arXiv · 1606.01815
Measurements of double-helicity asymmetries in inclusive $J/ψ$ production in longitudinally polarized $p+p$ collisions at $\sqrt{s}=510$ GeV
Abstract
We report the double helicity asymmetry, $A_{LL}^{J/ψ}$, in inclusive $J/ψ$ production at forward rapidity as a function of transverse momentum $p_T$ and rapidity $|y|$. The data analyzed were taken during $\sqrt{s}=510$ GeV longitudinally polarized $p$$+$$p$ collisions at the Relativistic Heavy Ion Collider (RHIC) in the 2013 run using the PHENIX detector. At this collision energy, $J/ψ$ particles are predominantly produced through gluon-gluon scatterings, thus $A_{LL}^{J/ψ}$ is sensitive to the gluon polarization inside the proton. We measured $A_{LL}^{J/ψ}$ by detecting the decay daughter muon pairs $μ^+ μ^-$ within the PHENIX muon spectrometers in the rapidity range $1.2<|y|<2.2$. In this kinematic range, we measured the $A_{LL}^{J/ψ}$ to be $0.012 \pm 0.010$~(stat)~$\pm$~$0.003$(syst). The $A_{LL}^{J/ψ}$ can be expressed to be proportional to the product of the gluon polarization distributions at two distinct ranges of Bjorken $x$: one at moderate range $x \approx 0.05$ where recent RHIC data of jet and $π^0$ double helicity spin asymmetries have shown evidence for significant gluon polarization, and the other one covering the poorly known small-$x$ region $x \approx 2\times 10^{-3}$. Thus our new results could be used to further constrain the gluon polarization for $x< 0.05$.
Explore related subjects
Keep this discovery
Explore connections, maps & timelines
A. Adare, C. Aidala, N. N. Ajitanand, Y. Akiba, R. Akimoto, M. Alfred, N. Apadula, Y. Aramaki, H. Asano, E. T. Atomssa, T. C. Awes, B. Azmoun, V. Babintsev, M. Bai, N. S. Bandara, B. Bannier, K. N. Barish, S. Bathe, A. Bazilevsky, M. Beaumier, S. Beckman, R. Belmont, A. Berdnikov, Y. Berdnikov, D. Black, D. S. Blau, J. S. Bok, K. Boyle, M. L. Brooks, J. Bryslawskyj, H. Buesching, V. Bumazhnov, S. Campbell, C. -H. Chen, C. Y. Chi, M. Chiu, I. J. Choi, J. B. Choi, T. Chujo, Z. Citron, M. Csanád, T. Csörgő, T. W. Danley, A. Datta, M. S. Daugherity, G. David, K. DeBlasio, K. Dehmelt, A. Denisov, A. Deshpande, E. J. Desmond, L. Ding, A. Dion, P. B. Diss, J. H. Do, A. Drees, K. A. Drees, J. M. Durham, A. Durum, A. Enokizono, H. En'yo, S. Esumi, B. Fadem, N. Feege, D. E. Fields, M. Finger, M. Finger, Jr., S. L. Fokin, J. E. Frantz, A. Franz, A. D. Frawley, C. Gal, P. Gallus, P. Garg, H. Ge, F. Giordano, A. Glenn, Y. Goto, N. Grau, S. V. Greene, M. Grosse Perdekamp, Y. Gu, T. Gunji, H. Guragain, T. Hachiya, J. S. Haggerty, K. I. Hahn, H. Hamagaki, H. F. Hamilton, S. Y. Han, J. Hanks, S. Hasegawa, T. O. S. Haseler, K. Hashimoto, X. He, T. K. Hemmick, J. C. Hill, R. S. Hollis, K. Homma, B. Hong. 2017-01-04. Measurements of double-helicity asymmetries in inclusive $J/ψ$ production in longitudinally polarized $p+p$ collisions at $\sqrt{s}=510$ GeV. https://doi.org/10.1103/physrevd.94.112008
Cite the original work for its findings. Save a collection to share your selection of sources.