Measurement of the Formation Rate of Muonic Hydrogen Molecules
| Autor: | A. A. Vasilyev, K. R. Lynch, Jules Deutsch, An.A. Vorobyov, T. P. Gorringe, J. Egger, D. W. Hertzog, R. M. Carey, Malte Hildebrandt, O. Maev, P. Kammel, V.A. Ganzha, B. Kiburg, Stuart J. Freedman, Françoise Mulhauser, M. Vznuzdaev, P. Winter, René Prieels, T. I. Banks, V. A. Andreev, G. G. Semenchuk, Kenneth M. Crowe, T. Case, A. G. Krivshich, G. N. Schapkin, V. Tishchenko, M. A. Soroka, C. Petitjean, Bernhard Lauss, P. Kravtsov, E. M. Maev, S. Knaack, S. M. Clayton, G. E. Petrov, F. Gray |
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| Přispěvatelé: | UCL - SST/IRMP - Institut de recherche en mathématique et physique |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Physics
Nuclear and High Energy Physics Muon Physics - Instrumentation and Detectors Proton 010308 nuclear & particles physics FOS: Physical sciences Instrumentation and Detectors (physics.ins-det) Lambda Coupling (probability) 01 natural sciences High Energy Physics - Experiment Pseudoscalar High Energy Physics - Experiment (hep-ex) 0103 physical sciences Atom Molecule Nuclear Experiment (nucl-ex) Atomic physics 010306 general physics Nuclear Experiment Exotic atom |
| Zdroj: | Physical Review. C, Nuclear Physics, Vol. 91, no.5, p. 055502 [1-11] (2015) |
| Popis: | Background: The rate \lambda_pp\mu\ characterizes the formation of pp\mu\ molecules in collisions of muonic p\mu\ atoms with hydrogen. In measurements of the basic weak muon capture reaction on the proton to determine the pseudoscalar coupling g_P, capture occurs from both atomic and molecular states. Thus knowledge of \lambda_pp\mu\ is required for a correct interpretation of these experiments. Purpose: Recently the MuCap experiment has measured the capture rate \Lambda_S from the singlet p\mu\ atom, employing a low density active target to suppress pp\mu\ formation (PRL 110, 12504 (2013)). Nevertheless, given the unprecedented precision of this experiment, the existing experimental knowledge in \lambda_pp\mu\ had to be improved. Method: The MuCap experiment derived the weak capture rate from the muon disappearance rate in ultra-pure hydrogen. By doping the hydrogen with 20 ppm of argon, a competing process to pp\mu\ formation was introduced, which allowed the extraction of \lambda_pp\mu\ from the observed time distribution of decay electrons. Results: The pp\mu\ formation rate was measured as \lambda_pp\mu = (2.01 +- 0.06(stat) +- 0.03(sys)) 10^6 s^-1. This result updates the \lambda_pp\mu\ value used in the above mentioned MuCap publication. Conclusions: The 2.5x higher precision compared to earlier experiments and the fact that the measurement was performed at nearly identical conditions to the main data taking, reduces the uncertainty induced by \lambda_pp\mu\ to a minor contribution to the overall uncertainty of \Lambda_S and g_P, as determined in MuCap. Our final value for \lambda_pp\mu\ shifts \Lambda_S and g_P by less than one tenth of their respective uncertainties compared to our results published earlier. Comment: 12 pages, 6 figures, to be submitted to Phys. Rev. C |
| Databáze: | OpenAIRE |
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