Hello. While I am trying to get Offset of vertex by ZDC and BB, I noticed a couple curious things. Before I say anything, look at the table below for vertex offset and sigma relative to TPM1 track vertex. (Unit is cm.) RUNNUM ZDC(sigma) ZDCCFD(sigma) BB(sigma) 4482(90deg) 24.47(7.67) 64.4(6.71) -3.28(.80) 4525(90deg) 62.78(3.43) 13.88(4.0) -2.57(.86) 4640(40deg) 71.18(3.09) -6.82(4.26) -5.30(1.55) 4646(40deg) 71.00(3.76) -7.73(4.45) -5.49(1.78) 4713(90deg) 72.45(2.82) -5.94(3.76) -4.05(0.92) 5036(90deg) 74.66(2.93) -6.05(3.85) -4.00(0.79) The first surprise was that ZDC(normal) vertex is better than ZDCCFD vertex. Did someone work on slewing on ZDC this year? The another thing is ZDC Vertex is useless for RUN 4482. (I guess we knew that by considering how long it took to commission ZDC this year.) The last thing, which you could not tell from this table, is that the left and right signal was flipped in RUN 4482 and 4525. ( I was very surprised to see ZDC and ZDCCFD vertices are unti-correlated in those runs. ) Anyway, anyone should check the vertex offset before use. hiro
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