The cross section for open-beauty production in photon-photon collisions is measured using the whole high-energy and high-luminosity data sample collected by the L3 detector at LEP. This corresponds to 627/pb of integrated luminosity for electron-positron

1III.PhysikalischesInstitut,RWTH,D-52056Aachen,Germany§

2NationalInstituteforHighEnergyPhysics,NIKHEF,andUniversityofAmsterdam,NL-1009DBAmsterdam,TheNetherlands

3UniversityofMichigan,AnnArbor,MI48109,USA

4Laboratoired’Annecy-le-VieuxdePhysiquedesParticules,LAPP,IN2P3-CNRS,BP110,F-74941Annecy-le-VieuxCEDEX,France

5InstituteofPhysics,UniversityofBasel,CH-4056Basel,Switzerland6LouisianaStateUniversity,BatonRouge,LA70803,USA

7InstituteofHighEnergyPhysics,IHEP,100039Beijing,China△

8UniversityofBolognaandINFN-SezionediBologna,I-40126Bologna,Italy9TataInstituteofFundamentalResearch,Mumbai(Bombay)400005,India10NortheasternUniversity,Boston,MA02115,USA

11InstituteofAtomicPhysicsandUniversityofBucharest,R-76900Bucharest,Romania

12CentralResearchInstituteforPhysicsoftheHungarianAcademyofSciences,H-1525Budapest114,Hungary 13MassachusettsInstituteofTechnology,Cambridge,MA02139,USA14PanjabUniversity,Chandigarh160014,India15KLTE-ATOMKI,H-4010Debrecen,Hungary¶

16DepartmentofExperimentalPhysics,UniversityCollegeDublin,Bel eld,Dublin4,Ireland17INFNSezionediFirenzeandUniversityofFlorence,I-50125Florence,Italy

18EuropeanLaboratoryforParticlePhysics,CERN,CH-1211Geneva23,Switzerland19WorldLaboratory,FBLJAProject,CH-1211Geneva23,Switzerland20UniversityofGeneva,CH-1211Geneva4,Switzerland21UniversityofHamburg,D-22761Hamburg,Germany

22ChineseUniversityofScienceandTechnology,USTC,Hefei,Anhui230029,China△23UniversityofLausanne,CH-1015Lausanne,Switzerland24InstitutdePhysiqueNucl´eairedeLyon,IN2P3-CNRS,Universit´eClaudeBernard,F-69622Villeurbanne,France25CentrodeInvestigacionesEnerg´eticas,MedioambientalesyTecnol´ogicas,CIEMAT,E-28040Madrid,Spain 26FloridaInstituteofTechnology,Melbourne,FL32901,USA27INFN-SezionediMilano,I-20133Milan,Italy

28InstituteofTheoreticalandExperimentalPhysics,ITEP,Moscow,Russia29INFN-SezionediNapoliandUniversityofNaples,I-80125Naples,Italy30DepartmentofPhysics,UniversityofCyprus,Nicosia,Cyprus

31RadboudUniversityandNIKHEF,NL-6525EDNijmegen,TheNetherlands32CaliforniaInstituteofTechnology,Pasadena,CA91125,USA33INFN-SezionediPerugiaandUniversit`aDegliStudidiPerugia,I-06100Perugia,Italy34NuclearPhysicsInstitute,St.Petersburg,Russia

35CarnegieMellonUniversity,Pittsburgh,PA15213,USA

36INFN-SezionediNapoliandUniversityofPotenza,I-85100Potenza,Italy37PrincetonUniversity,Princeton,NJ08544,USA38UniversityofCaliforna,Riverside,CA92521,USA

39INFN-SezionediRomaandUniversityofRome,“LaSapienza”,I-00185Rome,Italy40UniversityandINFN,Salerno,I-84100Salerno,Italy41UniversityofCalifornia,SanDiego,CA92093,USA

42BulgarianAcademyofSciences,CentralLab.ofMechatronicsandInstrumentation,BU-1113So a,Bulgaria43TheCenterforHighEnergyPhysics,KyungpookNationalUniversity,702-701Taegu,RepublicofKorea44NationalCentralUniversity,Chung-Li,Taiwan,China

45DepartmentofPhysics,NationalTsingHuaUniversity,Taiwan,China46PurdueUniversity,WestLafayette,IN47907,USA

47PaulScherrerInstitut,PSI,CH-5232Villigen,Switzerland48DESY,D-15738Zeuthen,Germany49Eidgen¨ossischeTechnischeHochschule,ETHZ¨urich,CH-8093Z¨urich,Switzerland§SupportedbytheGermanBundesministeriumf¨urBildung,Wissenschaft,ForschungundTechnologie. SupportedbytheHungarianOTKAfundundercontractnumbersT019181,F023259andT037350.¶AlsosupportedbytheHungarianOTKAfundundercontractnumberT026178. SupportedalsobytheComisi´onInterministerialdeCienciayTecnolog´ a.

AlsosupportedbyCONICETandUniversidadNacionaldeLaPlata,CC67,1900LaPlata,Argentina.△SupportedbytheNationalNaturalScienceFoundationofChina.