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arXiv · 1404.7461

Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central $d$$+$Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV

Abstract

We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central $d$$+$Au and minimum bias $p$$+$$p$ collisions at $\sqrt{s_{_{NN}}}=200$ GeV. The charged hadron is measured at midrapidity $|\eta|<0.35$, and the energy is measured at large rapidity ($-3.7<\eta<-3.1$, Au-going direction). An enhanced near-side angular correlation across $|\Delta\eta| >$ 2.75 is observed in $d$$+$Au collisions. Using the event plane method applied to the Au-going energy distribution, we extract the anisotropy strength $v_2$ for inclusive charged hadrons at midrapidity up to $p_T=4.5$ GeV/$c$. We also present the measurement of $v_2$ for identified $\pi^{\pm}$ and (anti)protons in central $d$$+$Au collisions, and observe a mass-ordering pattern similar to that seen in heavy ion collisions. These results are compared with viscous hydrodynamic calculations and measurements from $p$$+$Pb at $\sqrt{s_{_{NN}}}=5.02$ TeV. The magnitude of the mass-ordering in $d$$+$Au is found to be smaller than that in $p$$+$Pb collisions, which may indicate smaller radial flow in lower energy $d$$+$Au collisions.

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A. Adare, C. Aidala, N. N. Ajitanand, Y. Akiba, R. Akimoto, H. Al-Bataineh, H. Al-Ta'ani, J. Alexander, K. R. Andrews, A. Angerami, K. Aoki, N. Apadula, E. Appelt, Y. Aramaki, R. Armendariz, E. C. Aschenauer, E. T. Atomssa, R. Averbeck, T. C. Awes, B. Azmoun, V. Babintsev, M. Bai, G. Baksay, L. Baksay, B. Bannier, K. N. Barish, B. Bassalleck, A. T. Basye, S. Bathe, V. Baublis, C. Baumann, A. Bazilevsky, S. Belikov, R. Belmont, J. Ben-Benjamin, R. Bennett, J. H. Bhom, D. S. Blau, J. S. Bok, K. Boyle, M. L. Brooks, D. Broxmeyer, H. Buesching, V. Bumazhnov, G. Bunce, S. Butsyk, S. Campbell, A. Caringi, P. Castera, C. -H. Chen, C. Y. Chi, M. Chiu, I. J. Choi, J. B. Choi, R. K. Choudhury, P. Christiansen, T. Chujo, P. Chung, O. Chvala, V. Cianciolo, Z. Citron, B. A. Cole, Z. Conesa del Valle, M. Connors, M. Csanád, T. Csörgő, T. Dahms, S. Dairaku, I. Danchev, K. Das, A. Datta, G. David, M. K. Dayananda, A. Denisov, A. Deshpande, E. J. Desmond, K. V. Dharmawardane, O. Dietzsch, A. Dion, M. Donadelli, O. Drapier, A. Drees, K. A. Drees, J. M. Durham, A. Durum, D. Dutta, L. D'Orazio, S. Edwards, Y. V. Efremenko, F. Ellinghaus, T. Engelmore, A. Enokizono, H. En'yo, S. Esumi, B. Fadem, D. E. Fields, M. Finger, M. Finger, Jr., F. Fleuret, S. L. Fokin. 2014-04-29. Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central $d$$+$Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV. https://doi.org/10.1103/physrevlett.114.192301

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