Gluon-induced W-boson pair production at the LHC

Pair production of W bosons constitutes an important background to Higgs boson and new physics searches at the Large Hadron Collider LHC. We have calculated the loop-induced gluon-fusion process gg -> W*W* -> leptons, including intermediate light and heavy quarks and allowing for arbitrary invariant masses of the W bosons. While formally of next-to-next-to-leading order, the gg -> W*W* -> leptons process is enhanced by the large gluon flux at the LHC and by experimental Higgs search cuts, and increases the next-to-leading order WW background estimate for Higgs searches by about 30%. We have extended our previous calculation to include the contribution from the intermediate top-bottom massive quark loop and the Higgs signal process. We provide updated results for cross sections and differential distributions and study the interference between the different gluon scattering contributions. We describe important analytical and numerical aspects of our calculation and present the public GG2WW event generator.Comment: 20 pages, 4 figure

Quality Control of Nitrogen Multiple Breath Washout in a Multicenter Pediatric Asthma Study.

BACKGROUND Nitrogen multiple breath washout (N2MBW) is a lung function test increasingly used in small airway diseases. Quality criteria have not yet been globally implemented and time-consuming retrospective overreading is necessary. Little data has been published on children with recurrent wheeze or asthma from multicentered studies. METHODS Children with wheeze or asthma and healthy controls were included in the longitudinal All Age Asthma Cohort (ALLIANCE). To assess ventilation inhomogeneity, N2MBW tests were performed in five centers from 2013 until 2020. All N2MBW tests were centrally overread by one center. Multiple washout procedures (trials) at the visit concluded to one test occasion. Tests were accepted if trials were technically sound (started correctly, terminated correctly, no leak, regular breathing pattern) and repeatable within one test occasion. Signal misalignment was retrospectively corrected. Factors that may impact test quality were analyzed, such as experience level. RESULTS N2MBW tests of n=561 participants were analyzed leading to n=949 (68.3%) valid tests of n=1,390 in total. Inter-center test acceptability ranged from 27.6% to 77.8%. End-of-test criterion and leak were identified to be the most common reasons for rejection. Data loss and uncorrectable signal misalignment led to rejection of 58% of trials in one center. In preschool children, significant improvement of test acceptability was found longitudinally (χ2(8)=18.6; p=0.02). CONCLUSION N2MBW is feasible in a multicenter asthma study in children. However, the quality of this time-consuming procedure is dependent on experience level of staff in preschool children and still requires retrospective overreading for all age groups

Validation of the Asthma Severity Scoring System (ASSESS) in the ALLIANCE cohort.

BACKGROUND The Asthma Severity Scoring System (ASSESS) quantifies asthma severity in adolescents and adults. Scale performance in children < 12 years is unknown. OBJECTIVE To validate the ASSESS score in the All Age Asthma Cohort (ALLIANCE) and explore its use in children <12 years. METHODS Scale properties, responsiveness, and known-group validity were assessed in 247 children (median age 11 years, IQR: 8-13 years) and 206 adults (median age 52 years, IQR: 43-63 years). RESULTS Overall, measures of internal test consistency and test-retest reliability were similar to the original data of the Severe Asthma Research Program (SARP). Cronbach's α was 0.59 in children 12-18 years and 0.73 in adults, reflecting the inclusion of multiple and not always congruent dimensions to the ASSESS score especially in children. Analysis of known-group validity confirmed the discriminatory power, as the ASSESS score was significantly worse in patients with poor asthma control, exacerbations and increased salbutamol use. In children between 6-11 years test reliability was inferior compared to adults and adolescents (Cronbach's α 0.27) mostly due to a less lung function impairment in asthmatic children of this age group. Known-group validity however confirmed good discriminative power regarding severity-associated variables similar to adolescents and adults. CONCLUSION Test reliability and validity of the ASSESS score was confirmed in the ALLIANCE cohort. In children aged 6-11 years internal consistency was inferior compared to older asthma patients, however test validity was good and encourages age-spanning usage of the ASSESS score in all asthma patients ≥ 6 years