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Hi all, here is an update on the D** modeling with what I learned from David Lange. What I take from David's email below is (please feel free to disagree with my conclusions...): *Request new SP5 and SP6 (D** only) to replace the D** in the generic: This seems to work with a one-line-fix in the dec file for SP6, but not for SP5 (since SP5 is release 12 if I am not mistaken. I am checking with David to be sure.). I guess we would feel uncomfortable to use SP6-D** for all our D** for the real analysis as far as detector response and backgrounds are concerned. *Produce our own truth MC to produce weights: This should work fine if we can get EvtGen running in a release suitable for SP6. We could produce all we want: - SP8 by using David's switch - SP6 as default - SP5 by reverting the changes between SP5 and SP6 by hand (We need to change the dec file and evt.pdl for this.) I guess we should talk about this in the meeting tomorrow (I'll have to leave at 9:25 am.). Cheers, Kerstin Here is the actual email from David: Hi Kerstin, Sorry for the delay: > Thanks, David! > > Please allow me to ask another technical question: So if we try to > produce SP6-like D** (we are interested in the mass distribution > of B->D**lnu, so I am sure we are affected by changes in the lineshape) > and SP8-like D**, where do the two differ at the technical level, > what do we need to pay attention to? Can the change between the > two levels made at the dec-file level? (If so, starting with which > tag of EvtGen does that work?) Or do we need two different > version of the code (If so, which piece?)? The fix in the default MC is between r18 releases and r14 releases. The current sp6 release can be used to generate the buggy version and 'fixed' version by adding SP6LSFix <particle name> in the decay file. In sp8, it is not possible to go back to the sp6 buggy shape. There is a known residual problem in sp8 that may affect you described in https://www.slac.stanford.edu/babar-internal/BMO/BbrMeetingOrganizer/meetingDetails.html?mtgnum=437[1] Cheers- David > > Thanks for your help, > Kerstin > > On Mon, 9 Oct 2006, David Lange wrote: > >> Hi Kerstin >> >> The problem discussed in this thread affects all particles. Depending on >> the mass/width/decay mode you are looking at, it may or may not be an >> issue. Until October 1, the easiest way was to request mc with a >> somewhat modified decay file. Now, the easiest thing is likely to get >> some sp8 and look at reweighting. >> >> david >> >> >> Kerstin Tackmann wrote: >>> *** Discussion title: Event Generators >>> Email replies to [log in to unmask] must include: >>> In-Reply-To: <"/event_gen/498/2/4"@babar-hn.slac.stanford.edu> >>> Subject: ...change this to be about your reply. >>> >>> Hi David, >>> >>> does this affect only the D_0^*0, or also the D_0^*+? >>> Does it affect the other D**? >>> >>> Our analysis uses SP5 and SP6 - what is our best option >>> to get the correct lineshape for the D**? >>> Reweighting probably can at most do part of what we >>> want because I remember the maximum allowed deviation from >>> mean mass is too big for some D** in SP5. >>> >>> Thanks, >>> Kerstin >>> >>>> Hi Liaoyuan >>>> >>>> I guess you mean 'between sp6 and sp8' below. As your plot illustrates >>>> nicely, some factors were missing in sp5/sp6 lineshapes, in this case, >>>> most importantly phase space factors. If you add the appropriate phase >>>> space factors to your BW curve, you should get the sp8 curve. >>>> >>>> david >>>> > ----------------------------------------------------------------------- [1] https://www.slac.stanford.edu/babar-internal/BMO/BbrMeetingOrganizer/meetingDetails.html?mtgnum=437