Description of the neutralino observables in terms of projectors

Gounaris, G. J.; Mouël, Christophe Le; Porfyriadis, P. I.

doi:10.1103/physrevd.65.035002

Cited by 22 publications

(54 citation statements)

References 18 publications

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“…Physically, the projector matrix of a mass-eigenstate neutralino is identified with its density matrix in the space of the neutral gaugino and higgsino fields. If the neutralinos were Dirac particles, physical observables would only depend on these projectors; so that an explicit dependence on the CP eigensigns, signals contributions generated by the Majorana nature of the neutralinos [9]. Analytic expressions for these CP eigensigns and projector matrices, as well as the physical masses, in terms of the real SUSY parameters M 1 , µ and M 2 were given in [9].…”

Section: Introductionmentioning

confidence: 99%

“…A description of neutralinos in terms of their projectors has already been proposed in [9], where the restriction to real M 1 , M 2 , µ parameters was made, corresponding to CP conserving chargino and neutralino sectors.…”

Section: Introductionmentioning

confidence: 99%

“…The first purpose of the present work is to extend the neutralino projector formalism of [9], to the case of complex SUSY parameters. The formalism is applied to the MSSM case containing four neutralinos with complex (or real) couplings; but it can be straightforwardly extended to any neutralino number.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless in [9], inspired by Jarlskog's treatment of the CKM matrix [10], we have added to the previous descriptions a new one, which describes each physical neutralino in terms of its projector matrix and its CP eigensign η j = ±1. Physically, the projector matrix of a mass-eigenstate neutralino is identified with its density matrix in the space of the neutral gaugino and higgsino fields.…”

Section: Introductionmentioning

confidence: 99%

“…The neutralino projector matrices, which acting on the weak-basis fields, project out the neutralino mass eigenstateχ 0 j , are defined by [9] …”

Section: Introductionmentioning

confidence: 99%

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Neutralino projector formalism for complex supersymmetry parameters

Gounaris

Mouël

2002

Phys. Rev. D

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We present a new formalism describing the neutralino physics in the context of the minimal supersymmetric model (MSSM), where CP violation induced by complex M 1 and µ parameters is allowed. The formalism is based on the construction of neutralino projectors, and can be directly generalized to non-minimal SUSY models involving any number of neutralinos. It extends a previous work applied to the real SUSY parameter case. In MSSM, the method allows to describe all physical observables related to a specific neutralino, in terms of its CP eigenphase and three complex numbers called its "reduced projector elements". As an example, σ(e − e + →χ 0 iχ 0 j ) is presented in this language. As the experimental knowledge on the neutralino-chargino sectors is being accumulated, the problem of extracting the various SUSY parameters will arise. Motivated by this, we consider various scenarios concerning the quantities that could be first measured. Analytical disentangled expressions determining the related SUSY parameters from them, are then derived, which emphasize the efficiency of the formalism.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The neutralino projector matrices, which acting on the weak-basis fields, project out the neutralino mass eigenstateχ 0 j , are defined by [9] …”

Section: Introductionmentioning

confidence: 99%

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Neutralino projector formalism for complex supersymmetry parameters

Gounaris

Mouël

2002

Phys. Rev. D

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Prospects and blind spots for neutralino dark matter

Cheung

Hall²,

Pinner³

et al. 2013

J. High Energ. Phys.

198

271

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Using a simplified model framework, we assess observational limits and discovery prospects for neutralino dark matter, taken here to be a general admixture of bino, wino, and Higgsino. Experimental constraints can be weakened or even nullified in regions of parameter space near 1) purity limits, where the dark matter is mostly bino, wino, or Higgsino, or 2) blind spots, where the relevant couplings of dark matter to the Z or Higgs bosons vanish identically. We analytically identify all blind spots relevant to spin-independent and spin-dependent scattering and show that they arise for diverse choices of relative signs among M 1 , M 2 , and µ. At present, XENON100 and IceCube still permit large swaths of viable parameter space, including the well-tempered neutralino. On the other hand, upcoming experiments should have sufficient reach to discover dark matter in much of the remaining parameter space. Our results are broadly applicable, and account for a variety of thermal and non-thermal cosmological histories, including scenarios in which neutralinos are just a component of the observed dark matter today. Because this analysis is indifferent to the fine-tuning of electroweak symmetry breaking, our findings also hold for many models of neutralino dark matter in the MSSM, NMSSM, and Split Supersymmetry. We have identified parameter regions at low tan β which sit in a double blind spot for both spin-independent and spin-dependent scattering. Interestingly, these low tan β regions are independently favored in the NMSSM and models of Split Supersymmetry which accommodate a Higgs mass near 125 GeV.1

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CP in the dark

Azevedo

Ferreira

Mühlleitner

et al. 2018

J. High Energ. Phys.

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We build a model containing two scalar doublets and a scalar singlet with a specific discrete symmetry. After spontaneous symmetry breaking, the model has Standard Model-like phenomenology, as well as a hidden scalar sector which provides a viable dark matter candidate. We show that CP violation in the scalar sector occurs exclusively in the hidden sector, and consider possible experimental signatures of this CP violation. In particular, we study contribution to anomalous gauge couplings from the hidden scalars.PACS numbers: I. INTRODUCTIONThe LHC discovery of a scalar with mass of 125 GeV [1, 2] completed the Standard Model particle content. The fact that precision measurements of the properties of this particle [3,4] indicate that it behaves very much in a Standard Model (SM)-like manner is a further confirmation of the validity and effectiveness of that model. Nonetheless, the SM leaves a lot to be explained, and many extensions of the theory have been proposed to attempt to explain such diverse phenomena as the existence of dark matter, the observed universal matter-antimatter asymmetry and others. In particular, numerous SM extensions consist of enlarged scalar sectors, with singlets, both real and complex, being added to the SM Higgs doublet [5][6][7][8][9][10][11][12][13]; or doublets, the simplest example of which is the two-Higgs doublet model (2HDM) [14,15]. Certain versions of singlet-doublet models provide dark matter candidates, as does the Inert version of the 2HDM (IDM) [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Famously, the 2HDM was introduced in 1973 by Lee to allow for the possibility of spontaneous CP violation. But models with dark matter candidates and extra sources of CP violation (other than the SM mechanism of CKM-matrix generated CP violation) are rare. Even rarer are models for which a "dark" sector exists, providing viable dark matter candidates, and where the extra CP violation originates exclusively in the "dark" sector. To the best of our knowledge, the only model with scalar CP violation in the dark sector is the recent work of Refs. [31,32], for which a three-doublet model was considered. The main purpose of Refs. [31,32] was to describe the dark matter properties of the model. In Ref. [33] an argument was presented to prove that the model is actually CP violating, adapting the methods of Refs. [34,35] for the complex 2HDM (C2HDM).In the current paper we will propose a model, simpler than the one in [31], but which boasts the same interesting properties, to wit: (a) a SM-like Higgs boson, h, "naturally" aligned due to the vacuum of the model preserving a discrete symmetry; (b) a viable dark matter candidate, the stability of which is guaranteed by the aforementioned vacuum and whose mass and couplings satisfy all existing dark matter search constraints; and (c) extra sources of CP *

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Description of the neutralino observables in terms of projectors

Cited by 22 publications

References 18 publications

Neutralino projector formalism for complex supersymmetry parameters

Neutralino projector formalism for complex supersymmetry parameters

Prospects and blind spots for neutralino dark matter

CP in the dark

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