antiprotons lost above 10 degrees [message #17439] |
Thu, 30 October 2014 15:24 |
Karin Schönning
Messages: 65 Registered: August 2012 Location: Uppsala University
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continuous participant |
From: *physics.uu.se
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Dear colleagues,
I am studying the pbar p -> Lambdabar Lambda benchmark channel at 1.64 GeV (Lambda -> p pi-, Lambbabar -> pbar pi+). When "turning off" the MVD/GEM (to do tests for the scrutiny campaign) very few antiprotons are reconstructed above 10 degrees. Other particles (protons and pions) have a "band" with very low efficiency between 10 and 20 degrees (see attached pictures, hopefully the titels are self-explanatory).
I use ideal pattern recognition, and have tried with and without ideal hypothesis in the Kalman filter, with qualitatively the same result.
Before the summer I did the same exercise but got a different result, then tracks in this area were reconstructed.
Does anybody have an idea what the reason may be?
Best regards,
/Karin
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