Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV

J. Adam; D. Adamova; M.M. Aggarwal; G. Aglieri Rinella; Maria Agnello; N. Agrawal; Z. Ahammed; S. U. Ahn; I. Aimo; S. Aiola; A. Akindinov; Alessandro D; Ian Bearden; Hans Bøggild; Christian Holm Christensen; Kristjan Herlache Gulbrandsen; Jens Jørgen Gaardhøje; Hans Hjersing Dalsgaard; Børge Svane Nielsen; Alexander Colliander Hansen; Ante Bilandzic; Marek Chojnacki; Valentina Zaccolo; You Zhou; Christian Alexander Bourjau

doi:10.1103/PhysRevC.93.024905

Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV

J. Adam, D. Adamova, M.M. Aggarwal, G. Aglieri Rinella, Maria Agnello, N. Agrawal, Z. Ahammed, S. U. Ahn, I. Aimo, S. Aiola, A. Akindinov, Alessandro D , Ian Bearden, Hans Bøggild, Christian Holm Christensen, Kristjan Herlache Gulbrandsen, Jens Jørgen Gaardhøje, Hans Hjersing Dalsgaard, Børge Svane Nielsen, Alexander Colliander HansenAnte Bilandzic, Marek Chojnacki, Valentina Zaccolo, You Zhou, Christian Alexander Bourjau

Experimental Particle Physics

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Abstract

We report on the measurement of freeze-out radii for pairs of identical-charge pions measured in Pb-Pb collisions at sNN=2.76 TeV as a function of collision centrality and the average transverse momentum of the pair kT. Three-dimensional sizes of the system (femtoscopic radii), as well as direction-averaged one-dimensional radii are extracted. The radii decrease with kT, following a power-law behavior. This is qualitatively consistent with expectations from a collectively expanding system, produced in hydrodynamic calculations. The radii also scale linearly with (dNch/dη)1/3. This behavior is compared to world data on femtoscopic radii in heavy-ion collisions. While the dependence is qualitatively similar to results at smaller sNN, a decrease in the ratio Rout/Rside is seen, which is in qualitative agreement with a specific prediction from hydrodynamic models: a change from inside-out to outside-in freeze-out configuration. The results provide further evidence for the production of a collective, strongly coupled system in heavy-ion collisions at the CERN Large Hadron Collider.

Original language	English
Article number	024905
Journal	Physical Review C
Volume	93
Issue number	2
ISSN	2469-9985
DOIs	https://doi.org/10.1103/PhysRevC.93.024905
Publication status	Published - 4 Feb 2016

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Adam, J., Adamova, D., Aggarwal, M. M., Aglieri Rinella, G., Agnello, M., Agrawal, N., Ahammed, Z., U. Ahn, S., Aimo, I., Aiola, S., Akindinov, A., D , A., Bearden, I., Bøggild, H., Christensen, C. H., Gulbrandsen, K. H., Gaardhøje, J. J., Dalsgaard, H. H., Nielsen, B. S., ... Bourjau, C. A. (2016). Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV. Physical Review C, 93(2), [024905]. https://doi.org/10.1103/PhysRevC.93.024905

Adam, J, Adamova, D, Aggarwal, MM, Aglieri Rinella, G, Agnello, M, Agrawal, N, Ahammed, Z, U. Ahn, S, Aimo, I, Aiola, S, Akindinov, A, D , A, Bearden, I , Bøggild, H , Christensen, CH , Gulbrandsen, KH , Gaardhøje, JJ, Dalsgaard, HH, Nielsen, BS, Hansen, AC, Bilandzic, A, Chojnacki, M, Zaccolo, V, Zhou, Y & Bourjau, CA 2016, 'Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV', Physical Review C, vol. 93, no. 2, 024905. https://doi.org/10.1103/PhysRevC.93.024905

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title = "Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV",

abstract = "We report on the measurement of freeze-out radii for pairs of identical-charge pions measured in Pb-Pb collisions at sNN=2.76 TeV as a function of collision centrality and the average transverse momentum of the pair kT. Three-dimensional sizes of the system (femtoscopic radii), as well as direction-averaged one-dimensional radii are extracted. The radii decrease with kT, following a power-law behavior. This is qualitatively consistent with expectations from a collectively expanding system, produced in hydrodynamic calculations. The radii also scale linearly with (dNch/dη)1/3. This behavior is compared to world data on femtoscopic radii in heavy-ion collisions. While the dependence is qualitatively similar to results at smaller sNN, a decrease in the ratio Rout/Rside is seen, which is in qualitative agreement with a specific prediction from hydrodynamic models: a change from inside-out to outside-in freeze-out configuration. The results provide further evidence for the production of a collective, strongly coupled system in heavy-ion collisions at the CERN Large Hadron Collider.",

author = "J. Adam and D. Adamova and M.M. Aggarwal and {Aglieri Rinella}, G. and Maria Agnello and N. Agrawal and Z. Ahammed and {U. Ahn}, S. and I. Aimo and S. Aiola and A. Akindinov and Alessandro D and Ian Bearden and Hans B{\o}ggild and Christensen, {Christian Holm} and Gulbrandsen, {Kristjan Herlache} and Gaardh{\o}je, {Jens J{\o}rgen} and Dalsgaard, {Hans Hjersing} and Nielsen, {B{\o}rge Svane} and Hansen, {Alexander Colliander} and Ante Bilandzic and Marek Chojnacki and Valentina Zaccolo and You Zhou and Bourjau, {Christian Alexander}",

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T1 - Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV

AU - Adam, J.

AU - Adamova, D.

AU - Aggarwal, M.M.

AU - Aglieri Rinella, G.

AU - Agnello, Maria

AU - Agrawal, N.

AU - Ahammed, Z.

AU - U. Ahn, S.

AU - Aimo, I.

AU - Aiola, S.

AU - Akindinov, A.

AU - D , Alessandro

AU - Bearden, Ian

AU - Bøggild, Hans

AU - Christensen, Christian Holm

AU - Gulbrandsen, Kristjan Herlache

AU - Gaardhøje, Jens Jørgen

AU - Dalsgaard, Hans Hjersing

AU - Nielsen, Børge Svane

AU - Hansen, Alexander Colliander

AU - Bilandzic, Ante

AU - Chojnacki, Marek

AU - Zaccolo, Valentina

AU - Zhou, You

AU - Bourjau, Christian Alexander

PY - 2016/2/4

Y1 - 2016/2/4

N2 - We report on the measurement of freeze-out radii for pairs of identical-charge pions measured in Pb-Pb collisions at sNN=2.76 TeV as a function of collision centrality and the average transverse momentum of the pair kT. Three-dimensional sizes of the system (femtoscopic radii), as well as direction-averaged one-dimensional radii are extracted. The radii decrease with kT, following a power-law behavior. This is qualitatively consistent with expectations from a collectively expanding system, produced in hydrodynamic calculations. The radii also scale linearly with (dNch/dη)1/3. This behavior is compared to world data on femtoscopic radii in heavy-ion collisions. While the dependence is qualitatively similar to results at smaller sNN, a decrease in the ratio Rout/Rside is seen, which is in qualitative agreement with a specific prediction from hydrodynamic models: a change from inside-out to outside-in freeze-out configuration. The results provide further evidence for the production of a collective, strongly coupled system in heavy-ion collisions at the CERN Large Hadron Collider.

AB - We report on the measurement of freeze-out radii for pairs of identical-charge pions measured in Pb-Pb collisions at sNN=2.76 TeV as a function of collision centrality and the average transverse momentum of the pair kT. Three-dimensional sizes of the system (femtoscopic radii), as well as direction-averaged one-dimensional radii are extracted. The radii decrease with kT, following a power-law behavior. This is qualitatively consistent with expectations from a collectively expanding system, produced in hydrodynamic calculations. The radii also scale linearly with (dNch/dη)1/3. This behavior is compared to world data on femtoscopic radii in heavy-ion collisions. While the dependence is qualitatively similar to results at smaller sNN, a decrease in the ratio Rout/Rside is seen, which is in qualitative agreement with a specific prediction from hydrodynamic models: a change from inside-out to outside-in freeze-out configuration. The results provide further evidence for the production of a collective, strongly coupled system in heavy-ion collisions at the CERN Large Hadron Collider.

U2 - 10.1103/PhysRevC.93.024905

DO - 10.1103/PhysRevC.93.024905

M3 - Journal article

SN - 2469-9985

VL - 93

JO - Physical Review C

JF - Physical Review C

IS - 2

M1 - 024905

ER -

Centrality dependence of pion freeze-out radii in Pb-Pb collisions at root s(NN)=2.76 TeV

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