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Abstract |
The LHCb is starting to take data in Run 3 with a completely renewed
DAQ system. One novel opportunity offered by this system is triggering
on long-lived particles at the very first stage of the trigger, running at the
full LHC crossing rate of 30 MHz. Moving the selection of V0’s from the
second LHCb trigger level (HLT2) to the first (HLT1) is expected to increase
trigger efficiency significantly. This is confirmed by a detailed simulation and
optimization study, performed on trigger selections based on the presence
of either one, or two Ks. Using as benchmarks some specific channels of
interest with Ks particles in the final state, like D0-¿KsKs B0-¿KsKs, we
obtain large predicted increases in selection efficiency, up to 2.6x for the D0-
¿KsKs channel, at the price of a very modest increase of HLT1 computational
load and trigger rate.
We therefore proceeded to implement these selections in the GPU-based
HLT1 trigger sequence, and acquired data during the physics data-taking
LHCb run in year 2022.
In this talk, we present the results obtained from the first data collected
with this unique trigger, yielding good quality Ks and Ks-pair samples even
from a very limited integrated luminosity.
We conclude with a discussion of the physics prospects opened by this new
trigger, and its planned extension to tracks decaying outside the volume of
the VELO subdector (”downstream tracks”), that will further increase its
acceptance for LLP
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