General MWG Meeting Summary 4/27/20

Participants: Rolf Ent, Julia Furletova, Tim Hobbs, Vladimir Berdnikov, Paul Reimer, Stephen Kay, Thia Keppel, Tanja Horn, Garth Huber, Dmitry Romanov, Richard Trotta

Fixing the bug in the MC (Richard, Julia)

• Recalculated relativistic kinematics for all scattered particles - simulated angle and momentum distributions seem to agree with what is expected now with energy conservation cut

• Beam energy smearing has been implemented, so should accept everything above energy conservation cut - add 5 sigma energy spread to incident energy

• Fixed issue with neutron angular distribution

• neutrons were rotated at an angle and missed the ZDC - fixed now
• note that the angle that was changed is phi, theta is still at ~1.5 deg

* Action items:

• add 5 sigma energy spread to incident energy
• total MC event sample is very large as contains all events (good and bad) - need to implement a way to select only good events
• Weight pion distributions by the cross section
• Run Pion SF events through exclusive pion code for background studies
• Plot pion SF on a linear scale to better highlight the physics at large xpi

K-Lambda Detection (Julia)

• Objective: analyze and optimize detector size needed to capture charged particles
• Analyze cone of Lambda with 275 GeV and Gaussian spread 1-2 GeV

• Lambda decays near second dipole
• Pi- inside 2nd dipole (bend in opposite direction from proton) and missed in the large sensor - need to adjust the size of the sensor

K-Lambda Reconstruction (Dmitry)

• Objective: what resolutions are needed to reconstruct Lambda. General procedure

• Assume perfect detector hits
• Assume particle hits detector and decays if particle hits sensitive volume - these are used for tracking
• Apply granularity, but not there yet - requires fixing the sizes of the tracking detector

• Analyzed Lambda decay - need to determine best way to implement identification of proton and pi-
• Discussion about a second type of Lambda in the MC sample

• in general would expect a smooth decay with a long tail but see a peak and then a distribution
• might be a feature of the MC generator as all events that fail the energy conservation cut are forced to zero

Discussion about neutral pions

• Large fraction hits the ZDC - how to detect and identify?

• Lambda --> proton + pi- (roman pots and track)
• Lambda --> neutron+ pi0 (ZDC - should have enough resolution, but need to pay attention)

• Granularity ZDC

• Two versions currently

Discussion Action Items for Pavia Meeting

• Continue with Action Item list from 4/13

• On May 11 take stock where things are

• new MC samples of ~50k for Geant4 processing
• SF parameterizations - understand theory dependence

NEXT MEETING: MONDAY 11 MAY AT 4PM (ET)