Letter of intent: a muon to electron conversion experiment at Fermilab

Abstract

Abstract:We are writing this letter to express our interest in pursuing an experiment at Fermilab to search for neutrinoless conversion of muons into electrons in the field of a nucleus, which is a lepton flavor-violating (LFV)

Pascalutsa-Vanderhaeghen light-by-light sum rule from photon-photon collisions

“…Thus the Born approximation is there poorer. 1 The physical cross-sections for π + π − and π − π 0 are related to integrals of the sums of the modulus squared of the helicity amplitudes of definite isospin and so involve interferences of isospin amplitudes. Only the sum of the π + π − and π 0 π 0 cross-sections (where the interference cancels) is simply related to I,λ=0,2 σ I λ .…”

“…There is keen interest in improving our understanding of light-by-light scattering as an essential ingredient of calculations of hadronic contributions to the anomalous magnetic moment of the muon in preparation for planned experiments at Fermilab [1] and J-PARC [2]. An essential component of this are tests of the theoretical framework by the scattering of essentially real photons, as an anchor for modeling scattering with photons of virtuality up to 2 GeV 2 that control the multi-loop structure of hadronic light-by-light scattering.…”

Antimatter, Lorentz Symmetry, and Gravity

“…(42), methods of obtaining interesting sensitivities to SME coefficients are developed. Some initial constraints are then placed using existing results from Brookhaven National Laboratory (BNL) [22] and CERN [23], on which 5 fold improvements are possible in upcoming experiments at the Japan Proton Accelerator Research Complex (J-PARC) [24] and at the Fermi National Accelerator Laboratory (Fermilab) [25]. The first method discussed involves comparison of the muon and antimuon anomaly frequencies using different schemes to separate constraints on CPT-odd and even coefficients.…”

Charged lepton flavor violation in the semi-constrained NMSSM with right-handed neutrinos

“…The current limits are B μe (Ti) < 4.3 × 10 −12 , B μe (Au) < 7 × 10 −13 [1]. The near future experiments are the COMET experiment at J-PARC [31], the Mu2e experiment at FNAL [32], and the PRISM/PRIME experiment at J-PARC [33], which are expected to improve the bounds to B μe (Al) ∼ 6 × 10 −17 [34], B μe (Al) ∼ 6 × 10 −17 [35], B μe (Al) ∼ 10 −18 [33], respectively. Since the R(Z ) factors for these experiments are R ∼ 0.0025 for Al and R ∼ 0.0040 for Ti [30], these experiments are expected to go beyond the corresponding limit of the μ → eγ decay by 1.5 ∼ 3 orders of magnitude, and this will be very useful to probe broader parameter region of new physics.…”