computed • (use Proposal efficiencies * 0.8, use 20% of error) BACKGROUND: use Proposal * 0.8 (we factorize out the different CC and NC efficiencies). Use 50% of error (not so relevant). This is a CONSERVATIVE choice (also because all channel are taken in a whole) And of course, we do not consider here the improvement in the background estimation with the increase of statistics 22 September 2010

  4. Check for 2008+2009 Data Sample: Ntau=0.8*10.4*5.3/22.5=1.96±0.39 Nbck=0.8*0.75*5.3/22.5=0.14±0.07 1 2 3 0 4 95% of C.L. 22 September 2010

  5. and the obtainable significance is quite fluctuating ! # s observation evidence indication # N (but, remember, only with largest bck) 22 September 2010

  6. # s limit of computation and use Feldman-Cousins Mean expect. Scen. 5 Scen. 1 # N Conclusions: if > 5-6 events we find “observation” anyway even with 20.5*1019 p.o.t we may not “observe” (but, remember, only with largest bck) 22 September 2010

  7. Similar to curves of Proposal • At present really missing deeper studies with better Analysis • and Monte Carlos • 3.My conclusion is however similar: Luminosity does not really matter • for the signal • 4.We have to point towards BACKGROUND This is valid while answering question no. 1…. 22 September 2010

  8. 2. “Coherence” of the OPERA oscillation measure # s “distant” from MINOS Need 2013-14 !! 5.3x1019 p.o.t 13.7x1019 p.o.t 15.5x1019 p.o.t 95% C.L. 20.5x1019 p.o.t 90% C.L. # of observed events FEW events: difficult but affordable (remember, Tau with 80% efficiency) Luca Stanco – ISTITUTO NAZIONALE di FISICA NUCLEARE - Padova 22 September 2010 6 Maggio 2010 8

  9. Conclusions: OPERA is dominated by statistics, but... the Physics Results can be extracted afterwords, only once the Full DATA Sample has been exploited 22 September 2010

  10. Backup 22 September 2010

  11. 13.7 15.5 14.0 20.5 15.3 22 September 2010

More Related