First proton–proton collisions at the LHC as observed with the ALICE detector: Measurement of the charged-particle pseudorapidity density at $\sqrt{s}=900$  GeV

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 on...

Full description

Saved in:
Bibliographic Details
Published in:The European physical journal. C, Particles and fields Particles and fields, 2009-12, Vol.65 (1-2)
Main Authors: Ahmad, A., Angelov, V., Anson, C., Anzo, A., Bablok, S., Baldit, A., Barbera, R., Beole, S., Bielčíková, J., Blanco, F., Bock, N., Boldizsár, L., Braun-Munzinger, P., Breitner, T., Bugaev, K., Busch, O., Chattopadhyay, S., Conesa Balbastre, G., Conesa del Valle, Z., Cosentino, M. R., de Gaspari, M., De Marco, N., Di Liberto, S., Dietel, T., Divià, R., Domínguez, I., Dutta Majumdar, A. K., Dutta Majumdar, M. R., Evans, D., Gagliardi, M., Gallio, M., Ganti, M. S., Ghidini, B., Hamar, G., Han, B. H., Hartig, M., Hori, Y., Humanic, T. J., Ivanov, M., Jančurová, L., Jusko, A., Kapitan, J., Karavicheva, T., Khan, S. A., Kim, S. H., Kox, S., Kravčáková, A., Kutouski, M., Lackner, F., Lal, C., Lazzeroni, C., Mahajan, A., Mao, Y., Martínez, M. I., Menchaca-Rocha, A., Morando, M., Munoz, J., Nielsen, B. S., Novitzky, N., Nygaard, C., Ortona, G., Oskamp, C., Oskarsson, A., Pachmayer, Y., Pagano, P., Panse, R., Peitzmann, T., Pérez, C., Pinsky, L., Płoskoń, M., Podesta Lerma, P. L. M., Poghosyan, M. G., Pommeresch, B., Pruneau, C. A., Reshetin, A., Revol, J. -P., Riedler, P., Ryabinkin, E., Sakata, D., Samsonov, V., Schmidt, C., Schweda, K., Seo, J., Sicking, E., Soos, C., Stefanini, G., Steyn, G., Symons, T. J. M., Szarka, I., Takahashi, J., Tanabe, R., Tauro, A., Traczyk, T., Turvey, A., van den Brink, A., Vannucci, L., Vechernin, V., Vinogradov, L., Windelband, B., Yushmanov, I.
Format: Article
Language:English
Subjects:
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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. In the range |η|
ISSN:1434-6044
1434-6052