[Halld-klf] [EXTERNAL] two-body kinematics

[Amaryan, Moskov]

hi Beni,

Thanks for your message.
Yes, all the questions you raised need to be answered. One way of doing it would be to use
existing GlueX data and see what happens to the K+ particles depending on their momenta.
Would they have enough momenta after penetrating the target and start counter, would they have
enough energy to deposit sufficient energy in CDC to produce a track and so on.
My student, Tyler Viducic is doing analysis of the K_sK^+\pi^-p final state data and we already looked
at momenta of K+ particles which are minimum at 70 MeV/c or so, but it has to be studied further to see
if we had a single track, how well could we reconstruct K+n final state. The advantage of KLF experiment,
among other things, is the fact that we are going to look not at the invariant mass of K+n, but on W,
the resolution of which is on the order 1-2 MeV at low momenta below 500 MeV/c.

I think we could answer those questions both from data and MC simulations.

The main purpose of the plot I sent out, was to convey a message that in the two-body reaction, the very
forward angles, below say 20 deg, are very small fraction (less than 1%) of the entire phase-space.

Best regards,
Moskov.


 Dr. Moskov Amaryan
Eminent Scholar and Professor of Physics
Old Dominion University
Norfolk, VA 23529​

Phone: 757-683-4614
    Fax: 757-683-3038
________________________________
From: Halld-klf <halld-klf-bounces at jlab.org> on behalf of Beni Zihlmann <zihlmann at jlab.org>
Sent: Tuesday, December 5, 2023 12:33 PM
To: halld-klf at jlab.org <halld-klf at jlab.org>
Subject: Re: [Halld-klf] [EXTERNAL] two-body kinematics


EXTERNAL to ODU: This email is not from an ODU account. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Hi Moskov,

my response to this is the following:
lets take a K+ at 150MeV/c going out at close to 60 degree.
This K+ my need to pass through a substantial amount of liquid hydrogen
depending on where it is generated in the target. This can be between zero
and 7cm. After that it has to pass tough the target cell the scattering chamber
and then through the start counter in order to get to the CDC and produce a track.

so
a) what is the likelihood that a 150MeV/c K+ makes it to the Start counter?
b) how much energy is deposited in the start counter?
c) what is the likelihood that this K+ will generate enough hits in the CDC  to reconstruct a track?
d) There will be only 1 track at best, how can this event be reconstructed with this limited
     since the vertex is not very well defined?

cheers,
Beni


On 12/4/23 17:49, Amaryan, Moskov wrote:
Dear all,

As we discussed today, as an example, please find in the attachment
double plot for the kinematics of K_L+p \to K^+n for 200 MeV/c
of incoming K_L momentum. As one can see, very forward angles
constitute a small fraction of the entire angular range of produced K^+.

Best regards,
Moskov.


 Dr. Moskov Amaryan
Eminent Scholar and Professor of Physics
Old Dominion University
Norfolk, VA 23529​

Phone: 757-683-4614
    Fax: 757-683-3038



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