Hello. What do you mean by the mean ZDC vertex itself? Do you want to know if I can see this dependence without comparing to other vertex? If so, I can not answer that question. Since the real vertex distribution is very wide (sigma ~= 80 cm or so), it is not easy to see this unless comparing to the other detectors. On the other hand, after manually fixing the vertex of ZDC and BB to align to the TPM1 vertex, I have the symmetric dN/deta distribution for silicon, which is very sensitive for vertex location. So, I am inclined to think that it is coming from ZDC. However, if you still suspect the other detector is the cause of this dependence, talk to Bjorn or someone who is working on TPM1 vertex if TPM1 has any multiplicity dependence. Hiro On Mon, 19 Mar 2001, Michael Murray wrote: > Dear Hiro, > is the mean ZDC vertex itself multiplicity dependent? > It is possible that their is a problem with slewing. I am working > on setting up the ZDC database and putting more slewing corrections > in. > Michael > > Quoting Hironori Ito <hito@students.phsx.ukans.edu>: > > > Hello. The figure includes any events which ZDC and TPM1 cluster > > vertex exist. (I have to have TPM1 since that is what I am comparing > > with.) There is no additional cuts. Unless the TPM1 cluster vertex > > has > > multiplicity dependence, which I have not heard such a dependence, it is > > coming > > from ZDC vertex. Maybe, the slewing correction is not quite right??? > > > > Hiro > > > > On Mon, 19 Mar 2001, Michael Murray wrote: > > > > > Dear Hiro, > > > I guess that the figure was made only > > > for events in which the BB and the TPM1 vertex > > > failed. If so the effect you see could be induced > > > by an (multiplicity dependent) > > > inefficency in the vertex algorithm of > > > these detectors. Could you please remake the > > > same plot for an unbiased sample of events from > > > the same run. Ideally that would be just ZDC triggers. > > > Yours Michael > > > > > > Quoting Hironori Ito <hito@students.phsx.ukans.edu>: > > > > > > > Well. I have another thought about fixing manually. I can not > > > > fix manually since I only use ZDC vertex when I do not have good > > vertex > > > > from BB or TPM1. This means that I can not fix ZDC since I do not > > have > > > > any other reference to fix ZDC Vertex. > > > > > > > > hiro > > > > > > > > On Fri, 16 Mar 2001, Hironori Ito wrote: > > > > > > > > > Hello. I have a question. I remember reading the e-mail about > > > > > ZDC_Vertex do not have Multiplicity dependence. Well, I think it > > is > > > > > there. Look at the figure "ZDC_TPM1_vertex.ps" in > > > > > "http://pii3.brahms.bnl.gov/~hito". The figure is produced from > > > > > run 2336. In this figure, the vertical scale is > > > > > ZDC vertex - TPM1 (cluster) vertex, and the horizontal scale is > > BB > > > > > Mult. Of cause, it is possible that BB Mult is wrong. But, if I > > use > > > > > other mult such as Si and Tile mult, I see the same thing. > > > > Furthermore, I > > > > > do not see this much dependence from BBVertex - TPM1 Vertex > > although > > > > > BBVertex have other problem. Can someone look at this? The fix > > is > > > > > needed since multiplicity in Si can easily is affected by 3-4 cm > > shift > > > > of > > > > > vertex. Until it is fixed, I will manually (in my own code) fix > > > > ZDCVertex > > > > > to align to TPM1 vertex. > > > > > > > > > > Hiro > > > > > > > > > > > > > > > > > > > > > > > > > > Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899 > > > > > > > > > Michael Murray, Cyclotron TAMU, 979 845 1411 x 273, Fax 1899 >
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