Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV

B. Abelev; J. Adam; D. Adamova; A.M. Adare; M.M. Aggarwal; Ian Bearden; Hans Bøggild; Christian Holm Christensen; Hans Hjersing Dalsgaard; Ante Bilandzic; Kristjan Herlache Gulbrandsen; Jens Jørgen Gaardhøje; Alexander Colliander Hansen; Børge Svane Nielsen; Casper Nygaard; Carsten Søgaard

doi:10.1016/j.physletb.2013.05.039

Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV

B. Abelev, J. Adam, D. Adamova, A.M. Adare, M.M. Aggarwal, Ian Bearden, Hans Bøggild, Christian Holm Christensen, Hans Hjersing Dalsgaard, Ante Bilandzic, Kristjan Herlache Gulbrandsen, Jens Jørgen Gaardhøje, Alexander Colliander Hansen, Børge Svane Nielsen, Casper Nygaard, Carsten Søgaard

Experimental Particle Physics

37 Citations (Scopus)

Abstract

In high-energy heavy-ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this Letter, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity (d?) and azimuthal angle (df) in Pb-Pb collisions at sNN=2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in df but fails to describe the correlations in d?. A thermal blast-wave model incorporating local charge conservation and tuned to describe the p_Tspectra and v₂measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze-out. The comparison of our results with measurements at lower energies reveals an ordering with sNN: the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in d? and df with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy-ion collision.

Original language	English
Journal	Physics Letters B
Volume	723
Issue number	4-5
Pages (from-to)	267-279
ISSN	0370-2693
DOIs	https://doi.org/10.1016/j.physletb.2013.05.039
Publication status	Published - 25 Jun 2013

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Abelev, B., Adam, J., Adamova, D., Adare, A. M., Aggarwal, M. M., Bearden, I., Bøggild, H., Christensen, C. H., Dalsgaard, H. H., Bilandzic, A., Gulbrandsen, K. H., Gaardhøje, J. J., Hansen, A. C., Nielsen, B. S., Nygaard, C., & Søgaard, C. (2013). Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV. Physics Letters B, 723(4-5), 267-279. https://doi.org/10.1016/j.physletb.2013.05.039

Abelev, B, Adam, J, Adamova, D, Adare, AM, Aggarwal, MM, Bearden, I , Bøggild, H , Christensen, CH, Dalsgaard, HH, Bilandzic, A, Gulbrandsen, KH , Gaardhøje, JJ, Hansen, AC, Nielsen, BS, Nygaard, C & Søgaard, C 2013, 'Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV', Physics Letters B, vol. 723, no. 4-5, pp. 267-279. https://doi.org/10.1016/j.physletb.2013.05.039

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title = "Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV",

abstract = "In high-energy heavy-ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this Letter, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity (d?) and azimuthal angle (df) in Pb-Pb collisions at sNN=2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in df but fails to describe the correlations in d?. A thermal blast-wave model incorporating local charge conservation and tuned to describe the pTspectra and v2measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze-out. The comparison of our results with measurements at lower energies reveals an ordering with sNN: the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in d? and df with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy-ion collision.",

author = "B. Abelev and J. Adam and D. Adamova and A.M. Adare and M.M. Aggarwal and Ian Bearden and Hans B{\o}ggild and Christensen, {Christian Holm} and Dalsgaard, {Hans Hjersing} and Ante Bilandzic and Gulbrandsen, {Kristjan Herlache} and Gaardh{\o}je, {Jens J{\o}rgen} and Hansen, {Alexander Colliander} and Nielsen, {B{\o}rge Svane} and Casper Nygaard and Carsten S{\o}gaard",

year = "2013",

month = jun,

day = "25",

doi = "10.1016/j.physletb.2013.05.039",

language = "English",

volume = "723",

pages = "267--279",

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TY - JOUR

T1 - Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV

AU - Abelev, B.

AU - Adam, J.

AU - Adamova, D.

AU - Adare, A.M.

AU - Aggarwal, M.M.

AU - Bearden, Ian

AU - Bøggild, Hans

AU - Christensen, Christian Holm

AU - Dalsgaard, Hans Hjersing

AU - Bilandzic, Ante

AU - Gulbrandsen, Kristjan Herlache

AU - Gaardhøje, Jens Jørgen

AU - Hansen, Alexander Colliander

AU - Nielsen, Børge Svane

AU - Nygaard, Casper

AU - Søgaard, Carsten

PY - 2013/6/25

Y1 - 2013/6/25

N2 - In high-energy heavy-ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this Letter, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity (d?) and azimuthal angle (df) in Pb-Pb collisions at sNN=2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in df but fails to describe the correlations in d?. A thermal blast-wave model incorporating local charge conservation and tuned to describe the pTspectra and v2measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze-out. The comparison of our results with measurements at lower energies reveals an ordering with sNN: the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in d? and df with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy-ion collision.

AB - In high-energy heavy-ion collisions, the correlations between the emitted particles can be used as a probe to gain insight into the charge creation mechanisms. In this Letter, we report the first results of such studies using the electric charge balance function in the relative pseudorapidity (d?) and azimuthal angle (df) in Pb-Pb collisions at sNN=2.76 TeV with the ALICE detector at the Large Hadron Collider. The width of the balance function decreases with growing centrality (i.e. for more central collisions) in both projections. This centrality dependence is not reproduced by HIJING, while AMPT, a model which incorporates strings and parton rescattering, exhibits qualitative agreement with the measured correlations in df but fails to describe the correlations in d?. A thermal blast-wave model incorporating local charge conservation and tuned to describe the pTspectra and v2measurements reported by ALICE, is used to fit the centrality dependence of the width of the balance function and to extract the average separation of balancing charges at freeze-out. The comparison of our results with measurements at lower energies reveals an ordering with sNN: the balance functions become narrower with increasing energy for all centralities. This is consistent with the effect of larger radial flow at the LHC energies but also with the late stage creation scenario of balancing charges. However, the relative decrease of the balance function widths in d? and df with centrality from the highest SPS to the LHC energy exhibits only small differences. This observation cannot be interpreted solely within the framework where the majority of the charge is produced at a later stage in the evolution of the heavy-ion collision.

U2 - 10.1016/j.physletb.2013.05.039

DO - 10.1016/j.physletb.2013.05.039

M3 - Journal article

SN - 0370-2693

VL - 723

SP - 267

EP - 279

JO - Physics Letters B: Particle Physics, Nuclear Physics and Cosmology

JF - Physics Letters B: Particle Physics, Nuclear Physics and Cosmology

IS - 4-5

ER -

Charge correlations using the balance function in Pb-Pb collisions at root s(NN)=2.76 TeV

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