Missing Et Before and After Shutdown

Yuri Gershtein

7/8/2003 Yuri Gershtein - CALO Meeting 2

The Problem Di-EM skim:

2 EM objects Et>7 GeV ~3% of the data

MET in gg events with all clean-up cuts except H-matrix (i.e. signal + background together)

Tails are obviously worse in the post-shutdown data – WHY?

Run < 172K

Run > 172K

7/8/2003 Yuri Gershtein - CALO Meeting 3

Bad runs? Hypothesis: may be the looser selection criteria for post-shutdown data make a difference?

run

Fraction of events with MET>20 GeV

What happened after run 175500?

all events from diEM skim

Moriond Sample

I II III

7/8/2003 Yuri Gershtein - CALO Meeting 4

Bad runs?

run

Fraction of events with MET>20 GeV

Good runs from diEM skim

Bad runs from diEM skim

7/8/2003 Yuri Gershtein - CALO Meeting 5

Two hot regions

All events

MET > 20 GeV

All events

MET > 20 GeV

MET Azimuth MET Azimuth

jets

EM objects

II III

7/8/2003 Yuri Gershtein - CALO Meeting 6

End of Story?

All events Good runs Two hot spots removed

Both hot zones are not present after my cleanup cuts – only CC em’s and no jets in ICD region

MET

7/8/2003 Yuri Gershtein - CALO Meeting 7

MET before – after shutdown

MET

Normalized at MET<20 GeV

x2 difference at MET>40

x5 difference at MET>120

7/8/2003 Yuri Gershtein - CALO Meeting 8

MET v.s. MET Azimuth

MET

MET azimuth

MET azimuth

MET > 30 GeV

MET > 50 GeV

MET > 100 GeV

III

7/8/2003 Yuri Gershtein - CALO Meeting 9

Event from the peak

The event has two isolated EM objects – simple cone clustering…

7/8/2003 Yuri Gershtein - CALO Meeting 10

Run dependence? MET azimuth v.s. run for MET > 30, 50 and 100 GeV 162K <run< 172K – clean run < 162 K – worse run > 172 K – a mess…

7/8/2003 Yuri Gershtein - CALO Meeting 11

Zoomed For Run > 172KAlmost all data is

affectedWorst for run > 176184

(Apr 26, after a 4 day shutdown…)

7/8/2003 Yuri Gershtein - CALO Meeting 12

Look for more hot regionsEM objects, Et > 20 GeVRun range I (run < 162 K) good runs

detector eta

azimuth

7/8/2003 Yuri Gershtein - CALO Meeting 13

Look for more hot regionsEM objects, Et > 20 GeVRun range II

(162K < run < 172 K)Good runs

All events

MET > 30

MET > 30, HM > 50

7/8/2003 Yuri Gershtein - CALO Meeting 14

Look for more hot regionsEM objects, Et > 20 GeVRun range III (run > 172 K)Good runs, hot spots removed

All events

MET > 20

MET > 20, HM > 50

More than ten hot areas!!

7/8/2003 Yuri Gershtein - CALO Meeting 15

Hot EM regions It seems that there is always some energy in these hot areas:

no good EM particles in these areas…

HMatrix Chi2 HMatrix Chi2

Hot EM

Normal EM (same eta)

Hot EM

Normal EM (same eta)

7/8/2003 Yuri Gershtein - CALO Meeting 16

Hadronic Hot Regions Run <162 K, good runs, leading jet, MET>30

7/8/2003 Yuri Gershtein - CALO Meeting 17

Hadronic Hot Regions 162< run<172 K, good runs, leading jet

MET > 30

MET > 50

7/8/2003 Yuri Gershtein - CALO Meeting 18

Hadronic Hot Regions run>172 K, good runs, leading jet, MET>50

7/8/2003 Yuri Gershtein - CALO Meeting 19

Summary (1)

Need better monitoring of the calorimeter The typical failure mode in the data is a hot cell/tower/BLS/ADC/… which is

fires at a relatively small rate invisible in distributions like jet eta-phi for all

events, need monitoring for events with large MET

persistent through a long period of time have relatively small energies, from 30-40 GeV to very small…

7/8/2003 Yuri Gershtein - CALO Meeting 20

Summary (2) Is the data recoverable? Almost all post-shutdown data is affected Possible ways to recover

may be the hardware signature can be recognized (similar to the BLS recovery)? may be the cells (if these are cells!!) should be excluded from MET calculation? may be just reject events with energy in the hot areas? – easiest to do, hardest to calculate efficiency of – plus, there are A LOT of hot areas