<MET> / run : Moriond vs Post-Moriond

1
D0 Calorimeter Algorithms Task Force
------------------------------------- Members of
the Task Force Gregorio Bernardi(chair), Jonathan
Hays, Serban Protopopescu, Markus Klute, Jan
Stark, Robert Zitoun, Vishnu Zutshi Charge to
the Task Force The task force will optimize in
collaboration with the Physics and ID-groups the
calorimeter algorithms for precision physics. It
will start from the achievements of the
Calorimeter Task Force, continue to improve the
algorithms and propagate them to the physics
objects using as benchmarks the comparison
data/simulation of the W (-gte nu) transverse
mass spectrum and Jet Met resolutions in di-jet
events. The task force is expected to coordinate
the efforts in the different groups related to
the calorimeter.
2

• Specifically, the task force should
• 1) Make progress on the understanding of the
  calorimeter noise.
• 2) Finalize the development of an optimized
  0-suppression scheme and study
• its consequences for MET, EM, Tau and Jet ID.
• 3) Make progress on the understanding of the EM
  response/resolution, using
• on-line and off-line tools.
• 4) Make progress on the data/mc agreement of the
  calo objects reconstruction
• and of the energy flow algorithm.
• 5) Use large statistics of W and di-jets events
  to display how the
• progress achieved on points 1-4 propagates in
  the corresponding
• physics distributions.
• The task force will report to the physics and
  algorithm coordinators.
• A preliminary status report should be made at the
  Beaune workshop.

3
CAT / CALO meeting

• Calo group has reviewed hardware problems which
  have degraded the response, in particular after
  the shutdown.
• The 2 main problems are now fixed at the hardware
  problem
• In the previous data, the first of these 2
  problem must be searched for by comparing L1 with
  precision readout, and flagged events must be
  rejected (potential bias must be studied).
• The second problem (so-called shared energy
  problem (cf next slide)) can be corrected
  off-line. CAT is providing help to fix it at the
  reco from DST level, such that a p14.03
  reprocessing could still be done for summer.
• A coherent noise problem is still under
  investigation, but it appears at a much lower
  rate ( lt 0.2 of the events)

4
EM - id
Cf task list Influence of noise/t42 on
em-id at low energy (j/psi) at
high energy (Z) Going from the current t42.5 to
t42 -gt em-id
em-response
em-resolution
5
JET - id

• For jet-id (jes is a separate matter), we have a
  set of open points
• (Let's not forget that all these tasks will have
  to be investigated
• for 0.5/0.7 cones, (and 2KT))
• 1) Influence of noise / t42 on jet finding.
• 2) Going from the current t42.5 to t42 -gt jets
• 3) ID criteria with new seeding in p14
• 4) Usage/Certification of track jets.
• 5) Usage/Certification of L1 towers
• 6) Uniformity of jets in eta-phi
• 7) Jet multiplicities
• 8) Problems with jets algos a) splitting
  merging
• b)
  the 0.8-1.5 eta window.
• c)
  Kt algorithm
• 9) jet code responsability

6
tau id / muon id (in calo)

• Suppressing further noise should be helpful for
  taus,
• However since signal is tiny (for muon) the
  effect of T42 must
• be studied carefully, since some signal will be
  removed.
• Possibility run muon finder in calo before t42
  (possibly below 2.5 or 2 sigmas)

7
Jet energy scale / Missing ET / E flow

• JES/ jet resolution cf todays talks
• Missing ET to be treated next time
• CNN/Eflow strongly influenced by the noise.