Tag: Publication
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Be+-Assisted Antihydrogen Synthesis and Trapping
Be+-Assisted Antihydrogen Synthesis and Trapping Theses Antihydrogen, the bound state of a positron and an antiproton, is a uniquely well-suited system for testing fundamental symmetries between matter and antimatter. The Antihydrogen Laser Physics Apparatus (ALPHA collaboration) synthesises antihydrogen atoms by slowly merging cold non-neutral positron and antiproton plasmas and traps the antiatoms in a magnetic
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Be+ assisted, simultaneous confinement of more than 15000 antihydrogen atoms
Antihydrogen, the bound state of a positron and an antiproton, is the only pure anti-atomic system ever studied. It is produced exclusively in the laboratory, as it has never been observed in nature. This unique system is of great interest for searching for tentative differences between matter and antimatter. Anti-hydrogen has been routinely trapped since
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Detecting antihydrogen annihilations in ALPHA-g for measurement of gravitational free fall
Antihydrogen, the bound state of an antiproton and a positron, is an ideal system for testing fundamental symmetries between matter and antimatter. The Antihydrogen Laser PHysics Apparatus (ALPHA) at CERN has a proven history of producing and trapping antihydrogen atoms, with many precision tests of charge-parity-time (CPT) symmetry. The new ALPHA-g apparatus extends this program
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Evaluation of a caesium fountain frequency standard for antihydrogen spectroscopy
The performance of a caesium fountain frequency reference for use in precision measurements of trapped antihydrogen in the ALPHA experiment at CERN is evaluated. A description of the fountain is provided together with a characterisation of systematic effects. The impact of the magnetic environment in the Antimatter Factory, where the fountain is installed, on the
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Machine Learning Methods for Antihydrogen Detection
Antihydrogen, composing an antiproton and positron, is the only bound state of two antiparticles yet to be synthesised, making for an enticing system to study the purported symmetry of matter and antimatter. As antihydrogen does not occur naturally in the observable universe, any study of this atom requires it to be synthesised in a lab,
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The ALPHA-2 apparatus – facilitating experimentation with trapped antihydrogen
This paper describes the ALPHA-2 apparatus, used at the CERN Antiproton Decelerator facility for the study of trapped antihydrogen atoms. Details of both the construction and performance are included. Prominence is given to both the new and the improved features, with respect to the original ALPHA assembly, of the apparatus including a stand-alone antiproton catching
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Precision spectroscopy of the hyperfine components of the 1S–2S transition in antihydrogen
The antimatter equivalent of atomic hydrogen—antihydrogen—is an outstanding testbed for precision studies of matter–antimatter symmetry. Here we report on the simultaneous observation of both accessible hyperfine components of the 1S–2S transition in trapped antihydrogen. We determine the 2S hyperfine splitting in antihydrogen and—by comparing our results with those obtained in hydrogen—constrain the charge–parity–time-reversal symmetry-violating coefficients
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First Measurement of Antihydrogen Free Fall Using a Radial Time Projection Chamber
Using antihydrogen, an apparatus known as ALPHA-g was designed to test Einstein’s Weak Equivalence Principle (WEP), where the acceleration due to gravity that a body experiences is independent of its structure or composition. A measurement of the gravitational mass of antimatter has never been done before, as previous experiments used charged particles, which meant the
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Shot-noise-induced lower temperature limit of the nonneutral plasma parallel temperature diagnostic
We develop a new algorithm to estimate the temperature of a nonneutral plasma in a Penning-Malmberg trap. The algorithm analyzes data obtained by slowly lowering a voltage that confines one end of the plasma and collecting escaping charges, and is a maximum likelihood estimator based on a physically-motivated model of the escape protocol presented in
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Magnetic Field Characterisation for Gravitational Free Fall Measurements of Antihydrogen in the ALPHA-g Experiment
The bound state of an antiproton and positron, antihydrogen, is an ideal test particle for comparisons between matter and antimatter as hydrogen has been studied extensively through history both experimentally and theoretically. The Antihydrogen Laser Physics Apparatus (ALPHA) collaboration has made significant progress on antihydrogen trapping, cooling, and spectroscopy in recent years.In a new apparatus,