Antihydrogen Physics
Lead Research Organisation:
Swansea University
Department Name: College of Science
Abstract
Antihydrogen, the bound state of a positron and an antiproton, has recently been created under controlled conditions in the laboratory. The proposal seeks to exploit this advance by facilitating a new generation of experiments on antihydrogen held in a neutral trap, a so-called magnetic gradient trap. This is an arrangement of magnetic fields that acts upon the small magnetic moment of the anti-atom to produce a trapping force. However, such traps are shallow, and are currently only capable of holding antihydrogen in its ground state with kinetic energies equivalent to a temperature below 1 Kelvin. Thus, we need form antihydrogen with these low kinetic energies, a task not yet achieved. Once trapped, we hope to be able to do experiments to manipulate the antihydrogen, using electric and laser fields. Further into the future we hope to be able to produce very cold antihydrogen to make it possible to measure the gravitational interaction of antimatter. However, all experiments with antihydrogen are difficult, so the question we address here is; why bother? We will explain this using the example of symmetry.It has been apparent for a while that fundamental asymmetries are hidden deep within nature. For example, in the 1950's it was discovered that the weak nuclear interaction violates parity conservation. However, the defective parity mirror can be mostly repaired by adding so-called charge conjugation, which, loosely speaking, means that interactions are unaffected when every particle is substituted by its antiparticle. For a while it was believed that the laws of nature would obey the combination of parity reversal and charge conjugation. But by the mid-1960's this was found to be untrue for a small class of reactions involving unusual, fleeting, particles called K-mesons. Since then it has been assumed that the small blemish in the combined charge conjugation/parity reversal mirror can be corrected by the application of time-reversal.However, this 3-way switch differs from the three discrete symmetries, or any 2-way combination of them because the charge/parity/time combination exists as a theorem that can be proved using the basic postulates of quantum field theory. Such theories are the cornerstone of our current understanding of the Universe, but are widely recognised as being incomplete. So testing this unique 3-way switch is going to the heart of our understanding of nature. Our current picture of the beginning of the Universe involves the Big Bang, which is thought to have been an energetic event that created equal amounts of matter and antimatter. Why then did they not all annihilate one another and leave a Universe devoid of matter? Searches for large amounts of remnant antimatter in the Universe have, thus far, failed to find any trace. Currently it is thought that our Universe is matter dominant; in other words asymmetric. The other fact to add to this is that the amount of asymmetry we can currently identify via numerous studies of fleeting and rare particles isn't enough to explain the existence of the material Universe.Thus, it is only by probing the most basic symmetries that we can begin to understand how the Universe we observe came to be.
People |
ORCID iD |
Mike Charlton (Principal Investigator) |
Publications
Ahmadi M
(2016)
An improved limit on the charge of antihydrogen from stochastic acceleration.
in Nature
Ahmadi M
(2017)
Observation of the hyperfine spectrum of antihydrogen.
in Nature
Ahmadi M
(2017)
Observation of the 1S-2S transition in trapped antihydrogen.
in Nature
ALPHA Collaboration
(2009)
Antiproton, positron, and electron imaging with a microchannel plate/phosphor detector.
in The Review of scientific instruments
ALPHA Collaboration
(2013)
Description and first application of a new technique to measure the gravitational mass of antihydrogen.
in Nature communications
Amole C
(2012)
Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap
in New Journal of Physics
Amole C
(2012)
Alternative method for reconstruction of antihydrogen annihilation vertices
in Hyperfine Interactions
Amole C
(2012)
Resonant quantum transitions in trapped antihydrogen atoms.
in Nature
Amole C
(2014)
The ALPHA antihydrogen trapping apparatus
in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Andresen G
(2009)
Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning-Malmberg trap used for antihydrogen trapping
in Physics of Plasmas
Andresen G
(2008)
A novel antiproton radial diagnostic based on octupole induced ballistic loss
in Physics of Plasmas
Andresen G
(2011)
Search for trapped antihydrogen
in Physics Letters B
Andresen G
(2012)
The ALPHA - detector: Module Production and Assembly
in Journal of Instrumentation
Andresen G
(2007)
Antimatter plasmas in a multipole trap for antihydrogen.
in Physical review letters
Andresen G
(2012)
Antihydrogen annihilation reconstruction with the ALPHA silicon detector
in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Andresen G
(2010)
Antihydrogen formation dynamics in a multipolar neutral anti-atom trap
in Physics Letters B
Andresen GB
(2010)
Trapped antihydrogen.
in Nature
Andresen GB
(2010)
Evaporative cooling of antiprotons to cryogenic temperatures.
in Physical review letters
Andresen GB
(2011)
Autoresonant excitation of antiproton plasmas.
in Physical review letters
Andresen GB
(2011)
Centrifugal separation and equilibration dynamics in an electron-antiproton plasma.
in Physical review letters
Ashkezari M
(2011)
Progress towards microwave spectroscopy of trapped antihydrogen
in Hyperfine Interactions
Baker C
(2018)
Excitation of positronium: from the ground state to Rydberg levels
in Journal of Physics B: Atomic, Molecular and Optical Physics
Baker C
(2008)
Weakly bound positron-electron pairs in a strong magnetic field
in Journal of Physics B: Atomic, Molecular and Optical Physics
Bertsche W
(2015)
Physics with antihydrogen
in Journal of Physics B: Atomic, Molecular and Optical Physics
Bertsche W
(2017)
Cold neutral atoms via charge exchange from excited state positronium: a proposal
in New Journal of Physics
Bertsche W
(2011)
Antihydrogen formation by autoresonant excitation of antiproton plasmas
in Hyperfine Interactions
Butler E
(2011)
Trapped antihydrogen
in Hyperfine Interactions
Butler E
(2011)
Towards antihydrogen trapping and spectroscopy at ALPHA
in Hyperfine Interactions
Capra A
(2016)
Limit on the electric charge of antihydrogen
in Hyperfine Interactions
Charlton M
(2013)
Antihydrogen in a bottle
in Physics Education
Charlton M
(2015)
Advances in antihydrogen physics.
in Science progress
Charlton M
(2016)
Heating due to momentum transfer in low-energy positronium-antiproton scattering
in Physical Review A
Charlton M
(2017)
Closing in on the properties of antihydrogen
in The European Physical Journal D
Charlton M
(2017)
Special issue on antihydrogen and positronium
in Journal of Physics B: Atomic, Molecular and Optical Physics
Charlton M
(2008)
Antihydrogen for precision tests in physics
in Contemporary Physics
Charlton M
(2011)
Antiparticle sources for antihydrogen production and trapping
in Journal of Physics: Conference Series
Colucci M
(2011)
The temperature and density dependence of positron annihilation in CO 2 and SF 6
in Journal of Physics B: Atomic, Molecular and Optical Physics
Deller A
(2015)
Exciting positronium with a solid-state UV laser: the Doppler-broadened Lyman- a transition
in Journal of Physics B: Atomic, Molecular and Optical Physics
Friesen T
(2012)
Microwave-plasma interactions studied via mode diagnostics in ALPHA
in Hyperfine Interactions
Fujiwara M
(2007)
Towards antihydrogen confinement with the ALPHA antihydrogen trap
in Hyperfine Interactions
Fujiwara MC
(2008)
Temporally controlled modulation of antihydrogen production and the temperature scaling of antiproton-positron recombination.
in Physical review letters
Funakoshi R
(2007)
Positron plasma control techniques for the production of cold antihydrogen
in Physical Review A
Gutierrez A
(2015)
Antiproton cloud compression in the ALPHA apparatus at CERN
in Hyperfine Interactions
Hydomako R
(2011)
Antihydrogen detection in ALPHA
in Hyperfine Interactions
Indelicato P
(2014)
The Gbar project, or how does antimatter fall?
in Hyperfine Interactions
Isaac C
(2011)
Compression of Positron Clouds in the Independent Particle Regime
in Physical Review Letters
Jonsell S
(2010)
Simulations of antihydrogen formation in a nested Penning trap
in Journal of Physics: Conference Series
Jonsell S
(2016)
The role of antihydrogen formation in the radial transport of antiprotons in positron plasmas
in Journal of Physics B: Atomic, Molecular and Optical Physics
Jonsell S
(2009)
Simulation of the formation of antihydrogen in a nested Penning trap: effect of positron density
in Journal of Physics B: Atomic, Molecular and Optical Physics
Description | In the last year we have been able to observe the 1S-2S transition of antihydrogen and to observe the hyperfine spectrum of the anti-atom. |
Exploitation Route | The findings obtained during the grant were essential to make progress towards the final goal of testing CPT conservation by comparing the 1S-2S transition of antihydrogen with that of hydrogen. |
Sectors | Other |
Description | Our findings have been used by many scientists to justify theoretical and experimental work in number of areas of basic physics. Organisations such as CERN and our institutions have used our work to promote their respective missions, and in the public understanding of science. |
First Year Of Impact | 2011 |
Sector | Other |
Impact Types | Cultural |
Description | ALPHA Collaboration |
Organisation | European Organization for Nuclear Research (CERN) |
Department | ALPHA Experiment |
Country | Switzerland |
Sector | Public |
PI Contribution | As co-founders of the collaboration, we have provided funding and expertise in multiple areas of key importance to this experiment : Super conducting magnets, Lasers, Plasma physics, Trap physics, Antiproton physics, Antitrapping, Positrons, Positron accumulation, Cryogenics. |
Collaborator Contribution | Partners and expertise (in parenthesis) are come from Brazil (Lasers), Canada (Detectors/DAQ), Denmark (Lasers, Antihydrogen), UK (Detectors, Plasma physics plus the above), US (plasma physics, Simulation). The contributations are estimated based on 10 year running of the experiment with 30 academics contributing cash for running and maintenance and about 20 FTE's per year of running plus 3M of contributions of kit. |
Impact | This is an enormously successful collaboration having resulted in 4 Nature papers and a large volume of other papers as well as heavy representation in the media. It is physics-multidisciplinary in that the collaboration spans several normally separate areas of physics : cryogenics, plasma physics, atomic physics, particle physics, fundamental physics, laser physics, positron physics, and spectroscopy |
Start Year | 2006 |
Description | CERN |
Organisation | European Organization for Nuclear Research (CERN) |
Country | Switzerland |
Sector | Academic/University |
Start Year | 2006 |
Description | CERN Open Weekend: 2 talks about Antimatter |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | A large number of question after the talks I don't know |
Year(s) Of Engagement Activity | 2013 |
Description | Royal society summer exhibition |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Exhibition about physics at CERN |
Year(s) Of Engagement Activity | 2016 |
Description | Times Cheltenham Science Festival: Particle Physics: An Introduction" co-presented with Dr Tom Whyntie |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | A number of questions after the talk were answered None |
Year(s) Of Engagement Activity | 2013 |
URL | http://www.cheltenhamfestivals.com/science/whats-on/2013/particle-physics-an-introduction/ |