1 / 11

Tracking for lepton physics

low - momentum. Tracking for lepton physics. Tetyana Galatyuk Goethe-Universit ä t, Frankfurt. The challenge…. No electron identification in front of tracking Background due to material budget of the STS

Download Presentation

Tracking for lepton physics

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. low - momentum Tracking for lepton physics Tetyana GalatyukGoethe-Universität, Frankfurt

  2. The challenge… No electron identification in front of tracking Background due to material budget of the STS Reduction of background by reconstructing pairs from g conversion and p0 Dalitz decay Radial vs. z position (eγ) and By along the beam axis Introduction

  3. Characteristic of the e+ and e- Invariant e+e- spectrum in 25 AGeV Au+Au collisions (b = 0, full phase space) Momentum distribution Introduction Opening angle distribution 1 signal decay / 400 background events

  4. Combinatorial background topology Small (moderate) opening angle  “close pairs” if there is no field Asymmetric laboratory momenta Introduction

  5. Momentum correlation plot plab identified e- vs. plab identified e+ plab identified e- vs. plab nrec e+ Introduction Track Segment Identified e+/- Identified e+/- Track Fragment

  6. Wish N1 : Increase the size of the tracking detectors STS1STS2 STS2 STS3 STS3 STS4 x vs. y position of the extrapolated tracks Wish N1 Done! By now standard geometry

  7. Wish N2 : The choice of the proper magnetic field Trade: Acceptance vs. Resolution Currently a scaling of the filed is used. Our choice is 70% of the nominal field value Dp as a function of the magnetic field value Wish N2

  8. Wish N3 : Good tracking performance Reconstruction efficiency ~93% (p < 1 GeV/c) Momentum resolution < 2% Number of primary tracks with momentum < 500 MeV/c increased by 26% Reconstruction efficiency Momentum resolution Wish N3

  9. Wish N4 : Field free region between the target and 1st MVD Distance to closest neighbor hit in the 1st MVD station • Excellent double-hit resolution (<100mm) provides substantial close pair rejection capability • A realistic concept to suppress the field between the target and first MVD station has to be worked out Wish N4 With magnetic field = 30% of its nominal value

  10. Wish N5 : Refined field profile in the target region RICH ~ 0 kG target ~ few kG ~ 7 kG Vertical magnetic field strength (i.e. By) along the beam axis • Magnetic field map was developed (E. Litvinenko) • Problems with the tracking, most likely do to the strong field gradient at around 10 cm downstream of the target? • Trade: • Suppression of delta-electrons vs. opening of close pairs Wish N5

  11. Summary Past: Optimize tracking performance for tracks with momentum < 1 GeV/c Changes to the the detector setup Present: Proposed STS geometry is “standards” by now High track reconstruction efficiency for low-momentum tracks Future: Tracking within the field free region between the target and MVD 1 Track reconstruction with MVD (using the 3/4 MVD setup) Reconstruction of the g conversion on the detector material (using KF article) Thank you

More Related