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items: how to convert kinematic variables from lab frame to cm frame in root
items: Re: how to convert kinematic variables from lab frame to cm frame in root

how to convert kinematic variables from lab frame to cm frame in root
type: item
description: Hello everyone, I know the Theta distribution of two body decay reaction in the laboratory frame.I need to convert Theta_lab distribution in to Theta_CM distribution for my analysis. For this , I have searched in the ROOT user guide but unfortunately I could not see any functionality there for that. How to convert different kinematic variables from lab frame to cm frame using root? Is there any functionality available in root for this conversion? Thanks
creator: Ajay Kumar
date: 2013-06-03T06:56:10-00:00

Re: how to convert kinematic variables from lab frame to cm frame in root
type: item
description: Hello, There are two situations: A) If you do analysis, there is the RhoBooster class which helps transforming the particle candidates between LAB and CM. B) You use TLorentzVector: There is the possibility to boost it with the CM momentum. (see also http://root.cern.ch/root/html534/TLorentzVector.html) Cheers. Ralf
creator: Ralf Kliemt
date: 2013-06-03T07:32:17-00:00

Re: how to convert kinematic variables from lab frame to cm frame in root
type: item
description: Hi Ajay, just a small remark: I also had to calculate this for lmd fitting. However my function calculates the 4 momentum transfer from the theta angle in the lab frame. You can see it here http://cbmroot.gsi.de//panda_doc/daily/html/classPndLmdDPMAngModel1D.htm l#ab105732897c38a7fa0aaf679dcb2bd11 Maybe this is of some use.. Best regards, Stefan
creator: Stefan Pflueger
date: 2013-06-03T13:19:27-00:00

Re: how to convert kinematic variables from lab frame to cm frame in root
type: item
description: This means that, if you have a collision along z axis, you can calculate the beta of the center of mass (betacm), and transform one TLV from lab to cm you have just to do: tlv_lab.Boost(0., 0., betacm);
creator: StefanoSpataro
date: 2013-06-03T17:31:02-00:00

Re: how to convert kinematic variables from lab frame to cm frame in root
type: item
description: Dear All, Thanks to all of you. I have boosted Lambda and AntiLambda from lab to cm frame using TLorentzVector. I have attached macro here.Please see it once, Am I doing correct ? Please help me. Thanks
creator: Ajay Kumar
date: 2013-06-25T07:18:03-00:00

Re: how to convert kinematic variables from lab frame to cm frame in root
type: item
description: No, it is not correct. First of all, you have to calculate the betacm from the initial particles (the target proton at rest and the projectile antiproton), and not from the supposed reconstructed lambdas. Second, if your CM is traveling at betacm, in order to have the coordinates in the CM frame you have to boost them of -betacm.
creator: StefanoSpataro
date: 2013-06-25T08:20:04-00:00