Speaker
Arnd Meyer
(Rheinisch-Westfaelische Tech. Hoch. (DE))
Description
Several measurements of QCD jets are presented as performed at different center-of-mass energies with the CMS experiment. By extending the measurement into the forward phase space and also towards low-pT the sensitivity to new features of QCD is maximised. The simultaneous observation of several jets in the same event is exploited to study for example the angular correlations of Mueller Navelet jet topologies in order to search for the signature of BFKL parton dynamics. Multi-jet measurements are also used to test higher-order QCD effects, and by lowering the jet pt to the smallest possible values the minijet production close to the factorization limit is studied.
Also studied is the differential diffractive cross section measured as a function of the mass of one of the two final-state hadronic systems separated by the largest rapidity gap in the event. The cross section is measured as a function of the width of the central rapidity gap, as well as for events with a forward gap over 8.4 units of pseudorapidity. The total SD and DD cross sections are extracted. Furthermore, the observation of a hard color-singlet exchange process in events with a large rapidity gap between two leading jets is reported. Moreover, also measurement of the exclusive production of pi+pi- final states and differential pi+ pi- cross sections are measured as a function of invariant mass, pT, and y. Finally, a measurement of exclusive Y production in ultra-peripheral pPb collisions is reported.
Author
Arnd Meyer
(Rheinisch-Westfaelische Tech. Hoch. (DE))
