Modified structure of protons and neutrons in correlated pairs
Modified structure of protons and neutrons in correlated pairs
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DOI：
10.1038/s41586-019-0925-9
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发表时间：
2019-02
期刊：
影响因子：
64.8
通讯作者：
B. M. A. O. S. E. M. L. B. S. M. A. H. J. I. L. M. M. Schmookler Duer Schmidt Hen Gilad Piasetzky Strikm-B.-M.-A.-O.-S.-E.-M.-L.-B.-S.-M.-A.-H.-J.-I.-L.-M.-2080539512;B. Schmookler;M. Duer;A. Schmidt
中科院分区：
文献类型：
--
作者：
B. M. A. O. S. E. M. L. B. S. M. A. H. J. I. L. M. M. Schmookler Duer Schmidt Hen Gilad Piasetzky Strikm-B.-M.-A.-O.-S.-E.-M.-L.-B.-S.-M.-A.-H.-J.-I.-L.-M.-2080539512;B. Schmookler;M. Duer;A. Schmidt
原子核由质子和中子（核子）组成，而中子本身又由夸克和胶子组成。理解束缚在原子核中的核子的夸克-胶子结构如何被周围的核子改变是一个突出的挑战。虽然这种改变的证据，被称为EMC效应，在35年前首次观察到，但仍然没有普遍接受的原因解释。最近的观测表明，EMC效应与原子核中的近距离短程关联（SRC）核子对有关。在这里，我们报告的第一个同时，高精度，测量的EMC效应和SRC丰度。我们表明，EMC数据可以解释的中子-质子（NP）SRC对的核子结构的普遍修改，并提出了第一个数据驱动的提取这个普遍的修改功能。这意味着，在中子比质子多得多的重核中，每个质子比每个中子更有可能属于SRC对，因此其夸克结构发生扭曲。
The atomic nucleus is made of protons and neutrons (nucleons), that are themselves composed of quarks and gluons. Understanding how the quark-gluon structure of a nucleon bound in an atomic nucleus is modified by the surrounding nucleons is an outstanding challenge. Although evidence for such modification, known as the EMC effect, was first observed over 35 years ago, there is still no generally accepted explanation of its cause. Recent observations suggest that the EMC effect is related to close-proximity Short Range Correlated (SRC) nucleon pairs in nuclei. Here we report the first simultaneous, high-precision, measurements of the EMC effect and SRC abundances. We show that the EMC data can be explained by a universal modification of the structure of nucleons in neutron-proton (np) SRC pairs and present the first data-driven extraction of this universal modification function. This implies that, in heavier nuclei with many more neutrons than protons, each proton is more likely than each neutron to belong to an SRC pair and hence to have its quark structure distorted.