| 1. |
- Beylin, Vitaly, et al.
(author)
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Dark Matter carriers from vector-like Technicolor model. Part I.
- 2015
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Conference paper (peer-reviewed)abstract
- It is shown that Technicolor model can be formulated having vector-like interaction of Techniquarks with the Standard Model bosons and Dirac mass term. Oblique corrections values for the case agree with experimental restrictions. The model Lagrangian is based on σ−model scheme introducing Techni-meson and Techni-baryon states. Neutral component of a "triplet" of heavy scalar Techni-baryons can be considered as Dark Matter particle. Small mixing between scalar states h − σ is in accordance with experiment and is provided by strong relation between masses of Techni-σ and Techni-π .
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| 2. |
- Bi, Xiao Jun, et al.
(author)
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Chapter 5 Dark Matter and New Physics Beyond the Standard Model with LHAASO
- 2022
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In: Chinese Physics C. - : IOP Publishing. - 1674-1137 .- 2058-6132. ; 46:3
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Journal article (peer-reviewed)abstract
- In order to reveal the nature of dark matter, it is crucial to detect its non-gravitational interactions with the standard model particles. The traditional dark matter searches focused on the so-called weakly interacting massive particles. However, this paradigm is strongly constrained by the null results of current experiments with high precision. Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale. The Large High Altitude Air Shower Observatory (LHAASO) with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale. In this document, we review the theoretical motivations and background of heavy dark matter. We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO, and present the projected sensitivities. We also review the prospects of searching for the axion-like particles, which are a kind of well motivated light pseudo-scalars, through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.
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| 3. |
- Pasechnik, Roman, et al.
(author)
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Chiral-symmetric technicolor with standard model Higgs boson
- 2013
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 88:7
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Journal article (peer-reviewed)abstract
- Most of the traditional technicolor-based models are known to be in a strong tension with the electroweak precision tests. We show that this serious issue is naturally cured in strongly coupled sectors with chiral-symmetric vectorlike gauge interactions in the framework of the gauged linear sigma model. We discuss possible phenomenological implications of such a nonstandard chiral-symmetric technicolor scenario in its simplest formulation preserving the standard model (SM) Higgs mechanism. For this purpose, we assume the existence of an extra technifermion sector confined under extra SU(3)(TC) at the energy scales reachable at the LHC, Lambda(TC) similar to 0: 1-1 TeV and interacting with the SM gauge bosons in a chiral-symmetric (vectorlike) way. In the framework of this scenario, the SM Higgs vacuum expectation value acquires a natural interpretation in terms of the condensate of technifermions in confinement in the nearly conformal limit. We study the influence of the lowest-lying composite physical states, namely, technipions, technisigma, and constituent technifermions, on the Higgs sector properties in the SM and other observables at the LHC. We find that the predicted Higgs boson signal strengths in gamma gamma, vector-boson VV*, and fermion f (f) over bar decay channels can be sensitive to the new strongly coupled dynamics and are consistent with the current SM-like Higgs boson observations in the limit of relatively small Higgs-technisigma mixing. At the same time, the chiral-symmetric technicolor provides us with rich technipion phenomenology at the LHC, and its major implications are discussed in detail.
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| 4. |
- Pasechnik, Roman, et al.
(author)
-
Composite scalar dark matter from vector-like SU (2) confinement
- 2016
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In: International Journal of Modern Physics A. - 0217-751X. ; 31:8
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Journal article (peer-reviewed)abstract
- A toy-model with SU(2)TC dynamics confined at high scales ΛTC > 100GeV enables to construct Dirac UV completion from the original chiral multiplets predicting a vector-like nature of their weak interactions consistent with electroweak precision tests. In this work, we investigate a potential of the lightest scalar baryon-like (T-baryon) state B0 = UD with mass mB ≥ 1TeV predicted by the simplest two-flavor vector-like confinement model as a dark matter (DM) candidate. We show that two different scenarios with the T-baryon relic abundance formation before and after the electroweak (EW) phase transition epoch lead to symmetric (or mixed) and asymmetric DM, respectively. Such a DM candidate evades existing direct DM detection constraints since its vector coupling to Z boson absents at tree level, while one-loop gauge boson mediated contribution is shown to be vanishingly small close to the threshold. The dominating spin-independent (SI) T-baryon-nucleon scattering goes via tree-level Higgs boson exchange in the t-channel. The corresponding bound on the effective T-baryon-Higgs coupling has been extracted from the recent LUX data and turns out to be consistent with naive expectations from the light technipion case mπ <ΛTC. The latter provides the most stringent phenomenological constraint on strongly-coupled SU(2)TC dynamics so far. Future prospects for direct and indirect scalar T-baryon DM searches in astrophysics as well as in collider measurements have been discussed.
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| 5. |
- Pasechnik, Roman, et al.
(author)
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Dark Energy from graviton-mediated interactions in the QCD vacuum
- 2013
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In: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :6
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Journal article (peer-reviewed)abstract
- Adopting the hypothesis about the exact cancellation of vacuum condensates contributions to the ground state energy in particle physics to the leading order in graviton-mediated interactions, we argue that the observable cosmological constant can be dynamically induced by an uncompensated quantum gravity correction to them after the QCD phase transition epoch. To start with, we demonstrate a possible cancellation of the quark-gluon condensate contribution to the total vacuum energy density of the Universe at temperatures T < 100 MeV without taking into account the graviton-mediated effects. In order to incorporate the latter, we then calculate the leading-order quantum correction to the classical Einstein equations due to metric fluctuations induced by the non-perturbative vacuum fluctuations of the gluon and quark fields in the quasiclassical approximation. It has been demonstrated that such a correction to the vacuum energy density has a form epsilon(Lambda) similar to G Lambda(6)(QCD), where G is the gravitational constant, and Lambda(QCD) is the QCD scale parameter. We analyze capabilities of this approach based on the synthesis between quantum gravity in quasiclassical approximation and theory of non-perturbative QCD vacuum for quantitative explanation of the observed Dark Energy density.
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| 6. |
- Pasechnik, Roman, et al.
(author)
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Possible compensation of the QCD vacuum contribution to the dark energy
- 2013
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 88:2
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Journal article (peer-reviewed)abstract
- We suggest one of the possible ways to compensate the large negative quantum-topological QCD contribution to the vacuum energy density of the Universe by means of a positive constant contribution from a cosmological Yang-Mills field. An important role of the exact particular solution for the Yang-Mills field corresponding to the finite-time instantons is discussed. An interesting connection of the compensation mechanism to the color confinement in the framework of instanton models has been pointed out. Besides the Lambda(QCD) scale, this proposal relies on one dimensionless normalization constant which cannot be fixed by the perturbative QCD theory, and thus should be fine-tuned for the exact compensation to hold.
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| 7. |
- Pasechnik, Roman, et al.
(author)
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Vector-like technineutron Dark Matter: is a QCD-type Technicolor ruled out by XENON100?
- 2014
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In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 74:2
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Journal article (peer-reviewed)abstract
- One of the specific predictions of a new strongly coupled dynamics at a TeV scale is the existence of stable vector-like technibaryon states so that the lightest neutral one could serve as a Dark Matter candidate. We study the latter hypothesis in the QCD-type technicolor with SU (3)(TC) confined group and one SU (2)(W) doublet of vector-like techniquarks consistent with electroweak precision constraints and test it against the existing Dark Matter astrophysics data. We discuss the most stringent Dark Matter constraints on weak interactions of technibaryons in SU (3)(TC) technicolor and possible implications of these findings for the cosmological evolution of relic technineutrons. We conclude that vector-like techniquark sectors with an odd group of confinement SU(2n + 1)(TC), n = 1, 2, ... and with ordinary vector-like weak SU (2)(W) interactions are excluded by XENON100 data under the assumption of technibaryon number conservation in the modern Universe allowing for an even technicolor group SU (2n)(TC) only.
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