极端相对论核—核碰撞中的双轻子、光子和轻矢量介子产生

发布时间：2018-04-04 14:19

本文选题：双轻子　切入点：光子　出处：《云南大学》2016年博士论文

【摘要】：在极端相对论重离子碰撞中,微扰量子色动力学(perturbative Quantum Chromodynamics, pQCD)预言在碰撞中心区域物质能量密度可以足够高而形成夸克物质解禁相。在高能重离子碰撞中,碰撞中心区域能物质量密度很高使得物质离开强子相进入夸克物质解禁相(Glasma和夸克-胶子等离子体),然后夸克物质继续膨胀冷却回到强子相。当物质处于Glasma和热夸克-胶子等离子体相时,夸克物质中部分子之间相互作用产生的双轻子、光子和轻矢量介子(ρ、ω、φ)就会携带夸克物质的信息。本文研究相对论重离子对撞机(Relativistic Heavy Ion Collider, RHIC)和大型强子对撞机(Large Hadron Collider, LHC)能区相对论核-核碰撞中夸克物质的产生及其时空演化过程和双轻子、光子、轻矢量介子硬光生过程,以及色玻璃凝聚态(colour glass condensate, CGC)、Glasma、夸克-胶子等离子体(quark-gluon plasma, QGP)和热强子气体(hadronic gas, HG)中的双轻子、光子和轻矢量介子产生。在相对论核-核碰撞的早期,大转移动量双轻子、光子和轻矢量介子主要来源于初始部分子硬散射过程、硬光生过程和碎裂过程。部分子硬散射过程主要是夸克-反夸克湮灭、夸克-胶子康普顿散射和胶子-胶子聚变过程。硬光生过程包括弹性硬双光子过程、半弹性(直接和分解)硬光生过程和深度非弹性(直接和分解)硬光生过程。在直接硬光生过程中,入射原子核(原子核内的荷电部分子)发射的高能光子将会与另一个入射原子核内的部分子通过夸克-光子康普顿散射、胶子-光子聚合相互作用产生双轻子、光子和轻矢量介子。在分解硬光生过程中,入射原子核(原子核内的荷电部分子)发射的高能类强子光子会涨落出部分子,然后涨落出来的部分子与另一个入射原子核内的部分子通过夸克-反夸克湮灭、夸克-胶子康普顿散射和胶子-胶子聚合相互作用产生双轻子、光子和轻矢量介子。此外,在碎裂过程中,快喷注在碎裂成双轻子、光子和轻矢量介子之前,将会穿过核物质媒介而损失能量(喷注淬火效应),损失能量后的快喷注再碎裂成双轻子、光子和轻矢量介子。从数值结果可以看出,在大型强子对撞机(LHC)能区的p-p碰撞和Pb-Pb碰撞中,双轻子、光子和轻矢量介子硬光生过程、碎裂过程的贡献是显著的。然而,在色玻璃凝聚胶子饱和框架下,胶子密度在转移动量小于胶子饱和动量Qs时会出现饱和而形成色玻璃凝聚(CGC),然后处于色玻璃凝聚态的两个原子核相互碰撞就会形成高胶子密度的非平衡态物质Glasma。在极端相对论情况下,胶子饱和动量Qs将远大于量子色动力学禁闭标度AQCD从而使得跑动耦合常数αs(Qs)《1,因此可以利用KT-因子化来计算色玻璃凝聚中的双轻子、光子和轻矢量介子产生。在色玻璃凝聚胶子饱和区域,双轻子、光子和轻矢量介子主要来源于胶子-胶子聚合相互作用过程。从数值结果可以看出,在相对论重离子对撞机(RHIC)和大型强子对撞机(LHC)能区的p-p碰撞、Au-Au碰撞、p-Pb碰撞和Pb-Pb碰撞中,来自于色玻璃凝聚的低转移动量双轻子、低转移动量光子和低转移动量轻矢量介子的贡献是很重要的。此外,在色玻璃凝聚胶子饱和框架下,相对论核-核碰撞中心区域能量密度很高而可以形成高胶子密度Glasma态,此时Glasma还没有达到热平衡,而是处于以胶子为主导的胶子饱和态。在胶子饱和区域,胶子饱和动量Qs将远大于量子色动力学禁闭标度ΛQCD从而使得跑动耦合常数αs(Qs)1,此时就可以将Glasma看作为一个弱耦合系统并且可以用相对论动力学理论来描述。在Glasma中,低质量双轻子主要来源于夸克-反夸克湮灭过程,低转移动量热光子主要来源于夸克-反夸克湮灭、夸克-胶子康普顿散射和胶子-胶子聚合过程,而且由于Glasma是有胶子主导的,因此低转移动量热光子最主要的贡献是来自于胶子-胶子聚合过程。从数值结果可以看出,在相对论重离子对撞机(RHIC)和大型强子对撞机(LHC)能区,来自于Glasma的低不变质量双轻子和低转移动量光子的贡献是很显著的。接着,随着Glasma的膨胀,在固有时刻τth时Glasma将热化形成热夸克-胶子等离子体,在热夸克-胶子等离子体低质量双轻子主要来源于夸克-反夸克湮灭过程,热光子主要来源于夸克-反夸克湮灭和夸克-胶子康普顿散射过程。此外,来自于碰撞早期初始部分子硬散射过程和硬光生过程的快喷注也会穿过热夸克-胶子等离子体,与热部分子反生夸克-反夸克湮灭和夸克-胶子康普顿散射相互作用而产生热双轻子、热光子和大横动量轻矢量介子。对于热双轻子不变质量谱,来自半弹性和深度非弹性硬光生过程的喷注-双轻子转换和Drell-Yan过程的贡献是主要的。从数值结果可以看出,在大型强子对撞机(LHC)能区,对于热双轻子、热光子和大横动量轻矢量介子产生,来自深度非弹性硬光生过程的喷注-媒介相互作用的贡献是很显著的。最后,随着夸克-胶子等离子体的膨胀冷却到临界温度时,热系统将会进入夸克-胶子等离子体和强子的混合相,并在固有时刻τH时完全进入强子相,随着热强子气体的膨胀并在固有时刻τf时达到强子冻结温度Tf,热强子系统进入强子冻结状态。在热强子气体中,低质量双轻子主要来源于ππ→l+l-过程,低转移动量光子主要来源于ππ→γγ、ππ→γρ、ππ→γη、πρ→π和πη-÷γπ过程,由于αρ=2.9,因此低转移动量光子最主要的产生机制是πρ→γπ过程。在相对论重离子对撞机(RHIC)和大型强子对撞机(LHC)能区,来自于热强子气体的低不变质量双轻子和低转移动量光子的贡献是很重要的。
[Abstract]:In relativistic heavy ion collisions, perturbative quantum chromodynamics (perturbative Quantum Chromodynamics, pQCD) in the central region of the material energy predicted collision density can be high enough and the formation of quark matter phase. The lifting of the ban in high energy heavy ion collision, collision center area mass density is high the material from the hadron quark matter phase into the lifting of the ban phase (Glasma and quark gluon plasma), and then continue to return to the quark hadron phase expansion cooling. When the material is in Glasma and the hot quark gluon plasma phase, two lepton quark matter molecular interaction between the central and the photon of light vector mesons (P, Omega, phi) will carry the quark matter information. This paper research the Relativistic Heavy Ion Collider (Relativistic Heavy Ion Collider, RHIC) and the Large Hadron Collider (Large Hadron, Collider, LHC) in relativistic nucleus nucleus The spatial and temporal evolution of quark matter produced in the collision and dileptons, photon, light vector mesons hardphotoproduction processes, as well as the color glass condensate (colour glass, condensate, CGC, Glasma), quark gluon plasma (quark-gluon plasma, QGP) and hot gas (hadronic hadron gas, HG) dileptons in the photon and light vector mesons. Early in relativistic nucleus nucleus collision, momentum transfer dileptons, photons and light vector mesons mainly originates from the initial part of the sub hard scattering process, hardphotoproduction processes and fragmentation process. Part of the sub hard scattering process is mainly quark antiquark annihilation, quark gluon the son of Compton scattering and the gluon gluon fusion process. Hardphotoproduction processes including elastic hard double photon process, semi elastic (direct and decomposition) hardphotoproduction processes and deep inelastic (direct and decomposition) hardphotoproduction processes. In hardphotoproduction processes, the original incident The nucleus (nucleus of charged molecules) high-energy photons will launch by quark photon Compton scattering with another incident in the nuclear Parton gluon photon polymerization produced by the interaction of photons and dileptons, light vector mesons. In hardphotoproduction decomposition process, the nuclear incident (in charge of nuclear molecular emission) high-energy photons will fluctuate through the class of Hadron molecules, and the fluctuation part with another incident in the nuclear part by quark antiquark annihilation, Compton scattering and quark gluon gluon gluon fusion produced by the interaction of dileptons photon, and light vector mesons. In addition, in the fragmentation process, fast injection in fractured double lepton, before the photon and light vector mesons, will pass through the nuclear material medium and loss of energy (jet quenching), fast jet energy loss after the broken double lepton, light And the light vector mesons. From the numerical results can be seen in the Large Hadron Collider (LHC) dileptons region P-P and Pb-Pb in the collision, collision, photon and light vector mesons hardphotoproduction processes, fragmentation contribution is significant. However, condensed in the color glass gluon saturation frame. The gluon density will be saturated and color glass condensate in momentum transfer is less than the gluon saturation momentum Qs (CGC), and then in the two nuclear states collide with the color glass condensate will form a nonequilibrium material Glasma. high gluon density in the relativistic case, the gluon saturation momentum will be far Qs greater than the QCD confinement scaling AQCD which makes the running coupling constant s (Qs) <1, so we can calculate dileptons color glass condensate in the use of KT- factor, produce photons and light vector mesons. Condensed gluon saturation region, in the light color glass dileptons. The interaction process and light vector mesons mainly from gluon gluon fusion. The numerical results can be seen in the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) P-P region Au-Au collision, collision, collision and collision p-Pb Pb-Pb, from dileptons low transfer the amount of color glass condensate, low photon momentum transfer and low transfer weight vector meson contribution is very important. In addition, condensed in the color glass gluon saturation under the framework of the relativistic nuclear regional energy density is very high and the center of nuclear collisions can form high gluon density Glasma state, while the Glasma is still not thermal equilibrium is reached, but in the gluon dominated gluon saturation state. The gluon gluon saturation saturation region, Qs momentum will be far greater than the QCD confinement scaling a QCD so that the running coupling constant s (Qs) 1, will be at the Glasma as a Weak coupling system and can be described by relativistic dynamics theory. In Glasma, the low mass dileptons mainly originates from the quark antiquark annihilation process, low quantity of heat transfer mainly from photon quark antiquark annihilation, Compton scattering and quark gluon gluon gluon polymerization process, and the Glasma is a leading gluon, so low momentum transfer is the main contribution of thermal photons from the gluon gluon fusion. The numerical results can be seen in the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) region, from the low quality Glasma constant dilepton and low photon momentum transfer contribution is very significant. Then, with the expansion of Glasma in natural time when Glasma will th the heat of formation of thermalized quark gluon plasma, in the hot quark gluon plasma low mass dileptons mainly derived from quark Anti quark annihilation process, thermal photons mainly from quark antiquark annihilation and quark gluon Compton scattering process. In addition, from the early part of the initial fast jet sub hard scattering process and hardphotoproduction processes of the collision will also wear hot quark gluon plasma, and the hot part of anti quark - anti sub health the quark quark gluon annihilation and Compton scattering from the interaction of thermal dileptons, thermal photons and large transverse momentum of light vector mesons. The thermal dilepton invariant mass spectrum, from semi elastic and deep inelastic hardphotoproduction processes of injection - dileptons conversion and Drell-Yan process is the main contribution from the numerical. The results can be seen in the Large Hadron Collider (LHC) energy region for thermal dileptons, thermal photons and large transverse momentum of light vector mesons produced from deep inelastic hardphotoproduction processes of injection - media interaction contribution is very significant. Finally, with the quark gluon plasma expansion cooling to the critical temperature, the system will enter the mixed hot quark gluon plasma and hadronic phase, and at the moment when the inherent tau H completely into the hadronic phase, with the expansion of the gas and hot hadronic inherent in the moment tau f reached the freezing temperature of Tf hot hadron hadron. The system into the frozen state. In hadron hadron gas heat, low mass dileptons Pi Pi, mainly from the l+l- process, low photon momentum transfer mainly from PI to PI gamma gamma, PI, PI gamma rho, Pi Pi, ETA gamma, PI, PI and PI ETA Rho - pi / gamma process by in the alpha Rho =2.9, so the low photon momentum transfer were the main mechanisms of PI, PI gamma rho. In Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) energy region from hot hadronic gas low mass dileptons constant and low photon momentum transfer contribution is very important.

【学位授予单位】：云南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O572.33

【相似文献】