Title First measurement of the underlying event activity at the LHC with $\sqrt{s}$ = 0.9 TeV Author Khachatryan, V. Sirunyan, A. M. Tumasyan, A. de Wolf, E.A. Janssen, X. Mucibello, L. Roland, B. Rougny, R. Selvaggi, M. van Haevermaet, H. Van Mechelen, P. Van Remortel, N. et al. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 2010 Berlin , 2010 Subject Physics Source (journal) European physical journal : C : particles and fields. - Berlin Volume/pages 70(2010) :3 , p. 555-572 ISSN 1434-6044 ISI 000285200000003 Carrier E Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract A measurement of the underlying activity in scattering processes with p T scale in the GeV region is performed in protonproton collisions at $\sqrt{s} = 0.9$ TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged particles with pseudorapidity |η|<2, p T >0.5 GeV/c, and azimuthal direction transverse to that of the leading object. E-info https://repository.uantwerpen.be/docman/iruaauth/1b7709/dbe5e6a5d62.pdf http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000285200000003&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000285200000003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000285200000003&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle