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arXiv · 1009.0505

Cross Section and Parity Violating Spin Asymmetries of W^+/- Boson Production in Polarized p+p Collisions at sqrt(s)=500 GeV

A. Adare·S. Afanasiev·C. Aidala·N. N. Ajitanand·Y. Akiba·R. Akimoto·J. Alexander·H. Al-Taani·K. R. Andrews·A. Angerami·K. Aoki·N. Apadula·E. Appelt·Y. Aramaki·R. Armendariz·E. C. Aschenauer·T. C. Awes·B. Azmoun·V. Babintsev·M. Bai·B. Bannier·K. N. Barish·B. Bassalleck·A. T. Basye·S. Bathe·V. Baublis·C. Baumann·A. Bazilevsky·R. Belmont·R. Bennett·A. Berdnikov·Y. Berdnikov·D. S. Blau·J. S. Bok·K. Boyle·M. L. Brooks·H. Buesching·V. Bumazhnov·G. Bunce·S. Butsyk·S. Campbell·A. Caringi·C. -H. Chen·C. Y. Chi·M. Chiu·I. J. Choi·J. B. Choi·R. K. Choudhury·P. Christiansen·T. Chujo·O. Chvala·V. Cianciolo·Z. Citron·B. A. Cole·Z. Conesa del Valle·M. Connors·M. Csanád·T. Csörgő·S. Dairaku·A. Datta·G. David·M. K. Dayananda·A. Denisov·A. Deshpande·E. J. Desmond·K. V. Dharmawardane·O. Dietzsch·A. Dion·M. Donadelli·L. D Orazio·O. Drapier·A. Drees·K. A. Drees·J. M. Durham·A. Durum·Y. V. Efremenko·T. Engelmore·A. Enokizono·H. En'yo·S. Esumi·B. Fadem·D. E. Fields·M. Finger Jr.·M. Finger·F. Fleuret·S. L. Fokin·J. E. Frantz·A. Franz·A. D. Frawley·Y. Fukao·T. Fusayasu·I. Garishvili·A. Glenn·M. Gonin·Y. Goto·R. Granier de Cassagnac·N. Grau·S. V. Greene·M. Grosse Perdekamp·T. Gunji
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Abstract

Large parity violating longitudinal single spin asymmetries A^{e^-}_L= -0.86^{+0.14}_{-0.30} and A^{e^+}_L= 0.88^{+0.12}_{-0.71} are observed for inclusive high transverse momentum electrons and positrons in polarized pp collisions at a center of mass energy of \sqrt{s}=500\ GeV with the PHENIX detector at RHIC. These e^{+/-} come mainly from the decay of W^{+/-} and Z^0 bosons, and the asymmetries directly demonstrate parity violation in the couplings of the W^{\pm} to the light quarks. The observed electron and positron yields were used to estimate W^\pm boson production cross sections equal to σ(pp \to W^+ X) \times BR(W^ \to ν_e)= 144.1+/-21.2(stat)^{+3.4}_{-10.3}(syst) +/- 15%(norm) pb, and σ(pp \to W^{-}X) \times BR(W^\to e^-\bar{ν_e}) = 31.7+/-12.1(stat)^{+10.1}_{-8.2}(syst)+/-15%(norm) pb.

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A. Adare, S. Afanasiev, C. Aidala, N. N. Ajitanand, Y. Akiba, R. Akimoto, J. Alexander, H. Al-Taani, K. R. Andrews, A. Angerami, K. Aoki, N. Apadula, E. Appelt, Y. Aramaki, R. Armendariz, E. C. Aschenauer, T. C. Awes, B. Azmoun, V. Babintsev, M. Bai, B. Bannier, K. N. Barish, B. Bassalleck, A. T. Basye, S. Bathe, V. Baublis, C. Baumann, A. Bazilevsky, R. Belmont, R. Bennett, A. Berdnikov, Y. Berdnikov, D. S. Blau, J. S. Bok, K. Boyle, M. L. Brooks, H. Buesching, V. Bumazhnov, G. Bunce, S. Butsyk, S. Campbell, A. Caringi, C. -H. Chen, C. Y. Chi, M. Chiu, I. J. Choi, J. B. Choi, R. K. Choudhury, P. Christiansen, T. Chujo, O. Chvala, V. Cianciolo, Z. Citron, B. A. Cole, Z. Conesa del Valle, M. Connors, M. Csanád, T. Csörgő, S. Dairaku, A. Datta, G. David, M. K. Dayananda, A. Denisov, A. Deshpande, E. J. Desmond, K. V. Dharmawardane, O. Dietzsch, A. Dion, M. Donadelli, L. D Orazio, O. Drapier, A. Drees, K. A. Drees, J. M. Durham, A. Durum, Y. V. Efremenko, T. Engelmore, A. Enokizono, H. En'yo, S. Esumi, B. Fadem, D. E. Fields, M. Finger Jr., M. Finger, F. Fleuret, S. L. Fokin, J. E. Frantz, A. Franz, A. D. Frawley, Y. Fukao, T. Fusayasu, I. Garishvili, A. Glenn, M. Gonin, Y. Goto, R. Granier de Cassagnac, N. Grau, S. V. Greene, M. Grosse Perdekamp, T. Gunji. 2010-09-03. Cross Section and Parity Violating Spin Asymmetries of W^+/- Boson Production in Polarized p+p Collisions at sqrt(s)=500 GeV. https://doi.org/10.1103/physrevlett.106.062001

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