Transcript mants
Shower along muon track Salvatore Mangano (IFIC) 1/12 Muon energy loss Below 1 TeV: Continuous energy loss Above 1 TeV: Discrete energy loss Large energy fluctuation => Electromagnetic showers Motivation • Extract more information many muons have showers additional variables (shower multiplicity) • Not explored yet numbers of showers per track length => energy estimator • Distinguish event topologies charged current interaction tau-decay 3/12 Identification Method Muon emits: continuously Cherenkov photons and sometimes discrete electromagnetic showers After a transformation: Peak signals shower position 4/12 Algorithm 1. Take muon direction 2. Calculate photon emission positions (weight=1) Ealry times (|20 ns|) late times (20-250 ns) Cerenkov emission spherical emission 3. Search shower candidates 5/12 Simulation and selection • • • • Corsika simulation with background (Horandel, QGSJET,KM3) 1-5 line configuration Muon selection at least 125 m long • Shower selection 10 hits in 10 m => hard cuts 5 hits in 20 m => soft cuts 5 hits from different floors Photon emission along MC muon track all reconstructed emission points of the photons on muon trajectory hits selected by the algorithm positions of generated showers along the muon direction 7/12 Muon and shower energy Averaged muon energy: All: 1.2 TeV Soft: 2.4 TeV Hard: 3.2 TeV Averaged shower energy: 160 GeV 200 GeV 460 GeV Shower efficiency and purity n_gen = MC hits in at least 5 diff. LCM and produced in detector n_rec = shower position |x_gen – x_rec| < 25 m Shower efficiency = n_rec/n_gen Shower purity = n_rec/n_rec^all Number of showers versus muon energy More showers=>higher muon energy Light deposit of showers Different primary models Number of showers per muon Tested for 2007 data (47 days of lifetime) Shower energy 0.5TeV Muon energy with shower 3.7TeV Position resolution 10m Shower Efficiency 5% Shower Purity 70% Main systematic errors: • Water absorption length • PMT acceptance 12/12 Conclusion Analysis Idea: project the hit information to muon-axis search significant peaks => identification of muons with showers Goal: Shower multiplicity to distinguish different MC Back up slide Reduction to one dimensional problem by projection on the muon direction Downgoing muon (5 lines) Detected photon Used in fit Result of muon reconstruction Flat distribution of photons on muon trajectory 16/12 Downgoing muon with shower Result of the 3D shower reconstruction Peak=Shower position on muon trajectory 17/12 Shape of number of showers Driven by Binomial formula! (Works only for high purity) entries with 2 gen. showers times 2 (efficiency not to detect a shower) entries with 1 gen shower times efficiency not to detect a shower entries with 0 gen. shower entries with 0 rec. shower n0,rec n0, gen n1, gen (1 ) n2, gen (1 ) 2 .... n1,rec n1, gen n2, gen (1 ) n3, gen (1 ) 2 ....