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.

Erratum to: Forward Higgs production within high energy factorization in the heavy quark limit at next-to-leading order accuracy

A correction to this paper has been published: https://doi.org/10.1140/epjc/s10052-021-08902-6

Forward Higgs production within high energy factorization in the heavy quark limit at next-to-leading order accuracy

We use Lipatov’s high energy effective action to determine the next-to-leading order corrections to Higgs production in the forward region within high energy factorization making use of the infinite top mass limit. Our result is based on an explicit calculation of real corrections combined with virtual corrections determined earlier by Nefedov. As a new element we provide a proper definition of the desired next-to-leading order coefficient within the high energy effective action framework, extending a previously proposed prescription. We further propose a subtraction mechanism to achieve for this coefficient a stable cancellation of real and virtual infra-red singularities in the presence of external off-shell legs. Apart from its relevance for direct phenomenological studies, such as high energy resummation of Higgs $$+$$ + jet configurations, our result will be further of use for the study of transverse momentum dependent factorization in the high energy limit.

The QCD trace anomaly at strong coupling from M-theory

Obtaining a lattice-consistent result for the temperature dependence of the QCD conformal anomaly from a top-down M-theory dual (valid) for all temperatures – both, $$T<T_c$$T<Tc and $$T>T_c$$T>Tc – of thermal QCD at intermediate gauge coupling, has been missing in the literature. We fill this gap by addressing this issue from the M-theory uplift of the SYZ type IIA mirror at intermediate gauge/string coupling [both obtained in Dhuria et al. (JHEP 1311:001, 2013)] of the UV-complete type IIB holographic dual of large-N thermal QCD of Mia et al. (Nucl Phys B 839:187, 2010), and comparing with the very recent lattice results of Bazavov et al. (Phys Rev D 97(1):014510, 2018). Estimates of the $$\mathcal{O}(R^4)$$O(R4) higher derivative corrections in the $$D=11$$D=11 supergravity action relevant to considering the aforementioned M theory uplift in the intermediate ’t Hooft coupling (in addition to gauge coupling) limit, are also presented. We also show that after a tuning of the (small) Ouyang embedding parameter and radius of a blown-up $$S^2$$S2 when expressed in terms of the horizon radius, a QCD deconfinement temperature $$T_c=150$$Tc=150 MeV from a Hawking–Page phase transition at vanishing baryon chemical potential consistent with lattice QCD in the heavy-quark limit, can be obtained.

Nonleptonic and semileptonic $${\Lambda _b} \rightarrow {\Lambda _c}$$ transitions in a potential quark model

Nonleptonic and semileptonic decay widths of $${\Lambda _b} \rightarrow {\Lambda _c}$$Λb→Λc are analyzed within heavy quark limit and Isgur-Wise formalism. A modified QCD Cornell interaction with the additional logarithmic term in the hyperspherical coordinates is considered and the masses of heavy flavour baryons are calculated. The obtained masses are consequently employed to study the rates of $${\Lambda _b} \rightarrow {\Lambda _c}$$Λb→Λc. The achieved results are motivating.

Symmetry-breaking corrections to the form factors for heavy-to-heavy B-meson at large recoil

The present study investigates the decay of B to heavy meson using the soft collinear effective theory. By assigning different loop momenta, the factorization has been tested and it is found to be valid to all orders in the perturbation theory. It is noted that theory contains one hard collinear and two soft modes depending upon virtuality of different momenta. In the next step, symmetry-conserving relations (in heavy quark limits) to the form factors have been studied. These relations are then used to parametrize the form factors to get symmetry-breaking corrections. These symmetry-breaking corrections can be calculated using perturbative (vertex corrections) as well as nonperturbative (hard spectator interactions) QCD. It is found that in the heavy quark limit, these symmetry contributions do not contribute to the form factors that appear in physical observables for the case of [Formula: see text] decays which are contrary to the heavy-to-light meson decays.

Charmed dibaryon resonances in the potential quark model

Charmed dibaryon states with the spin-parity [Formula: see text], and [Formula: see text] are predicted for the two-body [Formula: see text] ([Formula: see text], [Formula: see text], or [Formula: see text]) systems. We employ the complex scaling method for the coupled channel Hamiltonian with the [Formula: see text]-CTNN potentials, which were proposed in our previous study. We find four sharp resonance states near the [Formula: see text] and [Formula: see text] thresholds. From the analysis of the binding energies of partial channel systems, we conclude that these resonance states are Feshbach resonances. We compare the results with the [Formula: see text] resonance states in the heavy quark limit, where the [Formula: see text] and [Formula: see text] thresholds are degenerate, and find that they form two pairs of the heavy-quark doublets in agreement with the heavy quark spin symmetry.

Quasi-Exact Solutions for Generalised Interquark Interactions in a Two-Body Semi-Relativistic Framework

We consider the generalised Cornell, Song-Lin and Richardson interquark interactions in a semi-relativistic two-body basis which originates from the spinless Salpeter equation and is valid for heavy quark limit. In our calculations, due to the complicated nature of arising differential equations, we use the quasi-exact ansatz technique and thereby report the ground-state solution.