hi,
the analysis has finished for runs 3063-3105. unfortunately, there is
no substantial improvement in resolution after the bugfix.
before after (sigma)
p .05592 .0564 GeV
th .09207 .9118 deg
phi 1.112 1.103 deg
z 2.179 2.172 cm
--chris
Chris Crawford wrote:
> hi,
> i checked in the fixes to v2, and also b2_17 and b2_18 bugfix
> branches. i am currently making new ntuples for runs 3063-3109 with
> the fixed version 2_18 to test the improvement in resolution.
> --chris
>
> Douglas Hasell wrote:
>
>> Hi,
>>
>> Aaron has pointed out an error in the time to position algorithm.
>>
>> In order to simplify the algorithm I parameterized the time to
>> position relationship for super-layer=0 and then used symmetry
>> arguments to use the same parameterization for super-layer=1.
>> However, I forgot to flip one symmetry axis.
>>
>> So, somewhere in the code (Tong took the code I sent him and
>> changed it to conform to whatever conventions you are using) there
>> should be something like this:
>>
>> float WC_pos_vs_t( int wire, int super, float theta, float bfield,
>> int pm,
>> float t ) {
>>
>> ...
>> ...
>> ...
>>
>> // If this is superlayer 1 reverse the wire number and field.
>>
>> if( super == 1 ) {
>> wire = 2 - wire;
>> bfield = - bfield;
>> }
>>
>> The above lines (or equivalent after Tong changed things)
>> should also reverse the track angle and look something like this:
>>
>> // If this is superlayer 1 reverse the wire number, track angle and
>> field.
>>
>> if( super == 1 ) {
>> wire = 2 - wire;
>> theta = -theta
>> bfield = -bfield;
>> }
>>
>> Could someone please change this in the appropriate place
>> since Tong is away and let everyone know when it is changed? Thanks.
>>
>> Also, Chris, its probably worthwhile redoing the ep analysis
>> as this will change things.
>>
>> Cheers,
>> Douglas
>>
>> 26-415 M.I.T. Tel: +1 617 258 7199
>> 77 Massachusetts Avenue Fax: +1 617 258 5440
>> Cambridge, MA 02139, USA E-mail: hasell@mit.edu
>
>
>
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