《相对论重离子碰撞试验的现状及展望》由会员分享，可在线阅读，更多相关《相对论重离子碰撞试验的现状及展望（20页珍藏版）》请在金锄头文库上搜索。
1、Evidence of self-affine target fragmentation process in 197Au-AgBr interactions at 10.7 A GeV,D.H. Zhang, F. Wang, J.X. Cheng, B. Cheng, Q. Wang, H.Q. Zhang, R. Xu Institute of Modern Physics, Shanxi Normal University Linfen 041004, China Sept. 2, 2008 1、Introduction 2、Experimental details 3、Method
2、of Study 4、Experimental Results 5、Conclusions,1. Introduction,In high energy interactions, the study of non-statistical fluctuations have entered into a new era since Bialas and Peschanski(NP B273(1986) 703) introduced an attractive methodology to study non-statistical fluctuations in multiparticle
3、production. They suggested that the scaled factorial moment Fq has a growth following a power law with decreasing phase space interval size and this feature signals the onset of intermittency in the context of high energy interactions. This scaled factorial moment method has the feature that it can
4、measure the non-statistical fluctuations avoiding the statistical noise. Up to now, most of the analysis have been carried out in the relativistic produced particles with the common belief that these particles are the most informative about the reaction dynamics and thus could be effective in reveal
5、ing the underlying physics of relativistic nucleus-nucleus collisions. However, the physics of nucleus-nucleus collisions at high energies is not yet conclusive and therefore all the available probes need to thoroughly exploited towards meaningful analysis of experimental data.,1. Introduction,In re
6、lativistic heavy ion induced nuclear emulsion interactions, the target fragmentation produces highly ionizing particles responsible for heavy tracks which are subdivided into gray and black tracks. The gray tracks are the medium-energy (30-400 MeV) knocked-out target protons (or recoiled protons) wi
7、th range 3 mm and velocity 0.30.7. They are supposed to carry some information about the interaction dynamics because the time scale of the emission of these particles is of the same order (10-22s) as that of the produced particles. The general belief about these recoiled protons is that they are th
8、e low energy part of the internuclear cascade formed in high energy interactions. The black tracks with range 3 mm and velocity 0.3 are attributed to evaporation from highly excited nuclei in the thermodynamically equilibrium state. In the rest system of the target nucleus, the emission direction of
9、 the evaporated particles is distributed isotropically.,1. Introduction,In the analysis of intermittency most of the studies are performed in the one-dimensional space only, but the real process occurs in three dimensions. So one-dimensional analysis is not sufficient enough to make any comment on t
10、he complete dynamical fluctuations pattern. According to Ochs (PL B247(1990) 101), in a lower-dimensional projection the fluctuations will be reduced by the averaging process. In two-dimensional analysis generally the phase space are divided equally in both directions assuming that the phase spaces
11、are isotropic in nature. Consequently self-similar fluctuations are expected. It may happen that the fluctuations are anisotropic and the scaling behavior is different in different directions giving rise to self-affine scaling. So far only a few works have been reported where the evidence of self-af
12、fine multiparticle production is indicated by the data(Ghosh et al., EPJ A14(2002) 77, PR C66(2002) 047901, JP G29(2003) 983, IJMP E13(2004) 1179, MPL A22(2007) 1759, Wang et al., PL B410(1997) 323, Wu and Liu, PRL 70(1993) 3197).,1. Introduction,In most of the earlier works on intermittency, best l
13、inear fits were drawn in the total bin range from some pre-conceived ideas. Actually, the plots are not perfectly linear in the whole bin range, rather nice linear behavior is apparent in selective bin ranges. So it would be better to investigate intermittency in those bin ranges. The intermittency
14、pattern cannot only suggest the dynamical nature of fluctuation but also reveals the inner fractal structure of the fluctuation codimensions dq (Ochs, PL B247 (1990) 101, Bialas and Gazdzicki, PL B252(1990) 483), which are related to the intermittency indices aq as dq=aq/(q-1). Unique dq for a diffe
15、rent order of moments suggests monofractality whereas order dependence of dq signals the presence of multifractality. Multifractality may be due to self-similar cascading, whereas monofractality is associated with thermal transitions. Now, there is a feeling that self-similar cascading is not consis
16、tent with particle creation during one phase but instead requires a non-thermal phase transition.,1. Introduction,According to Peschanski (PL B410(1991) 323) if the dynamics of intermittency is due to self-similar cascading, then there is a possibility of observing a non-thermal phase transition. The signals of non-thermal phase transition can be studied with the help of the parameter q=(aq+1)/q. The condition for non-thermal phase transition may occur whe
