Changes for IFT SMOG2 2024 re-sprucing
This MR collects the changes to the IFT sprucing lines for the 2024 re-sprucing campaign.
The changes include:
- Testing of isolated photon sprucing lines on nominal pp data. The corresponding HLT2 lines were merged in August 2024, and the sprucing lines were added in the pp reference run MR (!3749 (merged)) but had not yet been tested on nominal pp data to see if an additional prescale was needed
- Photon container is persisted in the Ds+ line for reconstruction of excited Ds+ states
- Proton containers are persisted for charm correlation studies (D0-Lambdac etc)
- Loosen some minimum bias prescales
Bandwidth tests performed:
- On 2024 pp data with mu = 5.2 (the official EoY sprucing test samples). Running over 371007 real data events, the total bandwidth due to the isolated photon sprucing lines was found to be 0.002 GB/s. The HLT2 lines already have prescales, and since the bandwidth used by these lines is extremely low, no additional prescales are applied in the sprucing lines.
- On 2024 pp data with simultaneous SMOG2 He injection (from /eos/lhcb/wg/rta/WP3/bandwidth_division/COLLISION24-run301222/hlt2/hlt1_pp_matching_no_ut_1200KHz). Running over 28,543 events, the total bandwidth due to the IFT lines is found to be 0.0023 GB/s
- On 2024 pp data with simultaneous SMOG2 Ar injection (from /eos/lhcb/wg/dpa/wp1/data/EoY-spruce-2024/304231_00140000_0040.raw). Running over 63,174 events, the total bandwidth due to the IFT lines is found to be 0.012 GB/s.
Note that each gas injected has a different pressure set point, some of which are higher than others. For example, pH has a rate of around 3x that of pHe (link).
Total bandwidth estimate:
Our total bandwidth estimate is the sum of the lines that run on pp data (0.002 GB/s on mu=5.2 pp data) and the sum of the lines that fire on SMOG2 events when SMOG2 gas is injected (ranges from 0.0023 - 0.012 GB/s depending on which gas is injected).
For fills without SMOG: 0.002 GB/s
For fills with SMOG: 0.0043 - 0.014 GB/s (depending on the gas injected. Lower value = Helium, Upper value = Argon)
Bandwidth change: doubles the current IFT sprucing bandwidth, but the total bandwidth is still very small
This is also a conservative estimate for the following reasons:
- We did not inject SMOG during every fill
- For the fills in which we did inject SMOG2, the gas pressure decreases over time, so the rates also decrease as a function of time
- In the above estimates, the bandwidth for the lines that run on pp data is obtained from testing on mu=5.2 pp data, which does not correspond to the mu for most of the data taken this year.