1 / 10

Status of analysis of leptonic decays in Nov08 ppeta run

Status of analysis of leptonic decays in Nov08 ppeta run. By Marcin Berłowski The Andrzej Soltan Institute for Nuclear Studies , Warsaw Collaboration & Analysis Meeting, Juelich 10-11.IX.2009. Short outline of short presentation. Nov 0 8 pp  pp  at 1.4 GeV PT10 numbers

cuyler
Download Presentation

Status of analysis of leptonic decays in Nov08 ppeta run

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. Status of analysis of leptonic decays in Nov08 ppeta run By Marcin Berłowski The Andrzej Soltan Institute for Nuclear Studies, Warsaw Collaboration & Analysis Meeting, Juelich 10-11.IX.2009

  2. Short outline of short presentation • Nov08 pppp at 1.4 GeV PT10 numbers • Decay channel  and some expectations • Indication of e+e- pairs • Future plans and final conclusions

  3. Data from November 2008 runs • Reaction: pp→pp at 1.4 GeV • Four triggers for charged decays (10, 17, 21,30) PT10 trigger • Trigger definition - [fhdwr2*frhb2*ecrl*Vfvh1] • Unprescaled • High energy deposited in both sides of SEC • It didn't choose between  decays: →e+e-e+e-, →e+e-, →e+e-, → • ~1100 runs each around 120k of events (preselected with conditions FDC>=2 & CDT>=2) • 2 weeks of data taking All results below based on 1% of above

  4. Selection of → events • Particle selection: - Two charged from FD closest in time, within 3°-18° - Two photons giving greatest opening angle on a XY plane • Time cuts: - Time coincidence between FDC, CDN (each of them in [-25,+35]ns bounds) - No PS hits in the time of neutral tracks - For each of FDC, CDN: (max_time – min_time) in 20 and 50 ns respectively

  5. → Data IMgg [GeV] Cut: 0.5 < MMpp < 0.6 GeV

  6. → IMgg Cut: cdn=2 MMpp Data

  7. Expectations • We see 97k ev with at least 2 • Raw estimation of number of eta's from IM pick (gaussian fit) ~ 3060 ev (blue numbers multiplied x102 will be for whole data sample) • After reconstruction efficiency & detector acceptance for e+e- we expect ~ 36 ev • We know from previous CELSIUS/WASA analysis that we have conversionfrom , background in ratio ~1:2 in respect toe+e- channel. Finally ~ 54 ev

  8. Indication of e+e- pair(s) Data MC

  9. Final conclusions and „to do” list • Only 1% of all data collected with trigger PT10 was allready analyzed. • Whole data sample analysis will be started soon. • The number of expected events will be hopefully enought for setting new, better value for BR of e+e-.

  10. Thank you for your attention

More Related