Measurement of event background fluctuations for charged particle jet reconstruction in Pb-Pb collisions at √s= 2.76 TeV
Articolo
Data di Pubblicazione:
2012
Abstract:
The effect of event background fluctuations on charged particle jet reconstruction in Pb-Pb collisions at √sNN = 2:76TeV has been measured with the ALICE experiment.
The main sources of non-statistical fluctuations are characterized based purely onexperimental data with an unbiased method, as well as by using single high pt particles and simulated jets embedded into real Pb-Pb events and reconstructed with the anti-kt jet finder. The influence of a low transverse momentum cut-off on particles used in the
jet reconstruction is quantified by varying the minimum track pt between 0.15 GeV/c and 2 GeV/c. For embedded jets reconstructed from charged particles with pt > 0.15 GeV/c,
the uncertainty in the reconstructed jet transverse momentum due to the heavy-ion background is measured to be 11.3 GeV/c (standard deviation) for the 10% most central Pb-Pb collisions, slightly larger than the value of 11.0 GeV/c measured using the unbiased method. For a higher particle transverse momentum threshold of 2 GeV/c, which will generate a stronger bias towards hard fragmentation in the jet nding process, the standard deviation of the fluctuations in the reconstructed jet transverse momentum is reduced to
4.8-5.0 GeV/c for the 10% most central events. A non-Gaussian tail of the momentum uncertainty is observed and its impact on the reconstructed jet spectrum is evaluated for
varying particle momentum thresholds, by folding the measured fluctuations with steeply falling spectra.
The main sources of non-statistical fluctuations are characterized based purely onexperimental data with an unbiased method, as well as by using single high pt particles and simulated jets embedded into real Pb-Pb events and reconstructed with the anti-kt jet finder. The influence of a low transverse momentum cut-off on particles used in the
jet reconstruction is quantified by varying the minimum track pt between 0.15 GeV/c and 2 GeV/c. For embedded jets reconstructed from charged particles with pt > 0.15 GeV/c,
the uncertainty in the reconstructed jet transverse momentum due to the heavy-ion background is measured to be 11.3 GeV/c (standard deviation) for the 10% most central Pb-Pb collisions, slightly larger than the value of 11.0 GeV/c measured using the unbiased method. For a higher particle transverse momentum threshold of 2 GeV/c, which will generate a stronger bias towards hard fragmentation in the jet nding process, the standard deviation of the fluctuations in the reconstructed jet transverse momentum is reduced to
4.8-5.0 GeV/c for the 10% most central events. A non-Gaussian tail of the momentum uncertainty is observed and its impact on the reconstructed jet spectrum is evaluated for
varying particle momentum thresholds, by folding the measured fluctuations with steeply falling spectra.
Tipologia CRIS:
1.1 Articolo in rivista
Keywords:
Heavy ions
Elenco autori:
Abelev, B.; Adam, J.; Adamová, D.; Adare, A. M.; Aggarwal, M. M.; Aglieri Rinella, G.; Agocs, A. G.; Agostinelli, A.; Aguilar Salazar, S.; Ahammed, Z.; Ahmad, N.; Ahmad Masoodi, A.; Ahn, S. U.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alfaro Molina, R.; Alici, A.; Alkin, A.; Almaráz Aviña, E.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Anson, C.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Äystö, J.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bailhache, R.; Bala, R.; Baldini Ferroli, R.; Baldisseri, A.; Baldit, A.; Baltasar Dos Santos Pedrosa, F.; Bán, J.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Bathen, B.; Batigne, G.; Batyunya, B.; Baumann, C.; Bearden, I. G.; Beck, H.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bergmann, C.; Berzano, D.; Betev, L.; Bhasin, A.; Bhati, A. K.; Bianchi, N.; Bianchi, L.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Bock, N.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bose, S.; Bossú, F.; Botje, M.; Böttger, S.; Boyer, B.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Bugaiev, K.; Busch, O.; Buthelezi, Z.; Caballero Orduna, D.; Caffarri, D.; Cai, X.; Caines, H.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carlin Filho, N.; Carminati, F.; Carrillo Montoya, C. A.; Casanova Díaz, A.; Caselle, M.; Castillo Castellanos, J.; Castillo Hernandez, J. F.; Casula, E. A. R.; Catanescu, V.; Cavicchioli, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chiavassa, E.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Coccetti, F.; Coffin, J. -P.; Colamaria, F.; Colella, D.; Conesa Balbastre, G.; Conesa del Valle, Z.; Constantin, P.; Contin, G.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Cotallo, M. E.; Crescio, E.; Crochet, P.; Cruz Alaniz, E.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dalsgaard, H. H.; Danu, A.; Das, K.; Das, D.; Das, I.; Dash, A.; Dash, S.; De, S.; Azevedo Moregula, A.; Barros, G. O. V.; Caro, A.; Cataldo, G.; Cuveland, J.; Falco, A.; Gruttola, D.; Delagrange, H.; Castillo Sanchez, E.; Deloff, A.; Demanov, V.; Marco, N.; Dénes, E.; Pasquale, S.; Deppman, A.; Erasmo, G. D.; Rooij, R.; Bari, D.; Dietel, T.; Giglio, C.; Liberto, S.; Mauro, A.; Nezza, P.; Divià, R.; Djuvsland, Ø.; Dobrin, A.; Dobrowolski, T.; Domínguez, I.; Dönigus, B.; Dordic, O.; Driga, O.; Dubey, A. K.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Dutta Majumdar, M. R.; Elia, D.; Emschermann, D.; Engel, H.; Erdal, H. A.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Eyyubova, G.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fearick, R.; Fedunov, A.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feofilov, G.; Fernández Téllez, A.; Ferretti, A.; Ferretti, R.; Figiel, J.; Figueredo, M. A. S.; Filchagin, S.; Fini, R.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Fragkiadakis, M.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A.; Gallio, M.;
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