Elliptic flow
Relativistic heavy-ion collisions produce very large numbers of subatomic particles in all directions. In such collisions, flow refers to how energy, momentum, and number of these particles varies with direction,[1] and elliptic flow is a measure of how the flow is not uniform in all directions when viewed along the beam-line. Elliptic flow is strong evidence for the existence of quark–gluon plasma, and has been described as one of the most important observations measured at the Relativistic Heavy Ion Collider (RHIC).[2][3]
Elliptic flow describes the azimuthal momentum space anisotropy of particle emission from non-central heavy-ion collisions in the plane transverse to the beam direction, and is defined as the second harmonic coefficient of the azimuthal Fourier decomposition of the momentum distribution.[4] Elliptic flow is a fundamental observable since it directly reflects the initial spatial anisotropy, of the nuclear overlap region in the transverse plane, directly translated into the observed momentum distribution of identified particles. Since the spatial anisotropy is largest at the beginning of the evolution, elliptic flow is especially sensitive to the early stages of system evolution.[5] A measurement of elliptic flow thus provides access to the fundamental thermalization time scale and many more things in the early stages of a relativistic heavy-ion collision.[4]
Notes
Page Template:Reflist/styles.css has no content.
- ^ Page Module:Citation/CS1/styles.css has no content.Reisdorf, W.; Ritter, H. G. (1997). "Collective Flow in Heavy-Ion Collisions". Annual Review of Nuclear and Particle Science. 47: 663–709. Bibcode:1997ARNPS..47..663R. doi:10.1146/annurev.nucl.47.1.663.
- ^ Page Module:Citation/CS1/styles.css has no content.Ollitrault, J. Y. (1992). "Anisotropy as a signature of transverse collective flow". Physical Review D. 46 (1): 229–245. Bibcode:1992PhRvD..46..229O. doi:10.1103/PhysRevD.46.229. PMID 10014754.
- ^ Page Module:Citation/CS1/styles.css has no content.Voloshin, S.; Zhang, Y. (1996). "Flow study in relativistic nuclear collisions by Fourier expansion of azimuthal particle distributions". Zeitschrift für Physik C. 70 (4): 665–672. arXiv:hep-ph/9407282. doi:10.1007/s002880050141. S2CID 118925144.
- ^ a b Page Module:Citation/CS1/styles.css has no content.Snellings, R. (2011). "Elliptic flow: A brief review". New Journal of Physics. 13 (5) 055008. arXiv:1102.3010. Bibcode:2011NJPh...13e5008S. doi:10.1088/1367-2630/13/5/055008. S2CID 119254339.
- ^ Page Module:Citation/CS1/styles.css has no content.Ackermann, K.; Adams, N.; Adler, C.; Ahammed, Z.; Ahmad, S.; Allgower, C.; Amsbaugh, J.; Anderson, M.; Anderssen, E.; Arnesen, H.; Arnold, L.; Averichev, G.; Baldwin, A.; Balewski, J.; Barannikova, O.; Barnby, L.; Baudot, J.; Beddo, M.; Bekele, S.; Belaga, V.; Bellwied, R.; Bennett, S.; Bercovitz, J.; Berger, J.; Betts, W.; Bichsel, H.; Bieser, F.; Bland, L.; Bloomer, M.; et al. (2001). "Elliptic Flow in Au+Au Collisions at √sNN=130 GeV". Physical Review Letters. 86 (3): 402–407. arXiv:nucl-ex/0009011. Bibcode:2001PhRvL..86..402A. doi:10.1103/PhysRevLett.86.402. PMID 11177841.
References
- Page Module:Citation/CS1/styles.css has no content."ALICE gets with the flow". CERN Courier. 30 March 2011.
- Page Module:Citation/CS1/styles.css has no content.Cramer, John G. "Solving the RHIC Puzzle". Analog Science Fiction and Fact. Archived from the original on 26 January 2012. Retrieved 11 March 2012.
