Zemach moments of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>3</mml:mn></mml:mmultiscripts></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi mathvariant="normal">He</mml:mi><mml:mprescripts /><mml:none /><mml:mn>4</mml:mn></mml:mmultiscripts></mml:mrow></mml:math>

Sick, I.

doi:10.1103/physrevc.90.064002

Cited by 42 publications

(70 citation statements)

References 26 publications

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“…This mean-square radius corresponds to the distribution of the centers of the nucleons and, after correcting for the nucleon size, this leads to an experimental value of β 2 = 13.7 GeV −2 [44]. Due to the form factor, the optical potential in Eq.…”

Section: A the η 3 He Interactionmentioning

confidence: 99%

Determination of the ηHe3 threshold structure from the low energy pd→ηHe
Xie
¹
,
Wu
²
,
Oset
³

et al. 2017
Phys. Rev. C
38
4
30
0
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We analyze the data on cross sections and asymmetries for the pd(dp) → η 3 He reaction close to threshold and look for bound states of the η 3 He system. Rather than parameterizing the scattering matrix, as is usually done, we develop a framework in which the η 3 He optical potential is the key ingredient, and its strength, together with some production parameters, are fitted to the available experimental data. The relationship of the scattering matrix to the optical potential is established using the Bethe-Salpeter equation and the η 3 He loop function incorporates the range of the interaction given by the empirical 3 He density. We find a local Breit Wigner form of the η 3 He amplitude T below threshold with a clear peak in |T | 2 , which corresponds to an η 3 He binding of about 0.3 MeV and a width of about 3 MeV. By fitting the potential we can also evaluate the η 3 He scattering length, including its sign, thus resolving the ambiguity in the former analyses.

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Section: A the η 3 He Interactionmentioning

confidence: 99%

Determination of the ηHe3 threshold structure from the low energy pd→ηHe
Xie
¹
,
Wu
²
,
Oset
³

et al. 2017
Phys. Rev. C
38
4
30
0
View full text Add to dashboard Cite

show abstract

“…To resolve the proton radius puzzle, the CREMA collaboration at Paul Scherrer Institute have performed new measurements of the Lamb shifts in other light muonic atoms (μD, μ 3 He + and μ 4 He + ) [3], with results yet to be published. These measurements aim to extract the nuclear charge radii with extremely high accuracy, which will be benchmarked with current and future spectroscopy measurements in electronic atoms [4][5][6] and electron-nucleus scattering data [7,8].…”

Section: Introductionmentioning

confidence: 99%

Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

Chen¹,

Hernandez²,

Dinur³

et al. 2016

EPJ Web of Conferences

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“…from (12), in terms of ρ U h , for easier comparison later with other channels, and obtain the result in Figure 5. One sees that in the expected range of m U around 20 MeV, ρ U h is found to have value of order 10 −1 .…”

Section: The G − and Lamb Shift Anomaliesmentioning

confidence: 98%

“…In (12) then, only the coefficient m T depends on the species, this being the mass of the heaviest generation of that species, thus for the U -type quarks, m T = m t , the mass of the top quark, and for the charged leptons m T = m τ , the mass of the tau lepton. According to previous arguments then, the couplings of U to quarks and leptons differ from (12) only by being multiplied by the mixing factor ρ U h and by the fact that for the problems at hand the rotating scale-dependent vector α is to be evaluated, by usual prescription, at the scale of the U mass, m U .…”

Section: The G − and Lamb Shift Anomaliesmentioning

confidence: 99%

Accommodating three low-scale anomalies (g − 2, Lamb shift, and Atomki) in the framed Standard Model

Bordes

Hong-Mo

Tsun

2019

Int. J. Mod. Phys. A

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The framed standard model (FSM) predicts a 0 + boson with mass around 20 MeV in the "hidden sector", which mixes at tree level with the standard Higgs h W and hence acquires small couplings to quarks and leptons which can be calculated in the FSM apart from the mixing parameter ρ U h . The exchange of this mixed state U will contribute to g − 2 and to the Lamb shift. By adjusting ρ U h alone, it is found that the FSM can satisfy all present experimental bounds on the g − 2 and Lamb shift anomalies for µ and e, and for the latter for both hydrogen and deuterium.The FSM predicts also a 1 − boson in the "hidden sector" with a mass of 17 MeV, that is, right on top of the Atomki anomaly X. This mixes with the photon at 1-loop level and couples thereby like a dark photon to quarks and leptons. It is however a compound state and is thought likely to possess additional compound couplings to hadrons. By adjusting the mixing parameter and the X's compound coupling to nucleons, the FSM can reproduce the 1 production rate of the X in beryllium decay as well as satisfy all the bounds on X listed so far in the literature.The above two results are consistent in that the U , being 0 + , does not contribute to the Atomki anomaly if parity and angular momentum are conserved, while X, though contributing to g − 2 and Lamb shift, has smaller couplings than U and can, at first instance, be neglected there.Thus, despite the tentative nature of the 3 anomalies in experiment on the one hand and of the FSM as theory on the other, the accommodation of the former in the latter has strengthened the credibility of both. Indeed, if this FSM interpretation were correct, it would change the whole aspect of the anomalies from just curiosities to windows into a vast hitherto hidden sector comprising at least in part the dark matter which makes up the bulk of our universe.The results [A] and [B] lack statistical significance while [C] needs to be independently confirmed. But if they are real, then the consequence is highly significant, being suggestive of new physics outside the standard model framework.It has been suggested that [A] and [B] are explainable by a new scalar boson (say U ) of low mass while [C] points to a new (perhaps spin 1) boson (say X) of mass around 17 MeV. The fact that the effects [A]-[C] are all small and no hints of U and X are seen anywhere else means that these new bosons must have rather unusual properties and small couplings to ordinary matter. The question is then raised as to the theoretical origin of these particles U and X which would lie outside the standard model framework. Are they just isolated phenomena or is there a whole new class of particles hitherto unknown to us which interact but little with the particles we know, and of which both U and X are but examples as tips of an iceberg?To address these questions in general terms, the framed standard model (FSM) seems rather well placed. It predicts, among other things, a cluster of boson states, some scalars H light and some vectors G light , all with masses ar...

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Zemach moments ofHe3andHe4

Cited by 42 publications

References 26 publications

Determination of the ηHe3 threshold structure from the low energy pd→ηHe
Xie
¹
,
Wu
²
,
Oset
³

et al. 2017
Phys. Rev. C
38
4
30
0
View full text Add to dashboard Cite

Determination of the ηHe3 threshold structure from the low energy pd→ηHe
Xie
¹
,
Wu
²
,
Oset
³

et al. 2017
Phys. Rev. C
38
4
30
0
View full text Add to dashboard Cite

Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

Accommodating three low-scale anomalies (g − 2, Lamb shift, and Atomki) in the framed Standard Model

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Zemach moments ofHe3andHe4

Cited by 42 publications

References 26 publications

Determination of the ηHe3 threshold structure from the low energy pd→ηHeXie1, Wu2, Oset3 et al. 2017Phys. Rev. C384300View full textAdd to dashboardCite

Determination of the ηHe3 threshold structure from the low energy pd→ηHeXie1, Wu2, Oset3 et al. 2017Phys. Rev. C384300View full textAdd to dashboardCite

Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

Accommodating three low-scale anomalies (g − 2, Lamb shift, and Atomki) in the framed Standard Model

Contact Info

Product

Resources

About

Determination of the ηHe3 threshold structure from the low energy pd→ηHe
Xie
¹
,
Wu
²
,
Oset
³

et al. 2017
Phys. Rev. C
38
4
30
0
View full text Add to dashboard Cite

Determination of the ηHe3 threshold structure from the low energy pd→ηHe
Xie
¹
,
Wu
²
,
Oset
³

et al. 2017
Phys. Rev. C
38
4
30
0
View full text Add to dashboard Cite