Geoffrey T. Bodwin

Rigorous QCD predictions for decays of P wave quarkonia

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 amplitude for the heavy quark and antiquark to be in a relative color-octet S-wave state. We predict all of the light-hadronic and electromagnetic decays rates of the [chi][sub c] and h[sub c] states in terms of two phenomenological parameters.

Higgs boson decays to quarkonia and the

In this paper we discuss decays of the Higgs boson to quarkonia in association with a photon. We identify a new mechanism for producing such final states in Higgs decays that leads to predictions for the decay rates that differ by an order of magnitude from previous estimates. Although the branching ratios for these processes are still small, the processes are experimentally clean, and the H \to J/\psi+gamma decay should be observable at a 14 TeV LHC. We point out that quantum interference between two different production mechanisms makes the decay rates sensitive to the HQQbar couplings. Consequently, measurements of the H \to J/\psi+gamma decay rate would allow one to probe the Higgs-charm coupling directly at the LHC. We discuss the experimental prospects for the observation of these decays and for the direct measurement of the Hccbar coupling.

H\bar{c}c

We present a new computation of S-wave color-singlet nonrelativistic QCD matrix elements for the J/{psi} and the {eta}{sub c}. We compute the matrix elements of leading order in the heavy-quark velocity v and the matrix elements of relative order v{sup 2}. Our computation is based on the electromagnetic decay rates of the J/{psi} and the {eta}{sub c} and on a potential model that employs the Cornell potential. We include relativistic corrections to the electromagnetic decay rates, resumming a class of corrections to all orders in v, and find that they significantly increase the values of the matrix elements of leading order in v. This increase could have important implications for theoretical predictions for a number of quarkonium decay and production processes. The values that we find for the matrix elements of relative order v{sup 2} are somewhat smaller than the values that one obtains from estimates that are based on the velocity-scaling rules of nonrelativistic QCD.

coupling

In this erratum, we correct several errors in Ref. [1]. In Eqs. (6.25), (6.26), (6.27), (6.28b), and (6.30) of Ref. [1], the denominator factor 81 should be written as 27(D−1), where D is the space-time dimension. The factor D− 1 arises from the projection of bilinears of p onto S-wave states. Here p is one-half the relative momentum of the quark and antiquark in the quark-antiquark rest frame. Specifically, the S-wave projections yield

Improved determination of color-singlet nonrelativistic QCD matrix elements for S -wave charmonium

We compute leading-power fragmentation corrections to J/ψ production at the Tevatron and the LHC. We find that, when these corrections are combined with perturbative corrections through next-to-leading order in the strong coupling constant α(s), we obtain a good fit to high-p(T) cross section data from the CDF and CMS Collaborations. The fitted long-distance matrix elements lead to predictions of near-zero J/ψ polarization in the helicity frame at large p(T).

Order-

We present two methods for computing dimensionally-regulated NRQCD heavy-quarkonium matrix elements that are related to the second derivative of the heavy-quarkonium wave function at the origin. The first method makes use of a hard-cutoff regulator as an intermediate step and requires knowledge only of the heavy-quarkonium wave function. It involves a significant cancellation that is an obstacle to achieving high numerical accuracy. The second method is more direct and yields a result that is identical to the Gremm-Kapustin relation, but it is limited to use in potential models. It can be generalized to the computation of matrix elements of higher order in the heavy-quark velocity and can be used to resum the contributions to decay and production rates that are associated with those matrix elements. We apply these methods to the Cornell potential model and compute a matrix element for the J/psi state that appears in the leading relativistic correction to the production and decay of that state through the color-singlet quark-antiquark channel.

v^4

Recent measurements by the Belle Collaboration of the exclusive production of two charmonia in e(+)e(-) annihilation differ substantially from theoretical predictions. We suggest that a significant part of the discrepancy can be explained by the process e(+)e(-)-->J/psi+J/psi. Because the J/psi+J/psi production process can proceed through fragmentation of two virtual photons into two cc pairs, its cross section may be larger than that for J/psi+eta(c) by about a factor of 3.7, in spite of a suppression factor alpha(2)/alpha(2)(s) that is associated with the QED and QCD coupling constants.

corrections to

We calculate the decay rates of {ital B} mesons into {ital P}-wave charmonium states using new factorization formulas that are valid to leading order in the relative velocity of the charmed quark and antiquark and to all orders in the running coupling constant of QCD. We express the production rates for all four {ital P} states in terms of two nonperturbative parameters: the derivative of the wave function at the origin and another parameter related to the probability for a charmed-quark--antiquark pair in the color-octet {ital S}-wave state to radiate a soft gluon and form a {ital P}-wave bound state. Using existing data on {ital B} meson decays into {chi}{sub {ital c}1} to estimate the color-octet parameter, we find that the color-octet mechanism may account for a significant fraction of the {chi}{sub {ital c}1} production rate and that {ital B} mesons should decay into {chi}{sub {ital c}2} at a similar rate.

S

We improve the theoretical predictions for the decays of the Higgs boson to an

-wave quarkonium decay

S