1 / 10

UW classification: background rejection

UW classification: background rejection. (An update – more details at future meetings). Review, tree status. Training samples 5M allgamma from v7r0p2 (SLAC farm) DC2 background: 4% of a day from v7r0p2 (UW farm)

avidan
Download Presentation

UW classification: background rejection

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. UW classification:background rejection (An update – more details at future meetings) T. Burnett

  2. Review, tree status • Training samples • 5M allgamma from v7r0p2 (SLAC farm) • DC2 background: 4% of a day from v7r0p2 (UW farm) • Packages classifier and GlastClassify : perform the training, save the resulting decision trees as data in GlastClassify • Current GR v7r1 tag has all the above trees. • Package merit : applies above trees to other tuple variables to define the CT tuple variables: CTgoodCal, CTvertex, CTgoodPsf, CTgamma T. Burnett

  3. Bill’s DC1 Background Analysis • Issues: • What is the residual rate? Can one satisfy the SR signal/noise of 105:1 and the Aeff requirement of 0.8 m2 ? • How does it compare with the extragalactic diffuse rate? • Can we identify characteristics of the remaining events allowing better rejection? • The background rate is now X2 more than for DC1. T. Burnett

  4. My requirement:Be able to measure the spectrum of the extragalactic diffuse to from 30 Mev to >100 Gev. Science issues: • is there an excess above 1 GeV that can only be explained by WIMP annihilation? • To what energy are we really sensitive? When does background overwhelm the extragalactic diffuse? • Note: I use the EGRET measurement as a reference: it is surely an overestimate. • We need to understand the background energy distribution! The following is based on 0.01 day DC2 background generated by v7r1 at UW, and the Extragalactic_diffuse source T. Burnett

  5. Current, very preliminary status CTgamma cut 0.9 0.96 0.99 T. Burnett

  6. Current estimate: current background dominates above ~10 GeV So what are the characteristics of those events? Bill noticed this clue: one suggestion was that the MIP finding might help separate the residual background. T. Burnett

  7. I confirm Bill’s observation Clearly see downward and upward events 0.90 0.96 0.99 McZdir Tkr1Zdir T. Burnett

  8. So, what about the MIP finder? • First attempt to use it in the classification tree was not a success. But this is a small fraction of the original population. Will look at it for these remaining events. • First, for all background: • CalMipZDir shows the fraction for which there is a measurment: • And for these, there is clear correlation with the actual incoming direction, both up- and down-going T. Burnett

  9. And now, the residual: Preliminary result disappointing: no apparent signal. McZdir Tkr1Zdir T. Burnett

  10. Next steps • Import Bill’s new cal tree definitions • Use v7r1 for training background: better ACD should help • 0.04 day already done at UW, we can do 0.01 day in a day. • Try MIP finder again, and review (with Bill, all the variables). T. Burnett

More Related