Material Type  

 학위논문

 

0017161894

Date and Time of Latest Transaction  

20250211151459

ISBN  

9798384453437

DDC  

530

Author  

Lyu, Yang.

Title/Author  

Probing the PeV Astrophysical Neutrino Spectral Cutoff Using Downgoing Tracks at IceCube.

Publish Info  

[S.l.] : University of California, Berkeley., 2024

Publish Info  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Material Info  

187 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: B.

General Note  

Advisor: Klein, Spencer R.;Shapiro, Marjorie D.

학위논문주기  

Thesis (Ph.D.)--University of California, Berkeley, 2024.

Abstracts/Etc  

요약IceCube has observed a diffuse astrophysical neutrino flux from ∼100 TeV to a few PeV, with an energy spectrum consistent with a single power law (SPL). In the PeV region, the spectral shape has not been precisely measured: starting track and cascade searches have a relatively small effective volume, upgoing tracks are mostly absorbed by the Earth, while the Extremely High Energy (EHE) analyses target cosmogenic neutrinos above 10 PeV. This analysis fills the gap between 1 PeV and 10 PeV by selecting high-energy down-going, through-going tracks. To reject the large atmospheric muon background, two largely complementary techniques are combined. The first technique selects events with high stochasticity to reject atmospheric muon bundles whose stochastic energy losses are smoothed due to high muon multiplicity. The second technique vetoes atmospheric muons with the IceTop surface array. Using 9 years of data, we found two events in the signal region, each with relatively high signal probabilities. A joint maximum likelihood estimation is performed using this sample with the previous 9.5-year upgoing track sample to measure the neutrino spectrum, and a likelihood ratio test is performed for the single power-law (SPL) vs. SPL+cutoff hypothesis. The best-fit cutoff energy is 1.83+6.92 −0.81 PeV. The p-value of the likelihood ratio test is 0.62, and the SPL+cutoff model is not significant over SPL. High-energy astrophysical objects from four source catalogs are also searched for around the direction of the two events. A BL Lac object is found inside the 90% directional uncertainty region of one event, while the second event does not have any associated objects.

Subject Added Entry-Topical Term  

Physics.

Subject Added Entry-Topical Term  

Particle physics.

Subject Added Entry-Topical Term  

Astrophysics.

Subject Added Entry-Topical Term  

Atmospheric sciences.

Index Term-Uncontrolled  

IceCube

Index Term-Uncontrolled  

Single power law

Index Term-Uncontrolled  

Spectral shape

Index Term-Uncontrolled  

Neutrino spectrum

Index Term-Uncontrolled  

Atmospheric muons

Added Entry-Corporate Name  

University of California, Berkeley Physics

Host Item Entry  

Dissertations Abstracts International. 86-03B.

Electronic Location and Access  

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Control Number  

joongbu:656479