Jet production in ep collisions at low Q 2 and determination of α s

F D Aaron,D Sunar,A J Campbell,G Cozzika,E A De Wolf,G Buschhorn,J Gayler,K Begzsuren,M Fleischer,L N Shtarkov,V Efremenko,N Loktionova,G Li,E Gabathuler,A Dubak,A Glazov,L Goerlich,O Pejchal,R Felst,J Žáček,Y Soloviev,R Roosen,A Dossanov,L Bystritskaya,G Laštovička-Medin,P Truöl,I Milcewicz-Mika,A Lebedev,M Kraemer,V Chekelian,E Hennekemper,I Tsakov,D Wegener,G Herrera,A Falkiewicz,A Cholewa,D P C Sankey,J Turnau,F Tomasz,S Ghazaryan,A Raspiareza,M Jacquet,W Bartel,V Tchoulakov,I R Kenyon,K H Hiller,S Shushkevich,V Brisson,D Haidt,C Niebuhr,F Moreau,J B Dainton,A Makankine,V Lendermann,E Malinovski,T Greenshaw,H Zohrabyan,M Mudrinic,B Delcourt,T N Trinh,V Dodonov,A Petrukhin,G D Patel,K Krastev,S Egli,D Traynor,A Rostovtsev,E Barrelet,P Sopicki,A Valkárová,A Bunyatyan,K Müller,B Stella,N Gogitidze,M Steder,D Ozerov,V Lubimov,A Baghdasaryan,Y Vazdik,J Ferencei,J Feltesse,T Kluge,E Wünsch,P D Thompson,V Spaskov,J E Olsson,P Van Mechelen,R Plačakytė,A Specka,C Pascaud,V Volchinski,K Daum,B Tseepeldorj,T Toll,M Kapichine,J Cvach,S Mikocki,K Urban,P Kostka,G Grindhammer,C Vallée,K Nowak,R C W Henderson,U Straumann,S Habib,A Nikiforov,S Vinokurova,S Levonian,C Kiesling,B R Grell,J Delvax,T Ravdandorj,Z Staykova,F Sefkow,H Henschel,G Nowak,K B Cantun Avila ,P Laycock,E Rizvi,A Fedotov,G Eckerlin,S Schmitt,J V Morris,Michal Deák ,J Meyer,Th D Papadopoulou ,L Marti ,A Schöning,A Zhokin,M Herbst,D Pitzl,A Knutsson,Krzysztof Kutak ,P Marage,J G Contreras,D Hoffmann,T Sloan,D South,B Roland,A Belousov,K Černý ,J Kretzschmar,R Kogler,C Wissing ,E Elsen,П Мурін ,J Katzy,J.c Bizot ,L Favart,P Robmann,M Klein,X Janssen,T Naumann ,G Stoicea,J Zálešâk ,P Reimer,C Kleinwort,I Smiljanić ,W Lange,M Sauter,A Vargas Trevino ,D Šálek,P R Newman,E Pérez ,B Pokorny,T Hreus,R Horisberger,S M Piec ,J A Coughlan,A Liptaj,J Braciník ,V Černý ,M P J Landon,V Andreev,N Raičević ,A Kropivnitskaya,E Sauvan,C Helebrant,A Eliseev,C Diaconu,H Meyer,H.‐C Schultz‐Coulon ,S V Rusakov ,T Sýkora ,R.n Shaw-West ,Martin Brinkmann ,M Von Den Driesch ,A Morozov,M U Mozer,F Zomer,S J Maxfield,I Panagoulias,A J Rahmat,Bogdan Povh ,A W Jung,L Schoeffel,A Mehta,M Pandurović ,A Meyer ,G Thompson,I Pićurić ,M Rotaru,C Grab,D Nikitin,R López-Fernández ,R Polifka,M Gouzevitch,L Jönsson,I Glushkov,M Hildebrandt,S Osman,V Boudry,H U Martyn ,K Lipka,A Fomenko,B Antunović ,D Bruncko,Jenny List ,D Fischer ,B List,G Brandt,J E Ruiz Tabasco ,Zhiqing Philippe Zhang ,Edward Kosior ,Null Author_Id ,V Palichik,T Zimmermann,T H Tran,S Backović ,K Krüger,H Jung,I Božović-Jelisavc̆ić ,C Alexa,V Radescu

doi:10.1140/epjc/s10052-010-1282-x

Abstract

The production of jets is studied in deep-inelastic e+p scattering at low negative four momentum transfer squared 5<Q^2<100 GeV^2 and at inelasticity 0.2<y<0.7 using data recorded by the H1 detector at HERA in the years 1999 and 2000, corresponding to an integrated luminosity of 43.5 pb^-1. Inclusive jet, 2-jet and 3-jet cross sections as well as the ratio of 3-jet to 2-jet cross sections are measured as a function of Q^2 and jet transverse momentum. The 2-jet cross section is also measured as a function of the proton momentum fraction xi. The measurements are well described by perturbative quantum chromodynamics at next-to-leading order corrected for hadronisation effects and are subsequently used to extract the strong coupling alpha_s.

Full Text