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V. Vechernin

Publications and source records attributed to V. Vechernin.

5 recordsLinked to original sources

A high-resolution pixel silicon Vertex Detector for open charm measurements with the \NASixtyOne spectrometer at the CERN SPS

The study of open charm meson production provides an efficient tool for the investigation of the properties of hot and dense matter formed in nucleus-nucleus collisions. The interpretation of the existing di-muon data from the CERN SPS suffers from a lack of knowledge on the mechanism and properties of the open charm particle production. Due to this, the heavy-ion programme of the \NASixtyOne experiment at the CERN SPS has been extended by precise measurements of charm hadrons with short lifetimes. A new Vertex Detector for measurements of the rare processes of open charm production in nucleus-nucleus collisions was designed to meet the challenges of track registration and high resolution in primary and secondary vertex reconstruction. A small-acceptance version of the vertex detector was installed in 2016 and tested with Pb+Pb collisions at 150\AGeVc. It was also operating during the physics data taking on Xe+La and Pb+Pb collisions at 150\AGeVc conducted in 2017 and 2018. This paper presents the detector design and construction, data calibration, event reconstruction, and analysis procedure.

physics.ins-det

On the Interpretation of the Balance Function

We construct a simple toy model and explicitly demonstrate that the Balance Function (BF) can become negative for some values of the rapidity separation and hence can not have any probabilistic interpretation. In particular, the BF can not be interpreted as the probability density for the balancing charges to occur separated by the given rapidity interval.

hep-ph

The dependence of the number of pomerons on the impact parameter and the long-range rapidity correlations in pp collisions

The simple model which enables to take into account the effects of a colour string fusion in pp interactions is suggested. The parameters of the model are connected with the parameters of the pomeron trajectory and its couplings to hadrons. On the base of the model the MC algorithm which enables to calculate the long-range correlation functions between multiplicities and between the average transverse momentum and the multiplicity in pp collisions is developed.

nucl-th

Transverse Momentum Dependence of Cumulative Pions

In the framework of the recently proposed QCD based parton model for the cumulative phenomena in the interactions with nuclei the dependence of the cumulative pion production rates on the transverse momentum is studied. The mean value of the transverse momentum is found to grow with x in the cumulative region. The obtained results are in agreement with the available experimental data.

hep-ph

Structure Functions and Particle Production in the Cumulative Region: two different exponentials

In the framework of the recently proposed QCD based parton model for the cumulative phenomena in the interactions with nuclei two mechanisms for particle production, direct and spectator ones, are analysed. It is shown that due to final state interactions the leading terms of the direct mechanism contribution are cancelled and the spectator mechanism is the dominant one. It leads to a smaller slope of the cumulative particle production rates compared to the slope of the nuclear structure function in the cumulative region $x>1$, in agreement with the recent experimental data.

hep-ph