P08id (Lambda->PK)


QA of Lambda Embedding with run 8 d+Au on PDSF (sample 15x)

Let's first check some event wise information. They look fine.

Then we check the randomness of the input Monte Carlo (MC) Lambda tracks. The 'phasespace' command in GSTAR is used for sampling the MC tracks. The input is supposed to be flat for pT within [0,8], Y [-1.5,1.5] and Phi [-Pi,Pi]. The 3 plots below show the randomness is OK for this sample. Please notice that Y is rapidity, not pseudo-rapidity.

Then we compare the dedx of reconstructed MC (matched) global tracks (i.e. the daughters of MC Lambda) to those of real (or ghost) tracks, to fix the scale factor. (scale factor = 1.38 ?)

Now we compare the nFitHits distribution of matched global tracks (i.e. the daughters of MC Lambda) and real tracks. The cuts are |eta|<1, nFitHits>25. For matched tracks, nCommonHits>10 cut is applied. From the left plot, we can see, the agreement of nHitFits is good for all pT ranges.

We check the pT, rapdity and Phi distributions of reconstruced (RC) Lambda and input (MC) Lambda. The cut for Lambda reconstruction is very loose. They look normal.

Here, we compare some cut variables from the reconstructed (RC) Lambda to those from real Lambda. Again, as you can see in these plots, the cuts are very loose for Lambda (contribution of background is estimated with rotation method, and has been subtracted). These plots are made for 8 pT bins (with rapidity cut |y|<0.75). The most obvious difference is in DCA of V0 to PV, especially for high pT bin.