Electroweak phase transition and LHC signatures in the singlet Majoron model

Cline, James M.; Laporte, Guillaume; Yamashita, Hideaki; Kraml, S.

doi:10.1088/1126-6708/2009/07/040

Cited by 55 publications

(51 citation statements)

References 63 publications

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“…We focus on models in which fermionic DM particles couple to a new scalar species and argue that the resulting scalar potential may undergo multiple phase transitions, "flip-flopping" between phases in which the symmetry stabilising the DM is intact and a phase where it is broken. Similar behaviour is found in models of electroweak baryogenesis [8][9][10][11][12][13][14], see also [15] for related work. During the broken phase, the initially overabundant DM particles are depleted until their relic density reaches the value observed today.…”

supporting

confidence: 74%

Dark Matter Decay between Phase Transitions at the Weak Scale

Baker

Kopp

2017

Phys. Rev. Lett.

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We propose a new alternative to the Weakly Interacting Massive Particle (WIMP) paradigm for dark matter. Rather than being determined by thermal freeze-out, the dark matter abundance in this scenario is set by dark matter decay, which is allowed for a limited amount of time just before the electroweak phase transition. More specifically, we consider fermionic singlet dark matter particles coupled weakly to a scalar mediator S3 and to auxiliary dark sector fields, charged under the Standard Model gauge groups. Dark matter freezes out while still relativistic, so its abundance is initially very large. As the Universe cools down, the scalar mediator develops a vacuum expectation value (vev), which breaks the symmetry that stabilises dark matter. This allows dark matter to mix with charged fermions and decay. During this epoch, the dark matter abundance is reduced to give the value observed today. Later, the SM Higgs field also develops a vev, which feeds back into the S3 potential and restores the dark sector symmetry. In a concrete model we show that this "vev flip-flop" scenario is phenomenologically successful in the most interesting regions of its parameter space. We also comment on detection prospects at the LHC and elsewhere.The WIMP (Weakly Interacting Massive Particle) paradigm in dark matter physics states that dark matter (DM) particles should have non-negligible couplings to Standard Model (SM) particles. Their abundance today would then be determined by their abundance at freeze-out, the time when the temperature of the Universe dropped to the level where interactions producing and annihilating DM particles become inefficient. In many models these interactions should still be observable today, through residual DM annihilation in galaxies and galaxy clusters, through scattering of DM particles on atomic nuclei, or through DM production at colliders. The conspicuous absence of any convincing signals [1][2][3][4][5][6][7] to date motivates us to look for alternatives to the WIMP paradigm.In this letter, we present a scenario in which the DM abundance is set not by annihilation, but by decay. We focus on models in which fermionic DM particles couple to a new scalar species and argue that the resulting scalar potential may undergo multiple phase transitions, "flip-flopping" between phases in which the symmetry stabilising the DM is intact and a phase where it is broken. Similar behaviour is found in models of electroweak baryogenesis [8][9][10][11][12][13][14], see also [15] for related work. During the broken phase, the initially overabundant DM particles are depleted until their relic density reaches the value observed today. Although the resulting picture of early freeze out, followed by a period of DM decay around the weak scale, is quite generic, we focus here on a concrete example and comment on possible generalisations in the end.Model Framework.-We introduce a complex dark sector scalar S 3 that is a triplet under the SM SU (2) L gauge symmetry and carries zero hypercharge. We take the DM particle to...

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supporting

confidence: 74%

Dark Matter Decay between Phase Transitions at the Weak Scale

Baker

Kopp

2017

Phys. Rev. Lett.

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“…In this work, we revisit the viability of a SFOEWPT in the simplest extension of the SM scalar sector involving one real gauge singlet scalar S, dubbed the "xSM", and analyze its implications for future, precision Higgs studies (for earlier studies of the EWPT dynamics and/or phenomenology of the xSM, see e.g., [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] and references therein). The xSM cannot account for the BAU on its own as it does not contain new sources of CP violation.…”

Section: Introductionmentioning

confidence: 99%

Singlet-catalyzed electroweak phase transitions and precision Higgs boson studies

et al. 2015

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We update the phenomenology of gauge singlet extensions of the Standard Model scalar sector and their implications for the electroweak phase transition. Considering the introduction of one real scalar singlet to the scalar potential, we analyze present constraints on the potential parameters from Higgs coupling measurements at the Large Hadron Collider (LHC) and electroweak precision observables for the kinematic regime in which no new scalar decay modes arise. We then show how future precision measurements of Higgs boson signal strengths and Higgs self-coupling could probe the scalar potential parameter space associated with a strong first-order electroweak phase transition. We illustrate using benchmark precision for several future collider options, including the High Luminosity LHC (HL-LHC), the International Linear Collider (ILC), TLEP, China Electron Positron Collider (CEPC), and a 100 TeV proton-proton collider, such as the Very High Energy LHC (VHE-LHC) or the Super proton-proton Collider (SPPC). For the regions of parameter space leading to a strong first order electroweak phase transition, we find that there exists considerable potential for observable deviations from purely Standard Model Higgs properties at these prospective future colliders.

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“…The possibilities for a SFOEWPT with an additional real singlet scalar (dubbed the "xSM" [17]), along with its phenomenological consequences for collider studies, have been studied extensively [18][19][20][21][22][23][24][25][26][27][28][29]. The xSM implies the existence of two neutral mass eigenstates, H 1;2 , that are mixtures of the neutral doublet and real singlet.…”

Section: Introductionmentioning

confidence: 99%

Standard model with a complex scalar singlet: Cosmological implications and theoretical considerations

2018

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We analyze the theoretical and phenomenological considerations for the electroweak phase transition and dark matter in an extension of the standard model with a complex scalar singlet (cxSM). In contrast with earlier studies, we use a renormalization group improved scalar potential and treat its thermal history in a gauge-invariant manner. We find that the parameter space consistent with a strong first-order electroweak phase transition (SFOEWPT) and present dark matter phenomenological constraints is significantly restricted compared to results of a conventional, gauge-noninvariant analysis. In the simplest variant of the cxSM, recent LUX data and a SFOEWPT require a dark matter mass close to half the mass of the standard model-like Higgs boson. We also comment on various caveats regarding the perturbative treatment of the phase transition dynamics.

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Electroweak phase transition and LHC signatures in the singlet Majoron model

Cited by 55 publications

References 63 publications

Dark Matter Decay between Phase Transitions at the Weak Scale

Dark Matter Decay between Phase Transitions at the Weak Scale

Singlet-catalyzed electroweak phase transitions and precision Higgs boson studies

Standard model with a complex scalar singlet: Cosmological implications and theoretical considerations

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