Physics at LHC
We review the physics to be investigated at LHC. We also describe the main parameters of CMS and ATLAS detectors.
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arXiv subjects
N. V. Krasnikov
Publications and source records attributed to N. V. Krasnikov.
Two-loop calculations for the propagators of gluonic currents. Erratum
This is an erratum to the paper published in Nucl. Phys. B198(1982)508.
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PLANCKSUSY - new program for SUSY masses calculations: from Planck scale to our reality
We describe briefly new program for SUSY masses calculations. The main distinction of our program is that we start to solve the renormalization group equations for soft SUSY breaking parameters for SU(5) SUSY GUT model from Planck scale $M_{PL} = 2.4\cdot 10^{18}$ Gev. Our program works also for large $tan(β)$. We find that for $m_0 \leq 0.5 \cdot m_{1/2}$ the effects of the evolution from Planck scale to GUT scale are very essential. In particular, we find that neutralino even for small $m_0$ is always LSP. We also introduced in our program some parameter of non-universality of the gaugino masses at GUT scale. Playing with the non-universality of the gaugino masses at GUT scale it is possible to have the situation when leptonic modes are suppressed and the single SUSY signature is hadronic jets with missing energy.
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Search for flavor lepton number violation in slepton decays at LHC
We show that in supersymmetric models with explicit flavor lepton number violation due to soft supersymmetry breaking mass terms there could be detectable flavor lepton number violation in slepton decays. We estimate LHC discovery potential of the lepton flavor number violation in slepton decays.
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The masses of vector supermultiplet and of the Higgs supertriplet in supersymmetric SU(5) model
The masses of vector supermultiplet and of the Higgs supertriplet in standard supersymmetric SU(5) model are calculated. Taking into account uncertainties related with the initial coupling constants and threshold corrections we find that in supersymmetric SU(5) model the scale of the supersymmetry breaking could be up to 50 Tev. We find that in the extensions of the standard SU(5) supersymmetric model it is possible to increase the supersymmetry breaking scale up to $O(10^{12})$ Gev. In standard supersymmetric SU(5) model it is possible to increase the GUT scale up to $5 \cdot 10^{17}$ Gev provided that the masses of chiral superoctets and supertriplets are $m_{3,8} \sim O(10^{13}) Gev$. We also propose SU(5) supersymmetric model with 6 light superdoublets and superoctet with a mass $O(10^{9})$ Gev.
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Infrared modified analysis for the $τ$ lepton width
We argue that accounting for higher order corrections in QCD by integrating a running coupling constant through an infrared region can be most easily done with making use of a scheme without the Landau pole. Within this approach the entire ambiguity of the answer is identical to that of the choice of renormalization scheme. The uncertainties for the $τ$ lepton width resulting from such a technique are discussed.
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Bound states of singlet quarks at LHC
We discuss the discovery potential of the bound states of singlet quarks at LHC. We find that it is possible to discover bound states of singlet quarks at LHC with singlet quark masses up to 300 Gev for $e_{Q} = \frac{2}{3}$ and up to 200 Gev for $e_{Q} = -\frac{1}{3}$.
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Renormalization schemes and renormalons
We describe some ways how higher order corrections can reveal themselves if integrated over the infrared region. We show that in different renormalization group (RG) schemes and for some observables one has no factorial divergences. We argue that for treating things in the infrared region it is preferable to start with a RG scheme without the infrared Landau pole in the running coupling constant. The uncertainties for the $τ$ lepton width resulting from accounting for higher order corrections are discussed.
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SUSY model with R-parity violation, longlived charged slepton and quasistable matter
We construct SUSY $SU(3) \otimes SU(2)_{L} \otimes U(1)$ electroweak models with superweak R-parity. The scale of R-parity violation in one of the models is determined by the Majorana mass of neutrino and it is very small that leads to the existence of longlived ($ T \geq O(10^{-4}sec$) lightest superparticle. If lightest superparticle is righthanded charged slepton that can be realized within gaugino dominated scenario then the phenomenology of such model differs in a drastic way from the standard SUSY phenomenology, in particular, longlived charged sleptons can form bound states with ordinary matter - quasistable supermatter (SUSY analogs of mu-atoms and muonium). We discuss possible manifestations of the existence of such longlived charged particle at LEP2, TEVATRON and LHC. We also construct $SU(3) \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)$ model with Majorana mass and superweak R-parity violation.
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Bubble chain resummation and universality
We propose a parameterization for contributions of an infinite set of diagrams (bubble chains) into physical observables represented as integrals of running coupling constant over the finite region in momentum space. The perturbation theory part of contributions is rendered well-defined by the principal value prescrition for treating the Landau pole while the rest is connected to the gluon condensate in case of observables allowing the OPE analysis. The hypothesis of universality, i.e. the use of our parameterization for non-OPE cases, is discussed.
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Search for flavor lepton number violation in slepton decays at LEP2 and NLC
We show that in supersymmetric models with explicit flavor lepton number violation due to soft supersymmetry breaking terms there must be flavor lepton number violation in slepton decays. We propose to look for flavor lepton number violation in righthanded selectron and smuon decays. For selectron and smuon lighter than 80 Gev flavor lepton number violation in slepton decays could be discovered at LEP2 provided the mixing betwen selectron and smuon is not small. We also estimate NLC discovery potential of the lepton flavor number violation in slepton decays.
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The search for nonstandard Higgs bosons at FNAL and LHC
We discuss the phenomenology of many Higgs doublet model - the model where each Higgs isodoublet couples with each own quark and lepton with relatively big Yukawa coupling constants. Namely, we discuss the discovery potential of the Higgs bosons at LHC and find lower mass limits on nonstandard Higgs bosons from FNAL data.
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The phenomenology of scalar octets
We discuss the phenomenology of colour scalar octets. Namely, we consider the discovery potential of scalar octets at LEP, FNAL and LHC. Scalar octets decay mainly into two gluons and new hadrons composed from scalar colour octets are rather long lived $(Γ\leq O(10)Kev)$. For the scalar octet masses $M \geq O(50)Gev$ scalar octets producing at FNAL or LHC decay into two gluons that leads to additional four-jet events. We propose to look for scalar octets by the measurement of the distributions of differential cross sections on the invariant di-jet masses. Scalar octets naturally arise in models with compactification of additional space dimensions. In such models the branching ratio for the scalar octet bound state into two photons is $O(10^{-2})$ that leads to the events with two photons and two jets. We also point out that the current experimental data don't contradict to the existence of light ($M \sim O(1)Gev$) scalar octets. Light scalar octets give additional contribution into QCD $β$-function and allow to improve the agreement between deep inelastic and LEP data.
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Bound on nonlocal scale from LEP
Leptons, quarks and gauge bosons are assumed to be described by local field theory. Stringent bounds on nonlocal scale can be derived from the high- presision LEP measurements. We find a bound on nonlocal scale $Λ_{nl} > 1020\: Gev$, C.L.95\% from LEP data.
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Upper bound on the supersymmetry breaking scale in supersymmetric SU(5) model.
The status of coupling constant unification in standard supersymmetric SU(5) model and its extensions is discussed. Taking into account uncertainties related with the initial coupling constants and threshold corrections at low and high scales we find that in supersymmetric SU(5) model the scale of supersymmetry breaking could be up to $10^8$ Gev. In the extensions of standard SU(5) model it is possible to increase the supersymmetry breaking scale up to $10^{11}$ Gev.
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