اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدCurrent-independent transition form factors for semileptonic and rare $Dto pi(K)$ decays in the light-front quark model
76
0
0.0
(
0
)
تأليف
Ho-Meoyng Choi
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We investigate the exclusive semileptonic and rare $Dto pi(K)$ decays within the standard model and the light-front quark model (LFQM) constrained by the variational principle for the QCD-motivated effective Hamiltonian. The form factors are obtained in the $q^+=0$ frame and then analytically continue to the physical timelike region. Together with our recent analysis of the current-independent form factors $f_pm(q^2)$ for the semileptonic decays, we present the current-independent tensor form factor $f_T(q^2)$ for the rare decays to make the complete set of hadronic matrix elements regulating the semileptonic and rare $Dtopi(K)$ decays in our LFQM. The tensor form factor $f_T(q^2)$ are obtained from two independent sets $(J^{+perp}_T, J^{+-}_T)$ of the tensor current $J^{mu u}_T$. As in our recent analysis of $f_-(q^2)$, we show that $f_T(q^2)$ obtained from the two different sets of the current components gives the identical result in the valence region of the $q^+=0$ frame without involving the explicit zero modes and the instantaneous contributions. The implications of the zero modes and the instantaneous contributions are also discussed in comparison between the manifestly covariant model and the standard LFQM. In our numerical calculations, we obtain the $q^2$-dependent form factors $(f_pm, f_T)$ for $Dtopi(K)$ and branching ratios for the semileptonic $Dto pi(K)ell u_ell$ ($ell=e,mu$) decays. Our results show in good agreement with the available experimental data as well as other theoretical model predictions.
قيم البحث
اقرأ أيضاً
We report our investigation on the doubly virtual TFFs $F_{{rm P}gamma^*}(Q^2_1,Q^2_2)$ for the ${rm P}togamma^*(q_1)gamma^*(q_2) ;({rm P}=pi^0,eta,eta)$ transitions using the light-front quark model (LFQM). Performing a LF calculation in the exactly
solvable manifestly covariant Bethe-Salpeter (BS) model as the first illustration, we used $q^+_1=0$ frame and found that both LF and manifestly covariant calculations produce exactly the same results for $F_{{rm P}gamma^*}(Q^2_1,Q^2_2)$. This confirms the absence of the LF zero mode in the doubly virtual TFFs. We then mapped this covariant BS model to the standard LFQM using the more phenomenologically accessible Gaussian wave function provided by the LFQM analysis of meson mass spectra. For the numerical analyses of $F_{{rm P}gamma^*}(Q^2_1,Q^2_2)$, we compared our LFQM results with the available experimental data and the perturbative QCD (pQCD) and the vector meson dominance (VMD) model predictions. As $(Q^2_1, Q^2_2)toinfty$, our LFQM result for doubly virtual TFF is consistent with the pQCD prediction, i.e. $F_{{rm P}gamma^*}(Q^2_1, Q^2_2)sim 1/(Q^2_1 + Q^2_2)$, while it differs far from the result of VMD model which behaves $F^{rm VMD}_{{rm P}gamma^*}(Q^2_1, Q^2_2)sim 1/(Q^2_1 Q^2_2)$. Our LFQM prediction for $F_{etagamma^*}(Q^2_1,Q^2_2)$ shows an agreement with the very recent experimental data obtained from the BaBar collaboration for the ranges of $2< Q^2_1, Q^2_1 <60$ GeV$^2$.
We present a recent calculation of the gravitational form factors (GFFs) of proton using the light-front quark-diquark model constructed by the soft-wall AdS/QCD. The four GFFs $~A(Q^2)$ , $B(Q^2)$ , $C(Q^2)$ and $bar{C}(Q^2)$ are calculated in this
model. We also show the pressure and shear distributions of quarks inside the proton. The GFFs, $A(Q^2)$ and $B(Q^2)$ are found to be consistent with the lattice QCD, while the qualitative behavior of the $D$-term form factor is in agreement with the extracted data from the deeply virtual Compton scattering (DVCS) experiments at JLab, the lattice QCD, and the predictions of different phenomenological models.
We investigate the $(pi^0,eta,eta)togamma^*gamma$ transitions both for the spacelike region and the timelike region using the light-front quark model (LFQM). In particular, we present the new direct method to explore the timelike region without resor
ting to mere analytic continuation from the spacelike region to the timelike region. Our direct calculation in timelike region shows the complete agreement not only with the analytic continuation result from the spacelike region but also with the result from the dispersion relation between the real and imaginary parts of the form factor. For the low energy regime, we compare our LFQM results of the transition form factors (TFFs) for the low timelike momentum transfer region and the slope parameters at $q^2=0$ with the recent experimental data from the Dalitz decays of $(pi^0,eta,eta)$. For the high energy regime, we incorporate the QCD factorization in our LFQM to examine the asymptotic behavior of TFFs both for the spacelike region and the timelike region. We compare our results with the available experimental data.
We present a model for the decay $D^+to K^-pi^+pi^+$. The weak interaction part of this reaction is described using the effective weak Hamiltonian in the factorisation approach. Hadronic final state interactions are taken into account through the $Kp
i$ scalar and vector form factors fulfilling analyticity, unitarity and chiral symmetry constraints. Allowing for a global phase difference between the $S$ and $P$ waves of $-65^circ$, the Dalitz plot of the $D^+to K^-pi^+pi^+$ decay, the $Kpi$ invariant mass spectra and the total branching ratio due to $S$-wave interactions are well reproduced.
We predict the $mathcal{V} to mathcal{P} gamma$ decay widths and the $mathcal{V} to mathcal{P} gamma^{*}$ transition form factors, where $mathcal{V}=(rho, omega, K^*, phi)$ and $mathcal{P}= (pi,K, eta,eta^prime)$, using spin-improved holographic ligh
t-front wavefunctions for the mesons. We find excellent agreement with the available data for both the decay widths and the timelike transition form factors extracted from the leptonic conversion decays $mathcal{V} to mathcal{P} l^+ l^-$.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
