Hi,
we've met today to have a discussion with Alexander Ilychev on the current
situation of treating radiative effects in Blast, and to come up with a
task list of near-term goals.
Distinguish between code that calculates the total radiated cross section
for a process (integrated over all radiated energies) and a Montecarlo
generator that generates an additional explicit real photon photon along
with the particles of the considered process.
All subsequent codes calculate outgoing radiation from the lepton branches
only.
Mascarad - calculates the elastic cross section including radiation,
integrates over all photon energies
Polrad - calculates radiated inelastic (inclusive) cross section,
integrates over all photon energies
DGen+Mascarad - Blast generator for radiated elastic events, accounting
for helicity dependence, additional real photon is
explicitly generated, energy not integrated. At present,
this generator produces a factor ~2 more radiative events
than expected from the original Mascarad code.
ElRadGen - Sasha's generator for elastic radiated events, like
Dgen+Mascarad, however still without polarization.
RadGen - Sasha's generator for radiated inelastic events (based on
Polrad)
RadGen has the feature that one can include a hadronic tensor of choice,
appropriate for the considered process
(elastic ->F1,F2; inelastic -> Maid; deuterium target ...). That way,
radiated generators can be constructed for both inclusive and exclusive
reactions.
RadGen/ElRadGen are Fortran generators, but it should be possible to link
them as objects to C++ code.
Recommended strategy:
-A wrapper should be written to include Sasha's generators into blastmc
or to produce root files from the RadGen/ElRadGen generators. Even if
not yet combined with Geant, at the generator level interesting features
can be studied.
-Vitaliy should try to understand and fix the normalization of the
radiative tail in the Dgen+Mascarad generator
-Sasha should implement polarization in ElRadGen, as a result ElRadGen and
Dgen-Mascarad generators should yield the same results.
-Sasha should provide RadGen based on Polrad and Maid.
-Finally, we should aim for realistic generators for each reaction
channel, inclusive and exclusive:
p(e,e')X, p(e,e'p)X, p(e,e'pi+)X, or
d(e,e')X, d(e,e'd)X, d(e,e'p)X, d(e,e'n)X, d(e,e'pi+)X, d(e,e'pi-)X,
-For p(e,e') and p(e,e'p) in the Delta region, it is important to
quantify the amount of radiative tail from the elastic process as this
would affect the asymmetries in the Delta region. For all other cases the
asymmetries between unradiated and radiated processes will change very
little, as the dominant part of the radiation is helicity independent.
Sasha is returning home on Thursday July 20, 2006. We will have a
follow-up analysis meeting next Wednesday to re-assess the tasks.
Best regards,
Michael
+-------------------------------------+--------------------------+
| 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 | |
+-------------------------------------+--------------------------+
---------- Forwarded message ----------
Date: Fri, 7 Jul 2006 11:57:49 -0400 (EDT)
From: Michael Kohl <kohlm@mit.edu>
To: "[BLAST_ANAWARE]" <Blast_anaware@rocko.lns.mit.edu>
Subject: Special Blast analysis meeting on Wednesday 7/12/2006
Hi,
though I had announced earlier to cancel next week's meeting, we decided to
still have one on Wednesday 7/12/2006 at !! 10:00 !! at Bates.
Note that 10am was chosen as there is a STAR collaboration meeting ongoing at
MIT with a session on spin physics in the afternoon.
By the time Sasha Ilyichev will be at Bates. The meeting will be about
radiative corrections at Blast:
-Summarize status quo of treating radiative effects in Blast
-Define task list, priorities, estimate of effort
Sasha will also give us a presentation on details of the procedure of handling
radiative effects in elastic and inelastic scattering at the collaboration
meeting on Friday 7/14.
Best regards
Michael
+-------------------------------------+--------------------------+
| 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 | |
+-------------------------------------+--------------------------+
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