1 / 7

Photon selection for first PHOS data in Run8

Photon selection for first PHOS data in Run8. DongJo Kim. Things to look at. AliPHOSGeometry Cocktail generator AliGenCocktail * gener = ne w AliGenCocktail () ; Charged particle veto detector which has two option : a pre-shower gas detector named PPSD

aglaia
Télécharger la présentation

Photon selection for first PHOS data in Run8

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. Photon selection for first PHOS data in Run8 DongJo Kim

  2. Things to look at • AliPHOSGeometry • Cocktail generator • AliGenCocktail*gener = ne wAliGenCocktail(); • Charged particle veto detector which has two option: • a pre-shower gas detector named PPSD • a multiwire proportional chamber named CPV. • Reconstruction • Clusterizer procedure (AliPHOSClusterizer) • TrackSegmentprocedure (AliPHOSTrackSegmentMaker) • Particle identification (AliPHOSPID)

  3. Photon Identification in PHOS • CPV ( Charged Particle Veto ) • defines a reconstructed particle as a neutral if there is no charged • TOF ( Time of Flight ) • the time between collision and  arrival to PHOS • PCA ( Principal Component Analysis ) • reduce the number of correlated parameters to new uncorrelated parameters but fewer in number

  4. CPV “ EMC rec. point is identified as a neutral particle if there is no charged track projection within (Delta-x,Delta-z) rectangular." This neutral isolation criterion is defined by the distance between the EMC rec. point and the projection of a charged track onto the EMC surface. As far as we rely only on the CPV information about charged tracks, we calculate the projection of the CPV rec. point into the EMC along the straight line coming from the IP. The worst distance is that one for hadrons.

  5. TOF Different time resolutions has been applied to the TOF selection

  6. PCA • 7 correlated  parameters: • lambda0, lambda1, dispersion,  sphericity, digits multiplicity, maximal cluster energyand cluster core energy • All this parameters are reduced to 2 uncorrelated ones. • Ellipse = d *e-arg , • where arg = [(x-x0)/a]2+[(y-y0)/b]2+c*(x-x0)(y-y0)/a*b

  7. Photon ID efficiency

More Related