High-Spatial-Resolution Monitoring of Strong Magnetic Field using Rb vapor Nanometric-Thin Cell

We have implemented the so-called $\lambda$-Zeeman technique (LZT) to investigate individual hyperfine transitions between Zeeman sublevels of the Rb atoms in a strong external magnetic field $B$ in the range of $2500 - 5000$ G (recently it was established that LZT is very convenient for the range of $10 - 2500$ G). Atoms are confined in a nanometric thin cell (NTC) with the thickness $L = \lambda$, where $\lambda$ is the resonant wavelength 794 nm for Rb $D_1$ line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field with the frequency positions and transition probabilities depending on the $B$-field. Possible applications are described, such as magnetometers with nanometric local spatial resolution and tunable atomic frequency references.Comment: 12 page

Intermittency and Correlations at LEP and at HERA

A review on recent investigations of local fluctuations and genuine correlations in electron-positron annihilations at LEP and in positron-proton collisions at HERA is given.Comment: Invited talk given at the XXXth Int. Symposium on Multiparticle Dynamics (ISMD 2000), 9-15 October 2000, Tihany, Lake Balaton, Hungar

Multiplicities and particle production at LEP

Recent results on hadron multiplicities in heavy and light quark fragmentation above the Z peak (OPAL), and multiplicity distribution analysis (L3) and inclusive f_1 production (DELPHI) in hadronic Z decays are presented.Comment: 3 pages, 4 figs. Talk given at the International Europhysics Conference on High Energy Physics, EPS-HEP2003, 17-23 July 2003, Aachen, German

Multiplicities and Correlations at LEP

A brief review on recent charge multiplicity and correlation measurements at LEP is given. The measurements of unbiased gluon jet multiplicity are discussed. Recent results on charged particle Bose-Einstein and Fermi-Dirac correlations at LEP1 are reported. New results on two-particle correlations of neutral pions are given. Correlations of more than two particles (high-order correlations) obtained using different methods are performed. Recent Bose-Einstein correlation measurements at LEP2 are discussed.Comment: 5 pages. Invited talk presented at the Xth International Workshop on Deep Inelastic Scattering (DIS2002), Cracow, 30 April - 4 May 200

Study of Multiparticle Spikes in Central 4.5A GeV/c C-Cu Collisions

An analysis of local fluctuations, or spikes, is performed for charged particles produced in central C-Cu collisions at 4.5 GeV/$c$/nucleon. The distributions of spike-centers and the maximum density distributions are investigated for different narrow pseudorapidity windows to search for multiparticle dynamical correlations. Two peaks over statistical background are observed in the spike-center distributions with the structure similar to that expected from the coherent gluon radiation model and recently found in hadronic interactions. The dynamical contribution to maximum density fluctuations are obtained to be hidden by statistical correlations, though behavior of the distributions shows qualitative agreement with that from the one-dimensional intermittency model. The observed features of the two different approaches, coherent vs. stochastic, to the formation of the local dynamical fluctuations are discussed.Comment: 12 pages, LaTeX, 2 eps fig

Dual coherent particle emission as generalized two-component Cherenkov-like effect

In this Letter we introduce a new kind of coherent particle production mechanism called dual coherent particle emission (DCPE) as generalized two-component Cherenkov-like effect, which takes place when the phase velocity of emitted particle v_{Mph} and the particle source phase velocity v_{B_1ph} satisfy a specific DCPE condition: v_{Mph} <= v_{B_1ph}^{-1}. The general signatures of the DCPE in dielectric, nuclear and hadronic media are established and some experimental evidences are presented.Comment: 12 pages, 4 fig

Dual coherent particle emission as generalised Cherenkov-like effect in high energy particle collisions

In this paper we introduce a new kind of nuclear/hadronic coherent particle production mechanism in high-energy collisions called \emph{dual coherent particle emission (DCPE)} which takes place when the phase velocities of the emitted particle v_{Mph} and that of particle source v_{B_1ph} satisfy the dual coherence condition: v_{Mph} <= v_{B_1ph}^-1. The general signatures of the DCPE in the nuclear and hadronic media are established and some experimental evidences are given.Comment: 5 pages, 5 eps figs., revtex4 styl

The ridge effect and three-particle correlations

Pseudorapidity and azimuthal three-particle correlations are studied based on a correlated-cluster model of multiparticle production. The model provides a common framework for correlations in proton-proton and heavy-ion collisions allowing easy comparison with the measurements. It is shown that azimuthal cluster correlations are definitely required in order to understand three-particle correlations in the near-side ridge effect. This is similar to the explanation of the ridge phenomenon found in our previous analysis of two-particle correlations and generalizes the model to higher-order correlations.Comment: 16 pages, 7 figures. arXiv admin note: text overlap with arXiv:1610.0640

Relating multihadron production in hadronic and nuclear collisions

The energy-dependence of charged particle mean multiplicity and pseudorapidity density at midrapidity measured in nucleus-nucleus and (anti)proton-proton collisions are studied in the entire available energy range. The study is performed using a model, which considers the multiparticle production process according to the dissipating energy of the participants and their types, namely a combination of the constituent quark picture together with Landau relativistic hydrodynamics. The model reveals interrelations between the variables under study measured in nucleus-nucleus and nucleon-nucleon collisions. Measurements in nuclear reactions are shown to be well reproduced by the measurements in (anti)proton-proton interactions common and the corresponding fits are presented. Different observations in other types of collisions are discussed in the framework of the proposed model. Predictions are made for measurements at the forthcoming LHC energies.Comment: Europ. Phys. J. C (to appear). Recently CMS reported (arXiv:1005.3299) on the midrapidity density value of 5.78 +/- 0.01(stat) +/- 0.23(syst) in pp collisons at 7 TeV, which agrees well with the value of 5.8 of our prediction