General MWG Meeting Summary 5/11/20

PARTICIPANTS: Carlos Ayerbe, Tanja Horn, Richard Trotta, Arun Tadepalli, Stephen Kay, Rolf Ent, Yulia Furletova, Dmitry Romanov, Tim Hobbs, Garth Huber, Tobias Frederico

EVENT GENERATOR (Richard)

• Discussion 18 on 275 with y-cut=(0.01, 0.95)

• to reach the large x region at a certain Q^2, the lowest possible energy is normally best. For high beam energies this area requires y to be low.

• Discussion of 10 on 100, 5 on 100, and 5 on 41 kinematics with same y-cut

• for 5 on 41 and 5 on 100 can access more acceptance at high-x, but lose acceptance to the low-x region, for 5 on 41 even more
• Looks like best energy seems 10 on 100 or 10 on 135
• But consider that for 5 on 41 might have advantages for the Lambda detection

• Generator doesn't have kaon model yet, but could be done straightforward - already have some code for that

• Action Items:

• evaluate statistical uncertainty, especially at large x (linear plot)

• fold in detection efficiency
• include detector smearing

• Update labeling: really showing t', which depends on Q2 (measure of how close can get to the pole)
• Add one lower Q2 bin, e.g. 2.5 or 3.25 GeV2
• Run 5 on 41 with more statistics
• Make pion-neutron MC samples of all energy combinations for Geant4 detector analysis - good to see how detection efficiency (neutron detection fraction) changes with energies
• Make a kaon plot for Pavia meeting?

FIRST LOOK AT LAMBDAS IN FF (Yulia, Dmitry)

• Presentation of Sullivan process with Lambda detection in far forward (first look, real detector sizes, e.g. RP, yet to be implemented)

• electron in central region - missing band in Q2/xBj seems due to low statistics
• Decay channels: Lambda -> p + pi-, Lambda -> n + pi0
• Illustration of Lambdas decaying in different places between central detector and ZDC
• Kinematic distributions of proton and neutron

• Decay Length (p/n vertex)

• decay lengths at different energies
• For kaon cannot afford Lambda to have too long decay length -> seems to point to lower energies 41 GeV, 100 GeV
• For 5 on 41 even get many decays in central detector - but issue perhaps that cannot get pi-, maybe can detect in central detector endcap somehow?
• At high energies also have 1/3 lambda do not decay

• Virtual plane after dipole configurations (after B1) to evaluate occupancy/cone in different sub detectors

• Next: include inefficiencies with real detectors - size of Roman pots

• Lambda -> proton + pi-

• Collider: Lambda decays many meters away from vertex and products can go anywhere
• How to figure out momentum at vertex of decaying particles, e.g. proton? - for DVCS have correlation since assumed in primary bunch, then can reconstruct

• Lambda -> neutron + pi0 looks doable, but need to check pi0->gamma gamma (could get from EM part)

• Here have energy of neutron from ZDC
• At front of ZDC: two spots, one for pi0 and one for EM
• For reconstruction of gammas --> need a tracker before ZDC to veto and measure tracks from pi-

• Maybe use GEM or Si-based tracker

• Need good EM part (PbWO4 or similar) and probably high granularity

• Action items:

• include inefficiencies with real detectors
• Decay lengths at different energies
• Distribution of photon distribution from pi0 decay

PAVIA MEETING

• Request one presentation of 20-30 minutes, speaker: Richard

• Prepare a rough outline of the talk by 12 May

• Specify plots needed before weekend

• Final dry run Monday May 18 at 4pm

FROM MINUTES OF THE EIC FORWARD DETECTOR/INTEGRATION GROUP MEETING:

First look on Lambdas in FF region: Yulia Furletova

• Lambdas provide a path towards Pion/Kaon structure functions and would give further progress towards flavor decomposition

• Lambda => p + pi- we get the protons but we need trackers in opposite

direction ( charge) => on the path to ZDC For Lambda => n+ pi0, neutrons could be detected efficiently, but need to check %0 -> )) ( gamma energy and momentum spread)

• Elke asked how we could recontruct momenta? Yulia thought that by putting cuts on the lambda decay volume it may be possible to find the momentum. Tanya commented that we will need the full Lambda 4 vector to get the t distribution. A tracker, or at least a charged particle veto in front of the ZDC may help in tracking pi0.

NEXT MEETING: MONDAY MAY 18 AT 4:00PM (ET)