Non-Standard Physics in Leptonic Decays

Kronfeld, A. S.

doi:10.22323/1.066.0282

Cited by 8 publications

(13 citation statements)

References 11 publications

(19 reference statements)

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“…In 2007, the c → s ν transitions attracted a lot of interest from the point of view of searches for NP, after the disagreement between the lattice evaluations of the decay constant f Ds and experimental extractions thereof at the level of around 4σ. Several different NP scenarios were considered as explanations of that puzzle [15][16][17]. Current agreements between the experimental results and the lattice evaluations offer an opportunity for a derivation of tight constraints on the NP effects in these processes.…”

Section: Introductionmentioning

confidence: 99%

Discerning new physics in charm meson leptonic and semileptonic decays

2015

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Current experimental information on the charm meson decay observables in which the $c\to s\ell\nu_\ell$ transitions occur is well compatible with the Standard Model predictions. Recent precise lattice calculations of the $D_s$ meson decay constant and form factors in $D\to K\ell\nu$ decays offer a possibility to search for the small deviations from the Standard Model predictions in the next generation of the high intensity flavour experiments. We revisit constraints from these processes on the new physics contributions in the effective theory approach. We investigate new physics effects which might appear in the differential distributions for the longitudinally and transversely polarised $K^\ast$ in $D\to K^\ast\ell\nu_\ell$ decays. Present constraints from these observables are rather weak, but could be used to constrain new physics effects in the future. In the case of $D\to K\ell\nu$ we identify observables sensitive on new physics contribution coming from the scalar Wilson coefficient, namely the forward-backward and the transversal muon asymmetries. By allowing that new physics modifies only the second lepton generation but not the first one, we identify allowed region for the differential decay rate for the process $D\to K\mu\nu_\mu$ and find that it is allowed to deviate from the Standard Model prediction by only few percent. The lepton flavour universality violation can be tested in the ratio $R_{\mu/e}(q^2)\equiv \frac{d\Gamma^{(\mu)}}{dq^2}/\frac{d\Gamma^{(e)}}{dq^2}$. If the first lepton generation behaves as in the Standard Model, we find, using current constraint on the scalar Wilson coefficient, that the ratio $R_{\mu/e}(q^2)$ is currently allowed to be within the range $(0.9, 1.2)$, depending on the value of $q^2$

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Section: Introductionmentioning

confidence: 99%

Discerning new physics in charm meson leptonic and semileptonic decays

2015

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“…On the other hand, only a couple of analysis has been done using the Semileptonic and leptonic decays of the D mesons [5,6,7]. In particular, in [5], the lattice calculations of f Ds implied a 3.8σ deviation of the SM prediction over the experimental value.…”

Section: Introductionmentioning

confidence: 99%

“…The discrepancy was alleviated once the form factors were re-evaluated and now it is known with a high level of precision (around 2% error) [9]. In [6] it was suggested the possibility of doing a combined analysis of the semileptonic and leptonic decays of the D mesons but the analysis was not performed. Such analysis was recently done [7] as suggested in [6] now including the updated values of both the semileptonic form factors [3] and leptonic decay constant f Ds [9].…”

Section: Introductionmentioning

confidence: 99%

“…In [6] it was suggested the possibility of doing a combined analysis of the semileptonic and leptonic decays of the D mesons but the analysis was not performed. Such analysis was recently done [7] as suggested in [6] now including the updated values of both the semileptonic form factors [3] and leptonic decay constant f Ds [9]. Because this combination of different BRs it is possible to extract bounds for each relevant Wilson coefficient independently.…”

Section: Introductionmentioning

confidence: 99%

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Two Higgs doublet model and leptoquarks constraints fromDmeson decays

Barranco

Delépine

Macías

et al. 2016

J. Phys. G: Nucl. Part. Phys.

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We use a combined analysis of the semileptonic and leptonic branching ratios of the D mesons to constrain scalar leptoquark interactions and charged higgs-like interactions. For the THDM type II, we found that a low mass 6.3GeV < m H + < 63.1GeV for the charged Higgs is favored at 90% C.L. although at 95% there is still agreement with other constraints. We find for the leptoquark states a more restrictive bound than previous analysis.

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“…Non Standard interactions from a model independent approach had been considered and constrained with D s leptonic decays [19,20], and independently, using semileptonic decays [20,21]. In this work we make a model independent analysis and a model dependent analysis in order to constrain NSIs combining the leptonic and semileptonic decays of the D meson.…”

Section: Introductionmentioning

confidence: 99%

Constraining New Physics with D meson decays

et al. 2014

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Latest Lattice results on $D$ form factors evaluation from first principles show that the standard model (SM) branching ratios prediction for the leptonic $D_s \to \ell \nu_\ell$ decays and the semileptonic SM branching ratios of the $D^0$ and $D^+$ meson decays are in good agreement with the world average experimental measurements. It is possible to disprove New Physics hypothesis or find bounds over several models beyond the SM. Using the observed leptonic and semileptonic branching ratios for the D meson decays, we performed a combined analysis to constrain non standard interactions which mediate the $c\bar{s}\to l\bar{\nu}$ transition. This is done either by a model independent way through the corresponding Wilson coefficients or in a model dependent way by finding the respective bounds over the relevant parameters for some models beyond the standard model. In particular, we obtain bounds for the Two Higgs Doublet Model Type-II and Type III, the Left-Right model, the Minimal Supersymmetric Standard Model with explicit R-Parity violation and Leptoquarks. Finally, we estimate the transverse polarization of the lepton in the $D^0$ decay and we found it can be as high as $P_T=0.23$.Comment: 28 pages, 8 figures, 3 tables. Improved and extended analysis with updated form factors from Lattice QC

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Non-Standard Physics in Leptonic Decays

Cited by 8 publications

References 11 publications

Discerning new physics in charm meson leptonic and semileptonic decays

Discerning new physics in charm meson leptonic and semileptonic decays

Two Higgs doublet model and leptoquarks constraints fromDmeson decays

Constraining New Physics with D meson decays

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