start-ver=1.4 cd-journal=joma no-vol=798 cd-vols= no-issue= article-no= start-page=134980 end-page= dt-received= dt-revised= dt-accepted= dt-pub-year=2019 dt-pub=20191110 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Search for heavy neutrinos in pi > mu nu decay en-subtitle= kn-subtitle= en-abstract= kn-abstract=In the present work of the PIENU experiment, heavy neutrinos were sought in pion decays pi(+) -> mu(+)nu at rest by examining the observed muon energy spectrum for extra peaks in addition to the expected peak for a light neutrino. No evidence for heavy neutrinos was observed. Upper limits were set on the neutrino mixing matrix vertical bar U-mu i vertical bar(2) in the neutrino mass region of 15.7-33.8 MeV/c(2), improving on previous results by an order of magnitude. (C) 2019 The Authors. Published by Elsevier B.V. en-copyright= kn-copyright= en-aut-name=Aguilar-ArevaloA. en-aut-sei=Aguilar-Arevalo en-aut-mei=A. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=AokiM. en-aut-sei=Aoki en-aut-mei=M. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=BlecherM. en-aut-sei=Blecher en-aut-mei=M. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=BrittonD.I. en-aut-sei=Britton en-aut-mei=D.I. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=vom BruchBruch, D. en-aut-sei=vom Bruch en-aut-mei=Bruch, D. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=BrymanD. A. en-aut-sei=Bryman en-aut-mei=D. A. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= en-aut-name=ChenS. en-aut-sei=Chen en-aut-mei=S. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=7 ORCID= en-aut-name=ComfortJ. en-aut-sei=Comfort en-aut-mei=J. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=8 ORCID= en-aut-name=DoriaL. en-aut-sei=Doria en-aut-mei=L. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=9 ORCID= en-aut-name=Cuen-RochinS. en-aut-sei=Cuen-Rochin en-aut-mei=S. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=10 ORCID= en-aut-name=GumplingerP. en-aut-sei=Gumplinger en-aut-mei=P. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=11 ORCID= en-aut-name=HusseinA. en-aut-sei=Hussein en-aut-mei=A. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=12 ORCID= en-aut-name=IgarashiY. en-aut-sei=Igarashi en-aut-mei=Y. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=13 ORCID= en-aut-name=ItoS. en-aut-sei=Ito en-aut-mei=S. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=14 ORCID= en-aut-name=KettellS. H. en-aut-sei=Kettell en-aut-mei=S. H. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=15 ORCID= en-aut-name=KurchaninovL. en-aut-sei=Kurchaninov en-aut-mei=L. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=16 ORCID= en-aut-name=LittenbergL. S. en-aut-sei=Littenberg en-aut-mei=L. S. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=17 ORCID= en-aut-name=MalbrunotC. en-aut-sei=Malbrunot en-aut-mei=C. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=18 ORCID= en-aut-name=MischkeR. E. en-aut-sei=Mischke en-aut-mei=R. E. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=19 ORCID= en-aut-name=NumaoT. en-aut-sei=Numao en-aut-mei=T. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=20 ORCID= en-aut-name=ProtopopescuD. en-aut-sei=Protopopescu en-aut-mei=D. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=21 ORCID= en-aut-name=SherA. en-aut-sei=Sher en-aut-mei=A. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=22 ORCID= en-aut-name=SullivanT. en-aut-sei=Sullivan en-aut-mei=T. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=23 ORCID= en-aut-name=VavilovD. en-aut-sei=Vavilov en-aut-mei=D. kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=24 ORCID= affil-num=1 en-affil=Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de Mexico kn-affil= affil-num=2 en-affil=Graduate School of Science, Osaka University, kn-affil= affil-num=3 en-affil=Physics Department, Virginia Tech. kn-affil= affil-num=4 en-affil=School of Physics and Astronomy, University of Glasgow kn-affil= affil-num=5 en-affil=Department of Physics and Astronomy, University of British Columbia kn-affil= affil-num=6 en-affil=Department of Physics and Astronomy, University of British Columbia kn-affil= affil-num=7 en-affil=Department of Engineering Physics, Tsinghua University kn-affil= affil-num=8 en-affil=Physics Department, Arizona State University kn-affil= affil-num=9 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= affil-num=10 en-affil=Department of Physics and Astronomy, University of British Columbia kn-affil= affil-num=11 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= affil-num=12 en-affil=University of Northern British Columbia kn-affil= affil-num=13 en-affil=KEK kn-affil= affil-num=14 en-affil=Graduate School of Science, Osaka University kn-affil= affil-num=15 en-affil=Brookhaven National Laboratory kn-affil= affil-num=16 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= affil-num=17 en-affil=Brookhaven National Laboratory kn-affil= affil-num=18 en-affil=Department of Physics and Astronomy, University of British Columbia kn-affil= affil-num=19 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= affil-num=20 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= affil-num=21 en-affil=School of Physics and Astronomy, University of Glasgow kn-affil= affil-num=22 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= affil-num=23 en-affil=Department of Physics and Astronomy, University of British Columbia kn-affil= affil-num=24 en-affil=TRIUMF, 4004 Wesbrook Mall kn-affil= en-keyword=Pion decay kn-keyword=Pion decay en-keyword=Heavy neutrino kn-keyword=Heavy neutrino END