Tag: Publication
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ALPHA probes Antimatter Gravity
Physicists have long wondered if the gravitational interaction between antimatter and matter might be different than that between matter and itself. Do atoms made of antimatter, like antihydrogen, fall at a different rate to those made of matter, or might they even fall up – antigravity? There are many arguments that make the case that
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Description and first application of a new technique to measure the gravitational mass of antihydrogen
Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect indications that no such differences exist and that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. Here we describe
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Experimental and computational study of the injection of antiprotons into a positron plasma for antihydrogen production
One of the goals of synthesizing and trapping antihydrogen is to study the validity of charge-parity–time symmetry through precision spectroscopy on the anti-atoms, but the trapping yield achieved in recent experiments must be significantly improved before this can be realized. Antihydrogen atoms are commonly produced by mixing antiprotons and positrons stored in a nested Penning-Malmberg
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Antihydrogen formation by autoresonant excitation of antiproton plasmas
In efforts to trap antihydrogen, a key problem is the vast disparity between the neutral trap energy scale (∼ 50 μeV), and the energy scales associated with plasma confinement and space charge (∼ 1 eV). In order to merge charged particle species for direct recombination, the larger energy scale must be overcome in a manner
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Antihydrogen annihilation reconstruction with the ALPHA silicon detector
The ALPHA experiment has succeeded in trapping antihydrogen, a major milestone on the road to spectroscopic comparisons of antihydrogen with hydrogen. An annihilation vertex detector, which determines the time and position of antiproton annihilations, has been central to this achievement. This detector, an array of double-sided silicon microstrip detector modules arranged in three concentric cylindrical
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Alternative method for reconstruction of antihydrogen annihilation vertices
The ALPHA experiment, located at CERN, aims to compare the properties of antihydrogen atoms with those of hydrogen atoms. The neutral antihydrogen atoms are trapped using an octupole magnetic trap. The trap region is surrounded by a three layered silicon detector used to reconstruct the antiproton annihilation vertices. This paper describes a method we have
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Resonant quantum transitions in trapped antihydrogen atoms
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 1 and compared
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A new result from ALPHA – The first measurements of the Antihydrogen Spectrum
Once you've trapped antihydrogen what do you do? You measure it! That’s just what we’ve done. Published in Nature, we report the first resonant quantum transitions in antihydrogen atoms. We’ve used microwave radiation to change the internal state of the atom, from one which can be kept in our trap, to one that is kicked
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Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap
Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon
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The ALPHA detector: Module Production and Assembly
ALPHA is one of the experiments situated at CERN’s Antiproton Decelerator (AD). A Silicon Vertex Detector (SVD) is placed to surround the ALPHA atom trap. The main purpose of the SVD is to detect and locate antiproton annihilation events by means of the emitted charged pions. The SVD system is presented with special focus given