Centrality dependence of pion freeze-out radii in Pb-Pb collisions at sNN =2.76 TeV

ALICE Collaboration

doi:10.1103/PhysRevC.93.024905

Centrality dependence of pion freeze-out radii in Pb-Pb collisions at sNN =2.76 TeV

ALICE Collaboration

Research output: Contribution to journal › Article › peer-review

62 Scopus citations

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
DOIs	https://doi.org/10.1103/PhysRevC.93.024905
State	Published - Feb 4 2016
Externally published	Yes

Funding

The Ministry of Education of Slovakia; Department of Science and Technology, South Africa; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), E-Infrastructure shared between Europe and Latin America (EELA), Ministerio de Economia y Competitividad (MINECO) of Spain, Xunta de Galicia (Conselleria de Educacion), Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Cubaenergia, Cuba, and IAEA (International Atomic Energy Agency); Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW); Ukraine Ministry of Education and Science; United Kingdom Science and Technology Facilities Council (STFC); The United States Department of Energy, the United States National Science Foundation, the State of Texas, and the State of Ohio; Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund, Croatia; Council of Scientific and Industrial Research (CSIR), New Delhi, India; Pontificia Universidad Catolica del Pera.

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10.1103/PhysRevC.93.024905

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@article{8973d2ed3291474f8ec0bf6128130a0d,

title = "Centrality dependence of pion freeze-out radii in Pb-Pb collisions at sNN =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 = "{ALICE Collaboration} and J. Adam and D. Adamov{\'a} and Aggarwal, {M. M.} and {Aglieri Rinella}, G. and M. Agnello and N. Agrawal and Z. Ahammed and Ahn, {S. U.} and I. Aimo and S. Aiola and M. Ajaz and A. Akindinov and Alam, {S. N.} and D. Aleksandrov and B. Alessandro and D. Alexandre and {Alfaro Molina}, R. and A. Alici and A. Alkin and Almaraz, {J. R.M.} and J. Alme and T. Alt and S. Altinpinar and I. Altsybeev and {Alves Garcia Prado}, C. and C. Andrei and A. Andronic and V. Anguelov and J. Anielski and T. Anti{\v c}i{\'c} and F. Antinori and P. Antonioli and L. Aphecetche and H. Appelsh{\"a}user and S. Arcelli and N. Armesto and R. Arnaldi and Arsene, {I. C.} and M. Arslandok and B. Audurier and A. Augustinus and R. Averbeck and Azmi, {M. D.} and M. Bach and A. Badal{\`a} and Baek, {Y. W.} and S. Bagnasco and R. Bailhache and F. Bock and Read, {K. F.}",

note = "Publisher Copyright: {\textcopyright} 2016 CERN.",

year = "2016",

month = feb,

day = "4",

doi = "10.1103/PhysRevC.93.024905",

language = "English",

volume = "93",

journal = "Physical Review C",

issn = "2469-9985",

publisher = "American Physical Society",

number = "2",

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TY - JOUR

T1 - Centrality dependence of pion freeze-out radii in Pb-Pb collisions at sNN =2.76 TeV

AU - ALICE Collaboration

AU - Adam, J.

AU - Adamová, D.

AU - Aggarwal, M. M.

AU - Aglieri Rinella, G.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahn, S. U.

AU - Aimo, I.

AU - Aiola, S.

AU - Ajaz, M.

AU - Akindinov, A.

AU - Alam, S. N.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alexandre, D.

AU - Alfaro Molina, R.

AU - Alici, A.

AU - Alkin, A.

AU - Almaraz, J. R.M.

AU - Alme, J.

AU - Alt, T.

AU - Altinpinar, S.

AU - Altsybeev, I.

AU - Alves Garcia Prado, C.

AU - Andrei, C.

AU - Andronic, A.

AU - Anguelov, V.

AU - Anielski, J.

AU - Antičić, T.

AU - Antinori, F.

AU - Antonioli, P.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arcelli, S.

AU - Armesto, N.

AU - Arnaldi, R.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Audurier, B.

AU - Augustinus, A.

AU - Averbeck, R.

AU - Azmi, M. D.

AU - Bach, M.

AU - Badalà, A.

AU - Baek, Y. W.

AU - Bagnasco, S.

AU - Bailhache, R.

AU - Bock, F.

AU - Read, K. F.

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.

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U2 - 10.1103/PhysRevC.93.024905

DO - 10.1103/PhysRevC.93.024905

M3 - Article

AN - SCOPUS:84959387322

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 sNN =2.76 TeV

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