冷核物质辐射低动量双电子的首次测量
核实验
2012-09-26 v2 高能物理 - 实验
摘要
我们展示了在GSI的HADES装置上测量的3.5 GeV动能束流下质子诱导反应在Nb靶上的双电子发射数据。这些数据是首次在预期有强介质效应的运动学区域内，对质子诱导的冷核物质双电子辐射进行的高统计量测量。结合2%的良好质量分辨率，这是首次对矢量介子谱函数变化的测量敏感，正如模型对静止或小相对动量强子所预测的那样。将e+e-不变质量谱与基本p+p数据比较，我们观察到对于e+e-动量Pee < 0.8 GeV/c，谱形有强烈修改，我们将其归因于额外的类ρ贡献和ω产额的减少。这些相反的趋势被初步解释为ρ介子与重子共振的强耦合以及ω介子的吸收，这是矢量介子介质内修正的两个方面。
引用
@article{arxiv.1205.1918,
title = {First measurement of low momentum dielectrons radiated off cold nuclear matter},
author = {G. Agakishiev and A. Balanda and D. Belver and A. Belyaev and J. C. Berger-Chen and A. Blanco and M. Böhmer and J. L. Boyard and P. Cabanelas and S. Chernenko and A. Dybczak and E. Epple and L. Fabbietti and O. Fateev and P. Finocchiaro and P. Fonte and J. Friese and I. Fröhlich and T. Galatyuk and J. A. Garzón and R. Gernhäuser and K. Göbel and M. Golubeva and D. González-Díaz and F. Guber and M. Gumberidze and T. Heinz and T. Hennino and R. Holzmann and A. Ierusalimov and I. Iori and A. Ivashkin and M. Jurkovic and B. Kämpfer and T. Karavicheva and I. Koenig and W. Koenig and B. W. Kolb and G. Kornakov and R. Kotte and A. Krása and F. Krizek and R. Krücken and H. Kuc and W. Kühn and A. Kugler and A. Kurepin and V. Ladygin and R. Lalik and S. Lang and K. Lapidus and A. Lebedev and T. Liu and L. Lopes and M. Lorenz and L. Maier and A. Mangiarotti and J. Markert and V. Metag and B. Michalska and J. Michel and D. Mishra and C. Müntz and L. Naumann and Y. C. Pachmayer and M. Palka and Y. Parpottas and V. Pechenov and O. Pechenova and J. Pietraszko and W. Przygoda and B. Ramstein and A. Reshetin and A. Rustamov and A. Sadovsky and P. Salabura and A. Schmah and E. Schwab and J. Siebenson and Yu. G. Sobolev and S. Spataro and B. Spruck and H. Ströbele and J. Stroth and C. Sturm and A. Tarantola and K. Teilab and P. Tlusty and M. Traxler and R. Trebacz and H. Tsertos and T. Vasiliev and V. Wagner and M. Weber and C. Wendisch and J. Wüstenfeld and S. Yurevich and Y. Zanevsky},
journal= {arXiv preprint arXiv:1205.1918},
year = {2012}
}