A detailed study of the mechanisms of the emissions of pions and protons in the forward and backward hemispheres in 4.5 A GeV/c oxygen-emulsion interactions has been carried out. The correlations between the multiplic...A detailed study of the mechanisms of the emissions of pions and protons in the forward and backward hemispheres in 4.5 A GeV/c oxygen-emulsion interactions has been carried out. The correlations between the multiplicities of secondary charged particles in the backward and forward hemispheres are investigated.展开更多
In this work, we study some changes of nuclear matter in the interactions of <sup>28</sup>Si with emulsion nuclei at 4.5 AGeV/c. From the experimental quantities investigated using Tsallis’ statistics, we...In this work, we study some changes of nuclear matter in the interactions of <sup>28</sup>Si with emulsion nuclei at 4.5 AGeV/c. From the experimental quantities investigated using Tsallis’ statistics, we deduced the temperature, entropy density and non-equilibrium factor of the nuclear medium. These obtained parameters were used to reveal variations in the nuclear matter at the stated interaction energy. The results that came up from this study were compared with their corresponding results obtained from other heavy ion collision experiments at wide energy range.展开更多
Intermittency and fractal behaviour have been studied of emission spectra of target associated fragments from ^84Kr-AgBr interactions at 1.7 A GeV in emission angle space and azimuthal angle space separately. The inte...Intermittency and fractal behaviour have been studied of emission spectra of target associated fragments from ^84Kr-AgBr interactions at 1.7 A GeV in emission angle space and azimuthal angle space separately. The intermittent behaviour is observed in the two spaces separately. Prom the intermittency exponent, the anomalous fractal dimension dq is calculated and the variation of dq with the order q is investigated. It is found that the anomalous dimensions are found to increase with the order of moments q, thereby indicating the relation of multifractality to production mechanism of target associated fragments.展开更多
Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of ...Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of grey, black, and relativistic charged particles can be well represented by Gaussian distribution. The average multiplicity of grey particles is found to increase with the mass of projectile increasing, while that of black particles is found to decrease with the mass of projectile increasing. This result is in good agreement with the prediction of fireball model. Finally, the linear dependence between grey and black particles is observed, but there is no distinct dependence between the production of relativistic charged particles and the target excitation.展开更多
The characteristics of compound particle multiplicity distribution and multiplicity correlations between the compound particle and the grey particle, black particle, shower particle and heavily ionized track particle ...The characteristics of compound particle multiplicity distribution and multiplicity correlations between the compound particle and the grey particle, black particle, shower particle and heavily ionized track particle are investigated in this paper. It is found that the average multiplicities of the grey particle, black particle, shower particle and heavily ionized track particle increase with an increase in the number of compound particles, which can be explained by the impact geometrical model. The compound multiplicity distribution is observed to obey a Koba-Nielson-Olesen （KNO） type of scaling law.展开更多
Self-affine multiplicity fluctuation is investigated by using the two-dimensional factorial moment methodology and the concept of the Hurst exponent （H）. Investigation on the experimental data of compound particles ...Self-affine multiplicity fluctuation is investigated by using the two-dimensional factorial moment methodology and the concept of the Hurst exponent （H）. Investigation on the experimental data of compound particles and target fragments emitted in ^84Kr-AgBr interactions at 1.7 A GeV reveals that the best power law behaviours are exhibited at H=0.7 and 0.6 respectively, and the data for shower particles produced in ^84Kr-emulsion interactions at 1.7 A GeV indicate that the best power law behaviour occurs at H=0.6, all of which show the self-affine multiplicity fluctuation patterns. The multifractality and the non-thermal phase transition occurring during producing the compound particles, the target fragments, and the shower particles in the ^84Kr -AgBr interaction and the ^84Kr-emulsion interaction are also discussed. The multifractality is observed during producing compound particles, target fragments, and shower particles. In the target fragment production, an evidence of non-thermal phase transition is observed, but in the shower particle production and the compound particle production, no evidence of non-thermal phase transition is observed.展开更多
The multiplicity distribution, multiplicity moment, scaled variance, entropy and reduced entropy of target evaporated fragments emitted in forward and backward hemispheres in 12 A GeV ^4He, 3.7 A GeV ^16O, 60 A GeV ^1...The multiplicity distribution, multiplicity moment, scaled variance, entropy and reduced entropy of target evaporated fragments emitted in forward and backward hemispheres in 12 A GeV ^4He, 3.7 A GeV ^16O, 60 A GeV ^16O, 1.7 A GeV ^84Kr and 10.7 A GeV ^197Au -induced emulsion heavy target （AgBr） interactions are investigated. It is found that the multiplicity distribution of target evaporated fragments emitted in both forward and backward hemispheres can be fitted by a Gaussian distribution. The multiplicity moments of target evaporated particles emitted in the forward and backward hemispheres increase with the order of the moment q, and the secondorder multiplicity moment is energy independent over the entire energy range for all the interactions in the forward and backward hemisphere. The scaled variance, a direct measure of multiplicity fluctuations, is close to one for all the interactions, which indicate a correlation among the produced particles. The entropy of target evaporated fragments emitted in both forward and backward hemispheres are the same within experimental errors.展开更多
The intermittency effect has been studied for an interaction of 3.7 A GeV ^16O with emulsion using the distributions of both the pseudorapidity intervals and the azimuthal angle intervals of the shower particles emitt...The intermittency effect has been studied for an interaction of 3.7 A GeV ^16O with emulsion using the distributions of both the pseudorapidity intervals and the azimuthal angle intervals of the shower particles emitted in a central rapidity region. The scaled factorial moments, reduced scaled factorial moments and multifractal moments as functions of the bin size in pseudorapidity and in azimuthal angle have been calculated and have revealed the presence of an intermittent behaviour which may be due to the random cascading property of the reaction. The anomalous fractal dimension has been found to increase with the increase of rank of the moment.展开更多
An exclusive study of the characteristics of interactions accompanied by backward emission（θlab 90°） of shower and grey particles in collisions of a 4.5 AGeV/c ^16O beam with emulsion nuclei is carried out. Th...An exclusive study of the characteristics of interactions accompanied by backward emission（θlab 90°） of shower and grey particles in collisions of a 4.5 AGeV/c ^16O beam with emulsion nuclei is carried out. The experimental multiplicity distributions of different particles emitted in the forward（θlab 〈 90°） and backward hemispheres due to the interactions with the two emulsion components（CNO,AgBr） are presented and analyzed. The correlations between the different emitted particles are also investigated. The results indicate that there are signatures for a collective mechanism,which plays a role in the production of particles in the backward hemisphere. Hence,the backward multiplicity distribution of the emitted shower and grey particles at 4.5 AGeV/c incident momentum can be represented by a decay exponential law formula independent of the projectile size. The exponent of the power was found to increase with decreasing target size. The experimental data favor the idea that the backward particles were emitted due to the decay of the system in the latter stages of the reactions.展开更多
The topology of ^16 O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments, charged secondaries and their dependences on the projectile resi...The topology of ^16 O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments, charged secondaries and their dependences on the projectile residues are discussed.展开更多
The properties of the relativistic helium fragments produced in interactions of ^84Kr at 1.8 A GeV and ^197Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from ...The properties of the relativistic helium fragments produced in interactions of ^84Kr at 1.8 A GeV and ^197Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from various projectiles with emulsion collisions at different energies. It is found that the multiplicity distribution of helium projectile fragments （HPFs） is well described by the Koba-Nielsen Olesen （KNO） scaling presentation. The second Mueller moment f2 of the HPF multiplicity distribution is independent of the projectile energy for the same projectile, but it is dependent on the projectile mass number. The value of f2 increases with the increase of projectile mass number Ap. The negative value of f2, when Ap 〈 69, means that the emission of HPFs is anticorrelated, but positive value of f2, when Ap 〉 69, refers to that the emission of HPFs is correlated. The non-zero f2 moment in this experiment implies the strong correlation existing between the HPFs.展开更多
The forward-backward multiplicity and correlations of a target evaporated fragment （black track particle） and target recoiled proton （grey track particle） emitted from 150 A MeV 4He, 290 A MeV ^12C, 400 A MeV ^12C...The forward-backward multiplicity and correlations of a target evaporated fragment （black track particle） and target recoiled proton （grey track particle） emitted from 150 A MeV 4He, 290 A MeV ^12C, 400 A MeV ^12C, 400 A MeV ^20Ne and 500 A MeV ^56Fe induced different types of nuclear emulsion target interactions are investigated. It is found that the forward and backward averaged multiplicity of a grey, black and heavily ionized track particle increases with the increase of the target size. The averaged multiplicity of a forward black track particle, backward black track particle, and backward grey track particle do not depend on the projectile size and energy, but the averaged multiplicity of a forward grey track particle increases with an increase of projectile size and energy. The backward grey track particle multiplicity distribution follows an exponential decay law and the decay constant decreases with an increase of target size. The backward-forward multiplicity correlations follow linear law which is independent of the projectile size and energy, and the saturation effect is observed in some heavy target data sets.展开更多
A study of intermittency of target associated fragments produced in the interactions of ^16O- AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F4, has been performed. The dependence of t...A study of intermittency of target associated fragments produced in the interactions of ^16O- AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F4, has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variable Х（Z） suggested by Bialas and Gazdzicki. The anomalous dimensions, dq, increase linearly with the order of moments, q. This observation indicates the association of multifractility with production mechanism of target associated fragments.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10475054）, the Major Science and Technology Foundation of Ministry of Education of China （Grant No 205026）, the Natural Science Foundation of Shanxi Province, China（Grant No 20021007） and Shanxi Provincial Foundation for Returned Scholars of China（Grant No 20031046）.
文摘A detailed study of the mechanisms of the emissions of pions and protons in the forward and backward hemispheres in 4.5 A GeV/c oxygen-emulsion interactions has been carried out. The correlations between the multiplicities of secondary charged particles in the backward and forward hemispheres are investigated.
文摘In this work, we study some changes of nuclear matter in the interactions of <sup>28</sup>Si with emulsion nuclei at 4.5 AGeV/c. From the experimental quantities investigated using Tsallis’ statistics, we deduced the temperature, entropy density and non-equilibrium factor of the nuclear medium. These obtained parameters were used to reveal variations in the nuclear matter at the stated interaction energy. The results that came up from this study were compared with their corresponding results obtained from other heavy ion collision experiments at wide energy range.
基金Project supported by the National Natural Science Foundation of China （Grant No 10475054）, the Foundation for Key Program of Ministry of Education of China （Grant No 205026）, the Natural Science Foundation of Shanxi Province, China （Grant No 20021007） and Shanxi Provincial Foundation for Returned Scholars of China （Grant No 20031046）. We are thankful to Professor I. 0tterlund of the Lund University in Sweden for supplying the emulsion plates.
文摘Intermittency and fractal behaviour have been studied of emission spectra of target associated fragments from ^84Kr-AgBr interactions at 1.7 A GeV in emission angle space and azimuthal angle space separately. The intermittent behaviour is observed in the two spaces separately. Prom the intermittency exponent, the anomalous fractal dimension dq is calculated and the variation of dq with the order q is investigated. It is found that the anomalous dimensions are found to increase with the order of moments q, thereby indicating the relation of multifractality to production mechanism of target associated fragments.
基金Project supported by the National Natural Science Foundation of China （Grant No 10475054）, the Major Science and Technology Foundation of Ministry of Education of China （Grant No 205026）, the Natural Science Foundation of Shanxi Province, China （Grant No 20021007） and Shanxi Provincial Foundation for Returned Scholars, China （Grant No 20031046）.
文摘Total disintegration events produced by 4.5 A GeV/c ^16O-AgBr interactions are analysed to investigate the characteristics of secondary charged particles produced in such collisions. The multiplicity distributions of grey, black, and relativistic charged particles can be well represented by Gaussian distribution. The average multiplicity of grey particles is found to increase with the mass of projectile increasing, while that of black particles is found to decrease with the mass of projectile increasing. This result is in good agreement with the prediction of fireball model. Finally, the linear dependence between grey and black particles is observed, but there is no distinct dependence between the production of relativistic charged particles and the target excitation.
基金Supported by National Natural Science Foundation of China (10475054)Natural Foundation of Shanxi Province, China(2008011005)Shanxi Provincial Foundation for Returned Scholars of China
文摘The characteristics of compound particle multiplicity distribution and multiplicity correlations between the compound particle and the grey particle, black particle, shower particle and heavily ionized track particle are investigated in this paper. It is found that the average multiplicities of the grey particle, black particle, shower particle and heavily ionized track particle increase with an increase in the number of compound particles, which can be explained by the impact geometrical model. The compound multiplicity distribution is observed to obey a Koba-Nielson-Olesen （KNO） type of scaling law.
基金supported by the National Natural Science Foundation of China (Grant Nos 10475054 and 10675077)the Research Foundation of Ministry of Education of China (Grant No 205026)+1 种基金the Natural Foundation of Shanxi Province, China (Grant No2008011005)Shanxi Provincial Foundation for Returned Scholars, China (Grant No 20031046)
文摘Self-affine multiplicity fluctuation is investigated by using the two-dimensional factorial moment methodology and the concept of the Hurst exponent （H）. Investigation on the experimental data of compound particles and target fragments emitted in ^84Kr-AgBr interactions at 1.7 A GeV reveals that the best power law behaviours are exhibited at H=0.7 and 0.6 respectively, and the data for shower particles produced in ^84Kr-emulsion interactions at 1.7 A GeV indicate that the best power law behaviour occurs at H=0.6, all of which show the self-affine multiplicity fluctuation patterns. The multifractality and the non-thermal phase transition occurring during producing the compound particles, the target fragments, and the shower particles in the ^84Kr -AgBr interaction and the ^84Kr-emulsion interaction are also discussed. The multifractality is observed during producing compound particles, target fragments, and shower particles. In the target fragment production, an evidence of non-thermal phase transition is observed, but in the shower particle production and the compound particle production, no evidence of non-thermal phase transition is observed.
基金Supported by National Science Foundation of China(11075100)Natural Science Foundation of Shanxi Province(2011011001-2)the Shanxi Provincial Foundation for Returned Overseas Chinese Scholars,(2011-058)
文摘The multiplicity distribution, multiplicity moment, scaled variance, entropy and reduced entropy of target evaporated fragments emitted in forward and backward hemispheres in 12 A GeV ^4He, 3.7 A GeV ^16O, 60 A GeV ^16O, 1.7 A GeV ^84Kr and 10.7 A GeV ^197Au -induced emulsion heavy target （AgBr） interactions are investigated. It is found that the multiplicity distribution of target evaporated fragments emitted in both forward and backward hemispheres can be fitted by a Gaussian distribution. The multiplicity moments of target evaporated particles emitted in the forward and backward hemispheres increase with the order of the moment q, and the secondorder multiplicity moment is energy independent over the entire energy range for all the interactions in the forward and backward hemisphere. The scaled variance, a direct measure of multiplicity fluctuations, is close to one for all the interactions, which indicate a correlation among the produced particles. The entropy of target evaporated fragments emitted in both forward and backward hemispheres are the same within experimental errors.
基金Project supported by the National Natural Science Foundation of China （Grant No 10475054）, the Key Program of Ministry of Education, China （Grant No 205026）, the Natural Science Foundation of Shanxl Province, China （Grant No 20021007） and Shanxi Provincial Foundation for Returned Scholars, China （Grant No 20031046）. We are thankful to Lund University in Sweden plates. Professor 0tterlund I of for supplying the emulsion
文摘The intermittency effect has been studied for an interaction of 3.7 A GeV ^16O with emulsion using the distributions of both the pseudorapidity intervals and the azimuthal angle intervals of the shower particles emitted in a central rapidity region. The scaled factorial moments, reduced scaled factorial moments and multifractal moments as functions of the bin size in pseudorapidity and in azimuthal angle have been calculated and have revealed the presence of an intermittent behaviour which may be due to the random cascading property of the reaction. The anomalous fractal dimension has been found to increase with the increase of rank of the moment.
基金Supported by National Natural Science Foundation of China (10475054, 10675077)Natural Science Foundation of Shanxi Province China (200811005)Shanxi Provincial Foundation for Returned Scholars of China (20031046)
文摘An exclusive study of the characteristics of interactions accompanied by backward emission（θlab 90°） of shower and grey particles in collisions of a 4.5 AGeV/c ^16O beam with emulsion nuclei is carried out. The experimental multiplicity distributions of different particles emitted in the forward（θlab 〈 90°） and backward hemispheres due to the interactions with the two emulsion components（CNO,AgBr） are presented and analyzed. The correlations between the different emitted particles are also investigated. The results indicate that there are signatures for a collective mechanism,which plays a role in the production of particles in the backward hemisphere. Hence,the backward multiplicity distribution of the emitted shower and grey particles at 4.5 AGeV/c incident momentum can be represented by a decay exponential law formula independent of the projectile size. The exponent of the power was found to increase with decreasing target size. The experimental data favor the idea that the backward particles were emitted due to the decay of the system in the latter stages of the reactions.
基金Project supported by the National Natural Science Foundation of China（Grant Nos 10475054 and 10275042）, the Natural Science Foundation of Shanxi Province, China （Grant No 20021007） and the Shanxi Provincial Foundation for Returned Scholars of China （Grant No 20031046）.
文摘The topology of ^16 O fragmentation at 3.7 A GeV in reactions with emulsion nuclei is presented. The multiplicity distributions of projectile fragments, charged secondaries and their dependences on the projectile residues are discussed.
基金supported by the National Natural Science Foundation of China (Grant Nos 10475054 and 10675077)the Foundation for Key Program of Ministry of Education of China (Grant No 2 05026)+1 种基金the Natural Science Foundation of Shanxi Province, China(Grant No 200801105)the Shanxi Provincial Foundation for Returned Scholars, China
文摘The properties of the relativistic helium fragments produced in interactions of ^84Kr at 1.8 A GeV and ^197Au at 10.7 A GeV in emulsion are investigated. The experimental results are compared with those obtained from various projectiles with emulsion collisions at different energies. It is found that the multiplicity distribution of helium projectile fragments （HPFs） is well described by the Koba-Nielsen Olesen （KNO） scaling presentation. The second Mueller moment f2 of the HPF multiplicity distribution is independent of the projectile energy for the same projectile, but it is dependent on the projectile mass number. The value of f2 increases with the increase of projectile mass number Ap. The negative value of f2, when Ap 〈 69, means that the emission of HPFs is anticorrelated, but positive value of f2, when Ap 〉 69, refers to that the emission of HPFs is correlated. The non-zero f2 moment in this experiment implies the strong correlation existing between the HPFs.
基金Supported by National Science Foundation of China(11075100)Natural Science Foundation of Shanxi Province,China(20110110012)Shanxi Provincial Foundation for Returned Overseas Chinese Scholars,China(2011-058)
文摘The forward-backward multiplicity and correlations of a target evaporated fragment （black track particle） and target recoiled proton （grey track particle） emitted from 150 A MeV 4He, 290 A MeV ^12C, 400 A MeV ^12C, 400 A MeV ^20Ne and 500 A MeV ^56Fe induced different types of nuclear emulsion target interactions are investigated. It is found that the forward and backward averaged multiplicity of a grey, black and heavily ionized track particle increases with the increase of the target size. The averaged multiplicity of a forward black track particle, backward black track particle, and backward grey track particle do not depend on the projectile size and energy, but the averaged multiplicity of a forward grey track particle increases with an increase of projectile size and energy. The backward grey track particle multiplicity distribution follows an exponential decay law and the decay constant decreases with an increase of target size. The backward-forward multiplicity correlations follow linear law which is independent of the projectile size and energy, and the saturation effect is observed in some heavy target data sets.
基金National Natural Science Foundation of China(10675077,10475054)Shanxi Provincial Natural Science Foundation(2007011005)Shanxi Provincial Science Foundation for Youths(20051002)
文摘A study of intermittency of target associated fragments produced in the interactions of ^16O- AgBr at 4.5 AGeV/c with nuclear emulsion using the method of factorial moments, F4, has been performed. The dependence of the moments on the number of bins M is found to follow a power law behavior for the experimental data in terms of new scaled variable Х（Z） suggested by Bialas and Gazdzicki. The anomalous dimensions, dq, increase linearly with the order of moments, q. This observation indicates the association of multifractility with production mechanism of target associated fragments.
