Jie Zhang

Bio: Jie Zhang is an academic researcher from East China University of Science and Technology. The author has contributed to research in topics: Medicine & Large Hadron Collider. The author has an hindex of 178, co-authored 4857 publications receiving 221720 citations. Previous affiliations of Jie Zhang include University of Bedfordshire & CERN.

Measurements of tt¯ differential cross-sections of highly boosted top quarks decaying to all-hadronic final states in pp collisions at √s =13 TeV using the ATLAS detector

Abstract: Measurements are made of differential cross-sections of highly boosted pair-produced top quarks as a function of top-quark and t (t) over bar system kinematic observables using proton-proton collis ...

Measurements of differential Z boson production cross sections in proton-proton collisions at s√ = 13 TeV

Abstract: Measurements are presented of the differential cross sections for Z bosons produced in proton-proton collisions at $$ \sqrt{s} $$ = 13 TeV and decaying to muons and electrons. The data analyzed were collected in 2016 with the CMS detector at the LHC and correspond to an integrated luminosity of 35.9 fb−1. The measured fiducial inclusive product of cross section and branching fraction agrees with next-to-next-to-leading order quantum chromodynamics calculations. Differential cross sections of the transverse momentum pT, the optimized angular variable $$ {\phi}_{\eta}^{\ast } $$ , and the rapidity of lepton pairs are measured. The data are corrected for detector effects and compared to theoretical predictions using fixed order, resummed, and parton shower calculations. The uncertainties of the measured normalized cross sections are smaller than 0.5% for $$ {\phi}_{\eta}^{\ast } $$ < 0.5 and for $$ {p}_{\mathrm{T}}^{\mathrm{Z}} $$ < 50 GeV.

Experimental constraints on the possible J**P quantum numbers of the Lambda(c)(2880)+

Abstract: We report the results of several studies of the {lambda}{sub c}{sup +}{pi}{sup +}{pi}{sup -}X final state in continuum e{sup +}e{sup -} annihilation data collected by the Belle detector. An analysis of angular distributions in {lambda}{sub c}(2880){sup +}{yields}{sigma}{sub c}(2455){sup 0,++}{pi}{sup +,-} decays strongly favors a {lambda}{sub c}(2880){sup +} spin assignment of (5/2) over (3/2) or (1/2). We find evidence for {lambda}{sub c}(2880){sup +}{yields}{sigma}{sub c}(2520){sup 0,++}{pi}{sup +,-} decay and measure the ratio of {lambda}{sub c}(2880){sup +} partial widths {gamma}({sigma}{sub c}(2520){pi})/{gamma}({sigma}{sub c}(2455){pi})=0.225{+-}0.062{+-}0.= 025. This value favors the {lambda}{sub c}(2880){sup +} spin-parity assignment of (5/2){sup +} over (5/2){sup -}. We also report the first observation of {lambda}{sub c}(2940){sup +}{yields}{sigma}{sub c}(2455){sup 0,++}{pi}{sup +,-} decay and measure {lambda}{sub c}(2880){sup +} and {lambda}{sub c}(2940){sup +} mass and width parameters. These studies are based on a 553 fb{sup -1} data sample collected at or near the {upsilon}(4S) resonance at the KEKB collider.

A search for flavour changing neutral currents in top-quark decays in $pp$ collision data collected with the ATLAS detector at $s=7$ TeV

Abstract: A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of root s = 7 TeV during 2011, corresponding to an integrated luminosity of 2.1 fb(-1), were used. A search was performed for top-quark pair-production events, with one top quark decaying through the t -> Zq FCNC (q = u, c) channel, and the other through the Standard Model dominant mode t -> Wb. Only the decays of the Z boson to charged leptons and leptonic W-boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated charged leptons, at least two jets and missing transverse momentum from the undetected neutrino. No evidence for an FCNC signal was found. An upper limit on the t -> Zq branching ratio of BR(t -> Zq) < 0.73% is set at the 95% confidence level.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

A new mathematical model for relative quantification in real-time RT-PCR.

Abstract: Use of the real-time polymerase chain reaction (PCR) to amplify cDNA products reverse transcribed from mRNA is on the way to becoming a routine tool in molecular biology to study low abundance gene expression. Real-time PCR is easy to perform, provides the necessary accuracy and produces reliable as well as rapid quantification results. But accurate quantification of nucleic acids requires a reproducible methodology and an adequate mathematical model for data analysis. This study enters into the particular topics of the relative quantification in real-time RT–PCR of a target gene transcript in comparison to a reference gene transcript. Therefore, a new mathematical model is presented. The relative expression ratio is calculated only from the real-time PCR efficiencies and the crossing point deviation of an unknown sample versus a control. This model needs no calibration curve. Control levels were included in the model to standardise each reaction run with respect to RNA integrity, sample loading and inter-PCR variations. High accuracy and reproducibility (<2.5% variation) were reached in LightCycler PCR using the established mathematical model.