 |
 |
Hi Bob, new plots are posted here: http://babar-hn.slac.stanford.edu:5090/hn/aux/petrella/SF.ps now the agreement in the mx and P+ spectra has improved ciao, Antonio [log in to unmask] ha scritto: > Hi Antonio, > > For the record, now that we have the moments fixed for the three > different functional ansatze can you remake the plots of the kinematic > variables that you did previously? > > Bob > > On Fri, 6 Jul 2007, Antonio Petrella wrote: > >> Hi all, >> I've recalculated the parameters for the three ansaetze. >> Here are their values: >> >> -- Exponential -- >> a = 1.32669 >> 0th moment = 1 >> 1st moment = 0 >> 2nd moment = 0.165477 >> >> -- Gaussian -- >> c = 0.3057134 >> 0th moment = 1 >> 1st moment = 0 >> 2nd moment = 0.165495 >> >> -- Roman -- >> rho = 0.2667075 >> 0th moment = 1 >> 1st moment = 0 >> 2nd moment = 0.165480 >> >> New plots for the shape functions and their cumulative distributions are >> posted at: >> http://babar-hn.slac.stanford.edu:5090/hn/aux/petrella/SFplot_new.ps >> I would say that now we can trust efficiencies calculated using these >> parametrizations. >> >> ciao, >> Antonio >> >> Luth, Vera G. wrote: >>> Thank you Antonio, >>> This clearly explains the problem. As you change the ansatz for the SF, >>> the parameters have to be adjusted! >>> >>> Ciao >>> Vera >>> >>> -----Original Message----- >>> From: [log in to unmask] >>> [mailto:[log in to unmask]] On Behalf Of Antonio >>> Petrella >>> Sent: Thursday, July 05, 2007 6:56 AM >>> To: vub-recoil >>> Subject: Shape Function form >>> >>> Hi all, >>> >>> as Kerstin suggested in her message >>> http://babar-hn.slac.stanford.edu:5090/HyperNews/get/rev-SemiLep-06-04/1 >>> 7/2.html, >>> I checked the first moments for each shape function ansatz (exponential, >>> >>> gaussian and roman) that I have implemented in my private version of >>> EvtGenModels in order to compute the correct phase space acceptance >>> needed for the calculation of tag efficiency when estimating the >>> uncertainties due to the different ansateze. >>> >>> The implementation of the SF formulae has been copied from the package >>> VubHybridModel. >>> >>> For each ansatz the same values for mb (4.6586) and a (1.32669) >>> parmeters are used, only the form is changed. >>> >>> We know that the 0th moment (A0) has to be equal to 1, the 1st moment >>> (A1) has to be equal to 0 and the 2nd moment (A2) has to be equal to >>> 1/3*mu_pi^2. >>> >>> Here's what I get: >>> -- Exponential form -- >>> A0=1 >>> A1=0 >>> A2=0.165477 >>> >>> Being A2 = (mB-mb)^2/(1+a), I could double check that is correctly >>> computed since I provide the masses and the a parmeter from the >>> decay.dec file: mB=5.2791, mb=4.6586 and a=1.32669, giving A2=0.165458. >>> >>> -- Gaussian form -- >>> A0=1 >>> A1=0 >>> A2=0.089637 >>> >>> -- Roman form -- >>> A0=1 >>> A1=0 >>> A2=0.086776 >>> >>> A2 is changing so mu_pi^2 is changing too. >>> >>> I have also made plots of the shape functions: >>> http://babar-hn.slac.stanford.edu:5090/hn/aux/petrella/SFplot.ps >>> one can easily see that they're pretty different. >>> >>> I'm a bit puzzled: should the a parameter be equal for all the forms? It >>> >>> seems, in this case, that there is no way to have mu_pi^2 unmodified. >>> >>> Do you have any comment on this? >>> >>> cheers, >>> Antonio > > \\\\\\\\\\\\\\\\\//////////////////\\\\\\\\\\\\\\\\\////////////////// > / Robert V. Kowalewski \/ Dept. of Physics and Astronomy \ > \ particle.phys.uvic.ca/~kowalews /\ University of Victoria / > / Tel: (250)721-7705 \/ P.O. Box 3055 \ > \ Email: [log in to unmask] /\ Victoria, BC V8W 3P6 / > /////////////////\\\\\\\\\\\\\\\\\\/////////////////\\\\\\\\\\\\\\\\\\ >