[en] We consider all possible finite representations of the Lorentz group and their association with the spin properties of the particles. It is shown that, for a given nontrivial spin, there exist several nonequivalent representations differing in chirality, which in the massless case correspond to different particles with different helicities. A spin-1 case, which includes the standard field description by the vector-potential and a non-standard one by the second rank antisymmetric tensor field, is considered in detail. The first field transforms under the real representation (1/2,1/2), while the second one does so under the chiral representations (1,0) and (0,1). By considering spin-1 hadron resonances as an example, it is shown that these two fields describe two different types of particles existing in nature. This idea is further applied to the construction of the Standard Model extension using a new type of spin-1 chiral particles. Its phenomenological consequences are studied in detail.

[en] The gauge coupling unification can be achieved at a unification scale around 5×10"1"3 GeV if the Standard Model scalar sector is extended with extra Higgs-like doublets. The relevant new scalar degrees of freedom in the form of chiral Z* and W* vector bosons might “be visible” already at about 700 GeV. Their eventual preferred coupling to the heavy quarks explains the non observation of these bosons in the first LHC run and provides promising expectation for the second LHC run.

[en] The recent results of the PIBETA experiment strongly suggest the presence of non-V-A anomalous interactions in the radiative pion decay. We assume that they arise as a result of the exchange of new intermediate chiral spin-1 bosons which interact anomalously with matter. Their contribution into the τ decay leads to violation of the CVC hypothesis at the same level as detected experimentally

[en] Fundamental particle physics research at the Joint Institute for Nuclear Research (JINR) has always included the use of highest-energy accelerator machines, and it is only natural that from its very beginning, the institute played an active role in work on developing, assembling, and upgrading both the Large Hadron Collider itself and its detectors. Along with providing hardware and software support to secure the failure-free operation of detectors and the gathering and processing of experimental data, JINR sets as its primary goal to effectively participate in the unprecedentedly comprehensive and important LHC research program. As part of this program, the experimental search for new heavy chiral Z* and W* bosons is carried out by the ATLAS collaboration, an effort whose necessity was fully justified and strategy exhaustively developed by JINR physicists. The search results from the first run of the LHC are briefly discussed, together with the decisive contribution from JINR and future prospects.

[en] A simple reference model for anomalously interacting bosons is proposed and implemented in the CompHEP package. This allows preparing for an experimental search of these bosons at powerful colliders, such as Tevatron and LHC. New signatures and some experimental consequences are shortly considered.

[en] The resonance production of new chiral spin-1 bosons and their detection through the Drell-Yan process at the CERN LHC is considered. Quantitative evaluations of various differential cross sections of the chiral-boson production are made within the CalcHEP package. The new neutral chiral bosons can be observed as a Breit-Wigner resonance peak in the invariant-dilepton-mass distribution, as usual. However, unique new signatures of the chiral bosons exist. First, there is no Jacobian peak in the lepton transverse-momentum distribution. Second, the lepton angular distribution in the Collins-Soper frame for the high on-peak invariant masses of the lepton pairs has a peculiar 'swallowtail' shape.

[en] Properties of low-lying spin-1 hadron resonances are described in the review. It is shown how the Nambu-Jona-Lasinio model can be extended in the chiral invariant way by new tensor interactions. New mass formulas are obtained, which are not based on unitary symmetry groups but involve particles from different multiplets even with opposite parity. They all are in good agreement with experimental data. Dynamic properties of spin-1 mesons confirmed by the calculations performed using the QCD sum rule technique and the lattice calculations are understood and explained.

[en] The main distribution for a bump search is the dilepton-invariant-mass distribution with appropriate cut on an absolute value of pseudorapidity difference Δη ≡ |η₁ − η₂| between the two leptons. The back-ground from the Standard Model Drell-Yan process contributes mainly to the central pseudorapidity region Δη ≈ 0. By contrast, the excited bosons lead to a peak at Δη ≈ 1.76. We show that this property allows one to enhance the significance of their bump search by means of the new cut optimization. Nevertheless, in order to confirm an observation of the bump and reveal the resonance nature, other angular distributions should be used in addition.

[en] With this note we would like to draw attention to a possible novel signal of new physics in dijet data at the hadron colliders. Usually it is accepted that almost all exotic models predict that these two jets populate the central (pseudo)rapidity region where y_1,2 ≅ 0. Contrary, the excited bosons do not contribute into this region, but produce an excess of dijet events over the almost flat QCD background in χ = exp vertical bar y₁-y₂ vertical bar away from this region. For the special choice of parameters this could lead to a dip in the centrality ratio distribution over the dijet invariant mass instead of a bump, expected for the most exotic models.

[en] The e ⁺ e ⁻ and μ⁺μ⁻ dilepton final states are the most clear channels for a new heavy neutral resonance search. Their advantage is that usually in the region of expected heavy-mass resonance peak the main irreducible background, from the Standard Model Drell-Yan process, contributes two orders of magnitude smaller than the signal. In this paper we consider the future prospects for search for the excited neutral Z*-bosons. The bosons can be observed as a Breit-Wigner resonance peak in the dilepton invariant mass distributions in the same way as the well-known extra gauge Z′ bosons. However, the Z* bosons have unique signatures in transverse momentum, angular and pseudorapidity distributions of the final leptons, which allow to distinguish them from the other heavy neutral resonances. At present only the ATLAS Collaboration has looked for such new excitations at the Large Hadron Collider and has published its results for 7 TeV collision energy. After successful comparison of our evaluation with these official results we present our estimations for the discovery potential and the exclusion limits on the Z*-boson search in pp collisions at higher centre-of-mass energies and different luminosities. In particular, LHC Run 2 can discover Z*-boson with its mass up to 5.3 TeV, while the High Luminosity LHC can extend that reach to 6.2 TeV. The High Energy LHC (with collision energy of 33 TeV) will be able to probe two times heavier resonance masses at the same integrated luminosities.