Ks0andΛproduction inppinteractions at

Abstract

The production of K 0 S and à hadrons is studied in pp collision data at ffiffi ffi s p ¼ 0:9 and 7 TeV collected with the ATLAS detector at the LHC using a minimum-bias trigger. The observed distributions of transverse momentum, rapidity, and multiplicity are corrected to hadron level in a model-independent way within well-defined phase-space regions. The distribution of the production ratio of " à to à baryons is also measured. The results are compared with various Monte Carlo simulation models. Although most of these models agree with data to within 15% in the K 0 S distributions, substantial disagreements are found in the à distributions of transverse momentum.

Updating and optimizing error parton distribution function sets in the Hessian approach. II.

“…To check this, we use ePump to add each Drell-Yan data set individually to CT14HERA2mY, and compare with CT14mYeAll, which we have already shown is very close to CT14HERA2. We find that although most data sets give a similar trend, only the CMS 7 TeV µ asymmetry data [14], the CMS 7 TeV electron asymmetry data [15], the ATLAS 7 TeV W Z data [6] and the DØ Run2 µ asymmetry data [16] have an appreciable impact. This result is as expected, since most of them are lepton charge asymmetry data.…”

“…We find that while the tt data can provide potential constraints on the g-PDF, its impact is quite minimal after we have included the inclusive high transverse momentum (p T ) jet production data from the Tevatron and the LHC in the same fit. On the other hand, we find a large impact on the quark PDFs, particularly in the small-x region, when updated by adding the ATLAS 7 TeV W and Z data [6]. This large deviation of the updated PDFs from the original CT14HERA2 PDFs suggests that the ePump result should only be trusted qualitatively in this case, and for quantitative results with this data set a full global fit is required.…”

“…After observing the constraints of new LHC jet data [1] and tt data on the g-PDFs, we would also like to see how new LHC Drell-Yan data could modify the quark PDFs. The low luminosity (35 pb −1 ) ATLAS 7 TeV W ± and Z cross section data [6] were included in the CT14HERA2 fit. Since then, ATLAS has published the more precise ATLAS 7 TeV W Z data with an integrated luminosity of 4.6 fb −1 [42].…”

“…First, we examine the impact from the LHC top quark pair (tt) production data provided by ATLAS and CMS Collaborations. Second, we examine the impact from the ATLAS 7 TeV data on W and Z productions [6]. We find that while the tt data can provide potential constraints on the g-PDF, its impact is quite minimal after we have included the inclusive high transverse momentum (p T ) jet production data from the Tevatron and the LHC in the same fit.…”

An update of the ABM16 PDF fit

“…An important component of the present update are recent high-statistics Drell-Yan data collected at the LHC. In particular, the ATLAS collaboration greatly improved the accuracy of their 7 TeV W -and Z-boson sample [2], which now supersedes the earlier data set released in 2011 [3]. Besides, the data of Ref.…”