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arXiv · 1906.02740

Longitudinal double-spin asymmetry for inclusive jet and dijet production in $pp$ collisions at $\sqrt{s} = 510$ GeV

STAR Collaboration·J. Adam·L. Adamczyk·J. R. Adams·J. K. Adkins·G. Agakishiev·M. M. Aggarwal·Z. Ahammed·I. Alekseev·D. M. Anderson·R. Aoyama·A. Aparin·D. Arkhipkin·E. C. Aschenauer·M. U. Ashraf·F. Atetalla·A. Attri·G. S. Averichev·V. Bairathi·K. Barish·A. J. Bassill·A. Behera·R. Bellwied·A. Bhasin·A. K. Bhati·J. Bielcik·J. Bielcikova·L. C. Bland·I. G. Bordyuzhin·J. D. Brandenburg·A. V. Brandin·J. Bryslawskyj·I. Bunzarov·J. Butterworth·H. Caines·M. Calderón de la Barca Sánchez·D. Cebra·I. Chakaberia·P. Chaloupka·B. K. Chan·F-H. Chang·Z. Chang·N. Chankova-Bunzarova·A. Chatterjee·S. Chattopadhyay·J. H. Chen·X. Chen·J. Cheng·M. Cherney·W. Christie·H. J. Crawford·M. Csanád·S. Das·T. G. Dedovich·I. M. Deppner·A. A. Derevschikov·L. Didenko·C. Dilks·X. Dong·J. L. Drachenberg·J. C. Dunlop·T. Edmonds·N. Elsey·J. Engelage·G. Eppley·R. Esha·S. Esumi·O. Evdokimov·J. Ewigleben·O. Eyser·R. Fatemi·S. Fazio·P. Federic·J. Fedorisin·Y. Feng·P. Filip·E. Finch·Y. Fisyak·L. Fulek·C. A. Gagliardi·T. Galatyuk·F. Geurts·A. Gibson·K. Gopal·D. Grosnick·A. Gupta·W. Guryn·A. I. Hamad·A. Hamed·J. W. Harris·L. He·S. Heppelmann·N. Herrmann·L. Holub·Y. Hong·S. Horvat·B. Huang·H. Z. Huang·S. L. Huang·T. Huang
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Abstract

We report the first measurement of the inclusive jet and the dijet longitudinal double-spin asymmetries, $A_{LL}$, at midrapidity in polarized $pp$ collisions at a center-of-mass energy $\sqrt{s} = 510$ GeV. The inclusive jet $A_{LL}$ measurement is sensitive to the gluon helicity distribution down to a gluon momentum fraction of $x\approx 0.015$, while the dijet measurements, separated into four jet-pair topologies, provide constraints on the $x$ dependence of the gluon polarization. Both results are consistent with previous measurements made at $\sqrt{s}= 200$ GeV in the overlapping kinematic region, $x > 0.05$, and show good agreement with predictions from recent next-to-leading order global analyses.

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STAR Collaboration, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, F. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. Barish, A. J. Bassill, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. Bryslawskyj, I. Bunzarov, J. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, S. Chattopadhyay, J. H. Chen, X. Chen, J. Cheng, M. Cherney, W. Christie, H. J. Crawford, M. Csanád, S. Das, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, L. Didenko, C. Dilks, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, R. Esha, S. Esumi, O. Evdokimov, J. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorisin, Y. Feng, P. Filip, E. Finch, Y. Fisyak, L. Fulek, C. A. Gagliardi, T. Galatyuk, F. Geurts, A. Gibson, K. Gopal, D. Grosnick, A. Gupta, W. Guryn, A. I. Hamad, A. Hamed, J. W. Harris, L. He, S. Heppelmann, N. Herrmann, L. Holub, Y. Hong, S. Horvat, B. Huang, H. Z. Huang, S. L. Huang, T. Huang. 2019-06-06. Longitudinal double-spin asymmetry for inclusive jet and dijet production in $pp$ collisions at $\sqrt{s} = 510$ GeV. https://doi.org/10.1103/physrevd.100.052005

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