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Daniel P. Watts

Publications and source records attributed to Daniel P. Watts.

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Chemically-polarized material for nuclear and particle physics

Spin-polarized solid targets have underpinned many recent key advances in nuclear and particle physics, yet traditional methods to produce them face significant limitations due to the high cost and demanding cryogenic and magnetic field requirements. These factors constrain experimental geometries and present challenges in intense radiation environments where depolarization and materials damage can occur. We present the first results assessing the capabilities of the chemical hyperpolarization (ChHP) method Signal Amplification By Reversible Exchange (SABRE) to act as the polarization method to produce targets or active detector media. We show by using in-beam measurements that there is no depolarizing effect observed with the SABRE-polarized material in the A2 photon beam at the Mainzer Mikrotron (MAMI), as well as showing the resilience of such media to radioactive doses of up to \SI{3}{\kilo\gray}. We also illustrate the capabilities for using SABRE-polarized material as a scintillation or Cherenkov detector.

physics.ins-det

First Detailed Study of the Quantum Decoherence of Entangled Gamma Photons

Constraints on the quantum decoherence of entangled $γ$ quanta at the mega-electron-volt scale, such as those produced following positron annihilation, have remained elusive for many decades. We present the first statistically and kinematically precise experimental data for triple Compton scattering of such entangled $γ$. An entanglement witness ($R$), relating to the enhancement of the azimuthal correlation between the final scattering planes, is obtained where one of the $γ$ underwent intermediate Compton scattering. The measured $R$, deconvolved from multiple scattering backgrounds, are found to exceed the classical limit for intermediate scatter angles up to $\sim$60$^{\circ}$ and diminish at larger angles. The data are consistent with predictions from a first quantum theory of entangled triple Compton scattering as well as a simple model based approach. The results are crucial to future study and utilisation of entangled mega-electron-volt $γ$ in fundamental physics and PET imaging.

quant-ph