Searcharxiv⌕ Search

arXiv subjects

S. V. Chekanov

Publications and source records attributed to S. V. Chekanov.

At least 55 records · Page 3Linked to original sources
arXiv2004

Observation of a narrow baryonic state in DIS at HERA

A resonance search has been made in the K^{0}s-p, K^{0}s-pbar and K^{+}p invariant-mass spectra measured with the ZEUS detector at HERA using an integrated luminosity of 121 pb^{-1}. The search was performed in the central rapidity region of inclusive deep inelastic scattering at an ep centre-of-mass energy of 300--318 GeV for exchanged photon virtuality, Q2, above 1 GeV^{2}. The results support the existence of a narrow state in K^{0}s-p and K^{0}s-pbar decay channels, consistent with the pentaquark prediction. No signal was found in the K^{+}p$ decay channel.

hep-ex↗
arXiv2003

Selection and reconstruction of the top quarks in the all-hadronic decays at a Linear Collider

A method of reconstruction of the top quarks produced in the process E+E- -> t\bar{t} -> 6 jets at a Linear Collider (LC) is proposed. The approach does not involve a kinematic fit, as well as assumptions on the invariant masses of the dijets originating from the decays of W bosons and, therefore, the method is expected to be less sensitive to theoretical and experimental uncertainties on the top-mass measurement than traditional reconstruction methods. For the first time, the reconstruction of the top quarks was investigated using the full LC detector simulation after taking into account the background arising from QCD multi-jet production.

hep-ex↗
arXiv2002

Jet algorithms: a minireview

Many jet algorithms have been proposed in the past to study the hadronic final state in E+E-, EP and PP collisions. Here we review some of the most popular, mainly concentrating on the jet algorithms used at HERA and TEVATRON.

hep-ph↗
arXiv2002

Uncertainties on the measurements of the top mass at a future E+E- collider

The uncertainties due to limited knowledge of the multi-hadron final state on the measurements of the top mass at future linear colliders are discussed. The study is performed for E+E- -> tt-bar annihilation events at the centre-of-mass energy of 500 GeV using Monte Carlo models tuned to LEP experiments. The uncertainties are determined for the all hadronic top-decay mode as well as for the lepton-plus-jets channel.

hep-ph↗
arXiv2001

Suppression of multi-gluon fluctuations in jets at a Linear Collider

It was shown that at typical energies and luminosities of an $e^+e^-$ linear collider one can observe a significant suppression of fluctuations of the number of gluons in small angular regions. This property of jets is expected in $e^+e^-$ annihilation as well as in any collision producing high energy quarks which give rise to the QCD gluon cascade. The reduction of multiplicity fluctuations was obtained from perturbative QCD using bunching parameters and then cross checked with a Monte Carlo simulation. The parton-level Monte Carlo simulation confirms the prediction, while the hadron level illustrates that the effect survives the hadronization process.

hep-ph↗
arXiv2000

Issues in Leading Particle and Charm Production in DIS at HERA

A Monte Carlo simulation based on O(alpha_s) QCD matrix elements matched to parton showers shows that final-state hadrons in deep inelastic scattering (DIS) can be used to tag events with a single (anti)quark recoiled against the proton. The method is particularly suited to study the mean charge of leading particles, which is sensitive to fragmentation and sea quark contribution to the proton structure function. We also discuss methods to study the charm production in DIS using the Breit frame.

hep-ph↗
arXiv2000

Bose-Einstein Correlations in e+e- -> W+W- at a Linear Collider

We show that the most popular method to simulate Bose-Einstein (BE) interference effects predicts negligible correlations between identical pions originating from the hadronic decay of different W's produced in e+e- -> W+W- -> 4 jets at typical linear collider energies.

hep-ph↗
arXiv1999

Short-Range and Long-Range Correlations in DIS at HERA

Correlations in deep-inelastic scattering at HERA are investigated in order to test perturbative QCD and quark fragmentation universality. Two-particle correlations at small angular separations are measured in the Breit frame and compared to e+e- collisions. Also presented are the correlations between the current and target regions of the Breit frame.

hep-ex↗
arXiv1998

Long-Range Correlations in Deep-Inelastic Scattering

Multiplicity correlations between the current and target regions of the Breit frame in deep-inelastic scattering processes are studied. It is shown that the correlations are sensitive to the first-order perturbative QCD effects and can be used to extract the behavior of the boson-gluon fusion rates as a function of the Bjorken variable. The behavior of the correlations is derived analytically and analyzed using a Monte Carlo simulation.

hep-ph↗
arXiv1998

Bose-Einstein Correlations and Color Reconnection in W-pair production

We propose a systematic study of Bose-Einstein correlations between identical hadrons coming from different W decays. Experimentally accessible signatures of these correlations as well as of possible color reconnection effects are discussed on the basis of two-particle inclusive densities.

hep-ph↗
arXiv1998

Scale-Invariant Dynamical Fluctuations in Jet Physics

An interpretation of scale-invariant multiplicity fluctuations inside hadronic jets is presented. It is based on the branching mechanism with the angular ordering of soft partons in sequential branchings. A relationship with fractal distributions is demonstrated. The model takes into account the finiteness of the number of particles produced in jets (finite energy) and leads to a good description of the multifractal fluctuations observed in E+E- processes.

hep-ph↗
arXiv1997

Multiplicities, fluctuations and QCD: Interplay between soft and hard physics?

Multiplicity fluctuations are studied both globaly (in terms of high-order moments) and locally (in terms of small phase-space intervals). The ratio of cumulant factorial to factorial moments of the charged-particle multiplicity distribution shows a quasi-oscillatory behaviour similar to that predicted by the NNLLA of perturbative QCD. However, an analysis of the sub-jet multiplicity distribution at perturbative scales shows that these oscillations cannot be related to the NNLLA prediction. We investigate how it is possible to reproduce the oscillations within the framework of Monte-Carlo models. Furthermore, local multiplicity fluctuations in angular phase-space intervals are compared with Monte-Carlo models and with first-order QCD predictions. While JETSET reproduces the experimental data very well, the predictions of the Double Leading Log Approximations and estimates obtained in Modified Leading Log Approximations deviate significantly from the data.

hep-ex↗
arXiv1997

Local properties of local multiplicity distributions in hadronic Z decay

Preliminary results on local multiplicity fluctuations in hadronic Z decays are presented. The data were obtained using the L3 detector at LEP. It is investigated to what extent Monte-Carlo models, which are tuned to reproduce global event-shape variables and single-particle inclusive distributions, can describe the local fluctuations measured by means of bunching parameters.

hep-ex↗
arXiv1997

Local Properties of Local Multiplicity Distributions

Some aspects of applications of bunching parameters are discussed. It is investigated to what extent Monte-Carlo models, which have been tuned to reproduce global event-shape variables and single-particle inclusive distributions, agree with each other.

hep-ph↗