scholarly journals Study of Rare Semileptonic Bc+→D+νν- Decay in the Light-Cone Quark Model

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Nisha Dhiman ◽  
Harleen Dahiya
Keyword(s):  
Quark Model ◽  
Light Cone ◽  
Continuation Method ◽  
Branching Ratio ◽  
Form Factors ◽  
Analytic Solutions ◽  
Model Predictions ◽  
Timelike Region ◽  
Mixing Matrix ◽  
Near Future

We study the exclusive semileptonic rare Bc+→D+νν¯ decay in the framework of light-cone quark model. The transition form factors f+(q2) and fT(q2) are evaluated in the timelike region using the analytic continuation method in q+=0 frame. The analytic solutions of these form factors are compared with the results obtained from the double pole parametric form. The branching ratio for Bc+→D+νν¯ decay is calculated and compared with the other theoretical model predictions. The predicted results in this model can be tested at the LHCb experiments in near future which will help in testing the unitarity of CKM quark mixing matrix, thus providing an insight into the phenomenon of CP violation.

RADIATIVE DECAYS OF HEAVY MESON IN THE LIGHT CONE QCD SUM RULE

2000 ◽  
Vol 15 (04) ◽  
pp. 601-608
Author(s):  
H. ROUTH
Keyword(s):  
Light Cone ◽  
D Mesons ◽  
Branching Ratio ◽  
Form Factors ◽  
Heavy Meson ◽  
Radiative Decays ◽  
Long Distance ◽  
Sum Rule ◽  
Penguin Contribution ◽  
Decay Modes

The long-distance contribution of heavy B and D mesons are calculated in the light cone QCD sum rule. Here I have discussed both the parity conserving and parity violating form factors in the radiative decays of B and D mesons e.g. B*, B**, [Formula: see text], D*, D** and [Formula: see text] mesons. I have studied the decay of type P → Vγ and estimated the light cone QCD sum rule form factors and the branching ratio for various decay modes of B and D mesons. Although the short-distance electromagnetic Penguin contribution is the dominant contribution in the P → Vγ decay, it is also necessary to take into account the long distance contribution for completeness of study of the decays discussed in the text.

scholarly journals Semileptonic decay of $$\varOmega _c^0 \rightarrow \varXi ^- l^+ \nu _l$$ from light-cone sum rules

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Hui-Hui Duan ◽  
Yong-Lu Liu ◽  
Ming-Qiu Huang
Keyword(s):  
Decay Width ◽  
Light Cone ◽  
Sum Rules ◽  
Semileptonic Decay ◽  
Decay Channel ◽  
Branching Ratio ◽  
Form Factors ◽  
Weak Decay ◽  
Decay Process ◽  
Sum Rule

AbstractThe weak decay process of $$\varOmega _c$$ Ω c to $$\varXi $$ Ξ is calculated in the method of QCD light-cone sum rule. The decay width of $$\varOmega _c^0 \rightarrow \varXi ^- l^+ \nu _l$$ Ω c 0 → Ξ - l + ν l and its decay branching ratio are also calculated with the form factors from this work’s calculation. To the twist-6 distribution amplitudes, the form factors $$f_1=0.66\pm 0.02, f_2=-0.76\pm 0.03, g_1=0.06\pm 0.01$$ f 1 = 0.66 ± 0.02 , f 2 = - 0.76 ± 0.03 , g 1 = 0.06 ± 0.01 and $$g_2=-0.44\pm 0.01$$ g 2 = - 0.44 ± 0.01 are given at zero recoil point. The result of the semileptonic decay width of $$\varOmega _c^0 \rightarrow \varXi ^-l^+\nu _l$$ Ω c 0 → Ξ - l + ν l is $$\varGamma =(7.51\pm 0.36)\times 10^{-15}~\mathrm{{GeV}}$$ Γ = ( 7.51 ± 0.36 ) × 10 - 15 GeV , and the prediction of the decay branching ratio $$Br(\varOmega _c^0\rightarrow \varXi ^-l^+\nu _l)=(3.06\pm 0.15)\times 10^{-3}$$ B r ( Ω c 0 → Ξ - l + ν l ) = ( 3.06 ± 0.15 ) × 10 - 3 . These results fit well with other works, and the decay width and branching ratio are improved. This not too small branching ratio gives a good direction to explore this decay channel in the future experiments.

scholarly journals Charged and neutral $$ {\overline{B}}_{u,d,s} $$ → γ form factors from light cone sum rules at NLO

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Tadeusz Janowski ◽  
Ben Pullin ◽  
Roman Zwicky
Keyword(s):  
Light Cone ◽  
Correlation Matrix ◽  
Sum Rules ◽  
Branching Ratio ◽  
Form Factors ◽  
Distribution Amplitude ◽  
Amplitude Parameter ◽  
Multiple Polylogarithms ◽  
Supplementary Material ◽  
Inverse Moment

Abstract We present the first analytic $$ \mathcal{O}\left({\alpha}_s\right) $$ O α s -computation at twist-1,2 of the $$ {\overline{B}}_{u,d,s} $$ B ¯ u , d , s → γ form factors within the framework of sum rules on the light-cone. These form factors describe the charged decay $$ {\overline{B}}_u\to \gamma {\mathrm{\ell}}^{-}\overline{v} $$ B ¯ u → γ ℓ − v ¯ , contribute to the flavour changing neutral currents $$ {\overline{B}}_{d,s}\to \gamma {\mathrm{\ell}}^{+}{\mathrm{\ell}}^{-} $$ B ¯ d , s → γ ℓ + ℓ − and serve as inputs to more complicated processes. We provide a fit in terms of a z-expansion with correlation matrix and extrapolate the form factors to the kinematic endpoint by using the gBB*γ couplings as a constraint. Analytic results are available in terms of multiple polylogarithms in the supplementary material. We give binned predictions for the $$ {\overline{B}}_u\to \gamma {\mathrm{\ell}}^{-}\overline{v} $$ B ¯ u → γ ℓ − v ¯ branching ratio along with the associated correlation matrix. By comparing with three SCET-computations we extract the inverse moment B-meson distribution amplitude parameter λB = 360(110) MeV. The uncertainty thereof could be improved by a more dedicated analysis. In passing, we extend the photon distribution amplitude to include quark mass corrections with a prescription for the magnetic vacuum susceptibility, χq, compatible with the twist-expansion. The values χq = 3.21(15) GeV−2 and χs = 3.79(17) GeV−2 are obtained.

scholarly journals Impact of Scalar Leptoquarks on Heavy Baryonic Decays

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
K. Azizi ◽  
A. T. Olgun ◽  
Z. Tavukoğlu
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Lattice Qcd ◽  
Light Cone ◽  
Branching Ratio ◽  
Form Factors ◽  
Full Theory ◽  
The Standard Model ◽  
The Impact ◽  
Scalar Leptoquarks

We present a study on the impact of scalar leptoquarks on the semileptonic decays of Λb, Σb, and Ξb. To this end, we calculate the differential branching ratio and lepton forward-backward asymmetry defining the processes Λb→Λl+l-, Σb→Σl+l-, and Ξb→Ξl+l-, with l being μ or τ, using the form factors calculated via light cone QCD in full theory. In calculations, the errors of form factors are taken into account. We compare the results obtained in leptoquark model with those of the standard model as well as the existing lattice QCD predictions and experimental data.

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