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Webber DM, Tishchenko V, Peng Q, Battu S, Carey RM, Chitwood DB, Crnkovic J, Debevec PT, Dhamija S, Earle W, Gafarov A, Giovanetti K, Gorringe TP, Gray FE, Hartwig Z, Hertzog DW, Johnson B, Kammel P, Kiburg B, Kizilgul S, Kunkle J, Lauss B, Logashenko I, Lynch KR, McNabb R, Miller JP, Mulhauser F, Onderwater CJG, Phillips J, Rath S, Roberts BL, Winter P, Wolfe B. Measurement of the positive muon lifetime and determination of the Fermi constant to part-per-million precision. Phys Rev Lett 2011; 106:041803. [PMID: 21405320 DOI: 10.1103/physrevlett.106.041803] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Indexed: 05/30/2023]
Abstract
We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2×10(12) decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ(μ(+)) (MuLan)=2 196 980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G(F) (MuLan)=1.166 378 8(7)×10(-5) GeV(-2) (0.6 ppm). It is also used to extract the μ(-)p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g(P).
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Affiliation(s)
- D M Webber
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Jia Y, Gorringe TP, Hasinoff MD, Kovash MA, Ojha M, Pavan MM, Tripathi S, Zołnierczuk PA. Test of isospin symmetry via low-energy 1H(pi{-},pi{0})n charge exchange. Phys Rev Lett 2008; 101:102301. [PMID: 18851210 DOI: 10.1103/physrevlett.101.102301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Indexed: 05/26/2023]
Abstract
We report measurements of the pi;{-}p-->pi;{0}n differential cross sections at six momenta (104-143 MeV/c) and four angles (0 degrees -40 degrees ) by detection of gamma-ray pairs from pi;{0}-->gammagamma decays using a photon-pair spectrometer at TRIUMF. This kinematic region exhibits a vanishing zero-degree cross section from destructive interference between s and p waves, thus yielding special sensitivity to pion-nucleon dynamics. Our data and previous data do not agree, with important implications for earlier claims of large isospin-violating effects.
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Affiliation(s)
- Y Jia
- University of Kentucky, Lexington, Kentucky 40506, USA
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Chitwood DB, Banks TI, Barnes MJ, Battu S, Carey RM, Cheekatmalla S, Clayton SM, Crnkovic J, Crowe KM, Debevec PT, Dhamija S, Earle W, Gafarov A, Giovanetti K, Gorringe TP, Gray FE, Hance M, Hertzog DW, Hare MF, Kammel P, Kiburg B, Kunkle J, Lauss B, Logashenko I, Lynch KR, McNabb R, Miller JP, Mulhauser F, Onderwater CJG, Ozben CS, Peng Q, Polly CC, Rath S, Roberts BL, Tishchenko V, Wait GD, Wasserman J, Webber DM, Winter P, Zołnierczuk PA. Improved measurement of the positive-muon lifetime and determination of the Fermi constant. Phys Rev Lett 2007; 99:032001. [PMID: 17678280 DOI: 10.1103/physrevlett.99.032001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Indexed: 05/16/2023]
Abstract
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau(micro)=2.197 013(24) micros, is in excellent agreement with the previous world average. The new world average tau(micro)=2.197 019(21) micros determines the Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).
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Affiliation(s)
- D B Chitwood
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Clark JHD, Armstrong DS, Gorringe TP, Hasinoff MD, King PM, Stocki TJ, Tripathi S, Wright DH, Zolnierczuk PA. Ortho-para transition rate in mu-molecular hydrogen and the proton's induced pseudoscalar coupling gp. Phys Rev Lett 2006; 96:073401. [PMID: 16606087 DOI: 10.1103/physrevlett.96.073401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Indexed: 05/08/2023]
Abstract
We report a measurement of the ortho-para transition rate in the p mu p molecule. The experiment was conducted at TRIUMF via the measurement of the time dependence of the 5.2 MeV neutrons from muon capture in liquid hydrogen. The measurement yielded an ortho-para rate Lambda op = (11.1 +/- 1.7 +/-(0.9)(0.6)) x 10(4) s(-1), which is substantially larger than the earlier result of Bardin et al. The result has striking implications for the proton's induced pseudoscalar coupling g(p), changing the value of g(p) obtained from the most precise ordinary muon capture measurement from 10.6 +/- 2.7 to 0.8 +/- 2.8, and from the sole radiative muon capture measurement from 12.2 +/- 1.1 to 10.6 +/- 1.2, bringing the latter result closer to theoretical predictions.
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Affiliation(s)
- J H D Clark
- College of William and Mary, Williamsburg, Virginia 23187, USA
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Tripathi S, Armstrong DS, Christy ME, Clark JHD, Gorringe TP, Hasinoff MD, Kovash MA, Wright DH, Zołnierczuk PA. Observation of double radiative capture on pionic hydrogen. Phys Rev Lett 2002; 89:252501. [PMID: 12484878 DOI: 10.1103/physrevlett.89.252501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2002] [Revised: 09/03/2002] [Indexed: 05/24/2023]
Abstract
We report the first observation of double radiative capture on pionic hydrogen. The experiment was conducted at the TRIUMF cyclotron using the RMC spectrometer and detected gamma-ray coincidences following pi(-) stops in liquid hydrogen. We found the branching ratio for double radiative capture to be [3.05+/-0.27(stat)+/-0.31(syst)]x10(-5). The measured branching ratio and angle-energy distributions support the theoretical prediction of a dominant contribution from the pipi-->gammagamma annihilation mechanism.
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Affiliation(s)
- S Tripathi
- University of Kentucky, Lexington 40506, USA
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Jonkmans G, Ahmad S, Armstrong DS, Azuelos G, Bertl W, Blecher M, Chen CQ, Depommier P, Doyle BC, Gorringe TP, Gumplinger P, Hasinoff MD, Healey D, Larabee AJ, Macdonald JA, McDonald SC, Munro M, Poutissou J, Poutissou R, Robertson BC, Sample DG, Saettler E, Sigler CM, Taylor GN, Wright DH, Zhang NS. Radiative Muon Capture on Hydrogen and the Induced Pseudoscalar Coupling. Phys Rev Lett 1996; 77:4512-4515. [PMID: 10062557 DOI: 10.1103/physrevlett.77.4512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Johnson BL, Gorringe TP, Armstrong DS, Bauer J, Hasinoff MD, Kovash MA, Measday DF, Moftah BA, Porter R, Wright DH. Observables in muon capture on 23Na and the effective weak couplings g-tildea and g-tildep. Phys Rev C Nucl Phys 1996; 54:2714-2731. [PMID: 9971625 DOI: 10.1103/physrevc.54.2714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Siebels B, Gorringe TP, Alford WP, Bauer J, Evans J, El-Kateb S, Jackson KP, Trudel A, Yen S. Gamow-Teller strength in 23Na(n,p) and a comparison to 23Na( micro-, nu ). Phys Rev C Nucl Phys 1995; 52:1488-1497. [PMID: 9970652 DOI: 10.1103/physrevc.52.1488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Gorringe TP, Johnson BL, Armstrong DS, Bauer J, Kovash MA, Hasinoff MD, Measday DF, Moftah BA, Porter R, Wright DH. Hyperfine effect in micro- capture on 23Na and gp/ga. Phys Rev Lett 1994; 72:3472-3475. [PMID: 10056208 DOI: 10.1103/physrevlett.72.3472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Armstrong DS, Serna-Angel A, Ahmad S, Azuelos G, Bertl W, Blecher M, Chen CQ, Depommier P, Gorringe TP, Hasinoff MD, Henderson RS, Larabee AJ, Macdonald JA, McDonald SC, Poutissou JM, Poutissou R, Robertson BC, Sample DG, Taylor GN, Wright DH, Zhang NS. Radiative muon capture on Al, Si, Ca, Mo, Sn, and Pb. Phys Rev C Nucl Phys 1992; 46:1094-1107. [PMID: 9968215 DOI: 10.1103/physrevc.46.1094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Armstrong DS, Ahmad S, Burnham RA, Gorringe TP, Hasinoff MD, Larabee AJ, Waltham CE, Azuelos G, Macdonald JA, Numao T, Poutissou JM, Blecher M, Wright DH, Clifford ET, Summhammer J, Depommier P, Poutissou R, Mes H, Robertson BC. Radiative muon capture on carbon, oxygen, and calcium. Phys Rev C Nucl Phys 1991; 43:1425-1447. [PMID: 9967183 DOI: 10.1103/physrevc.43.1425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Gorringe TP, Ahmad S, Armstrong DS, Burnham RA, Hasinoff MD, Larabee AJ, Waltham CE, Azuelos G, Macdonald JA, Poutissou JM, Blecher M, Wright DH, Depommier P, Poutissou R, Clifford ET. Search for the tetraneutron using the reaction 4He( pi -, pi +)4n. Phys Rev C Nucl Phys 1989; 40:2390-2393. [PMID: 9966238 DOI: 10.1103/physrevc.40.2390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Armstrong DS, Ahmad S, Burnham RA, Gorringe TP, Hasinoff MD, Larabee AJ, Waltham CE, Azuelos G, Macdonald JA, Poutissou JM, Blecher M, Wright DH, Clifford ET, Summhammer J, Depommier P, Poutissou R, Mes H, Robertson BC. Radiative muon capture on oxygen and the induced pseudoscalar coupling. Phys Rev C Nucl Phys 1989; 40:1100-1103. [PMID: 9966079 DOI: 10.1103/physrevc.40.r1100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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