Particle.news
Download on the App Store
8 ARTICLES
·
8h ago

Joint NOvA–T2K Analysis Hints at Neutrino CP Violation in Nature Study

A combined cross-experiment result indicates a neutrino–antineutrino oscillation asymmetry relevant to the matter–antimatter puzzle.

Image
Image
The world’s first neutrino observation in a hydrogen bubble chamber. It was found November 13, 1970, on this photograph from the Zero Gradient Synchrotron’s 12-foot bubble chamber. The invisible neutrino strikes a proton where three particle tracks originate (lower right). The neutrino turns into a mu-meson, the long center track (extending up and left). The short track is the proton. The third track (extending down and left) is a pi-meson created by the collision. Image credit: Argonne National Laboratory.
Image

Overview

  • The NOvA and T2K collaborations published a first-of-its-kind joint oscillation analysis in Nature, pooling long-baseline accelerator data to boost precision.
  • The study reports an imbalance between neutrino and antineutrino oscillations, offering a suggestive sign of charge–parity symmetry violation.
  • Researchers emphasize the result is not yet definitive because of limited event counts and unresolved questions such as the neutrino mass ordering.
  • Complementary setups underpin the gain in sensitivity: NOvA sends a beam 810 km to a 14,000-ton far detector in Ash River, while T2K sends a shorter 295 km beam to Super-Kamiokande.
  • Event detection remains exceptionally rare and challenging, with heavy natural backgrounds and roughly one accelerator neutrino captured per day in NOvA’s far detector.