1 / 11

Investigation of Decay Length Error Outlines in Charm Measurements

Explore a comparison between decay length error outlines in charm measurements using different methods for determining secondary vertex position. Verify the agreement between slength and Lxy measurements and propose potential improvements. Test the efficiency of using slength and its error as substitutes for Lxy. Utilize data from real pT D0 in hijing for further analysis.

haley
Télécharger la présentation

Investigation of Decay Length Error Outlines in Charm Measurements

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. Investigation of cut slength/error

  2. outlines • In many papers about charm measurements, a cut on the decay length significance is used. • For ex : http://www-zeus.desy.de/physics/phch/conf/ichep06/hfl/9/ZEUS-prel-06-016.ps • The decay length is defined as :

  3. D0Tree • What we have in D0Tree is the length from TCFIT and its error • I also calculated Lxy (with the same definition) using the helix swimming to determine the secondary vertex and included in the tree • But I don’t calculate/include the errors • Idea : as this cut was used in another experiment (and has shown its efficiency), try to use a similar one • Test : compare slength from TCFIT with Lxy • I’m using a pure D0 sample

  4. No cut on probability

  5. Prob>.01

  6. Prob>.1

  7. Prob>.5

  8. comments • Using at least a minimal cut on probability of TCFIT, slength and Lxy seems pretty agree in the ‘physical’ range of D0 decay length (<1mm) • Lxy shows some large values : can look if using another method to determine the secondary vertex position (Kfparticle for example) gives better agreement • can use slength and its error as a substitute to Lxy. • Next : verify with the realp pT D0 in hijing

  9. Slength/error vs pT of D0 <slength/error> = 0.26 + 0.24pT  slength/error = 1.38 + 0.16pT

  10. Slength/error vs pT of D0 (power law pT) • Linear fits not really good because of law statistic

  11. HERA-II specifications (ZEUS detector • ep collisions • Reconstruction of D+ • Pre selection of tracks (pT(kaon)>.65GeV , pT(pions)>.45GeV) • D+ candidates with pT>3GeV/c only accepted • Vertex detector : • 600 single sided silicon detectors in 3 barrels

More Related