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Study of cosmic ray shower front and time structure with ARGO-YBJ . A. Karen C. M., Lorenzo Perrone. NEW FEATURES Larger statistics simulations. Allows comparison of simulation to data. Definition of observables. ….from ICRC07. - PowerPoint PPT Presentation
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Study of cosmic ray shower front
and
time structure with ARGO-YBJ
A. Karen C. M., Lorenzo Perrone
NEW FEATURES
Larger statistics simulations
Allows comparison of simulation to data
Definition of observables
1. The curvature of the shower front as the mean of time residuals with respect to a planar fit (Td)
2. The thickness of the shower front as the root mean square (RMS) of time residuals with respect to a conical fit (TS)
….from ICRC07
Definition of observables
Shower axis - trajectory of the incident primary cosmic ray particle towards the obervation level
Shower plane – plane perpendicular to the shower axis
R – radial distance from the shower core
The shower disk refers to the curved disk of secondary shower particles towards earth
….from Kascade-Grande
Mean arrival time vs distance to shower core
Thickness vs distance to shower core
….from Kascade-Grande
Shower Reconstruction
Conical Fit
2E
PE
PE0
PP
2 )mcyl
cxtt(
EEEEEE sinsinm and cossinl
2PE
PE
PE0
PP
2 )c
Rmc
ylc
xtt(
Planar Fit
In EAS experiments for an event E the time tEP can be measured on each fired detector unit P, whose position (xP,yP) is well known
Primary direction cosines
angle azimuth
angle zenith
E
E
This quantity is not a proper 2 . Indeed the measurement unit is ns2
Data Selection
•A successful reconstruction of the global shower observables is required
•Nhit > 20
•Reconstructed shower core coordinates are within the central carpet
• Sub-sample well reconstructed days 006-007 2009 (new data sample)
•Zenith angle less than 15°
Room left for more accurate event selection and quality cuts
Cuts used for ICRC07
Data
Mean of the time residuals (from Planar fit) profile as a function of the core distance
for different pad multiplicities
Shower curvature
Data
RMS of time residuals (from Conical fit) profile as a function of the core distance
for different pad different multiplicities
Shower thickness
statistical errors :errors on the mean
Larger statistics simulationsLarger statistics simulationsProduction of Corsika showers with Grid
- Corsika 6720- SIBYLL as high energy interaction model- FLUKA as low energy interaction model- dN/dE ~ E-1 300 GeV - 300 TeV- dN/d ~ sincos 0-45°
Used ce :pi.infn.itba.infn.itna.infn.it (only tested)ihep.ac.cn (only tested)cnaf.infn.it (heavyly used)
Used se : ts.infn.it
August 2008 - December 2008
~ 107 showers ~ 2.3 Tera
Generated Sample vs Energy-ZenithGenerated Sample vs Energy-Zenith
10 TeV
100 TeV
1 TeV
Processing through argog at CNAFProcessing through argog at CNAF
Generation area: 200× 200 m2
Each shower is used up to 10 times after re-sampling the core position
Overall simulated data set ~ 107 events
Argog processing time at CNAF: 100 CPU ~36 hours
Motivation: cross checking the dependence on hadronic models for the cross-section analysis and time front structure
100 TeV
10 TeV
Simulated Events vs Energy-AngleSimulated Events vs Energy-Angle
1 TeV
100 TeV
10 TeV
Usage of individual showers vs Energy-AngleUsage of individual showers vs Energy-Angle
1 TeV
Xmax from corsika fit to the longitudinal profiles included in the produced corsika binary files
SummarySummary
- The production on GRID relatively smooth (GRID malfunctioning limited to short time windows)
- Problems with the ``time bomb'' implemented in FLUKA. This periodically requires a new installation if the production takes longer than few months. (FLUKA doesn't distribute the source code. No way to by-pass this ``feature'' in a clean way). It makes almost impossible to reproduce a given shower generated in the ``past''
Common problem for several experiments. The community is considering to move to UrQMD . It behaves similarly as FLUKA at least in the TeV
range (Geisha is not manteined any longer)
Showers available at /storage/gpfs_argo1/Production/MC/Corsika6.7201/storage/gpfs_argo1/Production/MC/Corsika6.7201 2.3 Tb 2.3 Tb
Simulation
Mean of the time residuals (from Planar fit) profile as a function of the core distance
for pad different multiplicities
Shower curvature
Simulation
RMS of time residuals (from Conical fit) profile as a function of the core distance
at different multiplicities
Shower thickness
statistical errors :errors on the mean
Comparison data with MC
Zenith Angle distribution
Comparison data with MC
Mean of the time residuals (from Planar fit) profile: good agreement between data and simulation
Comparison data with MC
Mean of the time residuals (from Planar fit) profile: good agreement between data and simulation
Comparison data with MC
Mean of the time residuals (from Planar fit) profile: sensible differences between data and simulation for lower pad multiplicities
Comparison data with MC
RMS of time residuals (from Conical fit) profile: to be investigated
nhit 200-400
Moderate correlation of conicity with Xmax for protons
What else can we learn of shower phenomenology…..
New fit with alpha free
true value
Observable
What’s more….
Recommended