Modification of Heavy Quarkonia Production in Nuclear Collisions

我们现在知道，大多数可见物质是由核子(质子和中子)组成的，而核子又由更基本的成分组成：夸克和胶子。一种名为夸克-胶子-等离子体(QGP)的新物质形式可以通过非常高能量的核子碰撞而产生。这个QGP被认为复制了宇宙大爆炸后百万分之一秒的早期宇宙的情况。该奖项支持在质子与质子、质子与金核以及金核与金核的碰撞中，由重夸克产生的夸克-反夸克对(介子，称为查莫尼和底夸克)的研究。这将进一步加深对重夸克介子与QGP相互作用的理解，最终目的是更好地理解支配强相互作用QGP演化的机制，QGP是有史以来产生的最强耦合的液体。理解QGP对于我们理解夸克和胶子之间的相互作用是至关重要的。这项研究将主要由研究生进行。他们将在首席研究员的指导下，根据研究结果撰写博士论文。本科生也将大量参与研究，为他们提供很好的物理研究方法和工具的介绍。这项研究将使用相对论重离子对撞机(RHIC)顶端碰撞根能量(SNN)=200GeV的碰撞数据进行，并将重点放在两个领域。第一个领域是利用现有的数据研究p+Au碰撞中的碳素产生--由RHIC的PHENIX实验从p+Au(和3He+Au)碰撞中记录下来的。这项研究的目的是为了更好地了解在核目标中发生的碳素生产被修改的机制。这种修饰是由胶子在原子核内相互作用的方式决定的，这一点目前仍未被完全理解。此外，测量靶中碳素生成的变化也为QGP在Au+Au碰撞中测量碳素的变化提供了基线。第二个领域是利用RHIC的sphenix实验未来的测量结果来研究p+Au和Au+Au碰撞中的底钼生产。这将进一步加深对重离子碰撞中产生的下位素与QGP相互作用的理解。由于Charmonium和Bottomonium介子具有非常不同的性质，它们提供了关于QGP中相互作用的补充信息。拟议的研究包括对跟踪技术和软件的开发做出重大贡献，这些技术和软件必须在目前正在建设的sPHENIX探测器于2022年投入使用之前到位。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

We now know that most visible matter is composed of nucleons (protons and neutrons), which in turn are made up of more elementary constituents: quarks and gluons. A new form of matter called the quark-gluon-plasma (QGP) can be created through very energetic collisions of nucleons. This QGP is thought to replicate the conditions in the early Universe a millionth of a second after the Big Bang. This award supports the study of the production of quark-antiquark pairs (mesons, called charmonium and bottomonium) made from heavy quarks in collisions of protons with protons, of protons with gold nuclei, and of gold nuclei with gold nuclei. This will further the understanding of the interactions of heavy quark mesons with the QGP, with the ultimate goal of better understanding the mechanisms that govern the evolution of the strongly interacting QGP, the most strongly coupled liquid ever created. Understanding the QGP is critical to our understanding of the interactions between quarks and gluons. The research will be conducted in large part by graduate students. They will write doctoral dissertations based on the results, under the mentorship of the principal investigator. There will also be significant involvement of undergraduate students in the research, providing them with a good introduction to physics research methods and tools. The research will be conducted using data from collisions at the top Relativistic Heavy Ion Collider (RHIC) collision energy of root(sNN) = 200 GeV, and will focus in two areas. The first area is the study of charmonium production in p+Au collisions using existing data - recorded by the PHENIX experiment at RHIC from p+Au (and 3He+Au) collisions. This research is aimed at better understanding the mechanisms by which charmonium production is modified when it takes place in a nuclear target. That modification is governed by the way that gluons interact inside a nucleus, which is still imperfectly understood. Also, measuring the modification of charmonium production in a target provides a baseline for measurements of charmonium modification by the QGP in Au+Au collisions. The second area is the study of bottomonium production in p+Au and Au+Au collisions using future measurements by the sPHENIX experiment at RHIC. This will further the understanding of bottomonium interactions with the QGP produced in heavy ion collisions. Because charmonium and bottomonium mesons have very different properties, they provide complementary information about interactions within the QGP. The proposed research includes a significant contribution to the development of tracking techniques and software that must be in place before the sPHENIX detector, currently under construction, is commissioned in 2022.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.