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Search for upward-going air showers with the fluorescence detector of the Pierre Auger Observatory

by Emanuele De Vito for the Pierre Auger Collaboration

This is not the latest submitted version.

Submission summary

As Contributors: Emanuele De Vito
Preprint link: scipost_202202_00031v1
Date submitted: 2022-02-16 13:01
Submitted by: De Vito, Emanuele
Submitted to: SciPost Physics Proceedings
Proceedings issue: 16th International Workshop on Tau Lepton Physics (TAU2021)
Academic field: Physics
Specialties:
  • Gravitation, Cosmology and Astroparticle Physics
  • High-Energy Physics - Experiment
Approach: Experimental

Abstract

The fluorescence detector (FD) of the Pierre Auger Observatory is sensitive to upward-going air showers for energies above 10^17 eV. Given its operation time and wide field of view, the FD has the potential to support or constrain the recent “anomalous” observations by the ANITA detector, interpreted as upward-going air showers of unexplained nature. We have used 14 years of data collected by the FD to search for upward-going showers using a set of quality selection criteria defined using 10% of the full data sample. To distinguish candidates from false positives, calculate the exposure and obtain the expected background, dedicated simulations for signal (upward-going events) and background (downward-going events) have been performed. Results of the analysis after unblinding the data set are presented. Finally, the exposure and sensitivity for the specific scenario of a signal being ascribed to tau lepton decay are calculated and the corresponding upper limits are shown as a function of primary energy and in different zenith angle ranges.

Current status:
Has been resubmitted


Submission & Refereeing History

Resubmission scipost_202202_00031v2 on 11 May 2022

Reports on this Submission

Report 1 by Michele Doro on 2022-5-3 (Invited Report)

Report

Dear authors

apologies for the delay in the review. The proceedings are well written, clear and the results and methods are sound. I only have few minor remarks and curiosities:
* you did not mention how did you choose the 10% test dataset, and whether the acceptance was constant during the 14y operation
* the justification of X=0.55 is rather vague. Can't you estimate a false negative/false positve/power of your test?
* when mentioning the figures you should mention left/right

That's it

Requested changes

* when mentioning the figures you should mention left/right

  • validity: ok
  • significance: ok
  • originality: good
  • clarity: high
  • formatting: good
  • grammar: excellent

Author:  Emanuele De Vito  on 2022-05-11  [id 2455]

(in reply to Report 1 by Michele Doro on 2022-05-03)

Dear reviewer,
thanks for your comments and suggestions.
The 10% data set has been chosen by requiring the presence of the number 1 in the millisecond GPS timestamp. Therefore the events have been almost "randomly" chosen from the entire data sample. The acceptance of our detector was not constant during the 14 years of operation but we have used Monte Carlo simulations that reproduce the realistic DAQ condition of the detector with high accuracy (in bins of 10 minutes). This will guarantee that simulations and data are consistent at large extent.
The value X=0.55 has been set making a scan through the whole X range and selecting the value that maximize our exposure (i.e. minimize our upper limit). Our upper limit was set with a confidence level of 95% (Feldman and Cousins), we have added a line in the text to specify it.
Finally we also modified the inline reference to figures by adding a left/right as you required.
Best regards.
Emanuele De Vito

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