TY - JOUR AU - Knutsson, A. TI - Multiple interactions at HERA JO - Nuclear physics / B / Proceedings supplements VL - 191 SN - 0920-5632 CY - Amsterdam PB - Elsevier M1 - PUBDB-2015-04361 SP - 141 - 150 PY - 2009 N1 - © Elsevier B.V. AB - Presented are recent measurements in ep collisions at HERA, which comprise results that are expected to be sensitive to multiple interactions and the underlying event. A measurement of 3- and 4-jet event cross-sections in photoproduction, as well as two measurements which target the activity in the soft underlying event in photoproduction and deep inelastic scattering at low photon virtuality (Q^2), respectively, are reviewed. The data are compared to various QCD models with and without multiple i nteractions simulated. The multijet event cross-sections are in addition compared to a fixed-order O(@a@a_s^2) calculation. T2 - Ringberg Workshop on New Trends in HERA Physics 2008 CY - 5 Oct 2008 - 10 Oct 2008, Ringberg Castle (Germany) Y2 - 5 Oct 2008 - 10 Oct 2008 M2 - Ringberg Castle, Germany LB - PUB:(DE-HGF)16 UR - <Go to ISI:>//WOS:000267433400015 DO - DOI:10.1016/j.nuclphysbps.2009.03.121 UR - https://bib-pubdb1.desy.de/record/276003 ER -