Fluorinated cyclothiaphosphazenes:Synthesis, structure and reactivity

Reaction of chlorocyclothiaphosphazenes NPCl2(NSOX)(2) (X = Cl, Ph) and (NPCl2)(2)NSOX (X = Cl, F, Ph) with KSO2F in bulk leads to fluorination at the phosphorus centers. The substitution reaction follows a geminal pattern. Reactions of trans-NPF2(NSOPh)(2) with Grignard reagents RMgX (R = Me, (t)Bu) show substitution of fluorine by alkyl groups to be a slow process. The more reactive PhMgBr gives an acceptable reaction rate and good yields. Organolithium reagents offer organo-substituted cyclothiaphosphazenes in low to moderate yields, depending on the reagent used. Crystals of cis-NPF2(NSOPh)(2) are monoclinic, space group P2(1)/n, with a = 13.665(7) Angstrom, b = 10.676(1) Angstrom, c = 9.897(3) Angstrom, beta = 90.55(3)degrees, V = 1443.8(9) Angstrom(3), and Z = 4. The final R and wR values are 0.034 and 0.043, respectively. The PN and SN bond lengths vary from 1.571(2) to 1.590(2) Angstrom

Mu2e Run I Sensitivity Projections for the Neutrinoless mu(-) -> e(-) Conversion Search in Aluminum

The Mu2e experiment at Fermilab will search for the neutrinoless μ−→e− conversion in the field of an aluminum nucleus. The Mu2e data-taking plan assumes two running periods, Run I and Run II, separated by an approximately two-year-long shutdown. This paper presents an estimate of the expected Mu2e Run I search sensitivity and includes a detailed discussion of the background sources, uncertainties of their prediction, analysis procedures, and the optimization of the experimental sensitivity. The expected Run I 5σ discovery sensitivity is Rμe=1.2×10−15, with a total expected background of 0.11±0.03 events. In the absence of a signal, the expected upper limit is Rμe&lt;6.2×10−16 at 90% CL. This represents a three order of magnitude improvement over the current experimental limit of Rμe&lt;7×10−13 at 90% CL set by the SINDRUM II experiment.</jats:p