Medium dependence of multiplicity distributions in MLLA
نویسندگان
چکیده
We study the modification of the multiplicity distributions in MLLA due to the presence of a QCD medium. The medium is introduced though a multiplicative constant (fmed) in the soft infrared parts of the kernels of QCD evolution equations. Using the asymptotic ansatz for quark and gluons mean multiplicities 〈nG〉 = e γy and 〈nQ〉 = r e respectively, we study two cases: fixed γ as previously considered in the literature, and fixed αs. We find opposite behaviors of the dispersion of the multiplicity distributions with increasing fmed in both cases. For fixed γ the dispersion decreases, while for fixed αs it increases.
منابع مشابه
Particle spectra at ZEUS
Charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 38.6pb −1. The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic center-of-mass frame. The KNO-scal...
متن کاملJet Fragmentation and Mlla
Recent CDF results on inclusive momentum distributions and multiplicities of particles in restricted cones around jets are compared to predictions using the Modified Leading Log Approximation. We found that MLLA gives a very reasonable description of jet fragmentation for a wide range of energies. Model parameters are extracted separately from the multiplicity and from the shape of the momentum...
متن کاملQcd Evolution of Hadron and Jet Multiplicity Moments *
We describe recent applications of the MLLA evolution equations to the calculation of mean multiplicities in quark and gluon jets and the higher moments of hadron and sub-jet multiplicity distributions in e + e −-annihilation as function of c.m.s. energy Q and resolution parameter ycut. The transition from jets to hadrons with increasing jet resolution is considered.
متن کاملAverage charged multiplicity of events containing heavy quarks in e+e- annihilation.
We present the MLLA results for heavy quark event multiplicities in e+eannihilation, which provide that the difference 6Ql between heavy and light quark event multiplicities at the same ems energy should be a calculable constant, independent of ems energy. Published data on heavy quark event multiplicities are presented in this light, and are consistent with the energy independence of the multi...
متن کاملMultiplicity and Event Shape in the Perturbative QCD
The multiple hadroproduction in the perturbative QCD is briefly reviewed. There are a number of quantities which can be analysed with the use of the high-luminosity TRISTAN data. The analysis will contribute to clarifying some unsolved questions, and to the deeper understanding of the jet physics. When a coloured particle is produced at a high energy, a number of hadrons are produced predominan...
متن کامل