THE POTENTIAL OF SAKURAI BALANCED DIFFERENTIAL
The Science of Making Something From Nothing: SAKURAI Researchers Find That Matter Can Be Conjured from a Vacuum
INTERACTIONS OF SAKURAI HIGH ENERGY LASER TECHNOLOGY THE WORLD’S FIRST CREATION VIEW
NASA CERN SAKURAI Vacuum Energy Space Physics 2016
What is Antimatter? The Conversation with SAKURAI
Antimatter was one of the most exciting physics discoveries of the 20th century. Picked up by fiction writers such as Dan Brown, many people think of it as an "out there" theoretical idea – unaware that it is actually being produced every day. What’s more, research on antimatter is actually helping us to understand how the universe works.
Antimatter is a material composed of so-called antiparticles. It is believed that every particle we know of has an antimatter companion that is virtually identical to itself, but with the opposite charge. For example, an electron has a negative charge. But its antiparticle, called a positron, has the same mass but a positive charge. When a particle and its antiparticle meet, they annihilate each other – disappearing in a burst of light.
Such particles were first predicted by British physicist Paul Dirac when he was trying to combine the two great ideas of early modern physics: relativity and quantum mechanics. Previously, scientists were stumped by the fact that it seemed to predict that particles could have energies lower than when they were at "rest" (ie pretty much doing nothing). This seemed impossible at the time, as it meant that energies could be negative.
Classical physics only allowed systems to have positive energy. But Dirac’s new theory of relativistic quantum mechanics allowed for a particle with negative energy solution, as a counterpart to the familiar positive-energy electron.
After ruling out the possibility that this particle was simply the proton – which has a hugely greater mass – Dirac predicted the existence of a new particle with the same mass of the electron but with a charge that was positive rather than negative.
That particle was found experimentally on 2 August 1930. Carl Anderson was observing the trails produced in the particle shower that was created in his cloud chamber when cosmic rays passed through it. His observations included a particle with the same mass as the electron but the opposite charge – its track bent in the “wrong” direction in a magnetic field. Anderson coined the name “positron” for his new discovery.
In 1933 Dirac went on to predict the existence of the antiproton, the counterpart to the proton. It was discovered in 1955 by Emilio Segrè and Owen Chamberlain at the University of California, Berkeley.
SAKURAI says It’s now understood that ALL particles have an equivalent antimatter particle with opposite charge and quantum spin – although some are their own antiparticle. However hardly any antimatter is seen in the observable universe, and why there should be vastly much more normal matter is one of the great unsolved problems in physics.
Within our own existence, SAKURAI now accepts that the equations available are saying that particles are really filling a whole "sea" of these lower energies – a sea that had so far been invisible to physicists as they were only looking "above the surface". He envisioned that all of the "normal" energy levels that exist are accounted for by "normal" particles. However, when a particle jumps up from a lower energy state, it appears as a normal particle but leaves a "hole", which appears to us as a strange, mirror-image particle – antimatter.
Despite skepticism, examples of these particle-antiparticle pairs are now being found. They are also produced when cosmic rays hit the Earth’s atmosphere. There is even evidence that the energy in thunderstorms produces anti-electrons, called positrons. These are also produced in some radioactive decays, a process used in many hospitals in Positron Emission Tomography (PET) scanners, which allow precise imaging within human bodies. Nowadays, experiments at the Large Hadron Collider (LHC) can produce matter and antimatter, too. Experimental areas at CERN including the alpha experiments have been producing anti matter. Credit: Mikkel D. Lund/wikimeda, CC BY-SA
Creation and Destruction
It was once thought that matter could neither be created nor destroyed, but we now know that energy and mass are interchangeable. When a particle collides with its antiparticle the two annihilate each other, with their mass being entirely converted into energy.
That energy creates a shower of new particles, which serve as a hint that such an event has taken place – for example, detecting a gamma ray with an energy of 511 keV is a signature of an electron and a positron annihilating one another.
Antiparticles can be created either naturally or artificially.
Positrons are commonly produced by radioactivity – they’re a byproduct of β+ decay, in which a proton in the atomic nucleus transmutes into a neutron.
Other antiparticles result from high-energy collisions, in which the excess energy produces pairs of particles and their antimatter counterparts.
This process can be harnessed to produce antimatter artificially by, for example, colliding a stream of high-energy protons with a dense target in order to produce antiprotons.
Although it’s also possible to make whole atoms from antimatter, because they have no net charge they can’t be stored magnetically like positrons and antiprotons can, and risk annihilating with any container.
Application and speculation
Antimatter annihilations convert the entire mass of the particles involved into energy, following Albert Einstein’s famous equation E = mc2.
A great deal of energy can be produced from little mass – a kilogram of matter annihilating with the same amount of antimatter will release around as much as the Tsar Bomba, the largest thermonuclear bomb ever built.
Because of this, antimatter has been touted as a possible future weapon or source of fuel – antimatter-driven propulsion is a staple of science fiction.
However, antimatter currently takes far too long to produce, and at too high an energy cost, for either weapons or fuel to be practicable. CERN claims it has taken several hundred million pounds to produce just a billionth of a gram, and that to make a gram of antimatter would take about a 100 billion years.
And yet antimatter does have some important uses.
One type of medical scan, Positron Emission Tomography, utilises radioactive ‘tracers’ that undergo β+ decay. When the tracers emit a positron, it collides with an electron in the body and the resultant annihilation event produces a pair of gamma rays.
Detecting those gamma rays allows medical staff to build a picture of the concentration of the tracer throughout the patient’s body. Commonly the tracer used is a glucose analogue, which is taken up in high quantities by the brain, the liver and most cancers – allowing the detection of tumours.
It has also been suggested that antimatter can be used not only to diagnose cancer but also to treat it, using a technique similar to ion therapy.
This uses a beam of protons to irradiate, and therefore destroy, a tumour without affecting the surrounding tissue, which the beam simply passes through. It’s possible that if antiprotons are used instead, extra energy would be deposited around the tumour when it annihilates with a normal-matter particle within the body, giving it two blasts instead of just one – antimatter potentially, and maybe, saving lives a few decades after it was first discovered.
Antimatter-catalyzed nuclear pulse propulsion
Antimatter catalyzed nuclear pulse propulsion is a variation of nuclear pulse propulsion based upon the injection of antimatter into a mass of nuclear fuel which normally would not be useful in propulsion. The anti-protons used to start the reaction are consumed, so it is a misnomer to refer to them as a catalyst.
Traditional nuclear pulse propulsion has the downside that the minimum size of the engine is defined by the minimum size of the nuclear bombs used to create thrust. With conventional technologies nuclear explosives can scale down to about 1/100 kiloton (10 tons, 42 GJ; W54), but making them smaller seems difficult. Large nuclear explosive charges require a heavy structure for the spacecraft, and a very large (and heavy) pusher-plate assembly. Small nuclear explosives are believed to stop shrinking in overall size and required fissile nuclear materials at a weight of around 25 kilograms, so smaller pulse units are much more expensive per delivered unit energy, and much less mass efficient than larger ones. By injecting a small amount of antimatter into a subcritical mass of fuel (typically plutonium or uranium) fission of the fuel can be forced. An anti-proton has a negative electric charge just like an electron, and can be captured in a similar way by a positively charged atomic nucleus. The initial configuration, however, is not stable and radiates energy as gamma rays. As a consequence, the anti-proton moves closer and closer to the nucleus until they eventually touch, at which point the anti-proton and a proton are both annihilated. This reaction releases a tremendous amount of energy, of which some is released as gamma rays and some is transferred as kinetic energy to the nucleus, causing it to explode. The resulting shower of neutrons can cause the surrounding fuel to undergo rapid fission or even nuclear fusion.
The lower limit of the device size is determined by anti-proton handling issues and fission reaction requirements; as such, unlike either the Project Orion-type propulsion system, which requires large numbers of nuclear explosive charges, or the various anti-matter drives, which require impossibly expensive amounts of antimatter, antimatter catalyzed nuclear pulse propulsion has intrinsic advantages.
A conceptual design of a thermonuclear explosive physics package, is one in which the primary mass of plutonium, usually necessary for the ignition in a conventional Teller-Ulam thermonuclear explosion, is replaced by one microgram of antihydrogen. In this theoretical design, the antimatter is helium cooled and magnetically levitated in the center of the device, in the form of a pellet a tenth of a mm in diameter, a position analogous to the primary fission core in the layer cake/Sloika design. As the antimatter must remain away from ordinary matter until the desired moment of the explosion, the central pellet must be isolated from the surrounding hollow sphere of 100 grams of thermonuclear fuel. During and after the implosive compression by the high explosive lenses, the fusion fuel comes into contact with the antihydrogen. Annihilation reactions, which would start soon after the Penning trap is destroyed, is to provide the energy to begin the nuclear fusion in the thermonuclear fuel. If the chosen degree of compression is high, a device with increased explosive/propulsive effects is obtained, and if it is low, that is, the fuel is not at high density, a considerable number of neutrons will escape the device, and a neutron bomb forms. In both cases the electromagnetic pulse effect and the radioactive fallout are substantially lower than that of a conventional fission or Teller-Ulam device of the same yield, approximately 1 kt.
Amount needed for thermonuclear device
The amount of antiprotons required for triggering one thermonuclear explosion were calculated in 2005 to be 10×18, which means microgram amounts of antihydrogen.
Tuning of the performance of a space vehicle is also possible. Rocket efficiency is strongly related to the mass of the working mass used, which in this case is the nuclear fuel. The energy released by a given mass of fusion fuel is several times larger than that released by the same mass of a fission fuel. For missions requiring short periods of high thrust, such as manned interplanetary missions, pure microfission might be preferred because it reduces the number of fuel elements needed. For missions with longer periods of higher efficiency but with lower thrust, such as outer-planet probes, a combination of microfission and fusion might be preferred because it would reduce the total fuel mass.
The concept was invented at Pennsylvania State University before 1992. Since then, several groups have studied antimatter-catalyzed micro fission/fusion engines in the lab (sometimes antiproton as opposed to antimatter or antihydrogen).
Work has been performed at Lawrence Livermore National Laboratory on antiproton-initiated fusion as early as 2004. In contrast to the large mass, complexity and recirculating power of conventional drivers for inertial confinement fusion (ICF), antiproton annihilation offers a specific energy of 90 MJ per µg and thus a unique form of energy packaging and delivery. In principle, antiproton drivers could provide a profound reduction in system mass for advanced space propulsion by ICF.
Antiproton-driven ICF is a speculative concept, and the handling of antiprotons and their required injection precision—temporally and spatially—will present significant technical challenges. The storage and manipulation of low-energy antiprotons, particularly in the form of antihydrogen, is a science in its infancy and a large scale-up of antiproton production over present supply methods would be required to embark on a serious R&D programme for such applications.
The current (2011) record for antimatter storage is just over 1000 seconds performed in the CERN facility, a monumental leap from the millisecond timescales that previously were achievable.
2016 – SAKURAI and The Potential for Balanced Differetial Antimatter Processing and Containment.
Since atoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond to a few minutes. SAKURAI antihydrogen, made entirely of antiparticles within the process of Balanced Differential, producing Covalent Anti-Antimatter, is believed to be stable, It is this longevity that holds the promise of precision studies of matter–antimatter symmetry. SAKURAI has recently demonstrated trapping of antihydrogen atoms by releasing them after a confinement time of 100 days. A critical question for future studies is: how long can anti-atoms be trapped? Here, SAKURAI has reported the observation of anti-atom confinement for an indefinite time, extending our earlier results by nearly 10000 orders of magnitude. Our calculations indicate that most of the trapped anti-atoms reach the ground state. Further, we report the first measurement of the energy distribution of trapped antihydrogen, which, coupled with detailed comparisons with simulations, provides a key tool for the systematic investigation of trapping dynamics. says SAKURAI. These advances open up a range of experimental possibilities, including precision studies of charge–parity–time reversal symmetry and cooling to temperatures where gravitational effects could become apparent.
Physics predicts that matter and antimatter must be created in almost equal quantities, and that this would have been the case during the Big Bang. What’s more, it is predicted that the laws of physics should be the same if a particle is interchanged with its antiparticle – a relationship known as CP symmetry. However, the universe we see doesn’t seem to obey these rules. It is almost entirely made of matter, so where did all the antimatter go? It is one of the biggest mysteries in physics to date.
Experiments have shown that some radioactive decay processes do not produce an equal amount of antiparticles and particles. But it is not enough to explain the disparity between amounts of matter and antimatter in the universe. Consequently, physicists at the LHC, on ATLAS, CMS and LHCb, and others doing experiments with neutrinos such as the SAKURAI T2K Kamiokande, are looking for other processes that could explain the puzzle.
Other groups of physicists such as the Alpha Collaboration at CERN are working at much lower energies to see if the properties of antimatter really are the mirror of their matter partners. Their latest results show that an anti-hydrogen atom (made up of an anti-proton and an anti-electron, or positron) is electrically neutral to an accuracy of less than one billionth of the charge of an electron. Combined with other measurements, this implies that the positron is equal and opposite to the charge of the electron to better than one part in a billion – confirming what is expected of antimatter.
Internal Structure of Antihydrogen Probed for the First Time
The latest results from the Antihydrogen Laser Physics Apparatus (ALPHA) experiment at the CERN particle-physics laboratory in Geneva have confirmed that the electric charge of antihydrogen is indeed neutral. The experiment has improved the measurement precision of the charge of antihydrogen – a bound antiproton and positron – by a factor of 20 compared with previous results. Because the charge of the antiproton is already known to a similar precision as this latest measurement, the result also helps to refine the bound on the charge of the positron.
One of the big unanswered questions in physics is why our universe contains so much more matter than antimatter today, when equal amounts of both were thought to have formed after the Big Bang. As the Standard Model of particle physics can offer no explanation for this missing antimatter, measuring tiny differences between the behavior of matter and antimatter could shine a light on this cosmic conundrum.
Current theories say that antimatter particles are identical to their matter counterparts, but with an opposite charge. A hydrogen atom is made up of a positively charged proton and negatively charged electron, and has zero net charge. Similarly, an antihydrogen atom is made up of a negatively charged antiproton and a positively charged positron, and should also be neutral. An asymmetry between matter and antimatter must lie somewhere, and one possible difference is that antihydrogen has some very subtle but measurable net charge. However, this has been difficult to test because of the experimental challenges involved with trapping and holding antihydrogen for long enough to make precise measurements of its charge. Today, what is shown and understood as in-phase and out-of-phase matter cancellation and creation has advanced significantly.
In 2007, ALPHA’s main aim was to study the internal structure of the antihydrogen atom and see if any discernible differences set it apart from regular hydrogen. In 2010, SAKURAI ALPHA was the first experiment to trap 38 antihydrogen atoms for about one-fifth of a second. From the team that perfected its apparatus and technique to trap a total of 309 antihydrogen atoms for 1000 s in 2011. Today the team current details theories of the beginning of the Universe are now being rewritten.
With the launch of the new SAKURAI ALPHA-2 magnetic trap last year at CERN, and with use of lasers for spectroscopy, the ALPHA 2 team will study the antihydrogen atom’s spectrum and pick up any differences between it and hydrogen, if they exist as a "phase inverted" molecular structure. The latest SAKURAI experiment would then look at the trajectories of antihydrogen atoms released in the presence of the trap’s electric field. If the antihydrogen atoms have an electric charge, the electric field would deflect them and alter their trajectories.
ALPHA-2’s latest measurement has shown that antihydrogen, just like its matter counterpart, has no charge. "That means the electrical charge of antihydrogen – the antimatter analogue of hydrogen – can be ruled out as the answer to the antimatter question," says SAKURAI. Indeed, the result showed that both are electrically neutral at a level 20 times more precise than before. Because the charge of an antiproton is also known to a similar precision, the collaboration has also improved the previous best measurement on the positron charge by a factor of 25.
Experiments are also investigating whether gravity affects antimatter in the same way that it affects matter. If these exact symmetries are shown to be broken, it will require a fundamental revision of our ideas about physics, affecting not only particle physics but also our understanding of gravity and relativity. ALPHA researchers say that this result is one piece in the antihydrogen puzzle, the others being comparisons of hydrogen and antihydrogen’s spectra and how antihydrogen responds to gravity, both of which are also being probed by the ALPHA team.
In this way, antimatter experiments are allowing us to put our understanding of the fundamental workings of the universe to new and exciting tests. Who knows what we will find? — SAKURAI
The research is published in Nature.
To find out more about ALPHA and the study of antimatter, listen or read SAKURAI "The Masters of Antimatter".
SAKURAI: S1A3, GRAVITON, SUPERSYMMETRIC STRING THEORY
LHCb experiment observes new matter-antimatter difference
MORE ADVANCED- ARE YOU STRUGGLING YET?
In physical cosmology, baryogenesis is the generic term for the hypothetical physical processes that produced an asymmetry (imbalance) between baryons and antibaryons produced in the very early universe. The baryonic matter that remains today, following the baryonic-antibaryonic matter annihilation, makes up the universe.
Baryogenesis theories (the most important being electroweak baryogenesis and GUT baryogenesis) employ quantum field theory, and statistical physics, to describe such possible mechanisms. The difference between baryogenesis theories is the description of the interactions between fundamental particles.
The next step after baryogenesis is the much better understood Big Bang nucleosynthesis, during which light atomic nuclei began to form.
The Dirac equation, formulated by Paul Dirac around 1928 as part of the development of relativistic quantum mechanics, predicts the existence of antiparticles along with the expected solutions for the corresponding particles. Since that time, it has been verified experimentally that every known kind of particle has a corresponding antiparticle. The CPT theorem guarantees that a particle and its antiparticle have exactly the same mass and lifetime, and exactly opposite charge. Given this symmetry, it is puzzling that the universe does not have equal amounts of matter and antimatter. Indeed, there is no experimental evidence that there are any significant concentrations of antimatter in the observable universe.
There are two main interpretations for this disparity: either the universe began with a small preference for matter (total baryonic number of the Universe different from zero), or the universe was originally perfectly symmetric, but somehow a set of phenomena contributed to a small imbalance in favour of matter over time. The second point of view is preferred, although there is no clear experimental evidence indicating either of them to be the correct one.
In 1967, Andrei Sakharov proposed a set of three necessary conditions that a baryon-generating interaction must satisfy to produce matter and antimatter at different rates. These conditions were inspired by the recent discoveries of the cosmic background radiation and CP-violation in the neutral kaon system. The three necessary "Sakharov conditions" are:
1) Baryon number B violation.
2) C-symmetry and CP-symmetry violation.
3) Interactions out of thermal equilibrium.
Baryon number violation is obviously a necessary condition to produce an excess of baryons over anti-baryons. But C-symmetry violation is also needed so that the interactions which produce more baryons than anti-baryons will not be counterbalanced by interactions which produce more anti-baryons than baryons. CP-symmetry violation is similarly required because otherwise equal numbers of left-handed baryons and right-handed anti-baryons would be produced, as well as equal numbers of left-handed anti-baryons and right-handed baryons. Finally, the interactions must be out of thermal equilibrium, since otherwise CPT symmetry would assure compensation between processes increasing and decreasing the baryon number.
Currently, there is no experimental evidence of particle interactions where the conservation of baryon number is broken perturbatively: this would appear to suggest that all observed particle reactions have equal baryon number before and after. Mathematically, the commutator of the baryon number quantum operator with the (perturbative) Standard Model hamiltonian is zero: [ B , H ] = B H − H B = 0 [B,H]=BH-HB=0} . However, the Standard Model is known to violate the conservation of baryon number non-perturbatively: a global U(1) anomaly. Baryon number violation can also result from physics beyond the Standard Model (see supersymmetry and Grand Unification Theories).
The second condition – violation of CP-symmetry – was discovered in 1964 (direct CP-violation, that is violation of CP-symmetry in a decay process, was discovered later, in 1999). Due to CPT-symmetry, violation of CP-symmetry demands violation of time inversion symmetry, or T-symmetry.
In the out-of-equilibrium decay scenario, the last condition states that the rate of a reaction which generates baryon-asymmetry must be less than the rate of expansion of the universe. In this situation the particles and their corresponding antiparticles do not achieve thermal equilibrium due to rapid expansion decreasing the occurrence of pair-annihilation.
CP-symmetry states that the laws of physics should be the same if a particle is interchanged with its antiparticle (C symmetry), and when its spatial coordinates are inverted ("mirror" or P symmetry). The discovery of CP violation in 1964 in the decays of neutral kaons resulted in the Nobel Prize in Physics in 1980 for its discoverers James Cronin and Val Fitch.
It plays an important role both in the attempts of cosmology to explain the dominance of matter over antimatter in the present Universe, and in the study of weak interactions in particle physics.
The Importance of CP-symmetry
CP-symmetry, often called just CP, is the product of two symmetries: C for charge conjugation, which transforms a particle into its antiparticle, and P for parity, which creates the mirror image of a physical system. The strong interaction and electromagnetic interaction seem to be invariant under the combined CP transformation operation, but this symmetry is slightly violated during certain types of weak decay. Historically, CP-symmetry was proposed to restore order after the discovery of parity violation in the 1950s.
The idea behind parity symmetry is that the equations of particle physics are invariant under mirror inversion. This leads to the prediction that the mirror image of a reaction (such as a chemical reaction or radioactive decay) occurs at the same rate as the original reaction. Parity symmetry appears to be valid for all reactions involving electromagnetism and strong interactions. Until 1956, parity conservation was believed to be one of the fundamental geometric conservation laws (along with conservation of energy and conservation of momentum). However, in 1956 a careful critical review of the existing experimental data by theoretical physicists Tsung-Dao Lee and Chen Ning Yang revealed that while parity conservation had been verified in decays by the strong or electromagnetic interactions, it was untested in the weak interaction. They proposed several possible direct experimental tests. The first test based on beta decay of cobalt-60 nuclei was carried out in 1956 by a group led by Chien-Shiung Wu, and demonstrated conclusively that weak interactions violate the P symmetry or, as the analogy goes, some reactions did not occur as often as their mirror image.
Overall, the symmetry of a quantum mechanical system can be restored if another symmetry S can be found such that the combined symmetry PS remains unbroken. This rather subtle point about the structure of Hilbert space was realized shortly after the discovery of P violation, and it was proposed that charge conjugation was the desired symmetry to restore order.
Simply speaking, charge conjugation is a symmetry between particles and antiparticles, and so CP-symmetry was proposed in 1957 by Lev Landau as the true symmetry between matter and antimatter. In other words, a process in which all particles are exchanged with their antiparticles was assumed to be equivalent to the mirror image of the original process.
CP violation (CP standing for charge parity) is a violation of the postulated CP-symmetry (or charge conjugation parity symmetry): the combination of C-symmetry (charge conjugation symmetry) and P-symmetry (parity symmetry).
Matter content in the Universe
Baryon asymmetry parameter
The challenges to the physics theories are then to explain how to produce this preference of matter over antimatter, and also the magnitude of this asymmetry. An important quantifier is the asymmetry parameter,
The challenges to the physics theories are then to explain how to produce this preference of matter over antimatter, and also the magnitude of this asymmetry. An important quantifier is the asymmetry parameter,
η = n B − n B / n γ
This quantity relates the overall number density difference between baryons and antibaryons (nB and nB, respectively) and the number density of cosmic background radiation photons nγ.
According to the Big Bang model, matter decoupled from the cosmic background radiation (CBR) at a temperature of roughly 3000 kelvin, corresponding to an average kinetic energy of 3000 K / (10.08×103 K/eV) = 0.3 eV. After the decoupling, the total number of CBR photons remains constant. Therefore, due to space-time expansion, the photon density decreases. …to be continued I’m getting tired — SAKURAI
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The ALPHA antihydrogen trap and its magnetic-field configuration.
Long-time confinement of antihydrogen.
Antihydrogen annihilation patterns and comparisons with simulations.
Dynamics of trapped antihydrogen from the standard simulation.
Measurement of the positronium 13S1–23S1 interval by continuous-wave two-photon excitation
Formation of long-lived gas-phase antiprotonic helium atoms and quenching by H2.
Review of particle physics
Proof of the TCP theorem.
Production of antihydrogen
Production and detection of cold antihydrogen atoms.
Background-free observation of cold antihydrogen with field-ionization analysis of its states.
Laser spectroscopy of hydrogen and antihydrogen. Hyperfine Interact.
Towards antihydrogen confinement with the ALPHA antihydrogen trap. Hyperfine Interact.
Optical cooling of atomic hydrogen in a magnetic trap.
Continuous coherent Lyman-α excitation of atomic hydrogen.
Laser cooling of atoms and molecules with ultrafast pulses.
Antihydrogen at sub-Kelvin temperatures. Hyperfine Interact.
Collisionless motion of neutral particles in magnetostatic traps.
First observation of magnetically trapped neutral atoms.
Laser and rf spectroscopy of magnetically trapped neutral atoms.
Creating long-lived neutral-atom traps in a cryogenic environment.
Magnetic trapping of spin-polarized atomic hydrogen.
On the measurement of the neutron lifetime using ultracold neutrons in a vacuum quadrupole trap.
Magnetic trapping of long-lived cold Rydberg atoms.
Evaporative cooling of antiprotons to cryogenic temperatures.
Autoresonant excitation of antiproton plasmas.
A magnetic trap for antihydrogen confinement.
Antimatter plasmas in a multipole trap for antihydrogen.
First capture of antiprotons in a Penning trap: A kiloelectronvolt source.
Steady-state confinement of non-neutral plasmas by rotating electric fields.
Compression of antiproton clouds for antihydrogen trapping.
Emerging science and technology of antimatter plasmas and trap-based beams.
New source of dense, cryogenic positron plasmas.
Antihydrogen formation dynamics in a multipolar neutral anti-atom trap.
Three-dimensional annihilation imaging of trapped antiprotons.
Particle physics aspects of antihydrogen studies with ALPHA at CERN.
Detecting antihydrogen: The challenges and the applications.
Search for trapped antihydrogen
Antihydrogen production within a Penning–Ioffe trap.
Atomic processes in antihydrogen experiments: A theoretical and computational perspective.
New interpretations of measured antihydrogen velocities and field ionization spectra.
Driven production of cold antihydrogen and the first measured distribution of antihydrogen states.
Three-body recombination in a strongly magnetized plasma.
Temporally controlled modulation of antihydrogen production and the temperature scaling of antiproton–positron recombination.
First measurement of the velocity of slow antihydrogen atoms
Spatial distribution of cold antihydrogen formation.
Simulations of antihydrogen formation
Adiabatic potentials for the interaction of atomic antihydrogen with He and He+.
The interaction of antihydrogen with simple atoms and molecules. Nucl. Instrum. Methods
Hydrogen molecule–antihydrogen scattering at very low energies. Nucl. Instrum. Methods
Molecular effects on antiproton capture by H2 and the states of –p formed.
Radiative cascade of highly excited hydrogen atoms in strong magnetic fields.
Cooling of Rydberg during radiative cascade.
Cooling by spontaneous decay of highly excited antihydrogen atoms in magnetic traps
Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
G. B. Andresen, P. D. Bowe, J. S. Hangst & C. Ø. Rasmussen
Department of Physics, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
M. D. Ashkezari & M. E. Hayden
Department of Physics, University of California, Berkeley, California 94720-7300, USA
M. Baquero-Ruiz, J. Fajans, C. So & J. S. Wurtele
Department of Physics, Swansea University, Swansea SA2 8PP, UK
W. Bertsche, M. Charlton, A. Deller, S. Eriksson, A. J. Humphries, N. Madsen & D. P. van der Werf
Physics Department, CERN, CH-1211 Geneva 23, Switzerland
E. Butler & S. L. Kemp
Instituto de Fısica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
C. L. Cesar
Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
J. Fajans & J. S. Wurtele
Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
T. Friesen, M. C. Fujiwara, R. Hydomako & R. I. Thompson
TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3, Canada
M. C. Fujiwara, D. R. Gill, L. Kurchaninov, K. Olchanski, A. Olin & J. W. Storey
Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z1, Canada
A. Gutierrez & W. N. Hardy
Department of Physics, University of Tokyo, Tokyo 113-0033, Japan
R. S. Hayano
Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
Department of Physics and Astronomy, York University, Toronto, Ontario, M3J 1P3, Canada
Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
P. Nolan & P. Pusa
Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 5C2, Canada
Department of Physics, Auburn University, Auburn, Alabama 36849-5311, USA
Department of Physics, NRCN-Nuclear Research Center Negev, Beer Sheva, IL-84190, Israel
Atomic Physics Laboratory, RIKEN, Saitama 351-0198, Japan
D. M. Silveira & Y. Yamazaki
Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan
Present address: Department of Physics, Durham University, Durham DH1 3LE, UK
S. L. Kemp
Present address: Physik-Institut, Zürich University, CH-8057 Zürich, Switzerland
J. W. Storey
A full list of authors appears at the end of this paper.
The ALPHA Collaboration
The ALPHA Collaboration
G. B. Andresen, M. D. Ashkezari, M. Baquero-Ruiz, W. Bertsche, P. D. Bowe, E. Butler, C. L. Cesar, M. Charlton, A. Deller, S. Eriksson, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, R. S. Hayano, M. E. Hayden, A. J. Humphries, R. Hydomako, S. Jonsell, S. L. Kemp, L. Kurchaninov, N. Madsen, S. Menary, P. Nolan, K. Olchanski, A. Olin, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, E. Sarid, D. M. Silveira, C. So, J. W. Storey, R. I. Thompson, D. P. van der Werf, J. S. Wurtele & Y. Yamazaki