coulomb excitation data analysis codes; gosia 2007 - Physics and ...

gosia < 2-make-correction-factors.inp3. Generate the q-Parameter Map (3-make-q-parameter-map.inp)One small change (from the simulation demo) has been made in OP,GOSI in the sub-option ME. Matrixelement5(fortheE2transitionfromstate3tostate4infigure 13) has been coupled to matrix element 3(fortheE2transitionfromstate2tostate3). Thisisdonebyflagging the second field (the index of the finalstate) with a negative sign and replacing the upper and lower limits with the indices of the “master” matrixelement (2,3). This is a useful tactic when there is insufficient data to fit matrix elements individually andthe ratio of two matrix elements can be calculated (as in the matrix elements of a rotational band with aconstant intrinsic quadrupole moment Q 0 ).The “q-parameter” map (Section 4.2) is created by modifying the input as follows. OP,MAP is inserted atthe end of OP,YIEL (just before OP,INTG). It takes no arguments and is immediately followed by OP,EXIT.NTAP can be set to 0, since experimental data are not necessary for this step.Any time the ranges over which matrix elements are allowed to vary are changed, OP,MAP should be runagain.File number 7 is assigned to firstfit.map. After execution of this step, it should contain the q-parameter mapappropriate for this fit. Attaching file 7 to the minimization input (step 4) will allow Gosia to read it.4. Fit the Adjustable Matrix Elements (4-minimize.inp)In step 4, the variable NTAP in OP,YIEL is set to 4, so that Gosia uses the “corrected yields” to calculatedchi-squared.OP,INTG is not necessary, since the corrected yields will be compared to the point yields at each step ofthe minimization. OP,MINI is inserted following OP,YIEL. There are a number of user controls (maximumnumber of iterations, derivative of the matrix element vector, etc.) that define the criteria for convergenceand choices of the search method in the parameter space. The best choice will be case-dependent. Refer tosection 5.17.Issue the commandgosia < 4-minimize.inpThe progress of chi-squared will be sent to standard output until Gosia satisfies the convergence criteriaor reaches the maximum number of iterations chosen by the user. The output should look similar to thefollowing.OPENED 4-minimize.outIO-num = 22 UNKNOWN FORMATTEDOPENED 4-minimize.inpIO-num = 25 UNKNOWN FORMATTEDOPENED det.gdtIO-num = 9 UNKNOWN FORMATTEDOPENED firstfit.mapIO-num = 7 UNKNOWN FORMATTEDOPENED firstfit.corIO-num = 4 UNKNOWN FORMATTEDOPENED currentbestset.bstIO-num = 12 UNKNOWN FORMATTED*** CHISQ= 0.313370E+02 ****** CHISQ= 0.204481E+00 ***More details of the progress toward the minimum are given in the *.out file. For instance, if the search hita limit in one or more matrix elements, this will be reported as a warning to the user that either the rangeis too narrow, or a matrix element is not sensitive to the data. At the conclusion of the fit, the best setof matrix elements are written to file 12, currentbestset.bst. In the second iteration (steps 5 - 7), Gosiawill begin at this new starting point in the parameter space. Steps 5 - 7 are a repeat of steps 2 - 4 withpoint-correction factors calculated (presumably) closer to the true chi-squared minimum.163