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Zhang, F.

Publications and source records attributed to Zhang, F..

At least 109 records · Page 6
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DOE OSTI2017

Procedures for cryogenic X-ray ptychographic imaging of biological samples

Biological sample-preparation procedures have been developed for imaging human chromosomes under cryogenic conditions. A new experimental setup, developed for imaging frozen samples using beamline I13 at Diamond Light Source, is described. This manuscript describes the equipment and experimental procedures as well as the authors' first ptychographic reconstructions using X-rays.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

Measurement of the $t\bar{t}$ production cross section in lepton+jets final states in pp collisions at 8 TeV and ratio of 8 to 7 TeV cross sections

A measurement of the top quark pair production ($t\bar{t}$) cross section in proton-proton collisions at the centre-of-mass energy of 8 TeV is presented using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.6 fb$^{-1}$. This analysis is performed in the $t\bar{t}$ decay channels with one isolated, high transverse momentum electron or muon and at least four jets, at least one of which is required to be identified as originating from hadronization of a b quark. The calibration of the jet energy scale and the efficiency of b~jet identification are determined from data. The measured $\mathrm{ t \bar{t} }$ cross section is 228.5 $\pm$ 3.8 (stat) $\pm$ 13.7 (syst) $\pm$ 6.0 (lumi) pb. This measurement is compared with an analysis of 7 TeV data, corresponding to an integrated luminosity of 5.0 fb$^{-1}$, to determine the ratio of 8 TeV to 7 TeV cross sections, which is found to be 1.43 $\pm$ 0.04 (stat) $\pm$ 0.07 (syst) $\pm$ 0.05 (lumi). Finally, the measurements are in agreement with QCD predictions up to next-to-next-to-leading order.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗