scholarly journals Sum rules for leading vector form factors in hyperon semileptonic decays

2017 ◽  
Vol 95 (7) ◽  
Author(s):  
Rubén Flores-Mendieta ◽  
Roberto Padrón-Stevens
Keyword(s):  
Sum Rules ◽  
Form Factors ◽  
Semileptonic Decays ◽  
Vector Form

The axial vector form factors and electroproduction sum rules

1966 ◽  
Vol 44 (2) ◽  
pp. 427-439 ◽  
Author(s):  
G. Furlan ◽  
R. Jengo ◽  
E. Remiddi
Keyword(s):  
Sum Rules ◽  
Axial Vector ◽  
Form Factors ◽  
Vector Form

scholarly journals Semileptonic Decays ofB(Bs)to Light Tensor Mesons

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Reza Khosravi ◽  
S. Sadeghi
Keyword(s):  
Sum Rules ◽  
Form Factors ◽  
Semileptonic Decays ◽  
Branching Ratios ◽  
Quark Condensate ◽  
Qcd Sum Rules ◽  
Frame Work ◽  
The Continuum

The semileptonicBs(B)→K2⁎(a2,f2)lν,l=τ,μ, transitions are investigated in the frame work of the three-point QCD sum rules. Considering the quark condensate contributions, the relevant form factors of these transitions are estimated. The branching ratios of these channel modes are also calculated at different values of the continuum thresholds of the tensor mesons and compared with the obtained data for other approaches.

scholarly journals A new angle on an old problem: helicity approach to neutron beta decay in the Standard Model

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Stefan Groote ◽  
Jürgen G. Körner ◽  
Blaženka Melić
Keyword(s):  
Axial Vector ◽  
Form Factors ◽  
Semileptonic Decays ◽  
The Other ◽  
Vector Form ◽  
Neutron Beta Decay ◽  
Heavy Baryons ◽  
The Standard Model ◽  
The One ◽  
Three Body

AbstractWe elaborate on the dichotomy between the description of the semileptonic decays of heavy hadrons on the one hand and the semileptonic decays of light hadrons such as neutron $$\beta $$β decays on the other hand. For example, almost without exception the semileptonic decays of heavy baryons are described in cascade fashion as a sequence of two two-body decays $$B_1 \rightarrow B_2 + W_\mathrm{off-shell}$$B1→B2+Woff-shell and $$W_{\mathrm{off-shell}} \rightarrow \ell + \nu _\ell $$Woff-shell→ℓ+νℓ whereas neutron $$\beta $$β decays are analyzed as true three-body decays $$n \rightarrow p + e^- +{\bar{\nu }}_e$$n→p+e-+ν¯e. Within the cascade approach it is possible to define a set of seven angular observables for polarized neutron $$\beta $$β decays as well as the longitudinal, transverse and normal polarization of the decay electron. We determine the dependence of the observables on the usual vector and axial vector form factors. In order to be able to assess the importance of recoil corrections we expand the rate and the $$q^2$$q2 averages of the observables up to NLO and NNLO in the recoil parameter $$\delta =(M_n-M_p)/(M_n+M_p)= 0.689\cdot 10^{-3}$$δ=(Mn-Mp)/(Mn+Mp)=0.689·10-3. Remarkably, we find that the rate and three of the four parity conserving polarization observables that we analyze are protected from NLO recoil corrections when the second class current contributions are set to zero.

scholarly journals D → a1, f1 transition form factors and semileptonic decays via 3-point QCD sum rules

2016 ◽  
Vol 31 (20n21) ◽  
pp. 1650116 ◽  
Author(s):  
Yabing Zuo ◽  
Yue Hu ◽  
Linlin He ◽  
Wei Yang ◽  
Yan Chen ◽  
...  
Keyword(s):  
Sum Rules ◽  
Axial Vector ◽  
Form Factors ◽  
Semileptonic Decays ◽  
Branching Ratios ◽  
Transition Form ◽  
Vector Mesons ◽  
Qcd Sum Rules ◽  
The Future ◽  
Spin Triplet

By using the 3-point QCD sum rules, we calculate the transition form factors of [Formula: see text] decays into the spin triplet axial vector mesons [Formula: see text], [Formula: see text], [Formula: see text]. In the calculations, we consider the quark contents of each meson in detail. In view of the fact that the isospin of [Formula: see text] is one, we calculate the [Formula: see text] and [Formula: see text] transition form factors separately. In the case of [Formula: see text], [Formula: see text], the mixing between light flavor [Formula: see text] singlet and octet is taken into account. Based on the form factors obtained here, we give predictions for the branching ratios of relevant semileptonic decays, which can be tested in the future experiments.

scholarly journals Light-cone sum rules for proton decay

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Ulrich Haisch ◽  
Amando Hala
Keyword(s):  
Lattice Qcd ◽  
Light Cone ◽  
Sum Rules ◽  
State Of The Art ◽  
Form Factors ◽  
Baryon Number ◽  
Proton Decay ◽  
Matrix Elements ◽  
Decay Channels ◽  
Systematic Uncertainties

Abstract We estimate the form factors that parametrise the hadronic matrix elements of proton-to-pion transitions with the help of light-cone sum rules. These form factors are relevant for semi-leptonic proton decay channels induced by baryon-number violating dimension-six operators, as typically studied in the context of grand unified theories. We calculate the form factors in a kinematical regime where the momentum transfer from the proton to the pion is space-like and extrapolate our final results to the regime that is relevant for proton decay. In this way, we obtain estimates for the form factors that show agreement with the state-of-the-art calculations in lattice QCD, if systematic uncertainties are taken into account. Our work is a first step towards calculating more involved proton decay channels where lattice QCD results are not available at present.

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