[Jlab-sidis] SIDIS working group meeting

[Harut Avakian]

On 3/2/15 10:44 AM, Christian Weiss wrote:
>
> Harut, Alexei, All,
>
>
> 1) Yes, it would be good to discuss how to set up a database for the SIDIS data.
> Just one suggestion: Sylvester Joosten (now Temple U.) has set up a very nice
> database for the HERMES multiplicity data
>     www-hermes.desy.de/multiplicities
> which is fully documented and allows you to access different bindings
> (fully differential, low statistics -- partly integrated, higher statistics).
> I have used it a lot and find it very convenient.
> Sylvester is now at Temple and could easily come to JLab.
> We should ask him to tell us about his database at one of our meetings;
> perhaps just schedule a meeting when he will be at JLab anyway.
> Sylvester, are you on this mailing list?

Dear All,
All those databases are great.  Their use is, however limited to certain 
applications.
The concept of the database we need is more complex, than just storing 
certain data files and making plots from them.
We are currently discussing with HERMES colleagues, storing 4vectors of 
all tracks of all events, in some standard
format which we use also to store all CLAS6 and CLAS12 data.
When we will define the
extraction framework we will have much better understanding on how and 
what to store.

>
> 2) Independently of this, we should continue with the discussion of overall
> analysis goals and strategy. One issue that needs to be discussed/clarified
> is the specific purpose/role of "MC" in the different tasks. It seems that
> we used the term "MC" for two separate tools that are quite different:
>
> (a) "small:" Event generator + phase space integration for SINGLE-INCLUSIVE
> scattering (resolving only the identified SIDIS hadron), for extraction and
> verification of PDFs/TMDs. This is a well-defined problem, and there is
> a lot of experience from different sides.
>
> (b) "large:" Full dynamical MC (based on Lund string fragmentation or other
> dynamics) to generate the FULL hadronic final state, including hadrons that
> are not intended to be identified in the single-inclusive SIDIS analysis
> (such as target fragments, slow particles in the current jet). I.e., the full
> "underlying event," as it would be called in high-energy physics. This requires
> a much more broad-based discussion re what dynamics one can sensibly implement,
> and how to make this dynamics consistent with "pre-existing" distribution and
> fragmentation functions.
>
> It did not help our initial discussions that these different purposes were
> not clearly identified, and that we used the term "MC" interchangeably for
> rather different purposes. It would be very worthwhile if this could be
> clarified once and for all.

Previous meetings were dedicated to the role of a) and b)  (mostly a) 
was discussed) in different procedures we want to use.
We seem to converge on a) to be used in the  tests of extraction 
framework mainly, and  b) being a much bigger project which can be a 
candidate for a
topical collaboration itself.
The request to all,  was  to formulate in a short presentation their 
ideas about the extraction framework, possible applications of either 
MC, and  ideas how to develop them.
You are very welcome to present your ideas about  "how to make the 
dynamics in b) consistent with "pre-existing" distribution and 
fragmentation functions".

Best,
Harut


>
> Ch.
>
>
> ----- Original Message -----
> From: "Alexey Prokudin" <prokudin at jlab.org>
> To: jlab-sidis at jlab.org
> Sent: Sunday, March 1, 2015 1:24:18 PM
> Subject: Re: [Jlab-sidis] SIDIS working group meeting
>
> Dear Harut, All,
> This Wednesday is fine with me. I would propose to start
> thinking of some practical issues along with continuing with "formal"
> presentations.
> If we continue with presentations only the project will never start.
>
> My proposal would be:
>
> After the talk by Ted, let us discuss the outstanding and never resolved
> issue of creating a database for the SIDIS/TMD data. For this sake we
> also need to invite people who actually have experience in cerating
> databases. Wally is one of them
>
> Best,
>     Alexei
>


-- 
___________________________________________________________________________
Harut  Avagyan                           e-mail  - avakian at jlab.org
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