First proton-proton collisions at the LHC as observed with the ALICE detector: measurement of the charged-particle pseudorapidity density at root s=900 GeV

0435890 - ÚJF 2015 RIV US eng J - Journal Article
Aamodt, K. - Adamová, Dagmar - Bielčík, J. - Bielčíková, Jana - Kapitán, Jan - Král, J. - Krus, M. - Kushpil, Svetlana - Kushpil, Vasilij - Mareš, Jiří A. - Pachr, M. - Petráček, V. - Polák, Karel - Pospíšil, V. - Šmakal, R. - Šumbera, Michal - Tlustý, D. - Wagner, V. - Závada, Petr - Zycháček, V. … Total 1055 authors
First proton-proton collisions at the LHC as observed with the ALICE detector: measurement of the charged-particle pseudorapidity density at root s=900 GeV.
European Physical Journal C. Roč. 65, 1-2 (2010), s. 111-125. ISSN 1434-6044. E-ISSN 1434-6052
R&D Projects: GA MŠMT LA09013
Institutional support: RVO:68378271 ; RVO:61389005
Keywords : ALICE * high energies * hadrons
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BF - Elementary Particles and High Energy Physics (FZU-D)
Impact factor: 3.248, year: 2010

On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in both the longitudinal and transverse directions and 284 events were recorded in coincidence with the two passing proton bunches. The events were immediately reconstructed and analyzed both online and offline. We have used these events to measure the pseudorapidity density of charged primary particles in the central region.
Permanent Link: http://hdl.handle.net/11104/0239788