Squark-pair annihilation into quarks at next-to-leading order

Schmiemann, S.; Harz, Julia; Herrmann, Björn; Klasen, M.; Kovařı́k, K.

doi:10.1103/physrevd.99.095015

Cited by 15 publications

(13 citation statements)

References 104 publications

(150 reference statements)

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“…We note though, that a scenario where the depletion of DM is dominated by the annihilation of its coloured co-annihilating partners is realistic. For instance, within the MSSM it is possible to find viable stop-neutralino co-annihilation scenarios where, for small relative mass differences, thet−t † annihilation contributes about 75%−80% to the neutralino depletion rate [21,41]. Implicit in our computations is the hypothesis that the LP and the NLP stay in chemical equilibrium, i.e.…”

Section: Descriptionmentioning

confidence: 99%

Higgs-mediated bound states in dark-matter models

Harz

Petraki

2019

J. High Energ. Phys.

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It has been recently demonstrated that the 125 GeV Higgs boson can mediate a long-range force between TeV-scale particles, that can impact considerably their annihilation due to the Sommerfeld effect, and hence the density of thermal relic dark matter. In the presence of long-range interactions, the formation and decay of particle-antiparticle bound states can also deplete dark matter significantly. We consider the Higgs boson as mediator in the formation of bound states, and compute the effect on the dark matter abundance. To this end, we consider a simplified model in which dark matter co-annihilates with coloured particles that have a sizeable coupling to the Higgs. The Higgs-mediated force affects the dark matter depletion via bound state formation in several ways. It enhances the capture cross-sections due to the attraction it mediates between the incoming particles, it increases the binding energy of the bound states, hence rendering their ionisation inefficient sooner in the early universe, and for large enough couplings, it can overcome the gluon repulsion of certain colour representations and give rise to additional bound states. Because it alters the momentum exchange in the bound states, the Higgs-mediated force also affects the gluon-mediated potential via the running of the strong coupling. We comment on the experimental implications and conclude that the Higgs-mediated potential must be taken into account when circumscribing the viable parameter space of related models.

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Section: Descriptionmentioning

confidence: 99%

Higgs-mediated bound states in dark-matter models

Harz

Petraki

2019

J. High Energ. Phys.

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“…The Sommerfeld effect in electroweak theories has been discussed intensively in the literature [32][33][34][35][36][37][38] and was studied previously for QCD in the context of DM@NLO to which we refer for more details regarding the computation and implementation [26][27][28].…”

Section: B Qed Sommerfeld Correctionsmentioning

confidence: 99%

“…Hence, we performed our final calculation by including the Coulomb potential at leading order only. For further details on the numerical evaluation, we refer to our previous papers [26][27][28].…”

Section: B Qed Sommerfeld Correctionsmentioning

confidence: 99%

“…Over the last decade, we have demonstrated the impact of QCD next-to-leading order (NLO) corrections in the following cases within the MSSM: Gaugino annihilation into quarks [19][20][21][22], neutralino-stop co-annihilation into several final states [23-25], stop-antistop annihilation into electroweak final states [26], and stop-stop annihilation into quarks [27]. Moreover, we have been able to evaluate the theoretical uncertainty of the relic density calculation [28].…”

Section: Introductionmentioning

confidence: 99%

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SUSY QCD-corrected and Sommerfeld-enhanced stau annihilation into heavy quarks with scheme and scale uncertainties

et al. 2019

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We investigate stau-antistau annihilation into heavy quarks in the phenomenological Minimal Supersymmetric Standard Model within the DM@NLO project. We present the calculation of the corresponding cross section including corrections up to O(αs) and QED Sommerfeld enhancement. The numerical impact of these corrections is discussed for the cross section and the dark matter relic density, where we focus on top-quark final states and consider either neutralino or gravitino dark matter. Similarly to previous work, we find that the presented corrections should be included when calculating the relic density or extracting parameters from cosmological observations. Considering scheme and scale variations, we estimate the theoretical uncertainty that affects the prediction of the annihilation cross section and thus the prediction of the relic density. PACS numbers: 12.38.Bx,12.60.Jv,95.30.Cq,95.35.+d * j bran33@uni-muenster.de †

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“…For many years, the lightest supersymmetric (SUSY) particle, the lightest neutralino, stabilised by a discrete R-parity symmetry, has been favoured, since there exist many other theoretical motivations for SUSY [3]. The neutralino relic density [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], direct detection [20] and LHC production cross sections [21][22][23][24][25][26][27] can even be computed with a precision that rivals the experimental one. However, neither the leading direct detection experiment in this mass range, XENON1T [28], nor the LHC [29] have so far produced any evidence for SUSY DM.…”

Section: Introductionmentioning

confidence: 99%

MeV neutrino dark matter: relic density, lepton flavour violation and electron recoil

Fiaschi

Klasen

Vargas

et al. 2019

J. High Energ. Phys.

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Right-handed neutrinos with MeV to GeV mass are very promising candidates for dark matter (DM). Not only can they solve the missing satellite puzzle, the cuspcore problem of inner DM density profiles, and the too-big-to fail problem, i.e. that the unobserved satellites are too big to not have visible stars, but they can also account for the Standard Model (SM) neutrino masses at one loop. We perform a comprehensive study of the right-handed neutrino parameter space and impose the correct observed relic density and SM neutrino mass differences and mixings. We find that the DM masses are in agreement with bounds from big-bang nucleosynthesis, but that these constraints induce sizeable DM couplings to the charged SM leptons. We then point out that previously overlooked limits from current and future lepton flavour violation experiments such as MEG and SINDRUM heavily constrain the allowed parameter space. Since the DM is leptophilic, we also investigate electron recoil as a possible direct detection signal, in particular in the XENON1T experiment. We find that despite the large coupling and low backgrounds, the energy thresholds are still too high and the predicted cross sections too low due to the heavy charged mediator, whose mass is constrained by LEP limits.

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Squark-pair annihilation into quarks at next-to-leading order

Cited by 15 publications

References 104 publications

Higgs-mediated bound states in dark-matter models

Higgs-mediated bound states in dark-matter models

SUSY QCD-corrected and Sommerfeld-enhanced stau annihilation into heavy quarks with scheme and scale uncertainties

MeV neutrino dark matter: relic density, lepton flavour violation and electron recoil

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