| Title |
An improved limit on the charge of antihydrogen from stochastic acceleration
|
|---|---|
| Published in |
Nature, January 2016
|
| DOI | 10.1038/nature16491 |
| Pubmed ID | |
| Authors |
M. Ahmadi, M. Baquero-Ruiz, W. Bertsche, E. Butler, A. Capra, C. Carruth, C. L. Cesar, M. Charlton, A. E. Charman, S. Eriksson, L. T. Evans, N. Evetts, J. Fajans, T. Friesen, M. C. Fujiwara, D. R. Gill, A. Gutierrez, J. S. Hangst, W. N. Hardy, M. E. Hayden, C. A. Isaac, A. Ishida, S. A. Jones, S. Jonsell, L. Kurchaninov, N. Madsen, D. Maxwell, J. T. K. McKenna, S. Menary, J. M. Michan, T. Momose, J. J. Munich, P. Nolan, K. Olchanski, A. Olin, A. Povilus, P. Pusa, C. Ø. Rasmussen, F. Robicheaux, R. L. Sacramento, M. Sameed, E. Sarid, D. M. Silveira, C. So, T. D. Tharp, R. I. Thompson, D. P. van der Werf, J. S. Wurtele, A. I. Zhmoginov |
| Abstract |
Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q| < 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 less than that determined from the best previous measurement of the antihydrogen charge. The electrical charge of atoms and molecules of normal matter is known to be no greater than about 10(-21)e for a diverse range of species including H2, He and SF6. Charge-parity-time symmetry and quantum anomaly cancellation demand that the charge of antihydrogen be similarly small. Thus, our measurement constitutes an improved limit and a test of fundamental aspects of the Standard Model. If we assume charge superposition and use the best measured value of the antiproton charge, then we can place a new limit on the positron charge anomaly (the relative difference between the positron and elementary charge) of about one part per billion (one standard deviation), a 25-fold reduction compared to the current best measurement. |
X Demographics
The data shown below were collected from the profiles of 40 X users who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 5 | 13% |
| United Kingdom | 5 | 13% |
| Spain | 3 | 8% |
| Switzerland | 2 | 5% |
| Hong Kong | 1 | 3% |
| India | 1 | 3% |
| China | 1 | 3% |
| Georgia | 1 | 3% |
| France | 1 | 3% |
| Other | 3 | 8% |
| Unknown | 17 | 43% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Members of the public | 31 | 78% |
| Scientists | 6 | 15% |
| Science communicators (journalists, bloggers, editors) | 3 | 8% |
Mendeley readers
The data shown below were compiled from readership statistics for 43 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 1 | 2% |
| Unknown | 42 | 98% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 9 | 21% |
| Student > Ph. D. Student | 7 | 16% |
| Student > Master | 6 | 14% |
| Professor | 5 | 12% |
| Other | 4 | 9% |
| Other | 7 | 16% |
| Unknown | 5 | 12% |
| Readers by discipline | Count | As % |
|---|---|---|
| Physics and Astronomy | 31 | 72% |
| Chemistry | 3 | 7% |
| Psychology | 1 | 2% |
| Neuroscience | 1 | 2% |
| Arts and Humanities | 1 | 2% |
| Other | 0 | 0% |
| Unknown | 6 | 14% |
Attention Score in Context
This research output has an Altmetric Attention Score of 241. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 21 October 2022.
All research outputs
#156,027
of 25,402,889 outputs
Outputs from Nature
#9,832
of 97,886 outputs
Outputs of similar age
#2,624
of 403,481 outputs
Outputs of similar age from Nature
#222
of 912 outputs
Altmetric has tracked 25,402,889 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 99th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 97,886 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 102.4. This one has done well, scoring higher than 89% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 403,481 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 99% of its contemporaries.
We're also able to compare this research output to 912 others from the same source and published within six weeks on either side of this one. This one has done well, scoring higher than 75% of its contemporaries.