final state study Jaewon Park University of Rochester Vittorio Paolone University of Pittsburgh MINERvA Collaboration Meeting, Sep 13-15, 2007

2 Overview Geant3-based minerva MC simulation Study reconstructed track with nc-res sample. (Jaewon) Study reconstructed track in e CC events (Vittorio) Track reconstruction efficiency, dE/dx, track length, and etc Attemp to tune tracker Study particle identification

3 Tracker Filter requirements Definition  View: X, U, or V  HitPlane: Plane that has hits Minimum number of HitPlanes  View that has largest number of hitPlanes >= 3 hitPlanes  Sum of hitPlanes from the other two views >= 3 hitPlanes Minimum number of hit in a view  Number of hits per view > 3 Maximum cluster size  Number of strips per plane in a cluster ≤ 4 (128) cluster single hit

4 Digit hit – example event xview uview vview Low energy, large angle gamma2 has a few hits but it doesn’t look like that poo r track. Tracker didn’t fit gamma2 because it di dn’t meet the requirement Apply different loose requirement for s hort track?

5 Number of hitPlane for gamma Two gamma event sa mple By looking raw digit h its, simply check hitpla ne distribution This is before applying Kalman Filter E(g)>120MeV

6 Number of reconstructed gamma tracks gamma1gamma2 gamma1gamma2 After Before Modified tracker he lped more on gamm a1 but not much on gamm2 Gamm1,gamma2 is order gammas by tr ue energy scale. Before: original trac ker After: modified trac ker that allows gaps in hit cluster

7 Gamma track efficiency BeforeAfter allowing gaps in hit cluster

8 Gamma track efficiency With trackable normalization Original events Event satisfies hitPlanes>2 Reconstructed event

9 Proton track efficiency NC-RES events Almost no difference before and after allow ing gaps in hit cluster.

10 Pi0 mass reconstruction using gamma track This is an optimal case: Two gamma tracks are reconstructed Not too much difference before and after After Before

11 Gamma track efficiency as function of angle It seems that tracker o nly processes forward tracks. Efficiency drops as th eta angle increases.

12 dE/dx (energy deposit sum)/(reco track length) NC-RES events Broad distribution except muon.

13 Average cluster size Before/After modificati on on tracker to allow g aps in hit cluster within a plane I expected that average cluster value correspond s track fuzziness roughl y when track angle to z- axis is small But most of track has al most always 2 strips and it can have more than 2 when it showers After Before p p Average cluster size = (total nStrips)/(number of coordinate)

e flux (LE v19) files now accessible in MC (Geant3 version) Nu-e Energy (GeV)

Electron Reconstruction Efficiency Integrated over all energies: ~82% Event Sample: n e CC

Large cluster Size (# of strips used in layer) a go od discriminator for electrons (and gammas) ElectronsPion Protons Last 3 rd of track First 2/3’s of track Using ratio of cluster size from last part of track to first part of track as a cut one can easily achieve an electron ID efficiency of ~50% and a rejection of hadrons ~1/200.

17 Summary Checked track reconstruction efficiency from e CC and NC-RES interaction.  Need to study further to tune tracker. Cluster size(nStrips) seems good discriminatio n (track vs. shower) for particle ID.