Refined gluino and squark pole masses beyond leading order

The physical pole and running masses of squarks and gluinos have recently been related at two-loop order in a mass-independent renormalization scheme. I propose a general method for improvement of such formulas, and argue that better accuracy results. The improved version gives an imaginary part of the pole mass that agrees exactly with the direct calculation of the physical width at next-to-leading order. I also find the leading three-loop contributions to the gluino pole mass in the case that squarks are heavier, using effective field theory and renormalization group methods. The efficacy of these improvements for the gluino and squarks is illustrated with numerical examples. Some necessary three-loop results for gauge coupling and fermion mass beta functions and pole masses in theories with more than one type of fermion representation, which are not directly accessible from the published literature, are presented in an Appendix.Comment: 14 pages. v2: typos in equations (A.11), (A.17), and (A.18) fixe

Two-loop scalar self-energies and pole masses in a general renormalizable theory with massless gauge bosons

I present the two-loop self-energy functions for scalar bosons in a general renormalizable theory, within the approximation that vector bosons are treated as massless or equivalently that gauge symmetries are unbroken. This enables the computation of the two-loop physical pole masses of scalar particles in that approximation. The calculations are done simultaneously in the mass-independent \bar{MS}, \bar{DR}, and \bar{DR}' renormalization schemes, and with arbitrary covariant gauge fixing. As an example, I present the two-loop SUSYQCD corrections to squark masses, which can increase the known one-loop results by of order one percent. More generally, it is now straightforward to implement all two-loop sfermion pole mass computations in supersymmetry using the results given here, neglecting only the electroweak vector boson masses compared to the superpartner masses in the two-loop parts.Comment: 16 pages, 4 figures. v2: typo in eq. (5.30) fixe

Numerical evaluation of the general massive 2-loop 4-denominator self-mass master integral from differential equations

The differential equation in the external invariant p^2 satisfied by the master integral of the general massive 2-loop 4-denominator self-mass diagram is exploited and the expansion of the master integral at p^2=0 is obtained analytically. The system composed by this differential equation with those of the master integrals related to the general massive 2-loop sunrise diagram is numerically solved by the Runge-Kutta method in the complex p^2 plane. A numerical method to obtain results for values of p^2 at and close to thresholds and pseudo-thresholds is discussed in details.Comment: Latex, 20 pages, 7 figure

Strong and Yukawa two-loop contributions to Higgs scalar boson self-energies and pole masses in supersymmetry

I present results for the two-loop self-energy functions for neutral and charged Higgs scalar bosons in minimal supersymmetry. The contributions given here include all terms involving the QCD coupling, and those following from Feynman diagrams involving Yukawa couplings and scalar interactions that do not vanish as the electroweak gauge couplings are turned off. The impact of these contributions on the computation of pole masses of the neutral and charged Higgs scalar bosons is studied in a few examples.Comment: 23 pages, 9 figures, revtex4. New paragraph in introduction, more explanation of Figure

Master integrals for the two-loop light fermion contributions to gg→Hgg \to H and H→γγH \to \gamma\gamma

We give the analytic expressions of the eight master integrals entering our previous computation of two-loop light fermion contributions to $gg \to H$ and $H \to \gamma\gamma$. The results are expressed in terms of generalized harmonic polylogarithms with maximum weight four included.Comment: 9 pages, 6 figure

Neuroconductor: an R platform for medical imaging analysis

Neuroconductor (https://neuroconductor.org) is an open-source platform for rapid testing and dissemination of reproducible computational imaging software. The goals of the project are to: (i) provide a centralized repository of R software dedicated to image analysis, (ii) disseminate software updates quickly, (iii) train a large, diverse community of scientists using detailed tutorials and short courses, (iv) increase software quality via automatic and manual quality controls, and (v) promote reproducibility of image data analysis. Based on the programming language R (https://www.r-project.org/), Neuroconductor starts with 51 inter-operable packages that cover multiple areas of imaging including visualization, data processing and storage, and statistical inference. Neuroconductor accepts new R package submissions, which are subject to a formal review and continuous automated testing. We provide a description of the purpose of Neuroconductor and the user and developer experience

A FLEXIBLE GENERAL CLASS OF MARGINAL AND CONDITIONAL RANDOM INTERCEPT MODELS FOR BINARY OUTCOMES USING MIXTURES OF NORMALS

Random intercept models for binary data are useful tools for addressing between subject heterogeneity. Unlike linear models, the non-linearity of link functions used for binary data force a distinction between marginal and conditional interpretations. This distinction is blurred in probit models with a normally distributed random intercept because the resulting model implies a probit marginal link as well. That is, this model is closed in the sense that the distribution associated with the marginal and conditional link functions and the random effect distribution are all of the same family. In this manuscript we explore another family of random intercept models with this property. In particular, we consider instances when the distributions associated with the conditional and marginal link functions and the random effect distribution are mixtures of normals. We show that this flexible family of models is related to several others presented in the literature. Moreover, we also show that this family of models offers considerable computational benefits. A diverse series of examples illustrates the wide applicability of the approach

Two-Loop Bhabha Scattering in QED

In the context of pure QED, we obtain analytic expressions for the contributions to the Bhabha scattering differential cross section at order alpha^4 which originate from the interference of two-loop photonic vertices with tree-level diagrams and from the interference of one-loop photonic diagrams amongst themselves. The ultraviolet renormalization is carried out. The IR-divergent soft-photon emission corrections are evaluated and added to the virtual cross section. The cross section obtained in this manner is valid for on-shell electrons and positrons of finite mass, and for arbitrary values of the center of mass energy and momentum transfer. We provide the expansion of our results in powers of the electron mass, and we compare them with the corresponding expansion of the complete order alpha^4 photonic cross section, recently obtained in hep-ph/0501120. As a by-product, we obtain the contribution to the Bhabha scattering differential cross section of the interference of the two-loop photonic boxes with the tree-level diagrams, up to terms suppressed by positive powers of the electron mass. We evaluate numerically the various contributions to the cross section, paying particular attention to the comparison between exact and expanded results.Comment: 35 pages, 18 figure