高能質(zhì)子鈹作用中領頭粒子λ和δ39;產(chǎn)生的研究

1、三峽大學碩士學位論文高能質(zhì)子-鈹作用中領頭粒子Λ和Δ產(chǎn)生的研究姓名：明庭堯申請學位級別：碩士專業(yè)：應用數(shù)學指導教師：馮笙琴20070401IIIAbstract The main goal of high energy physics experiment is to make an analysis for the data theoretically and experimentally by using the huge acce

2、lerators and detectors. One of the most important tasks of relativistic heavy-ion collisions is to make an analysis of the inner material structure by particle physicist. Baryon transport mechanism in p-A interactions h

3、as been an interesting physics topic. A leading particle here refers to the produced particle that carries the highest momentum in p-A collision. Leading baryons in p-A collisions, which carry the baryon quantum numbers

4、of the incident protons, reflect both the dynamics for the baryon number transport mechanism and indirectly the energy partition between leading particles and produced particles. E941 is a unique experiment for the leadi

5、ng particle measurement and study. One of the most important characteristics of its detectors is having the ability of measuring neutron and large coverage of forward rapidity region. At Alternating Gradient Synchrotron

6、in Brookhaven (Brookhaven/AGS) there are four experimental data including p-Pb, p-Al, p-Be and p-Cu at 19.6GeV. The invariant mass distribution of leading Λ and + + ?in p-Be collisions at 19GeV/c is presented with a new

7、 iterative algorithm through studying distribution of the pairs of proton and pion. In addition we also present distributions of the invariant multiplicity and dn/dy for leading Λ in p-Be collisions, compared with the r

8、esults for p-Pb. These investigations will help us to understand baryon numbers transport mechanism in p-A collisions more deeply. Comparing with the results for p-Pb, we find that the more of heavy target, the less prob

9、ability of the strange quark’s production with the increasing of the rapidity, but nearly the same at midrapidity. However, the p/n ratio in p-Be interactions is nearly same with that in p-Pb interactions, this can indi

10、cates more strongly that the simple diquark-quark fragmentation scheme, which predicts a proton to neutron ratio of two, in unlikely to be the only relevant process in p-A collisions for leading baryons in our rapidity a

11、cceptance. In order to explain a p/n ratio of unity we have to include other fragmentation schemes, perhaps even dominating over the diquark-quark fragmentation in the relevant kinematics region, such as three quark frag