Charm and bottom production: Theoretical results versus experimental data

TLDR: In this article, the authors present theoretical results in heavy-quark production, and compare them with available experimental data, in particular, the total cross sections, the xf and pT2 single-inclusive distributions, and results on heavy quark pair correlations in both hadroproduction and photoproduction of charm and bottom hadrons.

About: This article is published in Nuclear Physics.The article was published on 1994-12-12 and is currently open access. It has received 88 citations till now. The article focuses on the topics: Charm (quantum number).

Figures

Figure 1: Cross sections for b and c production in N collisions versus experimental results.

Table 4: Values of the parameters n and b in the ts of the xF and p2T distributions, for various choices of R, beam energy, mass, and structure functions (as discussed in the text) in proton-nucleon collisions.

Table 3: Values of the parameters n and b in the ts of the xF and p 2 T distributions, for various choices of R, beam energy, mass, and structure functions, (as discussed in the text) in pion-nucleon collisions.

Figure 17: Bottom cross sections at CDF versus theoretical predictions.

Figure 29: Transverse momentum distribution of the D D pair versus the perturbative result for the E687 experiment.

Figure 18: Bottom cross sections at D0 versus theoretical predictions.

Frequently asked questions

Q1. What are the contributions in this paper?

The authors present recent theoretical results in heavy-quark production, and they compare them with available experimental data. In particular, the authors consider the total cross sections, the xF and p 2 T single-inclusive distributions, and results on heavy-quark pair correlations in both hadroproduction and photoproduction of charm and bottom hadrons. 

Q2. What are the default values of the charm and bottom masses?

The default values of the charm and bottom masses are 1.5 and 4.75 GeV, respectively, and the default choices for the factorization scale F and the renormalization scale R areR = mc; F = 2mc (2.6)for charm andR = F = mb (2.7)for bottom. 

Q3. Why did the authors not try to extend the available parton densities to smaller Q2 values?

Due to the large uncertainties that one nds in charm production from renormalization scale and mass dependence alone, the authors found that it was not worth while to try to extend the available parton densities to smaller Q2 values. 

Q4. How did the authors rescale the pT curves?

As for the B-meson di erential pT distribution, shown in g. 19, the authors convoluted the b quark theoretical curve with a Peterson fragmentation function [43], using = 0:006 [53], and the authors rescaled the curves by a constant factor of 37.5%, to account for the expected fraction of B mesons of a given charge. 

Q5. What is the e ect of the Peterson form?

Thanks to the factorization theorem, this e ect can be described by convoluting the partonic cross section with a fragmentation function, which the authors choose to be of the Peterson form [43]. 

Q6. What is the way to compare the experimental results with the measured ones?

A possible way of comparing the experimental results with QCD predictions is that of tting the theoretical distributions using the same functional forms, eqs. (3.1) and (3.2), and then comparing the values of the t parameters obtained in this way with the measured ones. 

Q7. Why was it considered unlikely that perturbative calculations could describe charm production data?

This was mostly due to the fact that it was considered unlikely that perturbative calculations could well describe charm production data (because of the smallness of the charm quark mass), and furthermore, because of limited experimental information on b production. 

Q8. What is the t of the form in eq. (3.3)?

This implies that the data are well tted by the form in eq. (3.3), since this form gives a good t to the theoreticaldistributions.