QCD sum rules analysis of weak decays of doubly heavy baryons: the $$b\rightarrow c$$ processes

A comprehensive study of $$b\rightarrow c$$ b → c weak decays of doubly heavy baryons is presented in this paper. The transition form factors as well as the pole residues of the initial and final states are respectively obtained by investigating the three-point and two-point correlation functions in QCD sum rules. Contributions from up to dimension-6 operators are respectively considered for the two-point and three-point correlation functions. The obtained form factors are then applied to a phenomenological analysis of semi-leptonic decays.

The study of doubly charmed pentaquark $$c c {\bar{q}}qq$$ with the SU(3) symmetry

We study the masses and lifetimes of doubly charmed pentaquark $$P_{cc{\bar{q}}qq}(q=u,d,s)$$ P c c q ¯ q q ( q = u , d , s ) primarily. The operation of masses carried out by the doubly heavy triquark-diquark model, whose results suggests the existence of stable states $$cc{\bar{s}} ud$$ c c s ¯ u d with the parity $$J^P=\frac{1}{2}^-$$ J P = 1 2 - . The roughly calculation about lifetimes show the short magnitudes, $$(4.65^{+0.71}_{-0.55})\times 10^{-13}s $$ ( 4 . 65 - 0.55 + 0.71 ) × 10 - 13 s for the parity $$J^P=\frac{1}{2}^-$$ J P = 1 2 - and $$(0.93^{+0.14}_{-0.11})\times 10^{-12} s $$ ( 0 . 93 - 0.11 + 0.14 ) × 10 - 12 s for $$J^P=\frac{3}{2}^-$$ J P = 3 2 - . Since the pentaquark $$cc{\bar{s}} ud$$ c c s ¯ u d is interpreted as the stable bound states against strong decays, then we will focus on the production and possible decay channels of the pentaquark in the next step, the study would be fairly valuable supports for future experiments. For completeness, we systematically studied the production from $$\Omega _{ccc}$$ Ω ccc and the decay modes in the framework SU(3) flavor symmetry, including the processes of semi-leptonic and two body non-leptonic decays. Synthetically, we make a collection of the golden channels.

Flavor SU(3) in Cabibbo-favored D-meson decays

Model-independent description of nonleptonic decays of charmed mesons is a challenging task due to large nonperturbative effects of strong interactions on the transition amplitudes. We discuss the equivalence of two different flavor-SU(3)-based descriptions of Cabibbo-favored non-leptonic decays of charmed mesons to two-pseudoscalars final states including the η and η′ mesons.

QED factorization of two-body non-leptonic and semi-leptonic B to charm decays

The QCD×QED factorization is studied for two-body non-leptonic and semi-leptonic B decays with heavy-light final states. These non-leptonic decays, like $$ {\overline{B}}_{(s)}^0\to {D}_{(s)}^{+}{\pi}^{-} $$ B ¯ s 0 → D s + π − and $$ {\overline{B}}_d^0\to {D}^{+}{K}^{-} $$ B ¯ d 0 → D + K − , are among the theoretically cleanest non-leptonic decays as penguin loops do not contribute and colour-suppressed tree amplitudes are suppressed in the heavy-quark limit or even completely absent. Advancing the theoretical calculations of such decays requires therefore also a careful analysis of QED effects. Including QED effects does not alter the general structure of factorization which is analogous for both semi-leptonic and non-leptonic decays. For the latter, we express our result as a correction of the tree amplitude coefficient a1. At the amplitude level, we find QED effects at the sub-percent level, which is of the same order as the QCD uncertainty. We discuss the phenomenological implications of adding QED effects in light of discrepancies observed between theory and experimental data, for ratios of non-leptonic over semi-leptonic decay rates. At the level of the rate, ultrasoft photon effects can produce a correction up to a few percent, requiring a careful treatment of such effects in the experimental analyses.

B-hadron production in NNLO QCD: application to LHC t$$ \overline{t} $$ events with leptonic decays

We calculate, for the first time, the NNLO QCD corrections to identified heavy hadron production at hadron colliders. The calculation is based on a flexible numeric framework which allows the calculation of any distribution of a single identified heavy hadron plus jets and non-QCD particles. As a first application we provide NNLO QCD predictions for several differential distributions of B hadrons in t$$ \overline{t} $$ t ¯ events at the LHC. Among others, these predictions are needed for the precise determination of the top quark mass. The extension of our results to other processes, like open or associated B and charm production is straightforward. We also explore the prospects for extracting heavy flavor fragmentation functions from LHC data.

Radiative decays of heavy-light mesons and the $$ {f}_{H,{H}^{\ast },{H}_1}^{(T)} $$ decay constants

The on-shell matrix elements, or couplings $$ {g}_{H{H}^{\ast}\left({H}_1\right)\upgamma} $$ g H H ∗ H 1 γ , describing the $$ B{(D)}_q^{\ast } $$ B D q ∗ → B(D)qγ and B1q → Bqγ (q = u, d, s) radiative decays, are determined from light-cone sum rules at next-to-leading order for the first time. Two different interpolating operators are used for the vector meson, providing additional robustness to our results. For the D*-meson, where some rates are experimentally known, agreement is found. The couplings are of additional interest as they govern the lowest pole residue in the B(D) → γ form factors which in turn are connected to QED-corrections in leptonic decays B(D) → ℓ$$ \overline{\nu} $$ ν ¯ . Since the couplings and residues are related by the decay constants $$ {f}_{H^{\ast}\left({H}_1\right)} $$ f H ∗ H 1 and $$ {f}_{H^{\ast}\left({H}_1\right)}^T $$ f H ∗ H 1 T , we determine them at next-leading order as a by-product. The quantities $$ \left\{{f}_{H^{\ast}}^T,{f}_{H_1}^T\right\} $$ f H ∗ T f H 1 T have not previously been subjected to a QCD sum rule determination. All results are compared with the existing experimental and theoretical literature.