Measurement of eta_c(1S), eta_c(2S) and non-resonant eta' pi+ pi- production via two-photon collisions
The Belle Collaboration, Q. N. Xu, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Baki… 展开作者
The Belle Collaboration, Q. N. Xu, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, V. Bansal, E. Barberio, P. Behera, M. Berger, V. Bhardwaj, B. Bhuyan, J. Biswal, A. Bondar, A. Bozek, M. Bračko, D. Červenkov, A. Chen, B. G. Cheon, K. Chilikin, K. Cho, S. -K. Choi, Y. Choi, D. Cinabro, S. Cunliffe, T. Czank, N. Dash, S. Di Carlo, Z. Doležal, Z. Drásal, S. Eidelman, D. Epifanov, J. E. Fast, T. Ferber, B. G. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Garmash, M. Gelb, P. Goldenzweig, Y. Guan, E. Guido, J. Haba, K. Hayasaka, H. Hayashii, M. T. Hedges, W. -S. Hou, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, M. Iwasaki, Y. Iwasaki, I. Jaegle, H. B. Jeon, Y. Jin, K. K. Joo, T. Julius, A. B. Kaliyar, K. H. Kang, G. Karyan, T. Kawasaki, H. Kichimi, C. Kiesling, D. Y. Kim, H. J. Kim, J. B. Kim, P. Kodyš, S. Korpar, D. Kotchetkov, P. Križan, R. Kroeger, P. Krokovny, R. Kulasiri, Y. -J. Kwon, I. S. Lee, S. C. Lee, L. K. Li, Y. Li, L. Li Gioi, J. Libby, D. Liventsev, M. Lubej, T. Luo, M. Masuda, T. Matsuda, D. Matvienko, M. Merola, K. Miyabayashi, H. Miyata, R. Mizuk, H. K. Moon, T. Mori, R. Mussa, T. Nanut, K. J. Nath, Z. Natkaniec, M. Nayak, N. K. Nisar, S. Nishida, S. Okuno, H. Ono, Y. Onuki, P. Pakhlov, G. Pakhlova, B. Pal, H. Park, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, V. Popov, M. Ritter, A. Rostomyan, G. Russo, Y. Sakai, M. Salehi, S. Sandilya, T. Sanuki, V. Savinov, O. Schneider, G. Schnell, C. Schwanda, Y. Seino, K. Senyo, O. Seon, M. E. Sevior, V. Shebalin, C. P. Shen, T. -A. Shibata, N. Shimizu, J. -G. Shiu, A. Sokolov, E. Solovieva, M. Starič, J. F. Strube, T. Sumiyoshi, M. Takizawa, U. Tamponi, K. Tanida, F. Tenchini, M. Uchida, S. Uehara, T. Uglov, Y. Unno, S. Uno, P. Urquijo, C. Van Hulse, G. Varner, A. Vinokurova, V. Vorobyev, A. Vossen, B. Wang, C. H. Wang, M. -Z. Wang, P. Wang, X. L. Wang, M. Watanabe, Y. Watanabe, E. Widmann, E. Won, H. Ye, C. Z. Yuan, Y. Yusa, S. Zakharov, C. C. Zhang, Z. P. Zhang, V. Zhilich, V. Zhukova, V. Zhulanov, A. Zupanc
We report the measurement of gamma gamma to eta_c(1S), eta_c(2S) to eta' pi+ pi- with eta' decays to gamma rho and eta pi+ pi- using 941 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The eta_c(1S) mass and width are measured to be M = [2984.6 \pm 0.7 (stat.) \pm 2.2 (syst.)] MeV/c^{2} and Γ= [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)] MeV, respectively. First observation of eta_c(2S) to eta' pi+ pi- with a significance of 5.5sigma including systematic error is obtained, and the eta_c(2S) mass is measured to be M = [3635.1 \pm 3.7~(stat.) \pm 2.9~(syst.)] MeV/c^{2}. The products of the two-photon decay width and branching fraction (B) of decays to eta'pi+ pi- are determined to be Γ_{gamma gamma}B = [65.4 \pm 2.6~(stat.) \pm 6.9~(syst.)] eV for eta_c(1S) and [5.6^{+1.2}_{-1.1}~(stat.) \pm 1.1~(syst.)] eV for eta_c(2S). A new decay mode for the eta_c(1S) to eta'f_0(2080) with f_0(2080) to pi+ pi- is observed with a statistical significance of 20sigma. The f_0(2080) mass and width are determined to be M = [2083^{+63}_{-66}~(stat.) \pm 32~(syst.)] MeV/c^{2} and Γ= [178^{+60}_{-178}~(stat.) \pm 55~(syst.)] MeV. The cross sections for gamma gamma to eta' pi+ pi- and eta' f_{2} (1270) are measured for the first time.
英文摘要：
We report the measurement of gamma gamma to eta_c(1S), eta_c(2S) to eta' pi+ pi- with eta' decays to gamma rho and eta pi+ pi- using 941 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The eta_c(1S) mass and width are measured to be M = [2984.6\pm0.7 (stat.)\pm2.2 (syst.)] MeV/c^{2} and Γ= [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)] MeV, respectively. First observation of eta_c(2S) to eta' pi+ pi- with a significance of 5.5sigma including systematic error is obtained, and the eta_c(2S) mass is measured to be M = [3635.1\pm3.7~(stat.)\pm2.9~(syst.)] MeV/c^{2}. The products of the two-photon decay width and branching fraction (B) of decays to eta'pi+ pi- are determined to be Γ_{gamma gamma}B = [65.4\pm2.6~(stat.)\pm6.9~(syst.)] eV for eta_c(1S) and [5.6^{+1.2}_{-1.1}~(stat.)\pm1.1~(syst.)] eV for eta_c(2S). A new decay mode for the eta_c(1S) to eta'f_0(2080) with f_0(2080) to pi+ pi- is observed with a statistical significance of 20sigma. The f_0(2080) mass and width are determined to be M = [2083^{+63}_{-66}~(stat.)\pm 32~(syst.)] MeV/c^{2} and Γ= [178^{+60}_{-178}~(stat.) \pm 55~(syst.)] MeV. The cross sections for gamma gamma to eta' pi+ pi- and eta'f_{2}(1270) are measured for the first time.
Rapidity gap cross sections measured with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV
利用积分亮度为7.1微仓的最小偏差数据样本，研究了sqrt（s）= 7 TeV质子-质子碰撞中赝快度能隙的分布。截面是用Δ eta F差分测量的，在eta = +/- 4.9时，扩展到ATLAS灵敏度极限的伪快度区域中较大的一个，其中在横向动量阈值p_T Cut以上没有产生终态粒子。对于200 < p_T切割< 800 MeV，测量跨越区域0 <Δ eta F < 8。在小Δ eta F，数据测试强子化模型的可靠性，在描述速度和横向动量波动的最终状态粒子生产。在更大的间隙尺寸的测量是由来自单衍射解离过程（pp -> Xp）的贡献占主导地位，由双解离（pp -> XY）增强，其中两个解离系统中较轻的不变质量满足M_Y <~ 7 GeV。得到的截面为d sigma / d Delta eta F ~ 1 mb，其中Delta eta F >~ 3。大快度间隙的数据被用来约束的软衍射的三重Regge模型适当的坡密子截距的值。集成在所有间隙尺寸的截面与其他LHC非弹性截面测量进行了比较。
Transverse Single Spin Asymmetries and Cross-Sections for Forward pi0 and eta Mesons at Large Feynman-x in sqrt(s)=200 GeV polarized p+p Collisions at STAR
Transverse Single-Spin Asymmetries of Midrapidity Direct Photons, Neutral Pions, and Eta Mesons in 200 GeV Polarized Proton-Proton Collisions at PHENIX
