I took an initial look at the radiative corrections in MC, and
there are problems. I include two problem histograms: the first one
is just raw theta in the left sector. It has a significant peak with
structure around theta=0, which should not be present. If I had to
guess, I would say that the code is generating radiative kinematics
in the frame of the outgoing electron instead of in the BLAST frame
(although that does not make sense either, since you do see a small
tail above v=0.10 GeV^2).
The second is a histogram of the invariant mass W for 25 < th_e <
35 deg. Out of the 266406 events in the elastic peak (v < .010
GeV^2 or W-M < 5.6 MeV), there were only 45 events in the
radiative tail. The original code gives delta(.010)=0.804 and delta(.
4427)=0.978, implying 266406*(978-804)/978 = 47397 events in the
tail, up to only W=1150 MeV. Note: v = W^2 - M^2 is the
inelasticity (a parameter in MASCARAD).
Due to small statistics, I was unable to verify the shape of the
tail. Anyways, someone must correct these problems before this MC
can be trusted for radiative corrections. I will report on
corrections based on the original MASCARAD code at the next meeting.
--Chris
_______________________________________
TA-53/MPF-1/D111 P-23 MS H803
LANL, Los Alamos, NM 87545
505-665-9804(o) 665-4121(f) 662-0639(h)
_______________________________________
On Apr 13, 2006, at 07:42:09, Adrian T Sindile wrote:
> Hi Chris,
> Sorry I did not reply last night, I am trying a novel schedule -
> sleeping at night and waking up in the morning. :-)
>
> Here are the locations of my MC files:
>
> /scratch/bud05/adrian/radCorFixed/run?/event.coda, where ? stands
> for 1 to 4 (I used 4 different random seeds).
>
> I reconstructed them at:
>
> /scratch/bud05/adrian/finalBLAST/run?/
>
> Of course I used my ep_skim structure there and I never looked at
> lr, flr etc. But they were created at those locations and you can
> look at them.
>
> Thank you and sorry I did not get to this sooner.
> Adrian
>
> On Wed, 12 Apr 2006, Christopher Crawford wrote:
>
>> Adrian,
>> Can you please send me a description and the location of your MC
>> files, and crunches? I would like to test them against the
>> original MASCARAD code.
>> --thanks, Chris
>> _______________________________________
>>
>> TA-53/MPF-1/D111 P-23 MS H803
>> LANL, Los Alamos, NM 87545
>> 505-665-9804(o) 665-4121(f) 662-0639(h)
>> _______________________________________
>>
>>
>> On Apr 12, 2006, at 16:23:08, Adrian T Sindile wrote:
>>
>>> Hi Michael,
>>> I used channel 266 in all my simulations (with default cutoff),
>>> so the results I presented then should be valid.
>>> Thank you,
>>> Adrian
>>>> -Mascarad handling
>>>> +Mascarad channel "666" only produces tail, starting from low
>>>> energy
>>>> cutoff. Default is 10 MeV
>>>> +Use channel "266" (mixes Epel and Mascarad) for realistic MC
>>>> Sum of unradiated and radiated yield should reproduce total elastic
>>>> cross section (important to normalize radtail for inelastic
>>>> channels).
>>>> +The smaller the low-energy cutoff, the more the Mascarad part is
>>>> weighted (automatically in "266", however renormalization of total
>>>> cross section required). The cutoff can be chosen in the input
>>>> file.
>>>> +Cutoff should be smaller than the resolution, but large enough to
>>>> not cause numerical instabilities. Present default is 10 MeV,
>>>> resolution
>>>> is ~30 MeV.
>>>> +To-do-list for Mascarad users (Eugene, Adrian,...):
>>>> Run Epel+Mascarad ("266") for different low-energy cutoff values
>>>> and
>>>> compare MC yield with data (W spectrum). Find range of cutoff
>>>> values
>>>> for which MC/data doesn't vary, assuming realistic resolution (!)
>>>> +Tune the resolution such that MC best reproduces data. Tip:
>>>> look at
>>>> ratio MC/data versus W for all adjustments of cutoff and resolution
>>>> +Goal: By how much does the location of the W peak maximum bin
>>>> shift
>>>> compared to the unradiated peak position depending on the
>>>> resolution?
>>>> This result should be parametrized and separately accounted for
>>>> along
>>>> with energy loss of the proton when "residual kinematic
>>>> corrections" are
>>>> determined.
>>>> -Shifted acceptance
>>>> +Acceptance has not shifted in data reconstruction
>>>> +Discrepancy between data and MC at forward angles for d(e,e'p)n
>>>> and
>>>> d(e,e'n)p, see Eugene's and Adam's plots (meeting_060412)
>>>> +Tossing volume starts at 24 degrees which is too large, should
>>>> be 22
>>>> degrees or smaller
>>>> +VZ attributes discrepancy to the way the white generator
>>>> distributes
>>>> events in phase space, giving poor yield at small angles but I
>>>> don't
>>>> buy this
>>>> +Tossing volume should be at least as large as necessary to
>>>> cover all
>>>> resolution smearing.
>>>> +Unclear how hPz at smallest Q2bin is affected
>>>> +-------------------------------------+--------------------------+
>>>> | Office: | Home: |
>>>> |-------------------------------------|--------------------------|
>>>> | Dr. Michael Kohl | Michael Kohl |
>>>> | Laboratory for Nuclear Science | 5 Ibbetson Street |
>>>> | MIT-Bates Linear Accelerator Center | Somerville, MA 02143 |
>>>> | Middleton, MA 01949 | U.S.A. |
>>>> | U.S.A. | |
>>>> | - - - - - - - - - - - - | - - - - - - - - -|
>>>> | Email: kohlm@mit.edu | K.Michael.Kohl@gmx.de |
>>>> | Work: +1-617-253-9207 | Home: +1-617-629-3147 |
>>>> | Fax: +1-617-253-9599 | Mobile: +1-978-580-4190 |
>>>> | http://blast.lns.mit.edu | |
>>>> +-------------------------------------+--------------------------+
>>> --
>>> --------------------------------------------------------------------
>>> ----
>>> Adrian Sindile Room 205A, DeMeritt Hall
>>> Research Scientist phone: (603)862-1217
>>> Xenon Imaging Center & FAX: (603)862-2998
>>> Nuclear Physics Group email: asindile@unh.edu
>>> University of New Hampshire http://einstein.unh.edu/~adrian/
>>> --------------------------------------------------------------------
>>> ----
>
> --
>
> ----------------------------------------------------------------------
> --
> Adrian Sindile Room 205A, DeMeritt Hall
> Research Scientist phone: (603)862-1217
> Xenon Imaging Center & FAX: (603)862-2998
> Nuclear Physics Group email: asindile@unh.edu
> University of New Hampshire http://einstein.unh.edu/~adrian/
> ----------------------------------------------------------------------
> --
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