Erratum to: Cottingham formula and nucleon polarisabilities

This erratum corrects some misprints appearing in the article. They do not affect any of the results

Cottingham formula and nucleon polarisabilities

The difference between the electromagnetic selfenergies of proton and neutron can be calculated with the Cottingham formula, which expresses the self-energies as an integral over the electroproduction cross sections – provided the nucleon matrix elements of the current commutator do not contain a fixed pole. We show that, under the same proviso, the subtraction function occurring in the dispersive representation of the virtual Compton forward scattering amplitude is determined by the cross sections. The representation in particular leads to a parameter-free sum rule for the nucleon polarisabilities. We evaluate the sum rule for the difference between the electric polarisabilities of proton and neutron by means of the available parameterisations of the data and compare the result with experiment

Complications of retroperitoneoscopic living donor nephrectomy: single center experience after 164 cases

Objectives: Retroperitoneoscopic living donor nephrectomy (RLDN) is used by only a few centers worldwide. Similar to laparoscopic living donor nephrectomy it offers the donor rapid convalescence and excellent cosmetic results. However, concerns have been expressed over the safety of endoscopic living donor nephrectomy. Methods: We review the results of 164 consecutive RLDN from November 2001 to November 2007. Complications were classified into intra- and early postoperative. Results: Mean donor age was 53.4±10.7years (27-79). Left kidneys were harvested in 76% of cases. Mean operation time was 146±44min (55-270), and warm ischemia time 131±45s (50-280). In two patients (1.2%) conversion to open nephrectomy was necessary. The intraoperative complication rate was 3.0%. In the postoperative period we observed in 17.7% minor complications with no persisting impairments for the donor. The rate of major complications in the early postoperative period was 4.3%. Three patients (1.8%) necessitated revision, due to laceration of the external iliac artery in one patient and chyloretroperitoneum in two patients. Mean donor creatinine was 113.1±26.6mg/dl (63-201) on the first postoperative day, and 102.0±22.2mg/dl (68-159) on the fifth postoperative day. Conclusion: Retroperitoneoscopic living donor nephrectomy can be performed with acceptable intraoperative and early postoperative morbidity. Operation times and warm ischemia times are comparable to the open approac

Retroperitoneoscopic donor nephrectomy: donor outcome and complication rate in comparison with three different techniques

Four surgical techniques for living donor nephrectomy were analyzed retrospectively in terms of perioperative outcome and early complication rate. A total of 182 donor nephrectomies including 69 open (OLDN), 14 fully laparoscopic (LDN), 34 hand-assisted laparoscopic (HLDN) and 65 retroperitoneoscopic (RLDN) nephrectomies were analyzed. There was a significant difference in mean operating time (OPT) between the OLDN (160min) and RLDN (150min) as compared to the LDN (212min) and HLDN group (192min) (P<0.001). Mean warm ischemia time (WIT) was significantly shorter with OLDN (114s), RLDN (121s) and HLDN (128s) when compared to LDN (238s) (P<0.001). Major complication rate was comparable among the groups. Independent of the preferred technique, donor nephrectomy is associated with complication rates. RLDN is comparable to OLDN in terms of OPT, WIT. Learning endoscopic donor nephrectomy could be associated with a higher complication rat

Cusps in K --> 3pi decays: a theoretical framework

Based on the analysis of 6.031*10^7 K+- --> pi0 pi0 pi+- decays, the NA48/2 collaboration has recently determined the S-wave pi-pi scattering lengths a_0-a_2 with high precision. In addition, the scattering length a_2 has been independently measured, although less precisely so. The present article discusses in detail one of the theoretical frameworks used in the data analysis.Comment: 50 pages, 20 figure

Solving integral equations in η→3π\eta\to 3\pi

A dispersive analysis of $\eta\to 3\pi$ decays has been performed in the past by many authors. The numerical analysis of the pertinent integral equations is hampered by two technical difficulties: i) The angular averages of the amplitudes need to be performed along a complicated path in the complex plane. ii) The averaged amplitudes develop singularities along the path of integration in the dispersive representation of the full amplitudes. It is a delicate affair to handle these singularities properly, and independent checks of the obtained solutions are demanding and time consuming. In the present article, we propose a solution method that avoids these difficulties. It is based on a simple deformation of the path of integration in the dispersive representation (not in the angular average). Numerical solutions are then obtained rather straightforwardly. We expect that the method also works for $\omega\to 3\pi$.Comment: 11 pages, 10 Figures. Version accepted for publication in EPJC. The ancillary files contain an updated set of fundamental solutions. The numerical differences to the former set are tiny, see the READMEv2 file for detail

Theoretical progress on cusp effect and Kl4 decays

The cusp effect in K \to 3\pi and data on K_e4 decays allow one to extract experimental information on the elastic \pi\pi scattering amplitude near threshold, and to confront the outcome of the analyses with predictions made in the framework of QCD. In my talk I pointed out that these predictions concern an isospin symmetric world, while experiments are carried out in the real world, where isospin breaking effects -- generated by electromagnetic interactions and by the mass difference of the up and down quarks -- are always present. I discussed the corrections required to account for these, so that a meaningful comparison with the predictions becomes possible. In particular, I pointed out that there is a spectacular isospin breaking effect in K_e4 decays, overlooked so far. Once it is taken into account, the previous discrepancy between NA48/2 data on K_e4 decays and the prediction of \pi\pi scattering lengths disappears