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{"id":24,"date":"2023-01-31T20:21:13","date_gmt":"2023-01-31T20:21:13","guid":{"rendered":"http:\/\/faculty.washington.edu\/hertzog\/wordpress\/?page_id=24"},"modified":"2025-01-01T22:03:27","modified_gmt":"2025-01-01T22:03:27","slug":"24-2","status":"publish","type":"page","link":"http:\/\/faculty.washington.edu\/hertzog\/","title":{"rendered":"Home"},"content":{"rendered":"\n

DAVID W. HERTZOG<\/strong><\/p>\n\n\n\n

Arthur B. McDonald Distinguished Professor of Physics<\/strong><\/p>\n\n\n\n

Director, Center for Experimental Nuclear Physics and Astrophysics<\/strong><\/p>\n\n\n\n

Department of Physics University of Washington<\/p>\n\n\n\n

Box 351560, Seattle WA 98195<\/p>\n\n\n\n

(206) 543-0839
hertzog@uw.edu<\/em><\/p>\n\n\n\n

\"\" — Most of our group at the Elba, 2019 Muon g-2 Collaboration Meeting<\/figcaption><\/figure>\n\n\n\n

<\/p>\n\n\n\n
Muon g-<\/em>2<\/strong>: Our group is engaged in a sub-ppm measurement of the muon’s anomalous magnetic moment (g-2).<\/em> The results of this experiment, when compared with precise theoretical calculations, are capable of revealing physics beyond the Standard Model attributed to SUSY particles of high mass, to structured intermediate vector bosons, or to substructure of the muon itself.\u00a0 Our final measurement, from the Brookhaven E821 Experiment, was more than 3 standard deviations from the current (2022) Standard Model expectation and the result has caused a significant buzz in the theoretical community. Our new experiment at Fermilab has been taking data through 6 years, acquiring more than 20 times the data obtained at BNL. Our first results — based on about 6% of the expected total — confirmed the BNL value and, when averaged together, increased the tension with the SM to more than 4 standard deviations. Our Run 2\/3 results further confirmed the measurement with increased precision. However, the comparison with the SM Theory is now a bit fuzzy given latest Lattice calculations and a new HVP measurement from CMD3. Until this is resolved, we can’t fully interpret the results. Meanwhile, we are pushing hard complete the Run 4\/5\/6 data analysies, representing 75% of our overall data set. Stay tuned for that soon in 2025.\u00a0 <\/p>\n\n\n\n
PIONEER  <\/strong>is a next-generation, rare-pion decay experiment that will take place at the Paul Scherrer Institute (PSI) in Switzerland. There are three main physics thrusts. The first priority will be the world\u2019s most sensitivity test of lepton flavor universality (LFU). It is strongly motivated by several inconsistencies between Standard Model (SM) predictions and data pointing towards the potential violation of LFU. The program will probe non-SM explanations of these anomalies through sensitivity to quantum effects of new particles, even if their masses are at very high scales. Measurement of the charged-pion branching ratio of electrons vs. muons is extremely sensitive to a wide variety of new physics effects. At present, the SM prediction is known to 1 part in 10^{4<\/sup>, which is 15 times more precise than the current experimental result<\/em>. An experiment reaching the theoretical accuracy will probe mass scales up to the PeV range.   A later stage of PIONEER will measure the ultra-rare pion beta branch, which is the cleanest way to obtain Vud and thus test CKM unitarity. Throughout PIONEER data taking, we will also improve the experimental limits by an order of magnitude or more on a host of exotic decays probing for effects of heavy neutrinos and dark sector physics. Pioneer is approved at PSI and we have been engaging in beam tests, in local development of LYSO calorimetry, and in developing the overall simulation framework.<\/p>\n\n\n\n}

Recently completed:<\/strong>
<\/p>\n\n\n\n
MuLan<\/strong>: The Muon Lifetime Analysis (MuLan) experiment measures the positive muon lifetime, which provides the most precise determination of the Fermi coupling constant, one of the fundamental inputs to the standard model. Recent advances in theory have reduced the theoretical uncertainty on the Fermi coupling constant as calculated from the muon lifetime to a few tenths of a ppm. The remaining uncertainty on the Fermi constant is entirely experimental and is dominated by the uncertainty on the muon lifetime. The MuLan experiment employs an innovative pulsed beam, a symmetric detector, and modern data-taking methods to reduce the uncertainty on the muon lifetime to 1 ppm. This experiment took place at the Paul Scherrer Institute, Switzerland.   We completed data taking, analysis, and several well-deserved Ph.D. theses. We proudly achieved our exact proposal goal of 1.0 ppm final precision, measured twice in blind experiments. The Fermi constant, so obtained, has a precision of 0.5 ppm. **Our final paper is here<\/a>. The photo at the right shows some of us having prepared the soccer-ball-shaped detector for shipping to PSI.<\/p>\n\n\n\n**
MuCap<\/strong>: The goal of the MuCap experiment is a 1% precision measurement of the muon capture rate on the proton. From the capture rate, the pseudoscalar form factor, g<\/em>_{P<\/sub>, of the nucleon will be extracted with 7% precision. This basic quantity is predicted theoretically with high precision, but the experimental situation was quite controversial. The first round of our experiment led an unambiguous value for g<\/em>_{P<\/sub> and a strong confirmation of the chiral symmetry of QCD at low energies. The success was based on the novel idea of capturing negative muons in ultra-pure hydrogen gas (not liquid) and, equally importantly, instrumenting the stopping volume in the manner of a time projection chamber (TPC). My colleague Peter Kammel invented the idea and led the effort from its inception. Two MuCap Ph.D. students were the co-winners of the APS Nuclear Physics Dissertation prize for the earliest phase of the work, and two others have since graduated on refinements. The}}final paper<\/a> demonstrated that the theory is right, a very notable achievement.
<\/p>\n\n\n\n
<\/div>\n","protected":false},"excerpt":{"rendered":"
DAVID W. HERTZOG Arthur B. McDonald Distinguished Professor of Physics Director, Center for Experimental Nuclear Physics and Astrophysics Department of Physics   University of Washington Box 351560, Seattle WA 98195 (206) 543-0839hertzog@uw.edu Appointments: College of William and Mary Ph.D., Physics 1983 Carnegie-Mellon University   Research Associate 1983-86 University of Illinois Assistant Professor, Physics 1986-92 University of Illinois Associate, …<\/p>\n
Home<\/span> Read More »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-global-header-display":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"class_list":["post-24","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/comments?post=24"}],"version-history":[{"count":13,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24\/revisions"}],"predecessor-version":[{"id":51,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24\/revisions\/51"}],"wp:attachment":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/media?parent=24"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

\"\" — Most of our group at the Elba, 2019 Muon g-2 Collaboration Meeting<\/figcaption><\/figure>\n\n\n\n

<\/p>\n\n\n\n
Muon g-<\/em>2<\/strong>: Our group is engaged in a sub-ppm measurement of the muon’s anomalous magnetic moment (g-2).<\/em> The results of this experiment, when compared with precise theoretical calculations, are capable of revealing physics beyond the Standard Model attributed to SUSY particles of high mass, to structured intermediate vector bosons, or to substructure of the muon itself.\u00a0 Our final measurement, from the Brookhaven E821 Experiment, was more than 3 standard deviations from the current (2022) Standard Model expectation and the result has caused a significant buzz in the theoretical community. Our new experiment at Fermilab has been taking data through 6 years, acquiring more than 20 times the data obtained at BNL. Our first results — based on about 6% of the expected total — confirmed the BNL value and, when averaged together, increased the tension with the SM to more than 4 standard deviations. Our Run 2\/3 results further confirmed the measurement with increased precision. However, the comparison with the SM Theory is now a bit fuzzy given latest Lattice calculations and a new HVP measurement from CMD3. Until this is resolved, we can’t fully interpret the results. Meanwhile, we are pushing hard complete the Run 4\/5\/6 data analysies, representing 75% of our overall data set. Stay tuned for that soon in 2025.\u00a0 <\/p>\n\n\n\n
PIONEER  <\/strong>is a next-generation, rare-pion decay experiment that will take place at the Paul Scherrer Institute (PSI) in Switzerland. There are three main physics thrusts. The first priority will be the world\u2019s most sensitivity test of lepton flavor universality (LFU). It is strongly motivated by several inconsistencies between Standard Model (SM) predictions and data pointing towards the potential violation of LFU. The program will probe non-SM explanations of these anomalies through sensitivity to quantum effects of new particles, even if their masses are at very high scales. Measurement of the charged-pion branching ratio of electrons vs. muons is extremely sensitive to a wide variety of new physics effects. At present, the SM prediction is known to 1 part in 10^{4<\/sup>, which is 15 times more precise than the current experimental result<\/em>. An experiment reaching the theoretical accuracy will probe mass scales up to the PeV range.   A later stage of PIONEER will measure the ultra-rare pion beta branch, which is the cleanest way to obtain Vud and thus test CKM unitarity. Throughout PIONEER data taking, we will also improve the experimental limits by an order of magnitude or more on a host of exotic decays probing for effects of heavy neutrinos and dark sector physics. Pioneer is approved at PSI and we have been engaging in beam tests, in local development of LYSO calorimetry, and in developing the overall simulation framework.<\/p>\n\n\n\n}

Recently completed:<\/strong>
<\/p>\n\n\n\n
MuLan<\/strong>: The Muon Lifetime Analysis (MuLan) experiment measures the positive muon lifetime, which provides the most precise determination of the Fermi coupling constant, one of the fundamental inputs to the standard model. Recent advances in theory have reduced the theoretical uncertainty on the Fermi coupling constant as calculated from the muon lifetime to a few tenths of a ppm. The remaining uncertainty on the Fermi constant is entirely experimental and is dominated by the uncertainty on the muon lifetime. The MuLan experiment employs an innovative pulsed beam, a symmetric detector, and modern data-taking methods to reduce the uncertainty on the muon lifetime to 1 ppm. This experiment took place at the Paul Scherrer Institute, Switzerland.   We completed data taking, analysis, and several well-deserved Ph.D. theses. We proudly achieved our exact proposal goal of 1.0 ppm final precision, measured twice in blind experiments. The Fermi constant, so obtained, has a precision of 0.5 ppm. **Our final paper is here<\/a>. The photo at the right shows some of us having prepared the soccer-ball-shaped detector for shipping to PSI.<\/p>\n\n\n\n**
MuCap<\/strong>: The goal of the MuCap experiment is a 1% precision measurement of the muon capture rate on the proton. From the capture rate, the pseudoscalar form factor, g<\/em>_{P<\/sub>, of the nucleon will be extracted with 7% precision. This basic quantity is predicted theoretically with high precision, but the experimental situation was quite controversial. The first round of our experiment led an unambiguous value for g<\/em>_{P<\/sub> and a strong confirmation of the chiral symmetry of QCD at low energies. The success was based on the novel idea of capturing negative muons in ultra-pure hydrogen gas (not liquid) and, equally importantly, instrumenting the stopping volume in the manner of a time projection chamber (TPC). My colleague Peter Kammel invented the idea and led the effort from its inception. Two MuCap Ph.D. students were the co-winners of the APS Nuclear Physics Dissertation prize for the earliest phase of the work, and two others have since graduated on refinements. The}}final paper<\/a> demonstrated that the theory is right, a very notable achievement.
<\/p>\n\n\n\n
<\/div>\n","protected":false},"excerpt":{"rendered":"
DAVID W. HERTZOG Arthur B. McDonald Distinguished Professor of Physics Director, Center for Experimental Nuclear Physics and Astrophysics Department of Physics   University of Washington Box 351560, Seattle WA 98195 (206) 543-0839hertzog@uw.edu Appointments: College of William and Mary Ph.D., Physics 1983 Carnegie-Mellon University   Research Associate 1983-86 University of Illinois Assistant Professor, Physics 1986-92 University of Illinois Associate, …<\/p>\n
Home<\/span> Read More »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-global-header-display":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"class_list":["post-24","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/comments?post=24"}],"version-history":[{"count":13,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24\/revisions"}],"predecessor-version":[{"id":51,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24\/revisions\/51"}],"wp:attachment":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/media?parent=24"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

College of William and Mary<\/a> <\/td>	Ph.D., Physics<\/td>	1983<\/td><\/tr>
Carnegie-Mellon University<\/a> <\/td>	Research Associate<\/td>	1983-86<\/td><\/tr>
University of Illinois<\/a><\/td>	Assistant Professor, Physics<\/td>	1986-92<\/td><\/tr>
University of Illinois<\/a><\/td>	Associate, Center for Advanced Study<\/td>	1990<\/td><\/tr>
University of Illinois<\/a><\/td>	Associate Professor, Physics<\/td>	1992-97<\/td><\/tr>
University of Illinois<\/a><\/td>	Professor, Physics<\/td>	1997-2010<\/td><\/tr>
University of Washington<\/a><\/td>	Professor, Physics<\/td>	2010-<\/td><\/tr>
University of Washington<\/a><\/td>	Director, CENPA<\/td>	2017-<\/td><\/tr>
University of Washington<\/a><\/td>	Arthur B. McDonald Distinguished Professor of Physics<\/td>	2020-<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Current Research: <\/strong>I lead a group that carries out high-precision experiments involving muons:<\/p>\n\n\n\n \n Muon g-2: Measurement of the muon anomaly to a precision of 0.140 ppb, which will be a sensitive test of the standard model. I was founding co-spokesperson and served through 2018. \u00a0I was Analysis Coordinator for the Run-1 results, published in 2021. The experiment is complete, achieving our full data goal and on track to reach our precision goal. The final analysis phase is in progress.<\/li>\n\n\n\n PIONEER:\u00a0 I am Spokesperson of a new collaboration with a program in rare pion decays that will test lepton flavor universality violation, search for exotics, and test CKM unitarity. This experiment is approved for running at PSI and we are actively engaged in hardware development and simulations at this time.<\/li>\n<\/ul>\n\n\n\n Previous and completed muon experiments:<\/strong><\/em><\/p>\n\n\n\n \n MuLan<\/strong>: a 1-ppm measurement of the muon lifetime, which determines the fundamental Fermi constant to sub-ppm precision. (Co-Spokesperson)<\/li>\n\n\n\n MuCap<\/strong>: a precision measurement of the rate of the semi-leptonic electroweak process \u03bc + p<\/em> –> n<\/em> + \u03bd_{\u03bc,<\/sub> which will determine the least-well-known of the charged weak form factors of the nucleon, the pseudoscalar g_{p<\/sub><\/em>, to 7%.<\/li>\n<\/ul>\n\n\n\nSee our Group’s Research page here<\/a><\/p>\n\n\n\n Honors and awards:<\/em><\/strong><\/p>\n\n\n\n \nTom W. Bonner Prize in Nuclear Physics (2022)<\/li>\n\n\n\n University Faculty Lecture, University of Washington (2022)<\/li>\n\n\n\n John Simon Guggenheim Foundation Fellow (2004)<\/li>\n\n\n\n Fellow, American Physical Society (2000)<\/li>\n\n\n\n University Scholar (2000)<\/li>\n\n\n\n BP Amoco Award for Innovation in Undergraduate Instruction, 2003<\/li>\n\n\n\n Amoco Award for Innovation in Undergraduate Education, 1997<\/li>\n\n\n\n W. Keck Foundation Award for Engineering Teaching Excellence, 1994<\/li>\n\n\n\n Everitt Award for Teaching Excellence, 1994<\/li>\n\n\n\nList of Excellent Teachers (at Illinois) , 18 semesters<\/li>\n<\/ul>\n\n\n\nInnovations in teaching and training<\/em><\/strong> (@Illinois) Developed new Modern Experimental Physics Laboratory<\/em> course featuring research-style data recording, analysis techniques, report writing, and oral presentations. Developed two-semester Introduction to Physics Research\/Senior Thesis<\/em> course sequence to prepare advanced undergraduates for physics careers. Served on the design teams for new introductory physics courses, which incorporate active-learning pedagogy. Designed and implemented all new laboratories for two semesters of algebra-based introductory physics courses. Wrote The Problem Solver for Physics 102 Discussion sections. Developed Discovery Room for Practical Physics: How Things Work<\/em> course. Co-teacher for several years in the College of Engineering Teaching College<\/em>, a mentoring program for new assistant professors. @Washington: Major effort to use SmartPhysics in 121 and 122 with a fully integrated \u201cflip the lecture\u201d approach. Many of my materials are being used by other faculty. <\/p>\n\n\n\n Science literacy and public outreach:<\/em><\/strong> Founded and ran for two years the Saturday Physics Honors Program<\/em> aimed at high school students, but also attended by the general public. Several invited talks to under-graduates and high-school physics teachers and public forums on muon g-2 experiments and more recently on The World’s Greatest Scientific Instruments<\/em>. Presentation to Seattle Technology Alliance on muon g-2; Scientific American podcast and other outreach related to first g-2 results in 2021<\/p>\n\n\n\n Ph.D. Students Supervised:<\/em><\/strong><\/p>\n\n\n\n Former students: R. Tayloe, S.A. Hughes, P.E. Reimer, J. Ritter, T. Jones, B. Bunker, F.E. Gray, C. Polly, D.B Chitwood, D. Webber, J. Crnkovic, B. Kiburg* , N. Froemming, M. Smith, A. Fienberg, J. Hempstead, H. Binney; Current students: J. Labounty, O. Beesley<\/p>\n\n\n\n *co-supervised with P. Kammel;<\/p>\n\n\n\n Postdoctoral Fellows Supervised:<\/em><\/strong><\/p>\n\n\n\n Former: P.G. Harris, S.A. Sekykh, G. Onderwater, F. Mulhauser, C. Ozben, R. McNabb, P. Winter, S. Kizilgul, P. Alonzi, J. Kaspar, K. Khaw, Z. Hodge; Current: C. Claessens, P. Schwendimann, S. Braun, Josh LaBounty<\/p>\n\n\n\n Some special papers <\/strong>of interest:<\/strong><\/p>\n\n\n\nSelected papers, but see this link for current Inspire list<\/a><\/strong>; Google Scholar List<\/strong><\/a><\/p>\n\n\n\n Publications related to the results from our Fermilab Muon g-2 Experiment: (and some selected press<\/a> from the 2021 release)<\/p>\n\n\n\n \nMeasurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm; (Muon g-2 Collaboration) D.P. Aguillard et al; Phys.Rev.Lett. 131 (2023) 16, 161802.<\/li>\n\n\n\n Detailed Report on the Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm; (Muon g-2 Collaboration) D.P. Aguillard et al.,\u00a0 (Feb 23, 2024) Phys.Rev.D 110 (2024) 3, 032009.<\/li>\n\n\n\n Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm; (Muon g-2 Collaboration) B. Abi et al. Phys.Rev.Lett. 126 (2021) 14, 141801.<\/li>\n\n\n\n Magnetic Field Measurement and Analysis for the Muon g-2 Experiment at Fermilab; (Muon g-2 Collaboration) T. Albahri et al. Phys.Rev.A 103 (2021) 4, 042208<\/li>\n\n\n\n Measurement of the anomalous precession frequency of the muon in the Fermilab Muon g-2 experiment; (Muon g-2 Collaboration) T. Albahri et al; Phys.Rev.D 103 (2021) 7, 072002.<\/li>\n\n\n\nBeam dynamics corrections to the Run-1 measurement of the muon anomalous magnetic moment at Fermilab; (Muon g-2 Collaboration) T. Albahri et al; Phys.Rev.Accel.Beams 24, (2021) 044002.<\/li>\n<\/ol>\n\n\n\nReview papers<\/strong><\/p>\n\n\n\n\nPrecision Muon Physics<\/em>, T.P. Gorringe and D.W. Hertzog, Prog. Part. Nucl. Phys. 84 (2015) 73-123.<\/li>\n\n\n\n Low-energy precision test of the standard model:\u00a0 a snapshot,<\/em>\u00a0 D.W. Hertzog, Annalen der Physik, (2015)<\/li>\n\n\n\n The Brookhaven Muon Anomalous Magnetic Moment Experiment,<\/em> David W. Hertzog and William M. Morse, Annu. Rev. Nucl. Part. Sci. 2004. 54:141-74.<\/li>\n\n\n\nD. W. Hertzog. Muons: Particles of the moment. Physics World 17 N3, 29-34 (2004)<\/li>\n<\/ol>\n\n\n\n \ufeff<\/p><\/p>\n\n\n\n Some Technical Papers on Calorimetry<\/strong><\/p>\n\n\n\n\nMeasurements of a LYSO crystal array from threshold to 100 MeV; O. Beesley et al.; e-Print: 2409.14691 [physics.ins-det]<\/li>\n\n\n\n Studies of an array of PbF_{2<\/sub> Cherenkov crystals with large-area SiPM readout, A.T. Fienberg et al., Nucl. Instrum. Meth. A783 (2015) 12-21.Some Technical Papers on Calorimetry<\/li>\n\n\n\n} Design and performance of SiPM-based readout of PbF2 crystals for high-rate, precision timing applications, J. Kaspar et al., JINST 12 (2017) no.01, P01009.<\/li>\n\n\n\n Performance of the Muon g-2 calorimeter and readout systems measured with test beam data; K.S. Khaw et al.; Nucl.Instrum.Meth.A 945 (2019) 162558.<\/li>\n\n\n\n S. A. Sedykh, et al. Electromagnetic calorimeters for the BNL muon (g-2) experiment. Nucl. Instrum. & Meth. A 455, 346-360 (2000).<\/li>\n\n\n\nD. W. Hertzog, P. T. Debevec, R. A. Eisenstein, M. A. Graham, S. A. Hughes, P. E. Reimer, and R. L. Tayloe. A high-resolution lead\/scintillating fiber electromagnetic calorimeter. Nucl. Instrum. & Meth. A 294, 446-458 (1990)<\/li>\n<\/ol>\n\n\n\nDescription of Current Research<\/strong><\/p>\n\n\n\nMost of our group at the Elba, 2019 Muon g-2 Collaboration Meeting<\/figcaption><\/figure>\n\n\n\n <\/p>\n\n\n\n Muon g-<\/em>2<\/strong>: Our group is engaged in a sub-ppm measurement of the muon’s anomalous magnetic moment (g-2).<\/em> The results of this experiment, when compared with precise theoretical calculations, are capable of revealing physics beyond the Standard Model attributed to SUSY particles of high mass, to structured intermediate vector bosons, or to substructure of the muon itself.\u00a0 Our final measurement, from the Brookhaven E821 Experiment, was more than 3 standard deviations from the current (2022) Standard Model expectation and the result has caused a significant buzz in the theoretical community. Our new experiment at Fermilab has been taking data through 6 years, acquiring more than 20 times the data obtained at BNL. Our first results — based on about 6% of the expected total — confirmed the BNL value and, when averaged together, increased the tension with the SM to more than 4 standard deviations. Our Run 2\/3 results further confirmed the measurement with increased precision. However, the comparison with the SM Theory is now a bit fuzzy given latest Lattice calculations and a new HVP measurement from CMD3. Until this is resolved, we can’t fully interpret the results. Meanwhile, we are pushing hard complete the Run 4\/5\/6 data analysies, representing 75% of our overall data set. Stay tuned for that soon in 2025.\u00a0 <\/p>\n\n\n\n PIONEER <\/strong>is a next-generation, rare-pion decay experiment that will take place at the Paul Scherrer Institute (PSI) in Switzerland. There are three main physics thrusts. The first priority will be the world\u2019s most sensitivity test of lepton flavor universality (LFU). It is strongly motivated by several inconsistencies between Standard Model (SM) predictions and data pointing towards the potential violation of LFU. The program will probe non-SM explanations of these anomalies through sensitivity to quantum effects of new particles, even if their masses are at very high scales. Measurement of the charged-pion branching ratio of electrons vs. muons is extremely sensitive to a wide variety of new physics effects. At present, the SM prediction is known to 1 part in 10^{4<\/sup>, which is 15 times more precise than the current experimental result<\/em>. An experiment reaching the theoretical accuracy will probe mass scales up to the PeV range. A later stage of PIONEER will measure the ultra-rare pion beta branch, which is the cleanest way to obtain Vud and thus test CKM unitarity. Throughout PIONEER data taking, we will also improve the experimental limits by an order of magnitude or more on a host of exotic decays probing for effects of heavy neutrinos and dark sector physics. Pioneer is approved at PSI and we have been engaging in beam tests, in local development of LYSO calorimetry, and in developing the overall simulation framework.<\/p>\n\n\n\n} Recently completed:<\/strong> <\/p>\n\n\n\nMuLan<\/strong>: The Muon Lifetime Analysis (MuLan) experiment measures the positive muon lifetime, which provides the most precise determination of the Fermi coupling constant, one of the fundamental inputs to the standard model. Recent advances in theory have reduced the theoretical uncertainty on the Fermi coupling constant as calculated from the muon lifetime to a few tenths of a ppm. The remaining uncertainty on the Fermi constant is entirely experimental and is dominated by the uncertainty on the muon lifetime. The MuLan experiment employs an innovative pulsed beam, a symmetric detector, and modern data-taking methods to reduce the uncertainty on the muon lifetime to 1 ppm. This experiment took place at the Paul Scherrer Institute, Switzerland. We completed data taking, analysis, and several well-deserved Ph.D. theses. We proudly achieved our exact proposal goal of 1.0 ppm final precision, measured twice in blind experiments. The Fermi constant, so obtained, has a precision of 0.5 ppm. Our final paper is here<\/a>. The photo at the right shows some of us having prepared the soccer-ball-shaped detector for shipping to PSI.<\/p>\n\n\n\n MuCap<\/strong>: The goal of the MuCap experiment is a 1% precision measurement of the muon capture rate on the proton. From the capture rate, the pseudoscalar form factor, g<\/em>_{P<\/sub>, of the nucleon will be extracted with 7% precision. This basic quantity is predicted theoretically with high precision, but the experimental situation was quite controversial. The first round of our experiment led an unambiguous value for g<\/em>_{P<\/sub> and a strong confirmation of the chiral symmetry of QCD at low energies. The success was based on the novel idea of capturing negative muons in ultra-pure hydrogen gas (not liquid) and, equally importantly, instrumenting the stopping volume in the manner of a time projection chamber (TPC). My colleague Peter Kammel invented the idea and led the effort from its inception. Two MuCap Ph.D. students were the co-winners of the APS Nuclear Physics Dissertation prize for the earliest phase of the work, and two others have since graduated on refinements. The}}final paper<\/a> demonstrated that the theory is right, a very notable achievement. <\/p>\n\n\n\n <\/div>\n","protected":false},"excerpt":{"rendered":"DAVID W. HERTZOG Arthur B. McDonald Distinguished Professor of Physics Director, Center for Experimental Nuclear Physics and Astrophysics Department of Physics University of Washington Box 351560, Seattle WA 98195 (206) 543-0839hertzog@uw.edu Appointments: College of William and Mary Ph.D., Physics 1983 Carnegie-Mellon University Research Associate 1983-86 University of Illinois Assistant Professor, Physics 1986-92 University of Illinois Associate, …<\/p>\n Home<\/span> Read More »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-global-header-display":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","footnotes":""},"class_list":["post-24","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/comments?post=24"}],"version-history":[{"count":13,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24\/revisions"}],"predecessor-version":[{"id":51,"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/pages\/24\/revisions\/51"}],"wp:attachment":[{"href":"http:\/\/faculty.washington.edu\/hertzog\/wp-json\/wp\/v2\/media?parent=24"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}}}