--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 Feb 21, 2006, at 16:24:52, Eugene J. Geis wrote:
> Hello BLASTer's,
>
> Please correct any of my assumptions or arguments as I am
> not an experienced MonteCarlo Generator and the directions
> I have received are sparse and unclear, most likely due to
> my inability to have a face-to-face conversation with a
> shared computer.
>
> Thesis:
> ----------
> Our kinematic corrections have been motivated by idealized
> assertions of the direct ep-elastic kinematic relations.
> This is, most likely, a false description and thus I am
> investigating the generation of ep-elastic events in the
> Monte Carlo. Hopefully this will allow me to more
> realistically describe the benchmark for appropriate
> kinematic corrections that will applied to subsequent data
>
> Disclaimers and Assumptions:
> --------------------------------------------
>
> #1: I have used "unradiated MC" without resolutions
> inserted. I believe that the questions and arguments
> concluded from my results below still stand regardless
> of whether I use the unradiated or radiated ep-elastic
> generator with or without resolutions inserted. My
> arguments for these beliefs are as follows:
>
> a) Inserting resolutions merely smears the output of
> Monte Carlo. It does not shift the peak. Using
> the proper functions to analyze the Monte Carlo
> output, any problems will be much more readily
> apparent before inserted resolutions.
>
> b) "Radiated" MonteCarlo affects the electrons and
> only less than 40% of the time. The affected
> electrons will have less energy and thus create a
> tail. Again, the "radiated" tail will not shift
> the peak. When I plotted the "UNradiated" Monte
> Carlo output in a histogram describing the elec's
> momentum vs. theta, I got a line. When I plotted
> the "Radiated" MC output on top of this, I got the
> SAME line with some (~20%) scattered points
> beneath the UNradiated curve.
>
> c) According to Aaron:
> http://blast.lns.mit.edu/BlastTalk/archive/5211.html
As far as I know, no one has incorporated Aaron's energy loss
corrections into their analysis.
It seems to me that it should either go into the final stages of the
reconstruction code, or easier,
into the analysis scripts for the various channels, but not into MC.
> a monte carlo model of momentum lost by protons
> and deuterons had been analyzed. I, yet, am still
> waiting to here if this is finalized and actually
> in the present MonteCarlo for ep-elastic. My
> guess, after looking at the results here, is that
> if it is included, it is in dgen for the deuteron
> reactions.
>
> d) A hypothesis that I make based on my observations
> of the MonteCarlo data is that the ep generator
> generates the electron's kinematics based on the
> ep-elastic cross-section and then, from the
> electron's kinematics, calculates the expected
> proton's kinematics. I don't find any indication
> that each particle is unique, nor that they are
> reconstructed separately. I would love for
> someone to describe to me what happens in the
> reconstruction when I invoke the '-m' flag for
> lrn.
>
> e) KINE and other Flags in fort.99:
>
> KINE 10 1. 1. 0. 45. 0. 21. 0. 11.
>
> ANNI 0
> BREM 0
> COMP 0
> DCAY 0
> DRAY 0
> HADR 1
> LABS 0
> LOSS 1
> MULS 1
> MUNU 0
> PAIR 0
> PFIS 0
> PHOT 0
> RAYL 0
> STRA 0
> SYNC 0
>
>
> Results from plotting ep-elastic kinematic relations
> -----------------------------------------------------
>
> 1: There are negligible differences in both the electron's
> theta and momenta relations, e.g.
> [ theta_e(meas) - theta_e(p_e) vs. theta_e(meas) ]
> and the analogous proton's theta and momenta relations.
> They are included as Electrons.gif and Protons.gif. The
> fact that there are two identical histograms shows no
> sector dependence. Momentum differences in this
> "measured - calculated" amount to almost 1 MeV in the
> electron (note: the y-axis in this plot is multiplied by 10^-1)
> and 3 MeV in the Proton. Theta differences in
> proton reach up to 1 thousandth while electron theta
> differences show 2 thousandths. Negligible.
>
> 2. Beam Energy reconstructed from particles is in
> BeamEnergy.ps. Beam Energy calculated from the electron
> and then in the second histogram from the proton show
> values from 850.5 MeV to 853 MeV for the electron over
> theta_e and from 850 to 856 MeV for the electron over
> theta_p. For these, I do not understand how both of
> these land above 850 MeV. If Proton Energy Loss is in
> this Monte Carlo, how can I get values at or above 850
> MeV for calculations from the proton?
>
>
> Further Studies Currently Under Way
> --------------------------------------------
>
> 1. Regenerating Radiated and Unradiated ep-elastic
> MC files on the Buds rather than the ASU computer,
> just in case I have an architectural difference that is
> affecting the software. I had strange errors in the
> config.sub file and the Makefile for DGen that aren't
> present on the blast machines when I do a cvs checkout.
> This may have affected the results, but I needed to
> explore the ins and outs of the MC visually before I
> started running batch jobs on the buds. The INFO
> attached to the necessary files are informative but the
> nuances still require a bit of experimentation and I'm
> still not confident with the MonteCarlo... even though I'd
> like to know who is.
> If someone can give me guidance as to how I can
> generate files with a different name than event.coda
> and how I might be able to "lrn -m event.coda" to
> different filenames than flr-0.root, lr-0.root and
> dst-0.root, the process would go much much faster.
> 2. I will insert resolutions and recreate same analysis with
> radiated MonteCarlo.
> 3. Anything else that is requested as a result of this email.
>
> -eugene
>
>
>
>
>
>
> -----------------------------------------------------------
> Eugene Geis
> PhD Student, Physics Department, ASU
> Research Affiliate, MIT-Bates Laboratory of Nuclear Science
> eugene.geis@asu.edu
> -----------------------------------------------------------
> <BeamEnergy.ps>
> <Electrons.gif>
> <Protons.gif>
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