This uses the same method as before (counting clusters, e+, e-, mu+, and mu-, taking the best bins).  This time, I’ve added in the charge correlation of leptons and clusters: one cluster with an opposite-signed soft lepton inside goes in the ‘qCorr = -1’ bin, a cluster with two opposite-sign leptons (e.g. a cluster consisting of only an e+ and a mu-) goes in the -2 bin, etc.

Continue reading More sophisticated statistics for surgical cuts →

Below are 3 correlation matrices for track/pi0 cluster variables.  The matrices are formed from

1. The signal sample.
2. The W+jets sample.
3. The difference between the signal and W+jets correlation matrices.

Notice that the signal sample matrix is more anti-correlated across all variables than the W+jets sample.  All variables exhibit |rho|>10% for all combinations, i.e. there are no highly uncorrelated pairs of variables.

–Dan

Yesterday, I posted a plot of SNR vs. Signal Events for the three cut sets.  Cut Set 1 was clearly the best of those three, so I added Dan’s nLive cut to that one.  I also removed the requirement that the event have at least one cluster, and ended up with a pretty good S/B in some of the 0-cluster, multi-lepton bins. Continue reading Counting clusters, e’s and mu’s (with nLive cut included) →

I have implemented a cut set based on this one except with the additional requirements that the event contains a soft electron and that the charge correlation for clusters containing an electron be negative. The requirements are as follows:

• met>20 GeV
• ht>100 GeV
• at least 1 soft electron
• at least 1 track/pi0 cluster with pT>10 GeV and N(live)<7.
• if the soft electron is inside a cluster, qCorr<0.

The expected signal and background for these cuts are

I have also made tables of N(live), N(tracks), N(pi0s) for the following cases:

• Event contains a soft electron but it is not inside the cluster. Table is here.
• Event contains a soft electron and it is inside the cluster; no cut on the charge correlation. Table is here.
• Event contains a soft electron and it is inside the cluster and qCorr<0. Table is here.

The 5 most significant N(live), N(tracks), N(pi0s) bins for the 3 cases are listed below.

Soft Electron Outside Cluster

Soft Electron Inside Cluster; no cut on qCorr

Soft Electron Inside Cluster; qCorr<0

Notice that in all of the cases, the most significant bins are with N(live)<4. Also notice that the cut on charge correlation cuts 29% and 44% of the background in the (2,2,0) and (2,2,1) bins, respectively, while barely taking any signal away at all. This is intuitive in the 2 track bin, since one of the tracks must be the soft electron and therefore the other one is a 1-prong tau decay. Since the taus are coming from a neutral a0, the 2 track bin is the most pure for this cut. --Dan

I ran a job to count the number of clusters, soft electrons, and soft muons in the MC samples.  I split up the e’s and mu’s by charge.  I then added up all of the bins with S/B above a particular threshold. Continue reading Surgical cuts on clusters, e’s, and mu’s →

Here is a table that breaks down the number of signal and background events w.r.t. N(live), N(tracks), and N(pi0s). N(live) is as defined before. N(tracks) and N(pi0s) are the tracks and pi0s in a given cluster with the given N(live). The most signal-like bins are:

Notice that the most “signal-like” entries are in N(live)=2 and N(live)=3.

I want to do 2 more things with this table:

1. Change the counting of N(tracks) to count the soft tracks in the cluster cone that do not pass threshold. I did a similar thing earlier when calculating N(live).
2. Require the presence of a soft electron inside the cluster and recalculate the table. I expect clusters containing a soft electron to be more signal-like. We might be able to get further separation for those SE-tagged clusters by looking at N(live), N(track), N(pi0).

–Dan

I’ve started to look at soft muons in the MC samples that we have.  For now, I’m only looking at generator-level soft muons.  I’ve put in a Pt cut of 1 < Pt(Muon) < 20. Continue reading Adding Soft Muons (Preliminary) →

I implemented a cut set similar to Cut Set 1, shown here .

The cuts are as follows:

• tight central lepton pT>20 GeV
• Raw Met>20 GeV
• Raw Ht>100 GeV
• at least 1 track/pi0 cluster with
• N(live)<7
• pT>10 GeV

The results of this cut set compared to the cut set 1 (the same except for the N(live) cut) are

We have reduced the signal by 3.8% and the background by 19%.  Clearly, this cut is a keeper.

During this week’s Tau Group meeting, I showed a comparison of CES Shower energy and the momentum of the matched track, in a sample of conversion electrons.  This number looked fine in 0h data, but looked much worse in 0i data. (The one that I’ve been working on the calibrations for.):

Pasha suggested that, in order to track down this problem, I start by looking at high-Pt electrons. (The same sample the CES calibrations had been trained on) I believe that I’ve tracked down the problem. Continue reading CES absolute Energy Calibration →