Pat Bowe

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The ALPHA experiment aims to trap antihydrogen as the next crucial step towards a precise CPT test, by a spectroscopic comparison of antihydrogen with hydrogen. The experiment will retain the salient techniques developed by the ATHENA collaboration during the previous phase of antihydrogen experiments at the antiproton decelerator (AD) at CERN. The(More)
A theoretical underpinning of the standard model of fundamental particles and interactions is CPT invariance, which requires that the laws of physics be invariant under the combined discrete operations of charge conjugation, parity and time reversal. Antimatter, the existence of which was predicted by Dirac, can be used to test the CPT theorem-experimental(More)
We report the application of evaporative cooling to clouds of trapped antiprotons, resulting in plasmas with measured temperature as low as 9 K. We have modeled the evaporation process for charged particles using appropriate rate equations. Good agreement between experiment and theory is observed, permitting prediction of cooling efficiency in future(More)
The goal of the ALPHA collaboration at CERN is to test CPT conservation by comparing the 1S–2S transitions of hydrogen and antihydrogen. To reach the ultimate accuracy of 1 part in 10 18 , the (anti)atoms must be trapped. Using current technology, only magnetic minimum traps can confine (anti)hydrogen. In this paper, the design of the ALPHA antihydrogen(More)
The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom's stature lies in its simplicity and in the accuracy with which its spectrum can be measured and compared to theory. Today its(More)
We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a(More)
Control of the radial profile of trapped antiproton clouds is critical to trapping antihydrogen. We report the first detailed measurements of the radial manipulation of antiproton clouds, including areal density compressions by factors as large as ten, by manipulating spatially overlapped electron plasmas. We show detailed measurements of the near-axis(More)
We have demonstrated storage of plasmas of the charged constituents of the antihydrogen atom, antiprotons and positrons, in a Penning trap surrounded by a minimum-B magnetic trap designed for holding neutral antiatoms. The neutral trap comprises a superconducting octupole and two superconducting, solenoidal mirror coils. We have measured the storage(More)
A microchannel plate (MCP)/phosphor screen assembly has been used to destructively measure the radial profile of cold, confined antiprotons, electrons, and positrons in the ALPHA experiment, with the goal of using these trapped particles for antihydrogen creation and confinement. The response of the MCP to low energy (10-200 eV, <1 eV spread) antiproton(More)
We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen(More)