The B --> pi form factor from light-cone sum rules in soft-collinear effective theory

Recently, we have derived light-cone sum rules for exclusive B-meson decays into light energetic hadrons from correlation functions within soft-collinear effective theory. In these sum rules the short-distance scale refers to ``hard-collinear'' interactions with virtualities of order \Lambda_{QCD} m_b. Hard scales (related to virtualities of order m_b^2) are integrated out and enter via external coefficient functions in the sum rule. Soft dynamics is encoded in light-cone distribution amplitudes for the B-meson, which describe both the factorizable and non-factorizable contributions to exclusive B-meson decay amplitudes. Factorization of the correlation function has been verified to one-loop accuracy. Thus, a systematic separation of hard, hard-collinear, and soft dynamics in the heavy-quark limit is possible.Comment: 5 pages, one figur

Erratum to: "Light-cone sum rules in soft-collinear effective theory" [Nucl. Phys. B 733 (2006) 1–30]

n/

On the contribution of the electromagnetic dipole operator O7{\cal O}_7 to the Bˉs→μ+μ−\bar B_s \to \mu^+\mu^- decay amplitude

We construct a factorization theorem that allows to systematically include QCD corrections to the contribution of the electromagnetic dipole operator in the effective weak Hamiltonian to the $\bar B_s \to \mu^+\mu^-$ decay amplitude. We first rederive the known result for the leading-order QED box diagram, which features a double-logarithmic enhancement associated to the different rapidities of the light quark in the $\bar B_s$ meson and the energetic muons in the final state. We provide a detailed analysis of the cancellation of the related endpoint divergences appearing in individual momentum regions, and show how the rapidity logarithms can be isolated by suitable subtractions applied to the corresponding bare factorization theorem. This allows us to include in a straightforward manner the QCD corrections arising from the renormalization-group running of the hard matching coefficient of the electromagnetic dipole operator in soft-collinear effective theory, the hard-collinear scattering kernel, and the $B_s$-meson distribution amplitude. Focusing on the contribution from the double endpoint logarithms, we derive a compact formula that resums the leading-logarithmic QCD corrections.Comment: 33 pages, 3 figure

SCET sum rules for B->P and B->V transition form factors

We investigate sum rules for heavy-to-light transition form factors at large recoil derived from correlation functions with interpolating currents for light pseudoscalar or vector fields in soft-collinear effective theory (SCET). We consider both, factorizable and non-factorizable contributions at leading power in the Lambda/m_b expansion and to first order in the strong coupling constant alpha_s, neglecting contributions from 3-particle distribution amplitudes in the B-meson. We pay particular attention to various sources of parametric and systematic uncertainties. We also discuss certain form factor ratios where part of the hadronic uncertainties related to the B-meson distribution amplitude and to logarithmically enhanced alpha_s corrections cancel.Comment: 27 pages, 19 figures, minor corrections, matches journal versio

Quantification of exhaled propofol is not feasible during single-lung ventilation using double-lumen tubes : A multicenter prospective observational trial

Background: Volatile propofol can be measured in exhaled air and correlates to plasma concentrations with a time delay. However, the effect of single-lung ventilation on exhaled propofol is unclear. Therefore, our goal was to evaluate exhaled propofol concentrations during single-lung compared to double-lung ventilation using double-lumen tubes. Methods: In a first step, we quantified adhesion of volatile propofol to the inner surface of double-lumen tubes during double- and single-lumen ventilation in vitro. In a second step, we enrolled 30 patients scheduled for lung surgery in two study centers. Anesthesia was provided with propofol and remifentanil. We utilized left-sided double-lumen tubes to separately ventilate each lung. Exhaled propofol concentrations were measured at 1-min intervals and plasma for propofol analyses was sampled every 20 min. To eliminate the influence of dosing on volatile propofol concentration, exhalation rate was normalized to plasma concentration. Results: In-vitro ventilation of double-lumen tubes resulted in increasing propofol concentrations at the distal end of the tube over time. In vitro clamping the bronchial lumen led to an even more pronounced increase (Δ AUC +62%) in propofol gas concentration over time. Normalized propofol exhalation during lung surgery was 31% higher during single-lung compared to double-lung ventilation. Conclusion: During single-lung ventilation, propofol concentration in exhaled air, in contrast to our expectations, increased by approximately one third. However, this observation might not be affected by change in perfusion-ventilation during singlelung ventilation but rather arises from reduced propofol absorption on the inner surface area of the double-lumen tube. Thus, it is only possible to utilize exhaled propofol concentration to a limited extent during single-lung ventilation. Registration of Clinical Trial: DRKS-ID DRKS00014788 (www.drks.de)