Creatine excretion in diabetes mellitus

Dupuytren's contracture is a common condition in diabetes mellitus. One of the authors has described 120 of these cases among 381 diabetics in the older age group. Steinberg has stated that in Dupuytren's contracture the creatine excretion in the urine is increased and suggests that both in this condition and in fibrositis there is an abnormality in tissue metabolism. He found that the total amount of creatine excreted per 24 hours in cases of primary fibrositis was 264-918 mg. (in this group he included Dupuytren's contracture). In 12 out of 15 cases it was over 300 mg. per 24 hours. In view of this suggestion and the frequency of Dupuytren's contracture in diabetes, it was decided to investigate the creatine excretion in a series of diabetic patients

Renormalons and confinement

We compute the renormalon ambiguity of the static potential, in the limit of a large number of flavors. An extrapolation of the QED result to QCD implies that the large distance behavior of the quark potential is arbitrary in perturbation theory, as there are an infinite number of prescriptions to assign. The shape of the potential at large distances is not only affected by the renormalon pole closest to the origin of the Borel plane, but a resummation of all renormalon contributions is required. In particular, confinement can be accommodated, but it is not explained. At short distances there is no indication of a linear term in the potential.Comment: 7 pages revtex; major changes: list of authors corrected, title, abstract, body of paper changed

Lattice gauge theory: A retrospective

I discuss some of the historical circumstances that drove us to use the lattice as a non-perturbative regulator. This approach has had immense success, convincingly demonstrating quark confinement and obtaining crucial properties of the strong interactions from first principles. I wrap up with some challenges for the future.Comment: Lattice 2000 (Plenary), 9 pages, 7 figure

Can a strongly interacting Higgs boson rescue SU(5)?

Renormalization group analyses show that the three running gauge coupling constants of the Standard Model do not become equal at any energy scale. These analyses have not included any effects of the Higgs boson's self-interaction. In this paper, I examine whether these effects can modify this conclusion.Comment: 8 pages (plus 4 postscript figures

The four-loop beta-function in Quantum Chromodynamics

We present the analytical calculation of the four-loop QCD beta-function within the minimal subtraction scheme.Comment: 9 pages, Latex, 1 figure, uses axodraw.st

Comment on studying the corrections to factorization in B -> D(*) X

We propose studying the mechanism of factorization in exclusive decays of the form B->D(*)X by examining the differential decay rate as a function of the invariant mass of the light hadronic state X. If factorization works primarily due to the large N_c limit then its accuracy is not expected to decrease as the X invariant mass increases. However, if factorization is mostly a consequence of perturbative QCD then the corrections should grow with the X invariant mass. Combining data for hadronic tau decays and semileptonic B decays allows tests of factorization to be made for a variety of final states. We discuss the examples of B->D^*\pi^+\pi^-\pi^-\pi^0 and B->D^*\omega\pi^-. The mode B->D^*\omega\pi^- will allow a precision study of the dependence of the corrections to factorization on the invariant mass of the light hadronic state.Comment: 7 pages, minor clarifications to tex

Higher Order 1/m1/m Corrections at Zero Recoil

The general structure of the $1/m$ corrections at zero recoil is studied. The relevant matrix elements are forward matrix elements of local higher dimensional operators and their time ordered products with higher order terms from the Lagrangian. These matrix elements may be classified in a simple way and the analysis at the non recoil point for the form factor of heavy quark currents simplifies drastically. The second order recoil corrections to the form factor $h_{A1}$ of the axial vector current, relevant for the $|V_{cb}|$ determination from $B \to D^*$ decays, are estimated to be $-5\% < h_{A1} - 1 < 0$.Comment: LaTeX, 25 pages, one figure, appended after \end{document} as uu-encoded and compressed eps file, uses epsf, CERN-TH.7162/9

Unitarity of Quantum Theory and Closed Time-Like Curves

Interacting quantum fields on spacetimes containing regions of closed timelike curves (CTCs) are subject to a non-unitary evolution $X$. Recently, a prescription has been proposed, which restores unitarity of the evolution by modifying the inner product on the final Hilbert space. We give a rigorous description of this proposal and note an operational problem which arises when one considers the composition of two or more non-unitary evolutions. We propose an alternative method by which unitarity of the evolution may be regained, by extending $X$ to a unitary evolution on a larger (possibly indefinite) inner product space. The proposal removes the ambiguity noted by Jacobson in assigning expectation values to observables localised in regions spacelike separated from the CTC region. We comment on the physical significance of the possible indefiniteness of the inner product introduced in our proposal.Comment: 13 pages, LaTeX. Final revised paper to be published in Phys Rev D. Some changes are made to expand our discussion of Anderson's Proposal for restoring unitarit

QCD Factorization for B→ππB\to\pi\pi Decays: Strong Phases and CP Violation in the Heavy Quark Limit

We show that, in the heavy quark limit, the hadronic matrix elements that enter $B$ meson decays into two light mesons can be computed from first principles, including `non-factorizable' strong interaction corrections, and expressed in terms of form factors and meson light-cone distribution amplitudes. The conventional factorization result follows in the limit when both power corrections in $1/m_b$ and radiative corrections in $\alpha_s$ are neglected. We compute the order-$\alpha_s$ corrections to the decays $B_d\to\pi^+\pi^-$, $B_d\to\pi^0\pi^0$ and $B^+\to\pi^+\pi^0$ in the heavy quark limit and briefly discuss the phenomenological implications for the branching ratios, strong phases and CP violation.Comment: 6 pages, 1 figur

Renormalization group dependence of the QCD coupling

The general relation between the standard expansion coefficients and the beta function for the QCD coupling is exactly derived in a mathematically strict way. It is accordingly found that an infinite number of logarithmic terms are lost in the standard expansion with a finite order, and these lost terms can be given in a closed form. Numerical calculations, by a new matching-invariant coupling with the corresponding beta function to four-loop level, show that the new expansion converges much faster.Comment: 6 pages, 2 figures, RevTex4 styl