Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ0 photoproduction in Pb–Pb collisions at sNN=5.02 TeV

ALICE Collaboration

doi:10.1016/j.physletb.2024.139017

Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ⁰ photoproduction in Pb–Pb collisions at s_NN=5.02 TeV

ALICE Collaboration

Relativistic Nuclear Physics

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

2 Scopus citations

Abstract

This Letter presents the first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ⁰ mesons. The ρ⁰ mesons are reconstructed through their decay into pion pairs. The measured anisotropy corresponds to the amplitude of the cos⁡(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb–Pb collisions at a center-of-mass energy of s_NN=5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos⁡(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations describe the measured cos⁡(2ϕ) anisotropy and its impact-parameter dependence as the result of a quantum interference effect at the femtometer scale, arising from the ambiguity regarding which of the nuclei is the photon source in the interaction.

Original language	English
Article number	139017
Journal	Physics Letters B
Volume	858
DOIs	https://doi.org/10.1016/j.physletb.2024.139017
State	Published - Nov 2024

Funding

The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung f\u00FCr Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Cient\u00EDfico e Tecnol\u00F3gico (CNPq), Financiadora de Estudos e Projetos (Finep), Funda\u00E7\u00E3o de Amparo \u00E0 Pesquisa do Estado de S\u00E3o Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Bulgarian Ministry of Education and Science, within the National Roadmap for Research Infrastructures 2020-2027 (object CERN), Bulgaria; Ministry of Education of China (MOEC), Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnol\u00F3gicas y Desarrollo Nuclear (CEADEN), Cubaenerg\u00EDa, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the VILLUM FONDEN and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat \u00E0 l'Energie Atomique (CEA) and Institut National de Physique Nucl\u00E9aire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium f\u00FCr Bildung und Forschung (BMBF) and GSI Helmholtzzentrum f\u00FCr Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; National Research and Innovation Agency - BRIN, Indonesia; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnolog\u00EDa, through Fondo de Cooperaci\u00F3n Internacional en Ciencia y Tecnolog\u00EDa (FONCICYT) and Direcci\u00F3n General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Pontificia Universidad Cat\u00F3lica del Per\u00FA, Peru; Ministry of Science and Higher Education, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics, Ministry of Research and Innovation and Institute of Atomic Physics and Universitatea Nationala de Stiinta si Tehnologie Politehnica Bucuresti, Romania; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSTDA) and National Science, Research and Innovation Fund (NSRF via PMU-B B05F650021), Thailand; Turkish Energy, Nuclear and Mineral Research Agency (TENMAK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America. In addition, individual groups or members have received support from: Czech Science Foundation (grant no. 23-07499S), Czech Republic; European Research Council (grant no. 950692), European Union; ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, European Union - NextGenerationEU; Academy of Finland (Center of Excellence in Quark Matter) (grant nos. 346327, 346328), Finland. The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centers and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung f\u00FCr Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Cient\u00EDfico e Tecnol\u00F3gico (CNPq), Financiadora de Estudos e Projetos (Finep), Funda\u00E7\u00E3o de Amparo \u00E0 Pesquisa do Estado de S\u00E3o Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Bulgarian Ministry of Education and Science, within the National Roadmap for Research Infrastructures 2020-2027 (object CERN), Bulgaria; Ministry of Education of China (MOEC), Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnol\u00F3gicas y Desarrollo Nuclear (CEADEN), Cubaenerg\u00EDa, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the Villum Fonden and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat \u00E0 l'\u00C9nergie Atomique (CEA) and Institut National de Physique Nucl\u00E9aire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium f\u00FCr Bildung und Forschung (BMBF) and GSI Helmholtzzentrum f\u00FCr Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy, Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; National Research and Innovation Agency - BRIN, Indonesia; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnolog\u00EDa, through Fondo de Cooperaci\u00F3n Internacional en Ciencia y Tecnolog\u00EDa (FONCICYT) and Direcci\u00F3n General de Asuntos del Personal Acad\u00E9mico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)), Netherlands; The Research Council of Norway, Norway; Pontificia Universidad Cat\u00F3lica del Per\u00FA, Peru; Ministry of Science and Higher Education, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics, Ministry of Research and Innovation and Institute of Atomic Physics and Universitatea Nationala de Stiinta si Tehnologie Politehnica Bucuresti, Romania; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSTDA) and National Science, Research and Innovation Fund (NSRF via PMU-B B05F650021), Thailand; Turkish Energy, Nuclear and Mineral Research Agency (TENMAK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America. In addition, individual groups or members have received support from: Czech Science Foundation (grant no. 23-07499S), Czech Republic; European Research Council (grant no. 950692), European Union; ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, European Union - NextGenerationEU; Academy of Finland (Center of Excellence in Quark Matter) (grant nos. 346327, 346328), Finland.

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10.1016/j.physletb.2024.139017

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@article{8a47f627a1bf4e26b7fec486ac7bafcf,

title = "Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ0 photoproduction in Pb–Pb collisions at sNN=5.02 TeV",

abstract = "This Letter presents the first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ0 mesons. The ρ0 mesons are reconstructed through their decay into pion pairs. The measured anisotropy corresponds to the amplitude of the cos⁡(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb–Pb collisions at a center-of-mass energy of sNN=5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos⁡(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations describe the measured cos⁡(2ϕ) anisotropy and its impact-parameter dependence as the result of a quantum interference effect at the femtometer scale, arising from the ambiguity regarding which of the nuclei is the photon source in the interaction.",

author = "{ALICE Collaboration} and S. Acharya and D. Adamov{\'a} and A. Agarwal and {Aglieri Rinella}, G. and L. Aglietta and M. Agnello and N. Agrawal and Z. Ahammed and S. Ahmad and Ahn, {S. U.} and I. Ahuja and A. Akindinov and V. Akishina and M. Al-Turany and D. Aleksandrov and B. Alessandro and Alfanda, {H. M.} and {Alfaro Molina}, R. and B. Ali and A. Alici and N. Alizadehvandchali and A. Alkin and J. Alme and G. Alocco and T. Alt and Altamura, {A. R.} and I. Altsybeev and Alvarado, {J. R.} and Alvarez, {C. O.R.} and Anaam, {M. N.} and C. Andrei and N. Andreou and A. Andronic and E. Andronov and V. Anguelov and F. Antinori and P. Antonioli and N. Apadula and L. Aphecetche and H. Appelsh{\"a}user and C. Arata and S. Arcelli and M. Aresti and R. Arnaldi and Arneiro, {J. G.M.C.A.} and Arsene, {I. C.} and F. Bock and Read, {K. F.} and J. Schambach and Schmidt, {N. V.}",

note = "Publisher Copyright: {\textcopyright} 2024 CERN for the benefit of the ALICE Collaboration",

year = "2024",

month = nov,

doi = "10.1016/j.physletb.2024.139017",

language = "English",

volume = "858",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier",

}

TY - JOUR

T1 - Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ0 photoproduction in Pb–Pb collisions at sNN=5.02 TeV

AU - ALICE Collaboration

AU - Acharya, S.

AU - Adamová, D.

AU - Agarwal, A.

AU - Aglieri Rinella, G.

AU - Aglietta, L.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahmad, S.

AU - Ahn, S. U.

AU - Ahuja, I.

AU - Akindinov, A.

AU - Akishina, V.

AU - Al-Turany, M.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alfanda, H. M.

AU - Alfaro Molina, R.

AU - Ali, B.

AU - Alici, A.

AU - Alizadehvandchali, N.

AU - Alkin, A.

AU - Alme, J.

AU - Alocco, G.

AU - Alt, T.

AU - Altamura, A. R.

AU - Altsybeev, I.

AU - Alvarado, J. R.

AU - Alvarez, C. O.R.

AU - Anaam, M. N.

AU - Andrei, C.

AU - Andreou, N.

AU - Andronic, A.

AU - Andronov, E.

AU - Anguelov, V.

AU - Antinori, F.

AU - Antonioli, P.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arata, C.

AU - Arcelli, S.

AU - Aresti, M.

AU - Arnaldi, R.

AU - Arneiro, J. G.M.C.A.

AU - Arsene, I. C.

AU - Bock, F.

AU - Read, K. F.

AU - Schambach, J.

AU - Schmidt, N. V.

PY - 2024/11

Y1 - 2024/11

N2 - This Letter presents the first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ0 mesons. The ρ0 mesons are reconstructed through their decay into pion pairs. The measured anisotropy corresponds to the amplitude of the cos⁡(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb–Pb collisions at a center-of-mass energy of sNN=5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos⁡(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations describe the measured cos⁡(2ϕ) anisotropy and its impact-parameter dependence as the result of a quantum interference effect at the femtometer scale, arising from the ambiguity regarding which of the nuclei is the photon source in the interaction.

AB - This Letter presents the first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ0 mesons. The ρ0 mesons are reconstructed through their decay into pion pairs. The measured anisotropy corresponds to the amplitude of the cos⁡(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb–Pb collisions at a center-of-mass energy of sNN=5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos⁡(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations describe the measured cos⁡(2ϕ) anisotropy and its impact-parameter dependence as the result of a quantum interference effect at the femtometer scale, arising from the ambiguity regarding which of the nuclei is the photon source in the interaction.

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U2 - 10.1016/j.physletb.2024.139017

DO - 10.1016/j.physletb.2024.139017

M3 - Article

AN - SCOPUS:85204389624

SN - 0370-2693

VL - 858

JO - Physics Letters B

JF - Physics Letters B

M1 - 139017

ER -

Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ⁰ photoproduction in Pb–Pb collisions at s_NN=5.02 TeV

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