Cargando…
Measurement of Lamba(b) polarization and angular parameters in Lambda(b) to Jpsi Lambda decays from pp collisions at sqrt(s) = 7 and 8 TeV
The c and b quarks have masses significantly above of the $\Lambda_{\text{QCD}}$ QCD scale, and therefore their production and treatment should be perturbatively calculable. There are many common implementations taking these ideas, the most common QCD factorization (QCDF), perturbative QCD (pQCD), h...
Autor principal: | |
---|---|
Lenguaje: | eng |
Publicado: |
2018
|
Materias: | |
Acceso en línea: | http://cds.cern.ch/record/2648543 |
Sumario: | The c and b quarks have masses significantly above of the $\Lambda_{\text{QCD}}$ QCD scale, and therefore their production and treatment should be perturbatively calculable. There are many common implementations taking these ideas, the most common QCD factorization (QCDF), perturbative QCD (pQCD), heavy-quark-effective theory (HQET). The assumption heavy quarks remain quark information rather hadronization has support under the heavy quark approach. In this work, an analysis of the bottom baryon decay $\Lambda_\text{b}\to J/\psi\Lambda$ is performed to measure the $\Lambda_\text{b}$ polarization and three angular parameters in data from pp collisions at $\sqrt{s} = 7$ and 8\TeV, collected by the CMS experiment at the LHC. The $\Lambda_\text{b}$ polarization is measured to be $0.00 \pm 0.06$ (stat) $\pm 0.06$ (syst) and the parity-violating asymmetry parameter is determined to be $0.14 \pm 0.14$ (stat) $\pm 0.10$ (syst). The measurements are compared to various theoretical predictions, including those from perturbative quantum chromodynamics. |
---|