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Speed Based Analysis of HiRes Data Set. Adam Blake, June 9 th 2008. Overview. Results Quick Review Look at Some Data In Depth Look at One Anomalous Event Conclusion. Results – June 1, 2008. *By obviously bad, one of the following is true: The plane did not fit right
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Speed Based Analysis of HiRes Data Set Adam Blake, June 9th 2008
Overview • Results • Quick Review • Look at Some Data • In Depth Look at One Anomalous Event • Conclusion
Results – June 1, 2008 • *By obviously bad, one of the following is true: • The plane did not fit right • The event is just noise • The event is on May 19th, 2004 • † Will explain seperately
Up to this point Quick Review
Correcting Time and Finding Distance Along Shower Axis • Basic Problem: • Find the closest point of approach for two lines in 3D space. Uv b Rp Mv Shower Axis a Tv
Correcting Time and Finding Distance Along Shower Axis • From this calculation, b is now the slant depth (or distance along shower axis measured from Rp. • The time is calculated from the following formula: Uv b Rp Mv Shower Axis a Tv Because this formula relies on the tube time given in data, the reconstruction cannot use timing information to improve plane fits or to find the shower axis.
Cuts Data Processing Cuts My Cuts • Both detectors must pass plane fits • Minimum PE per tube: 1.0 • Minimum Tubes per event: 6 • Minimum Average PE per tube per event: 15.0 • Maximum Track Length: Hr1 – 36.0°, Hr2 – 57.0° • Minimum Track Length: • Hr1 – 3°, Hr2 – 6° • Cut if event crossing planes or tube binning • 10° > Opening Angle • 170° < Opening Angle • Bootstrap σ > .0012 m/ns • Hr1 adjusted tubes < 3 • Hr2 adjusted tubes < 6 • Track Length < 8 degrees • Tubes in 1 mirror > 170 • Ψ > 120 • Plog < 2.0 • Rp < 4km from either site • Speed difference to Error difference ratio*
How Cuts Have Been Determined Compare standard deviation calculated in standard way to percentage of data cut. Look for obvious breaks in the data. At these points, calculate width and full width at half max of fits to binned data and look for appropriate statistical relations. Comparison of percentage data cut and drop in standard deviation for Bootstrap estimated error of HiRes 2.
Ratio Cut This is the ratio of the difference in speeds to the combined error in the speeds calculated using the bootstrap method. The errors are correlated, so the covariant part of the correlation must be accounted for.
Resulting Distribution Resulting histograms for HiRes 1 and HiRes 2
HiRes 1 Histogram Developed from set of 26000 Iron MC events thrown at the speed of light with energy 10E19, ~4500 of which made it through pass 4 and ~1800 made it through my cuts.
HiRes 2 Histogram Developed from set of 26000 Iron MC events thrown at the speed of light with energy 10E19, ~4500 of which made it through pass 4 and ~1800 made it through my cuts
Apertures * Cuts are being reevaluated. This graph is done using current cuts but may change slightly. Proposed new cuts would increase apertures shown. Currently awaiting processing for other apertures.
Just a brief mention of what has been done with previous sets of “abnormal” events Closer Look
Data Set Notes • Starting with first processed data runs in January, a good deal of effort has been put into looking at individual events to see why they have abnormal speeds. • Overall, the number of events that were not “well understood” has changed from several hundred to the 11 mentioned earlier. • Next slides: An example of what has been done.
Plane Fit Comparison Mono Plane Fits Stereo Plane Fits
July 27th, 2001 • When I try to fit this, I get a vertical plane for HiRes 2 • This type of event is reason for current Rp cut. The shower goes right over the top of the detector so planes do not fit well. This throws speed off.
This event is the event I have spent the most time on to this point. Other possible candidates will receive similar treatment. In Depth Event
In Depth Event • The decision to focus on this event first resulted from: • Good track in both mirrors • Both Hr1 and Hr2 speeds match very closely • Reconstructed Energy was available for this event from HiRes 2 Mono • Speed is > 7 sigma from speed of light • Other events will receive similar treatment to this event. • This event has no HiRes 1 mono. It only has 6 good HiRes 1 tubes. That is enough to pass my cuts and stereo cuts but not mono. • The various models used to try and explain this event have resulted in explanations for almost every other abnormal event – however they have not resulted in an explanation for this event.
Various Speed Fits • Shower_speed is speed fit by my program • sab_plane_fit is speed fit after refitting the plane using a plane fitter I wrote • Shower_speed/Origin is speed fit by Origin based on points from shower_speed • Hires_Soft/Mathematica is the HiRes plane fit used with Mathematica to correct tube times then fit in Origin • Hires_Soft/Mathematica no weight is the HiRes plane fit used with mathematica to correct tube times then fit in Mathematica with no additional weighting • No Correction, No weight is a fit performed straight on HiRes raw data with no corrections.
Plane Fit Comparisons • Comparison for plane vectors done by various fitting • Rutgers and HiRes planes use relative timing to aide in plane fitting.
Parameter Comparison • Comparison for various parameters. • Mine refers to parameters calculated using my planes and Mathematica • Reconstruction are values pulled from reconstruction.
Looking at this another wayCan I reproduce this effect in Monte Carlo events?
What happened with this event? The Reconstructed plane fits do not match the pre-reconstruction plane fits.
Plane Comparison HiRes 1 planes HiRes 2 planes
Plane Comparison Actual Planes Reconstructed Planes
Shifting the Planes – Work in Progress Theta consists of a rotation about the z axis. Psi is a rotation about the axis perpendicular to both shower normal and shower core. This is a non-weighted fit to HiRes 2 points
Current State • Still have a finite number of events that reconstruct with unusual speeds. • Currently looking at rotating planes to see what would need to be done for planes to fit • Also currently in the process of reevaluating cuts based on some slight changes to procedure • Calculating Apertures with new cuts