The study of cluster phenomenon at accelerator energies

Correlation between the particles from the proton-nucleus interactions in emulsion at 70 GeV/c is presented through the study of the rapidity gap analysis and compared with the two-particle rapidity correlations. It is observed that the strength of correlation decreases as the size of cluster increases. Asymmetry between the forward and backward components were also studied.Authors are thankful to Prof. K. D. Tolstov, JINR, Dubna, USSR for sending the exposed emulsion plates. Thanks are also due to UGC for financial assistance. We sincerely acknowledge the encouragement from Prof. T. Roy.     

Artificial intelligence–based models for the qualitative and quantitative prediction of a phytochemical compound using HPLC method

Isoquercitrin is a flavonoid chemical compound that can be extracted from different plant species such as Mangifera indica (mango), Rheum nobile , Annona squamosal , Camellia sinensis (tea), and coriander ( Coriandrum sativum L.). It possesses various biological activities such as the prevention of thromboembolism and has anticancer, antiinflammatory, and antifatigue activities. Therefore, there is a critical need to elucidate and predict the qualitative and quantitative properties of this phytochemical compound using the high performance liquid chromatography (HPLC) technique. In this paper, three different nonlinear models including artificial neural network (ANN), adaptive neuro-fuzzy inference system (ANFIS), and support vector machine (SVM),in addition to a classical linear model [multilinear regression analysis (MLR)], were used for the prediction of the retention time (tR) and peak area (PA) for isoquercitrin using HPLC. The simulation uses concentration of the standard, composition of the mobile phases (MP-A and MP-B), and pH as the corresponding input variables. The performance efficiency of the models was evaluated using relative mean square error (RMSE), mean square error (MSE), determination coefficient (DC), and correlation coefficient (CC). The obtained results demonstrated that all four models are capable of predicting the qualitative and quantitative properties of the bioactive compound. A predictive comparison of the models showed that M3 had the highest prediction accuracy among the three models. Further evaluation of the results showed that ANFIS–M3 outperformed the other models and serves as the best model for the prediction of PA. On the other hand, ANN–M3proved its merit and emerged as the best model for tR simulation. The overall predictive accuracy of the best models showed them to be reliable tools for both qualitative and quantitative determination.     

Target mass dependence of charged particle multiplicity inp-nucleus interactions

The shower particle multiplicity (〈n _s 〉) in thep-nucleus interactions for different targets, in the incident energy range of ～6–500 GeV has been studied. The variation of multiplicity parameters with target mass (A) or with number of interactions that the incident hadron suffers inside the nucleus (v _A ) and with the changed particle multiplicity inp-p interactions (〈n _ch〉) has been examined in the light of the various models of multiparticle production. The present analysis favours the hydrodynamical model though some other models can not be conclusively ruled out.     

Distribution of Shower Particles as Obtained in the Analysis of a 10 + 13p Shower Event

We present here the analysis of an accelerator produced 10 + 13p shower event observed in nuclear emulsion. The DULLER -WALKER method is applied to obtain the distribution of secondary shower particles, and the particles having the closest log₁₀ tan θ_L values are taken to form a cluster. This cluster formation is also confirmed by the target diagram method. If this cluster is conceived to be a high spin resonance and the secondary pions to be the decay products of this resonance, then the azimuthal integral distribution curve fits fairly well with our experimental data.     

Search for narrow structure in proton-antiproton annihilation cross sections from 1900 to 1960 MeV

The p?p annihilation cross section has been measured with good resolution (～ 2 MeV RMS) in the mass range 1900–1960 MeV. No narrow structures are seen, the 90% confidence level upper limit being 8–12 mb MeV for the integrated area of a resonance in this mass range. However, we do not rule out a very narrow bump-dip structure seen in an earlier experiment in the 1935–1941 MeV mass interval. The data also do not support the existence of a broad structure previously reported at 1937 MeV.     

Relativistic α-particles emitted in Fe-emulsion interactions at 1.7A GeV

Relativistic α-particles have been studied in 423 interactions of Fe in emulsion at 1.7A GeV. Comparisons of the observed angular distribution with that from ¹⁶O-emulsion reactions at 2.1A GeV reveal that more α-particles are observed at large angles in the Fe-emulsion reactions. The α-particles at large angles cannot be explained by fragmentation from a clean-cut spectator. Comparison of the experimental data with moving relativistic Boltzmann distributions shows that a single Boltzmann distribution cannot fit the fragmentation peak and the tail simultaneously. A thermal source (fireball) explaining the tail part of the distribution needs to be formed by a mechanism other than a simple clean-cut participant-spectator process. A large transverse momentum transfer to the spectator before fragmentation may explain the tail.     

Study of Clusters by Rapidity Interval Method at 24 GeV Proton-Nucleus Interaction in Emulsion

We present here the analysis of the distribution of rapidity intervals in Proton-Nucleus interactions at 24 GeV/c in emulsion. The statistics of the rapidity intervals Δ_{k, n} is discussed in terms of Multiperipheral model. The application of such a method is very useful for the analysis of clusterization phenomenon in individual events. The correlation between neighbouring particles in rapidity is observed in small multiplicity events while multiple correlation is observed in high multiplicity events.     

Meson Production Mechanism at 70 GeV

Photoemulsion plates exposed to 70 GeV proton beam from Serpukhov Accelerator, USSR, have been analysed and part of the data has been utilized to obtain the distribution of the secondary particles in order to ascertain their production mechanism in the fireball model. This intermediate state for the production of secondaries has been identified from log tan θ plot and from the target diagram method. The parameters of the fireball were calculated by the method used by AGNESE et al. It is seen that the fireball model is favourable in 16% of the events studied. The average mass of the fireball is found to be (2.80 ± 0.1) GeV and its momentum to equal 169.62 MeV/c. The polar rotated angular distribution gives a good fit to the experimental data.