Scrutinizing New Physics in Semi-leptonic Bc→J/ψτνB_{c}\rightarrow J/\psi \tau\nu Decay

We perform a global analysis of the $b\to c\tau\nu$ data using the recent lattice results on the $B_c\to J/\psi$ vector and axial-vector form factors. To explore the effects from the tensor operator of new physics beyond the standard model, we determine the tensor form factors by using the non-relativistic QCD (NRQCD) relations between tensor and (axial-)vector form factors. Based on the lattice+NRQCD form factors, we fit the Wilson coefficients and the new physics couplings in $R_2$, $S_1$ and $U_1$ leptoquark models by including the recently measured $R(\Lambda_c)$ and imposing the relaxed constraint $\mathcal B(B_c\to J/\psi)<30\%$ in light of the recent studies on LEP1 data and $B_c$ lifetime. We give predictions for the experimental observables including $R(J/\psi)$, $P_\tau(J/\psi)$, $F_L(J/\psi)$ and $\mathcal A_{FB}(J/\psi)$ as well as their $q^2$ distribution in new physics scenarios/models. Our results suggest that the longitudinal $\tau$ polarization fraction $P_\tau(J/\psi)$ and the forward-backward asymmetry $\mathcal A_{FB}(J/\psi)$ are useful for testing the $R_2$ leptoquark model.Comment: 13 pages, 10 figures and 6 table

Simulation and research of chip-level micromixer with T-type based on ANSYS

A T-shaped chip-scale micromixer with built-in baffles is simulated and investigated based on ANSYS. This paper highlights on a comparative analysis of the effect of different numbers, rows, positions, angles and different Reynolds numbers (Re) of baffles on the mixing efficiency within a chip-scale micromixer. The simulation results demonstrate that: increase in the amount of baffles improved mixing of two fluids; the double rows of baffles significantly improve the mixing efficiency compared with the single rows of baffles; the position of the baffles relocates a certain distance to the outlet, which accelerates mixing of fluids in the chip-scale mixer; the mixing efficiency of baffle angle of 120° is also superior to that of 60°; the Re is between 0.1 and 2, which results in a high mixing efficiency; and the mixing efficiency slowly becomes lower when the Re is between 2 and higher mixing efficiencies with Re values between 0.1 and 2; Re between 2 and 40, the mixing efficiency slowly becomes lower; Re between 40 and 100, the mixing efficiency gradually rises

Unbinned Angular Analysis of B→D∗(Dπ)ℓνℓB\to D^*(D\pi)\ell \nu_\ell and CVRC_{V_R}

International audienceA sensitivity study of the unbinned angular analysis of the $B\to D^*(D\pi)\ell \nu_\ell$ decay is presented. In the analysis, it is shown that the Wilson coefficient of the right-handed vector current, $C_{V_R}$, can be measured to precision of 2-4$\%$ using either the full set of normalised angular observables or the forward-backward asymmetry $A_{FB}$ of the charged lepton in 10 $w$ bins. Such angular measurements are independent of the $V_{cb}$ puzzle

Unbinned Angular Analysis of B→D∗(Dπ)ℓνℓB\to D^*(D\pi)\ell \nu_\ell and CVRC_{V_R}

International audienceA sensitivity study of the unbinned angular analysis of the $B\to D^*(D\pi)\ell \nu_\ell$ decay is presented. In the analysis, it is shown that the Wilson coefficient of the right-handed vector current, $C_{V_R}$, can be measured to precision of 2-4$\%$ using either the full set of normalised angular observables or the forward-backward asymmetry $A_{FB}$ of the charged lepton in 10 $w$ bins. Such angular measurements are independent of the $V_{cb}$ puzzle

Un-binned Angular Analysis of B→D∗ℓνℓB\to D^*\ell \nu_\ell and the Right-handed Current

International audienceIn this article, we perform a sensitivity study of an unbinned angular analysis of the B→D*ℓνℓ decay, including the contributions from the right-handed current. We show that the angular observable can constrain very strongly the right-handed current without the intervention of the yet unsolved Vcb puzzle

Dermatology AI audit - generative AI and classifier weights

&lt;p&gt;PyTorch model weights for trained generative image AI models and retrained version of 2020 SIIM-ISIC winning classifier. Further description available in the preprint "Dissection of medical AI reasoning processes via physician and generative-AI collaboration" (https://doi.org/10.1101/2023.05.12.23289878) and subsequent publication.&lt;/p&gt

New physics in b → sℓℓ anomalies and its implications for the complementary neutral current decays

International audienceWe study the Standard Model and the new physics predictions for the lepton-flavour-universality violating (LFUV) ratios in various b→sℓ+ℓ− channels with scalar, pseudoscalar, vector, axial-vector, and Λ baryon final states, considering both unpolarized and polarized final state hadrons. In order to formulate physical observables, we use the model independent effective Hamiltonian approach and employ the helicity formalism. We provide the explicit expressions of the helicity amplitudes in terms of the Wilson coefficients and the hadronic form factors by using the same kinematical configuration and polarization conventions for all the decay channels. We perform the numerical analysis with new physics scenarios selected from the recent global fits to b→sℓ+ℓ− data, having specific new physics model interpretations. We find that some of the LFUV ratios for these complementary channels in different kinematical regions have high sensitivity to new physics and the future measurements of them in Belle II and LHCb experiments, along with testing new physics/LFUV, can help to distinguish among some of the different new physics possibilities

Revisit to the b→cτνb\to c\tau\nu transition: In and beyond the SM

International audienceWe perform an analysis of the b→cτν data, including R(D(⁎)) , R(J/ψ) , Pτ(D⁎) and FLD⁎ , within and beyond the Standard Model (SM). We fit the B→D(⁎) hadronic form factors in the HQET parametrization to the lattice and the light-cone sum rule (LCSR) results, applying the general strong unitarity bounds corresponding to JP=1− , 1+ , 0− and 0+ . Using the obtained HQET relations between helicity amplitudes, we give the strong unitarity bounds on individual helicity amplitudes, which can be used in the BGL fits. Using the fitted form factors and taking into account the most recent Belle measurement of R(D(⁎)) we investigate the model-independent and the leptoquark model explanations of the b→cτν anomalies. Specifically, we consider the one-operator, the two-operator new physics (NP) scenarios and the NP models with a single R2 , S1 or U1 leptoquark which is supposed to be able to address the b→cτν anomalies, and our results show that the R2 leptoquark model is in tension with the limit B(Bc→τν)<10% . Furthermore, we give predictions for the various observables in the SM and the NP scenarios/leptoquark models based on the present form factor study and the analysis of NP