Pion–nucleon sigma term revisited in covariant baryon chiral perturbation theory

Ren, Xiu-Lei; Ling, Xi-Zhe; Geng, Li-Sheng

doi:10.1016/j.physletb.2018.05.063

Cited by 34 publications

(20 citation statements)

References 45 publications

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“…where q 2 is the DM momentum transfer when it scatters against nucleons. Here m N and f N ≈ 0.3 represent the nucleon mass and its SM Higgs coupling [20][21][22], respectively. In the third line, we have only kept the leading-order dependence on the momentum transfer.…”

Section: Tree-level Contributions To the Dm-nucleon Scattering At Finmentioning

confidence: 99%

One-loop contribution to dark-matter-nucleon scattering in the pseudo-scalar dark matter model

Azevedo

Duch

Grza̧dkowski

et al. 2019

J. High Energ. Phys.

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Recent dark matter (DM) direct searches place very stringent constraints on the possible DM candidates proposed in extensions of the Standard Model. There are however models where these constraints are avoided. One of the simplest and most striking examples comes from a straightforward Higgs portal pseudoscalar DM model featured with a softly broken U (1) symmetry. In this model the tree-level DM-nucleon scattering cross section vanishes in the limit of zero momentum-transfer. It has also been argued that the leading-order DM-nucleon cross section appears at the one-loop level. In this work we have calculated the exact cross section in the zero momentum-transfer at the leading-order i.e., at the one-loop level of perturbative expansion. We have concluded that, in agreement with expectations, the amplitude for the scattering process is UV finite and approaches zero in the limit of vanishing DM masses. Moreover, we made clear that the finite DM velocity correction at tree-level is subdominant with respect to the one-loop contribution. Based on the analytic formulae, our numerical studies show that, for a typical choice of model parameters, the DM nuclear recoiling cross section is well below O(10 −50 cm 2 ), which indicates that the DM direct detection signal in this model naturally avoids the present strong experimental limits on the cross section.

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Section: Tree-level Contributions To the Dm-nucleon Scattering At Finmentioning

confidence: 99%

One-loop contribution to dark-matter-nucleon scattering in the pseudo-scalar dark matter model

Azevedo

Duch

Grza̧dkowski

et al. 2019

J. High Energ. Phys.

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show abstract

“…The EOMS scheme has already been successfully applied to study many physical observables such as the magnetic moments [22,[29][30][31], the masses, and sigma terms [21,[32][33][34] of the octet and decuplet baryons, the hyperon vector couplings [35,36], the axial vector charges [37], the pionnucleon scattering [38,39], the nucleon Compton scattering [40], the neutral pion photo production [41], the scattering of pseudoscalar mesons off D=B mesons [42][43][44], the DD Ã scattering [45], and the Ξ cc masses and sigma terms [46,47]. It will be interesting to see how it describes the magnetic moments of the Ξ cc baryons, particularly from the perspective of lattice QCD simulations.…”

Section: Introductionmentioning

confidence: 99%

Magnetic moments of the spin- 1/2 doubly charmed baryons in covariant baryon chiral perturbation theory

2018

Self Cite

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Inspired by the recent discovery of the Ξ þþ cc by the LHCb Collaboration, we study the magnetic moments of the spin-1=2 doubly charmed baryons up to the next-to-leading order in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. There are three low energy constants at this order: a 1 , a 2 , and g a . The latest lattice QCD simulations allow us to fix a combination of a 1 and a 2 , while the axial-vector coupling g a can be determined in three different ways: by fitting to the lattice QCD data, by the quark model, or by the heavy antiquark diquark symmetry. The magnetic moments of the spin-1=2 doubly charmed baryons, Ξ d cc and Ξ s cc , can then be predicted. We compare our results with those obtained in the heavy baryon chiral perturbation theory and other approaches, and point out some inconsistencies between the lattice QCD simulations and the quark model.

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“…with the effective Higgs-nucleon coupling f N 0.3 [85,88,89]. Here the factor (4µ 2 χN v 2 + m 2 2 ) in the denominator represents the possible light h 2 mediator effects [86,87], where v ≈ 220 km/s denotes the typical DM velocity in the Milky Way relative to the Solar system, and the loop fucntion F (t) is defined as follows…”

Section: Dark Matter Direct Detectionmentioning

confidence: 99%

Strong dark matter self-interaction from a stable scalar mediator

Duch

Grza̧dkowski

Huang

2020

J. High Energ. Phys.

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In face of the small-scale structure problems of the collisionless cold dark matter (DM) paradigm, a popular remedy is to introduce a strong DM self-interaction which can be generated nonperturbatively by a MeV-scale light mediator. However, if such the mediator is unstable and decays into SM particles, the model is severely constrained by the DM direct and indirect detection experiments. In the present paper, we study a model of a self-interacting fermionic DM, endowed with a light stable scalar mediator. In this model, the DM relic abundance is dominated by the fermionic DM particle which is generated mainly via the freeze-out of its annihilations to the stable mediator. Since this channel is invisible, the DM indirect detection constraints should be greatly relaxed. Furthermore, the direct detection signals are suppressed to an unobservable level since fermionic DM scatterings with a nucleon appear at one-loop level. By further studying the bounds from the CMB and BBN on the visible channels involving the dark sector, we show that there is a large parameter space which can generate appropriate DM self-interactions at dwarf galaxy scales, while remaining compatible with other experimental constraints.

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Pion–nucleon sigma term revisited in covariant baryon chiral perturbation theory

Cited by 34 publications

References 45 publications

One-loop contribution to dark-matter-nucleon scattering in the pseudo-scalar dark matter model

One-loop contribution to dark-matter-nucleon scattering in the pseudo-scalar dark matter model

Magnetic moments of the spin- 1/2 doubly charmed baryons in covariant baryon chiral perturbation theory

Strong dark matter self-interaction from a stable scalar mediator

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