Precision Muon Experiments

We propose continuing research in experimental muon physics involving the muon g-2 experiment at Fermilab and the MuSun experiment at Paul Scherrer Institute. The g-2 experiment will determine the muon anomalous magnetic moment enabling an important test of Standard Model and the MuSun experiment will determine the muonic deuterium doublet capture rate enabling an important study of weak nuclear interactions. Intellectual merit. The Fermilab g-2 experiment will measure the muon anomalous magnetic moment aì to ±140 ppb, a four-fold improvement over BNL Expt. 821. The measurement addresses the longstanding 3.5 discrepancy between the BNL Expt. 821 measurement and the Standard Model prediction. It represents a key test of the standard model and has unique sensitivity to new particle and interactions beyond the standard model The PI is co-leader of the detector team and the L3 manager for the data acquisition system. In particular, the PI’s group – the PI, post-doctoral research Wes Gohn, graduate student Mike Weaver with Departmental electronics engineering and computing support – are responsible for the 18 GByte/sec data readout, GPU-based data processing, and multicore-CPU event building for the g-2 data acquisition system. The g-2 experiment was approved by FNAL in 12/2009, received DOE CD-0 approval in 9/2012, DOE CD-1 approval in 12/2013, and underwent a successful DOE CD-2/3 review in 7/2014. The BNL muon storage ring was relocated to FNAL from BNL in 2013 and is now housed in the new MC-1 experiment hall for the muon g-2 experiment. The DAQ development work will continue through 2015 with implementation and commissioning during 2015–16 and data taking beginning in 2017. In MuSun experiment we will measure the u-d>nnv doublet capture rate to ±1.5%. The measurement addresses a longstanding discrepancy among earlier measurements of ì.d capture and will determine the two-body weak nuclear axial current. The two-body contribution to the weak axial current is important for understanding such processes as pp thermonuclear fusion, cross sections fir neutrino experiments, and ordinary and double -decay. The measurement provides an important yardstick for recent developments in low energy effective field theories. In MuSun the PI’s group have been responsible for the installation, operation and analysis of the neutron detector array as well as data acquisition. The Kentucky MuSun group comprises the PI, post-doc Wes Gohn, and graduate students Kres Neely and Nandita Raha. Ms. Raha is completing her dissertation from the 2011 MuSun production run on measurements of atomic/molecular kinetics parameters using the time spectra of the ddì fusion neutrons. Mr. Kres Neely will complete his dissertation from the 2013 MuSun production runs on studies of capture neutrons from ì.d atoms and surrounding materials. The MuSun experiment was commissioned during the period 2011-12 and major data taking runs were conducted in 2013 and 2014 and planned for 2015. The MuSun activities of the PI’s group during the proposed project are data analysis and simulation worl as well as 2015 data taking. Broader impact. The planned research includes substantial broader impact. For example, the PI will continue his efforts to: involve high school students, computer science and physics majors, physics graduate students in research activities, advance the quality and diversity of graduate studies in Physics and Astronomy at UK as DGS, conduct outreach to local middle and high Schools, and develop online and in-class materials for general physics instruction. Our activities in data acquisition and data analysis involve students in many aspects of modern computing such as parallel processing, GPU processing, network configuration, telecommunications hardware, and programming / scripting languages. Moreover, our research involving precision measurements of fundamental properties and elementary interactions will determine textbook quantities and has broad interest spanning nuclear, particle and astrophysics. 1