1. The muon component in extensive air showers and its relation to hadronic multiparticle production Christine Meurer Johannes Blümer Ralph Engel Andreas Haungs Markus Roth and the HARP Collaboration Christine Meurer Johannes Blümer Ralph Engel Andreas Haungs Markus Roth and the HARP Collaboration HARP Detector, CERN Auger Observatory, Argentina

2. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer2/30 Outline Relation of muons in extensive air showers (EAS) to hadronic interactions Comparison: EAS – fixed target experiment Investigation of phase space Existing accelerator data New measurements: NA49 and HARP Conclusions and outlook

3. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer3/30 Motivation Interpretation of CR data relies heavily on MC simulations MC uncertainties arise predominantly from hadronic interaction models Muons are one of the main ingredients to infer E, A Muon component is very sensitive to hadronic interactions Which hadronic interactions are of major importance for muon production?

4. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer4/30 Composition at the knee KASCADE T. Antoni et al. Astropart.Phys.24(2005)1 Differences mainly due to muon production or total

5. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer5/30 Muon production in EAS proton E =10 15 eV  = 0° Primary particle CORSIKA simulations: QGSJET-01QGSJET-01 GHEISHAGHEISHA 1 2 3 On average 6 interactions before muon productionOn average 6 interactions before muon production Number of generations increases with smallerNumber of generations increases with smaller muon energy threshold number of generations

6. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer6/30 Muon energy on ground lateral distance R Primary particle Core p ++ ++ ++  e-e- e+e+ ++ 00 00 -- -- p -- -- -- n e-e- e+e+ p ++    p --  E   smaller for larger distances proton E =10 15 eV  = 0° muon energy

7. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer7/30 Relation of muons to hadronic interactions Last interaction p ++++ ++ ++++  e-e- e+e+ ++ 00 00 -- -- p ---- -- -- n e-e- e+e+ p ++    p -- proton E =10 15 eV  = 0° GHEISHA QGSJET01 mother detected muon grandmother mother pion72.3%89.2% nucleon20.9%- kaon6.5%10.5% grandmother energy

8. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer8/30 EAS vs fixed target experiment + Several targets + Forward direction accessible + Relevant energy range: 8-1000 GeV Grandmother particle = beam particle Mother particle = secondary particle p+C p ++++ ++ ++++  e-e- e+e+ ++ 00 00 -- -- p ---- -- -- n e-e- e+e+ p ++    p --

9. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer9/30 Rapidity of pions Rapidity: Forward hemisphere dominating Interesting range: 0.3 < y/y beam < 1.1 EAS: KASCADE range: 50-200m Nucleons (~160GeV) + air Fixed target: p(160GeV) + air, p(160GeV) + C (QGSJET-01)y beam = 5.8

10. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer10/30 Rapidity of pions Energy loss/ muon decay: muons not detected No pion decay, but further interactions EAS: KASCADE range: 50-200m Nucleons (~160GeV) + air Fixed target: p(160GeV) + air, p(160GeV) + C (QGSJET-01)y beam = 5.8

11. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer11/30 Rapidity of kaons Energy loss/ muon decay: muons not detected No significant differences because of further interactions → decay energy of kaons higher than for pions EAS: KASCADE range: 50-200m Nucleons (~160GeV) + air Fixed target: p(160GeV) + air, p(160GeV) + C (QGSJET-01)y beam = 5.8 Interesting range: 0.3 < y/y beam < 1.1 Forward hemisphere dominating

12. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer12/30 x lab of secondary  and K  EAS: KASCADE range: 50-200m Nucleons (~160GeV) + air Fixed target: p(160GeV) + air, p(160GeV) + C (QGSJET-01)y beam = 5.8 K

13. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer13/30 Transverse momentum of  and K p t distribution in EAS similar to p t distribution infixed target simulation. → Low transverse momenta of interest p t distribution in EAS similar to p t distribution in fixed target simulation. → Low transverse momenta of interest  EAS: KASCADE range: 50-200m Nucleons (~160GeV) + air Fixed target: p(160GeV) + air, p(160GeV) + C (QGSJET-01)y beam = 5.8 

14. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer14/30 Phase space: E~160GeV y/y beam 0.3-1.1 p t (GeV)0.0-0.7 K KASCADE range: 50-200m; Nucleons (~160GeV) + Air EAS EAS

15. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer15/30 Phase space: E~ 40GeV y/y beam 0.3-1.1 p t (GeV)0.0-1.0 KASCADE-Grande range: 200-500m; Nucleons (~40GeV) + Air K EAS EAS

16. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer16/30 Existing accelerator data: p+Be Data: p+Be →  +X EAS: p+air →  +X

17. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer17/30 Existing p+C data: Barton et al. Data: p+C →  +X EAS: p+air →  +X

18. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer18/30 Data: p+C →  +X EAS: p+air →  +X New p+C data: NA49, HARP Existing: proton beam → 21% of grandmother particle Still needed: pion beam → 72% of grandmother particle

19. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer19/30 NA49: p+C @ 158 GeV/c C.Alt et al. (NA49 collaboration) hep-ex/0606028 Error of NA49 data: stat. error ~ 5% syst. error ~ 5% Comparison: models – data: SIBYLL and QGSJET-II: reasonable agreement with data QGSJET-01: overestimation of factor ~ 1.5

20. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer20/30 NA49: p+C @ 158 GeV/c C.Alt et al. (NA49 collaboration) hep-ex/0606028 QGSJET-01: soft  -spectra QGSJET-II: hard  -spectra

21. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer21/30 HARP: p+C @ 12 GeV/c Ongoing analysis: p+C @ 12 GeV/c Selection of secondary particles (     ) in forward hemisphere using the drift chambers. No of events: 1,000k No of events after cuts: 450k 0 1 2 3 4 5 6 7 8 9 10  p  e  k TOF CERENKOV TOF CERENKOV CALORIMETER Separation of particle types using different detector components p (GeV/c)

22. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer22/30 HARP: p+C @ 12 GeV/c Ongoing analysis: p+C @ 12 GeV/c Selection of secondary particles (     ) in forward hemisphere using the drift chambers. No of events: 1,000k No of events after cuts: 450k 0 1 2 3 4 5 6 7 8 9 10  p  e  k TOF CERENKOV TOF CERENKOV CALORIMETER Separation of particle types using different detector components p (GeV/c) CERENKOV TOF CAL

23. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer23/30 HARP preliminary p+C→  ± +X, p beam =12 GeV/c        leading particle effect Comparison with models in preparation Error: stat. and syst. error → syst. error: kaon subtraction in progress

24. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer24/30 Error estimation Stat. error Syst. error 4% 20% rel. error p (MeV/c)     Dominant contributions to syst. error: Tertiary subtraction Momentum scale

25. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer25/30 Conclusions Interpretation of CR data relies heavily on MC simulations Muons are main ingredients to infer E, A Fixed target experiments are very important for understanding of muon production in extensive air showers Relevant hadronic interactions for muon production are in the  energy range: 8 – 1000 GeV  phase space region: forward hemisphere New (2006) fixed target measurements:  NA49: p+C @ 158GeV/c  HARP: p+C @ 12 GeV/c Comparison: data – models: SIBYLL and QGSJET-II in good agreement with data, QGSJET-01 overestimation of factor ~ 1.5 in dN/dy Outlook: further measurements/analyses planed by NA49, HARP and MIPP

26. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer26/30 Planed future measurements/analyses Energy range and phase space of interest  E beam  8-1000 GeV p0.5-11.0 GeV/c  0-300 mrad p+C @ 15 GeV/c  +C @ 12 GeV/c p+C and  +C @ 30, 40, 50, 158GeV/c p+C,  +C and K+C @ 20, 60, 120GeV/c

27. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer27/30 R. Engel

28. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer28/30

29. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer29/30

30. Auger HSS 08.09.2006 Fermilab/USA Christine Meurer30/30 References [Baker61]Phys. Rev. Lett. 7 (1961) 101 (AGS) [Dekkers65]Phys. Rev. B 137 (1965) 962 (CERN) [Allaby70]CERN Yellow Report 70-12 (1970)(CERN) [Cho71]Phys. Rev. D 4 (1971) 1967 (ZGS) [Eichten72]Nucl. Phys. B 44 (1972) 333 (CERN) [Antreasyan79]Phys. Rev. D 19 N3 (1979) 764 (Fermilab) [Barton83]Phys. Rev. D 27 (1983) 2580 (Fermilab) [Abbott92]Phys. Rev. D 45 (1992) 3906 (AGS) [NA49_06]hep-ex/0606028(SPS) [HARP06]ISVHECRI 06, Weihai(PS)