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Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Allen AH, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Neveling R, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, Van de Wiele J, van Oers WTH, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, Zeps V. Transverse beam spin asymmetries in forward-angle elastic electron-proton scattering. Phys Rev Lett 2007; 99:092301. [PMID: 17930999 DOI: 10.1103/physrevlett.99.092301] [Citation(s) in RCA: 2] [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: 05/11/2007] [Indexed: 05/25/2023]
Abstract
We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q2=0.15, 0.25 (GeV/c)2. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A(n) provides a direct probe of the imaginary component of the 2gamma exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.
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Affiliation(s)
- D S Armstrong
- Department of Physics, College of William and Mary, Williamsburg, Virginia 23187, USA
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Jamieson B, Bayes R, Davydov YI, Depommier P, Doornbos J, Faszer W, Fujiwara MC, Gagliardi CA, Gaponenko A, Gill DR, Gumplinger P, Hasinoff MD, Henderson RS, Hu J, Kitching P, Koetke DD, Macdonald JA, MacDonald RP, Marshall GM, Mathie EL, Mischke RE, Musser JR, Nozar M, Olchanski K, Olin A, Openshaw R, Porcelli TA, Poutissou JM, Poutissou R, Quraan MA, Rodning NL, Selivanov V, Sheffer G, Shin B, Stanislaus TDS, Tacik R, Torokhov VD, Tribble RE, Vasiliev MA. Measurement ofPμξin polarized muon decay. Int J Clin Exp Med 2006. [DOI: 10.1103/physrevd.74.072007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Armstrong DS, Arvieux J, Asaturyan R, Averett T, Bailey SL, Batigne G, Beck DH, Beise EJ, Benesch J, Bimbot L, Birchall J, Biselli A, Bosted P, Boukobza E, Breuer H, Carlini R, Carr R, Chant N, Chao YC, Chattopadhyay S, Clark R, Covrig S, Cowley A, Dale D, Davis C, Falk W, Finn JM, Forest T, Franklin G, Furget C, Gaskell D, Grames J, Griffioen KA, Grimm K, Guillon B, Guler H, Hannelius L, Hasty R, Hawthorne Allen A, Horn T, Johnston K, Jones M, Kammel P, Kazimi R, King PM, Kolarkar A, Korkmaz E, Korsch W, Kox S, Kuhn J, Lachniet J, Lee L, Lenoble J, Liatard E, Liu J, Loupias B, Lung A, MacLachlan GA, Marchand D, Martin JW, McFarlane KW, McKee DW, McKeown RD, Merchez F, Mkrtchyan H, Moffit B, Morlet M, Nakagawa I, Nakahara K, Nakos M, Neveling R, Niccolai S, Ong S, Page S, Papavassiliou V, Pate SF, Phillips SK, Pitt ML, Poelker M, Porcelli TA, Quéméner G, Quinn B, Ramsay WD, Rauf AW, Real JS, Roche J, Roos P, Rutledge GA, Secrest J, Simicevic N, Smith GR, Spayde DT, Stepanyan S, Stutzman M, Sulkosky V, Tadevosyan V, Tieulent R, van de Wiele J, van Oers W, Voutier E, Vulcan W, Warren G, Wells SP, Williamson SE, Wood SA, Yan C, Yun J, Zeps V. Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment. Phys Rev Lett 2005; 95:092001. [PMID: 16197209 DOI: 10.1103/physrevlett.95.092001] [Citation(s) in RCA: 12] [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: 06/17/2005] [Indexed: 05/04/2023]
Abstract
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.
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Affiliation(s)
- D S Armstrong
- Department of Physics, College of William and Mary, Williamsburg, VA 23187, USA
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Musser JR, Bayes R, Davydov YI, Depommier P, Doornbos J, Faszer W, Gagliardi CA, Gaponenko A, Gill DR, Green P, Gumplinger P, Hasinoff MD, Henderson RS, Hu J, Jamieson B, Kitching P, Koetke DD, Krushinsky AA, Lachin YY, Macdonald JA, MacDonald RP, Marshall GM, Mathie EL, Miasoedov LV, Mischke RE, Nord PM, Olchanski K, Olin A, Openshaw R, Porcelli TA, Poutissou JM, Poutissou R, Quraan MA, Rodning NL, Selivanov V, Sheffer G, Shin B, Sobratee F, Stanislaus TDS, Tacik R, Torokhov VD, Tribble RE, Vasiliev MA, Wright DH. Measurement of the Michel parameter rho in muon decay. Phys Rev Lett 2005; 94:101805. [PMID: 15783475 DOI: 10.1103/physrevlett.94.101805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Indexed: 05/24/2023]
Abstract
The TWIST Collaboration has measured the Michel parameter rho in normal muon decay, mu(+)--> e(+)nu(e)nu (mu). In the standard model, rho = 3/4. Deviations from this value imply mixing of left- and right-handed muon and electron couplings. We find rho=0.750 80+/-0.000 32(stat) +/- 0.000 97(syst) +/- 0.000 23, where the last uncertainty represents the dependence of rho on the Michel parameter eta. This result sets new limits on the W(L)-W(R) mixing angle in left-right symmetric models.
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Affiliation(s)
- J R Musser
- Texas A&M University, College Station, Texas 77843, USA
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Opper AK, Korkmaz E, Hutcheon DA, Abegg R, Davis CA, Finlay RW, Green PW, Greeniaus LG, Jordan DV, Niskanen JA, O'Rielly GV, Porcelli TA, Reitzner SD, Walden PL, Yen S. Charge symmetry breaking in np-->dpi(0). Phys Rev Lett 2003; 91:212302. [PMID: 14683292 DOI: 10.1103/physrevlett.91.212302] [Citation(s) in RCA: 2] [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: 06/05/2003] [Indexed: 05/24/2023]
Abstract
The forward-backward asymmetry in np-->dpi(0), which must be zero in the center-of-mass system if charge symmetry is respected, has been measured to be [17.2+/-8.0(stat)+/-5.5(syst)]x10(-4), at an incident neutron energy of 279.5 MeV. This observable is compared to recent chiral effective field theory calculations, with implications regarding the du quark mass difference.
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Affiliation(s)
- A K Opper
- Ohio University, Athens, Ohio 45701, USA.
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Porcelli TA, Adamczak A, Bailey JM, Beer GA, Douglas JL, Faifman MP, Fujiwara MC, Huber TM, Kammel P, Kim SK, Knowles PE, Kunselman AR, Maier M, Markushin VE, Marshall GM, Mason GR, Mulhauser F, Olin A, Petitjean C, Zmeskal J. Measurement of the resonant d(mu)t molecular formation rate in solid HD. Phys Rev Lett 2001; 86:3763-3766. [PMID: 11329318 DOI: 10.1103/physrevlett.86.3763] [Citation(s) in RCA: 3] [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: 12/20/2000] [Indexed: 05/23/2023]
Abstract
Measurements of muon-catalyzed dt fusion ( d(mu)t-->4He + n + mu(-)) in solid HD have been performed. The theory describing the energy dependent resonant molecular formation rate for the reaction (mu)t + HD-->[(d(mu)t)pee](*) is compared to experimental results in a pure solid HD target. Constraints on the rates are inferred through the use of a Monte Carlo model developed specifically for the experiment. From the time-of-flight analysis of fusion events in 16 and 37 microg x cm(-2) targets, an average formation rate consistent with 0.897+/-(0.046)(stat)+/-(0.166)(syst) times the theoretical prediction was obtained.
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Affiliation(s)
- T A Porcelli
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada V8W 3P6
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Fujiwara MC, Adamczak A, Bailey JM, Beer GA, Beveridge JL, Faifman MP, Huber TM, Kammel P, Kim SK, Knowles PE, Kunselman AR, Maier M, Markushin VE, Marshall GM, Martoff CJ, Mason GR, Mulhauser F, Olin A, Petitjean C, Porcelli TA, Wozniak J, Zmeskal J. Resonant formation of d&mgr;t molecules in deuterium: An atomic beam measurement of muon catalyzed dt fusion. Phys Rev Lett 2000; 85:1642-1645. [PMID: 10970578 DOI: 10.1103/physrevlett.85.1642] [Citation(s) in RCA: 2] [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: 02/29/2000] [Revised: 05/18/2000] [Indexed: 05/23/2023]
Abstract
Resonant formation of d&mgr;t molecules in collisions of muonic tritium ( &mgr;t) on D2 was investigated using a beam of &mgr;t atoms, demonstrating a new direct approach in muon catalyzed fusion studies. Strong epithermal resonances in d&mgr;t formation were directly revealed for the first time. From the time-of-flight analysis of 2036+/-116 dt fusion events, a formation rate consistent with 0.73+/-(0.16)(meas)+/-(0.09)(model) times the theoretical prediction was obtained. For the largest peak at a resonance energy of 0.423+/-0.037 eV, this corresponds to a rate of (7.1+/-1.8)x10(9) s(-1), more than an order of magnitude larger than those at low energies.
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Affiliation(s)
- MC Fujiwara
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 2A6 and TRIUMF, Vancouver, Canada V6T 2A3
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