اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدEvaluating decay Rates and Asymmetries of $Lambda_b$ into Light Baryons in LFQM
44
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
In this work we calculate the branching ratios of semi-leptonic and non-leptonic decays of $Lambda_b$ into light baryons ($p$ and $Lambda$), as well as the measurable asymmetries which appear in the processes, in the light front quark model (LFQM). In the calculation, we adopt the diquark picture and discuss the justifiability of applying the picture in our case. Our result on the branching ratio of $Lambda_btoLambda+J/psi$ is in good agreement with data. More predictions are made in the same model and the results will be tested in the future experiments which will be conducted at LHCb and even ILC.
قيم البحث
اقرأ أيضاً
The leading electromagnetic (e.m.) and strong isospin-breaking corrections to the $pi^+ to mu^+ u[gamma]$ and $K^+ to mu^+ u[gamma]$ leptonic decay rates are evaluated for the first time on the lattice. The results are obtained using gauge ensemble
s produced by the European Twisted Mass Collaboration with $N_f = 2 + 1 + 1$ dynamical quarks. The relative leading-order e.m.~and strong isospin-breaking corrections to the decay rates are 1.53(19)% for $pi_{mu 2}$ decays and 0.24(10)% for $K_{mu 2}$ decays. Using the experimental values of the $pi_{mu 2}$ and $K_{mu 2}$ decay rates and updated lattice QCD results for the pion and kaon decay constants in isosymmetric QCD, we find that the Cabibbo-Kobayashi-Maskawa matrix element $ | V_{us}| = 0.22538(46)$, reducing by a factor of about $1.8$ the corresponding uncertainty in the Particle Data Group review. Our calculation of $|V_{us}|$ allows also an accurate determination of the first-row CKM unitarity relation $| V_{ud}|^2 + | V_{us}|^2 + | V_{ub}|^2 = 0.99988(46)$. Theoretical developments in this paper include a detailed discussion of how QCD can be defined in the full QCD+QED theory and an improved renormalisation procedure in which the bare lattice operators are renormalised non-perturbatively into the (modified) Regularization Independent Momentum subtraction scheme and subsequently matched perturbatively at $O(alpha_{em}alpha_s(M_W))$ into the W-regularisation scheme appropriate for these calculations.
We introduce a classification number $n$ which describes the baryon mass information in a fuzzy manner. According to $n$ and $J^p$ of baryons, we put all known light baryons in a simple table in which some baryons with same ($n$, $J^p$) are classifie
d as members of known octets or decuplets. Meanwhile, we predict two new possible octets.
The helicity formalism applied to the radiative decay $Lambda_b^0to pK^-gamma$ is presented for the first time in this paper. The aim is to provide the necessary formalism to be able to resolve the resonant $pK^-$ structures at the photon pole by mea
ns of an amplitude analysis. Experimental effects, such as resolution, are also discussed.
We study the non-leptonic two-body weak decays of $Lambda_b^0 to p M$ with $ M=(pi^-,K^-)$ and $(rho^-,K^{*-})$ in the light-front quark model under the generalized factorization ansatz. By considering the Fermi statistic between quarks and determini
ng spin-flavor structures in baryons, we calculate the branching ratios (${cal B}$s) and CP-violating rate asymmetries ($mathcal{A}_{CP}$s) in the decays. Explicitly, we find that ${cal B}( Lambda_b^0 to p pi^- ,pK^-)=(4.18pm0.15pm0.30, 5.76pm0.88pm0.23)times10^{-6}$ and ${mathcal{A}_{CP}}( Lambda_b^0 to p pi^- ,,pK^-)=(-3.60pm0.14pm0.14, 6.36pm0.21pm0.18)%$ in comparison with the data of ${cal B}( Lambda_b^0 to p pi^- ,pK^-)=(4.5pm0.8, 5.4pm1.0)times10^{-6}$ and ${mathcal{A}_{CP}}( Lambda_b^0 to p pi^- ,pK^-)=(-2.5pm 2.9, -2.5pm2.2)%$ given by the Particle Data Group, respectively. We also predict that ${cal B}( Lambda_b^0 to p rho^-,pK^{*-} )=(12.13pm3.27pm0.91, 2.58pm0.87pm0.13)times 10^{-6}$ and ${mathcal{A}_{CP}}( Lambda_b^0 to p rho^-,pK^{*-} )=(-3.32pm0.00pm0.14,19.25pm0.00pm0.80)%$, which could be observed by the experiments at LHCb.
Experimental data on $ R(D^{(*)}) $, $ R(K^{(*)}) $ and $ R(J/psi) $, provided by different collaborations, show sizable deviations from the SM predictions. To describe these anomalies many new physics scenarios have been proposed. One of them is lep
toquark model with introducing the vector and scalar leptoquarks coupling simultaneously to the quarks and leptons. To look for similar possible anomalies in baryonic sector, we investigate the effects of a vector leptoquark $U_3 (3,3, frac{2}{3})$ on various physical quantities related to the tree-level $ Lambda_b rightarrow Lambda_c ell ~ overline{ u}_ell$ decays ($ ell=mu, ~tau $), which proceed via $ b rightarrow c~ell ~ overline{ u}_ell$ transitions at quark level. We calculate the differential branching ratio, forward-backward asymmetry and longitudinal polarizations of lepton and $Lambda_{c}$ baryon at $ mu $ and $ tau $ lepton channels in leptoquark model and compare their behavior with respect to $ q^2 $ with the predictions of the standard model (SM). In the calculations we use the form factors calculated in full QCD as the main inputs and take into account all the errors coming from the form factors and model parameters. It is observed that ........
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
