Measurement of the $\vec{n}p \to d\pi^0\pi^0$ Reaction with Polarized Beam in the Region of the $d^*(2380)$ Resonance

TL;DR

This study measures the neutron-proton to deuteron and two neutral pions reaction using polarized beams to investigate the $d^*(2380)$ resonance, confirming previous unpolarized results and revealing analyzing powers.

Contribution

It provides the first high-statistics polarized measurement of the reaction in the $d^*(2380)$ region, enhancing understanding of the resonance's properties.

Findings

Substantial analyzing powers observed.

Confirmation of the $d^*$ resonance from polarized data.

Agreement with previous unpolarized measurements.

Abstract

We report on a high-statistics measurement of the most basic double pionic fusion reaction $\vec{n}p \to d\pi^0\pi^0$ over the energy region of the $d^*(2380)$ resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the $d^*$ resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.