Related papers: Power counting in exclusive quarkonium decays
Exclusive processes at large momentum transfer Q factor into perturbatively calculable short-distance parts and long-distance hadronic wave functions. Usually, only contributions from the leading Fock states have to be included to leading…
The new approach to decays of heavy quarkonia, based on factorization and expansions in powers of the relative velocity of the valence quarks is reviewed.
We show that although there is no infrared divergence in exclusive P-wave quarkonium decays, the colour octet contribution is no less important than in the inclusive decay. Results from more proper calculations with only colour singlet…
The importance of including colour octet contributions in describing decay and production of quarkonium states is briefly discussed for two cases : the radiative decays of the $\Upsilon$ and the production of $J/\psi$ in the inclusive $B$…
I summarize the current status of the comparison between experiment and the predictions of the NRQCD factorization approach to quarkonium decay and production. I also present the results of some recent calculations and theoretical…
Recent results in Quarkonia are reviewed, including updates on spectroscopy and $\alpha_s$, and a first look at quarkonium annihilation decays.
Recent developments in heavy quarknoium physics are reviewed in brief, including (i) nonrelativistic QCD(NRQCD), (ii) the importance of color-octet $(Q\bar{Q})$ components in the decay and the production of a physical heavy quarkonium…
The Operator Product Expansion, in conjunction with the power counting of non-relativistic field theory, is used to examine the end-point region of the radiative decay of heavy quark bound states with $^3S_1$ quantum numbers,…
Most previous calculations of the annihilation decay rates of heavy quarkonium were based on factorization assumptions that were unproven and, in some cases, even incorrect. The recent development of a general factorization formula for…
Recent advances in our understanding of the higher-wave quarkonia have generated much interests in quarkonium physics. However most are devoted to inclusive decays and productions. Experimental data of several two-body exclusive decay…
We consider a different power counting in potential NRQCD by incorporating the static potential exactly in the leading order Hamiltonian. We compute the leading relativistic corrections to the inclusive electromagnetic decay ratios in this…
We present a new factorization theorem for the decay rates of P-wave states of heavy quarkonia. Infrared logarithms that had appeared in previous perturbative calculations of P-wave decays are absorbed into a quantity that is related to the…
We present a phenomenological analysis of higher Fack state contributions to the $\chi_{cJ}$ decays by using the recent BES experimental data. It is found that the higher Fock state $\mid (c\bar{c})_{8}g>$ makes an important contributions…
In this talk I review the recent progress made in the calculations of quarkonia production in fixed target experiments. NRQCD organizes the calculations in a systematic expansion in $\alpha_s$ and $v$, the relative velocity between the…
A brief summary of outstanding theoretical issues and recent results from the QCD factorization approach to exclusive hadronic B decays is provided.
We calculate the ${\cal O}(\alpha_s^3)$ short-distance, QCD collinear-factorized coefficient functions for all partonic channels that include the production of a heavy quark pair at short distances. This provides the first power correction…
I review recent progress in the calculation of inclusive quarkonium decays in the framework of QCD nonrelativistic effective field theories and in relation to the experimental measurements.
The role of higher Fock-state contributions to exclusive charmonium decays will be discussed. It will be argued that the J/Psi (Psi') decays into baryon-antibaryon pairs are dominated by the valence Fock-state contributions. P-wave…
Some recent issues in the theory of heavy quarkonium are discussed. Many of these deal with the need to extend the description of charmonium and bottomonium states beyond the simple quark-antiquark picture. Some recent progress on radiative…
We show that some NRQCD colour-octet matrix elements can be written in terms of (derivatives of) wave functions at the origin and non-perturbative universal constants once the factorization between the soft and ultrasoft scale is achieved…