Motivation

Abstract

For tests of the Standard Model and measurements of its parameters, precise predictions of the processes at the LHC are needed. To obtain a high level of accuracy for these predictions, a very good understanding of the structure of the proton is essential. In this context, the knowledge of the parton distribution functions of the proton plays a key role. For example, the PDF uncertainties can be one of the largest uncertainties on the predictions of the Higgs production cross sections Andersen et al (Handbook of LHC higgs cross sections: 3. Higgs properties, 2013). It was already seen in the analysis discussed in the previous chapters that at very high transverse masses the PDF uncertainties are the dominating theoretical uncertainties. This is also true for searches for new heavy neutral gauge bosons (commonly called $Z'$). These uncertainties are due to the not well constrained high-x region in the PDFs. The measurement of the high-mass Drell–Yan cross section gives access to the high-x quark and antiquark information. Measuring at high invariant masses and high dilepton rapidities $y_{\ell \ell }$ gives access to even higher values of x, as discussed in Sect. 2.2.3 and visible in Fig. 2.8. The measurement of this process at high invariant mass can furthermore be sensitive to electroweak corrections which have not yet been constrained Boughezal (Disentangling radiative corrections using the high-mass Drell–Yan process at the LHC. Phys Rev D89.3:034030, 2014).