Effect of Fiducial Cut on All Backgrounds Plot on the left considers - - PowerPoint PPT Presentation

Effect of Fiducial Cut on All Backgrounds

• Plot on the left considers the effect of a fiducial cut (equal on all sides of the TPC) on the

signal/sqrt(background)

• Plot on the right considers the same cut but only for pi0 events where the second mcshower

is > 0.9 contained.

• Point of the plot on the left is to show that applying a fiducial cut on pi0 events where both

mcshowers are contained does have a positive effect but that this positive effect is superceded by other backgrounds

Distance Between Reco-Shower Vertex and Reco-Nu Vertex

• Considering only background events where the reco-shower has it’s largest charge

contribution from an electron mcshower (i.e. a “well reconstructed” electron reco-shower).

• Note that requiring this selection leaves only 40 events in the background sample (low

stats).

• There are some electron shower events where the distance between the reco-shower vtx

and reco-nu vtx is larger. This is likely due to a failure in the vertex algorithm.

• Applying a cut at lower distances increases sig/sqrt(back) but also decreases efficiency

considerably.

Distance Between Reco-Shower Vertex and Reco-Nu Vertex

• Considering only background events where the reco-shower has a non-zero charge

contribution from an electron mcshower.

• Similar result to looking at only “well reconstructed” electron reco-showers. Can apply a

low distance cut but there are some events at larger distances.

Shower Energy / Shower Length

• Considering only background events where the selected reco-shower has it’s largest

charge contribution from a photon mcshower that is the child of a π0 and the second child mcshower makes its largest charge contribution to the same selected reco- shower (two π0 showers merged into one).

• Hoping having two mcshowers merged into one reco-shower would have a larger

“energy density” than a single mcshower, however distributions are very similar. Tried cuts in both directions.

Delta Mass Using Truth Information (GENIE level)

• Plot on the left considers only Δ+ events where the proton and photon children exit the

nucleus and are the only particles to exit the nucleus.

• Lower energy bump on the left side of the distribution.
• Plot on the left has same selection requirements plus a further 0.22 GeV energy cut on

protons which removes low energy bump.

• Δ mass = 1.232 GeV