We present a systematic survey of possible short-distance new-physics effects in (semi)leptonic charged- and neutral-current charmed meson decays. Using the Standard Model Effective Field Theory (SMEFT) to analyze the most relevant experimental data at low and high energies, we demonstrate a striking complementarity between charm decays and high invariant mass lepton tails at the LHC. Interestingly enough, high-$p_T$ Drell-Yan data offer competitive constraints on most new physics scenarios. Furthermore, the full set of correlated constraints from $K$, $π$ and $τ$ decays imposed by $SU(2)_L$ gauge invariance is considered. The bounds from $D_{(s)}$ decays, high-$p_T$ lepton tails and $SU(2)_L$ relations chart the space of the SMEFT affecting semi(leptonic) charm flavor transitions.
Non-Standard Physics in Leptonic and Semileptonic Decays of Charmed Mesons
最近对D_s -> 1 nu的分支分数的测量结果与标准模型的预期不一致，标准模型的预期依赖于格点量子色动力学对$f_{D_s}$的计算。本文使用最近的初步测量从CLEO和一个新的初步格QCD结果从这次会议上更新的差异的意义。“f_{D_s}之谜”现在是3.5西格玛，西格玛主要来自实验的统计不确定性。新的物理方案，可以解决这个难题，也将导致非标准振幅介导的半轻子衰变D -> K l nu。本文展示了新的振幅进入微分速率和概述格点量子色动力学计算需要面对最近和即将到来的测量。
We analyze the quasi-two-body charmed $B$ decays $B^{+,0}_{(s)} \to D_{(s)}^* P_2 \to D_{(s)} P_1 P_2$ with $P_{1,2}$ as a pion or kaon. The intermediate processes $B_{(s)} \to D_{(s)}^* P_2 $ are calculated with the factorization-assisted topological-amplitude approach and the resonant effects are calculated with the Breit-Wigner formalism. Taking all p-wave resonance states $ \bar D_{(s)}^*$ into consideration, we present the related branching fractions, calculate the Breit-Wigner-Tail effects, and investigate the flavor $SU(3)$ breaking effects. Most of our branching fractions are consisten…
Analysis of strong decays of charmed mesons $D^*_2(2460)$, $D_0(2560)$, $D_2(2740)$, $D_1(3000)$, $D^*_2(3000)$ and their spin partners $D^*_1(2680)$, $D^*_3(2760)$ and $D^*_0(3000)$
We evaluate the masses and decay constants of the $0^+$ and $1^-$ open-charm $(\bar{c}\bar{d})(us)$ tetraquarks and molecular states from QCD spectral sum rules (QSSR) by using QCD Laplace sum rule (LSR). This method takes into account the stability criteria where the factorized perturbative NLO corrections and the contributions of quark and gluon condensates up to dimension-6 in the OPE are included. We confront our results with the $D^- K^+$ invariant mass recently reported by LHCb from $B^+ \to D^+(D^- K^+)$ decays. We expect that the resonance near the $D^- K^+$ threshold can be originated…
Starting from a general effective Lagrangian for lepton flavor violation (LFV) in quark-lepton transitions, we derive constraints on the effective coefficients from the high-mass tails of the dilepton processes $pp \to \ell_k \ell_l$ (with $k\neq l$). The current (projected) limits derived in this paper from LHC data with $36~\mathrm{fb}^{-1}$ ($3~\mathrm{ab}^{-1}$) can be applied to generic new physics scenarios, including the ones with scalar, vector and tensor effective operators. For purely left-handed operators, we explicitly compare these LHC constraints with the ones derived from flavor…
We employ the flavor SU(3) symmetry to analyze semileptonic decays of anti-triplet charmed baryons ($Λ^{+}_{c},Ξ_{c}^{+,0}$) and find that the experimental data on ${\cal B}(Λ_c\toΛ\ell^+ν_{\ell})$ implies $\mathcal{B}(Ξ_c^0\toΞ^-e^+ν_{e})=(4.10\pm0.46)\%$ and $\mathcal{B}(Ξ_c^0\toΞ^-μ^+ν_μ)= (3.98\pm0.57)\%$. When this prediction is confronted with recent experimental results from Belle collaboration $\mathcal{B}(Ξ_c^0\toΞ^-e^+ν_e)=1.31(04\pm07\pm38)\%$ and $\mathcal{B}(Ξ_c^0\toΞ^-μ^+ν_μ)=1.27(06\pm10\pm 37)\%$, it is found that the SU(3) symmetry is severely broken. We then consider the gene…
In the framework of the Standard Model we present new theoretical predictions for the branching ratios, double and single differential distributions and forward -- backward leptonic asymmetries for the $\bar B_s \to μ^+ μ^- e^+ e^-$ decay. In our consideration we take into account the $ϕ(1020)$ -- resonance contribution; the main contributions of four charmonium resonances : $ψ(3770)$, $ψ(4040)$, $ψ(4160)$ and $ψ(4415)$; $u\bar{u}$ -- resonant contribution from $ρ(770)$ and $ω(782)$; tails contributions from $J/ψ$ and $ψ(2S)$ resonances; non -- resonant contribution of the $b\,\bar{b}$ - pairs…
