Flavor-changing hyperon decays with light invisible bosons

Li, Gang; Su, J.; Tandean, Jusak

doi:10.1103/physrevd.100.075003

“…The search for the FCNC decays of hyperons with missing energy ( / E) carried away by a pair of invisible particles, due to the quark transition s → d / E, can expectedly be realized in the BESIII experiment [11] and is complementary to quests for kaon decays with missing energy. The forthcoming results would likely be informative regarding possible NP affecting this transition [12,13]. The prospects for BESIII pursuing two-body hyperon decays with a massless dark photon being invisibly emitted are comparatively better provided that their branching fractions are not too small.…”

mentioning

confidence: 94%

Searching for dark photons in hyperon decays

Su

¹

,

Tandean

²

2020

Self Cite

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That massless dark photons could exist and have flavor-changing magnetic-dipole couplings to downtype light quarks is an attractive possibility which may be realized in various new-physics scenarios. It is potentially testable not only in kaon processes but also via two-body hyperon decays involving missing energy carried away by the massless dark photon. We explore the latter within a simplified model approach and take into account constraints from the kaon sector. We find that the branching fractions of some of these hyperon modes are allowed to be as high as a few times 10 −4 . Such numbers are likely to be within the sensitivity reaches of ongoing experiments like BESIII and future ones at super charm-tau factories.

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“…The foregoing motivates us in this paper to examine these strangeness-changing (jΔSj ¼ 1) hyperon decays with missing energy in the contexts of relatively simple NP models. It also serves to complement earlier modelindependent analyses in which the missing energy was assumed to be carried away by an invisible pair of spin-1=2 particles [6] or spinless ones [7]. Within a specific model the parameters determining the strength of the s → dE operators often enter other observables, which may be well constrained by their respective data.…”

Section: Introductionmentioning

confidence: 92%

“…As demonstrated in Refs. [6,7], the constraints from K → E and K → ππ 0 E are sufficiently loose to allow these hyperon modes to have branching fractions greatly exceeding their SM predictions and within the proposed sensitivity reach of BESIII for these processes [11]. Its search for them may then be expected to yield valuable information regarding NP which could be lurking in the underlying quark transition.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, as pointed out in Refs. [6,7], the impact of NP could still be large through operators having exclusively parity-odd ds quark bilinears. The reason is that these operators do not participate directly in K → πE, hence not restricted by their data, and are instead subject to restraints from the channels with no or two pions, namely K → E and K → ππ 0 E, which at the moment have comparatively loose empirical bounds [5,[8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…The effective s → dE operators governing all of the aforementioned kaon modes affect their baryon counterparts as well and consequently may also be testable in the FCNC decays of hyperons with missing energy [6,7], on which there has been no measurement yet [5]. It is therefore of keen interest that there has recently been a proposal to pursue them in the BESIII experiment [11], which is currently in operation and has acquired an ample hyperon dataset [12].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Exploring leptoquark effects in hyperon and kaon decays with missing energy

Su

¹

,

Tandean

²

2020

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We entertain the possibility that scalar leptoquarks (LQs) generate consequential effects on the strangeness-changing decays of hyperons and kaons involving missing energy carried away by a pair of invisible fermions. Although such processes have suppressed rates in the standard model (SM), they could get significant enhancement in the presence of the LQs. In order to respect the available data on the kaon modes K → πνν and increase the rates of the hyperon decays substantially at the same time, two different scalar LQs are needed. If the LQs have Yukawa couplings solely to SM fermions, we find that the hyperon rates cannot attain values within the reach of ongoing or near-future experiments because of the combined constraints from the measurements on kaon mixing and lepton-flavor-violating processes. However, if we include light right-handed neutrinos in the LQ interactions, their contributions can evade the leading restrictions and translate into hyperon rates which may be big enough to be probed by upcoming searches. Thus, these hyperon modes could provide a new avenue for seeking sterile neutrinos.

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New physics in s → d semileptonic transitions: rare hyperon vs. kaon decays

Geng

¹

,

Camalich

²

,

Shi

³

2022

J. High Energ. Phys.

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We investigate the potential of rare hyperon decays to probe the short distance structure in the $$ s\to dv\overline{v} $$ s → dv v ¯ and s → dℓ+ℓ− transitions. Hyperon decays into neutrinos $$ \left({B}_1\to {B}_2v\overline{v}\right) $$ B 1 → B 2 v v ¯ can be reliably predicted by using form factors determined in baryon chiral perturbation theory. Their decay rates are sensitive to different short-distance operators, as compared to their kaon counterparts, and the corresponding branching fractions are in the range of 10−14 ∼ 10−13 in the standard model. In the context of the low-energy effective theory, we find that the anticipated BESIII measurements of the $$ {B}_1\to {B}_2v\overline{v} $$ B 1 → B 2 v v ¯ decays would lead to constraints on new physics in the purely axial vector $$ \overline{d}{\gamma}_{\mu }{\gamma}_5s $$ d ¯ γ μ γ 5 s current that are stronger than the present limits from their kaon siblings $$ K\to \pi \pi v\overline{v} $$ K → ππv v ¯ . On the other hand, although hyperon decays into charged leptons are dominated by long-distance hadronic contributions, angular observable such as the leptonic forward-backward asymmetry is sensitive to the interference between long- and short-distance contributions. We discuss the sensitivity to new physics of a potential measurement of this observable in comparison with observables in the kaon decays KL→ μ+μ− and K+→ π+μ+μ−. We conclude that the current kaon bounds are a few orders of magnitude better than those that could be obtained from Σ+→ pμ+μ− except for two scenarios with new physics in the $$ \left(\overline{d}{\gamma}^{\mu }s\right)\left(\overline{\mathrm{\ell}}{\gamma}_{\mu }{\gamma}_5\mathrm{\ell}\right) $$ d ¯ γ μ s ℓ ¯ γ μ γ 5 ℓ and $$ \left(\overline{d}{\gamma}^{\mu }{\gamma}_5s\right)\left(\overline{\mathrm{\ell}}{\gamma}_{\mu}\mathrm{\ell}\right) $$ d ¯ γ μ γ 5 s ℓ ¯ γ μ ℓ currents. Finally, we point out that the loop effects from renormalization group evolution are important in this context, when relating the low-energy effective field theory to new physics models in the UV.

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Flavor-changing hyperon decays with light invisible bosons

Cited by 10 publications

References 46 publications

Searching for dark photons in hyperon decays

Searching for dark photons in hyperon decays

Exploring leptoquark effects in hyperon and kaon decays with missing energy

New physics in s → d semileptonic transitions: rare hyperon vs. kaon decays

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