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2023 LHC DM WG Spring Meeting
Description
Plenary meeting of the LHC Dark Matter Working Group.
Useful links:
Videoconference
LHC DM WG workshop
- Zoom Meeting ID
- 68024266716
- Host
- Oleg Brandt
- Alternative hosts
- James Frost, Spyros Argyropoulos
- Useful links
- Join via phone
- Zoom URL
-
Luca
———
what is the time scale for the white paper?
=> wanted to have a first version of all sections by the summer.
=> Bottlenecks: doing RECAST takes time and many theorists do not have access to clusters. If anything can be provided from the experimental side, .e.g running simulations etc would help to speed up the process
=> Section on benchmarks will need to be discussed in coordination between theorists and experimentalists
if experimental input is needed we can encourage more people to connect to the next general t-channel meeting when a date is fixed
Changqiao
—————
p6: how do the 2 selections work?
=> For each events above pT(TAR jet) > 300 GeV first the merged selection is checked. If the selection fails then the resolved selection is checked
p11 the RD line is different than p14
=> the correct line including all effects is shown on p14
p18: Moving to the relic density focused region on page 17, gives us high mZ' and high mchi. But probably we lose any interplay between signatures, or sensitivity at high ms. Is there a way to maintain some of the latter?
Hassnae
——————
p15: the lowest dark photon mass for which we set a limit is at 5 GeV. This is because of the trigger?
=> Yes
Elisa
———
Has the trigger strategy been updated to extend the searches to low m(mumu)?
=> The scouting trigger approach is the same. Some optimisation was needed for the low mass region, e.g. wrt the muon identification but on the trigger side the strategy was the same
p15 selection has pT > 4 GeV but m(mumu) goes down to 1 GeV. You are working on the trigger turn on?
-> Yes
How is the model-independent limit derived. You split up the spectrum in m(mumu) with a width that is similar to the experimental m(mumu) resolution?
-> Signal injected in bins that have a width of 5x the m(mumu) resolution ~1.5%
p16 any particular reason why you choose sintheta=1? This should be probably completely excluded?
=> sintheta=1 was chosen for the plot on p16 but limits are also provided as a functions of sintheta and tanb (p17)
Blaise
———
are there any plans for specific studies where the excess is at m(mumu) ~ 2 GeV?
=> no
p13 in the bottom plot there is a step at ~ 1 mm. Is this due to detector or due to the model?
=> probably has to do with the model
How will the fully software based trigger affect the analysis?
=> The hardware level trigger imposes some constraints on the kinematics. The software trigger will allow to go to softer muons.
For Run-2 the pT threshold is 1 GeV. Not clear exactly how low one can go with the software trigger.
Hugues
————
p5 how was the limit improved from 5% to 0.4%?
=> Old papers were very conservative and using old experimental results (2014) with some experimental results which were not public so they made some very conservative estimates of what the experimental sensitivity would be
What is the leading contribution of the improvement?
=> It’s a combination of the new data and using new constraints e.g. from oblique parameters that were not considered
Is there any other method to search for massless dark photon at the LHC?
=> currently working on h->Z+dark photon but it’s more difficult to observe
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