Speaker
Colin Barschel
(CERN)
Description
Measuring cross-sections at the LHC requires the luminosity to be
determined accurately at each centre-of-mass energy $\sqrt{s}$.
The ALICE, ATLAS, CMS and LHCb experiments use the Van der Meer (VDM)
method to determine the luminosity. In addition, LHCb uses a novel
method based on beam-gas imaging (BGI) to perform a complementary
calibration.
Considerable effort has been invested at the LHC in the past
few years to understand systematic limitations and improve the
precision of such calibrations down to the level of 1-2%.
Transverse beam shape non-factorizability has been found to be one
of the limiting factors, along with the length scale calibration,
beam stability and fit models.
Here, an overview of the most recent findings on luminosity calibration
from the ALICE, ATLAS, CMS and LHCb experiments in p-p collisions
($\sqrt{s}$ = 13 and 5 TeV) and Pb-Pb collisions (5 TeV) is presented.
Author
Colin Barschel
(CERN)
