Coherent diffractive photoproduction of $ρ^{0}$ mesons on gold nuclei at RHIC

Journal Article

The STAR Collaboration reports on the photoproduction of $\pi^+\pi^-$ pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly-real photon emitted by one ion scatters from the other ion. We fit the $\pi^+\pi^-$ invariant mass spectrum with a combination of $\rho$ and $\omega$ resonances and a direct $\pi^+\pi^-$ continuum. This is the first observation of the $\omega$ in ultra-peripheral collisions, and the first measurement of $\rho-\omega$ interference at energies where photoproduction is dominated by Pomeron exchange. The $\omega$ amplitude is consistent with the measured $\gamma p\rightarrow \omega p$ cross section, a classical Glauber calculation and the $\omega\rightarrow\pi^+\pi^-$ branching ratio. The $\omega$ phase angle is similar to that observed at much lower energies, showing that the $\rho-\omega$ phase difference does not depend significantly on photon energy. The $\rho^0$ differential cross section $d\sigma/dt$ exhibits a clear diffraction pattern, compatible with scattering from a gold nucleus, with 2 minima visible. The positions of the diffractive minima agree better with the predictions of a quantum Glauber calculation that does not include nuclear shadowing than with a calculation that does include shadowing.

Full Text

Duke Authors

Cited Authors

  • Collaboration, STAR; Adamczyk, L; Adkins, JK; Agakishiev, G; Aggarwal, MM; Ahammed, Z; Ajitanand, NN; Alekseev, I; Anderson, DM; Aoyama, R; Aparin, A; Arkhipkin, D; Aschenauer, EC; Ashraf, MU; Attri, A; Averichev, GS; Bai, X; Bairathi, V; Behera, A; Bellwied, R; Bhasin, A; Bhati, AK; Bhattarai, P; Bielcik, J; Bielcikova, J; Bland, LC; Bordyuzhin, IG; Bouchet, J; Brandenburg, JD; Brandin, AV; Brown, D; Bunzarov, I; Butterworth, J; Caines, H; Sánchez, MCDLB; Campbell, JM; Cebra, D; Chakaberia, I; Chaloupka, P; Chang, Z; Chankova-Bunzarova, N; Chatterjee, A; Chattopadhyay, S; Chen, X; Chen, JH; Cheng, J; Cherney, M; Christie, W; Contin, G; Crawford, HJ; Das, S; Silva, LCD; Debbe, RR; Dedovich, TG; Deng, J; Derevschikov, AA; Didenko, L; Dilks, C; Dong, X; Drachenberg, JL; Draper, JE; Dunkelberger, LE; Dunlop, JC; Efimov, LG; Elsey, N; Engelage, J; Eppley, G; Esha, R; Esumi, S; Evdokimov, O; Ewigleben, J; Eyser, O; Fatemi, R; Fazio, S; Federic, P; Federicova, P; Fedorisin, J; Feng, Z; Filip, P; Finch, E; Fisyak, Y; Flores, CE; Fujita, J; Fulek, L; Gagliardi, CA; Garand, D; Geurts, F; Gibson, A; Girard, M; Grosnick, D; Gunarathne, DS; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Hamad, AI; Hamed, A; Harlenderova, A; Harris, JW; He, L; Heppelmann, S; Hirsch, A; Hoffmann, GW; Horvat, S; Huang, B; Huang, T; Huang, HZ; Huang, X; Humanic, TJ; Huo, P; Igo, G; Jacobs, WW; Jentsch, A; Jia, J; Jiang, K; Jowzaee, S; Judd, EG; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, HW; Keane, D; Kechechyan, A; Khan, Z; Kikoła, DP; Kisel, I; Kisiel, A; Klein, SR; Kochenda, L; Kocmanek, M; Kollegger, T; Kosarzewski, LK; Kraishan, AF; Kravtsov, P; Krueger, K; Kulathunga, N; Kumar, L; Kvapil, J; Kwasizur, JH; Lacey, R; Landgraf, JM; Landry, KD; Lauret, J; Lebedev, A; Lednicky, R; Lee, JH; Li, W; Li, X; Li, C; Li, Y; Lidrych, J; Lin, T; Lisa, MA; Liu, Y; Liu, F; Liu, H; Liu, P; Ljubicic, T; Llope, WJ; Lomnitz, M; Longacre, RS; Luo, S; Luo, X; Ma, GL; Ma, YG; Ma, L; Ma, R; Magdy, N; Majka, R; Mallick, D; Margetis, S; Markert, C; Matis, HS; Meehan, K; Mei, JC; Miller, ZW; Minaev, NG; Mioduszewski, S; Mishra, D; Mizuno, S; Mohanty, B; Mondal, MM; Morozov, DA; Mustafa, MK; Nasim, M; Nayak, TK; Nelson, JM; Nie, M; Nigmatkulov, G; Niida, T; Nogach, LV; Nonaka, T; Nurushev, SB; Odyniec, G; Ogawa, A; Oh, K; Okorokov, VA; Jr, DO; Page, BS; Pak, R; Pandit, Y; Panebratsev, Y; Pawlik, B; Pei, H; Perkins, C; Pile, P; Pluta, J; Poniatowska, K; Porter, J; Posik, M; Poskanzer, AM; Pruthi, NK; Przybycien, M; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Ray, RL; Reed, R; Rehbein, MJ; Ritter, HG; Roberts, JB; Rogachevskiy, OV; Romero, JL; Roth, JD; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, NR; Sahu, PK; Salur, S; Sandweiss, J; Saur, M; Schambach, J; Schmah, AM; Schmidke, WB; Schmitz, N; Schweid, BR; Seger, J; Sergeeva, M; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, PV; Shao, M; Sharma, A; Sharma, MK; Shen, WQ; Shi, Z; Shi, SS; Shou, QY; Sichtermann, EP; Sikora, R; Simko, M; Singha, S; Skoby, MJ; Smirnov, N; Smirnov, D; Solyst, W; Song, L; Sorensen, P; Spinka, HM; Srivastava, B; Stanislaus, TDS; Strikhanov, M; Stringfellow, B; Sugiura, T; Sumbera, M; Summa, B; Sun, Y; Sun, XM; Sun, X; Surrow, B; Svirida, DN; Tang, AH; Tang, Z; Taranenko, A; Tarnowsky, T; Tawfik, A; Thäder, J; Thomas, JH; Timmins, AR; Tlusty, D; Todoroki, T; Tokarev, M; Trentalange, S; Tribble, RE; Tribedy, P; Tripathy, SK; Trzeciak, BA; Tsai, OD; Ullrich, T; Underwood, DG; Upsal, I; Buren, GV; Nieuwenhuizen, GV; Vasiliev, AN; Videbæk, F; Vokal, S; Voloshin, SA; Vossen, A; Wang, G; Wang, Y; Wang, F; Webb, JC; Webb, G; Wen, L; Westfall, GD; Wieman, H; Wissink, SW; Witt, R; Wu, Y; Xiao, ZG; Xie, W; Xie, G; Xu, J; Xu, N; Xu, QH; Xu, YF; Xu, Z; Yang, Y; Yang, Q; Yang, C; Yang, S; Ye, Z; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zbroszczyk, H; Zha, W; Zhang, Z; Zhang, XP; Zhang, JB; Zhang, S; Zhang, J; Zhang, Y; Zhao, J; Zhong, C; Zhou, L; Zhou, C; Zhu, X; Zhu, Z; Zyzak, M

Digital Object Identifier (DOI)

  • 10.1103/PhysRevC.96.054904