arXiv subjects

A. V. Gladyshev

Publications and source records attributed to A. V. Gladyshev.

26 records · Page 2Linked to original sources

arXiv1998

Could we learn more about HERA high $Q^2$ anomaly from LEP200 and TEVATRON? R-parity violation scenario

The excess of high $Q^2$ events at HERA reported in the early 1997 by H1 and ZEUS collaborations has become the subject of extensive studies in the framework of several models related to new physics. Here we concentrate on the most promising, from our point of view, model describing HERA anomaly. We update our previous analysis and take into account new HERA statistics of the 1997 year. HERA events are considered within the R-parity broken SUSY model for a specific scenario with several non-zero couplings. R-parity broken SUSY with several non-zero couplings could explain both high $Q^2 e^+ + jets$ and $μ^+ + jets$ observed at HERA. The consequence of such a particular scenario is the excess of high $Q^2$ di- or tri-jet events at HERA. The relation of this scenario for LEP and TEVATRON colliders is considered. This study shows that if a squark resonance does take place at HERA, supersymmetry with broken R-parity can be revealed at either LEP200 or TEVATRON in the near future.

hep-ph↗

arXiv1998

Higgs Limit and b->s gamma Constraints in Minimal Supersymmetry

New limits on the Higgs mass from LEP and new calculations on the radiative (penguin) decay of the b->s gamma branching ratio restrict the parameter space of the Constrained Minimal Supersymmetric Standard Model (CMSSM). We find that for the low tan(beta) scenario only one sign of the Higgs mixing parameter is allowed, while the high tan(beta scenario is practically excluded, if one requires all sparticles to be below 1 TeV and imposes radiative electroweak symmetry breaking as well as gauge and Yukawa coupling unification. For squarks between 1 and 2 TeV high tan(beta) scenarios are allowed. We consider especially a new high tan(beta)=64 scenario with triple unification of all Yukawa couplings of the third generation, which show an infrared fixed point behaviour. The upper limit on the mass of the lightest Higgs in the low (high) tan(beta) scenarios is 97+-6~(120+-2) GeV, where the errors originate predominantly from the uncertainty in the top mass.

hep-ph↗

arXiv1998

Updated Combined Fit of Low Energy Constraints to Minimal Supersymmetry

The new precise LEP measurements of alphas and the electroweak mixing angle as well as the new LEP II mass limits for supersymmetric particles and new calculations for the radiative (penguin) decay of the b-quark into sgamma allow a further restriction in the parameter space of the Constrained Minimal Supersymmetric Standard Model (CMSSM).

hep-ph↗

arXiv1997

Minimal Supersymmetric Standard Model within CompHEP software package

The Minimal Supersymmetric Standard Model is presented as a model for the CompHEP software package as a set of files containing the complete Lagrangian of the MSSM, particle contents and parameters. All resources of CompHEP with a user-friendly interface are now available for the phenomenological study of the MSSM. Various special features of the model are discussed.

hep-ph↗

arXiv1997

Could we learn more about HERA high Q^2 anomaly from LEP200 and TEVATRON ?

The excess of high Q^2 events at HERA has been the subject of recent extensive studies in the framework of several models related to new physics. Here, we would like to concentrate on the most promising, from our point of view, model describing HERA anomaly. We investigate HERA events within the R-parity broken SUSY model and check its relation to LEP and TEVATRON colliders. This study shows that if a squark resonance really takes place at HERA, supersymmetry with broken R-parity can be revealed at either LEP200 or TEVATRON.

hep-ph↗

arXiv1997

Possibility of Chargino Search at LEP II

We study the potential of the LEP200 collider for chargino production and the possibility of the determination of some fundamental SUSY parameters through the relation with this study. Total cross sections for two basic signatures of pair chargino production and for main backgrounds are calculated. The set of kinematic cuts is proposed for the effective background suppression and extraction of the signal. Calculations and the MC simulation performed give the limits on chargino and neutralino masses that could be obtained at LEP200 with $\sqrt s =$ 200 GeV.

hep-ph↗

arXiv1996

Softly Broken Finite Supersymmetric Grand Unified Theory

In the context of the standard SUSY GUT scenario, we present a detailed analysis of the softly broken finite supersymmetric grand unified theory. The model, albeit non-minimal, remains very rigid due to the requirement of finiteness. It is based on the $SU(5)$ gauge group and is UV finite to all orders of perturbation theory. It contains three generations of the matter fields together with four pairs of Higgses. The requirement of UV finiteness fixes all the Yukawa couplings at the GUT scale. Imposing the condition of universality on the soft couplings at the Planck scale and then extending the condition of finiteness to them, one gets a completely finite unified theory above $M_{GUT}.$ This makes the fine-tuning procedure more meaningful and leads to the usual Minimal Supersymmetric Standard Model below $M_{GUT}$. All the masses of the ordinary particles including Higgses are obtained due to the Higgs mechanism at the electro-weak scale. The hierarchy of quark and lepton masses is related to that of v.e.v.'s of the Higgs fields and is governed by the Higgs mixing matrix in the generation space. Superpartners develop their masses according to the RG equations starting from the soft terms at the Planck scale. The suggestion of complete finiteness and maximal simplicity of the unified theory leads to the connection between the initial values of soft SUSY breaking parameters, namely $m_0^2=1/3m_{1/2}^2,\ A_t=A_b=A_τ=-m_{1/2}, \ B=-m_{1/2}$, so that the number of free parameters is less than that of the MSSM.

hep-ph↗

arXiv1994

Renormalization Group Improved Radiative Corrections to the Supersymmetric Higgs Boson Masses

The one-loop radiative corrections to the Higgs boson potential in the MSSM, originating from the top quark and squark loops, are summed in the leading log approximation using the renormalization group. The RG improved effective potential is minimized and the corrections to the CP-odd and CP-even Higgs boson masses are calculated. The resulting masses exhibit smoother top mass dependence than those calculated without RG summation. We have also found that for preferable values of the top mass the light Higgs mass does not exceed 100 GeV.

hep-ph↗