Bibcode
Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Grossmann, J.; Hrubec, J.; Jeitler, M.; König, A.; Krammer, N.; Krätschmer, I.; Liko, D.; Madlener, T.; Mikulec, I.; Pree, E.; Rabady, D.; Rad, N.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Spanring, M.; Spitzbart, D.; Strauss, J.; Waltenberger, W.; Wittmann, J.; Wulz, C.-E.; Zarucki, M.; Chekhovsky, V.; Mossolov, V.; Suarez Gonzalez, J.; De Wolf, E. A.; Janssen, X.; Lauwers, J.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; De Bruyn, I.; De Clercq, J.; Deroover, K.; Flouris, G.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Skovpen, K.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Brun, H.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Luetic, J.; Maerschalk, T.; Marinov, A.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Vannerom, D.; Yonamine, R.; Zenoni, F.; Zhang, F.; Cimmino, A.; Cornelis, T.; Dobur, D.; Fagot, A.; Gul, M.; Khvastunov, I.; Poyraz, D.; Roskas, C.; Salva, S.; Tytgat, M.; Verbeke, W.; Zaganidis, N.; Bakhshiansohi, H.; Bondu, O.; Brochet, S. et al.
Bibliographical reference
Physical Review C, Volume 96, Issue 6, id.064902
Advertised on:
12
2017
Citations
23
Refereed citations
21
Description
For the first time a principle-component analysis is used to separate
out different orthogonal modes of the two-particle correlation matrix
from heavy ion collisions. The analysis uses data from
√{sNN}=2.76 TeV PbPb and
√{sNN}=5.02 TeV p Pb collisions collected by
the CMS experiment at the CERN Large Hadron Collider. Two-particle
azimuthal correlations have been extensively used to study hydrodynamic
flow in heavy ion collisions. Recently it was shown that the expected
factorization of two-particle results into a product of the constituent
single-particle anisotropies is broken. The new information provided by
these modes may shed light on the breakdown of flow factorization in
heavy ion collisions. The first two modes ("leading" and "subleading")
of two-particle correlations are presented for elliptical and triangular
anisotropies in PbPb and p Pb collisions as a function of pT
over a wide range of event activity. The leading mode is found to be
essentially equivalent to the anisotropy harmonic previously extracted
from two-particle correlation methods. The subleading mode represents a
new experimental observable and is shown to account for a large fraction
of the factorization breaking recently observed at high transverse
momentum. The principle-component analysis technique was also applied to
multiplicity fluctuations. These also show a subleading mode. The
connection of these new results to previous studies of factorization is
discussed.