arXiv subjects

Thomas K. Gaisser

Publications and source records attributed to Thomas K. Gaisser.

At least 37 records · Page 2Linked to original sources

arXiv2014

A generalized self-veto probability for atmospheric neutrinos

Neutrino telescopes such as IceCube search for an excess of high energy neutrinos above the steeply falling atmospheric background as one approach to finding extraterrestrial neutrinos. For samples of events selected to start in the detector, the atmospheric background can be reduced to the extent that a neutrino interaction inside the fiducial volume is accompanied by a detectable muon from the same cosmic-ray cascade in which the neutrino was produced. Here we provide an approximate calculation of the veto probability as a function of neutrino energy and zenith angle.

astro-ph.HE↗

arXiv2013

Cosmic Ray Energy Spectrum from Measurements of Air Showers

This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 10^14 to 10^20 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.

astro-ph.HE↗

arXiv2013

Atmospheric leptons, the search for a prompt component

The flux of high-energy (>GeV) neutrinos consists primarily of those produced by cosmic-ray interactions in the atmosphere. The contribution from extraterrestrial sources is still unknown. Current limits suggest that the observed spectrum is dominated by atmospheric neutrinos up to at least 100 TeV. The contribution of charmed hadrons to the flux of atmospheric neutrinos is important in the context of the search for astrophysical neutrinos because the spectrum of such "prompt" neutrinos is harder than that of "conventional" neutrinos from decay of pions and kaons. The prompt component therefore becomes increasingly important as energy increases. This paper reviews the status of the search for prompt muons and neutrinos with emphasis on the complementary aspects of muons, electron neutrinos and muon neutrinos.

hep-ph↗

arXiv2012

Spectrum of cosmic-ray nucleons and the atmospheric muon charge ratio

Interpretation of measurements of the muon charge ratio in the TeV range depends on the spectra of protons and neutrons in the primary cosmic radiation and on the inclusive cross sections for production of $π^\pm$ and $K^\pm$ in the atmosphere. Recent measurements of the spectra of cosmic-ray nuclei are used here to estimate separately the energy spectra of protons and neutrons and hence to calculate the charge separated hadronic cascade in the atmosphere. From the corresponding production spectra of $μ^+$ and $μ^-$ the $μ^+/μ^-$ ratio is calculated and compared to recent measurements. The comparison leads to a determination of the relative contribution of kaons and pions. Implications for the spectra of $ν_μ$ and $\barν_μ$ are discussed.

astro-ph.HE↗

arXiv2012

Neutrinos and cosmic rays

In this paper we review the status of the search for high-energy neutrinos from outside the solar system and discuss the implications for the origin and propagation of cosmic rays. Connections between neutrinos and gamma-rays are also discussed.

astro-ph.HE↗

arXiv2012

High Energy Neutrinos from Space

This paper reviews the status of the search for high-energy neutrinos from astrophysical sources. Results from large neutrino telescopes in water (Antares, Baikal) and ice (IceCube) are discussed as well as observations from the surface with Auger and from high altitude with ANITA. Comments on IceTop, the surface component of IceCube are also included.

astro-ph.HE↗

arXiv2012

Astrophysical neutrino results

This paper is a brief review of the status of the search for astrophysical neutrinos of high energy. Its emphasis is on the search for a hard spectrum of neutrinos from the whole Northern sky above the steeply falling background of atmospheric neutrinos. Current limits are so low that they are beginning to constrain models of the origin of extragalactic cosmic rays. Systematic effects stemming from incomplete knowledge of the background of atmospheric neutrinos are discussed.

astro-ph.HE↗

arXiv2011

IceCube: Status and Results

This talk describes the complete IceCube neutrino telescope and summarizes some results obtained while the detector was under construction.

astro-ph.HE↗

arXiv2011

Cosmic-ray physics with IceCube

IceCube as a three-dimensional air-shower array covers an energy range of the cosmic-ray spectrum from below 1 PeV to approximately 1 EeV. This talk is a brief review of the function and goals of IceTop, the surface component of the IceCube neutrino telescope. An overview of different and complementary ways that IceCube is sensitive to the primary cosmic-ray composition up to the EeV range is presented. Plans to obtain composition information in the threshold region of the detector in order to overlap with direct measurements of the primary composition in the 100-300 TeV range are also described.

astro-ph.IM↗

arXiv2011

Sibyll with charm

The cosmic ray interaction event generator Sibyll is widely used in extensive air shower simulations for cosmic ray and neutrino experiments. Charmed particle production has been added to the Monte Carlo with a phenomenological, non-perturbative model that properly accounts for charm production in the forward direction. As prompt decays of charm can become a significant background for neutrino detection, proper simulation of charmed particles is very important. We compare charmed meson and baryon production to accelerator data.

astro-ph.HE↗

arXiv2010

Cosmic rays: current status, historical context

The ISVHECRI conference series emphasizes the connection between high energy physics and cosmic ray physics--the study of elementary particles and nuclei from accelerators in the lab and from space. In this introductory paper on cosmic rays, I comment on several current topics in the field while also providing some historical context.

astro-ph.HE↗

arXiv2010

Seasonal variation of atmospheric leptons as a probe of charm

The intensity of TeV atmospheric muons and neutrinos depends on the temperature in the stratosphere. We show that the energy-dependence in the 100 TeV range of the correlation with temperature is sensitive to the fraction of muons and neutrinos from decay of charmed hadrons. We discuss the prospects for using the temperature effect as observed in gigaton neutrino detectors to measure the charm contribution.

astro-ph.HE↗

arXiv2010

Atmospheric neutrinos in the context of muon and neutrino radiography

Using the atmospheric neutrinos to probe the density profile of the Earth depends on knowing the angular distribution of the neutrinos at production and the neutrino cross section. This paper reviews the essential features of the angular distribution with emphasis on the relative contributions of pions, kaons and charm.

astro-ph.EP↗

arXiv2009

Cosmic ray event generator Sibyll 2.1

The cosmic ray interaction event generator Sibyll is widely used in extensive air shower simulations. We describe in detail the properties of Sibyll 2.1 and the differences with the original version 1.7. The major structural improvements are the possibility to have multiple soft interactions, introduction of new parton density functions, and an improved treatment of diffraction. Sibyll 2.1 gives better agreement with fixed target and collider data, especially for the inelastic cross sections and multiplicities of secondary particles. Shortcomings and suggestions for future improvements are also discussed.

hep-ph↗

arXiv2009

IceCube3--a new window on the Universe

This paper gives an overview of the scientific goals of IceCube with an emphasis on the importance of atmospheric neutrinos. Status and schedule for completing the detector are presented.

astro-ph.IM↗

arXiv2008

Vetoing atmospheric neutrinos in a high energy neutrino telescope

We discuss the possibility to suppress downward atmospheric neutrinos in a high energy neutrino telescope. This can be achieved by vetoing the muon which is produced by the same parent meson decaying in the atmosphere. In principle, atmospheric neutrinos with energies $E_ν> 10$ TeV and zenith angle up to 60 degree can be vetoed with an efficiency of > 99%. Practical realization will depend on the depth of the neutrino telescope, on the muon veto efficiency and on the ability to identify downward moving neutrinos with a good energy estimation.

astro-ph↗

arXiv2008

Muons and Neutrinos 2007

This paper is the written version of the rapporteur talk on Section HE-2, muons and neutrinos, presented at the 30th International Cosmic Ray Conference, Merida, Yucatan, July 11, 2007. Topics include atmospheric muons and neutrinos, solar neutrinos and astrophysical neutrinos as well as calculations and instrumentation related to these topics.

astro-ph↗

arXiv2008

RICAP-07: Summary comments

The Roma International Conference on Astroparticle Physics covered gamma-ray astronomy, air shower experiments and neutrino astronomy on three successive days. I organize my brief summary comments into four topics that cut across these three techniques. They are detector calibration, galactic sources, extra-galactic sources and cosmology.

astro-ph↗