Deciphering the spin of new resonances in Higgsless models

Physical review D: Particles and fields 10/2008; DOI: 10.1103/PhysRevD.79.035009
Source: arXiv

ABSTRACT We study the potential of the CERN Large Hadron Collider (LHC) to probe the spin of new massive vector boson resonances predicted by Higgsless models. We consider its production via weak boson fusion which relies only on the coupling between the new resonances and the weak gauge bosons. We show that the LHC will be able to unravel the spin of the particles associated with the partial restoration of unitarity in vector boson scattering for integrated luminosities of 150-560 fb^-1, depending on the new state mass and on the method used in the analyses. Comment: 7 pages, 4 figures. Version published in Physical Review D

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    ABSTRACT: The appearance of spin-1 resonances associated with the electroweak symmetry breaking sector is expected in many extensions of the standard model. We analyze the CERN Large Hadron Collider potential to probe the spin of possible new charged and neutral vector resonances through the purely leptonic processes pp→Z′→ℓ+ℓ′-ET, and pp→W′→ℓ′±ℓ+ℓ-ET, with ℓ, ℓ′=e or μ. We perform a model-independent analysis and demonstrate that the spin of the new states can be determined with 99% C.L. in a large fraction of the parameter space where these resonances can be observed with 100 fb-1. We show that the best sensitivity to the spin is obtained by directly studying correlations between the final state leptons, without the need of reconstructing the events in their center-of-mass frames.
    Physical review D: Particles and fields 05/2011; 83(9).
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    ABSTRACT: In this thesis we investigated, at partonic level and leading order, the LHC potencial operating with $\sqrt{s}=14$ TeV and integrated luminosity of $L=100\;{fb}^{-1}$ to probe "pure" (without triple vertex contributions) anomalous electroweak quartic couplings, $WWWW$ and $WWZZ$, in the semileptonic $pp \rightarrow l^{\pm}\nu_{l}jjjj$ channel, enhanced by the Vector Boson Fusion collider signatures. Deviations on SM quartic couplings were parameterized in a model independent approach, realized linearly ($L_{S0}$ and $L_{S1}$ operators) or not ($L_{4}$ and $L_{5}$ operators), on the basis of effective lagrangians. Being our analysis essentially events counting-and-cut based, we took into account all possible backgrounds (irreducible, QCD and top quarks processes) considered at ${\cal O}(\alpha_{em}^{6})$, ${\cal O(\alpha_{em}^{4}\alpha_{s}^{2})$ and ${\cal O}(\alpha_{em}^{2}\alpha_{s}^{4})$. In this way, we have obtained the following constraints for the non-linear $\alpha_{4}$ and $\alpha_{5}$ anomalous couplings: $|\alpha_{4,5}| \lesssim 0.01$ to 0.02 at 3$\sigma$. Based on non-linear results, we have estimated, for a specific choice of factorization and renormalization scale, the linear parameters $f_{0}$ and $f_{1}$ constraints as $-22 \leq \dfrac{f_{0}}{\Lambda^{4}}\;({TeV}^{-4}) \leq 20, \quad {and} \quad -26 \leq \dfrac{f_{1}}{\Lambda^{4}}\;({TeV}^{-4}) \leq 24$ at 3$\sigma$. On a different approach, manipulating one extension of the SM named $331_{RHN}$, we have evaluated the contribution of new sources of FCNC for the difference of mass of neutral meson systems, $K_{0}-\bar{K_{0}}$, $D^{0}-\bar{D^0}$ and $B^0_d-\bar{B^0_d}$. Bounds related to these systems may be significantly strengthened in the presence of these new interactions allowing stronger constraints on the parameter space of the model.
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    ABSTRACT: Determining the spin of new particles is an important tool for discriminating models beyond the Standard Model. We show that in case of cascades of subsequent two body decays the existing strategy to extract the spin from lepton and quark spectra can be used without changes even if one allows for dim-5 and dim-6 operators which might be induced by physics just beyond the reach of LHC. We show analytically that these operators do not change the overall structure of these spectra.


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