Squark decay signal:

Dec_2015 Santiago: HT Predictions with Full Data Set

I recreated the HT prediction plots from January, this time with the full data set. The full set of plots can be found here Final_HT_predictions.tar.gz.

Aug_12_2015 Santiago: Recreating Fake Rate Plots

Plots of the probability of a qcd jet of having > 100, 150 or 200 GeV of mass were made, in the same way as done on Nov_24. The full set of plots can be seen here Aug_12.tar, and a sample below.

Jul_23_2015 Santiago: Final ggNtuple Test Plots

The ggntuple containing the full data was obtained, and a couple of test plots were made. The first plot shows that all the events are present in the ntuple, and the second is a JetPt plot similar to the one in the entry of Oct 24th 2015

Jan_06_2015 Santiago: Estimating HT on events with isolated photon

Following the work from the previous post, the HT estimation was done with the new fake rates. Whole set of plots: Jan_06_HT_predict.tar.gz

Jan_06_2015 Santiago: Adding photon isolation condition

So far we have studied the (fake) rate at which background jets would have a mass greater than a certain value (we tried for 100, 150 and 200 GeVs). In addition to the requirements used so far (cuts in HT and Eta, plus requiring at least two jets with Pt > 50 GeV) we want to find the effect that requiring at least one loosely isolated photon with Pt > 30 GeV would have on these fake rates. Isolation conditions can be found here https://twiki.cern.ch/twiki/bin/viewauth/CMS/CutBasedPhotonID2012

First, we check that these rates are similar for samples with 2, 3 or 4 jets. Jan_06_fake_rates.tar.gz

Dec_30_2014 Santiago: MC HT plots

The conditions imposed for the plots in the HT prediction plots were aplied to the MC sample (T2_1000_150), to explore the HT distributions.

Dec_23_2014 Santiago: HT predictions V3

After a couple of bug fixes, the HT predictions finally look OK Dec_23.tar.gz.

Dec_18_2014 Santiago: HT predictions V2

I found a mistake on the code used to make the plots of Dec 15. This caused only the individual jets with low tau ratio to be excluded, rather than the whole event. Here ( Dec_18.tar.gz) are the correct plots, as well as the individual HT plots of data and estimation for each sample.

Dec_15_2014 Santiago: HT predictions

Using the probabilities mentioned in the previous post, the HT of events with exclusively zero one jets, exclusively one jet, etc. were calculated, and then compared to the actual histograms of said events. This was done for samples of events with 2 jets and events with 3 jets. This plots can be found here Dec_15.tar.gz. Here are two examples for the 2 and 3 jet sample respectively:

Nov_24_2014 Santiago: Low Tau Ratio Events Dropped; Edit Dec_03

Since we observed that the events with extremely low tau3/tau1 ratio were localized in a very narrow space in eta and phi, we conclude that these events are product of a misreading of some sort, and we simply discard all events with tau3/tau1 < 0.03 .

Also, the probability of 1 background (as defined before) jet having mass > 100 GeV was plotted according to the Pt, and and pseudorapidity of the jet. This was done for events with 2, 3 and 4 jets, to make sure these three follow a similar pattern. They can all be seen in the following plots:

Note: A bug in the code that affected previous versions of these probability plots was fixed.

Edit: The same plots for jet mass > 150 GeV and 200 GeV have been uploaded here Dec_03.tar.gz.

Nov_18_2014 Santiago: More (Corrected) low tau3/tau1 ratio plots

Nov__18.tar.gz

On the TauRatio vs JetMass plots uploaded on Oct 31st we noted a few events with notably low Tau3/Tau1 ratio. A few plots were made for this low TauRatio area to explore the properties of these jets (plus we wanted to know if these events are the same that show up as a line in the jetPtvsMass plots of Nov 5th, and in fact these jets seem to line up similarly):

Conditions and Cuts

• lowTauRatioJets: Tau3/Tau1 < 0.03; jetPrunnedMass > 200 GeV
• suspiciousArea_inJetPtvsNconst: Jetnconstituents < 60 (no pt cut applied this time)

Note also the unusual eta and phi distributions of jets in this area.
Another suspicious area was observed in a previos uplot of jetPt vs nConstituents of the jet, and some plots of this area were made as well (and named witht he prefix "suspiciousArea_inJetPtvsNconst_*"). Finally, we are interested on knowing the function that describes the probability of a background jet having a mass of 250 GeV with various conditions for the background sample: 2 jets with Pt > 50, and number of jets == 2, 3, 2 or 3 (these 3 cases separately).

**In this plot the x axis depicts Jet Pt while the y axis shows the probability

Nov_05_2014 Santiago: Background Plots of Jet Pt vs Mass. Curiously low tau3/tau1 ratio

Although the ggntuples of the HT datasets is not complete yet, I've generated a new set of plots. Here are two depictions of the jet's transverse momentum vs the jet's mass, one before the tau3/tau1 < 0.35 cut, the other after.

Also, from the plots on the post of Oct 31, we observed that there are some events with a very low tau3/tau1 ratio. The pt distribution for these jets, among other plots can be found here Nov_05.tar.gz.

Oct_31_2014 Santiago: Background vs Signal Jets

We define our signal by requiring events with 4 or more jets, of which at least two have to have mass greater than 50 GeVs. With this criteria we separated the events into background and signal events, and obtained this set of plots Oct31.tar.gz.

*Here, a single HT cut > 900 was used

Note:

The HT datasets we will use are the following:

/HT/Run2012A-22Jan2013-v1/AOD
/JetHT/Run2012B-22Jan2013-v1/AOD
/JetHT/Run2012C-22Jan2013-v1/AOD
/JetHT/Run2012D-22Jan2013-v1/AOD

These first few plots, though, were made only with the ntuple from the first dataset.

Oct_24_2014 Santiago: More Test HT plots

A series of plots were obtained from the HT dataset ( /HT/Run2012A-22Jan2013-v1/AOD ). Even though this doesn't represent all the data we will take into account, this code will be suitable to obtain the plots from the full ntuple. Here are some of the notable plots obtained, the full set can be found here Oct_24.tar.gz.

Oct_13_2014 Santiago: First HT plots

Although the process of ggNtuplizing is not 100% finished, I have made a few preliminary plots using only some of the files. This I made for a few reasons: have the code ready to run over the final ntuples when they're ready, get a sense of how long this code will take to run, and start trying out some ideas of plots just to see what we get. Here are the first few plots I obtained from this reduced test HT ntuple:

Titles and beautification of this one are still in progress, in the meantime the ugly plot:

Oct_06_2014 Santiago: Summary of Gen File Production

For the past few weeks I've been busy with the generation of files I will need for the analysis. The most time consuming was the production of AODSIM files. For this part, the final resulting file production is being documented in this spreadsheet.

Appart from the AOD generation, I also worked on obtaining ggNtuples of HT datasets. Many tests were performed, and many issues were encountered in the way.

Some templates of the configurations I used can be found here, together with a brief description of the problems I ran into and how we managed to overcome them. (to be continued)

Aug_29_2014 Santiago: Jet Matching (neutralino jets)

To find the jets that correspond to the singlet decay products I did the following. First, for each jet I found the closest two gluons from a singlet and plotted this to find a threshold for delta R. Then, depending if one or two gluons met the delta R requirement the jets were classified as G jets or GG jets (the plots made today correspond only to the GG jets). The complete set of plots can be found here Aug29.tar.gz .

Aug_28_2014 Santiago: Jet Matching (quark jets)

EDIT: These plots were remade with more rigorous parameters see these on the entry of Aug 29

NOTE: From now on, when I say quark I mean quark from a squark unless otherwise specified.

To characterize jets as quark jets (jets from quarks that come from a squark) and neutralino jets (the fat jets that come after the neutralino decay) I computed Delta R between each quark and all the jets in each event, and stored the minimum value. Then using this minimum Delta R plot we can impose a requirement on Delta R to classify a jet a quark jet. I found this value to be 0.6

These ( QuarkJet.tar.gz) plots were obtained from the selection

Aug_25_2014 Santiago: Jet Mass/Energy vs Tau/Tau Ratio

Plots of jet mass and energy versus tau3 and the ratio tau3/tau1 (all combinations) were made to find if there is any correlation between these variables that would permit a separation of the of the interesting events of the signal.

Aug_20_2014 Santiago: Jet Energy vs Mass Plots

The plots of energy vs mass were made. I was curious to see the difference would be if we consider the total energy instead of the transverse energy, and also what would change by the use of the jet mass instead of the pruned jet mass. The combinations of these are shown here:

Aug_18_2014 Santiago: Selection Based on Number of Isolated Photons

The cases where exactly zero, exactly one and either zero or one photons met the isolation conditions were separated. Some of the plots presented earlier were redone implementing this separation. All the plots can be found in this nIsolatedPhoCuts.tar.gz. Some examples are shown below:

These plots show a similar plot as the one uploaded on Aug 15, but in this case it's separated for cases where zero photons meet the isolation conditions, one photon meets these conditions, or either one or two photons meet the conditions.

Aug_15_2014 Santiago: Counting Jets

EDIT Aug_19 : - The plot of number of matched photons per event presented just below was not correct. The correct plothas been posted instead.

- The photon isolation conditions were taken from the following study: https://twiki.cern.ch/twiki/bin/viewauth/CMS/CutBasedPhotonID2012#Cuts_optimized_for_non_triggerin

The number of photons per event that pass the Tight, Meduim and Loose conditions are depicted here.

Similarly, the number of jets per event was obtained. Some cuts on the energy and mass (prunned) of said jets were applied as well.

Finally the pruned jet mass histograms were plotted, both before and after tau3/tau1 < 0.35 cut.

Aug_08_2014 Santiago: Photon Match Results

The Pt of all the generated photons and of the generated photons that matched the reconstructed and then compared.

It is also interesting to find out how many of the generated photons were matched per event.

Note that at most only one photon per event.

Aug_07_2014 Santiago: Matching Photons

We are interested in knowing if the reconstructed photons actually match one of the generated photons; furthermore we are interested in determining if these reconstructed photons came from the signal we are interested in, e.g. if they came from a neutralino, as shown in the following diagram.

To do this matching we compare the spatial location of the reconstructed and generated photons by analyzing the differences in eta and phi for each one (magnitudes named DeltaEta and DeltaPhi).

From these we impose the conditions that DeltaPhi < 0.04 and DeltaEta < 0.04.

With this cuts, we can search which reconstructed photons fall within this deltas and do the matching.

Aug_06_2014 Santiago: More plots from the ggNtuple

I continued exploring and playing around with the ggNtuple using MakeClass (). I was interested on seeing the differences between the Pt plots of the generated photons and the reconstructed photons. This is the result

-- SantiagoRafaelParedesSaenz - 06 Aug 2014

Aug_04_2014 Santiago: First plots form the ggNtuple_T2_1000_150

Using the T2_1000_150 ggNtuple located at ' /eos/uscms/store/user/ecarrera/ssusy/ggntuples/pythia8/T2_1000_150/ggtree_T2_1000_150.root', I plotted the Pt, Eta and Phi distributions for the photons, gluons and quarks for the generated events. Here are some of them (the rest can be found here Plots_T2_1000_150.tar.gz):

Aug_01_2014 Santiago: Creating TWiki pages for the project

I created two TWiki pages for the Stealth SUSY analysis. This is one of them, which will serve as a logbook to document the process, and another one located here where we will store relevant information.

-- SantiagoRafaelParedesSaenz - 01 Aug 2014

July_30_2014 Santiago: Getting familiar with Ntuples

To become more familiar with the Ntuples (and as a quick reminder of the works of ROOT) I created some simple plots from a Ntuple.

In the Ntuple, each event can have an indeterminate number of jets. What I've done this time is separately plot the Pt distributions of the least energetic jet for events with 2, 3, 4 and 5 or more jets. Here the first case is shown

(/uscms_data/d3/sparedes/stealthSUSY/Ntuplizer_538v1/src/SusyAnalysis/SusyNtuplizer/macro)