Spin asymmetries for events with high<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>T</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>hadrons in DIS and an evaluation of the gluon polarization
B. AdevaDepartment of Particle Physics, University of Santiago, 15706 Santiago de Compostela, SpainE. ArıkBogazic i University and Istanbul Technical University, Istanbul, TurkeyA. ArvidsonDepartment of Radiation Sciences, Uppsala University, 75121 Uppsala, SwedenB. BadełekDepartment of Radiation Sciences, Uppsala University, 75121 Uppsala, SwedenG. BaumPhysics Department, University of Bielefeld, 33501 Bielefeld, GermanyP. BerglundHelsinki University of Technology, Low Temperature Laboratory and Institute of Particle Physics Technology, Espoo, FinlandL. BetevNow at University of California, Department of Physics, Los Angeles, CA 90024, USAR. BirsaDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyN. de BottonC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceF. BradamanteDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyA. BravarNow at Brookhaven National Laboratory, Upton, NY 11973, USA. ihA. BressanDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyS. BültmannPhysics Department, University of Bielefeld, 33501 Bielefeld, GermanyE. BurtinC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceDonald G. CrabbDepartment of Physics, University of Virginia, Charlottesville, Virginia 22901, USAJ. CranshawBonner Laboratory, Rice University, Houston, Texas 77251-1892, USAT. ÇuhadarNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsS. Dalla TorreDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyR. van DantzigNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsB. DerroDepartment of Physics, University of California, Los Angeles, California 90024, USAA. DeshpandeDepartment of Physics, Yale University, New Haven, Connecticut 06511, USAS. DhawanDepartment of Physics, Yale University, New Haven, Connecticut 06511, USAC. DulyaNow at CIEMAT, Avda Complutense 22, 28040, Madrid, SpainS. EichblattBonner Laboratory, Rice University, Houston, Texas 77251-1892, USAD. FaschingDepartment of Physics, Northwestern University, Evanston, Illinois 60208, USAF. FeinsteinC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceChristian FernandézDepartment of Particle Physics, University of Santiago, 15706 Santiago de Compostela, SpainB. FroisC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceA. GallasDepartment of Particle Physics, University of Santiago, 15706 Santiago de Compostela, SpainJ. A. GarzónDepartment of Particle Physics, University of Santiago, 15706 Santiago de Compostela, SpainH. GillyPhysics Department, University of Freiburg, 79104 Freiburg, GermanyM. GiorgiDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyE. von GoelerDepartment of Physics, Northeastern University, Boston, Massachusetts 02115, USAS. GoertzPhysics Department, University of Bochum, 44780 Bochum, GermanyG. GraciaDepartment of Particle Physics, University of Santiago, 15706 Santiago de Compostela, SpainN. De GrootNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsM. Große PerdekampDepartment of Physics, Yale University, New Haven, Connecticut 06511, USAK. HaftD. von HarrachUniversity of Mainz, Institute for Nuclear Physics, 55099 Mainz, GermanyT. HasegawaCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanP. HautleCERN, 1211 Geneva 23, SwitzerlandN. HayashiCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanC. A. HeuschCERN, 1211 Geneva 23, SwitzerlandN. HorikawaCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanV. W. HughesDepartment of Physics, Yale University, New Haven, Connecticut 06511, USAG. IgoDepartment of Physics, University of California, Los Angeles, California 90024, USAS. IshimotoCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanT. IwataCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanE. KabußUniversity of Mainz, Institute for Nuclear Physics, 55099 Mainz, GermanyA. KarevJINR, Dubna, RU-141980 Dubna, RussiaH.J. KesslerNow at SBC Warburg Dillon Read, CH-4002 Basel, SwitzerlandT. KetelNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsJ. KirylukNow at University of California, Department of Physics, Los Angeles, CA 90024, USAYu. KisselevJINR, Dubna, RU-141980 Dubna, RussiaL. KlostermannNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsK. KowalikSotan Institute for Nuclear Studies and Warsaw University, 00681 Warsaw, PolandA.M. KotzinianJINR, Dubna, RU-141980 Dubna, RussiaW. KrögerCERN, 1211 Geneva 23, SwitzerlandF. KunneC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceK. KurekSotan Institute for Nuclear Studies and Warsaw University, 00681 Warsaw, PolandJ. KyynäräinenHelsinki University of Technology, Low Temperature Laboratory and Institute of Particle Physics Technology, Espoo, FinlandM. LamannaDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyU. LandgrafPhysics Department, University of Freiburg, 79104 Freiburg, GermanyJ.M. Le GoffC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceF. LeharC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceA. de LesquenC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceJ. LichtenstadtSchool of Physics, Tel Aviv University, 69978 Tel Aviv, IsraelM. LitmaathNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsA. MagnonC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceAlexander MaltsevNow at CERN, 1211 Geneva 23, SwitzerlandF. MarieC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceA. MartinDepartment of Physics, INFN Trieste and University of Trieste, 34127 Trieste, ItalyJ. MartinoC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceT. MatsudaCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanB. MayesDepartment of Physics, and Institute for Beam Particle Dynamics, University of Houston, Houston, Texas 77204, USAJ. S. McCarthyDepartment of Physics, University of Virginia, Charlottesville, Virginia 22901, USAK. MedvedJINR, Dubna, RU-141980 Dubna, RussiaW. MeyerPhysics Department, University of Bochum, 44780 Bochum, GermanyD. H. MillerDepartment of Physics, Northwestern University, Evanston, Illinois 60208, USAY. MiyachiCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanK. MoriCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanJ. MoromisatoDepartment of Physics, Northeastern University, Boston, Massachusetts 02115, USAJ. NassalskiSotan Institute for Nuclear Studies and Warsaw University, 00681 Warsaw, PolandT. NiinikoskiCERN, 1211 Geneva 23, SwitzerlandJ.E.J. OberskiNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsA. OgawaCIRSE and Department of Physics, Nagoya University, Furo-Cho, Chikusa-Ku, 464 Nagoya, JapanC. ÖzbenBogazic i University and Istanbul Technical University, Istanbul, TurkeyH. PereiraC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceD. V. PeshekhonovJINR, Dubna, RU-141980 Dubna, RussiaR. PiegaiaDepartment of Physics, Yale University, New Haven, Connecticut 06511, USAL. PinskyDepartment of Physics, and Institute for Beam Particle Dynamics, University of Houston, Houston, Texas 77204, USAS. PlatchkovC.E.A. Saclay, DAPNIA, 91191 Gif-sur-Yvette, FranceM. PlóDepartment of Particle Physics, University of Santiago, 15706 Santiago de Compostela, SpainD. PoseJINR, Dubna, RU-141980 Dubna, RussiaH. PostmaNIKHEF, Delft University of Technology, FOM and Free University, 1009 AJ Amsterdam, The NetherlandsJ. PretzUniversity of Mainz, Institute for Nuclear Physics, 55099 Mainz, GermanyG. RädelPhysics Department, University of Bochum, 44780 Bochum, GermanyG. ReicherzPhysics Department, University of Bochum, 44780 Bochum, GermanyJ. RobertsPermanent address: Rice University, Bonner Laboratory, Hous-ton, TX 77251-1892, USAMiguel Á. RodríguezDepartment of Radiation Sciences, Uppsala University, 75121 Uppsala, Sweden
2004lv
ABI
Аннотация
We present a measurement of the longitudinal spin cross section asymmetry for deep-inelastic muon-nucleon interactions with two high transverse momentum hadrons in the final state. Two methods of event classification are used to increase the contribution of the photon-gluon fusion process to above 30%. The most effective one, based on a neural network approach, provides the asymmetries ${A}_{p}^{\mathcal{l}\stackrel{\ensuremath{\rightarrow}}{N}\mathcal{l}\mathrm{hhX}}=0.030\ifmmode\pm\else\textpm\fi{}0.057(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.010(\mathrm{syst})$ and ${A}_{d}^{\mathcal{l}\stackrel{\ensuremath{\rightarrow}}{N}\mathcal{l}\mathrm{hhX}}=0.070\ifmmode\pm\else\textpm\fi{}0.076(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.010(\mathrm{syst}).$ From these values we derive an averaged gluon polarization $\ensuremath{\Delta}G/G=\ensuremath{-}0.20\ifmmode\pm\else\textpm\fi{}0.28(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.10(\mathrm{syst})$ at an average fraction of nucleon momentum carried by gluons $〈\ensuremath{\eta}〉=0.07.$
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