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Academia Sinica group meeting
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Shahzhad
Starting today start the HGTD October test beam shifts, which will last a week.
This week attended ATLAS induction week, lectures on ROOT, includes PyROOT, SWAN environment, parallelism, (ROOT is modified for that as well). R data framework declarative framework. There is now a GitLab about ROOT, with instructions, and a place to ask questions to experts.
Rachid
He is in Rabat, Marocco, for a week, to work with two PhD students from there that will join our group.
1. He finished qualification on TRT so started on VBF H->inv for full Run-2 data
2. She will finish the qualification task in Dec and started to look at dark photon production at the LHC, later she could contribute to HGTD as well.
Working on the dark photon search with a theorist, trying to find a connection between the Higgs and a dark photon sector (Higgs portal). ATLAS did not do it yet. CMS did it in Run-1 in a simple way. There is something to investigate, it is new to look at low mass (usually searches are done at high mass). Instead of H->2gamma you have H->gamma + dark photon (extra coupling in ttbar loop for gamma-gamma; but because BR limit is large enough you can insert a DM mediator that couples to dark photons; mostly the same diagram giving you a photon (low pT) and dark photon (low, so low MET). The theorists propose an inclusive search, but impossible due to pileup, trigger (hard at low pT). You can have same signature just from combination of badly combination of jet energy (jets + MET + photon). So then started with ZH, with Z->ll and Higgs -> photon + dark photon (MET), as it is cleaner. The goal is to check the sensitivity we can reach. Later we can check also the VBF production mode.
Adrian
One talk on PtReco b-jet energy corrrection in three cases of muon-in-jet correction. Accounting for grey muon changes the shape of the correction, increases the correction factors. Currently implementing this in analysis to compare the mbb shapes after the full selection for the two types of PtReco.
Another talk on comparing the old and the new derivations for VHbb in all three channels, in all categories of low, high pTV. Last week showed that the derivations and CxAOD have the same number of events. Now the histograms from the Reader show an increase in yield, and furthermore a change of shape, with yield increasing more at high pT. Both of these are not expected and must be understood, but are consistent with observations from other analysers last week.
Adrian reported also on other updates of the CP calibrations that are ongoing this week: storing isolation working points for electrons and muons, adding electron trigger, reducing the number of CoM jets that are stored, and for each jet the number of b-tagging working points that are stored.
Wei
Adrian reported on behalf of Wei that MET trigger was updated for 2018 data to be added to the CxAOD and that the Jet Jvt calibration has been added to the CxAOD.
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