[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-seo-155112-105":3,"detail-sidebar-cat-0-en-105":81,"doc-detail-155112-en":131},{"code":4,"msg":5,"data":6},0,"ok",{"site_id":7,"language":8,"slug":9,"title":10,"keywords":11,"description":12,"schema_data":13,"social_meta":74,"head_meta":76,"extra_data":78,"updated_unix":80},105,"en","mulan-measurement-determination-of-the-fermi-constant","MuLan measurement - Determination of the Fermi constant","","Detailed report of the MuLan precision measurement of the positive muon lifetime and its use to determine the Fermi constant. The experiment ran at the Paul Scherrer Institute with a time-structured, nearly 100% polarized surface muon beam and a segmented fast-timing plastic scintillator array. Two magnetic target setups were used: a magnetized ferromagnetic target with a 4 kG internal field and a quartz target with a 130 G external field. The results yield a muon lifetime and the corresponding GF value, enabling improved weak-interaction studies through muonic atom lifetime measurements.",{"@graph":14,"@context":73},[15,34,56],{"@type":16,"itemListElement":17},"BreadcrumbList",[18,23,27,31],{"item":19,"name":20,"@type":21,"position":22},"https://docshare.wps.com","Home","ListItem",1,{"item":24,"name":25,"@type":21,"position":26},"https://docshare.wps.com/document/","Document",2,{"item":28,"name":29,"@type":21,"position":30},"https://docshare.wps.com/document/research-report/","Research & Report",3,{"item":32,"name":10,"@type":21,"position":33},"https://docshare.wps.com/document/mulan-measurement-determination-of-the-fermi-constant/155112/",4,{"url":32,"name":10,"@type":35,"image":36,"author":41,"headline":10,"publisher":44,"fileFormat":47,"inLanguage":8,"description":12,"dateModified":48,"datePublished":49,"encodingFormat":47,"isAccessibleForFree":50,"interactionStatistic":51},"DigitalDocument",{"url":37,"@type":38,"width":39,"height":40},"https://docshare.wps.com/thumbnails/mulan-measurement-determination-of-the-fermi-constant/155112.png","ImageObject",300,407,{"name":42,"@type":43},"Gloria","Person",{"url":19,"name":45,"@type":46},"DocShare","Organization","application/pdf","2026-10-19","2026-08-28",true,{"@type":52,"interactionType":53,"userInteractionCount":55},"InteractionCounter",{"@type":54},"ViewAction",14,{"@type":57,"mainEntity":58},"FAQPage",[59,65,69],{"name":60,"@type":61,"acceptedAnswer":62},"What was measured in the MuLan experiment?","Question",{"text":63,"@type":64},"The experiment performed a precision measurement of the positive muon lifetime using time-structured, highly polarized muon beams and fast segmented scintillator timing.","Answer",{"name":66,"@type":61,"acceptedAnswer":67},"How does the muon lifetime connect to the Fermi constant?",{"text":68,"@type":64},"The muon lifetime provides a precise input to the Fermi constant through a theoretical relation where electromagnetic radiative corrections are calculated to high order.",{"name":70,"@type":61,"acceptedAnswer":71},"What magnetic target arrangements were used?",{"text":72,"@type":64},"Two setups were used: a magnetized ferromagnetic target with an internal 4 kG field and a crystal quartz target exposed to an external 130 G magnetic field.","https://schema.org",{"og:url":32,"og:type":75,"og:title":10,"og:site_name":45,"og:description":12},"article",{"robots":77,"canonical":32},"index,follow",{"doc_id":79,"site_id":7},155112,1787905357,{"code":4,"msg":82,"data":83},"success",[84,88,92,96,101,106,111,115,120,123,127],{"id":22,"doc_module":4,"doc_module_name":25,"category_name":85,"show_sort_weight":86,"slug":87},"Story & Novel",90,"story-novel",{"id":26,"doc_module":4,"doc_module_name":25,"category_name":89,"show_sort_weight":90,"slug":91},"Literature",80,"literature",{"id":33,"doc_module":4,"doc_module_name":25,"category_name":93,"show_sort_weight":94,"slug":95},"Exam",70,"exam",{"id":97,"doc_module":4,"doc_module_name":25,"category_name":98,"show_sort_weight":99,"slug":100},5,"Comic",60,"comic",{"id":102,"doc_module":4,"doc_module_name":25,"category_name":103,"show_sort_weight":104,"slug":105},6,"Technology",50,"technology",{"id":107,"doc_module":4,"doc_module_name":25,"category_name":108,"show_sort_weight":109,"slug":110},7,"Healthcare",40,"healthcare",{"id":112,"doc_module":4,"doc_module_name":25,"category_name":29,"show_sort_weight":113,"slug":114},8,30,"research-report",{"id":116,"doc_module":4,"doc_module_name":25,"category_name":117,"show_sort_weight":118,"slug":119},9,"Religion & Spirituality",20,"religion-spirituality",{"id":118,"doc_module":4,"doc_module_name":25,"category_name":121,"show_sort_weight":118,"slug":122},"World Cup","world-cup",{"id":124,"doc_module":4,"doc_module_name":25,"category_name":125,"show_sort_weight":124,"slug":126},10,"Lifestyle","lifestyle",{"id":128,"doc_module":4,"doc_module_name":25,"category_name":129,"show_sort_weight":97,"slug":130},19,"General","general",{"code":4,"msg":82,"data":132},{"doc_id":79,"user_id":133,"nickname":42,"user_avatar":134,"doc_module":4,"category_id":112,"category_name":29,"doc_title":10,"doc_description":12,"doc_content":135,"file_id":136,"file_url":137,"file_type":138,"file_size":139,"view_count":55,"is_deleted":4,"is_public":22,"is_downloadable":22,"audit_status":22,"page_count":113,"language":140,"language_code":8,"site_id":7,"html_lang":8,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":12,"update_tm":80,"read_time":144,"preview_page_count":4},2336474459895,"https://ap-avatar.wpscdn.com/avatar/22000baeef7a5ed0655?x-image-process=image/resize,m_fixed,w_180,h_180&k=1786071322749376916","PHYSICAL REVIEW D 87, 052003 (2013)  \nDetailed report of the MuLan measurement of the positive muon lifetime and  \ndetermination of the Fermi constant  \nV. Tishchenko, 1 S. Battu, 1 R. M. Carey,2 D. B. Chitwood,3 J. Crnkovic,3 P. T. Debevec,3 S. Dhamija, 1 W. Earle,2  \nA. Gafarov,2 K. Giovanetti,4 T. P. Gorringe, 1 F. E. Gray,5 Z. Hartwig,2 D. W. Hertzog,3,6 B. Johnson,7 P. Kammel,3,6  \nB. Kiburg,3 S. Kizilgul,3 J. Kunkle,3 B. Lauss,8 I. Logashenko,2 K. R. Lynch,2,9 R. McNabb,3 J. P. Miller,2 F. Mulhauser,3,8  \nC. J. G. Onderwater,3,10 Q. Peng,2 J. Phillips,2 S. Rath, 1 B. L. Roberts,2 D. M. Webber,3 P. Winter,3 and B. Wolfe3  \n(MuLan Collaboration)  \n1Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA 2Department of Physics, Boston University, Boston, Massachusetts 02215, USA  \n3Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA  \n4Department of Physics, James Madison University, Harrisonburg, Virginia 22807, USA 5Department of Physics and Computational Science, Regis University, Denver, Colorado 80221, USA 6Department of Physics, University of Washington, Seattle, Washington 98195, USA 7Department of Mathematics and Physics, Kentucky Wesleyan College, Owensboro, Kentucky 42301, USA  \n8Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland  \n9Department of Earth and Physical Sciences, York College, City University of New York, Jamaica, New York 11451, USA  \n10Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen, The Netherlands  \n(Received 5 November 2012; published 4 March 2013)  \nWe present a detailed report of the method, setup, analysis, and results of a precision measurement of the positive muon lifetime. The experiment was conducted at the Paul Scherrer Institute using a timestructured, nearly 100% polarized surface muon beam and a segmented, fast-timing plastic scintillator array. The measurement employed two target arrangements: a magnetized ferromagnetic target with a  \n􀀁4 kG internal magnetic field and a crystal quartz target in a 130 G external magnetic field.  \nApproximately 1:6 􀀂 1012 positrons were accumulated and together the data yield a muon lifetime of  \n􀀁􀀂 ðMuLanÞ ¼ 2196980:3ð2:2Þ ps (1.0 ppm), 30 times more precise than previous generations of lifetime experiments. The lifetime measurement yields the most accurate value of the Fermi constant GF ðMuLanÞ ¼ 1:1663787ð6Þ􀀂 10 􀀃5 GeV 􀀃2 (0.5 ppm) . It also enables new precision studies of weak  \ninteractions via lifetime measurements of muonic atoms.  \nDOI: 10.1103/PhysRevD.87.052003 PACS numbers: 06.20.Jr, 12.15.Ji, 13.35.Bv, 14.60.Ef  \nI. INTRODUCTION  \nWeak interactions are germane to topics from big bang nucleosynthesis and stellar hydrogen burning, to archaeological dating and medical imaging, as well as fundamental nuclear and particle physics. Unlike electromagnetic and strong interactions, all known particles participate in weak interactions, and every process appears consistent with a universal strength for the weak force. This strength is governed by the Fermi constant [1] .  \nThe value of the Fermi constant GF is best determined by the measurement of the muon lifetime 􀀁􀀂 for two reasons: the muon lifetime is well suited to precision time measurements and the pure-leptonic character of muon decay permits an unambiguous theoretical interpretation. Until recently, the uncertainty in GF was 17 ppm; it originated from a 9 ppm contribution from the existing measurements of the muon lifetime and a 15 ppm contribution from the knowledge of the theoretical relation between the muon lifetime and the Fermi constant.  \nThe theoretical uncertainty arose from a limited knowledge of the two-loop QED corrections to the muon decay rate. In 1999, van Ritbergen and Stuart (vRS) evaluated these corrections, thus establishing the relation between GF and 􀀁􀀂 to the sub-ppm level [2–4] . Their work was the motivation for our part-per-million measurement of the pos","cbCaiecoSjMFqgvf","https://ap.wps.com/l/cbCaiecoSjMFqgvf","pdf",1477489,"English","# Introduction\n## Relation between GF and the muon lifetime","[{\"question\":\"What was measured in the MuLan experiment?\",\"answer\":\"The experiment performed a precision measurement of the positive muon lifetime using time-structured, highly polarized muon beams and fast segmented scintillator timing.\"},{\"question\":\"How does the muon lifetime connect to the Fermi constant?\",\"answer\":\"The muon lifetime provides a precise input to the Fermi constant through a theoretical relation where electromagnetic radiative corrections are calculated to high order.\"},{\"question\":\"What magnetic target arrangements were used?\",\"answer\":\"Two setups were used: a magnetized ferromagnetic target with an internal 4 kG field and a crystal quartz target exposed to an external 130 G magnetic field.\"}]","MuLan measurement - Determination of the Fermi constant | PDF",76]