Anisotropy of the primary cosmic-ray flux in Super-Kamiokande

TL;DR

This study presents the first 2D celestial map of primary cosmic-ray flux using Super-Kamiokande data, revealing anisotropies with excess and deficit regions in Taurus and Virgo, respectively.

Contribution

It provides the first detailed 2D map of cosmic-ray anisotropy, highlighting specific celestial regions with flux excesses and deficits.

Findings

Detected a 0.104% excess in Taurus

Observed a -0.094% deficit toward Virgo

Mapped cosmic-ray anisotropy in celestial coordinates

Abstract

A first-ever 2-dimensional celestial map of primary cosmic-ray flux was obtained from 2.10x10^8 cosmic-ray muons accumulated in 1662.0 days of Super-Kamiokande. The celestial map indicates an (0.104 \pm 0.020)% excess region in the constellation of Taurus and a -(0.094 \pm 0.014)% deficit region toward Virgo. Interpretations of this anisotropy are discussed.