Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV

S. Acharya; J. Adam; D. Adamova; J Adolfsson; MM. Aggarwal; G.A. Rinella; Maria Agnello; N. Agrawal; Z. Ahammed; N. Ahmad; S.U. Ahn; S. Aiola; M. Al-Turany; D. Aleksandrov; Rafael A. Molina; B Alessandro; A. Akindinov; DSD Albuquerque; S. Alam; A. Alici; A. Alkin; J. Alme; T. Alt; Ian Bearden; Christian Alexander Bourjau; Ante Bilandzic; Jens Jørgen Gaardhøje; Katarina Gajdosova; Marek Chojnacki; bsm989 bsm989; Christian Holm Christensen; Børge Svane Nielsen; Lais Ozelin De Lima Pimentel; Freja Thoresen; You Zhou

doi:10.1016/j.physletb.2017.12.021

Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV

S. Acharya, J. Adam, D. Adamova, J Adolfsson, MM. Aggarwal, G.A. Rinella, Maria Agnello, N. Agrawal, Z. Ahammed, N. Ahmad, S.U. Ahn, S. Aiola, M. Al-Turany, D. Aleksandrov, Rafael A. Molina, B Alessandro, A. Akindinov, DSD Albuquerque, S. Alam, A. AliciA. Alkin, J. Alme, T. Alt, Ian Bearden, Christian Alexander Bourjau, Ante Bilandzic, Jens Jørgen Gaardhøje, Katarina Gajdosova, Marek Chojnacki, bsm989 bsm989, Christian Holm Christensen, Børge Svane Nielsen, Lais Ozelin De Lima Pimentel, Freja Thoresen, You Zhou

Experimental Particle Physics

33 Citations (Scopus)

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Abstract

In ultrarelativistic heavy-ion collisions, the event-by-event variation of the elliptic flow v₂ reflects fluctuations in the shape of the initial state of the system. This allows to select events with the same centrality but different initial geometry. This selection technique, Event Shape Engineering, has been used in the analysis of charge-dependent two- and three-particle correlations in Pb–Pb collisions at s_NN=2.76 TeV. The two-particle correlator 〈cos⁡(φ_α−φ_β)〉 calculated for different combinations of charges α and β is almost independent of v₂ (for a given centrality), while the three-particle correlator 〈cos⁡(φ_α+φ_β−2Ψ₂)〉 scales almost linearly both with the event v₂ and charged-particle pseudorapidity density. The charge dependence of the three-particle correlator is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. However, its measured dependence on v₂ points to a large non-CME contribution to the correlator. Comparing the results with Monte Carlo calculations including a magnetic field due to the spectators, the upper limit of the CME signal contribution to the three-particle correlator in the 10–50% centrality interval is found to be 26–33% at 95% confidence level.

Original language	English
Journal	Physics Letters B
Volume	777
Pages (from-to)	151-162
Number of pages	12
ISSN	0370-2693
DOIs	https://doi.org/10.1016/j.physletb.2017.12.021
Publication status	Published - 10 Feb 2018

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Acharya, S., Adam, J., Adamova, D., Adolfsson, J., Aggarwal, MM., Rinella, G. A., Agnello, M., Agrawal, N., Ahammed, Z., Ahmad, N., Ahn, S. U., Aiola, S., Al-Turany, M., Aleksandrov, D., Molina, R. A., Alessandro, B., Akindinov, A., Albuquerque, DSD., Alam, S., ... Zhou, Y. (2018). Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV. Physics Letters B, 777, 151-162. https://doi.org/10.1016/j.physletb.2017.12.021

Acharya, S, Adam, J, Adamova, D, Adolfsson, J, Aggarwal, MM, Rinella, GA, Agnello, M, Agrawal, N, Ahammed, Z, Ahmad, N, Ahn, SU, Aiola, S, Al-Turany, M, Aleksandrov, D, Molina, RA, Alessandro, B, Akindinov, A, Albuquerque, DSD, Alam, S, Alici, A, Alkin, A, Alme, J, Alt, T, Bearden, I, Bourjau, CA, Bilandzic, A, Gaardhøje, JJ, Gajdosova, K, Chojnacki, M, bsm989, B , Christensen, CH , Nielsen, BS, Ozelin De Lima Pimentel, L, Thoresen, F & Zhou, Y 2018, 'Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV', Physics Letters B, vol. 777, pp. 151-162. https://doi.org/10.1016/j.physletb.2017.12.021

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title = "Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV",

abstract = "In ultrarelativistic heavy-ion collisions, the event-by-event variation of the elliptic flow v2 reflects fluctuations in the shape of the initial state of the system. This allows to select events with the same centrality but different initial geometry. This selection technique, Event Shape Engineering, has been used in the analysis of charge-dependent two- and three-particle correlations in Pb–Pb collisions at sNN=2.76 TeV. The two-particle correlator 〈cos⁡(φα−φβ)〉 calculated for different combinations of charges α and β is almost independent of v2 (for a given centrality), while the three-particle correlator 〈cos⁡(φα+φβ−2Ψ2)〉 scales almost linearly both with the event v2 and charged-particle pseudorapidity density. The charge dependence of the three-particle correlator is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. However, its measured dependence on v2 points to a large non-CME contribution to the correlator. Comparing the results with Monte Carlo calculations including a magnetic field due to the spectators, the upper limit of the CME signal contribution to the three-particle correlator in the 10–50% centrality interval is found to be 26–33% at 95% confidence level.",

author = "S. Acharya and J. Adam and D. Adamova and J Adolfsson and MM. Aggarwal and G.A. Rinella and Maria Agnello and N. Agrawal and Z. Ahammed and N. Ahmad and S.U. Ahn and S. Aiola and M. Al-Turany and D. Aleksandrov and Molina, {Rafael A.} and B Alessandro and A. Akindinov and DSD Albuquerque and S. Alam and A. Alici and A. Alkin and J. Alme and T. Alt and Ian Bearden and Bourjau, {Christian Alexander} and Ante Bilandzic and Gaardh{\o}je, {Jens J{\o}rgen} and Katarina Gajdosova and Marek Chojnacki and bsm989 bsm989 and Christensen, {Christian Holm} and Nielsen, {B{\o}rge Svane} and {Ozelin De Lima Pimentel}, Lais and Freja Thoresen and You Zhou",

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doi = "10.1016/j.physletb.2017.12.021",

language = "English",

volume = "777",

pages = "151--162",

journal = "Physics Letters B",

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T1 - Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV

AU - Acharya, S.

AU - Adam, J.

AU - Adamova, D.

AU - Adolfsson, J

AU - Aggarwal, MM.

AU - Rinella, G.A.

AU - Agnello, Maria

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahmad, N.

AU - Ahn, S.U.

AU - Aiola, S.

AU - Al-Turany, M.

AU - Aleksandrov, D.

AU - Molina, Rafael A.

AU - Alessandro, B

AU - Akindinov, A.

AU - Albuquerque, DSD

AU - Alam, S.

AU - Alici, A.

AU - Alkin, A.

AU - Alme, J.

AU - Alt, T.

AU - Bearden, Ian

AU - Bourjau, Christian Alexander

AU - Bilandzic, Ante

AU - Gaardhøje, Jens Jørgen

AU - Gajdosova, Katarina

AU - Chojnacki, Marek

AU - bsm989, bsm989

AU - Christensen, Christian Holm

AU - Nielsen, Børge Svane

AU - Ozelin De Lima Pimentel, Lais

AU - Thoresen, Freja

AU - Zhou, You

PY - 2018/2/10

Y1 - 2018/2/10

N2 - In ultrarelativistic heavy-ion collisions, the event-by-event variation of the elliptic flow v2 reflects fluctuations in the shape of the initial state of the system. This allows to select events with the same centrality but different initial geometry. This selection technique, Event Shape Engineering, has been used in the analysis of charge-dependent two- and three-particle correlations in Pb–Pb collisions at sNN=2.76 TeV. The two-particle correlator 〈cos⁡(φα−φβ)〉 calculated for different combinations of charges α and β is almost independent of v2 (for a given centrality), while the three-particle correlator 〈cos⁡(φα+φβ−2Ψ2)〉 scales almost linearly both with the event v2 and charged-particle pseudorapidity density. The charge dependence of the three-particle correlator is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. However, its measured dependence on v2 points to a large non-CME contribution to the correlator. Comparing the results with Monte Carlo calculations including a magnetic field due to the spectators, the upper limit of the CME signal contribution to the three-particle correlator in the 10–50% centrality interval is found to be 26–33% at 95% confidence level.

AB - In ultrarelativistic heavy-ion collisions, the event-by-event variation of the elliptic flow v2 reflects fluctuations in the shape of the initial state of the system. This allows to select events with the same centrality but different initial geometry. This selection technique, Event Shape Engineering, has been used in the analysis of charge-dependent two- and three-particle correlations in Pb–Pb collisions at sNN=2.76 TeV. The two-particle correlator 〈cos⁡(φα−φβ)〉 calculated for different combinations of charges α and β is almost independent of v2 (for a given centrality), while the three-particle correlator 〈cos⁡(φα+φβ−2Ψ2)〉 scales almost linearly both with the event v2 and charged-particle pseudorapidity density. The charge dependence of the three-particle correlator is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity violating effect of the strong interaction. However, its measured dependence on v2 points to a large non-CME contribution to the correlator. Comparing the results with Monte Carlo calculations including a magnetic field due to the spectators, the upper limit of the CME signal contribution to the three-particle correlator in the 10–50% centrality interval is found to be 26–33% at 95% confidence level.

U2 - 10.1016/j.physletb.2017.12.021

DO - 10.1016/j.physletb.2017.12.021

M3 - Journal article

SN - 0370-2693

VL - 777

SP - 151

EP - 162

JO - Physics Letters B

JF - Physics Letters B

ER -

Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at root s(NN)=2.76 TeV

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