Measurement of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math> Momentum and Angular Distributions from Linearly Polarized Photon Collisions
J. AdamBrookhaven National Laboratory, Upton, New York 11973L. AdamczykAGH University of Science and Technology, FPACS, Cracow 30-059, PolandJ. R. AdamsOhio State University, Columbus, Ohio 43210J. K. AdkinsUniversity of Kentucky, Lexington, Kentucky 40506-0055G. AgakishievJoint Institute for Nuclear Research, Dubna 141 980, RussiaM. M. AggarwalPanjab University, Chandigarh 160014, IndiaZ. AhammedVariable Energy Cyclotron Centre, Kolkata 700064, IndiaI. AlekseevAlikhanov Institute for Theoretical and Experimental Physics NRC “Kurchatov Institute,” Moscow 117218, RussiaD. M. AndersonTexas A&M University, College Station, Texas 77843A. AparinJoint Institute for Nuclear Research, Dubna 141 980, RussiaE. C. AschenauerBrookhaven National Laboratory, Upton, New York 11973M. U. AshrafCentral China Normal University, Wuhan, Hubei 430079F. G. AtetallaKent State University, Kent, Ohio 44242A. AttriPanjab University, Chandigarh 160014, IndiaG. S. AverichevJoint Institute for Nuclear Research, Dubna 141 980, RussiaV. BairathiIndian Institute of Science Education and Research (IISER), Berhampur 760010, IndiaK. N. BarishUniversity of California, Riverside, California 92521A. BeheraState University of New York, Stony Brook, New York 11794R. BellwiedUniversity of Houston, Houston, Texas 77204A. BhasinUniversity of Jammu, Jammu 180001, IndiaJ. BielčíkCzech Technical University in Prague, FNSPE, Prague 115 19, Czech RepublicJ. BielčíkováNuclear Physics Institute of the CAS, Rez 250 68, Czech RepublicL. C. BlandBrookhaven National Laboratory, Upton, New York 11973I. G. BordyuzhinAlikhanov Institute for Theoretical and Experimental Physics NRC “Kurchatov Institute,” Moscow 117218, RussiaJ. D. BrandenburgBrookhaven National Laboratory, Upton, New York 11973A. V. BrandinNational Research Nuclear University MEPhI, Moscow 115409, RussiaJ. M. ButterworthRice University, Houston, Texas 77251H. CainesYale University, New Haven, Connecticut 06520M. Calderon De La Barca SanchezUniversity of California, Davis, California 95616D. CebraUniversity of California, Davis, California 95616I. ChakaberiaBrookhaven National Laboratory, Upton, New York 11973P. ChaloupkaCzech Technical University in Prague, FNSPE, Prague 115 19, Czech RepublicB. K. ChanUniversity of California, Los Angeles, California 90095F-H. ChangNational Cheng Kung University, Tainan 70101Z. ChangBrookhaven National Laboratory, Upton, New York 11973N. Chankova-BunzarovaJoint Institute for Nuclear Research, Dubna 141 980, RussiaA. ChatterjeeCentral China Normal University, Wuhan, Hubei 430079D. ChenUniversity of California, Riverside, California 92521J. H. ChenFudan University, Shanghai 200433Xiang ChenUniversity of Science and Technology of China, Hefei, Anhui 230026Z. ChenShandong University, Qingdao, Shandong 266237J. ChengTsinghua University, Beijing 100084M. CherneyCreighton University, Omaha, Nebraska 68178M. ChevalierUniversity of California, Riverside, California 92521S. ChoudhuryFudan University, Shanghai 200433W. ChristieBrookhaven National Laboratory, Upton, New York 11973H. J. CrawfordUniversity of California, Berkeley, California 94720M. CsanádELTE Eötvös Loránd University, Budapest H-1117, HungaryM. DaugherityAbilene Christian University, Abilene, Texas 79699T. G. DedovichJoint Institute for Nuclear Research, Dubna 141 980, RussiaI. M. DeppnerUniversity of Heidelberg, Heidelberg 69120, GermanyA. A. DerevschikovNRC “Kurchatov Institute”, Institute of High Energy Physics, Protvino 142281, RussiaL. DidenkoBrookhaven National Laboratory, Upton, New York 11973X. DongLawrence Berkeley National Laboratory, Berkeley, California 94720J. L. DrachenbergAbilene Christian University, Abilene, Texas 79699J. C. DunlopBrookhaven National Laboratory, Upton, New York 11973T. EdmondsPurdue University, West Lafayette, Indiana 47907N. ElseyWayne State University, Detroit, Michigan 48201J. EngelageUniversity of California, Berkeley, California 94720G. EppleyRice University, Houston, Texas 77251R. EshaState University of New York, Stony Brook, New York 11794S. EsumiUniversity of Tsukuba, Tsukuba, Ibaraki 305-8571, JapanO. EvdokimovUniversity of Illinois at Chicago, Chicago, Illinois 60607A. EwiglebenLehigh University, Bethlehem, Pennsylvania 18015O. EyserBrookhaven National Laboratory, Upton, New York 11973R. FatemiUniversity of Kentucky, Lexington, Kentucky 40506-0055S. FazioBrookhaven National Laboratory, Upton, New York 11973P. FedericNuclear Physics Institute of the CAS, Rez 250 68, Czech RepublicJ. FedorišinJoint Institute for Nuclear Research, Dubna 141 980, RussiaC. FengNational Cheng Kung University, Tainan 70101Y. FengPurdue University, West Lafayette, Indiana 47907P. FilipJoint Institute for Nuclear Research, Dubna 141 980, RussiaE. FinchSouthern Connecticut State University, New Haven, Connecticut 06515Y. FisyakBrookhaven National Laboratory, Upton, New York 11973A. FranciscoYale University, New Haven, Connecticut 06520Ł. FulekAGH University of Science and Technology, FPACS, Cracow 30-059, PolandC. A. GagliardiTexas A&M University, College Station, Texas 77843T. GalatyukTechnische Universität Darmstadt, Darmstadt 64289, GermanyF. J. M. GeurtsRice University, Houston, Texas 77251S. M. GibsonValparaiso University, Valparaiso, Indiana 46383K. GopalIndian Institute of Science Education and Research (IISER) Tirupati, Tirupati 517507, IndiaD. GrosnickValparaiso University, Valparaiso, Indiana 46383A. I. HamadKent State University, Kent, Ohio 44242A. HamedAmerican University of Cairo, New Cairo, New Cairo 11835, EgyptJ. W. HarrisYale University, New Haven, Connecticut 06520S. HeCentral China Normal University, Wuhan, Hubei 430079W. HeFudan University, Shanghai 200433S. HeppelmannPennsylvania State University, University Park, Pennsylvania 16802S. HeppelmannPennsylvania State University, University Park, Pennsylvania 16802N. HerrmannUniversity of Heidelberg, Heidelberg 69120, GermanyE. HoffmanUniversity of Houston, Houston, Texas 77204L. HolubCzech Technical University in Prague, FNSPE, Prague 115 19, Czech RepublicY. HongLawrence Berkeley National Laboratory, Berkeley, California 94720S. HorvatYale University, New Haven, Connecticut 06520Y. HuFudan University, Shanghai 200433H. Z. HuangUniversity of California, Los Angeles, California 90095S. L. HuangStony Brook UniversityTao HuangNational Cheng Kung University, Tainan 70101Xiaojin HuangTsinghua University, Beijing 100084
2021lv
ABI
Аннотация
The Breit-Wheeler process which produces matter and antimatter from photon collisions is experimentally investigated through the observation of 6085 exclusive electron-positron pairs in ultraperipheral $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. The measurements reveal a large fourth-order angular modulation of $\mathrm{cos}4\mathrm{\ensuremath{\Delta}}\ensuremath{\phi}=(16.8\ifmmode\pm\else\textpm\fi{}2.5)%$ and smooth invariant mass distribution absent of vector mesons ($\ensuremath{\phi}$, $\ensuremath{\omega}$, and $\ensuremath{\rho}$) at the experimental limit of $\ensuremath{\le}0.2%$ of the observed yields. The differential cross section as a function of ${e}^{+}{e}^{\ensuremath{-}}$ pair transverse momentum ${P}_{\ensuremath{\perp}}$ peaks at low value with $\sqrt{⟨{P}_{\ensuremath{\perp}}^{2}⟩}=38.1\ifmmode\pm\else\textpm\fi{}0.9\text{ }\text{ }\mathrm{MeV}$ and displays a significant centrality dependence. These features are consistent with QED calculations for the collision of linearly polarized photons quantized from the extremely strong electromagnetic fields generated by the highly charged Au nuclei at ultrarelativistic speed. The experimental results have implications for vacuum birefringence and for mapping the magnetic field which is important for emergent QCD phenomena.
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