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Development of electron neutrino showers at mid and high altitudes in the atmosphere
Available online at www.sciencedirect.com
Nuclear Physics B (Proc. Suppl.) 229–232 (2012) 560 www.elsevier.com/locate/npbps
Development of electron neutrino showers at mid and high altitudes in the atmosphere A.D. Supanitsky, G. Medina-Tanco Departamento de F´ısica de Altas Energ´ıas, Instituto de Ciencias Nucleares, Universidad Nacional Aut´onoma de M´exico, A. P. 70-543, 04510, M´exico, D. F., M´exico.
Abstract JEM-EUSO is a mission intended to detect the fluorescence light produced by the secondary charge particles generated by ultra high energy cosmic rays interacting in the Earth atmosphere. In this work we study in detail the characteristics of longitudinal profiles of electron neutrino showers which, in regions of large air density are dominated by the Landau Pomeranchuk Migdal (LPM) effect. We believe that these characteristics have grate importance for its identification when such showers are observed from the space. Keywords: High energy neutrinos, Orbital detectors
The very large exposure of the JEM-EUSO [1] telescope is ideal for the detection of high energy neutrinos. The information carried by the high energy neutrino component is of grate importance for the understanding of several processes related to ultra high energy cosmic ray physics. High energy neutrinos that propagate in the Earth atmosphere can interact with protons and neutrons of the air molecules. There are two possible channels for this interaction, charge and neutral current. In this work, the simulation of the neutrino nucleon interaction is performed by using the PYTHIA code [2]. The parton distribution function (PDF) library LHAPDF [3] is linked with PYTHIA in order to be able to use different extrapolations of the PDFs. In this work the CTEQ6 [4] set of PDFs is considered. The longitudinal profile of the shower is simulated by inserting the particles generated with PYTHIA in the fast Monte Carlo CONEX [5]. Because the mean free path of neutrinos propagating in the atmosphere is very small, they can interact very deeply, after traversing a large amount of matter. Horizontal electron neutrino showers of Eν = 1020 eV are generated for different altitudes. They are injected on 0920-5632/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysbps.2012.10.001
the vertical axis of the JEM-EUSO field of view in the nadir position. At sea level, the showers present large fluctuations due to the LPM effect, the longitudinal profiles have several peaks placed at different atmospheric depths. The first peak (counted from the beginning of the shower) is related to the hadronic part of the cascade and its position is deeper for showers where the electron takes a large fraction of the incident neutrino energy (“more electromagnetic”). As the altitude increases the development of the showers is less affected by the LPM effect, then, the fluctuations decrease and also the probability to find more than one peak in the longitudinal profile (see Ref. [6] for details). In particular, the probability to find just one maximum in the longitudinal profile at sea level is ∼ 65%, at 5 km of altitude ∼ 76%, at 10 km ∼ 89% and at 20 km ∼ 99%. References [1] [2] [3] [4] [5] [6]
G. Medina-Tanco et al., these proceedings. T. Sjostrand, S. Mrenna, P. Skands, JHEP 0605, 026 (2006). M. Whalley et al., http://hepforge.cedar.ac.uk/lhapdf/. P. Nadolsky et al., Phys. Rev. D78, 013004 (2008). T. Bergmann et al., Astropart. Phys. 26, 420 (2007). A.D. Supanitsky et al., 30th ICRC, Poland, # 1424 (2009).
Nuclear Physics B (Proc. Suppl.) 229–232 (2012) 560 www.elsevier.com/locate/npbps
Development of electron neutrino showers at mid and high altitudes in the atmosphere A.D. Supanitsky, G. Medina-Tanco Departamento de F´ısica de Altas Energ´ıas, Instituto de Ciencias Nucleares, Universidad Nacional Aut´onoma de M´exico, A. P. 70-543, 04510, M´exico, D. F., M´exico.
Abstract JEM-EUSO is a mission intended to detect the fluorescence light produced by the secondary charge particles generated by ultra high energy cosmic rays interacting in the Earth atmosphere. In this work we study in detail the characteristics of longitudinal profiles of electron neutrino showers which, in regions of large air density are dominated by the Landau Pomeranchuk Migdal (LPM) effect. We believe that these characteristics have grate importance for its identification when such showers are observed from the space. Keywords: High energy neutrinos, Orbital detectors
The very large exposure of the JEM-EUSO [1] telescope is ideal for the detection of high energy neutrinos. The information carried by the high energy neutrino component is of grate importance for the understanding of several processes related to ultra high energy cosmic ray physics. High energy neutrinos that propagate in the Earth atmosphere can interact with protons and neutrons of the air molecules. There are two possible channels for this interaction, charge and neutral current. In this work, the simulation of the neutrino nucleon interaction is performed by using the PYTHIA code [2]. The parton distribution function (PDF) library LHAPDF [3] is linked with PYTHIA in order to be able to use different extrapolations of the PDFs. In this work the CTEQ6 [4] set of PDFs is considered. The longitudinal profile of the shower is simulated by inserting the particles generated with PYTHIA in the fast Monte Carlo CONEX [5]. Because the mean free path of neutrinos propagating in the atmosphere is very small, they can interact very deeply, after traversing a large amount of matter. Horizontal electron neutrino showers of Eν = 1020 eV are generated for different altitudes. They are injected on 0920-5632/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.nuclphysbps.2012.10.001
the vertical axis of the JEM-EUSO field of view in the nadir position. At sea level, the showers present large fluctuations due to the LPM effect, the longitudinal profiles have several peaks placed at different atmospheric depths. The first peak (counted from the beginning of the shower) is related to the hadronic part of the cascade and its position is deeper for showers where the electron takes a large fraction of the incident neutrino energy (“more electromagnetic”). As the altitude increases the development of the showers is less affected by the LPM effect, then, the fluctuations decrease and also the probability to find more than one peak in the longitudinal profile (see Ref. [6] for details). In particular, the probability to find just one maximum in the longitudinal profile at sea level is ∼ 65%, at 5 km of altitude ∼ 76%, at 10 km ∼ 89% and at 20 km ∼ 99%. References [1] [2] [3] [4] [5] [6]
G. Medina-Tanco et al., these proceedings. T. Sjostrand, S. Mrenna, P. Skands, JHEP 0605, 026 (2006). M. Whalley et al., http://hepforge.cedar.ac.uk/lhapdf/. P. Nadolsky et al., Phys. Rev. D78, 013004 (2008). T. Bergmann et al., Astropart. Phys. 26, 420 (2007). A.D. Supanitsky et al., 30th ICRC, Poland, # 1424 (2009).