Transverse single-spin asymmetries of midrapidity <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mi>π</mml:mi><mml:mn>0</mml:mn></mml:msup></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>η</mml:mi></mml:math> mesons in polarized <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mo>+</mml:mo><mml:mi>p</mml:mi></mml:math> collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi></mml:math>
U. Acharya, C. Aidala, Y. Akiba, M. Alfred, V. Andrieux, N. Apadula, H. Asano, B. Azmoun, V. Babintsev, N. S. Bandara, K. N. Barish, S. Bathe, A. Bazilevsky, M. Beaumier, R. Belmont, A. Berdnikov, Y. Berdnikov, L. Bichon, B. Blankenship, D. Blau, J. S. Bok, V. Borisov, M. L. Brooks, J. Bryslawskyj, V. Bumazhnov, S. Campbell, V. Canoa Roman, R. Cervantes, C. Y. Chi, M. Chiu, I. J. Choi, J. B. Choi, Z. H. Citron, M. Connors, R. Corliss, N. Cronin, M. Csanád, T. Csörgő, T. W. Danley, M. Daugherity, G. David, K. DeBlasio, K. Dehmelt, A. Denisov, A. Deshpande, E. J. Desmond, A. Dion, D. Dixit, J. H., A. Drees, K. A. Drees, J. M. Durham, A. Durum, A. Enokizono, H. En’yo, R. Esha, S. Esumi, B. Fadem, W. Fan, N. Feege, D. E. Fields, M. Finger, М. Фингер, D. Firak, D. S. Fitzgerald, S. Fokin, J. E. Frantz, A. Franz, A. D. Frawley, Y. Fukuda, C. Gal, P. Gallus, P. Garg, H. Ge, M. Giles, F. Giordano, Y. Goto, N. Grau, S. V. Greene, M. Große Perdekamp, T. Gunji, H. Guragain, T. Hachiya, J. S. Haggerty, K. I. Hahn, H. Hamagaki, H. F. Hamilton, Seyoung Han, J. Hanks, S. Hasegawa, T. O. S. Haseler, X. He, T. K. Hemmick, J. C. Hill, K. K. Hill, A. Hodges, R. S. Hollis, K. Homma, B. Hong, T. Hoshino
Abstract
We present a measurement of the transverse single-spin asymmetry for ${\ensuremath{\pi}}^{0}$ and $\ensuremath{\eta}$ mesons in ${p}^{\ensuremath{\uparrow}}+p$ collisions in the pseudorapidity range $|\ensuremath{\eta}|<0.35$ and at a center-of-mass energy of 200 GeV with the PHENIX detector at the Relativistic Heavy Ion Collider. In comparison with previous measurements in this kinematic region, these results have factor-of-3-smaller uncertainties. As hadrons, ${\ensuremath{\pi}}^{0}$ and $\ensuremath{\eta}$ mesons are sensitive to both initial- and final-state nonperturbative effects for a mix of parton flavors. Comparisons of the differences in their transverse single-spin asymmetries have the potential to disentangle the possible effects of strangeness, isospin, or mass. These results can constrain the twist-3 trigluon collinear correlation function as well as the gluon Sivers function.