# X{sub max}{sup μ} vs. N{sup μ} from extensive air showers as estimator for the mass of primary UHECR's. Application for the Pierre Auger Observatory

## Abstract

We study the possibility of primary mass estimation for Ultra High Energy Cosmic Rays (UHECR's) using the X{sub max}{sup μ} (the height where the number of muons produced on the core of Extensive Air Showers (EAS) is maximum) and the number N{sup μ} of muons detected on ground. We use the 2D distribution - X{sub max}{sup μ} against N{sup μ} in order to find its sensitivity to the mass of the primary particle. For that, we construct a 2D Probability Function Prob(p,Fe | X{sub max}{sup μ}, N{sup μ}) which estimates the probability that a certain point from the plane (X{sub max}{sup μ}, N{sup μ}) corresponds to a shower induced by a proton, respectively an iron nucleus. To test the procedure, we analyze a set of simulated EAS induced by protons and iron nuclei at energies of 10{sup 19}eV and 20° zenith angle with CORSIKA. Using the Bayesian approach and taking into account the geometry of the infill detectors from the Pierre Auger Observatory, we observe an improvement in the accuracy of the primary mass reconstruction in comparison with the results obtained using only the X{sub max}{sup μ} distributions.

- Authors:

- Institute of Space Science, P.O.Box MG-23, Ro 077125 Bucharest-Magurele, Romania and Physics Department, University of Bucharest, Bucharest-Magurele (Romania)
- Physics Department, University of Bucharest, Bucharest-Magurele (Romania)

- Publication Date:

- OSTI Identifier:
- 22390983

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: AIP Conference Proceedings; Journal Volume: 1645; Journal Issue: 1; Conference: Carpathian Summer School of Physics 2014, Sinaia (Romania), 13-26 Jul 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; COSMIC MUONS; COSMIC NUCLEI; COSMIC PROTONS; EEV RANGE; EXTENSIVE AIR SHOWERS; IRON; MUON DETECTION; SENSITIVITY

### Citation Formats

```
Arsene, Nicusor, and Sima, Octavian.
```*X{sub max}{sup μ} vs. N{sup μ} from extensive air showers as estimator for the mass of primary UHECR's. Application for the Pierre Auger Observatory*. United States: N. p., 2015.
Web. doi:10.1063/1.4909587.

```
Arsene, Nicusor, & Sima, Octavian.
```*X{sub max}{sup μ} vs. N{sup μ} from extensive air showers as estimator for the mass of primary UHECR's. Application for the Pierre Auger Observatory*. United States. doi:10.1063/1.4909587.

```
Arsene, Nicusor, and Sima, Octavian. Tue .
"X{sub max}{sup μ} vs. N{sup μ} from extensive air showers as estimator for the mass of primary UHECR's. Application for the Pierre Auger Observatory". United States.
doi:10.1063/1.4909587.
```

```
@article{osti_22390983,
```

title = {X{sub max}{sup μ} vs. N{sup μ} from extensive air showers as estimator for the mass of primary UHECR's. Application for the Pierre Auger Observatory},

author = {Arsene, Nicusor and Sima, Octavian},

abstractNote = {We study the possibility of primary mass estimation for Ultra High Energy Cosmic Rays (UHECR's) using the X{sub max}{sup μ} (the height where the number of muons produced on the core of Extensive Air Showers (EAS) is maximum) and the number N{sup μ} of muons detected on ground. We use the 2D distribution - X{sub max}{sup μ} against N{sup μ} in order to find its sensitivity to the mass of the primary particle. For that, we construct a 2D Probability Function Prob(p,Fe | X{sub max}{sup μ}, N{sup μ}) which estimates the probability that a certain point from the plane (X{sub max}{sup μ}, N{sup μ}) corresponds to a shower induced by a proton, respectively an iron nucleus. To test the procedure, we analyze a set of simulated EAS induced by protons and iron nuclei at energies of 10{sup 19}eV and 20° zenith angle with CORSIKA. Using the Bayesian approach and taking into account the geometry of the infill detectors from the Pierre Auger Observatory, we observe an improvement in the accuracy of the primary mass reconstruction in comparison with the results obtained using only the X{sub max}{sup μ} distributions.},

doi = {10.1063/1.4909587},

journal = {AIP Conference Proceedings},

number = 1,

volume = 1645,

place = {United States},

year = {Tue Feb 24 00:00:00 EST 2015},

month = {Tue Feb 24 00:00:00 EST 2015}

}