CAREER: Studies of Heavy Quarkonium Production in Relativistic Heavy-Ion Collisions at UC Davis.

职业：相对论重离子碰撞中重夸克偶素产生的研究摘要：在对自然界基本相互作用的研究中，强核相互作用是最有趣的研究之一。 这种力作用于夸克和胶子，它们是构成质子和中子的基本粒子，因此也是我们周围所有物质的基本组成部分。强相互作用的一个关键特性是夸克和胶子永远不会孤立地出现，这种现象称为“禁闭”。当核物质被加热到极端条件时，这种行为就会发生变化。 计算预测，正常的核物质在一定温度下存在。在这个温度以上，有一个过渡到核子溶解的阶段，使得它们内部的夸克和胶子被释放出来。 这些“解除限制”的夸克和胶子因此形成了一种新的核物质状态，被称为夸克-胶子等离子体（QGP）。 在大爆炸后的几微秒，宇宙被认为已经越过了这个相界，随着温度的降低，从QGP凝聚成强子气体。 在实验方面，在实验室中制备QGP并研究其性质是高能重离子碰撞实验的主要目标。 这项研究的两个关键问题是：a）产生碰撞中产生的物质由退禁闭夸克和胶子组成的证据，以及B）确定产生的系统的温度高于交叉温度。 解决上述问题有几个途径，本提案只涉及其中一个途径。这是对由相对较重的夸克-反夸克对组成的粒子的研究，它们被强作用力束缚。这些态是有趣的，因为在QGP中，高温和解除束缚的轻夸克和胶子的存在改变了这些重夸克-反夸克态的光谱性质，使它们不再结合。当重离子碰撞形成QGP时，这些态的产生因此相对于没有形成QGP的质子+质子或氘核+核碰撞被抑制，从而提供了解除限制的签名。 由于这些夸克-反夸克粒子的基态和激发态在不同的温度下熔化，测量相对比值为实验学家提供了这种极热物质的温度计。 在这项提议中，主要研究者将测量重离子碰撞中最重的夸克-反夸克束缚态的产生。 调查将在最高能量的重离子碰撞加速器上进行：在布鲁克海文国家实验室（纽约长岛）的相对论重离子对撞机上使用星星探测器，在欧洲高能物理实验室（瑞士日内瓦欧洲核子研究中心）的大型强子对撞机上使用CMS探测器。 他将指导参加戴维斯REU项目的本科生。 他是科学促进奇卡诺人和美洲原住民协会（SACNAS）的成员。通过SACNAS，PI将重离子研究的兴奋传达给未来的拉丁裔科学家，在年度会议期间指导学生，参与学生海报的选择，并评判学生的演讲。 最后，他将为戴维斯的西班牙语浸入式学校塞萨尔查韦斯学校的理科学生开发物理演示和演示。

CAREER: Studies of Heavy Quarkonium Production in Relativistic Heavy-Ion Collisions at UC Davis.Abstract:In the study of the basic interactions of nature, one of the most intriguing is the strong nuclear interaction. This is the force which deals with quarks and gluons, which are the elementary particles that make up protons and neutrons, and are therefore the basic building blocks of all the matter we see around us. A key property of the strong interaction is that quarks and gluons are never seen in isolation, a phenomenon called "confinement". This behavior changes when nuclear matter is heated to extreme conditions. Calculations predict that normal nuclear matter exists up to a certain temperature. Above this temperature, there is a cross-over to a phase where nucleons dissolve such that their inner quarks and gluons are liberated. These "deconfined" quarks and gluons thus form a new state of nuclear matter, which has been called the Quark-Gluon Plasma (QGP). A few microseconds after the Big Bang, the universe is believed to have crossed this phase boundary, condensing from a QGP to a hadron gas as the temperature decreased. In the experimental front, producing the QGP in the laboratory and studying its properties is the main goal of experiments with heavy-ion collisions at high-energies. Two key issues in this search are a) producing evidence that the matter produced in the collisions consists of deconfined quarks and gluons, and b) determining that the temperature of the produced system is above the cross-over temperature. There are several avenues to attack the above issues, and in this proposal, one of them is addressed. This is the study of particles made of relatively heavy quark-antiquark pairs, which are bound by the strong force. These states are interesting because in a QGP, the high temperatures and the presence of deconfined lighter quarks and gluons modify the spectral properties of these heavy quark-antiquark states such that they no longer bind. When a heavy-ion collision forms a QGP, the production of these states is therefore suppressed relative to proton+proton or deuteron+nucleus collisions where no QGP is formed, providing a signature for deconfinement. Since the ground states and the excited states of these quark-antiquark particles melt at different temperatures, measuring the relative ratios provides experimentalists with a thermometer for this extremely hot matter. In this proposal, the Principal Investigator will measure the production of the heaviest available quark-antiquark bound states in heavy ion collisions. The investigations will be carried out at the highest energy accelerators for heavy ion collisions: with the STAR detector at the Relativistic Heavy-Ion Collider located in Brookhaven National Laboratory (Long Island, NY) and with the CMS detector at the Large Hadron Collider in the European Laboratory for High Energy Physics (CERN, Geneva, Switzerland).The PI will maintain an outreach program focusing on three components. He will mentor undergraduate students participating in the REU program at Davis. He is a member of the Society of the Advancement of Chicanos and Native Americans in Science (SACNAS). Through SACNAS, the PI communicates the excitement of heavy-ion research to future Latino scientists, mentors students during their annual conference, participates in the selection of student posters, and judges student presentations. Finally, he will develop physics presentations and demonstrations for the science students of the Cesar Chavez School, a Spanish-immersion school in Davis.