Non-Pointing Photon Work at UC Santa Cruz / SCIPP

ATLAS RPV/Long-lived Physics Group

November 19 2008

Bruce Schumm, UCSC/SCIPP

Initial goal: include conversions in reconstruction

Mauro Donega, UPenn

• Conversion radius resolution may be good enough to provide an independent constraint on GMSB parameters

• Pointing accuracy of reconstructed conversion may be quite good

Reconstructed radius of material-induced conversions

However: conversions only available in release 14, so must migrate analysis to new release(using 14.2.20; not ideal, but workable for conversions)

Intermediate goal: develop release 14 DPD for non-pointing photon analysis

First step: migrate non-standard photon identification to release 14 via isEMMasks (applied in EVPhotonInserter)

Default vs. Non-Pointing Gamma Selection (?)

Mask Bit Default Criterion NP selection

0 range YES1 Hadronic leakage YES4 Middle energy YES5 Middle ratio 37 NO6 Middle ratio 33 NO7 Middle width NO8 Strips energy ratio YES9 E2,max NO10 E2,max NO11 1st sample width NO12 1st sample shape NO13 Weighted width NO14 Isolation YES

Non-pointing

photon mask is 0x4113

Raw photon container

Default selection

Non-pointingselection

IsEM flag for 50 GMSB events, for various photon ID requirements.

Shown is a decimal representation of a bitwise record of failed photon/electron ID criteria

Next steps for UCSC work:

Need to have at least a crude validation between release 13 and 14 on signal MC truth matching also needs to be explored (GHIT vs. proximity)

Establish “non-pointing photon DPD” (private package)

Add in conversions, explore efficiency and conversion radius resolution

Understand if and how conversion information can enhance understanding of GMSB parameters.

Plan to begin every-other-weekly phone/EVO meetings with non-pointing photon group