[Eic-core-phys] simulation goals and beam energies

[Pawel Nadel-Turonski]

Sorry, there was a typo. :)
I of course meant to say that maximum energy is most important for gluon saturation and delta G!

Cheers,

Pawel

On Sep 24, 2021, at 9:46 AM, Pawel Nadel-Turonski <turonski at jlab.org<mailto:turonski at jlab.org>> wrote:

Hello Everyone,

It looks like the simulations are now making quick progress!

In this email I just wanted to follow up on the brief discussion we had on proton beam energies at the last meeting, and the overall simulations goals as outlined in the call for proposals.

Starting with the latter, the call
https://www.bnl.gov/eic/CFC.php
states that
"A description of the science addressed and performance estimated through simulation including, but not limited to, e/γ, jets, π/K/p separation, vertex, and tracking, and how the simulated performance compares to the requirements detailed in the YR.”
The tracking and vertex requirements will be addressed through F4A simulations. Electron and photon detection are a key capability of CORE, and we would want to highlight this in the simulations (electron purity, DVCS on nuclei, etc). We would also need to highlight the hadron ID. Of course, we should also show other relevant simulations, but addressing the text in the call for proposals is probably a good strategy!

Which leads me to the proton energies. During the meeting I suggested the following:
18x275: max energy, low luminosity
10x275: max luminosity
5x275: max luminosity, best PID
5x100 medium luminosity
5x41: low luminosity, beam qualify may be questionable for exclusive measurements

The maximum luminosity setting is important for gluon saturation (with heavy ions), delta G, and some jet physics, but while we may want to simulate it in some context, it is probably not the setting we want to use for most simulations.

The 10x275 and 5x275 settings give the highest luminosity - but the 5x275 one has a more favorable distribution in terms of hadron momenta - with high momenta in the hadron endcap (where we have a dual-radiator RICH capable of doing pi/K separation up to 50 GeV) and lower momenta in the electron endcap. From this point of view, unless the higher energy would be important, the 5x275 setting may be a better baseline.

The 5x100 setting has about a factor 3 lower luminosity than the 5x275 one. The main advantage is that it allows reaching the same point in the x-Q2 plane at a higher value of y when compared with 5x275 (since Q2 = s y x).

The 5x41 setting is like the previous one, only with even lower luminosity and access to even higher y for a given x and Q2.

Other settings are also possible if you would find the need for a different configuration, but these are probably a good start.

Cheers,

Pawel



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