Using CORSIKA for simulating extensive air showers, we study the relation
between the shower characteristics and features of hadronic multiparticle
production at low energies. We report about investigations of typical energies
and phase space regions of secondary particles which are important for muon
production in extensive air showers. Possibilities to measure relevant
quantities of hadron production in existing and planned accelerator experiments
are discussed.Comment: To be published in Proceedings of ICRC 2005, 29th International
  Cosmic Ray Conferenc

Bluemer, J.

Engel, R.

Haungs, A.

Meurer, C.

Roth, M.

English

arXiv

Using CORSIKA for simulating extensive air showers, we study the relation between the shower characteristics and features of hadronic multiparticle production at low energies. We report about investigations of typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers. Possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed

Meurer, Christine

Blümer, Johannes

Engel, Ralph

Haungs, Andreas

Roth, Markus

Hochschulschriftenserver - Universität Frankfurt am Main

arXiv:astro-ph/0506755 v1   30 Jun 200529th International Cosmic Ray Conference Pune (2005) 00, 101–106Hadronic multiparticle production in extensive air showers andaccelerator experimentsC. Meurera, J. Bl¨ umerb, R. Engela, A. Haungsa, M. Rothb(a) Forschungszentrum Karlsruhe GmbH, Postfach 3640, D-76021 Karlsruhe, Germany(b) Universit¨ at Karlsruhe (TH), Postfach 6980, D-76128 Karlsruhe, GermanyPresenter: M. Roth (Markus.Roth@ik.fzk.de), ger-roth-M-abs1-he21-oralUsingCORSIKA forsimulatingextensiveair showers,westudytherelationbetweentheshowercharacteristicsand features of hadronic multiparticle productionat low energies. We report about investigations of typical en-ergies and phase space regions of secondaryparticles which are importantfor muonproductionin extensive airshowers. Possibilities to measure relevant quantities of hadron production in existing and planned acceleratorexperiments are discussed.1. IntroductionOne of the most promising approaches to determine the energy spectrum and composition of the cosmic rayswith energies above 1015 eV is the measurement of the number of electrons and muons produced in extensiveair showers (EAS). However the results of such a shower analysis are strongly dependent on the hadronicinteraction models used for simulating reference showers [1]. Therefore it is important to study in detail therole of hadronic interactions and in particular the energy and secondary particle phase space regions that aremost important for the observed characteristics of EAS.The electromagneticcomponentofa showeris well determinedby the depthof maximumand the energyof theshower. Due to the electromagnetic cascade, having a short radiation length of ∼ 36g/cm2, any informationon the initial distribution of photons produced in π0 decays is lost. Therefore the electromagnetic showercomponent depends on the primary particle type only through the depth of shower maximum. In contrast, themuon component is very sensitive to the characteristics of hadronic interactions. Once the hadronic showerparticles have reached an energyat which chargedpions and kaons decay, they producemuons which decouplefrom the shower cascade. The muons propagateto the detector with small energyloss and deﬂection and hencecarryinformationon hadronicinteractionsin EAS. Due to the competitionbetweeninteractionand decay,mostof the muons are decay products of mesons that are produced in low-energy interactions. Therefore it is notsurprising that muons in EAS are particularly sensitive to hadronic multiparticle production at low energy [2].Recent model studies show that even at ultra-high shower energies the predictions on the lateral distribution ofshower particles depend strongly on the applied low-energy interaction model [3].2. Muon production in extensive air showersMotivated by the measurementconditionsof the KASCADE array [4], we considershowers with a primaryen-ergy of 1015 eV and apply a muon detection threshold of 250MeV. Using a modiﬁed version of the simulationpackage CORSIKA [5] we have simulated two samples of 1500 vertical and inclined (60◦) protonand 500ironinduced showers. Below 80GeV the low-energy hadronic interaction model GHEISHA 2002 [6] and above80GeV the high-energy model QGSJET 01 [7] are applied. In the following only vertical proton showers arediscussed. The results are very similar for iron induced showers and also for zenith angles up to 60◦.2 C. Meurer et al.Table 1. Particle types of mother andgrandmother particles in a vertical protoninduced shower at 1015eV.mother grandmotherpions 89.2% 72.3%kaons 10.5% 6.5%nucleons - 20.9%In Fig. 1 the energy distribution of muons at detector level(1030g/cm2) is shown for several lateral distance ranges. The max-imum of this distribution shifts to lower energies for larger lateraldistances. Most likely four to ﬁve consecutive hadronic interactions(number of generations) take place before a hadron decays into amuon, see Fig. 2. Here and in the following we consider only thosemuons that reach the ground level with an energy above the detec-tion threshold. The number of generations show no signiﬁcant de-pendence on the lateral distance. To study the hadronic ancestors of muons in EAS, we introduce the termsgrandmother and mother particle for each observed muon. The grandmother particle is the hadron inducingthe last hadronic interaction that ﬁnally leads to a meson (mother particle) which decays into the correspond-ing muon. Most of the grandmother and mother particles are pions, but also about 20% of the grandmotherparticles are nucleons and a few are kaons. Details of the composition of mother and grandmotherparticles aregiven in Tab. 1.) (GeV) m ( kin E0 2 4 6 8 10kin dN/dEkinE-2 10-1 101102 103 10) (GeV) m ( kin E1 102 103 104 10   0m < R < 500m  200m < R < 500m   50m < R < 200m    0m < R <  50m Figure 1. Simulated energy distribution of muons for dif-ferent lateral distances.gen N0 2 4 6 8 10 12 14gen/dNm dNm1/N-3 10-2 10-1 10 0m < R < 500m  200m < R < 500m  50m < R < 200m  0m < R < 50m Figure 2. Averaged number of generations before produc-ing a muon visible at ground level (shown for various lat-eral distances).3. Energy and phase space regionsThe energy spectra of different grandmother particles are shown in Fig. 3 (left). They cover a large energyrange up to the primary energy with a maximum at about 100GeV. The peak at 106 GeV in the nucleon energyspectrum shows that also a fraction of muons stems from decays of mesons produced in the ﬁrst interactionin a shower. Furthermore, the step at 80GeV clearly indicates a mismatch between the predictions of thelow-energy model GHEISHA and the high-energy model QGSJET. In Fig. 3 (right) the grandmother particleenergyspectrum is shown for different ranges of lateral muon distance. The maximumshifts with larger lateraldistance to lower energies. Comparing the last interaction in EAS with collisions studied at accelerators, onehas to keep in mind that the grandmother particle corresponds to the beam particle and the mother particle isequivalent to a secondary particle producedin e.g. a minimum bias p-N interaction. The most probable energyof the grandmother particle is within the range of beam energies of ﬁxed target experiments e.g. at the SPSaccelerator at CERN.Hadronic multiparticle production in extensive air showers and accelerator experiments 3 (GeV) kin E0 2 4 6 8 10 12 14kin dN/dEkinE-1 101102 103 10 (GeV) kin E1 102 103 104 105 106 10± pN± K (GeV) kin E0 2 4 6 8 10 12 14kin dN/dEkinE1102 103 10 (GeV) kin E1 102 103 104 105 106 10 200m < R < 500m   50m < R < 200m    0m < R <  50m Figure 3. Energy distribution of grandmother particles. Left: different grandmother particle types; lateral distance rangeof muons at ground level: 0-500m. Right: different lateral distances; all particle types are summed up.Table 2. For the analysis used energy and lateral distance ranges.energy range average energy lateral distance range80-400GeV 160GeV 50-200m30-60GeV 40GeV 200-600mThe further study of the relevant phase spaceof the mother particles is done for two differentgrandmother energy ranges and lateral distanceranges of muons at ground level, see Tab. 2. Thelateral distance ranges are chosen to resembletypical lateral distances measuredat KASCADEand KASCADE-Grande, respectively. In Fig. 4 the rapidity spectra of mother particles (left: pions, right:kaons) are compared to the spectra of secondary particles of proton-carboncollisions and proton-air collisionssimulated with QGSJET labeled as ﬁxed target. The spectra of mother particles in air showers are scaled toﬁt the falling tail of the ﬁxed-energy collision spectra. No signiﬁcant differences are found comparing the ra-pidity distributions of secondary particles in proton-carbon and proton-air collisions. As a consequence of thedifferent selection criteria, the forward hemisphere in the mother rapidity spectra is clearly favoured comparedto the spectra of secondaries in minimum bias collisions.beam  y/y0 0.2 0.4 0.6 0.8 1 1.2dN/dy05101520 fixed target, p+air fixed target, p+C EAS,          p+airp beam y/y0 0.2 0.4 0.6 0.8 1dN/dy00.51 fixed target, p+air fixed target, p+C EAS,          p+airKFigure 4. Rapidity distributions of mother particles (ﬁlled curves) compared with rapidity distributions of secondary par-ticles in simulated single p+C (solid line) and simulated p+air (dashed line) collisions. Left: pions. Right: kaons. Theenergy range of the grandmother particle is limited to 80-400GeV and the lateral distance of the muons to 50-200m tomatch experimentally accessible regions. The ﬁxed target collision simulation is done at 160GeV, corresponding approxi-mately to the mean grandmother energy. The rapidity is normalized to the rapidity of the beam and grandmother particles,respectively.4 C. Meurer et al.4. Conclusions and outlookTable 3. Phase space regions of hadronic interactions rel-evant for muon production in EAS.average energy (GeV) y/ybeam p⊥ (GeV/c)160 0.3 - 1.1 0.0 - 0.740 0.3 - 1.1 0.0 - 1.0Due to the interplay between decay and interaction ofpions and kaons, low energy hadronic interactions arevery important for muon production in extensive airshowers. With increasing lateral distance the mean en-ergy of these interactions, which are mainly initiatedby pions and nucleons, decreases. The phase space re-gions of relevance to EAS are shown in Fig. 5 and summarized in Tab. 3. The most important interactionenergies and phase space regions fall in the range accessible to ﬁxed target experiments with large acceptancedetectors such as HARP, NA49, and MIPP (see also [8] and Refs. therein). Therefore ﬁxed target measure-ments could be used to improve low energy interaction models that can be independently cross-checked bymuon measurements in EAS.beam y/y0 0.2 0.4 0.6 0.8 1 1.2(GeV/c)tp00.20.40.60.81pKbeam y/y0 0.2 0.4 0.6 0.8 1 1.2(GeV/c)tp00.20.40.60.81pKFigure 5. Phase space of mother particles. Left: grandmother energy range: 80-400GeV. Right: 30-60GeV. The ﬁlledsymbols show the distribution for pions, the open symbols for kaons. The large box (red) indicates the most interestingphase space region which includes more than 90% of this particles.Acknowledgements: The authors thank Dieter Heck for many fruitful discussions and help with modifyingCORSIKA to include the muon ancestor information.References[1] T. Antoni et al. (KASCADE Collab.) Astropart. Phys. in press, astro-ph/0505413.[2] R. Engel, T.K. Gaisser, and T. Stanev, Proc. of ISMD, Providence, Rhode Island, August 9-13, 1999,World Scientiﬁc (2000), p. 457; H.J. Drescher and G. Farrar, Astropart. Phys. 19 (2003) 235.[3] H.J. Drescher, M. Bleicher, S. Soff, H. St¨ ocker, Astropart. Phys. 21, 87-94 (2004); D. Heck et al., Proc.of 28th ICRC, Tsukuba, Japan, (2003) p. 279.[4] T. Antoni et al. (KASCADE Collab.) Nucl. Instr. Meth. A 513 (2003) 490.[5] D. Heck, J. Knapp, J. Capdevielle, G. Schatz and T. Thouw, FZKA 6019, ForschungszentrumKarlsruhe,1998.[6] H. Fesefeldt, Report PITHA-85/02, RWTH Aachen, 1985.[7] N.N. Kalmykov, S. Ostapchenko, and A.I. Pavlov, Nucl. Phys. B (Proc. Suppl.) 52B (1997) 17.[8] G. Barr and R. Engel, Proc. of 13th ISVHECRI, Pylos, Greece, (2004) submitted to Nucl. Phys. B,astro-ph/0504356.

World Scientiﬁc

Hadronic multiparticle production in extensive air showers and accelerator experiments

http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.317.7061

Hadronic multiparticle production in extensive air showers and
  accelerator experiments

Hadronic multiparticle production in extensive air showers and accelerator experiments

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