# What Do the New LHC Results on W_{R} Hint About Grand Unified Theories?

01 Jan 2016-pp 671-676

TL;DR: In this paper, it was shown that the result can be accommodated by the extended survival hypothesis and also shed some light on the Higgs content of such GUTs with a range in the range 1.8-2.4 TeV.

Abstract: Searches by the CMS collaboration for the \(W_R\) at \(\sqrt{s} = 8\) TeV have seen a \(2.8\sigma \) excess in the electron channel for an invariant final state mass (\(m_{\textit{eejj}}\)) in the range 1.8–2.4 TeV. It has been shown in the literature that this excess is compatible with models where \(g_R \approx 0.6 g_L\). We analyse the CMS result in the light of \(\textit{SO}(10)\) GUTs and show that the result can be accommodated by \(\textit{SO}(10)\) models with TeV range \(\textit{SU}(2)_R\) breaking and D-parity breaking above \(10^{12}\) GeV. In our analysis we respect the extended survival hypothesis and also shed some light on the Higgs content of such \(\textit{SO}(10)\) models.

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TL;DR: In this paper, it is suggested that a unified description of leptons and hadrons can be obtained within a nonabelian gauge theory where the gauge group is a symmetry group of a set of massless elementary fermions (leptons, quarks).

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TL;DR: In this article, it was shown that the presence of such structures may cause conflict with standard cosmology, and the Spin(10) grand-unified-theory model may not be a good fit for such structures.

Abstract: Extended structures consisting of walls bounded by strings appear in some unified gauge theories. The Spin(10) grand-unified-theory model provides the simplest example, provided the symmetry breaking proceeds via SU(4)\ifmmode\times\else\texttimes\fi{}SU(2)\ifmmode\times\else\texttimes\fi{}SU(2). It is shown that the presence of such structures may cause conflict with standard cosmology.

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Vardan Khachatryan

^{1}, Albert M. Sirunyan^{1}, Armen Tumasyan^{1}, Wolfgang Adam +2124 more•Institutions (141)TL;DR: A search for heavy, right-handed neutrinos in the left-right symmetric extensions of the standard model was performed by the CMS experiment as discussed by the authors, and the search was based on a sample of two lepton plus two jet events collected in proton-proton collisions at a center-of-mass energy of 8.7 �

Abstract: A search for heavy, right-handed neutrinos, $$\mathrm {N}_{\ell }$$
(
$$\ell = \mathrm {e}, \mu $$
), and right-handed $$\mathrm {W}_{\mathrm {R}}$$
bosons, which arise in the left-right symmetric extensions of the standard model, has been performed by the CMS experiment. The search was based on a sample of two lepton plus two jet events collected in proton–proton collisions at a center-of-mass energy of 8
$$\,\text {TeV}$$
corresponding to an integrated luminosity of 19.7
$$\mathrm{fb}^{-1}$$
. For models with strict left-right symmetry, and assuming only one $$\mathrm {N}_{\ell }$$
flavor contributes significantly to the $$\mathrm {W}_{\mathrm {R}}$$
decay width, the region in the two-dimensional $$(M_{\mathrm {W}_{\mathrm {R}}}, M_{\mathrm {N}_{\ell }})$$
mass plane excluded at a 95 % confidence level extends to approximately $$M_{\mathrm {W}_{\mathrm {R}}} = 3.0\,\text {TeV} $$
and covers a large range of neutrino masses below the $$\mathrm {W}_{\mathrm {R}}$$
boson mass, depending on the value of $$M_{\mathrm {W}_{\mathrm {R}}}$$
. This search significantly extends the $$(M_{\mathrm {W}_{\mathrm {R}}}, M_{\mathrm {N}_{\ell }})$$
exclusion region beyond previous results.

199 citations

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TL;DR: In this article, the authors study extensions of the Standard Model with general new vector bosons and derive the corresponding effective Lagrangian, valid at energies lower than the mass of the extra vectors, and use it to extract limits from electroweak precision observables.

Abstract: We study extensions of the Standard Model with general new vector bosons. The full Standard Model gauge symmetry is used to classify the extra vectors and constrain their couplings. We derive the corresponding effective Lagrangian, valid at energies lower than the mass of the extra vectors, and use it to extract limits from electroweak precision observables, including LEP 2 data. We consider both universal and nonuniversal couplings to fermions. We study the interplay of several extra vectors, which can have the effect of opening new regions in parameter space. In particular, it allows to explain the anomaly in the bottom forward-backward asymmetry with perturbative couplings. Finally, we analyze quantitatively the implications for the Higgs mass.

161 citations

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TL;DR: In this article, a new approach to the left-rightsymmetric models of weak interactions where parity and parity-and R-breaking scales are decoupled from each other was proposed.

Abstract: We propose a new approach to the left-right-symmetric models of weak interactions where parity-and ${\mathrm{SU}(2)}_{R}$-breaking scales are decoupled from each other. This changes the spectrum of Higgs bosons, which in turn affects the evolution of various gauge coupling constants with energy. This has profound implications for mass hierarchies in partial unification models based on ${\mathrm{SU}(2)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{SU}(2)}_{R}\ifmmode\times\else\texttimes\fi{}{\mathrm{SU}(4)}_{C}$ and grand unified SO(10) models. We find several interesting SO(10)-breaking chains with and without an intermediate ${\mathrm{U}(1)}_{R}$ symmetry for which both ${M}_{{W}_{R}^{\ifmmode\pm\else\textpm\fi{}}}$ and ${M}_{{Z}_{R}}$ masses are in the range of 1-20 TeV. We also find a symmetry-breaking pattern for which the ${\mathrm{SU}(4)}_{C}$-breaking scale is in the range of ${10}^{5}$ GeV. These patterns lead to observable $\ensuremath{\Delta}B=2$ as well as other right-handed-current effects at low energies.

156 citations