Tetraquark molecular states in the DsD̄s1 and Ds∗D̄s0∗ mass spectrum

In this work, we construct the color-singlet-color-singlet type four-quark currents to investigate the [Formula: see text] and [Formula: see text] tetraquark molecular states with the [Formula: see text] and [Formula: see text] via the QCD sum rules and obtain satisfactory results. We can search for the [Formula: see text] and [Formula: see text] tetraquark molecular states with the [Formula: see text] and [Formula: see text] at the BESIII and Belle II in the future.

Associated Charmonium-Bottomonium Production in a Single Boson e+e− Annihilation

The production cross sections of J/ψηb, Yηc pairs in a single boson e+e− annihilation have been studied in a wide range of energies, which will be achieved at future e+e− colliders. The main color singlet contributions to the production processes are taken into account, including the one loop QCD contribution.

Comprehensive studies of ϒ inclusive production in Z boson decay

In this paper, we present a comprehensive study of ϒ inclusive production in Z boson decay, including the first complete next-to-leading-order calculations of the color-octet (CO) contributions. With the inclusion of the newly-calculated remarkable QCD corrections, the CO processes exhibit crucially phenomenological influence on the existing predictions built on the color-singlet mechanism. We also include the exhaustive evaluations of the feed-down contributions, which remained ignored in the literature, and find them to be considerable. Summing up all the contributions, the ℬZ → ϒ(nS) + X still notably undershoot the data released by the L3 Collaboration.

Investigating the Atomki anomaly in the framework of axial (ABJ) anomaly

An anomaly observed in the 8Be nuclear transition by the Atomki collaboration hints at a light, neutral boson decaying into an [Formula: see text] pair with a mass of about 17 MeV. In this paper, we study the Atomki anomaly in the framework of axial (ABJ) anomaly. Some theoretical results indicate that the X17 particle is the color singlet pseudoscalar. We take the X17 particle as a pseudoscalar meson [Formula: see text] system which has the axial (ABJ) anomaly, where [Formula: see text] denotes the up quark. Besides this, we also give an interpretation for E38 particle with a mass of about 38 MeV as a pseudoscalar meson [Formula: see text] system. We obtain the correct masses of the two pseudoscalars by a non-perturbative mass formula.

Fiducial qT resummation of color-singlet processes at N3LL+NNLO

We present a framework for qT resummation at N3LL+NNLO accuracy for arbitrary color-singlet processes based on a factorization theorem in SCET. Our implementation CuTe-MCFM is fully differential in the Born kinematics and matches to large-qT fixed-order predictions at relative order $$ {\alpha}_s^2 $$ α s 2 . It provides an efficient way to estimate uncertainties from fixed-order truncation, resummation, and parton distribution functions. In addition to W±, Z and H production, also the diboson processes γγ, Zγ, ZH and W±H are available, including decays. We discuss and exemplify the framework with several direct comparisons to experimental measurements as well as inclusive benchmark results. In particular, we present novel results for γγ and Zγ at N3LL+NNLO and discuss in detail the power corrections induced by photon isolation requirements.

Charmonia production in W → (cc̄)Ds(∗) decays

In this paper, production of charmonium state [Formula: see text] in exclusive [Formula: see text] decays is analyzed in the framework of both leading order Non-relativistic Quantum Chromodynamics (NRQCD) and light-cone (LC) expansion models. Analytical and numerical predictions for the branching fractions of these decays in both the approaches are given. The typical value of the branching fractions is [Formula: see text][Formula: see text][Formula: see text] and it turns out that the LC results are significantly larger than NRQCD ones (approximately two or four times increase depending on the quantum numbers of the final particles), so the effect of internal quark motion should be taken into account. Some rough estimates of color-octet contributions are presented and it is shown that these contributions could be comparable with color-singlet results.

A toolbox for $$q_{T}$$ and 0-jettiness subtractions at $$\hbox {N}^3\hbox {LO}$$

We derive the leading-power singular terms at three loops for both $$q_T$$ q T and 0-jettiness, $$\mathcal {T}_0$$ T 0 , for generic color-singlet processes. Our results provide the complete set of differential subtraction terms for $$q_T$$ q T and $$\mathcal {T}_0$$ T 0 subtractions at $$\hbox {N}^3\hbox {LO}$$ N 3 LO , which are an important ingredient for matching $$\hbox {N}^3\hbox {LO}$$ N 3 LO calculations with parton showers. We obtain the full three-loop structure of the relevant beam and soft functions, which are necessary ingredients for the resummation of $$q_T$$ q T and $$\mathcal {T}_0$$ T 0 at $$\hbox {N}^3\hbox {LL}'$$ N 3 LL ′ and $$\hbox {N}^4\hbox {LL}$$ N 4 LL order, and which constitute important building blocks in other contexts as well. The nonlogarithmic boundary coefficients of the beam functions, which contribute to the integrated subtraction terms, are not yet fully known at three loops. By exploiting consistency relations between different factorization limits, we derive results for the $$q_T$$ q T and $$\mathcal {T}_0$$ T 0 beam function coefficients at $$\hbox {N}^3\hbox {LO}$$ N 3 LO in the $$z\rightarrow 1$$ z → 1 threshold limit, and we also estimate the size of the unknown terms beyond threshold.