Wednesday, September 28, 2011

OPERA numbers

From the OPERA experiment that found faster-than-light neutrinos:

  1. Width of the proton extraction: 10,500 ns
  2. Protons per extraction: 2.4E13
  3. Extractions per cycle: 2
  4. Total neutrino events : 16,111
  5. Total Protons delivered: 9.34E19
  6. CNGS Beam Run 2010 (29 April - 22 Nov): Total 4.04E19 Protons on Target
    CNGS Beam Run 2009 (27 May - 23 Nov): Total 3.52E19 Protons on Target
    CNGS Beam Run 2008 (8 Jun- 3 Nov): Total 1.78E19 Protons on Target
  1. Slide 15/84 http://cdsweb.cern.ch/record/1384486/ 
  2. Slide 13/84 http://cdsweb.cern.ch/record/1384486/ 
  3. Slide 13/84 http://cdsweb.cern.ch/record/1384486/ 
  4. Slide 42/84 http://cdsweb.cern.ch/record/1384486/  
  5. http://proj-cngs.web.cern.ch/proj-cngs/
Deduced numbers:


1. Number of extractions: 3.89E6
2. Probability of neutrino event per extraction: 4.14E-3
3. Probability of neutrino event per proton: 1.724E-16
4. Summed up over all extractions, average protons/ns = 8.9E15
5. Summed up over all extractions, the average neutrinos detected/ns = 16111/10500 = 1.5

    Plot from OPERA:(http://arxiv.org/abs/1109.4897)
    Plots from OPERA
    Notice the y-axis is binned as Events/150ns.

    PS: recent comments on OPERA's work
    1. Jon Butterworth http://www.guardian.co.uk/science/life-and-physics/2011/sep/24/1
    2. John P. Costella http://johncostella.webs.com/neutrino-blunder.pdf -- confirms the intuition that the edges are what are important. By his eyeballs 919 neutrino events at the leading and trailing edge of the pulse give most of the statistical significance. (If the pulses were perfect square pulses, then only the leading and trailing edges can give timing information.)

    PS: I don't buy Costella's arithmetic, however.