Photoproduction of $D^{pm}$ Mesons in $ep$ Collisi

arXiv:hep-ex/9604005v123Apr1996DESY96-055April1996PhotoproductionofD∗±MesonsinElectron-ProtonCollisionsatHERAH1CollaborationAbstractAttheelectron-protoncolliderHERAtheinclusiveD∗±mesonphotoproduc-tioncrosssectionhasbeenmeasuredwiththeH1detectorintwodifferent,butpartlyoverlapping,kinematicalregions.Forthefirst,wherehWγpi≈200GeVandQ20.01GeV2,theresultisσ(γp→c¯cX)=(13.2±2.2+2.1−1.7+9.9−4.8)μb.Thesec-ondmeasurementforQ24GeV2yieldsσ(γp→c¯cX)=(9.3±2.1+1.9−1.8+6.9−3.2)μbathWγpi≈142GeVandσ(γp→c¯cX)=(20.6±5.5+4.3−3.9+15.4−7.2)μbathWγpi≈230GeV,respectively.Thethirderroraccountsforanadditionaluncertaintyduetotheprotonandphotonpartondensityparametrizations.DifferentialcrosssectionsarepresentedasafunctionoftheD∗±transversemomentumandrapidity.Theresultscomparereasonablywellwithnext-to-leadingorderQCDcalculations.Evidencefordiffractivephotoproductionofcharmquarksispresented.S.Aid14,V.Andreev26,B.Andrieu29,R.-D.Appuhn12,M.Arpagaus37,A.Babaev25,J.B¨ahr36,J.B´an18,Y.Ban28,P.Baranov26,E.Barrelet30,R.Barschke12,W.Bartel12,M.Barth5,U.Bassler30,H.P.Beck38,H.-J.Behrend12,A.Belousov26,Ch.Berger1,G.Bernardi30,R.Bernet37,G.Bertrand-Coremans5,M.Be-san¸con10,R.Beyer12,P.Biddulph23,P.Bispham23,J.C.Bizot28,V.Blobel14,K.Borras9,F.Botterweck5,V.Boudry29,A.Braemer15,W.Braunschweig1,V.Brisson28,D.Bruncko18,C.Brune16,R.Buchholz12,L.B¨ungener14,J.B¨urger12,F.W.B¨usser14,A.Buniatian12,39,S.Burke19,M.J.Burton23,G.Buschhorn27,A.J.Campbell12,T.Carli27,M.Charlet12,D.Clarke6,A.B.Clegg19,B.Clerbaux5,S.Cocks20,J.G.Contreras9,C.Cormack20,J.A.Coughlan6,A.Courau28,M.-C.Cousinou24,G.Cozzika10,L.Criegee12,D.G.Cussans6,J.Cvach31,S.Dagoret30,J.B.Dainton20,W.D.Dau17,K.Daum35,M.David10,C.L.Davis19,B.Delcourt28,A.DeRoeck12,E.A.DeWolf5,M.Dirkmann9,P.Dixon19,P.DiNezza33,W.Dlugosz8,C.Dollfus38,J.D.Dowell4,H.B.Dreis2,A.Droutskoi25,D.D¨ullmann14,O.D¨unger14,H.Duhm13,J.Ebert35,T.R.Ebert20,G.Eckerlin12,V.Efremenko25,S.Egli38,R.Eichler37,F.Eisele15,E.Eisenhandler21,R.J.Ellison23,E.Elsen12,M.Erdmann15,W.Erdmann37,E.Evrard5,A.B.Fahr14,L.Favart28,A.Fedotov25,D.Feeken14,R.Felst12,J.Feltesse10,J.Ferencei18,F.Ferrarotto33,K.Flamm12,M.Fleischer9,M.Flieser27,G.Fl¨ugge2,A.Fomenko26,B.Fominykh25,J.Form´anek32,J.M.Foster23,G.Franke12,E.Fretwurst13,E.Gabathuler20,K.Gabathuler34,F.Gaede27,J.Garvey4,J.Gayler12,M.Gebauer36,A.Gellrich12,H.Genzel1,R.Gerhards12,A.Glazov36,U.Goerlach12,L.Goerlich7,N.Gogitidze26,M.Goldberg30,D.Goldner9,K.Golec-Biernat7,B.Gonzalez-Pineiro30,I.Gorelov25,C.Grab37,H.Gr¨assler2,R.Gr¨assler2,T.Greenshaw20,R.K.Griffiths21,G.Grindhammer27,A.Gruber27,C.Gruber17,J.Haack36,T.Hadig1,D.Haidt12,L.Hajduk7,M.Hampel1,W.J.Haynes6,G.Heinzelmann14,R.C.W.Henderson19,H.Henschel36,I.Herynek31,M.F.Hess27,W.Hildesheim12,K.H.Hiller36,C.D.Hilton23,J.Hladk´y31,K.C.Hoeger23,M.H¨oppner9,D.Hoffmann12,T.Holtom20,R.Horisberger34,V.L.Hudgson4,M.H¨utte9,H.Hufnagel15,M.Ibbotson23,H.Itterbeck1,A.Jacholkowska28,C.Jacobsson22,M.Jaffre28,J.Janoth16,T.Jansen12,L.J¨onsson22,K.Johannsen14,D.P.Johnson5,L.Johnson19,H.Jung10,P.I.P.Kalmus21,M.Kander12,D.Kant21,R.Kaschowitz2,U.Kathage17,J.Katzy15,H.H.Kaufmann36,O.Kaufmann15,S.Kazarian12,I.R.Kenyon4,S.Kermiche24,C.Keuker1,C.Kiesling27,M.Klein36,C.Kleinwort12,G.Knies12,T.K¨ohler1,J.H.K¨ohne27,H.Kolanoski3,F.Kole8,S.D.Kolya23,V.Korbel12,M.Korn9,P.Kostka36,S.K.Kotelnikov26,T.Kr¨amerk¨amper9,M.W.Krasny7,30,H.Krehbiel12,D.Kr¨ucker2,U.Kr¨uger12,U.Kr¨uner-Marquis12,H.K¨uster22,M.Kuhlen27,T.Kurˇca36,J.Kurzh¨ofer9,D.Lacour30,B.Laforge10,R.Lander8,M.P.J.Landon21,W.Lange36,U.Langenegger37,J.-F.Laporte10,A.Lebedev26,F.Lehner12,C.Leverenz12,S.Levonian29,Ch.Ley2,G.Lindstr¨om13,M.Lindstroem22,J.Link8,F.Linsel12,J.Lipinski14,B.List12,G.Lobo28,H.Lohmander22,J.W.Lomas23,G.C.Lopez13,V.Lubimov25,D.L¨uke9,12,N.Magnussen35,E.Malinovski26,S.Mani8,R.Maraˇcek18,P.Marage5,J.Marks24,R.Marshall23,J.Martens35,G.Martin14,R.Martin20,H.-U.Martyn1,J.Martyniak7,T.Mavroidis21,S.J.Maxfield20,S.J.McMahon20,A.Mehta6,K.Meier16,T.Merz36,A.Meyer12,A.Meyer14,H.Meyer35,J.Meyer12,P.-O.Meyer2,A.Migliori29,S.Mikocki7,D.Milstead20,J.Moeck27,F.Moreau29,J.V.Morris6,E.Mroczko7,D.M¨uller38,G.M¨uller12,K.M¨uller12,P.Mur´ın18,V.Nagovizin25,R.Nahnhauer36,B.Naroska14,Th.Naumann36,P.R.Newman4,D.Newton19,D.Neyret30,H.K.Nguyen30,T.C.Nicholls4,F.Niebergall14,C.Niebuhr12,Ch.Niedzballa1,H.Niggli37,R.Nisius1,G.Nowak7,G.W.Noyes6,M.Nyberg-Werther22,M.Oakden20,H.Oberlack27,U.Obrock9,J.E.Olsson12,D.Ozerov25,P.Palmen2,E.Panaro12,A.Panitch5,C.Pascaud28,G.D.Patel20,H.Pawletta2,E.Peppel36,E.Perez10,J.P.Phillips20,A.Pieuchot24,D.Pitzl37,G.Pope8,S.Prell12,R.Prosi12,K.Rabbertz1,G.R¨adel12,F.Raupach1,P.Reimer31,S.Reinshagen12,H.Rick9,V.Riech13,J.Riedlberger37,F.Riepenhausen2,S.Riess14,E.Rizvi21,S.M.Robertson4,P.Robmann38,H.E.Roloff36,†,R.Roosen5,K.Rosenbauer1,A.Rostovtsev25,F.Rouse8,C.Royon10,K.R¨uter27,S.Rusakov26,K.Rybicki7,N.Sahlmann2,D.P.C.Sankey6,P.Schacht27,S.Schiek14,S.Schleif16,P.Schleper15,W.vonSchlippe21,D.Schmidt35,G.Schmidt14,A.Sch¨oning12,V.Schr¨oder12,E.Schuhmann27,B.Schwab15,F.Sefkow38,M.Seidel13,R.Sell12,A.Se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