Strange particle cross sections and multiplicity distributions in 19 GeV/c proton-proton interactions

Inclusive cross sections are presented for strange-particle production in proton-proton interactions at 19 GeV/c for the pairs $\text{(}\text{K}{}^0\text{K}{}^0{}_{\mathrm{C=+1}}\text{,}\text{K}{}^0\text{Λ,}\text{K}{}^{\mathrm{+}}\text{Λ,}\text{K}{}^0\text{Σ}{}^{\mathrm{+}}\text{,}\text{K}{}^0\text{Σ}{}^{\mathrm{?}}$ and for Λ, K_s⁰, Σ⁺, Σ^? and Ξ^?. The $\text{K}\text{K}$, the KY and the total strange particle cross sections have been found to be 1.40 ± 0.10 mb, 2.69 ± 0.09 mb and 4.23 ± 0.20 mb, respectively. The charged multiplicity distributions for events with K_s⁰, Λ, $\text{(}\text{K}{}^0\text{K}{}^0\text{)}{}_{\mathrm{C=+1}}$ or K⁰ Λ are shown to follow a modified KNO curve, whereas K⁺ Λ does not. For the inclusive reactions $\text{pp}\text{→(}\text{K}{}^0\text{K}{}^0\text{)}{}_{\mathrm{C=+1}}\text{+}\text{X}{}^{\mathrm{++}}\text{,}\text{pp}\text{→}\text{K}{}^0\text{Λ +}\text{X}{}^{\mathrm{++}}\text{and pp}\text{→ Λ +}\text{X}{}^{\mathrm{++}}$, we find that the average charged multiplicity of the remainder system X⁺⁺ is the same as when X⁺⁺ is produced in other reactions with the same system energy and quantum numbers.     

Total cross section,inelasticity, and multiplicity distributions in proton-proton collisions

Multiparticle production in high-energy proton-proton collisions has been analyzed in the framework of the strongly correlated quark model of the hadron structure elaborated by the author. It is shown that inelasticity decreases at high energies and the violation of KNO scaling is a consequence of total cross-section growth and increases with collision energy masses of intermediate clusters.     

Analytical expressions for multiplicity distributions and deviations from KNO scaling

A simple method is presented for deducing multiplicity distributions from a few multiplicity moments. The essence of the method is the straightforward trick of converting a discrete distribution to a continuous distributions by interpolation. Interpolation changes the moments by calculable amounts, which depend only on the interpolation procedure and not on the multiplicity distribution. This device makes it possible to give a simple analytical expression for the multiplicity distribution, even at rather low energies, in terms of the measured moments. A quantitative discussion of KNO scaling, and deviations from scaling, is given, based on the measured moments.     

IR-improved DGLAP-CS theory: Kernels, parton distributions, reduced cross sections

It is shown that exact, amplitude-based resummation allows IR-improvement of the usual DGLAP-CS theory. This results in a new set of kernels, parton distributions and attendant reduced cross sections, so that the QCD perturbative result for the respective hadron-hadron or lepton-hadron cross section is unchanged order-by-order in α_s at large squared-momentum transfers. We compare these new objects with their usual counter-parts and illustrate the effects of the IR-improvement in some phenomenological cases of interest with an eye toward precision applications in LHC physics scenarios.     

Sensitivity of reaction cross sections to halo nucleus density distributions

In order to clear up the sensitivity of the nucleus-nucleus reaction cross sections σ _R to the nuclear matter distributions in exotic halo nuclei, we have calculated the values of σ _R for scattering of ⁶He, ¹¹Li, and ¹⁹C nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon. The calculations were performed in the “rigid target” approximation to the Glauber theory, different shapes of the nuclear density distributions in ⁶He, ¹¹Li, and ¹⁹C being assumed.     

Cross sections and multiplicity distributions forK + p interactions at 70 GeV/c

Cross sections and charged multiplicity distributions forK ⁺ p interactions at 70 GeV/c are presented and compared withK ⁺ p data at other energies. Comparisons are also made with available π⁺ p,pp, andK ^? p data.     

Very high energy multiplicity distributions

Within a geometrical model developed in earlier papers, a change of regime, or a “knee,” is predicted in the multiplicity distributions at large multiplicities. The position and motion of this knee is related to geometrical and KNO scaling and their violation, in particular, the rise of the ratio σ_el/σ _t , as well as to the transition from shadowing to antishadowing, expected at LHC energies.     

Moment analysis of multiplicity distributions

Moment analysis of global multiplicity distributions previously done for e ⁺ e ^? and hh processes is applied to hA and AA collisions. Oscillations of cumulants as functions of their rank are found in all processes for which experimental data are available. A similar oscillation pattern is found in the dual parton model and quark-gluon string models but not in the phenomenological fits such as modified negative binomial distributions. The zeros of the truncated generating function move closer and closer to the unity circle in the complex z-plane when the complexity of the collision increases.     

Sensitivity of cross sections for elastic nucleus-nucleus scattering to halo nucleus density distributions

In order to clear up the sensitivity of the nucleus-nucleus scattering to the nuclear matter distributions in exotic halo nuclei, we have calculated differential cross sections for elastic scattering of the ⁶He and ¹¹Li nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon with different assumed nuclear density distributions in ⁶He and ¹¹Li.     

Restricted cross sections

Multiparticle processes with only neutral final state particles are shown to be useful to study multiperipheral dynamics without the presence of recently introduced corrections due to diffraction, clusterings, multi-Pomeranchukon contribution, etc.     

Entropy in multiparticle production and ultimate multiplicity scaling

The entropy S = − ΣP(n) ln P(n) of multiplicity distributions of charged particles in hadron-hadron collisions is investigated. The observed linear increase of S with maximum possible CMS rapidity Y_m, S = (0.417 ± 0.009) Y_m, may be a special case of a more general scaling S/Y_m = F(y_c/Y_m, found in (pseudo) rapidity windows |y| <y_c. We predict an ultimate multiplicity scaling in the few TeV region.     

Geometric scaling for the total gamma(*)p cross section in the low x region

We observe that the saturation model of deep inelastic scattering predicts a geometric scaling of the total gamma(*)p cross section in the region of small Bjorken variable x. The geometric scaling in this case means that the cross section is a function of only one dimensionless variable tau = Q(2)R(2)(0)(x), where the function R(0)(x) decreases with decreasing x. We show that the experimental data from HERA in the region x<0.01 confirm the expectations of this scaling over a very broad region of Q(2). We suggest that the geometric scaling is more general than the saturation model.     

Theoretical spectral distributions and total cross sections for neutral subthreshold pion production in carbon-carbon collisions

With use of a recently developed particle-hole theory for pion production from coherent isobar formation and decay, calculations of total cross sections and kinetic-energy distributions for neutral subthreshold pions produced in carbon-carbon collisions at incident energies below 100 MeV/nucleon are made and compared with recent experimental data.     

Negative binomial multiplicity distributions and intranuclear cascade

The multiplicity distribution of the ejected particles, as predicted by the intranuclear cascade model, are analyzed in terms of negative binomial shapes, which have recently been shown to be relevant for high-energy collisions. We discuss some physical features which are related to this distribution shape.     

On the calculation of scattering cross sections from absorption cross sections

A dispersion-type relation between photon scattering and absorption cross sections is derived. It is shown that the relation gives the correct scattering cross section in the low and high frequency limits, and is consistent with the Kramers-Heisenberg formula in the vicinity of a resonance. The practical application of the relation is illustrated by calculations of the scattering cross section and refractive index of He and Ne at STP and dry air at 1200°K from known absorption cross section data. The method is useful for obtaining scattering cross sections, polarizabilities, and refractive indices at elevated temperatures.