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Naturalness and dark matter in the supersymmetric B−L extension of the standard model

Naturalness and dark matter in the supersymmetric B−L extension of the standard model
Naturalness and dark matter in the supersymmetric B−L extension of the standard model
We study the naturalness properties of the B−L supersymmetric standard model (BLSSM) with type-I seesaw and compare them to those of the minimal supersymmetric standard model (MSSM) at both low (i.e., Large Hadron Collider) energies and high (i.e., unification) scales. By adopting standard measures of naturalness, we assess that, in the presence of full unification of the additional gauge couplings and scalar/fermionic masses of the BLSSM, such a scenario reveals a somewhat higher degree of fine-tuning (FT) than the MSSM, when the latter is computed at the unification scale and all available theoretical and experimental constraints, but the dark matter (DM) ones, are taken into account. Yet, such a difference, driven primarily by the collider limits requiring a high mass for the gauge boson associated to the breaking of the additional U(1)B−L gauge group of the BLSSM in addition to the SU(3)C×SU(2)L×U(1)Y of the MSSM, should be regarded as a modest price to pay for the former in relation to the latter, if one notices that the nonminimal scenario offers a significant volume of parameter space where numerous DM solutions of different compositions can be found to the relic density constraints, unlike the case of the minimal structure, wherein only one type of solution is accessible over an ever diminishing parameter space. In fact, this different level of tension within the two SUSY models in complying with current data is well revealed when the FT measure is recomputed in terms of the low-energy spectra of the two models, over their allowed regions of parameter space now in the presence of all DM bounds, as it is shown that the tendency is now opposite, with the BLSSM appearing more natural than the MSSM.
hep-ph
2470-0010
Delle Rose, Luigi
19c81ce1-e14b-4e4c-b72d-0d74cbb331db
Khalil, Shaaban
2320836f-4666-474a-9aa4-bdfe6eb086b7
King, Simon J.D.
afc72899-531a-4598-b3db-9e1066480783
Marzo, Carlo
e50a7231-60d0-4811-8e20-486747409cc4
Moretti, Stefano
b57cf0f0-4bc3-4e02-96e3-071255366614
Un, Cem S.
25af457e-6050-4ff9-95fa-15a4cef053a4
Delle Rose, Luigi
19c81ce1-e14b-4e4c-b72d-0d74cbb331db
Khalil, Shaaban
2320836f-4666-474a-9aa4-bdfe6eb086b7
King, Simon J.D.
afc72899-531a-4598-b3db-9e1066480783
Marzo, Carlo
e50a7231-60d0-4811-8e20-486747409cc4
Moretti, Stefano
b57cf0f0-4bc3-4e02-96e3-071255366614
Un, Cem S.
25af457e-6050-4ff9-95fa-15a4cef053a4

Delle Rose, Luigi, Khalil, Shaaban, King, Simon J.D., Marzo, Carlo, Moretti, Stefano and Un, Cem S. (2017) Naturalness and dark matter in the supersymmetric B−L extension of the standard model. Physical Review D, 96, [055004]. (doi:10.1103/PhysRevD.96.055004).

Record type: Article

Abstract

We study the naturalness properties of the B−L supersymmetric standard model (BLSSM) with type-I seesaw and compare them to those of the minimal supersymmetric standard model (MSSM) at both low (i.e., Large Hadron Collider) energies and high (i.e., unification) scales. By adopting standard measures of naturalness, we assess that, in the presence of full unification of the additional gauge couplings and scalar/fermionic masses of the BLSSM, such a scenario reveals a somewhat higher degree of fine-tuning (FT) than the MSSM, when the latter is computed at the unification scale and all available theoretical and experimental constraints, but the dark matter (DM) ones, are taken into account. Yet, such a difference, driven primarily by the collider limits requiring a high mass for the gauge boson associated to the breaking of the additional U(1)B−L gauge group of the BLSSM in addition to the SU(3)C×SU(2)L×U(1)Y of the MSSM, should be regarded as a modest price to pay for the former in relation to the latter, if one notices that the nonminimal scenario offers a significant volume of parameter space where numerous DM solutions of different compositions can be found to the relic density constraints, unlike the case of the minimal structure, wherein only one type of solution is accessible over an ever diminishing parameter space. In fact, this different level of tension within the two SUSY models in complying with current data is well revealed when the FT measure is recomputed in terms of the low-energy spectra of the two models, over their allowed regions of parameter space now in the presence of all DM bounds, as it is shown that the tendency is now opposite, with the BLSSM appearing more natural than the MSSM.

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Naturalness and Dark Matter in the BLSSM - Accepted Manuscript
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Submitted date: 6 February 2017
Accepted/In Press date: 30 May 2017
e-pub ahead of print date: 6 September 2017
Additional Information: 28 pages, 18 figures First available on ArXiv 6 Feb 2017 This is theoretical physics, all supporting data is in the paper. no data set required.
Keywords: hep-ph

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Local EPrints ID: 414836
URI: http://eprints.soton.ac.uk/id/eprint/414836
ISSN: 2470-0010
PURE UUID: 2a052e97-cd1d-49e7-b889-5a45ce46c677

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Date deposited: 11 Oct 2017 16:32
Last modified: 06 Oct 2020 17:24

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Contributors

Author: Luigi Delle Rose
Author: Shaaban Khalil
Author: Simon J.D. King
Author: Carlo Marzo
Author: Stefano Moretti
Author: Cem S. Un

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