Quark confinement in the infinite-momentum frame
Quark confinement in the infinite-momentum frame
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DOI：
10.1103/physrevd.19.639
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发表时间：
1979-01
影响因子：
5
通讯作者：
C. Thorn
中科院分区：
文献类型：
--
作者：
C. Thorn
我们在无限动量框架中提出了夸克禁闭问题。动力学自然地被描述为多体问题：夸克和胶子可以被认为是在二维横向空间中移动的非相对论粒子，其机械质量与纵向动量 P/sup +/ 相关。自然的夸克限制机制是胶子沿着连接分离的夸克和反夸克的管子凝结。这种凝结有利于两种情况：（1）裸露胶子无质量的事实将胶子对产生的最小能量降低到零，（2）八位组颜色结构允许胶子形成具有长程吸引最近邻相互作用的链。我们首先在极限 N/sub c/ ..-->.. 无穷大、N/sub c/g/sup 2/ 固定的情况下研究该机制的可行性，其中 N/sub c/ 是理论中的颜色数量。我们详细分析了 N/sub c/ ..-->.. 无穷大动力学的简化版本，它保留了整个问题的基本特征。这个简化的模型展示了夸克禁闭，并将介子描述为相对论开弦。它还产生了 Regge 斜率 ..cap alpha..' 和尺度 ..mu../sub 0/ 之间的关系，在深层非弹性轻体产生中测量：..mu../sub 0//sup 2/ 大约。 = 2/(..pi sqrt..3..cap alpha..')更多 » 大约= 0.4 GeV/sup 2/，与实验数字0.25 GeV/sup 2/相差不远。接下来我们讨论有限N/sub c/的问题。我们认为 1/N/sub c/ 展开很可能具有真空不稳定性，必须在计算 1/N/sub c/ 校正之前对其进行非微扰处理。我们认为，真正的真空是闭合弦的凝聚体，由于哈密顿量中四胶子项固有的排斥相互作用，该弦具有有限的密度。对凝聚态能量密度的粗略估计可得出近似 epsilon 形式的数量级关系。 N/sub c//sup 2//..cap alpha../sup prime2/. epsilon/sup -1/4/ 应该是字符串粗细的粗略估计。« less
We formulate the problem of quark confinement in the infinite-momentum frame. The dynamics is naturally described as a many-body problem: Quarks and gluons can be thought of as nonrelativistic particles moving in the two-dimensional transverse space with mechanical mass related to the longitudinal momentum P/sup +/. A natural quark-confining mechanism is the condensation of gluons along a tube joining a separated quark and antiquark. This condensation is favored by two circumstances: (1) The fact that bare gluons are massless reduces the minimum energy for gluon pair production to zero, and (2) the octet color structure allows gluons to form into chains with long-range attractive nearest-neighbor interactions. We investigate the viability of this mechanism first in the limit N/sub c/ ..-->.. infinity, N/sub c/g/sup 2/ fixed, where N/sub c/ is the number of colors in the theory. We analyze in detail a simplified version of the N/sub c/ ..-->.. infinity dynamics which preserves the essential features of the full problem. This simplified model exhibits quark confinement and describes mesons as relativistic open strings. It also yields a relationship between the Regge slope ..cap alpha..' and the scale ..mu../sub 0/, measured in deep-inelastic leptoproduction: ..mu../sub 0//sup 2/ approx. = 2/(..pi sqrt..3..cap alpha..')more » approx. = 0.4 GeV/sup 2/, which is not too far from the experimental number 0.25 GeV/sup 2/. We discuss next the problem of finite N/sub c/. We argue that the 1/N/sub c/ expansion is likely to have a vacuum instability which must be handled nonperturbatively before 1/N/sub c/ corrections can be calculated. We suggest that the true vacuum is a condensate of closed strings which have a finite density by virtue of repulsive interactions inherent in the four-gluon term in the Hamiltonian. A crude estimate of the condensate energy density yields an order-of-magnitude relation of the form epsilon approx. N/sub c//sup 2//..cap alpha../sup prime2/. epsilon/sup -1/4/ should be a rough estimate of the thickness of the string.« less