G-2 experiment A proposal to measure the muon anomalous magnetic moment to 0.14 ppm precision Experiment at Fermilab Built on the foundation of E821, with important new strength added

New (G-2) Collaboration: R.M. Carey, K.R. Lynch, J.P. Miller, B.L. Roberts, W.M. Morse, Y.K. Semertzidis, V.P. Druzhinin, B.I. Khazin, I.A. Koop, I. Logashenko, S.I. Redin, Y.M. Shatunov, Y. Orlov, R.M. Talman, B. Casey, J. Johnstone, D. Harding, A. Klebaner, A. Leveling, J-F. Ostiguy, N. Mokhov, D. Neuffer, M. Popovic, S. Strigonov, M. Syphers, G. Velev, S. Werkema, F. Happacher, G. Venanzoni, P. Debevec, M. Grosse-Perdekamp, D.W. Hertzog, P. Kammel, C. Polly, K.L. Giovanetti, K. Jungmann, C.J.G. Onderwater, N. Saito, C. Crawford, R. Fatemi, T.P. Gorringe, W. Korsch, B. Plaster, V. Tishchenko, D. Kawall, T. Chupp, C. Ankenbrandt, M.A Cummings, R.P. Johnson, C. Yoshikawa, Andre de Gouvea, T. Itahashi, Y. Kuno, G.D. Alkhazov, V.L. Golovtsov, P.V. Neustroev, L.N. Uvarov, A.A. Vasilyev, A.A. Vorobyov, M.B. Zhalov, F. Gray, D. Stockinger, S. Baeler, M. Bychkov, E. Frlez, and D. Pocanic The New (G - 2) Experiment: A Proposal to Measure the Muon Anomalous Magnetic Moment to ± 0.14 ppm Precision

Дирак : для S=1/2= 2 LO QCD (Schwinger): =

a = (g – 2)/2 is non-zero because of virtual loops, which can be calculated very precisely B QED Z Weak Had LbL Had VP Known wellTheoretical work ongoing a = 51 x

A consistent set of measurements with a steady improvement in precision. Experiment

Where we are and where we are going Present Status: Experimental uncertainty = 63 x (0.54 ppm) 0.46 ppm statistical (limit was counts) 0.28 ppm systematic Theory uncertainty = 51 x (0.44 ppm) Leads to a (Expt – Thy) = 295 ± 81 x Expected situation after experiment: Experimental uncertainty: x ppm statistical 21x the E821 events 0.1 ppm systematic overall Theory uncertainty: x Future: a (Expt – Thy) = xx ± 34 x (If xx remains 295, the deviation from zero would be close to 9σ)

Precise knowledge of a will aid in discrimination between a wide variety of standard model extensions UED models (1D) typically predict tiny effects –Incompatible with a a of ~ 300 x SUSY models – there are many – predict a contributions of about the observed magnitude for a The Uninvented – perhaps most importantly, sets a stringent experimental constraint for any new models

Muon g-2 is a powerful discriminator no matter where the final value lands SPS Definitions Universal Extra Dimensions 1D Illustration of resolving power among SUSY models Model UED Future? Present Models

MSSM –tan poorly determined by collider * SPS1a is a ``Typical '' mSUGRA point with intermediate tan = 10 g-2 is complementary to the LHC

Another goal of the G-2 experiment is to improve the muon EDM limit by up to a factor of 100 and make a higher-precision test of Lorentz and CPT violation

The measurement principle

Δω ω a = ω s – ω c = a μ (qB/m) g = 2 a μ =0 ω s = ω c, Δω = 0. g 2 ω s ω c, Δω/ω c = γ(Δg/g) = γa μ In our case, γ 30, a μ 0.001, Δω/ω c 0.03 γ 30 ! p μ = GeV/c

The existing storage muon ring that will be relocated to FNAL

8GeV protons from the Booster Antiproton target 3.1 GeV/c positive pions 900 m pion decay line (λ decay = 173 m) Polarized muons are injected in the storage ring Positrons from the muon decay are registered (μ + e + + ν e + ν μ ) The frequency of the oscillations in the intensity of the registered positrons is used to determine ω a

Momentum Spin e

В системе центра масс мюона позитроны с большей энергией испускаются преимущественно в направлении спина. Т.к. спин прецессирует по отношению к направлению движения мюона, возникают биения интенсивности позитронов, испускаемых вперед. Total number of events in G-2 - ~1.8 x (21 times more than in E821)

(1) Precession frequency (2) Magnetic field map (3) Muon space distribution The measurement involves determining 3 quantities to high precision

Осцилляции интенсивности испускаемых позитронов в вертикальной плоскости позволяют измерить EDM мюона (дать ограничения на величину EDM) Е821

The Storage Ring exists and will be moved to FNAL incoming muons Quads

Electrostatic quadrupoles

Segmenting detectors will reduce pileup. New W-SciFi calorimeter 20-fold segmentation for PMTs 0.7 cm X 0 10% resolution at 2 GeV R&D option, 35-fold segmentation using onboard SiPM Low E High E 24 calorimeter stations

Straw tube detectors ?

Micro-cathode strip chambers

Technically driven schedule data taking